b18a/b HIGH COMPRESSION?

Well, my father asked a one of his friends that used to race and had a DA, his friend said that the engine’s compression is too high, i was like whoa, i read that the 9.2:1 compression is ideal for boost, but really im not an expert on what is high or perfect for boost. Now here’s the question… is the compression high enough to do any changes before you get boosted or should i get the stainless steel headgasket, or look into some aftermarket pistons for low compression… You guys tell me…

the compression is just fine. the only bad thing is that they are cast iron pistons. for high boost ull want something forged. rods/pistons… stock pistons and rods should be good for about 300 whp

The compression ratio on the DA LS motors is 9.2:1 which is fine for FI. Whether you need to rebuild with strong internals depends on what your goals are.

stock sleeves on boosted ls is like 9:1 or 9.2:1 forged.
sleeved u can go to 10.6:1 on about 18-20 psi.

stock pistons/rods are weak, and if u dare to make 300 on them, ur balls are a HELL of a lot bigger than mine are. i dont like to boost over 7.

:iagree: your right, ill be boosted only six until i get money in the summer

Where are you pulling these random CR’s and boost levels from??? People boost B18C’s and B16’s all of the time on stock sleeves, and their CR is higher than 9.2:1. Sleeving the block has nothing to do with what CR you can run. You generally want a lower CR because it is less likely to detonate, especially running on pump gas. And I don’t know where the magical number of 18-21 psi on a sleeved block came from. 18 psi on a t25 or 18 psi on a gt42r? I run 10 psi daily on my 14b and am bumping up to 14 as soon as I get a new map sensor and time to tune. My new built motor is going to run near 30 psi on a gt30r.

Stop feeding people false information! An engines limitations are power, not a boost level. And when tuned properly, our motors can do a lot. Go drive around with your 7 psi and keep telling people it will blow up if you run any higher.

i am pulling them from motors i have built.

I have a guy in my car club that has been runnin 10.6:1 on sleeved 18-20 psi with a milled head and mls gasket. 467 whp on a mustang dyno, ls/vtec/turbo for 40,000 miles.

Also, judging by his post, not knowing his pistons/rods are like twigs, he doesnt know about any fuel management for his motor.

run ur low comp pistons up to 30 psi. Have fun with it. U can daily drive ur car at 100 psi for all i care. i drive 5 psi boost control 11 psi on dual basemaps, tuned by j-k-tuning. He also tunes all of the whiplashDVD cars.

and no, i dont give a shit how many psi u can run on a puss turbo. The sleeved number is on a Turbonectics t3/t4 60/63 60 trim w/ stage 5 wheel. The pistons + rods build psi is from a t3/t4 57 trim garrett.

and no, engine limitations are not power. The turbo limitations are power. good luck making power on ur 14b at 30 psi…good luck at 14 psi, shit u wont even make 300 at 14 psi.

Who made up these numbers that you can run? As far as I know, there aren’t published numbers for how much boost you can run on every motor. I also never said you can’t run high compression, but you made it sound like 18-21psi was the MAX that you can run on a sleeved block. If that’s not what you meant, then I apologize, that’s just the way it came across when I read it. And why do you say “run my low compression pistons at 30 psi and have fun with it”? What does that even mean? Are you saying that it’s bad to run low boost and high compression?

You can call it a puss turbo all you want, you’re just proving that you’re not grasping the concept I was trying to explain to this guy. My whole point is that you shouldn’t be saying that “A stock LS can only run x amount of boost”. That statement pretty much says nothing. The motor has a power limit, which from experience is around 300 whp, then rods start going. I thought you understood that when you made the comment about not pushing 300, but then you followed it up with a statement about not going over 7psi.

EDIT: Since you seem to be making a new post everytime I try to reply. Engine limitations most definitely ARE power, not a boost level. And if you actually read my post, you would see that I plan on running 30 psi on a gt30r, not the 14b. Go back and read. If you don’t think an engine’s limitations are power, then you have hundreds of pages to read on here and honda-tech that will explain that to you. And find for me where I said I’d make 300 at 14 psi, please. I only plan to make around 225. You are damn good at making shit up.

And for good measure, a turbo’s limitation are flow. Is there a horsepower axis on a compressor map? Granted, flow can be calculated into horsepower, it is still not the same.

lol, well ur first mistake is gettin info off of Honda-tech.

i am gettin those numbers from my expereinces. i have built engines and i have seen similar engines blow. The sleeved Ls/vtec/turbo blew up at 25 psi. that is why i say keep it lower. Generally things go wrong past 15-16 psi on a rods/pistons build. I dont even give a damn how many psi it takes with a turbo that doesnt make power past 5500.

All of the numbers are with a t3/t04e 57-60 trim. I am picking up a new turbo this weekend, Turbonectics t3/t04e 60 trim, stage 5 wheel. i want something to handle the H that will be goin in!!!

i get headaches reading this shit. run any compression you want, boost as high as you want, just make sure your car is in good shape and has been properly tuned.

I agree with Krazy. Tuning is important.

hey compton… my mom’s got a supercharged lawnmower, and she wants to know how much boost she can run on 5w-30 race oil. what do you think?
:stfu: