# Progress report from those with Grooves on the cylinder head



## ny_fam (Apr 3, 2004)

Know few had tried these and had good results with similar list of mods. I wanted to provide an update and look for some new options to fine tune things.
After driving the car for a season with the list of mods and changed including the grooves in the cylinder head, I'm please with the power increase, but the dyno chart shows I'm running lean 14:1 from 2k to 6k then goes rich. I suspect an air leak ?
My list of mods made at the same time the grooves where done:
* Self ported head, polished chambers ( but didn't get a valve job at this time)
* Adjustable cam gear
*Kent Gs2 cam (based on the lift measurements and the internet user claiming to have the same cam with the same markings)
*Increased compression to 9.5:1
*All out ported A1 intake manifold ( flows %25 more than stock)
* A2 throttle body
* custom intake air tube
* new Mercedes brass 190E injectors

Few things i have noticed:
1) the engine runs cool(er) lower oil temp etc then last year..
2) been running with US spec cheap gas with out destroying the engine
3) The engine wants to idle at 500 rpms, It seems that the engine would benefit from a different ignition curve, like less initial. ??
4) I don't know about mileage, I don't keep track- I don't think I'm getting worse mileage than before all my performance upgrades. So lots more power for the same mileage is good.
5) Power increase is noticeable
About Grooves: http://scientificrabbit.com/in...id=14 

My Setup info in the signature..
Winter tare down plans are to fix the grooves length and up the compression to 10:1.
I need to do a compression test too before I tare things apart.
Cheers


_Modified by ny_fam at 1:28 AM 12-14-2006_

_Modified by ny_fam at 1:30 AM 12-14-2006_


_Modified by ny_fam at 3:42 PM 12-24-2006_


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## riceatingrabbit (Aug 20, 2005)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*

cool http://****************.com/smile/emthup.gif


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## ny_fam (Apr 3, 2004)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*

Anyone else running grooves have experience to share ?
Cheers


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## wclark (Mar 28, 2001)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*

Based almost completely on the threads on this forum I decided I would do this to my race engine when it comes out this winter for some other upgrades. The other upgrades are aimed at improving intake airflow and I will probably switch to a tube exhaust header from the dual outlet cast manifold I have now. Since some of the changes reported from adding the grooves are similar to improving engine breathing it may be difficult for me to isolate the improvements from the grooves alone. However I am expecting mostly improved high RPM power from the intake and exhaust changes and anything else I see I will probably attribute to the grooving.


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## ny_fam (Apr 3, 2004)

*Re: Progress report from those with Grooves on the cylinder head (wclark)*

wclark,
When you get around to putting the grooves on please take some pictures and share them on the web here.
Cheers


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## Clint VW VW wood (Oct 28, 2003)

anyone know of a place that does this in the PNW?


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## ny_fam (Apr 3, 2004)

*Re: (Clint VW VW wood)*

I don't know of any place anywhere the specializes in putting grooves in. The people who paid someone to do the work have paid the mechanic who did the head work for them to cut the grooves.
I'd check out the inventor's website out, you should be able to connect with someone there.
http://somender-singh.com/
Cheers


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## wclark (Mar 28, 2001)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*


_Quote, originally posted by *ny_fam* »_wclark,
When you get around to putting the grooves on please take some pictures and share them on the web here.
Cheers

I will be happy to.


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## Clint VW VW wood (Oct 28, 2003)

I am interested in a picture as well.. im slightly confused about where to put the grooves.. and what length/depth. I've got a high compression 8v that I know would love to idle at 500 rpms and I just moved into a place with a garage. 
if you show me yours, I'll show you mine


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## 84_GLI_coupe (Apr 3, 2001)

*Re: (Clint VW VW wood)*

It's on my long list for the next fun engine.


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## speedtek40 (Jul 8, 2005)

These are the pics ny_fam sent me


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## The Quinner (Dec 10, 2001)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*

More power to you for trying "new" things and trying to expand your understanding of things...and, I can agree that there might be more turbulence on compression...
But...what happens on the firing stroke? Wouldn't the grooves allow the "bang" to dissipate instead of being concentrated? What about the intake stroke? The exhaust stroke?
A four stroke has just that...four strokes. There is a LOT of science missing from this story.
BTW...and, I don't mean to pick you or your ideas apart...but, increasing compression does not increase turbulence. The science is that compressing any fuel/air mixture makes it burn faster and with more energy...turbulence helps to distribute the fuel more evenly within the air...ALLOWING a higher compression ratio which gives the faster burn.
In the 70s, there were a bunch of "vortex" intake manifolds and carb spigots...the idea was to more thoroughly mix the air fuel mixture...which they did. But, it was upstream of the intake valve...and, turbulence there is undesireable. Concentrating on a single point of an engine and ignoring the rest...


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## ny_fam (Apr 3, 2004)

*Re: Progress report from those with Grooves on the cylinder head (The Quinner)*


_Quote, originally posted by *The Quinner* »_More power to you for trying "new" things and trying to expand your understanding of things...and, I can agree that there might be more turbulence on compression...


OK

_Quote, originally posted by *The Quinner* »_
But...what happens on the firing stroke? Wouldn't the grooves allow the "bang" to dissipate instead of being concentrated? What about the intake stroke? The exhaust stroke?


The idea for the firing stroke is the same, a turbulante mixture burns more complete. The Grooves allow for the flame front to reach areas of the chamber(between squish pads) quicker and burn quicker. my understanding is that a quicker, cleaner burn is not as hot? Thus less hot spots - reduce the pre-ignition.
I really don;t know how the intake stroke or exhaust would benefit or be harmed by the grooves.. Any ideas here?

A four stroke has just that...four strokes. There is a LOT of science missing from this story.
FYI - See the inventors website for more of the story. And better answers.

_Quote, originally posted by *The Quinner* »_
BTW...and, I don't mean to pick you or your ideas apart...but, increasing compression does not increase turbulence.


Hey the ideas are here to be picked apart and filled in ..
Higher compression may or may not increase turbulence - it does increase the thermal efficiency.









_Quote, originally posted by *The Quinner* »_ The science is that compressing any fuel/air mixture makes it burn faster and with more energy...turbulence helps to distribute the fuel more evenly within the air...ALLOWING a higher compression ratio which gives the faster burn.


True - with the higher compression is higher heat. Faster burn possibly, not necesarly complete. With the heat comes the quicker to ignite fact, thus high octane gass(slower burn).

_Quote, originally posted by *The Quinner* »_
In the 70s, there were a bunch of "vortex" intake manifolds and carb spigots...the idea was to more thoroughly mix the air fuel mixture...which they did. But, it was upstream of the intake valve...and, turbulence there is undesireable. Concentrating on a single point of an engine and ignoring the rest...

Agreed turbulence in the intake tract reduces the VE of the entire engine.
Hope this thread doesn't indicate that Grooves solve all problems. But provides grounds for some power gains, with not all the trade offs. Note the power gains from the Grooves are not unique, you get the gains with or with out the grooves by increasing the compression.
But the advantage seen by many who have done this mod is 10:1 compression without 91 octane gas or a knock sensor ignition.
And a more smooth idle with large cam engines.
Guys on with 240 Turbo volvos are using the grooves to up the boost on the same octane gas.
Would be great if we could understand the true advantages and the reasons why. But since we can't see inside the IC engine its all an educated guess.
Cheers
ny_fam


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## The Quinner (Dec 10, 2001)

*Re: Progress report from those with Grooves on the cylinder head (ny_fam)*


_Quote, originally posted by *ny_fam* »_
Would be great if we could understand the true advantages and the reasons why. But since we can't see inside the IC engine its all an educated guess.
Cheers
ny_fam

Not at all true. Combustion engineers have been looking at (and, more importantly high-speed filming) the inner workings of internal combustion engines for quite a few years now.
The problem is when someone has a theory based on a narrow set of assumptions. But...along with those assumptions and parameters, they change almost everything else. Then, they attribute any and all results to the narrow assumptions and parameters.
A complete cylinder head rebuild with a mild P&P alone...without any grooves...will do most of what is claimed. That is, a great deal of work is done to restore the components to specification (a "stageI" or mild P&P is really nothing more than removing the flaws that are a by product of the manufacturing process). But...this restoration is ignored and all gains are attributed to the "outside the box" thinking.
I did read the inventor's info...this time and at least once before when you posted the links. As a scientist, I see all sorts of flaws in the process which make me skeptical. A more methodological approach would go a long way to legitimizing the proposal and arguments made. The "scientific method" is missing from this science. There are too many variables that are not controlled in the experimental phase...so, the conclusions are suspect.


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## wclark (Mar 28, 2001)

*Re: (The Quinner)*

If you are worried about it, do the science thing and publish your results.


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## The Quinner (Dec 10, 2001)

*Re: (wclark)*


_Quote, originally posted by *wclark* »_If you are worried about it, do the science thing and publish your results.

I'm sorry if I said something to make you defensive...
No...I'm certainly not worried about this subject...other than the fact that it represents many of the classic pseudo-science traits...vague experimental processes with sharp conclusions. This is exactly why "new" things are published and presented to peers...so the processes and conclusions can be critiqued and, possibly duplicated.
I don't have any wedge-head engines...almost everything I am working on is a semi-hemi design...and, one pent-roof design. In both of those cases, I can ask myself: what are the design goals? In the hemi design, it's swirl...the pent-roof, it's tumble. Both are age-old methods of accomplishing the numerous (and, sometimes conflicting) goals of internal combustion. It's not JUST turbulence...it's also the ability to charge the system - to evacuate the system - and, to make reasonable power in between. Compromising any of this is counter to MY goals...and, I can argue that grooves will affect most of those things...certain designs will be affected more than others.
In the past few days, out of curiosity, I've done a lot of googling on the issue. I still can't find anyone who has done controlled before/after empirical testing. Even Somender-Singh has not done **good** controlled testing.


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (The Quinner)*

I agree Quinner. I am a mechanical engineer that owned watercooled VWs for 25 years. The internet is full of info that is skewed or incomplete with no scientific testing. Seat of pants and it sounds better. Again not knockning the combusion chamber grooves. You are in the right path. About 10 years ago a company (BMVW?)working with BMW car engines, had an article in European car magazine about this subject. I don't remember there name, but will find it in my old magazines and post. They lathe cut grooves on the back side of the intake valves and also cnc large deap arching grooves in the combustion chanmber...not two small grooves. The results were documented and impressive. Emmisions lower, power was up, detination down, cooler running, etc. I will try and find the article..
I have tried many things over the years, some worked for certain things.
The Tornado (bent sheet metal like a vortex in the air induction tube between the air sensor and the throttle body) gave better throttle resonse (torque) and gas mileage 2.0 mpg ave. but worse full throttle power.
Raising the compression improves almost every engine response, including ping/detination. power, thermal efficiency, fuel eff., lower emissions (except nitrogen oxides if temps soar). 
Water/alcohol injection works well for this (not the cheap simple kind working only off engine vacuum (little vacuum at full throttle), but the high pressure type.
I have found a small simple pulse valve (on intake manifold)(Ecotek) from England that works well for part throttle (idle is unaffected, good idle and emmisions)and full throttle unaffected. 1.5 mpg increase and better part throttle response, same idle and full throttle.
MSD ignition helped. Multiple sparks at low rpm...idle emissions dropped drastically, rev limit (for safety, adjustable timing from the dash (with a module), crisper throttle response, better full throttle. Gas mileage + 1.5 mpg. tested


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (Ben B (Bengineer))*

checking in


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## wclark (Mar 28, 2001)

*Re: (The Quinner)*

In otherwords you have nothing to contribute but your personal doubt.
By the way, I am not defensive. If someone wants to carefully isolate this variable from all others and conduct controlled tests of the effect, if any, more power to them. I would be happy to see the results.
Lacking that, you wait, I will act.


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## Clint VW VW wood (Oct 28, 2003)

so you're saying that since no one has conducted 100% correct scientific experiments that even if people say there is a gain there isnt? I guess I just dont understand what you guys are arguing about.. people that have used the grooves have reported back the changes, and many people have used the grooves. So if all these people have used them in success why do you have to be so skepticle? Looks like a duck, sounds like a duck.. it's a duck
edit:
I asked my cousin, he said it was a duck too


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## The Quinner (Dec 10, 2001)

*Re: (Clint VW VW wood)*


_Quote, originally posted by *Clint VW VW wood* »_so you're saying that since no one has conducted 100% correct scientific experiments that even if people say there is a gain there isnt? I guess I just dont understand what you guys are arguing about.. people that have used the grooves have reported back the changes, and many people have used the grooves. So if all these people have used them in success why do you have to be so skepticle? Looks like a duck, sounds like a duck.. it's a duck
edit:
I asked my cousin, he said it was a duck too

Did your cousin read it on the Internet? If so, it must be a duck








No...I guess I haven't been clear. I can see how grooves can accomplish some things. BUT...just what is a result of what is very unclear. I have read things like: it's hard to quantify the results of the grooves because they seem to work best with other modifications. And...I've seen examples where the "before" picture is a gunked up, carbon'd cylinder head with oil dripping all over it...and the "after" photo is of a fully ported cylinder head with a fresh valve job. Hardly an apples to apples comparison. 
I've experienced amazing things just by freshening a top end...detonation went down, mileage went up, oil consumption disappeared, etc. That was just from new guides and machined valves/seats (and new rings). Was any of this a miracle? No...I replaced worn out components with fresh ones.
Now...add grooves to the totally fresh top end...can I jump to the conclusion that the above mentioned gains are no longer due to the fresh top end...but, are now due to the grooves? 
The reality is that keeping oil out of the combustion chamber will increase power and mileage and decrease detonation.
Many of the testimonials seem to ignore the "other" work and suggest that the grooves are miracles. Or, that grooves work best with other modifications that are, by themselves, already proven to be beneficial to making power and increasing mileage (bumping compression, sealing valves, freshening rings, etc.).
So...lacking good science means that we lack the ability to quantify whether the grooves contribute to the gains, or not. They might...they might not. Keep in mind that the original poster is on a quest to discuss modifications from a scientific perspective...his website is pretty good and he seems to be open to discussion about these things.
I guess Detroit, et.al. are hiding this one along with that 150mpg carb. they've had since the 50s...


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## The Quinner (Dec 10, 2001)

*Re: (wclark)*


_Quote, originally posted by *wclark* »_In otherwords you have nothing to contribute but your personal doubt.
By the way, I am not defensive. If someone wants to carefully isolate this variable from all others and conduct controlled tests of the effect, if any, more power to them. I would be happy to see the results.
Lacking that, you wait, I will act.

I wouldn't call it doubt as much as healthy skepticism. When somebody wants me to accept their conclusions, they better be able to tell me how they came to those conclusions. If it smells funny, something might not be right.
I honestly DO hope that you will act. I'd love to see **long term** gains from such a simple mod...hell, I'm building a race bike and would take any advantage I can find. But...based on the FACTS that I know, I have many questions. Hot spots...carbon build-up...dissipating the energy of combustion...etc.


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (The Quinner)*

I still agree with Quinner. I looked at the web-site, which a lot of hard work went into. But many scientific principals and common sense was left out. The combution chambers were very polished, which is great and helps many factors discussed...but was this testing done controlled with the grooves an isolated variable...probably not. Milling the head will help with power and throttle resonse as I have done many times. 
All were saying is; why didn't you install the rebuilt, cleaned, polished head, then get a baseline of performance parameters. In gear acceleration times with an accelerometer (G-Tech, G-tech Pro) after the point of wheel spin (which negates wheel spin) and no shifts...say second gear from 20 -50 mph, which tests a broad range of the powerband, or 40-70 in third. All tests should be done on the same road, same direction, and similar outside temps, same amount of weight in the car, etc. This is how I test and many performance magazines. Then pull off the same head, groove it, then retest. this is much more scientific and controlled. 
If you can't see this then you've got a lot to learn about automotive performance and engineering. Good luck on your quest...


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (Ben B (Bengineer))*

The same test method goes for gas mileage, idle smoothness, ping resistance, etc.


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## wclark (Mar 28, 2001)

*Re: (Ben B (Bengineer))*


_Quote, originally posted by *Ben B (Bengineer)* »_I still agree with Quinner. I looked at the web-site, which a lot of hard work went into. But many scientific principals and common sense was left out. The combution chambers were very polished, which is great and helps many factors discussed...but was this testing done controlled with the grooves an isolated variable...probably not. Milling the head will help with power and throttle resonse as I have done many times. 
All were saying is; why didn't you install the rebuilt, cleaned, polished head, then get a baseline of performance parameters. In gear acceleration times with an accelerometer (G-Tech, G-tech Pro) after the point of wheel spin (which negates wheel spin) and no shifts...say second gear from 20 -50 mph, which tests a broad range of the powerband, or 40-70 in third. All tests should be done on the same road, same direction, and similar outside temps, same amount of weight in the car, etc. This is how I test and many performance magazines. Then pull off the same head, groove it, then retest. this is much more scientific and controlled. 
If you can't see this then you've got a lot to learn about automotive performance and engineering. Good luck on your quest... 

I can tell you why I will not do it. Time and cost. I need to pull the drievtrain this winter to replace a few things, clean up the chambers, match the intake ports to the new manifold and add new intale manifold and exhaust headers. Removing then installing the engine, plus removing and reinstalling the head is a lot of work, plus there is the cost of the one-time-use materials. I dont plan to do it twice for someone elses amusement on my dime. Also, dyno time isnt cheap and I dont plan to pay twice for it, again for someone elses amusement. I find all the data I need with my Innovate LM-1 and hillclimb results but in that envrionment there are too many external variables to come to any valid conclusions that would satisfy a scientific claim, even if the grooves were the ONLY change to the engine. I do not have any intention of trying to produce killer 20 year old 1.8 litre 8v counter flow head CIS-E engines for profit. Just one copy that kicks some SP4 butt at Ascutney, Okemo, Burke and Philo on a budget that includes only one set of dry race tires per season.
I will leave the proof to the better funded academics. However as I can think of no reason on earth how someone could make a business case for funding a controlled study of these grooves on one of these engines, I dont plan to hold my breath for the results. 


_Modified by wclark at 10:06 AM 12-24-2006_


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## ny_fam (Apr 3, 2004)

*Re: (Ben B (Bengineer))*

Is see my error in how I was talking about the groove technology and potential results. I do know a little on how to conduct an valid experiment and my groove work is not a valid scientific experiment. How ever nice it would be to have a scientific experiment done with the VW 8v head with and with out grooves, I'm with wclark - that will have to be on some one else dime. This VW stuff is a hobby for me, and thus has a tight budget and time restrictions placed on my time fiddling. 
Thanks The Quinner and Bengineer for your feed back and support. I'll need to make the proper changes to the scientific rabbit pages to reflect the non-proven groove testing and theory. I had put the info on that site to stir conversation and more testing. It seems to have done both








I have modified the original post to reflect the non scientific test with grooves here.
And since I treat my vw as a experiment its all good.
Bengineer:
thanks for sharing your experience and test results. I'd like to post the content on the scientific rabbit as an article if you don't mind.
you mentioned a ported audi 4000 intake manifold. I suspect thats the 4 cylinder model ? And the porting on the manifold was their any testing done before and after on it? How much was it ported ?
I tested the FOX intake and thought the audi 4000 would flow the same since it looked to be the same configuration.
Cheers
ny_fam


_Modified by ny_fam at 4:11 PM 12-24-2006_


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (ny_fam)*

No problem...just trying to get to the bottom of things with testing and sharing my over 600 timed runs with the younger guys! Anything to beat the Japanese cars (although many are nice just very different from euros). I have been a Euro car buff my whole life... 43 years.
Yes the Audi 4000 intake is a 4 cylinder, and came in two versions I know of. The early version (1983 stamped in the left front runner) had a slightly larger plenum because it did not taper toward the left (passenger side..needed for hood clearance on later Foxes and Audi 4000. The 1985 version had the tapered plenum. The latter was better for 1,8 cars or cars with porting and cams, while the earlier with bigger plenum was better for 2.0L cars and stock head and cams.


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (Ben B (Bengineer))*

As I recall the difference between the GTI intakes was about 0.3 sec. in the 1,000 ft drag and 0.4 sec in the 1/4 mile. This is comparing the VW intake with the Audi 4000 on the above rabbit GTI with the listed mods. Both intakes were ported to about 32 mm internal diameter runners. Keep in mind the VW intake casting had more taper (larger at plenum end, and much larger at throat of the plenum (where the runners join the plenum). This made the effective runner length shorter and lost overall torque compared to the Audi intake. Remember if more displacement were used , more compression, or cams with higher rpm range... then the result will change.
This is a big difference...for each 0.1 sec a car legth difference in the 1/4 mile). 
Both intakes were tested when cool (iced between runs), which helps by a couple tenths of a sec.


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## Clint VW VW wood (Oct 28, 2003)

why not just build a "sleeve" that fits over the intake and leaves about half an inch of space all around it, then you just plumb it into the coolant system (or it's own) and vioula, CAI! Thats just crazy talk though.
Grooves are something I would try if Im already going to be taking the motor apart, not something I would take it apart to do.


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (wclark) Hard Work*

The path to automotive performance enlightenment and true knowledge is a slow, tedious and expensive one. I have spent countless hours and money on spark plugs, air filters, induction systems, exhausts, ignition systems, cams, compression ratios,etc, etc. Some may say this is a waste or time not well spent...I personally think not. Once one knows what works and why, then you can progress and go beyond. 
I understand why someone would not want to tear off a head just for two small groves per cylinder.
The combustion grooves are a good idea, and there is evidence that shows it helps...how much we don't know. It sounds like we would all like to know what the actual effect is. 
I would suggest that several grooves would be better than two...but who knows. That would require a lot of time and careful testing.
I will try and find the article mentioned before that was in European Car many years ago, and post it for all of us. 
Most of the Auto Manufacturers have experimented with fast burn heads, increased swirl 2 valves/cyl. and 3, tumble (4 valve/cyl), special spark plugs, recessed intake valves, small unusually shaped combustion chambers, squish zones, etc, etc. We have seen some come to the market. Look at the ABA engine the late 96 heads have large swirl sections in the intake ports. Several different pistons quench pads have been used on the aba piston tops. Intersting stuff for sure. 
Search for Feuling (spelling?) V8 heads and you will see some amazing verified results...I would love to do this to the water-cooled head. A small figure eight combustion chamber with about 11:1 cr, lots of squish zones, use 89 octane and make much more power !!!!!


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## ny_fam (Apr 3, 2004)

*Re: (wclark) Hard Work (Ben B (Bengineer))*

What year Audi 4000 intake did you end up using? 
When you did the porting of the runners did you do any flow tests before and after? 
Have any test data sheets to share ?

Cheers
ny_fam


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: (ny_fam)*

I used the later Audi 4000 intake (with side taper). Did not do flow testing...didn't need to and I will explain. I also had ported another Audi intake to the max and that was slower on the car (ports too big for this size and tuning of engine). Bigger is not always better...*there is an ideal size or adjustment of each piece of your car to maximize acceleration...your challenge is to find them.*
The flow testing and dyno runs are great to see what is changing and where (rpm), but the bottom line is what is the difference in acceleration in the car through proper testing. I can change components to get 5 more peak hp and the car slows by 0.2 tenths in the 1/4 mile. Why, because the overall torque dipped lower in the rpm range used.
The highest flow intake does not mean that it will make your car any faster. It might if that is a restrictive point, but if the ports were ground too large then acceleration times may worsen. I see adds about air filters that flow 700 cfm, and why would you want to put that on a car engine that only pulls 90 cfm? It does not work that way due to the car as a group of sub-systems all working at the same time for acceleration (intake manifold, cam(s), induction, exhaust system/downpipe/manifold, cam, ignition, rotational inertia (wheels/tires, brake rotors/drums/flywheel, etc.).
When you have a stock head and cam, then a very high flow intake manifold might work the best. The exhaust sytem also has interaction with the induction components. 
I will give an example: The same Rabbit GTI I told you about was sold several years later to get a Scirocco II. Before I sold the car I removed a few of the special parts that I had custom fabricated or modified.
I did performance runs (in 2nd and 3rd gear (20-70 mph), so only one shift and no wheel spin) times were around 8.6 sec. with mods. I left the TT 2 inch exhaust system, except for the dual TT downpipe and replaced it with the dual factory downpipe that was smaller diameter and merged sooner at the bottom bend. On the induction side I swapped the intakes from the mod Audi 4000, back to the original VW with stock throttle body, also placed the stock clean paper air filter and installed the inlet air heat plenum to the air box. The times increased by over 4 seconds in the 20-70 pmh runs (thats huge). Do you see how a few critical pieces can affect the total airflow. The ideal set-up would be that all parts worked together, in the rpm range used for the test. The swapped parts restricted the air flow on the inlet/induction and outlet/exhaust sides for drastic results.
Keep in mind the car had the same ported/polished head (Techtonics (TT), with the same G cam, the same exh. sytem except the downpipe, and the intake manifold swap (and induction pieces back to stock). 
This is why all pieces of the system interplay and matter. This is also why you hear many people wondering why a certain part didn't work the same on their car as a friends. The air sytem flows only as much as the restrictive point(s). If the passages are made too large then you will loose velocity and loose torque and slow acceleration. Find the optimum point. 
Fuel adjustments, ignition settings, wheels, etc, were all the same on the GTI test car.... BUT WILL NEVER BE THE SAME ON DIFFERENT CARS.
Not at all to knock your hard work on all the intake maniflods tested, shows a lot of insight and details not normally discovered. You are on the right path to learning what works and why.
What was the acceleration difference from the mods?


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## Longitudinal (Nov 13, 2004)

*Re: (Ben B (Bengineer))*

I see valid points above about the lack of hard empirical evidence in favor of grooving.
I am considering performing this modification to an upcoming turbo project. The turbo project is receiving a fresh ported head. If I do this, I will not be performing a back-to-back-to-back comparo between stock head, modified head, then modified grooved head. But I have had and built numerous engines with ported heads, turbo and NA. I know what I can expect regarding detonation, good ignition timing, boost pressure I can get away with, etc. If I groove the head and find that the engine behaves radically different from other engines I have built, I would have awell-grounded suspicion that the grooves are responsible for the changes over previous engines I have built. 
That said, my evidence would be qualitative, not quantitative. Like wclark, I am not in for dumping a lot of money into an old engine and a CUBIC time in multiple head R&Rs.


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## The Quinner (Dec 10, 2001)

*Re: (Longitudinal)*


_Quote, originally posted by *Longitudinal* »_That said, my evidence would be qualitative, not quantitative. Like wclark, I am not in for dumping a lot of money into an old engine and a CUBIC time in multiple head R&Rs.

I can certainly understand this...and, that's the rub with the DIY'er...
I have some concerns that go beyond the immediate gains (if there are any...and, there probably are some gains...depending on what you call a gain). My first and foremost concern is: what happens in 10,000 miles? 20,000 miles? 30,000...? etc...
Those grooves look a LOT like a hot spot in the short term...and, a carbon magnet in the long term. It's true that manufactureres have tried all sorts of interesting things...many of which have shown up in production. NONE of them (AFIK) have the sharp details of a groove (even if the edges are radiused, it's still a very "abrupt" feature).
If you're building a race engine that gets torn down every few hours of operation, that's fine...the benefits might remain. However, for those of use who can't afford to do the above mentioned testing, is it realistic to think that we'll tear down our engines often enough to retain any benefits that might be there?
So...not only do we need to worry about any initial gains being there...we should worry about the long-term gains or losses...IF we're going to try to run an engine long-term...
An analogy might be: it's easy to double your horsepower by adding a TON of nitrous to a system...but, how long will the system last with permanent NOS? I.e., there's more to it than showing an initial gain...what are the longer term effects?
The inventor's initial goal was to improve the combustion processes of the old technology engines that are common in his country. Poor tolerances and worn components are the norm...not the exception. That is a standard recipe for carbon build-up and poor combustion due to oil contamination. Experience tells me that the grooves will carbon over very quickly under such circumstances.


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## SallyB (Jan 1, 2007)

*stable low speed flame propogation*

Here’s what the Engine Masters Challenge 2006 3rd place finisher had to say about the grooves.

_Quote »_...and long story short, it works.
The increases in low end torque and stable low speed flame propogation are valid and is the increase in detonation resistance. Idle vacuum increases a bit too.
There are not really any HP benefits at the top of the RPM window but more so at the bottom and mid range.
I used them at EMC this year and two years ago with good results, our combo was pulled down to 1,900 RPM at WOT with an 1150 dominator with out missing a beat. No detonation at 10.5 to 1 nor 12.5 to 1 on pump premium :!:


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: stable low speed flame propogation (SallyB)*

Where can we see a picture of these grooves? How many grooves, at what size, shape, and depth, and at what location in the combustion chamber? ... all important for proper function. I will search the web..
I believe the companies name that did testing on street driven 4 cyl. BMWs was *Metric Mechanic*...don't know if they are still around...will search the web. 
Quinner brought up good point of long term viability with carbon building up in the grooves...especially on older engines having oil getting into the combustion chambers. With a rebuilt head, and a block with low oil consumption, the positive results should last for quite a while. 
Keep in mind that the Engine Master Challenge was for large displacement V8 engines with very large bores. The larger the bores the more difficult for the combustion process (due to flame propagation of the longer distances across the bore, and possible heat loss /pressure loss from the distance), hence any improvement helps. These smaller engines are 1/4 to 1/5 the size so the torque results with be proportionally less. Not to curb enthusiasm
, just to clarify. 
This is a subject that definitely need further study and information gathering.


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## The Quinner (Dec 10, 2001)

*Re: stable low speed flame propogation (SallyB)*

Can we have a source for that? ...or, some more information? Honestly, I'd like to learn more...again, it would be great if such a simple modification could be shown to have value...but, I've heard plenty of other "yes, it works" claims that are short on substance.
I'm running an ancient technology, air-cooled motor at 10.5:1 and have no detonation on 92 octane pump gas with 40mm carbs feeding each cylinder. The engine design dates back to the 1920s (BMW horizontally opposed air-cooled flat twin motorcycle engine) and the combusiton chamber design was done in the late 70s (Krauser 4-valve top end for the BMW engine from MKM in Germany). I'm not necessarily that impressed with no detonation at 1900 rpms with modern, water-cooled machinery.
AND, again...what about long-term benefits? A horsepower/tuning shootout certainly doesn't address that issue.
The crux of my devils advocate position is the "I read it on the Internet, so it must be true" mentality. Over the years, it has taken many forms...the Internet is a global phenomenon that has taken snake oil international.
Whatever one thinks about big business...there's no denying that the big auto manufacturers have a huge interest in real-world efficient combustion. Lately (past ten years), it has been how to get more power from smaller engines...in the next few years, it will probably shift more towards economy without too much loss of power. Why aren't they using grooves? I once did a multi-million dollar study with designers from one of the big three (hint, #2)...I can assure you that there is plenty of outside the box thinking and that they are willing to consider about anything...IF IT WORKS.


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## SallyB (Jan 1, 2007)

*The Mad Porter*

http://460ford.com/viewtopic.php?t=6774


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## The Quinner (Dec 10, 2001)

*Re: The Mad Porter (SallyB)*

I would like to see his response to the poster who asked if there was a before and after dyno run...
SallyB's quote is literally all of the info the guy presented.


_Modified by The Quinner at 1:11 PM 1-1-2007_


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## SallyB (Jan 1, 2007)

*The Mad Porter*

I have been following this for some time now. The post by the mad porter is the most promising information to date. Too bad he doesn’t post more information on the extent of his testing.
Detonation at the EMC was so big of a problem that the rules were changed to limit compression ratios.


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## Ben B (Bengineer) (Dec 20, 2006)

*Re: stable low speed flame propogation (SallyB)*

All...found the company name that experimented and documented results of the combustion chamber grooves....Metric Mechanic (BMW, 4 and 6 cyl auto engines)..do a search abd check it out.


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## automotivebreath (Dec 28, 2005)

*Re: stable low speed flame propogation (Ben B (Bengineer))*

Correct me if I’m wrong, what I’m seeing at the Metric Mechanic site is slightly different called “surface turbulence”. Is this the same concept?


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## ny_fam (Apr 3, 2004)

*Re: stable low speed flame propogation (automotivebreath)*

Concepts do seem different to me, I think the two techniques could be used together can complement each other.
Did anyone read the article on extreme edging? That looked like a good idea also. http://fueleconomytips.com/200...re-77 
Then some discussion over at mpg research.
http://mpgresearch.info/viewfo...b291e
Example of the two ideas combined.


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## automotivebreath (Dec 28, 2005)

*Metric Mechanic*

Hi ny_fam,
How your grooved engine running?
The surface turbulence idea of James Rowe is proven and very interesting. I personally haven't tried it but know many people that have with good results.


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## ny_fam (Apr 3, 2004)

*Re: Metric Mechanic (automotivebreath)*

AB - Engine ran OK once I got all the misc issues worked out. Being a DIYer on a budget you tend on making a lot of changes all at once. And when you do that sometimes is takes a while to work through those various changes in getting a good tune.
Getting a late start I got to drive the car for 4 months this year, on 1,500 miles. 
My impressions from driving this year is that " I need more" more grooves and more compression. I found at low rpms, advanced timing, and heavy load there were signs of ping or detonation. Another vw guy found the same results and he ended up respringing the distributor to change the low rpm timing.
The head will be coming of in a few weeks, I need to extend the original grooves closer to the gasket surface, and am thinking of placing two more like in the turbobricks forum. To help induce swirl. I'll have to look at the burn patterns to see how they look and go from there. Plus I'll get the compression up to 10:1. Its 9.5:1 now.
Here is the thread of the other 8v VW Grooved head
http://forums.vwvortex.com/zerothread?id=2836330 
I wonder if the fact that the cam I've run this year may have reduced the intake velocity at low rpm, and thus created a situation where there was fuel was dropping out of the air stream. Then not getting a good burn and thus the ping. Did seem to happen with the engine temp was high, the oil temp was 100c. Not a bad temp but just the temp that the engine behaved this way.
Cheers


_Modified by ny_fam at 2:39 AM 1-7-2007_


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## automotivebreath (Dec 28, 2005)

*Re: Metric Mechanic (ny_fam)*

ny_fam,
My advice to you is to work with what you have learning to tune it to eliminate detonation. Reduce engine temperatures if possible, reduce ignition advance and add fuel at the RPM that detonation exists. Get a magnifying glass made for reading plugs, detonation will show up as tiny specks on the porcelain. 
Once you learn more about what it needs to control detonation, then raise the compression and add more grooves.


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## ny_fam (Apr 3, 2004)

*Re: Metric Mechanic (automotivebreath)*

AB,
The head needs to come off for some air flow testing I'm doing so At least I'll be extended the existing grooves 1.5mm from the gasket surface.
And doing a better job of polishing the combustion chamber.
I do know that my ignition timing was detonation limited. I also know that from my recent dyno run the air fuel was a bit lean at low rpms.
Good Advice- don't change to much. I'll try to stick to the plan.
Cheers


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## automotivebreath (Dec 28, 2005)

*Re: Metric Mechanic (ny_fam)*

If you’re taking the head off go for the extra grooves. Something like what the Volvo people are doing will work nicely. No need to raise the compression ratio much until you can eliminate the detonation, that’s the primary concern.


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