Max boost with stock 370cc injectors?

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

I know this seems like a very obvious and stupid question, but I have been getting different opinions on this and want to get to the bottom of it. I did a few searches and did not come up on much.

It seems to be the general consensus on this board that the 370s are good to 14psi. However, Wayne from Phase2Motortrend said that I should not boost past 10psi with the stock injectors, particularly because I have the t28. Now I am a bit confused and want to make sure I don't run too much boost. Isn't 14psi the same regardless on what kind of turbo I have? I am installing my s14 SR next week and have all the basic mods (FMIC, dp, exhaust., etc.) to make sure the car runs nice and cool and smooth. I am retaining the stock t28 and 370cc injectors. How much boost can I really *safely* run? I don't know if this affects this alot, but I am also located at about 8,000 ft. elevation.

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

Hokiruu - A T28 will flow more air at 14psi because it has a greater efficiency and the air is "cooler" and therefore denser than the same 14psi from a T25

Stay at 10psi with a T28 and stock 370's

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

Ahhh. Duh! Thanks Keyy

Post by **Drakon** » Mon Jun 09, 2003 5:27 am

Hey also that 10 psi is the number while using the stock side mount right? with the front mount you can boost a little higher i think.

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

...so once i have 550's, how high can i boost on the t28?

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

Sky is the limit there with the T28 (within efficiency of course

)

Website · Post by **the_invisible** » Mon Jun 09, 2003 5:27 am

uhhhh, I think that even with an adequate fuel pump and injectors, you still need fuel managements and computers to safely boost it. Simply swapping in injectors and raising the boost is not safe.

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

good call, I retract that statement, you will need an FPR, some type of piggyback fuel computer and possible an ECU retune...

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

well I know THAT... I just meant once I had 550's working and installed, which means fuel management of some kind. but when is the t28 at the top of its efficiency range?

Post by **SWIFT_DRIFT** » Mon Jun 09, 2003 5:27 am

well im boosting .9 bar (13 psi) on stock smic, t25, stock injectors. I have absolutely zero problems. just pretty much maxed out the stock setup since im upgrading everything here pretty soon.

Post by **B.L** » Mon Jun 09, 2003 5:27 am

Raise your fuel pressure and you can run 1.2 bar (17psi) on your 370cc injectors.

1 bar or 15psi is not a problem at all.And yes i know a lot of people doing this and fueling is fine!!

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

17psi? Do you mean increase fuel pressure by adjusting the fuel pressure regulator by the fuel rail? Will I need an aftermarket FPR? I still need to know the approximate efficiency range of the s14 t28. Anyone have any info?

Post by **SWIFT_DRIFT** » Mon Jun 09, 2003 5:27 am

efficency wise the s14 t28 is the same as the s13 t25, meaning around 13-14 psi. you might push it to 1 bar (or 14.7 psi)

Post by **Drakon** » Mon Jun 09, 2003 5:27 am

Dang Swift your really pushing your limits, you have no room for insurance. wuw. Seems your running it ok but i wouldnt recomend to many people to push it that high on stock setup.

Post by **turboex** » Mon Jun 09, 2003 5:27 am

Im in the same boat, but i have an hks gt2530. Where should i keep it at? thanks

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

240_Keyy wrote:Hokiruu - A T28 will flow more air at 14psi because it has a greater efficiency and the air is "cooler" and therefore denser than the same 14psi from a T25

Stay at 10psi with a T28 and stock 370's

SWIFT_DRIFT wrote:efficency wise the s14 t28 is the same as the s13 t25, meaning around 13-14 psi. you might push it to 1 bar (or 14.7 psi)

So the t28 is that much more efficient than the t25 that I have to run it 4psi lower than a t25 in order to be safe? Seems like a bit of an overcomprimise, but until I am told otherwise I will keep it at 10psi.

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

you will *probably* make about as much power at 10psi with the T28 that you would make at 14psi with the T25 hence the injector limitation...

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

Yay. Thanks again Keyy, you are a most helpful and knowledgeable individual. That is the kind of info I needed.

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

np man

Post by **nismodave** » Mon Jun 09, 2003 5:27 am

I have a t28bb and had 370s , I boosted 14psi with no problem.

Post by **hokiruu** » Mon Jun 09, 2003 5:27 am

nismodave wrote:I have a t28bb and had 370s , I boosted 14psi with no problem.

:smoker eehckselent!

Website · Post by **badass240sx** » Mon Jun 09, 2003 5:27 am

nismodave wrote:I have a t28bb and had 370s , I boosted 14psi with no problem.

Sorry to bring back an old thread; just curious, 14psi on the stock fuel pressure? Also, what was your timing set to?

Post by **TruboostPerformance** » Mon Jun 09, 2003 5:27 am

I am running 17psi with upgraded fuel pump

Website · Post by **badass240sx** » Mon Jun 09, 2003 5:27 am

Ughhhh, your running 17psi with stock fuel pressure on the S14 T28 BB? No FMU/FPR or anything? How about your injectors, stock 370's? Most importantly, what did you set your timing at? I ask because currently my S14 SR20 when boosting 10psi I *think* I hear very slight ping on the topend.

Post by **ImportIntelligence** » Mon Jun 09, 2003 5:27 am

21psi - stock injectors, SAFC and walboro. Just barely starts to lean out at 6000+ RPMs

Website · Post by **badass240sx** » Mon Jun 09, 2003 5:27 am

::Jaws drop::: SAY WHAT? lol...that is insane! T25 or T28? NO FMU/FPR?? stock fuel pressure?? If so, what the hell was the timing set at? I really need to get a timing gun and check mine, theres no way im pinging around 5-6k rpms @ 10psi if that's true unless my timing is wayyy advanced.

Post by **turboex** » Mon Jun 09, 2003 5:27 am

ImportIntelligence wrote:21psi - stock injectors, SAFC and walboro. Just barely starts to lean out at 6000+ RPMs

What kinda power are you putting down at that psi?, and is this stock injectors?

We threw my car on the dyno just to see when the fuel would stop. this was with a hks gt2530, tublar mani, 3inch exhaust, stock intercooler, and walbro pump. the car ran 15psi and still stayed far above the danger level fuel wise. But I stoped there due to risking my stock head gasket.

Post by **240_Keyy** » Mon Jun 09, 2003 5:27 am

stock headgasket should be good for over 300hp...

My friend on completely stock internals is putting down 326 with the CTC kit and has been for quite some time now...

Website · Post by **badass240sx** » Mon Jun 09, 2003 5:27 am

So does anyone know what their timing was set at while boosting this high?

turboex: 15psi on the stock SMIC? sounds like that is definitely pushing it's limits, eh? What kind of numbers did you produce? Stock injectors?

Post by **turboex** » Mon Jun 09, 2003 5:27 am

It was i the high 200's but the hp droped very fast as the intercooler heated up. So we just quite. My hks-s intercooler gets here thursday. Then im good to go. I honestly dont know when the stock fuel is not enough, but im guessing at about16-18psi on 92 octane. But thats just a guess ill get better numbers later. Now dont anyone go trying this and blame anyone on this post if your **** blows up. My motor also has about 38,000miles

Max boost with stock 370cc injectors?

Max boost with stock 370cc injectors?

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