I just got my 98 eclipse gst spyder about 3 months ago... When im driving it.. The blow off valve seems like it is letting a lot of air out while the turbo is in use. Im wondering if there is some control you can do to let less out to gain more power, or is this a thing that Needs to be happening. Ive drove a few and didnt notice anything like this.. Do I have an aftermarket bov? or could it be damaged?

 

stock bovs leak at 12psi. get a boost gauge, then an aftermarket bov and a boost controler if you want more boost.

 

What can a stock turbo push for psi?

 

its worthless to boost more than 17psi on a stock turbo, you just start blowing hot air and dont make any more power. make sure u have a bigger fuel pump if you go that high though

 

what kind of horsepower difference are you making pushing around 15 psi?

 

i've heard a few posts about when you increase boost you will start to just push hot air, how's this? thanks

 

to understand this you need to understand how a turbo works. its got 2 wheels attached to eachother, one on the exhaust side and one on the intake side. The exhaust side spins and cause the intake side to spin as well. once it starts sucking in more air on the intake side the exhaust side can then spin faster and in turn suck in even more air. This is how a turbo build up boost and why you ahve turbo lag. Anyway, the smaller the turbo is (the stock turbo is VERY small), the faster the wheel has to spin in order to boost. However, it needs more exhaust to get it to spin so fast. This cause the whole turbo to get much hotter and causes the intake air to heat up. the hotter the intake air is, the less dense it is, the less oxygen it has, and you cant make as much power. also, hot air increases engine knock and that retards timing then you lose even more power.

All turbos have an efficiency range and generally the larger the turbo, the more efficient they are. small turbos are good for quick spool up but arent good for lots of boost. stock turbo is good for about 16psi before it starts to get too hot.

 

they say that a stock GST has 210 hp. Is that 210 running 12psi or is that 210 if your pushing your turbo @ 15/16 psi?

 

210hp is irrelevant thats just a factory rating. Stock the car dynos between 160-170 hp to the wheels. It is possible to get roughly 40hp more out of the stock turbo by both freeing up all restrictions in the intake/exhaust and turning the boost up to ~17psi

 

okay. so the hot air is just being generated by the turbo heating it up? Got it, Thanks