Coming soon
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1st Gear
Joined: Feb 2008
Posts: 297
From:
Coming soon
Well due to oil pump
failure the second part of
my engine upgrade is
under way the part list
this time : aeg crank and
83mm je pistons in 10:1
compression hopefully the
engine will last long
enough to make it to a
dyno
anyone know a easy
engine removal method
for quattro?
failure the second part of
my engine upgrade is
under way the part list
this time : aeg crank and
83mm je pistons in 10:1
compression hopefully the
engine will last long
enough to make it to a
dyno
anyone know a easy
engine removal method
for quattro?
I'm make believe
Joined: Dec 2006
Posts: 17,587
From: In my head
Who is crazy enough to run 10:1 on these cars..... hhmmm
Disp + compression = happiness.
You will probably have to pull it out the front like everyone else does. When my engine was removed it acutally went out the bottom. You still should be able to do that if you have a lift
Disp + compression = happiness.
You will probably have to pull it out the front like everyone else does. When my engine was removed it acutally went out the bottom. You still should be able to do that if you have a lift
2nd Gear
Joined: Oct 2007
Posts: 1,196
From: Over There
Who is crazy enough to run 10:1 on these cars..... hhmmm
Disp + compression = happiness.
You will probably have to pull it out the front like everyone else does. When my engine was removed it acutally went out the bottom. You still should be able to do that if you have a lift
Disp + compression = happiness.
You will probably have to pull it out the front like everyone else does. When my engine was removed it acutally went out the bottom. You still should be able to do that if you have a lift
I'm make believe
Joined: Dec 2006
Posts: 17,587
From: In my head
I have my stock 9.5:1 20mm stock pistons if you wanna throw in some new rods and do a rebuild 
They be goin cheap to
They be goin cheap to
2nd Gear
Joined: Mar 2006
Posts: 1,288
From: Chester/Sterling Forest, NY
awdterror
Higher compression DOES NOT spool the turbo quicker, period, amen. Mr. Evans tested a GSR, dropping from 10:1 to 9:1 compression resulted in 2-4 WHP off boost (not even noticeable) and about 12 peak WHP under boost. He posted the boost curve, the spool up is EXACTLY the same.
I'll take 9:1 compression and a buttload more boost for a street motor, thank you kindly. The benefits of lower compression outweight the downfalls.
http://www.boosted-hybrid.com/viewtopic.php?t=1612
There's the 10:1 vs. 9:1 post.
And finally, for what it's worth, if I were running some mondo huge turbo on my honda like a GT35R or a T3/T67 I would most certainly run 10:1 or 10.5:1 compression. 10.5:1 84MM LS/VTEC + T3/T67 will clear 400 WHP at 10, maybe 11 psi. Then when you add race gas into the mix you'll make a bit more peak horsepower than what the low comp setup would make.
Teach
All right, if you are really curious about what to run for a static and dynamic compression ratio, go to one of the manufacturer's websites. They will give recommendations for static compression usually with a chart for varying levels of boost and the resulting dynamic compression ratios.
As well they will have their recommendations for fuel octane requirements for the various ratios. If you go too high of a dynamic ratio, you will detonate severely and rattle the bottom end losing horsepower and ultimately destroying the main bearings.
If you are having trouble finding charts, BDS and Weiand offer this information for sure on their websites.
FYI anything above an 10:1 compression with a turbo or supercharger is normally reserved for alcohol injected engines.
And finally, Your performance will be much better with lower compression and higher boost.
Higher compression DOES NOT spool the turbo quicker, period, amen. Mr. Evans tested a GSR, dropping from 10:1 to 9:1 compression resulted in 2-4 WHP off boost (not even noticeable) and about 12 peak WHP under boost. He posted the boost curve, the spool up is EXACTLY the same.
I'll take 9:1 compression and a buttload more boost for a street motor, thank you kindly. The benefits of lower compression outweight the downfalls.
http://www.boosted-hybrid.com/viewtopic.php?t=1612
There's the 10:1 vs. 9:1 post.
And finally, for what it's worth, if I were running some mondo huge turbo on my honda like a GT35R or a T3/T67 I would most certainly run 10:1 or 10.5:1 compression. 10.5:1 84MM LS/VTEC + T3/T67 will clear 400 WHP at 10, maybe 11 psi. Then when you add race gas into the mix you'll make a bit more peak horsepower than what the low comp setup would make.
Teach
All right, if you are really curious about what to run for a static and dynamic compression ratio, go to one of the manufacturer's websites. They will give recommendations for static compression usually with a chart for varying levels of boost and the resulting dynamic compression ratios.
As well they will have their recommendations for fuel octane requirements for the various ratios. If you go too high of a dynamic ratio, you will detonate severely and rattle the bottom end losing horsepower and ultimately destroying the main bearings.
If you are having trouble finding charts, BDS and Weiand offer this information for sure on their websites.
FYI anything above an 10:1 compression with a turbo or supercharger is normally reserved for alcohol injected engines.
And finally, Your performance will be much better with lower compression and higher boost.
I'm make believe
Joined: Dec 2006
Posts: 17,587
From: In my head
Anyways, ill let turbobygarrett start
Generally, compression ratio should be set as high as feasible without encountering detonation at the maximum load condition. Compression ratio that is too low will result in an engine that is a bit sluggish in off-boost operation. However, if it is too high this can lead to serious knock-related engine problems.
Now if it was a race motor, i would rather run 8.5-9.0:1 since it will be in boost always and mixed with race fuel.
5th Gear
Joined: Sep 2005
Posts: 6,678
From: Colchester, VT
I didn't make up anything. I wanted to see if anyone was thinking for themselves, afterall, FACTS > followers.
As for the matter of increasing off-boost power/response, its at a sacrifice of the high end ON boost power. I haven't heard anyone mention anything about that, and my concern is that you say 'its not "I can", its "I DO"' which may be assuring enough for someone to do the same, and still treat it like they were building a 'top end' machine. There's a ton of talk on here every day about maxing out the potential of a turbo. Everybody wants to run as much boost as they can.
I'd rather not see someone throw a rod because they tried to push boost further than their CR should allow. THATS my issue here.
As for the matter of increasing off-boost power/response, its at a sacrifice of the high end ON boost power. I haven't heard anyone mention anything about that, and my concern is that you say 'its not "I can", its "I DO"' which may be assuring enough for someone to do the same, and still treat it like they were building a 'top end' machine. There's a ton of talk on here every day about maxing out the potential of a turbo. Everybody wants to run as much boost as they can.
I'd rather not see someone throw a rod because they tried to push boost further than their CR should allow. THATS my issue here.
I'm make believe
Joined: Dec 2006
Posts: 17,587
From: In my head
How are you sacraficing off boost power? You run less psi but the engine is making more power, they offset. You are also pushing the turbo less to make the power so you are closer to the center efficiency island of the turbo and getting lower temps out the turbo.
If someone wants top end power, more reason to increase compression since they will either be using a larger A/R or turbo all together. This would result in more lag where off boost power will be needed. Not to mention they can also add in cams to push the powerband where they want it.
If you havent noticed, no one actually maxes out anything. They put in one turbo and if it doesnt make enough power, they add in another one. There isnt enough people that actually max out a setup with a proper manifold and head work since they cost far more than a new $1200 turbo. Personally i think its stupid that people are running turbos capable of over 500whp to run 400whp with more of psi instead of actually adding the parts to make a 400whp turbo make 400whp.
A good tune will keep the engine detination from happening, and running to much boost would be octane dependent. Either way you did something extremely stupid if you blew anything up. 10:1 is safe to run on pump gas and there are tons of honda guys still running 10.5-11:1 with boost making well over 400 and 500whp.
I like having 10:1 and would be happy with 9.5:1. I dont think anyone should run less than 9:1 since you will suffer way to much engine response to run more psi on the street. If you rather have a low compression engine, thats your call. We are all allowed to have opinions
If someone wants top end power, more reason to increase compression since they will either be using a larger A/R or turbo all together. This would result in more lag where off boost power will be needed. Not to mention they can also add in cams to push the powerband where they want it.
If you havent noticed, no one actually maxes out anything. They put in one turbo and if it doesnt make enough power, they add in another one. There isnt enough people that actually max out a setup with a proper manifold and head work since they cost far more than a new $1200 turbo. Personally i think its stupid that people are running turbos capable of over 500whp to run 400whp with more of psi instead of actually adding the parts to make a 400whp turbo make 400whp.
A good tune will keep the engine detination from happening, and running to much boost would be octane dependent. Either way you did something extremely stupid if you blew anything up. 10:1 is safe to run on pump gas and there are tons of honda guys still running 10.5-11:1 with boost making well over 400 and 500whp.
I like having 10:1 and would be happy with 9.5:1. I dont think anyone should run less than 9:1 since you will suffer way to much engine response to run more psi on the street. If you rather have a low compression engine, thats your call. We are all allowed to have opinions
