Thread: Some more carnage on 10:1 motor during build.

well a long story short, i found out why the motor detonated at higher boost levels, for one it was cuz i wasnt using race gas, with the 100 octane in there it was perfect at 19psi boost, this motor loved boost, i did not know it was a 10:1 motor until i pulled the head off and took a look. kinda sucked in a way but thats why this motor was crazy strong, i think at the higher boost level on race gas this thing was putting out over 300wtq, it was insane from 3-5k rpms i bet the hp was close to or at least 280whp. This all on a T25 with S4 cams and many other mods that are in my sig, Well long story short i had some serious detonation when preparing for dyno day. 4th gear run from 2500-redline. 3-5k there was bad detonation after 5k it stopped as usual because i had been running it without race gas for a while but it was always high rpm runs.

Now i installed my new CP 9:1 pistons, oh soo shiney and look durable as hell. Interesting find i did a compression check on my motor because it was blowing hella air and smoke and oil out of my breather covering everything in my engine bay with oil residue, i knew what was up, i knew at least one set of ring lands was gone. Now heres the kicker.... did the compression check and here are the results

1: 105psi 2: 175psi 3: 175psi 4: 175psi.

That is freaking rediculous for this reason, pulled all the pistons out today and to my dismay i found every single sets of ringlands on every single piston being blown to bits. The motor still ran strong as hell for this problem and until the headgasket blew on me too. haha. The SR20 motor is freakin awsome. haha

The torque down low was gone because of this but high rpms was still pretty good. Now the motor will be bullet proof for what im going to do with it. Here are some pics and the interesting thing is that all the ringlands failed at the front side of the pistons closest to front of the block. #1 was the worst, it was shattered, take a look at the pics. haha











and here are some pics of the pretty new CP pistons, nice and perfect fit.





These are mated to stock rods being stock rods are known to go well over 550whp. i dont plan on ever going that high being this is my daily driver, i will upgrade turbo later after i attempt the t25 record and dyno. I will be going to around 350whp on around 14psi and 400whp at around 20psi. So i should be good to go. and hopefully i wont have any issues anymore for a long time, i will be using a cometic headgasket. Let me know what you guys think

Pistons look nice, I would've done rods too though. You don't need rods until you REALLY need them. The threat of not having rods in my S13 is the ONLY reason I have cranked the boost up. 300hp is only enough when you have 250. When you have 300 it's not enough Boost is like crack rock, no matter how much you have you always want more.

I also didn't see you mention aftermarket headstuds. Are they in the plans? A cometic HG only works as well as the studs holding it tight.

Kevlar edition SR20

just curious u say ur going for a T25 record, whats the record now on a DE??

i saw them pistons in person really pretty.... but can belive 175psi on 3 pistons with broken ring lands.. one strong sr20...... thanks to ashton i also have a 10:1 motor, thinking it was a 9:5:1 motor...haha..

no no headstuds, i dont trust the arp's and i dont want to spend another 250 on good headstuds, i dont ever plan to go past 400whp so the stock headbolts will do just fine, the rods will be fine for these levels also. Just waiting on my headgasket.

oh and as far as i know the quikest person ran a 12.1 but there are a couple that say someone ran a 11.9 but ive never seen that timeslip, i saw the 12.1 timeslip, the trap speed was 110mph which i already had at 8psi, 18psi was a big difference over 8psi. so im thinking my trap will be around 113-115mph and with a nice good launch with a 1.7 60 ft or better i think i should have no problem hitting an 11.9 or better with good shifts.

Did that car do it on a BB T25, and stock manifold? If so I don't think you're comparing the same animals.

I also have yet to find someone that has a boosted car that says "Ok, that's enough power I'm satisfied".

haha, its an s13 t25 that is in awsome shape, an s13 tubular manifold, dont know the brand, greddy 3" turbo exhaust outpipe, s4 cams, i went the 13.0 @110 on 8psi, on slicks that mph is good all the way to a 12.1-2 with a really good launch on slicks, with 18psi the power and torque increase is rediculous, i think it was good for at least 3 more mph if not more, and im thinking i can hit my 11.9 or better if all goes well.

And your exactly right, thats why i already want to upgrade turbo and go to around 350whp 320 torque or better, get that extra pull up top mainly, But i want to go for the quickest T25 time.

nice carnage lol , and nice new setup