Why can't we raise the boost?
Thread Starter
On The Tree
Joined: Feb 2004
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From: Daytona Beach, FL
Why can't we raise the boost? I have a question, and I hope I don't sound too dumb. How come a guy with an eclipse turbo, can upgrade his fuel system and what not, and put on a big turbo, and set the boost to like 15 or 18, and Ls1's can only do like 6 or 8? what's needed to be done to an ls1 to run on high boost? or are these engines aren't made for that kinda boost? thanks in advance. I am just learning, so no flamming....unless nesecessary lol!
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Joined: Dec 2001
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From: Columbia, MD
Originally Posted by themindfield
I have a question, and I hope I don't sound too dumb. How come a guy with an eclipse turbo, can upgrade his fuel system and what not, and put on a big turbo, and set the boost to like 15 or 18, and Ls1's can only do like 6 or 8? what's needed to be done to an ls1 to run on high boost? or are these engines aren't made for that kinda boost? thanks in advance. I am just learning, so no flamming....unless nesecessary lol!
Cars that come with turbochargers/superchargers from the factory already have motors built to handle boost. That's why you can generally crank up the boost on the cars you mentioned, without adverse effects. The same is true for the 2003/4 Cobra and the WRX Sti.
For us LS1 owners, we have to spend several thousand dollars to prep the motor to handle high boost, if we want the motor to last. Which is why most people just choose to leave the boost low, and save the motor.
Hope that helps.
Happy racing.
Thread Starter
On The Tree
Joined: Feb 2004
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From: Daytona Beach, FL
Crunch that was great. I am just wondering now, what is all needed to make an ls1 boost ready like an eclipse or a sti engine. what parts and roughly how much would it cost. Thanks in advance again!
Originally Posted by cablebandit
airflow.....ask how much air he is pumping with a smaller turbo at 15-20psi vs a t-76 at 8 psi.
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Verdad Gallardo Thread Starter
On The Tree
Joined: Feb 2004
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From: Daytona Beach, FL
ok, so let me get this straight, if one changes the pistons (i am guessing, to lower comp. ones), and different rods, and rod bolts. then we can boost 15 psi or what not?? oh i understand that we need to upgrade the fuel system as well. but I am just talking engine wise....thanks a lot.
we could go to 15 but not too much higher without head lifting issues. The eclipse 4g63t, motor has 6 or maybe 5 head bolts per cylinder. I dont remember right off hand
on the ls1 the heads pop off with too much pressure
it sucks, I wish I had gone with a stroker and nitrous now. but am too far into this to change at this point in time.
thanks
ed
firebird455@onebox.com
on the ls1 the heads pop off with too much pressure
it sucks, I wish I had gone with a stroker and nitrous now. but am too far into this to change at this point in time.
thanks
ed
firebird455@onebox.com
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Joined: Sep 2003
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From: "Tr"Asheville
Let me ask this, I'm building a 382 all bore iron block (6.0L block) engine with arp studs throughout and arp L19 rod bolts with a factory crank, eagle forged rods and haven't decided on the pistons yet but they will more than likely be coated forged pistons. Using ARP head studs and (which head gaskets cometics??) what kind of boost do you think I can safely run on this combo considering the head studs and the rest of the buildup?
-Sly
-Sly
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From: F.H,Waterford,Port Huron, MI
Just so you no 15psi of boost is just a number and can be different in different cars. Meaning a better flowing or colder air temp and the same "15psi" is more power! Don't go by boost number! As DI-sc with a 9psi pulley is better on a better built motor than stock but with the same pulley!
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From: "Tr"Asheville
Gotcha, I'm pretty new to the *boost* world so I'm trying to learn quickly because I blew the stock bottom end in my car this weekend and am in the process of buying everything to put together my new engine to handle a custom turbo setup. If you guys have the time can you either post here or pm me with what you know about turbo's such as what kind of cam's they like, exhaust etc... my current list of mods besides the new shortblock include....
PP Stage 3 LS6 heads (2.055/1.575)
230/236 .592/.578 114lsa +2 cam
1 3/4 LT's with 3in mandrel bent true duals all the way out the back
Ported LS6 intake, Ported TB and MAF, Ported LS6 oil pump
Hardened pushrods, yella terra rockers, asp pulley
Yank SS4000, 3.73 gears
and all the other little stuff to go along with everything, basically every other supporting mod.
Oh ya what size injectors would be required at these levels and will an in tank 255lph fuel pump be sufficient?
...Dang man sorry for hi-jacking the thread figured this will help you out too since you said your learning too
-Sly
P.S. Thanks for all the help guys!!!
PP Stage 3 LS6 heads (2.055/1.575)
230/236 .592/.578 114lsa +2 cam
1 3/4 LT's with 3in mandrel bent true duals all the way out the back
Ported LS6 intake, Ported TB and MAF, Ported LS6 oil pump
Hardened pushrods, yella terra rockers, asp pulley
Yank SS4000, 3.73 gears
and all the other little stuff to go along with everything, basically every other supporting mod.
Oh ya what size injectors would be required at these levels and will an in tank 255lph fuel pump be sufficient?
...Dang man sorry for hi-jacking the thread figured this will help you out too since you said your learning too
-Sly
P.S. Thanks for all the help guys!!!
Originally Posted by themindfield
I have a question, and I hope I don't sound too dumb. How come a guy with an eclipse turbo, can upgrade his fuel system and what not, and put on a big turbo, and set the boost to like 15 or 18, and Ls1's can only do like 6 or 8? what's needed to be done to an ls1 to run on high boost? or are these engines aren't made for that kinda boost? thanks in advance. I am just learning, so no flamming....unless nesecessary lol!
TECH Apprentice
Joined: Jan 2004
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From: Frisco TX (Dallas Area)
I don't mean to sound like and *** (but I will, don't make me 
), but boost psi is just a number that goes along with CR. PTV cearance and all the others. The idea for power is CFM airflow through the engine. The more through the engine, the more power potential.
Cylinder pressure makes power, period! If you have high CR, boost only can raise cylinder pressure so high without grenade results. Each engine is designed for a max cylinder pressure. This involves piston strength, head clamping force, bottom end strength and a lot of other things. Boost motors reduce CR to accommodate extra pressure in the cylinders. A little boost with high CR makes the same hp as a lot of boost with low CR for instance. The ability of the engine to ingest and expel gasses also makes a big difference in the amount of boost psi an engine can live with. A better exhaust with the same setup will REDUCE boost psi, but keep the same or get better hp numbers. Don't ask how much boost, ask how much CFM the combo can process! Just like N/A, think about head flow, exhaust flow and rpm range of the powerband. That'll give you the real answer. HTH
), but boost psi is just a number that goes along with CR. PTV cearance and all the others. The idea for power is CFM airflow through the engine. The more through the engine, the more power potential.Cylinder pressure makes power, period! If you have high CR, boost only can raise cylinder pressure so high without grenade results. Each engine is designed for a max cylinder pressure. This involves piston strength, head clamping force, bottom end strength and a lot of other things. Boost motors reduce CR to accommodate extra pressure in the cylinders. A little boost with high CR makes the same hp as a lot of boost with low CR for instance. The ability of the engine to ingest and expel gasses also makes a big difference in the amount of boost psi an engine can live with. A better exhaust with the same setup will REDUCE boost psi, but keep the same or get better hp numbers. Don't ask how much boost, ask how much CFM the combo can process! Just like N/A, think about head flow, exhaust flow and rpm range of the powerband. That'll give you the real answer. HTH
Thread Starter
On The Tree
Joined: Feb 2004
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From: Daytona Beach, FL
well Assassin, before I say anything I want everyone to know that I am a BIG LS1 fan.
now, about HP of an eclipse. if you were to take let's say a 98 eclipse GSX. and put the normal boltons, upgrade the fuel system, slap on a turbo like a t3/t4 60-1, or even a tad smaller, like a 50 trim. you get some serious numbers, i mean 400 HP is on the low side for that turbo setup.
Part of the reason why they get these numbers is because these ******* push 18 - 25 PSI, with ease. I guess thats how these motors are built to work or something, I don't know. but if these guys were forced to push only like 8 psi or something like that, then ur right, their engine next to a stock ls1 is week.
I hope i didn't rub off as a dsmer....I don't want to get flammed!
now, about HP of an eclipse. if you were to take let's say a 98 eclipse GSX. and put the normal boltons, upgrade the fuel system, slap on a turbo like a t3/t4 60-1, or even a tad smaller, like a 50 trim. you get some serious numbers, i mean 400 HP is on the low side for that turbo setup.
Part of the reason why they get these numbers is because these ******* push 18 - 25 PSI, with ease. I guess thats how these motors are built to work or something, I don't know. but if these guys were forced to push only like 8 psi or something like that, then ur right, their engine next to a stock ls1 is week.
I hope i didn't rub off as a dsmer....I don't want to get flammed!
Originally Posted by 02BlueFirehawk
You are really pushing the limit with the stock-type aluminum heads with 20psi on the ls1. Raymer has shown this.
not sure how much boost he's pushing, but he's at 1150 crank HP with his 382 all aluminum ls1 (true ls1) with standard arp head studs and grafite gaskets.
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From: "Tr"Asheville
Originally Posted by TeeKay
A little boost with high CR makes the same hp as a lot of boost with low CR for instance.
-Sly