boosted high compression
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From: Margaritaville
Re: (Barney Ruble)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Barney Ruble »</TD></TR><TR><TD CLASS="quote">If high compression was so good then why does every other factory turbocharged vehicle have somewhat low compression 8:1-9:1 not 10 or 10.5 ?????? 
</TD></TR></TABLE>
Off the top of my head I know that the new 450hp Porsche Cayenne has 9.5:1 C/R.
</TD></TR></TABLE>Off the top of my head I know that the new 450hp Porsche Cayenne has 9.5:1 C/R.
Re: (RyanCivic2000)
high compression works good for me, but for most people i suggest 9.5:1 pistons. when things are said and done you'll be between 9.5:1 and 10:1, which is a perfect balance imo.
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well here's my 0.2 cents
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice
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From: Come to the, DarkSide
Re: (useless)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by useless »</TD></TR><TR><TD CLASS="quote">well here's my 0.2 cents
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice</TD></TR></TABLE>
so are you saying you should have stayed with the stock compression?
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice</TD></TR></TABLE>
so are you saying you should have stayed with the stock compression?
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From: 1989 HF CRX
Re: (Soon_2b_evil)
Well to comment on the high vs low compression and turbos...i had a nice long post, which featured some experienced guys sheading some light. And when it all ended. For maximum power, and least strain, low compression. And yes, in cases lower than 9.0:1.
Personal thought, i don't want my turbo to spool before 4,000rpm...i want to be able to cruise and not burn my fuel on one trip to school, and i want my engine to have some peace of mind every now and then, not high boosted pressure everytime i turn it on.
If your interested, its a good read.
High Compression Low Boost -- VS -- Low Compression High Boost ( 1 2 3 4 )
Personal thought, i don't want my turbo to spool before 4,000rpm...i want to be able to cruise and not burn my fuel on one trip to school, and i want my engine to have some peace of mind every now and then, not high boosted pressure everytime i turn it on.
If your interested, its a good read.
High Compression Low Boost -- VS -- Low Compression High Boost ( 1 2 3 4 )
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From: Chattanooga, TN
Re: (issues4)
thanks man thats real good i think i made the final decision of runing 9.5 cr i would like to run 15psi daily but i would like to be fully spooled bye at LEAST 4500 hopefully 4000 but i have alot more research to do before that will become a reality
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Re: (useless)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by useless »</TD></TR><TR><TD CLASS="quote">well here's my 0.2 cents
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice</TD></TR></TABLE>
More boost means a faster impeller speed, and a faster impeller speed means it takes more exhaust energy and more RPM's to spool the turbo. You got used to the power with 7 psi, so dropping the compression you might have seen a 5 WHP loss, not a big deal, but then when you add more boost it seems to take longer for it to get going.
The tune has a bigger effect on how long it takes for the turbo to spool that a 1 point difference in compression does. A lean tune before boost with not a whole lot of timing will produce much higher EGT's than a very fat tune with a bunch of timing in it. Higher EGT's means the turbo will spool quicker.
Personally, I would love to see somebody take a motor out to 81.5MM and throw in some 9:1 JE's, break the motor in on a dyno, then dyno it and datalog. Pull out the 9:1 JE's, throw in some 9.8:1 or 10:1 or 10.5:1 JE's, break it in the same way, then dyno it and datalog it again. I'd enjoy the results, and probably the excuses made by the high compression crowed.
last year i ran my civic with a stock b16 w/hondata at 7psi and it felt great. i built the engine with 9.0.1 c/r and now boosting 11psi in all from 7psi to 11psi i gained 40 whp but now i find it sucks i only get 11psi when the vtec comes on so pretty much 5000rpm. i hate the car now. i should of read more from you guys before making a choice</TD></TR></TABLE>
More boost means a faster impeller speed, and a faster impeller speed means it takes more exhaust energy and more RPM's to spool the turbo. You got used to the power with 7 psi, so dropping the compression you might have seen a 5 WHP loss, not a big deal, but then when you add more boost it seems to take longer for it to get going.
The tune has a bigger effect on how long it takes for the turbo to spool that a 1 point difference in compression does. A lean tune before boost with not a whole lot of timing will produce much higher EGT's than a very fat tune with a bunch of timing in it. Higher EGT's means the turbo will spool quicker.
Personally, I would love to see somebody take a motor out to 81.5MM and throw in some 9:1 JE's, break the motor in on a dyno, then dyno it and datalog. Pull out the 9:1 JE's, throw in some 9.8:1 or 10:1 or 10.5:1 JE's, break it in the same way, then dyno it and datalog it again. I'd enjoy the results, and probably the excuses made by the high compression crowed.
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From: Norway
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">
Higher EGT's means the turbo will spool quicker.</TD></TR></TABLE>
I was under the impression that it was the mass/momentum/speed/kinetic energy of the exhaust that spun the turbine wheel? And that temperatures were not all that important?
Higher EGT's means the turbo will spool quicker.</TD></TR></TABLE>
I was under the impression that it was the mass/momentum/speed/kinetic energy of the exhaust that spun the turbine wheel? And that temperatures were not all that important?
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From: dirty south
Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">
If the engine is built with the right parts, methods, tools, specs, and tolerances there is ABSOLUTELY NO reason it shouldn't be as good or BETTER than a factory Honda engine. If you can't build a better engine than what comes stock from Honda, why build?</TD></TR></TABLE>
Because your building for high horsepower application plus your building a stronger engine when I say factory built I'm talking about reliability and longevity you don't get those with a built engine. Do you know anyone with a built engine with over 100k, I don't ? I understand the concept behind building the engine don't get me wrong but everyone and their mom seems to have an import shop and claims to build a good engine not true. Yes if you have the correct tools it should in
theory last as long but does it ? Honda's engine weren't meant to be turbocharged so anyone thinking they can have a built 500hp engine for any length of time is wrong 1-2yrs (In my opinion) I don't think people really consider that when they sell the farm and build the monster only to have some kind of problem within a 1 yr or 2 and have to do it all over again
If the engine is built with the right parts, methods, tools, specs, and tolerances there is ABSOLUTELY NO reason it shouldn't be as good or BETTER than a factory Honda engine. If you can't build a better engine than what comes stock from Honda, why build?</TD></TR></TABLE>
Because your building for high horsepower application plus your building a stronger engine when I say factory built I'm talking about reliability and longevity you don't get those with a built engine. Do you know anyone with a built engine with over 100k, I don't ? I understand the concept behind building the engine don't get me wrong but everyone and their mom seems to have an import shop and claims to build a good engine not true. Yes if you have the correct tools it should in
theory last as long but does it ? Honda's engine weren't meant to be turbocharged so anyone thinking they can have a built 500hp engine for any length of time is wrong 1-2yrs (In my opinion) I don't think people really consider that when they sell the farm and build the monster only to have some kind of problem within a 1 yr or 2 and have to do it all over again
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From: dirty south
Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">
Off the top of my head I know that the new 450hp Porsche Cayenne has 9.5:1 C/R.
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okay the key word here is PORSCHE you do realize that vehicle you mentioned is a SUV with V8 right...............
plus Porsche turbo cars have years of R&D they should be able to do that you have to be kidding. You can't compare the two a $4k honda engine to whatever Porsche puts in their cars please.
Off the top of my head I know that the new 450hp Porsche Cayenne has 9.5:1 C/R.
</TD></TR></TABLE>
okay the key word here is PORSCHE you do realize that vehicle you mentioned is a SUV with V8 right...............
plus Porsche turbo cars have years of R&D they should be able to do that you have to be kidding. You can't compare the two a $4k honda engine to whatever Porsche puts in their cars please. 
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From: Worcester, MA, USA
Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">If the engine is built with the right parts, methods, tools, specs, and tolerances there is ABSOLUTELY NO reason it shouldn't be as good or BETTER than a factory Honda engine. If you can't build a better engine than what comes stock from Honda, why build?</TD></TR></TABLE>
Engines that are going to be boosted require different tolerances than naturally aspirated engines. The pistons need to have more clearance, for example, because they will expand more given the heat of the combustion. The larger piston clearance can lead to scuffed cylinder walls, however, since the pistons aren't always hot.
Engines that are going to be boosted require different tolerances than naturally aspirated engines. The pistons need to have more clearance, for example, because they will expand more given the heat of the combustion. The larger piston clearance can lead to scuffed cylinder walls, however, since the pistons aren't always hot.
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Re: (Barney Ruble)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Barney Ruble »</TD></TR><TR><TD CLASS="quote">If high compression was so good then why does every other factory turbocharged vehicle have somewhat low compression 8:1-9:1 not 10 or 10.5 ?????? </TD></TR></TABLE>
For NA applications, the use of more intake cam duration improves VE but hurts effective compression thus one can compensate for the loss of effective compression by raising static compression. Thus, the only benefit from raising static compression is to allow more intake duration to raise VE. It is impossible to increase thermal efficiency by raising compression unless race fuel is used.
Since factory cars must pass emissions and idle acceptably, their cam profiles must be reasonable and corresponding CR is rather low, but with the advent of variable cam timing, CR could be raised to take advantage of the increase in intake duration. Because factory turbocharged cars do not necessarily need more intake duration to increase VE (as the turbo does this job) CR can remain low and effective compression will remain unchanged.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Oyvind Ryeng »</TD></TR><TR><TD CLASS="quote">
I was under the impression that it was the mass/momentum/speed/kinetic energy of the exhaust that spun the turbine wheel? And that temperatures were not all that important?</TD></TR></TABLE>
The impression you are under is a correct one. Higher temps from retarded ignition timing will increase lag.
</TD></TR></TABLE>For NA applications, the use of more intake cam duration improves VE but hurts effective compression thus one can compensate for the loss of effective compression by raising static compression. Thus, the only benefit from raising static compression is to allow more intake duration to raise VE. It is impossible to increase thermal efficiency by raising compression unless race fuel is used.
Since factory cars must pass emissions and idle acceptably, their cam profiles must be reasonable and corresponding CR is rather low, but with the advent of variable cam timing, CR could be raised to take advantage of the increase in intake duration. Because factory turbocharged cars do not necessarily need more intake duration to increase VE (as the turbo does this job) CR can remain low and effective compression will remain unchanged.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Oyvind Ryeng »</TD></TR><TR><TD CLASS="quote">
I was under the impression that it was the mass/momentum/speed/kinetic energy of the exhaust that spun the turbine wheel? And that temperatures were not all that important?</TD></TR></TABLE>
The impression you are under is a correct one. Higher temps from retarded ignition timing will increase lag.
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From: Margaritaville
Re: (ShapeGSX)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ShapeGSX »</TD></TR><TR><TD CLASS="quote">
Engines that are going to be boosted require different tolerances than naturally aspirated engines. The pistons need to have more clearance, for example, because they will expand more given the heat of the combustion. The larger piston clearance can lead to scuffed cylinder walls, however, since the pistons aren't always hot.</TD></TR></TABLE>
Correct, boosted applications do require looser tolerances than N/A engines, but you have to keep in mind the factory Honda engines have lasted over 300,000 miles. Slightly looser tolerances are not going to hurt reliablity that much. The reason these built engines won't last for such high mileage is that the people that are building them are planning on putting 400+whp down with these engines. If the built engine was driven N/A at a moderate hp level for 10 years, I bet it would be 98% as reliable as a factory engine.
Engines that are going to be boosted require different tolerances than naturally aspirated engines. The pistons need to have more clearance, for example, because they will expand more given the heat of the combustion. The larger piston clearance can lead to scuffed cylinder walls, however, since the pistons aren't always hot.</TD></TR></TABLE>
Correct, boosted applications do require looser tolerances than N/A engines, but you have to keep in mind the factory Honda engines have lasted over 300,000 miles. Slightly looser tolerances are not going to hurt reliablity that much. The reason these built engines won't last for such high mileage is that the people that are building them are planning on putting 400+whp down with these engines. If the built engine was driven N/A at a moderate hp level for 10 years, I bet it would be 98% as reliable as a factory engine.
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Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">Anything under 9:1 C/R is just too low, IMO.</TD></TR></TABLE>
Finally someone that agrees with me.. I would try to stay above 9.4:1 but thats just me..
Finally someone that agrees with me.. I would try to stay above 9.4:1 but thats just me..
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Re: (tgreaves)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tgreaves »</TD></TR><TR><TD CLASS="quote">
Finally someone that agrees with me.. I would try to stay above 9.4:1 but thats just me..</TD></TR></TABLE>
I bet you'd notice the difference between 9.4:1 and 9:1, right?
Finally someone that agrees with me.. I would try to stay above 9.4:1 but thats just me..</TD></TR></TABLE>
I bet you'd notice the difference between 9.4:1 and 9:1, right?
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From: Margaritaville
Re: (b16coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">
I bet you'd notice the difference between 9.4:1 and 9:1, right?</TD></TR></TABLE>
I noticed a big difference between 9.6:1 and 10:1.
I bet you'd notice the difference between 9.4:1 and 9:1, right?</TD></TR></TABLE>
I noticed a big difference between 9.6:1 and 10:1.
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Re: (b16coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">
I bet you'd notice the difference between 9.4:1 and 9:1, right?</TD></TR></TABLE>
Going from 9:1 to 9.5:1... Yes you would and it would make a difference on tuning also..
I bet you'd notice the difference between 9.4:1 and 9:1, right?</TD></TR></TABLE>
Going from 9:1 to 9.5:1... Yes you would and it would make a difference on tuning also..
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Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">
I noticed a big difference between 9.6:1 and 10:1.</TD></TR></TABLE>
10 bucks says it's all in your head. You know you bumped up compression, so you think you feel it SOTP. God, weather alone between 2 days can have a bigger effect on the power output of your car, so how you can you say a .4 increase in compression was a BIG difference? That's like 4-5 horsepower, with all other variables being equal.
I noticed a big difference between 9.6:1 and 10:1.</TD></TR></TABLE>
10 bucks says it's all in your head. You know you bumped up compression, so you think you feel it SOTP. God, weather alone between 2 days can have a bigger effect on the power output of your car, so how you can you say a .4 increase in compression was a BIG difference? That's like 4-5 horsepower, with all other variables being equal.
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From: Margaritaville
Re: (b16coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">
10 bucks says it's all in your head. You know you bumped up compression, so you think you feel it SOTP. God, weather alone between 2 days can have a bigger effect on the power output of your car, so how you can you say a .4 increase in compression was a BIG difference? That's like 4-5 horsepower, with all other variables being equal.</TD></TR></TABLE>
Actually the dyno showed a 20whp increase and even more torque with better curves.
10 bucks says it's all in your head. You know you bumped up compression, so you think you feel it SOTP. God, weather alone between 2 days can have a bigger effect on the power output of your car, so how you can you say a .4 increase in compression was a BIG difference? That's like 4-5 horsepower, with all other variables being equal.</TD></TR></TABLE>
Actually the dyno showed a 20whp increase and even more torque with better curves.
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Re: (RyanCivic2000)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RyanCivic2000 »</TD></TR><TR><TD CLASS="quote">
Actually the dyno showed a 20whp increase and even more torque with better curves.</TD></TR></TABLE>
20 WHP from just .4 tenths of a point in compression, bullshit. That little compression does not make that much of a difference unless something else is changed.
Actually the dyno showed a 20whp increase and even more torque with better curves.</TD></TR></TABLE>
20 WHP from just .4 tenths of a point in compression, bullshit. That little compression does not make that much of a difference unless something else is changed.
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From: Margaritaville
Re: (b16coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">20 WHP from just .4 tenths of a point in compression, bullshit. That little compression does not make that much of a difference unless something else is changed.</TD></TR></TABLE>
Well, you're wrong. The only other variables were a .020 overbore and Eagle Rods.
Well, you're wrong. The only other variables were a .020 overbore and Eagle Rods.
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Re: (b16coupe)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b16coupe »</TD></TR><TR><TD CLASS="quote">
20 WHP from just .4 tenths of a point in compression, bullshit. That little compression does not make that much of a difference unless something else is changed.</TD></TR></TABLE>
On a FI motor this is very possible..
20 WHP from just .4 tenths of a point in compression, bullshit. That little compression does not make that much of a difference unless something else is changed.</TD></TR></TABLE>
On a FI motor this is very possible..
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From: Margaritaville
Re: (tgreaves)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tgreaves »</TD></TR><TR><TD CLASS="quote">
On a FI motor this is very possible..</TD></TR></TABLE>
The motor was actually N/A at the time.
On a FI motor this is very possible..</TD></TR></TABLE>
The motor was actually N/A at the time.
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From: Baltimore, MD, USA
Re: (RyanCivic2000)
well my buddy blow his motor and it was 10:1 and he dropped it to 8:5.1 and you do notice the difference. its a LOT slower off of boost and a longer spool up time.
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