Thread: 21 psi from a T25 = no good. hahaha

^^^ I had a T25 2 years ago and I made 250WHP/260TQ at 12psi. I have a GT28R now. Some people got tight budgets and can't really afford to be changing turbos like underwear. Is your turbo and you can run 30psi if you want. The point of my post is to make an statement that is not healthy for the turbo to run that much boost.

if you think the T25 takes a beatting you should try a T28 from thr GTI-R it will take it all day long.

exactly just because its somewhat out of its range doesnt mean it cant make power. jusr doesnt last as long.

your air fuel tuning is key tho, becuase you can make greater power at lower psi levels with better air fuel ratios and if you are making greater numbers at lower psi, then when you get into a efficent range of power you can only imagine how much power it is going to make.

good point, you gain a ton of torque down low. when it was boosting 20psi you could feel the torque down low even with a 10.0:1 a/f.

bad news guys, cylinder 4 which melted the plug detenated again and the rings are blown out, im sure the ringlands are what gave. It sounds like a wrx. haha and the plug has oil all over it. I dont see a reason why it would have detenated though, my a/f was tuned to a solid 11.5:1 which is still rich. but its just that #4 cylinder which has had problems. i dont get it. i know the 21psi boost is probably what did the plug in but seriously i did one pass from 30mph in second through 4th gear and it was solid 11.5:1 a/f the boost was set and spiked to 15psi, held 14psi till 6krpms then slowly bled off to 12psi by redline the car pulled sooooo freakin strong. tires stayed spinning till almost 80mph and even wanted to break loose in 4th gear. It was sooo much faster than 8psi. and just think i ran a 13.0@110mph on 8psi on street tires. Second attempt through the gears to make sure it was good to go i was into 4th and then bam, lost power and blue smoke everywhere and filled my cab, i thought my car was on fire. i pulled over slowly and checked. the dipstick was blown out which i knew was the rings gone being 14psi of boost now went into the crankcase. oil blew all over my piping and hood and out my breather on the valvecover.

Im at a loss on what to do. Should i get a new jdm or just buy some cp pistons after tearing apart the head to make sure the walls are not scoured. Im not looking to make a ton of power. i know the stock sr20 rods are good for 450whp, im just looking for the 300whp range or close. 280-300whp and same in torque being these t25's make some hella torque. I guess i will have to tear apart the motor and see the damage. hopefully the walls are good. If so im thinking i will just go with a lower compression cp piston.

Let me know what you guys think.

i would rebuild it, with aftermarket parts if possible, so you can crank that boost up safely

Thats what im thinking too but its still weird that it was only on cylinder 4 that was having problems. i dont know if its the sti injector not working properly or what, it shouldnt have detenated at an 11.5:1 a/f at 14psi of boost, timing is at 15*. I dont get it. I guess im gonna tear the motor apart to check it out. if the walls are good, im gonna go with a new set of pistons to handle the upped boost. i knew i should have put some 100 octane in there before i started. being im only gonna run 8psi daily and 14psi on occasion. we have crappy 91 octane here. The only thing is i pulled the plugs from 1-3 and they were awsome. clean with no sign of detenation at all. a little sooty like you want them to be but no soot on the insulator itself. No sign of running lean such as whitening of the tips. Just the number 4 had oil on it. Im kinda confused?

All it takes is one run at 21 psi on pump gas and you have a probelm. A T25 turbo at 21 PSI is been over spun and is generating very high air temps.

It does not matter if your fuel mixture is ok.

You can damage a piston from a few things which will cause detonation.

1. running lean
2. running to low of an octane
3. to high cylinder temps (which causes a diesel effect)

yeah im thinking it was the octane. thats the only thing i can think of at 14psi that would cause it to detonate. expensive lesson learned. Well i think ive come to a decision to sell the parts on it for now being im short on cash to build the motor. Thats not a priority as of yet, so i will be back with a built motor and bigger turbo later on but for now its gonna wait....
im gonna post the parts for sale in the turbo section. i have lots of them. Hit it up.....

I doubt it was your turbo over boosting that did it though. It was most likely that something else was going on with the cylinder and with the 10:1 compression,and the boost spike the cylinder probably had enough.

I was loosing traction in fourth the other day and probably couldve in fifth if it didnt poppout with power. I was like WOW this **** is running STRONG(you know that feeling when your turbo car is running too strong and you know somethings wrong?). Looked over at the boost gauge and it was pegging 20psi! Nothing was hurt though. I knocked the boost down to 18 and STILL lose traction in fourth!

BTW man sorry about your motor. I was looking forward to us battling it out for fast T25 times!

well its not a 10:1 motor its a 9.5:1 but still, something was up, it was just that one cylinder. oh well, i will build a bigger better motor later when money permits, i got a little too anxious. yeah this thing pulled freaking hard but oh well you gotta pay to play. I was looking forward to getting the fastest t25 time also i think a high 11 on slicks would have been possible at this boost level if it was running right. it wanted to spin 4th but tires are pretty grippy for what they are. it hauled. definetly a big difference over 8psi. i knew i should have run the 100 octane race gas. it probably would have saved the motor.