Really good Boost question.
09-21-2007, 10:38 PM
#1
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Really good Boost question. Ok guys I have read alot of usefull stuff on here but one question that I have never read about is. Is it better to run less compression more boost or more compression less boost. Keep in mind I am interested on pump gas 93 octane? 
09-21-2007, 10:57 PM
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il take a stab at this, it depends on your application. if you have a street car you are going to want torque down low so you can putt around so your gonna want to have a lil higher compression like 9.25 or so. this will allow you to keep some power on hand w/o getting into boost as much it at any.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
im sure some people will argue the difference in power output but my personally i would rather have the slightly higher compression (all forged of course) and less boost like i do now (9.25:1) for the fact that il have power w/o boost unlike the honda guys who have to rev the crap out of their motors to get into boost and to make power/torque. its about static compression.
im sure that Dr.turbo or someone will get on here and really go into detail. my examples are w/o the specifics and what not.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
im sure some people will argue the difference in power output but my personally i would rather have the slightly higher compression (all forged of course) and less boost like i do now (9.25:1) for the fact that il have power w/o boost unlike the honda guys who have to rev the crap out of their motors to get into boost and to make power/torque. its about static compression.
im sure that Dr.turbo or someone will get on here and really go into detail. my examples are w/o the specifics and what not.
Last edited by Firechicken1995; 09-21-2007 at 11:05 PM.
09-21-2007, 10:59 PM
#4
Originally Posted by Firechicken1995
il take a stab at this, it depends on your application. if you have a street car you are going to want torque down low so you can putt around so your gonna want to have a lil higher compression like 9.25 or so. this will allow you to keep some power on hand w/o getting into boost as much it at any.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
im sure some people will argue the difference in power output but my personally i would rather have the slightly higher compression (all forged of course) and less boost like i do now (9.25:1) for the fact that il have power w/o boost unlike the honda guys who have to rev the crap out of their motors to get into boost and to make power/torque.
im sure that Dr.turbo or someone will get on here and really go into detail. my examples are w/o the specifics and what not.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
im sure some people will argue the difference in power output but my personally i would rather have the slightly higher compression (all forged of course) and less boost like i do now (9.25:1) for the fact that il have power w/o boost unlike the honda guys who have to rev the crap out of their motors to get into boost and to make power/torque.
im sure that Dr.turbo or someone will get on here and really go into detail. my examples are w/o the specifics and what not.
I would have to agree with you on that also! Actually make's alot of sense.
09-22-2007, 08:11 PM
#6
Originally Posted by Firechicken1995
il take a stab at this, it depends on your application. if you have a street car you are going to want torque down low so you can putt around so your gonna want to have a lil higher compression like 9.25 or so. this will allow you to keep some power on hand w/o getting into boost as much it at any.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
if you have a race only car you are not going to be all too concerned about part throttle driving like a street car putting around town. you can go with lower compression and lose a lil torque dont low but it dont matter b/c at the track you are either all or nothing most of the time. so you can run lower compression and alot more boost.
I disagree.... most Race ONLY cars are seeing even more power gains with higher compression and High boost..... on Race gas all the time that is....
Quite a few of the 10.5 Outlaw guys i know run higher then 10:1 comp.
Im running a full point higher then what i did in my last motor.
Kyle
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09-22-2007, 11:22 PM
#9
Ive been wondering this as well so nice thread! Like same motor and FI combo, one on higher CR with 9-10 psi we'll say and pump vs a lower CR on 14 psi or so making roughly the same power. You would think the higher CR and lower boost would be safer due to less boost but i have no idea. Im keeping posted here as i will need a motor soon!
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09-23-2007, 08:40 AM
#11
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Maybe because the topic has been covered many times before.
Both ways can achieve results, but it depends how far you want to push things.
opting for lower compression, is by far the safer of the two methods.
And given you havent indicated what sort of power you want to achieve, giving you a direct answer is almost impossible.
Both ways can achieve results, but it depends how far you want to push things.
opting for lower compression, is by far the safer of the two methods.
And given you havent indicated what sort of power you want to achieve, giving you a direct answer is almost impossible.
09-23-2007, 10:06 AM
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and once again im retarded. ok kyle thats on a race car so give us the rundown on the street car in general. not to be a smart *** at all, i know you are pretty much a badass with your car and i know you have more knowledge than me. BTW you car is my hero.
Originally Posted by NA$TY-TA
I disagree.... most Race ONLY cars are seeing even more power gains with higher compression and High boost..... on Race gas all the time that is....
Quite a few of the 10.5 Outlaw guys i know run higher then 10:1 comp.
Im running a full point higher then what i did in my last motor.
Kyle
Quite a few of the 10.5 Outlaw guys i know run higher then 10:1 comp.
Im running a full point higher then what i did in my last motor.
Kyle
09-23-2007, 10:08 AM
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most of the folks I know would say a good all around combo is
9:1 and at least 8 psi. on V8 engines. The dude who helps me out' will not turbo an engine under 8 Psi he just says most engines will really come to life with 8 psi.
9:1 and at least 8 psi. on V8 engines. The dude who helps me out' will not turbo an engine under 8 Psi he just says most engines will really come to life with 8 psi.
09-23-2007, 11:27 AM
#16
Here found it, hope this helps you. I had my engine builder rip apart the blosk 2-3 times. I went back and forth from 8.5 to 9.5 a couple times, LOL. Good thing he's a good guy but I never even knew he was at that stage yet.
Anyways, I chose 8.5 so I could get the most out of pump gas plus I have shitty 91 here. I also have meth but don't want to reply on it all the time. Especially a pump failure under boost, etc. When I go to the track I can turn up the boost and turn on the meth. Good thread here, I got my answer....
https://ls1tech.com/forums/forced-induction/783603-high-static-compression-forced-induction.html
Anyways, I chose 8.5 so I could get the most out of pump gas plus I have shitty 91 here. I also have meth but don't want to reply on it all the time. Especially a pump failure under boost, etc. When I go to the track I can turn up the boost and turn on the meth. Good thread here, I got my answer....
https://ls1tech.com/forums/forced-induction/783603-high-static-compression-forced-induction.html
09-23-2007, 11:46 AM
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check out the EPP build thread with the APS firehawk. Made 700+ with 11:1 compression. APS twins and a 400+ci motor (with intercooler and meth on top of course). Runs 9psi. Very nice setup, I think that would be great for low end grunt (not like the 408 doesnt already have that anyway though.)
Im at 9.5:1 and low end torque is still strong with the cam and 346 in terms of daily driving. I currently run 5psi and plan to run 8psi next month once I fix a few things.
Im at 9.5:1 and low end torque is still strong with the cam and 346 in terms of daily driving. I currently run 5psi and plan to run 8psi next month once I fix a few things.
09-23-2007, 11:57 AM
#18
Originally Posted by Firechicken1995
and once again im retarded. ok kyle thats on a race car so give us the rundown on the street car in general. not to be a smart *** at all, i know you are pretty much a badass with your car and i know you have more knowledge than me. BTW you car is my hero.
For a street car only running pump 93 id stick around 8.5:1
The reason i say that is detination when u try and push it on pump gas.
Before when i was running under 9:1 i could get to about 15-16 psi on pump before id start to pick up some detination....
Now i was running a lil more timing then most..... i would never change it from pump to Race....
If you are wanting to push it harder on Pump id invest in a Meth kit.
Alot of good info in that other thread.
Kyle