# Is 11.1 compression to high for turbo??



## team~bunny (May 16, 2002)

I have 11.1 compression and a friend of mine who is a mechanic said that he would not put a turbo on it because of the high compression, what do you turbo guys think?? keep In mind i still want reliablity out of my car as well as speed. I have a turbo and intercooler off of a eagle talon, what do you think about that? thanks 


[Modified by team~bunny, 6:38 AM 8-19-2002]


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## FlugGTI (Oct 25, 2000)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

yes.


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## 96jetta (Mar 7, 2002)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

yes unless you spend a lot of money on gas


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## cidzonetrooper (Apr 16, 2002)

*Re: Is 11.1 compression to high for turbo?? (96jetta)*

11 to 1 is way to high,try 8-5 or 9-1. you will detonate and rattle and then go boom. been there done that!!!! now im 7-1 and its happy. later


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## 2.0T (Jun 17, 2002)

*Re: Is 11.1 compression to high for turbo?? (cidzonetrooper)*

how do hondas get away with running high compression and boost??
there is a guy out here that has a civic with a j spec b16 running 11.5:1 comp and he runs 7psi on it and the cars runs 12.8 at only 7psi!!


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## samrabbit (Feb 18, 2002)

*Re: Is 11.1 compression to high for turbo?? (2.0T)*

his fuel system dont allow the engine to go lean. and he runs 113 octane. that's how.


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## HOTSKILLET98 (Mar 12, 2002)

*Re: Is 11.1 compression to high for turbo?? (cidzonetrooper)*

Listen to these guys. They know what they are talkin about. Who cares about the Hondas. Reduce it or go kaboom. 
I'll take one 7.5-1 compression spacer and a a t04E 60-1 hi fi and make my order "to go" please


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## TDIVentoDave (Oct 25, 2000)

*Re: Is 11.1 compression to high for turbo?? (2.0T)*

Well 2.0T, Eric has had 3 count 'em 3, b16 motors in his civic hatch running 7psi. that is how he gets away with boost+high comp. And he really didn't care because he gets those motors(blocks only) dirt cheap. He probably has another couple sitting at home as well! Anyway, back to the VW topic, you will probably only be able to run like 5psi of boost on 110 octane with your 11:1 comp, and by then it wouldn't be worth it to do a turbo. I personally would do a 100-shot wet n20 setup!


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## samrabbit (Feb 18, 2002)

*Re: Is 11.1 compression to high for turbo?? (TDIVentoDave)*

actually you can push 20s in boost with 11:1........just not on the street. wanna go fast for dragging? that's how.
sure, I'll share my data with you guys.


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## DwightLooi (May 16, 2000)

*There is a way to run 11.0:1 and moderate boost on 91 octane gas...*

11.0:1 is normally way too high for turbocharging. *It is on the edge of pinging threshold naturally aspirated if your combustion chamber design is not up to par.* If your chamber has a centrally located spark, compact dimensions (ie, tall roof + small bore) and broad squish decks, you can probably only run up to 11.5:1 productively on pump gas naturally aspirated anyway. Go any higher an you lose more power form of limitations in timing advance than you gain from a rise in static compression.
*There is a conceivable way to run 11.0:1 and moderate boost -- lets say 7.35 psi (0.5 bar) -- on pump 91 octane gas.* This involves a special camshaft and basically amounts to reducing effective compression via the intake cam. What your wil do is have a very long duration intake cam (probably somewhere around 260-300 degrees) but instead of using it for valve overlap, you retard it big time. Hence in effect are allowing the intake valves to stay open during part of the compression stroke. If you keep the intake vavles open for about 90 degrees into the compression stroke you have in fact roughly halved the compression ratio (actually its slight less than half more like 6.5:1 from 11:1 due to a variety of factors) because you have in fact halved the compression stroke. Less effective static compression means you can run more boost. You also get *two added benefits.* The first being that *while your compression stroke is effectively reduced, your power stroke isn't reduced at all.* This asymetry increases efficiency measurably. The second is that if you have a DOHC engine *you can "adjust" your compression simply by adjusting the intake cam timing* -- advancing the cam = more overlap + more compression, retarding the cam = less overlap + less compression.
*There is a name for this scheme. It is called the Miller Cycle.*


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## team~bunny (May 16, 2002)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

thank you very much for all the help guess ill have a turbo and intercooler up for sale soon. I'll just go with nos, but would'nt 100 shot be to much for my little stock engin? i was thinking 50 to 75 shot, or can i put more because of my high compression? thanks again for all the help!! ted


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## nycvr6 (May 4, 1999)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

No it is NOT too high. Just need a good stand alone setup, tuning and a sh!t load of high octane fuel.


[Modified by nycvr6, 1:54 PM 8-19-2002]


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (nycvr6)*

The more compression the more precise the tuning has to be and the higher the octane rating because octane helps fight detonation. The less compression the more margin of error you have in the tuning, simple as that.
Paul


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## mrkrad (Nov 9, 2000)

*Re: Is 11.1 compression to high for turbo?? (killa)*

nah the R8 uses like 12:1 with twin turbo's. Just gotta use 110-114octane.


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## DwightLooi (May 16, 2000)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

quote:[HR][/HR]thank you very much for all the help guess ill have a turbo and intercooler up for sale soon. I'll just go with nos, but would'nt 100 shot be to much for my little stock engin? i was thinking 50 to 75 shot, or can i put more because of my high compression? thanks again for all the help!! ted[HR][/HR]​I note that your salvaged turbo is from an Eagle Talon. Depending on whether that it is from a 90-94 or a 95+, that is either a Mitsubishi TD05/14B or a Garrett T25 respectively. The former is bigger, the latter is smaller. Either of these turbos, while not state of the art, should do adequately on a 2.0 engine as long as you lower your compression to at least 9.0:1 or so unless you plan going Miller Cycle. But *turbocharging an NA engine is a big project, especially when starting with a bare turbo and not someone else's prepared "kit".* You'll need custom mannifolds, downpipes, engine management and possibly a fuel system upgrade. Your high strung NA cams probably won't work well either. Plan on spending at least 10 dyno pulls getting your tuning right, getting it safe and getting it civilized. And that is if you know what you are doing.
NOS is definitely simpler to implement. For a simple, reliable setup, I am biased towards the *Venom VCN-1000* kits and an upgraded fuel pump. Dry setups are more consistent in its fuel enrichment distribution and are much less prone to leaning out on one cylinder. The kit is about $600 and a bigger fuel pump should run no more than $150. You should be able to do the work over a week end if you are not shy.
























[Modified by DwightLooi, 3:40 PM 8-19-2002]


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## team~bunny (May 16, 2002)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

What shot of nos should I put on my stock engin? I was thinking 50 or 75 would this be to much? I still want reliability, and dont want my engin to blow up or anything, I have my cam gear advanced one tooth, should i move it back and just retard my timeing by the distributor? oh ah.. I have a 25lb nos tank, 15 ft of line and a nitrus silonoid what else am I going to need to set up a dry setup? I though I woul donly need some more line 2-3ft and the little fogger and the little jets, does this sound like about it? does anyone have a good idea were I could get the rest of the stuff i need?? thanks ted


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (mrkrad)*

quote:[HR][/HR]nah the R8 uses like 12:1 with twin turbo's. Just gotta use 110-114octane.
[HR][/HR]​That comes down to what i said, the higher the compression the higher octane you'll need.


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

quote:[HR][/HR]I note that your salvaged turbo is from an Eagle Talon. Depending on whether that it is from a 90-94 or a 95+, that is either a Mitsubishi TD05/14B or a Garrett T25 respectively. The former is bigger, the latter is smaller. Either of these turbos, while not state of the art, should do adequately on a 2.0 engine as long as you lower your compression to at least 9.0:1 or so unless you plan going Miller Cycle. 
[HR][/HR]​I'd have to lean more toward the 14b, TD05H-14b to be correct, could even be from an automatic 1generation unit which would be a TD04-13b, the T25 is a little too small IMO and neither of these units use a T3 flange which is the most used flange on 4cyl motors. Sure it'd be good for now, but boost is addictive and you'll want to run something bigger. If i were you i'd just sell the turbo and get a T3 from someone around here.
Just my oppinion though.
Nitrous is also a very good choice like DwightLooi mentioned.
Paul


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## team~bunny (May 16, 2002)

*Re: Is 11.1 compression to high for turbo?? (killa)*

I whent and looked at the turbo it says TD05, I have two with both intercoolers, I think my friend might buy one to put on his bmw though, but what about the nos, what shot shoud I use? read my last post and please answer some of my questions I want to order the rest of the stuff i need tommorrow 
thanks ted


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## HOTSKILLET98 (Mar 12, 2002)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

You guys really read into the question lil too deep. Understand this guy is just trying to put on a turbo by his mechanic. There is a 99.9% chance this guy IS NOT going to:
1. get a stand alone http://****************.com/smile/emthup.gif 
2. get 113 octane fuel on a regular basis 
3. not drive it on the street








4. Change cams or timing


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## TDIVentoDave (Oct 25, 2000)

*Re: Is 11.1 compression to high for turbo?? (HOTSKILLET98)*

werd


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## nabilsx (Jun 8, 2000)

*Re:{(cidzonetrooper)} Is 11.1 compression to high for turbo?? (cidzonetrooper)*

hey (cidzonetrooper) ur CR now is 7:1?? how does it feel compared to the stock CR when ur off boost?


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## DwightLooi (May 16, 2000)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

quote:[HR][/HR]What shot of nos should I put on my stock engin? I was thinking 50 or 75 would this be to much? I still want reliability, and dont want my engin to blow up or anything, I have my cam gear advanced one tooth, should i move it back and just retard my timeing by the distributor? oh ah.. I have a 25lb nos tank, 15 ft of line and a nitrus silonoid what else am I going to need to set up a dry setup? I though I woul donly need some more line 2-3ft and the little fogger and the little jets, does this sound like about it? does anyone have a good idea were I could get the rest of the stuff i need?? thanks ted[HR][/HR]​1. I think we have a major issue here. *Do not confuse cam timing with ignition timing!!!*.
Cam timing is the angle of the camshaft in relation to the crank position. In other words, it is the timing of when your valves open and close. You adjust this by "indexing" the cam, usually with an adjustable cam sprocket. *If you have a DOHC engine it is frequently possible to adjust the intake and exhaust timing separately.* The effects can roughly be summarized as follows...
If you advance the intake cam without touching the exhaust cam you generally increase overlap -- the period of time when both intake and exhaust valves are open to some degree -- this increases top end power at the expense of low end torque. The torque curve becomes notably peakier and biases towards the high end. If you retard it in relation to the exhaust cam you improve low end torque and idle. The torque curve becomes flatter and more gently contoured. The opposite applies for the exhaust cam, but it has less effect. If you go over board doing any of the above torque plummets drastically and your engine runs like crap and spews tons of either hydrocarbons or NOx. In an SOHC engine because both intake and exhaust valves are driven off the same cam you cannot change the timing in relation to each other but only in unison. Of course you can also do this in a DOHC engine. By doing this, within a reasonable (read narrow) range of adjustment, you can shift the torque curve left or right along horizontal (rpm) axis without altering its overall shape. Going too far again causes the engine to choke and protest and run like garbage.
*The above shows a major advantage of many DOHC engines, unfortunately the 16v 1.8 or 2.0 VW engines are not among them.* These engines, while DOHC, have a timingbelt driving one cam directly and an intermediate chain driving the other cam off the one driven by the belt. Hence as so far as cam adjustments are concerned it might as well have been an SOHC design.
*Ignition timing control the firing of your spark plugs.* Anything to do with the distributor can only affect ignition timing not cam timing. All engines fire the spark plug at some point before the piston actually reaches the top. This is because it takes time for the flame to reach out and ignite the fuel/air mixture. The amount, in degrees, ahead of top dead center when the spark fires is called spark timing advance. You generally need more advance at higher rpms than at lower rpms. You will also likely want to retard timeing if you sens pinging via the knock sensors. Most modern ECU do these adjustments for you dynamically, but it starts with from a fixed starting point and adds or subtract from it. This starting point is called the *base timing*, and it is what you adjust when "tuning up" your engine. There is also no way to tell the timing you are running without a timing gun. The light flashing thing. Too much timing advance leads to pinging. Too little and your engine will not produce the most power that it can all else being constant.
---
2. The difference between a dry and a wet NO2 setup is that *a dry setup injects NO2 gas only somewhere in the intake pipe (prefably at least 8" from the throttle body or plenum entrance) but uses your regular fuel injectors to supply the additional fuel.* Generally this is done with a supplimentary controller that intercepts your ECU's fuel injector pulses and artificially lengthens them for addtional fuel enrichment. It is called "dry" because nothing ahead of the fuel injectors ever got wet with gasoline. The *cheapest dry setup is the VCN-1000 kit from Venom*; you can't rig up a DIY system because you need that electronic box and unless you are an electrical engineer familar with both the ECU in your car and signal processing circuitry you can't build one.
*In a wet setup, you inject both NO2 and additional gasoline in the intake pipe.* The entire intake tract that normally carries only air gets "wet" with gasoline. You do not need an electronic controller but merely have to ensure that you inject the right proportion of gasoline and NO2. You do so by seleting the right nozzle size for both using your engine's fuel pressure rating and the NO2 shot desired as guidelines. This is much less precise, both in the amount of additional fuel delivered and its distribution. Because sometimes the fuel is not homogeneously distributed after snaking its way through your intake, throttle, plenum and runners. This causes some cylinders to run leaner than others.
*The ultimate no-no in NO2 usage is leaning out.* If you do not have enough additonal fuel the combustion temperature can sky rocket and that is when you blow things up. If unsure, always err towads the rich side. You'll never blow up if you are rich so long as your pistons, rods, journals, crank, etc don't break. And they usually won't for 50hp shots. Note also that 50 shot or 100 shot or whatever, are references to the fact that the amount of additional combustibles (aditional fuel + oxygen from N02 gas) will theoretically unleash enough additonal energy for 50 more horsepower. In reality you won't get exactly that and most likely more like 75% to 85% of that shot in real horsepower increases at the crank, even less at the wheels. Nevertheless, NO2 use is one of the cheapest, highest yield power enchancing schemes, mainly because it is air independent.
























[Modified by DwightLooi, 1:18 AM 8-20-2002]


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## 96jetta (Mar 7, 2002)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

that was really well written and well worded, but I have one question: How long did that take you to write?







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


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## DwightLooi (May 16, 2000)

*Re: Is 11.1 compression to high for turbo?? (96jetta)*

A lot of it, roughly 70% of the stuff, I copied and pasted from something else I wrote a long time ago.


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## 96jetta (Mar 7, 2002)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

"A lot of it" what














I understand, I'm tired too. go to bed, get some rest. big day tomorrow


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

Ok, look closer and you'll notice an "H" at the end of the TD05, it's actually a TD05H, so, if you took it from a stock car, you have a 14b, unless it was an evo which came with a TD05H-16G, a turbo that is capable of 375hp.
Dwight, very well written, but you can still time the intake cam and the exhaust at different times like the "regular" DOHC" motors, kent cams makes adjustable chain gears for our cars.
Paul


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## psi (Oct 18, 2001)

*Re: Is 11.1 compression to high for turbo?? (killa)*

This kid won't make it down the block with an 11:1 comp ratio.He does'nt have enough knowledge of turbo systems to do so.


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## DwightLooi (May 16, 2000)

*Re: Is 11.1 compression to high for turbo?? (killa)*

quote:[HR][/HR]
Dwight, very well written, but you can still time the intake cam and the exhaust at different times like the "regular" DOHC" motors, kent cams makes adjustable chain gears for our cars.
Paul[HR][/HR]​I wasn't aware of that. The last time I was personally involved with a 16v VW was with an 87 16v 1.8 GTi six years ago. At that time, I did not come across adjustable internal chain sprockets only a single adjustable external sprocket. This allows advancing or retarding both cams in unison, but you cannot change the position of the camshafts in relation to each other. Nevertheless, it helps index those cams optimally -- a lot of times relying on the alignment notch on the cams, aftermarket or OEM, often means poor indexing. Proper indexing was worth 8 whp to me and I was on stock cams.* *In anycase, should they have been available, it'll still be be a big pain to use the adjustable intermediate chain sprockets.* Imagine that in between dyno pulls, you have to remove the intake runners and valve cover, spew oil all over the place to make an adjustment. You then have to put it all back, dyno, and repeat the process several times!
*That GTi was quite stock. Apart from the adjustable cam sprocket and dynoed cam & spark indexing, it had a Jacobs Ignition box, a signal conditioner for additional fuel enrichment at higher rpms (the 16v tended to lean out and go weak at higher rpms), a gutted n cut up factory filter box, a Random Tech cat and a tectonics catback. Otherwise the drive train is stock. It made 128 whp not shabby at all the way I looked at it. Everything else was stock on the car down to the suspension and BBS wheels. It had Ferrodo fast road pads and 195/50 ZR15 Dunlop SP Sport8000s, but that was it even the god damned radio was stock! Still, it was a good drivers car...
























[Modified by DwightLooi, 11:14 PM 8-20-2002]


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## Apeon (Aug 21, 2002)

*Re: Is 11.1 compression to high for turbo?? (DwightLooi)*

All those parts and effort and only 128hp? That is sad! I thought the 16v made 120 or 130 horsepower stock anyway. better to just get a 1.8T and chip it, or spend all that money for a decent stereo, amp, speakers, and subs.


[Modified by Apeon, 10:05 PM 8-21-2002]


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## turbo4dr8v (Dec 7, 2001)

*Re: Is 11.1 compression to high for turbo?? (Apeon)*

yes, too high


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## nabilsx (Jun 8, 2000)

*Re: Is 11.1 compression to high for turbo?? (Apeon)*

thats 128whp the 9A engine made 123 Chp "thats crank horse power" to have whp u get chp*0.15 "which is average friction and drive train loss etc.." and u get whp.
the european 2.0 16v ABF engine made 150 crank hp stock.


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (nabilsx)*

the 9A was actually 134hp and the PL 123.
Dwight, those internal cam gear are a pain the the behind to tune, i dont personally know of anyone who runs them, but still an option for those who got the time/money.
Paul


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## Vdublin (Nov 18, 2000)

*Re: Is 11.1 compression to high for turbo?? (killa)*

can someone explain to me compression. i dont know EVERYTHING about it. just the numbers part.


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## 1QUIKVR (Dec 7, 2001)

*Re: Is 11.1 compression to high for turbo?? (team~bunny)*

quote:[HR][/HR]I have 11.1 compression and a friend of mine who is a mechanic said that he would not put a turbo on it because of the high compression, what do you turbo guys think?? keep In mind i still want reliablity out of my car as well as speed. I have a turbo and intercooler off of a eagle talon, what do you think about that? thanks 

[Modified by team~bunny, 6:38 AM 8-19-2002][HR][/HR]​
if you can keep the intake charge below 200 degrees you can boost all you want(also high enough octane fuel) untill the head comes off that is


[Modified by BrandonVR6, 10:03 PM 8-22-2002]


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## killa (Nov 26, 2000)

*Re: Is 11.1 compression to high for turbo?? (BrandonVR6)*

yo, S&L boysssssssssssssssssssssss.
did i meet you at waterfest too?


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## DwightLooi (May 16, 2000)

*Re: Is 11.1 compression to high for turbo?? (Vdublin)*

quote:[HR][/HR]can someone explain to me compression. i dont know EVERYTHING about it. just the numbers part.[HR][/HR]​Are you kidding?
Anyway, compression normally refers to static compression. This refers to how much the air is squished by the pistons themselves. In a 2000cc engine, the pistons going from bottom to top will sweep up 500cc. If the space form by the piston top and the inner surface of the head (the combustion chamber) is 50cc, then you are pushing a total of 550cc into 50cc. That is 11:1 compression. Of course if you make the chamber bigger, like take some material of the top of the piston or shorten the connecting rod slightly or whatever, and make the chamber 55cc in volume at the top of the stroke, the you are pushing 555 cc into 55 cc or roughly 10.1:1.


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## Vdublin (Nov 18, 2000)

*Re: Is 11.1 compression to high for turbo?? (BrandonVR6)*

what do the numbers mean


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## need_a_VR6 (May 19, 1999)

*Re: Is 11.1 compression to high for turbo?? (Vdublin)*

quote:[HR][/HR]what do the numbers mean[HR][/HR]​Oi. It's the ratio of how much air you start out with in the cyl with the piston at the bottom, to what you have left when it's at the top. Think about it, compression ratio.


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