how much boost can the stock turbo handle???
 

this may be a repost (im pretty sure it is lol) but i couldnt find it when i searched!

basically as the title suggests...; how much psi can the stock turbo handle??
with a few other mods like
- front mount
- dump pipe - 3 inch exhaust - hi flow cat
- 850/1300cc injectors and fuel rails
- fuel pump
- apexi power fc + pfc boost controller

just minor mods as such....

and what would be the estimated power gain???

p.s what is the stock turbos on a FD?? a series 8

10 lbs i think, research it.... i found out there are many threads that ask the same question.

what kind of turbos are in a fd?

I think you can run up to 14psi without any problems.

I am running 13-14psi on the stockers with no problems

then disregard my previous post... lol

i run 14-15 all the time, no problems

If your tuned for it you should be able to do 14 or so. Its just gonna wear the turbos a little more than stock, but they should be fine. When your freeing up your intake/exhaust be careful of boost creep/spikes. Always watch your boost gauge after modding the car.

10psi refers to the stock turbos on the stock fuel and ecu. You can go higher, up to numbers like 14-15psi, IF you have appropriate boost control, fuel upgrades, and ECU tuning.

More boost without the proper support means detonation and a destroyed engine. You can't wander aimlessly into these mods.

Dave

the stock turbochargers can produce 17-18 psi, however their flow efficiency starts to dwindle at around 14-15 psi, and unless you are running nitrous or I guess a air to water intercooler loaded with ice, you are not going to make any more power past 14-15psi, plus you will wear out the turbos fast and you could even make less power considering the air intake temps will be extremely high

I don't remember the exact *technical* term used. But anything past 15psi on the stock (pre- 1999) turbos is just wasted air. 15psi is the max efficiency due mainly to this being the point where the blades begin to spin at such a high speed they super-heat the air they are meant to be compressing, making the air molecules expand, counteracting the idea behind using turbo's (compression).

I am still running the stock twins, pushing 12-13psi with the PFC. Personally I dont want to go any higher than that for reliability sake... If you do want to boost higher and still keep the twins than you may wish to look into a pair of BNR's.. If I didn't move to England when I did I would have gotten a pair for myself. I believe Goodfellas had some in his for a while with great results.

You're talking about the compressor efficiency game.

Higher pressure intake air makes more power. Higher temperature intake air makes less power.

If you simply turn up the boost on a set of turbos, they will produce more pressure but also they will make the intake air hotter. Efficiency is just a number that represents how much energy goes into boosting pressure, and the rest of the energy goes into heating the air.

So when you get above 15psi on a stock turbo, you're making so much heat that without an extra-special intercooling setup you'll make less power overall. It's around 15psi when most sensible people decide that it's better to use a turbo that is designed for better efficiency in this power range. (The tradeoff is that this bigger turbo takes longer to spool).

For anyone who'd like to know more about this stuff, consider reading the intro material in the single turbo forum or buy a book like the one by Corky Bell.

Dave

Note: 7,10, 15 psi on the stockers is not the same as 7, 10, or 15psi on a single or bnrs. There's a brand new thread in the archives where this was all debated. The stock engine, turbo, and fuel system are good for 10-14psi *depending* on your injector duty cycles and afr's. I would not crank the boost past 12psi w/o being able to monitor duty cycles & afrs.

They're Hitachi HT12s, I think that holds for series 8 also...

all of the domestic FD's were HT12's. The '99 twins were different but they were never sold here.