high psi

[LuNaR EcLiPsE]

ive searched and found nothing, but.... i just finished installing my apex n1 downpipe and catback. when im at wot my boost hits 17psi. is this bad? i have no boost control yet. my mods are intake, bov, and exhaust. 96gst

 

[green machine]

well since the stock turbo doesn't hold high boost very well i say ya its kinda bad. you're getting boos creep from the down pipe. go buy a bc they're very cheap and easy to install.

 

[dave99gst]

spiking to 17psi then dropping off ? or peg'ing 17 and staying there ?

 

[JKGMotosports]

If you did that BC solnoid mod, drop that solnoid back in there. If you didn't, time to get a boost controller of some sort. Your fuel system can take up to 16 psi but more than that you are running a little leaner than you should. The T-25 also runs out of steam beyond 16 psi, you are just pushing in hot air at that point.

 

[DSMShop]

No 17 PSI isnt bad. the kill zone for the 4G63 is 21lbs so even if you were holding at 17 you should be fine.. because even at 21 its not going to kill your engine right away its just going to shorte its life... but something you might want to consider.. that the Stock t25 runs out of its power band at 15Lbs.. so those last 2 arent doing to much good anyways.

 

[LuNaR EcLiPsE]

spiking to 17psi then dropping off ? or peg'ing 17 and staying there ?

it spikes to 17 then drops off to about 14.........

 

[fwdturbobov1996]

No 17 PSI isnt bad. the kill zone for the 4G63 is 21lbs so even if you were holding at 17 you should be fine.. because even at 21 its not going to kill your engine right away its just going to shorte its life... but something you might want to consider.. that the Stock t25 runs out of its power band at 15Lbs.. so those last 2 arent doing to much good anyways.

21 is the killzone? Base on what info and what backing? Locals running 24 psi daily and have been for over a year. Its just all about the tune and how you drive and take care of the car.

 

[JKGMotosports]

Listen even 17 psi can be a kill zone. It all depends on your air to fuel mixture, you run too lean even at 12 psi you will blow. The 4G63T motor can handle a lot of boost with the proper tuning of course. Why don't you strap on a 60 trim and run it at 15 psi with your stock fuel system, take a few 1/4 mile runs and let me know what happens.

ANYWAY, if you are spiking to 17psi at a lower rpm and dropping to 14 psi after you are fine. So you are 100% fine and don't worry! Just get a MBC or an electronic Boost controller your choice. I would still get a fuel pump just to be save or rewire your stocker.

 

[Talesin]

Yeah, that sounds like the larger exhaust causing a spike. You might want to check your actuator, or the vac lines going to it. An MBC will NOT fix boost spike or creep, as it'd have to add extra pressure to the actuator line; boost controllers *raise* boost by bleeding off a bit of the air pressure that would normally go to the wastegate actuator.

And personal opinion, the electronic ones aren't worth it... overpriced shiny-blinky, when all you actually need is a $15 (or cheaper) bleeder valve, set up right.

If it was going up and STAYING up, that'd be creep. You can reduce that by having the wastegate ported and putting on a larger flapper.



Also note that if you overboost a turbo, it has to work a lot harder than it was designed to, and so will break down sooner, as well as not providing the amount of actual boost that a turbo working in its spec range will. But then, larger turbos aren't an early upgrade, on a DSM.

 

[fwdturbobov1996]

Listen even 17 psi can be a kill zone. It all depends on your air to fuel mixture, you run too lean even at 12 psi you will blow. The 4G63T motor can handle a lot of boost with the proper tuning of course. Why don't you strap on a 60 trim and run it at 15 psi with your stock fuel system, take a few 1/4 mile runs and let me know what happens.
.

Thats exactly what i just said .. " all based on the tune ... " . stock fuel system no.... mine cound handle 15 lbs. Anyways.