# Have MK3 cams EVER destroyed your engine?



## Weiss (Jun 21, 2004)

*Have MK3 cams EVER destroyed your VR6 engine?*

I'd like to put this theory to rest if we could. While using the stock VR6 MK3 cams and a SRI, has there ever been anyone who has actually fried pistons/valves/spark plugs, or done any sort of damage due to in part by not having any runner compensation??
I have a MK4 engine, however I'm installing a '96 MK3 engine and it has the double timing set so it's not just as easy as swapping the cams. I want to know, from experience only, if anyone has ever had a real issue. 
Thanks.


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## KubotaPowered (Jan 27, 2005)

*Re: Have MK3 cams EVER destroyed your VR6 engine? (Weiss)*

Not that I have heard of. MJM sells the single row timing kit I believe for not too much coinage. Might be worth a look.


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## VR6-GT42RS (Jun 4, 2008)

why do you want to change them.. all 174hp vr6 engines run the same cams..


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## broke_rado (Nov 5, 2008)

*Re: (VR6-GT42RS)*

All 12v VR6 OEM cams are the same. On the MK4 the flapper inside the manifold is what makes up for compensation not the cams.


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## 05JettaGLXVR6 (Jan 25, 2006)

*Re: (broke_rado)*


_Quote, originally posted by *broke_rado* »_All 12v VR6 OEM cams are the same. On the MK4 the flapper inside the manifold is what makes up for compensation not the cams.









Thank you. Im so tired of hearing about how much there different. I can take pictures of the mk3 set and mk4 set if you like.


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## EL DRIFTO (Jul 11, 2004)

*Re: (05JettaGLXVR6)*

fucin A


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## Weiss (Jun 21, 2004)

*Re: (broke_rado)*


_Quote, originally posted by *broke_rado* »_All 12v VR6 OEM cams are the same. On the MK4 the flapper inside the manifold is what makes up for compensation not the cams.









Oh snap! That settles it then. What's Foffa talking about then?


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## broke_rado (Nov 5, 2008)

*Re: (Weiss)*


_Quote, originally posted by *Weiss* »_
Oh snap! That settles it then. What's Foffa talking about then?

its foffa who ever knows what he is talking about??


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## Weiss (Jun 21, 2004)

*Re: (broke_rado)*


_Quote, originally posted by *broke_rado* »_
its foffa who ever knows what he is talking about??

LMAO.








I feel much better now. Even if there was no runner compensation, I couldn't see it making a difference. Given our crappy flow rates, I'm sure lot's of air is stacking behind the valve anyway. Plus, you look at dual plane intakes for SBC, SBF's, 4 runners are real close, and 4 are far away. I don't see them having any issues... hmm...


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## EL DRIFTO (Jul 11, 2004)

*Re: (Weiss)*

podium road race porsches tuned different cams & carbs per bank for wider powerband
you wouldn't want the same carbs on both sides
conservative oe tunes wont care, although emissions might
talkin about optimal length runners on all cylinders?


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## broke_rado (Nov 5, 2008)

*Re: (EL DRIFTO)*

If you had a wideband on every runner of ur exhaust manifold you could tune for each cylinder. http://****************.com/smile/emthup.gif


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## EL DRIFTO (Jul 11, 2004)

*Re: (broke_rado)*

oh there's some type of crank timing technology that could measure the power of each cyl on board
knock sensor could advance to the point of finding VE per cyl
continuity/amperage per spark measures the same thing


_Modified by EL DRIFTO at 5:48 AM 7-25-2009_


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## VR6-GT42RS (Jun 4, 2008)

runner compensation have we all seen in the old aluminium intake... but let me get this straight.. in the oem software they still compensate for more fuel on the rear bank.. i think on the new plastic intake(also 24v) they only have the variabel runner length to add more power from the low rpm(i dont think there is runner compensation,not even in the 24v cams) look at my r36 build..i add 6 widebands for tuning and a ems that can handle fuel on each cylinder,then you will never see the problem..







show us some broken plastic vr6 12v-24v manifolds.. it so easy to see if there is any runner compensation.. 










_Modified by VR6-GT42RS at 2:03 AM 7-25-2009_


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## EL DRIFTO (Jul 11, 2004)

*Re: (VR6-GT42RS)*

fascinating http://****************.com/smile/emthup.gif 
well for all of us without 6 widebands/haven't seen oe maps
just how much more fuel % goes back there?
any oe timing changes, rear bank?


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## VR6-GT42RS (Jun 4, 2008)

im running 3%more on cyl 1 and 5%more on 3&5 on my vr6


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## AlexiGTIVR6 (Jul 21, 2000)

*Re: (broke_rado)*


_Quote, originally posted by *broke_rado* »_All 12v VR6 OEM cams are the same. On the MK4 the flapper inside the manifold is what makes up for compensation not the cams.









MK4 12 VR6 cams have a different part # then mk3 vr6 engines.


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## crzygreek (Jul 8, 2005)

*Re: (AlexiGTIVR6)*

anyone with concrete evidence of this occurring? [email protected] got any comments?


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## [email protected] (Jul 2, 2006)

*Re: (Weiss)*


_Quote, originally posted by *Weiss* »_
Oh snap! That settles it then. What's Foffa talking about then?

Are you on crack?
The cams on MK4 are 248/242s
AND different on fron to back cylinder bank to remove the staggerd stacks that MK3 got.
The plenum vario lenght got nothing to do with this part of the pulse tuning.


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## [email protected] (Jul 2, 2006)

*Re: (VR6-GT42RS)*


_Quote, originally posted by *VR6-GT42RS* »_why do you want to change them.. all 174hp vr6 engines run the same cams..

No ALL MK4 run different cams on each bank just like ALL mk4 in europe also did on the VR5s
its a US spec cam for Mk4 12v and a Euro version for VR5 MK4


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## [email protected] (Jul 2, 2006)

*Re: (VR6-GT42RS)*


_Quote, originally posted by *VR6-GT42RS* »_runner compensation have we all seen in the old aluminium intake... but let me get this straight.. in the oem software they still compensate for more fuel on the rear bank.. i think on the new plastic intake(also 24v) they only have the variabel runner length to add more power from the low rpm(i dont think there is runner compensation,not even in the 24v cams) look at my r36 build..i add 6 widebands for tuning and a ems that can handle fuel on each cylinder,then you will never see the problem..







show us some broken plastic vr6 12v-24v manifolds.. it so easy to see if there is any runner compensation..









_Modified by VR6-GT42RS at 2:03 AM 7-25-2009_


*BACK TO 1998*








Here are the differences between the 2 valve VR engines
MK3 242* 10.2mm cam and STAGGERD 420mm runner lenght
MK4 US spec 242/248* 10.2/10.7mm lift 420/350mm runner lenght
MK4 Euro spec 242/248* 10.2/10.7mm lift 380/310mm runner lenght


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## [email protected] (Jul 2, 2006)

*Re: ([email protected])*

mk4 us spec lower mani vs mk4 eurospec lower mani








VR5 vs VR6 mk4 lenght








MK3 staggerd Compare to EURO MK4 version









Cam test for one of the MK4 VR6 cyliderbanks.
The other bank got different duration and lift
Ignore the 284* turbocam


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## VR6-GT42RS (Jun 4, 2008)

look at this foffa... 
http://www.m-t-e.de/produkte/A...x.php
i dont think that hgp designed this with runner compensation just for fun.R32/v6 intake manifold. btw when i say all 174hp models i mean from 92-98.. they all have the same part number..


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## [email protected] (Jul 2, 2006)

*Re: (VR6-GT42RS)*


_Quote, originally posted by *VR6-GT42RS* »_look at this foffa... 
http://www.m-t-e.de/produkte/A...x.php
i dont think that hgp designed this with runner compensation just for fun.R32/v6 intake manifold. btw when i say all 174hp models i mean from 92-98.. they all have the same part number..









Hi
They guy who cast those have no clue what he is doing.
He acctually is here on vortex and tried to explain why the MK3 looks like it does.
And conclusion is that for Mk3 he didnt know and for Mk4 he didnt know either.
174hp model exist to 1998-2002 with the new cams and intake


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## VR6-GT42RS (Jun 4, 2008)

so the man that you think know nothing is mr HGP him self.. the intake on the picture i the same as hgp´s no matter what you say about runner lenght.. it does not work perfect.. because if it was they dont need to add more fuel in the oem ecu on the rear bank.


_Modified by VR6-GT42RS at 8:37 AM 9-24-2009_


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## MarcoVR6SC (May 3, 2003)

*Re: (VR6-GT42RS)*

The reason why there's a fuel compensation on the rear cylinders, is because they run hotter at the back, then those at the front, not to compensate for differences in VE.


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## VR6-GT42RS (Jun 4, 2008)

*Re: (MarcoVR6SC)*

have you ever seen air fuel on each cylinder on a vr...because if you had you would know that they run leaner.. and thats nok only because off heat..


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## MarcoVR6SC (May 3, 2003)

*Re: (VR6-GT42RS)*

Could also be caused by poorer air fuel mix, the injectors for the rear cylinders are located ‘further’ away from the inlet valves, this will probably change with RPM, worse at low RPM and maybe better at high RPM, is your individual cylinder trim table 2D (RPM/LOAD)?


_Modified by MarcoVR6SC at 7:31 PM 9-24-2009_


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## [email protected] (Jul 2, 2006)

*Re: (VR6-GT42RS)*


_Quote, originally posted by *VR6-GT42RS* »_so the man that you think know nothing is mr HGP him self.. the intake on the picture i the same as hgp´s no matter what you say about runner lenght.. it does not work perfect.. because if it was they dont need to add more fuel in the oem ecu on the rear bank.

_Modified by VR6-GT42RS at 8:37 AM 9-24-2009_

HGP is just a small company in germany.
I can post some of their software files here and you can see what they do to their stuff.
Their MK3 intake manifold is the worst in history.
1:Bank compensation cut of
2ulse tunes for 12 000rpm = 80-100Whp loss before 5000rpm and then ~30whp loss vs OEM intake
3:TB angle will make 2 cylinder get less air


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## NeverEnding... (May 9, 2007)

*Re: (MarcoVR6SC)*

arguing on the internet is like winning the special olympics...even if u win, your still retarded


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## MarcoVR6SC (May 3, 2003)

*Re: (NeverEnding...)*


_Quote, originally posted by *NeverEnding...* »_arguing on the internet is like winning the special olympics...even if u win, your still retarded

But if we do not argue, what’s the use of a forum then?
PS: don’t call the people playing at the special Olympics’, retarded, and ‘you are’, is spelled you’re, not your…


_Modified by MarcoVR6SC at 9:57 AM 9-25-2009_


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## EL DRIFTO (Jul 11, 2004)

*Re: (MarcoVR6SC)*

the us sri has the rear bank with 2.7" longer runners
the 4th & 5th pulse reflection runner lengths differ about 2.5" too...
if your cam is stock, the intake valve is closed too long (unless you're @ 10K) to catch them
you end up getting the 6th reflection on the front bank alone
"so it flows better"
a super long cam^ would have the intake valve closed for a shorter period & could catch 5th reflection on front @ the same timeish the rear could catch the 4th
trying to learn this @ the expense of whoever reads it








tia
EDIT & WRONG 
30 degree change in cam duration is only 6% change in total valve closed time, which is when the air is bouncing & calculated
720 degrees - 200 degrees eff cam duration = 520 degrees closed time
30 / 520 = 5.7 %


_Modified by EL DRIFTO at 5:24 PM 10-29-2009_


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## RedDevil (Sep 21, 2001)

*Re: ([email protected])*

Foffa just because you speak/read polish doesn't mean we do.


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## EL DRIFTO (Jul 11, 2004)

*Re: (RedDevil)*

#s are resonating freq?


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## RedDevil (Sep 21, 2001)

*Re: (EL DRIFTO)*


_Quote, originally posted by *EL DRIFTO* »_#s are resonating freq?

they are intake lengths in mm for open and closed variable geometry valve.


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## GokuMk216V (Mar 13, 2021)

Lets end this! From left to right, Mk3 Cams, Mk4 Cams, Cat Cams 263/264 this is the 2,4,6 cilinders cam.


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## GokuMk216V (Mar 13, 2021)

1,3,5 cylinders cams


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