too much boost!

[67racing]

Maybe someone can help me.

I just built my 2g eclipse turbo, with forged internals and a 20g. the intercooler and charge pipings are all stock. with the stock blow-off valve, the turbo wont boost past 10 psi, because its leaking. but when i put on a used apex twin chamber that i had, the boost would go up to almost 20 psi.
the turbo came with an adjustable wastegate actuator, i set it so it just has a little pretension on their (like 2 mm preload) if i make it looser than that, the boost goes down, but the turbo doesnt start boosting until 4500 rpm.
i have just been using the stock blow off valve, but maybe there is a solution to my problem.

thanks for any advice!

 

[67racing]

i also hooked up a boost controller, but it doesn't change anything.

 

[Sean485]

Step 1: Cease driving car with stock fuel and intercooling systems with a 20g turbocharger
Step 2: Get a real intercooler, upgraded fuel pump, afpr, big injectors, and a decent bov
Step 3: Tune car and resume driving

A 20g at 10psi is far more airflow than your stock fuel and intercooling systems can handle, if you keep trying to drive it you will blow it up.

My $.02

 

[Rick4g63]

Sean is absolutely correct

The stock I/C piping have to go.
The stock bov is good for a paperweight.

RC 660 injectors, greddy new type R BOV, Walbro 255 lph, FP Fuel Rail and APR with gauge, Victory Performance fmic and piping, greddy e-manage with wide band o2 sensor,boost , egt and air fuel gauge.

What internal do you have?

 

[67racing]

For the fuel system, i have 550 RC's, and a vr4 turbo pump controlled by SAFC. so far i had to lean everything out a lot, because it would always run to rich. for the internals i have the B-shafts removed, and my rotating assembly balanced. ross pistons and eagle rods. the car runs perfect with the stock blow off valve, just no more than 10 psi of boost. the air/fuel ratio is good, a little to the rich side.

why would it screw anything up if i keep driving like that? i would assume that nothing should happen, becasue everything is just running at about 1/3 of its potential.
thanks for replying!

 

[Sean485]

For the fuel system, i have 550 RC's, and a vr4 turbo pump controlled by SAFC. so far i had to lean everything out a lot, because it would always run to rich. !

Do you have an AFPR? You need to lean it out because the ecu doesnt know the injectors are larger... thats how it works, bigger injectors = remove airflow with safc to fool ecu... thats basic stuff, if you dont know that you best learn it real fast...

550's are too small, 660's minimum

As for why would it mess anything up if its only running at 1/3 potential, it will mess it up because 1/3 of the potential of that turbo is 5 times what the stock IC systems were designed to handle.

Not trying to be an a$$, but I suggest you take a few days and start researching these things and doing mods in the proper order or you will be running consistant 15's at the track and/or blowing the motor.

Edit: Also, that blinkey blink A/F gauge is pointless, get a wideband if you want to know how rich/lean it is.

 

[67racing]

since i wasn't plannig on boosting more than about 15 psi, the shop that sold me the 550
s and the pump said, they will be fine for that application.

 

[Quasimondo]

I doubt 550's will be enough for a 20g, even at 15psi. I have 650's with a small 16 boosting at 20 psi and they're pushing their limit. When you say VR-4 do you mean Galant VR-4 or 3000GT VR-4? If you mean the 3000GT fuel pump, you may want to upgrade. According to this chart, that pump is rated at 150 lph (170 if it's re-wired). I don't think that's enough for a 20G They have a supra fuel pump for comparison, which I think would be an excellent pump for that turbo.

My advice on supporting mods is to always overdo it. When they tell you it can be done with a 2.5" exhaust, get a 3". If they tell you it'll be fine with 550's go with 660's. If they say a 190 is good enough, get a 255. It's better to have that safety cushion than to try to tune on the hairy edge and get caught out there when what you have to support that turbo isn't enough.

 

[67racing]

Once i will save up some more money, i will upgrade all these things. the car is my daily driver right now, so the question is if it would be save driving it on the street with the stock BOV maxing out at 10psi, or could i really mess something up like that?

 

[Quasimondo]

You should be fine at 10 psi, but I wouldn't raise it until you have the supporting mods in place, especially the fuel system upgrades.

 

[Rick4g63]

Quasimondo I agree with you 100%. You are very knowledgeable and a "safety cushion" is always welcomed when modifying an engine.

With all those internal, a 20g and using a 2g bov boosting at 10 psi is like buying a ferrari enzo and using it as a grocery getter....

Quasi, view my mods, I dynoed at 280 hp and 290 ft lbs of torque at 22 psi from a pos T-25.
I did some more extensive porting and ready for the next dyno session to break the 300 whp mark. Can I do it with a T-25?

 

[67racing]

You should be fine at 10 psi, but I wouldn't raise it until you have the supporting mods in place, especially the fuel system upgrades.

I can't raise the boost anyway, since my BOV doesn't let me. I was just wondering, since Sean (above) said i will blow my engine like that, just wanted to get a second opinion.

 

[oldman]

I can't raise the boost anyway, since my BOV doesn't let me. I was just wondering, since Sean (above) said i will blow my engine like that, just wanted to get a second opinion.

Sean is right, you don't have enough supporting mods for a 20g. I would like to add one thing to what everyone has suggested, Do a boost leak test, sounds like might have some.

 

[67racing]

Sean is right, you don't have enough supporting mods for a 20g. I would like to add one thing to what everyone has suggested, Do a boost leak test, sounds like might have some.

i already know that i have a boost leak, and i know that i am missing supporting mods to increase the boost, but for right now, i just wanted to make sure to be safe street driving the car with 10 psi and the mods that i have.

 

[Sean485]

No, it is not safe at 10psi with a 20g and stock intercooling. What kind of wastegate are you running? Internal or external? If its internal disconnect the flapper arm from the wg flapper and drive it with no boost if you have to drive it, otherwise if its external, find another car to drive until you save more money, sell the 20g, put a t-25 back on and use the leftover money to buy some supporting mods, or just blow up your nice new engine. Makes no difference to me which you choose, its your money.

I would show you a compressor map of the 20g compared to a t-25 to elaborate why you cant do it but since you seem to REALLY need to do a bit of research on your own about correct order of mods, common termanoligy, and how to operate an safc, i'll let you figure it out...

PS. http://www.dsmtuners.com/tuning-guide/