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GSTdude06

15+ Year Contributor
481
11
Oct 29, 2005
Mesquite, Texas
I have a 1997 Eclipse GS-T and I just bought a 14B turbo, ported manifold, ported o2 housing and a better side mount intercooler for 300$ sounded like a great deal to me but I might be wrong. But I was wondering how much boost I can run with everything else stock except my intake and I have a BOV. And how much hp would I get pre psi? ( Ill get a boost controller to change the psi higher) but how much could I run with everything stock and with a boost controller?
 
I just want to know how much boost I can run stock and how much hp each psi gives me.
 
I think the stock fuel system can only handle up to 15-16 psi.... If I were you I'd Look into a new fuel pump to start with, then some injectors and a S-AFC II...

And you do have an aftermarket boost gauge right?
 
You can't calculate hp/psi of boost. There are too many variables to figure and each car will be different. Threads have been locked over this question, so don't even try. On a 14b, with no fuel mods and an aftermarket BOV, you could probably safely run anywhere from 10-14 psi without serious issues, but a fuel pump and/or fuel pump rewire is highly recommended.
 
Until you at least install a Walbro 190 fuel pump, I don't recommend any more than 15 psi. On top of that, if you do want to run more than 15 psi, you should purchase an AFC and a logger so you can monitor your engine so you don't blow it up from running too much boost and not enough fuel.
 
Yea i'd highly recommend a logger of some sort. I have a pocketLOGGER and i really can't complain...
 
Currently your car will be limited by its ability to provide fuel to the cylinders. As the ammount of fuel required is a function of mass flow and not absolute intake pressure we are unable to provide you with a definative answer to your question. I suggest you do not listen to any of the information given here reguarding the allowable pressure and instead acquire the necessare monitoring devices (a logger) to tell when you are exceeding the capability of your current fuel system.

Clear enough for all?
 
Although a new thought occurs to me... If you don't have a manual boost controller and are still operating on the stock boost controller, you won't have to worry about how much boost you can run. The ECU will figure it out for you. On mine it worked out to 8 psi.
 
in newb terms, go til you hit fuel cut and take it down 1-2 psi from that, assuming you dont have any knock at that psi... for me it was 18psi when i hit fuel cut, so i took it down to 16, still had knock, so i settled at 15.....
 
the 14b's peak efficiency is probably what, 19lbs? correct me if i'm wrong, i'm just estimating
 
tstkl said:
in newb terms, go til you hit fuel cut and take it down 1-2 psi from that, assuming you dont have any knock at that psi... for me it was 18psi when i hit fuel cut, so i took it down to 16, still had knock, so i settled at 15.....
Wrong, hitting fuel cut has nothing to do with your ability to deliver fuel, it's triggered solely by air count. The reason you are hitting fuel cut at 18psi is probably due to some other issues, leaks between your maft and the intake valves being the number one culprit. When I was still on stock fuel system, my 16G was creeping up to 25psi before I hit fuel cut, does that mean I can run 24psi? Don't think so.
 
The only two accurate replies in here are from crankbender and oldman. Don't increase the boost until you get a logger. Anybody that says otherwise doesn't have the neccesary experience to give you advice.
 
And an aftermarket boost gauge. As always, the stock gauge is crap. I'd personally get the new gauge first. The thing about the 14b as opposed to the t25 is that it won't peter out as much at the top end, and it won't lead to IC heatsoak in as short order. The ability to run a higher target boost is just a side-effect of the bigger compressor efficiency map footprint.
 
I have a stock fuel system with the one and only T25...intake some intercoolerpipes...greddy type s bov... greddy 3inch cat back... act2600 clutch with superlight weight flywheel... i also do not have a boost controller could never decide between getting a manual and opening my wallet for an electronic... im hitting anywhere from 19-21 psi in just about every gear the only time i hit fuel cut is when i stay at wot... if i hit 19-21 psi n let off so it drops to 16 n hold it there im fine... what do you guys think I should do about that? i was thinking i should rewire fuel pump and see if i still hit fuel cut hoping i have some sort of factory beast... should i go ahead and just do new pump, injectors, fuel pressure reg. and afc?
 
EclipseGST-95 said:
I have a stock fuel system with the one and only T25...intake some intercoolerpipes...greddy type s bov... greddy 3inch cat back... act2600 clutch with superlight weight flywheel... i also do not have a boost controller could never decide between getting a manual and opening my wallet for an electronic... im hitting anywhere from 19-21 psi in just about every gear the only time i hit fuel cut is when i stay at wot... if i hit 19-21 psi n let off so it drops to 16 n hold it there im fine... what do you guys think I should do about that? i was thinking i should rewire fuel pump and see if i still hit fuel cut hoping i have some sort of factory beast... should i go ahead and just do new pump, injectors, fuel pressure reg. and afc?
You need to bring the boost down to 15-16psi either by installing a mbc or properly hook up your factory bcs, it's so wrong to run a T25 @ 19-21 on stock fuel system and smic I don't even know where to start. Are you running the car with the actuator vacuum fitting open?
 
oldman said:
You need to bring the boost down to 15-16psi either by installing a mbc or properly hook up your factory bcs, it's so wrong to run a T25 @ 19-21 on stock fuel system and smic I don't even know where to start. Are you running the car with the actuator vacuum fitting open?

I never messed with any vaccum lines on my car... the biggest changes i noticed in my boost jumping up were taking out the turbo silencer which used to be on the lowerintercooler pipe... i ended up just replacing with a lower intercooler pipe...i also saw changes cleaning out my side mount with gasoline.... and i gapped my sparkplugs at the lowest factors specification .028 i believe... call me crazy if you want but before i gapped my plugs i could only hit 16 psi and it would drop to like 13-15 maybe something broke but summer time when i did that it started hitting 17-18 and now in the winter when the car is fully warmed its hitting 21...i hit 22 the other day for a split second n it dropped to 21...

but as for my question...im thinking about doing the fuel pump rewire n see if i notice any differences (like not hitting fuel cut for one) and if that doesnt work ill do a whole fuel set up... with uncontrolled boost like that could i safely run that range in psi if i had the fuel mods for say and evo III 16g? honestly you guys will think thats dumb that i might as well upgrade the turbo but my turbo is good enough for me i kno i would be happy with my cars performance if it didnt hit fuel cut most people say the t25 is useless n blows hot air after 16 psi but i dont see that at all i see a noticeable difference in all temperatures throughout the year from 16 psi to anything above that point including 21 psi...what should i do FUEL wise not boost wise... and can i run this much boost if i get better fuel mods?

by the way this car has been babied for 57,000 miles before i got it it now has 77,000 miles on it and an old lady had it before me so it was bone stock nothing ever tampered with or changed...i dont know too much about the vacuum lines i kno theres a free mod to remove something along those lines but i havent messed with it so i dont kno the answer to ## question
 
If you have never messed with the vaccum lines going to the wastegate then somthing is wrong. The factory wastegate is like 10-11psi, the only way to get it higher is a mbc or a bleed before the wastegate. Mabey you knocked a hose off, just taking out the silencer will not affect boost like that. You can say what you want but any thing over 16-17psi on a t25 is a waste and will lead to eary failure. I dont think everybody on this site is wrong and you have a super t-25. Just my humble opinion.
 
I checked today and I traced every hose around the waste gate area... nothing is hanging... i thought it was very strange that with every modification that i put on my car i saw an increase in psi while my friends dsm isnt seeing any gains in psi and he even has one more modification than me (a downpipe) and hes only hitting 13 psi i believe... im honestly not bsing anyone i have one person on tuners that can vouch for me hitting that much pressure... i did see an increase from taking the silencer off it was approximately 1-2 psi... if i have to video tape it i will but... the question i am asking is how do i continue to safely run that much psi without the occasional fuel cut miss... someone told me that i wouldnt have to do fuel mods with a t25 but if im hitting fuel cut... i would think i would have to... would i be able to get away with a fuel pump rewire or would i really have to do the fuel modifications that one would do for an evo III 16g for my t25? these are the questions i need answered...

An other possible reason for this much psi that i have heard stories of...cats that are fried become clogged up which just creates bad flow in the exhaust resulting in an increase in turbo pressure... is this true... would getting a downpipe decrease the turbo pressure due to the increase in free flowing exhaust?
 
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