Finally hooked up a Fuel pressure gauge to my car under boost.
@ 5.5psi I'm running about 85-90psi of fuel pressure
@ 7.5psi I'm running about 95-98psi of fuel pressure.

So, I would say not getting enough fuel isn't a problem with the Star kits
I've got some kind of ignition retarding going on. Its either a over active knock sensor, crank angle sensor or something ignition related. I hop eits not a faulty injector, biut I would have noticed discoloration on my plugs on inspection.
Its very intermittent though. Sometimes it feels faster than hell, other times it can't get out of its own way!

Anyway, that should clear up any fuel pressure/fuel delivery problems you guys had questions about.
Wyatt Leras
http://www.turbogs.dsmpower.com
98 Eclipse GS Star Stage 5,000 Turbo kit

Hey guys tell me what you think of this setup...

A vortech 10:1 FMU with 310cc injectors @ 8-10psi ???



thanks,
Martin

You know Martin I had actually thought of that. Though, I was going to use a bleeder kit on my 12:1 unit and go with 310cc injectors. Seeing how the stock ECU can still read them. Sounds like it would be perfect, you could probably even run higher boost than that.

91 awd: 60-1, 880's, E-Prom, etc.
93 awd: JDM 6 bolt, K&N, full exhaust, Wally 255, otherwise stock.

R.I.P. the original "Factory Freak"
15.5's with short ram and catback only
1996 RS 5-speed

That's great Wyatt. Exactly what I wanted to see and hear. Where did you put the fuel guage in-line in relation to your fuel diagram shown in the other post, if I might ask. I'm also a bit confused on two other things then.

How does the stock FPR interact with the 12:1 Vortech one to come up with whatever fuel pressure it does?

Does the T04/03(b) and (e), being a bigger turbo than the s-16g, require a certain amount of additional fuel that we don't know about?

This is great information either way! What are your EGT #'s like as well when your really pushing it?

Keep that info coming!

Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)


http://springfielddsm.homestead.com/JasonsPics.html

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)

a T04/03 won't require any more fuel than a S-16G if they're running at the same PSI. at any given rpm, if the boost is the same they are pushing the SAME amount of air. boost thresh-hold, lag and high-rpm boost capability are the only things that change with turbo size. the AMOUNT of air that they push is determined by the PSI and your engine's displacement. so a fuel pressure/injector size that works with one turbo will work with another for the same boost level.

LAST EDITED ON 22-Dec-00 AT 09:44 AM (PST)

I can't se this as true, Hoot.

I think we've already spoken to his one time, but I just wanted to get your grasp on it.

>a T04/03 won't require any more
>fuel than a S-16G if
>they're running at the same
>PSI. at any given
>rpm, if the boost is
>the same they are pushing
>the SAME amount of air.


So, are you saying a Super 20g and a T-25 both pushing 10 psi are giving the same amount of hp? That's in effect what I think you're saying if they need the same amount of fuel per level of boosted psi. Fuel = hp. Simple truth is that each turbo has different flow rates called CFM's. The T-25 has a ridiculously low flow rate, whereas a race turbo such as the Super 20g has a laggy high, high flow rate. Each would hit 10 psi at different rpm's, but the difference in hp and needs for fuel would be enormous.


> boost thresh-hold, lag and
>high-rpm boost capability are the
>only things that change with
>turbo size.

All of these things are contributing facts to what makes a turbo different and unique to someone's turbo application, but I would add that fuel ALSO needs to differ uniquely to every single turbo application as well.

the AMOUNT
>of air that they push
>is determined by the PSI
>and your engine's displacement.

That's true and also the turbo and compressor capacity(the amount of air the turbo can hold and push through it's compressor) Since a T-25 needs only a little bit of air to fill up it's compressor and turbine blades, it spools quickly and needs smaller amounts of corresponding fuel at a certain level of psi to create your car's most efficeint stoichiometric(sp?) ratio.


>so a fuel pressure/injector size
>that works with one turbo
>will work with another for
>the same boost level.

I respectfully disagree b/c of my previous comments. I look forward to your take on this Hoot.

Therefore, it's my opinion that the T04/03 turbo would need a "different" amount of fuel than does the S-16g. Albeit maybe a small amount, if each turbo has different flow rates, in which I'm sure they do, they will also need different fuel pressures.



Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)


http://springfielddsm.homestead.com/JasonsPics.html

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)

if a t-25 and a super 20g were pushing the SAME PSI at the SAME RPM, then the hp would be the same. (except when you calculate in the fact that the smaller less efficient compressor wheel is heating the air more than the larger wheel). it's a matter of simple logic. consider the internal volume of the cylinder. if you pressurize it to 10 psi, what difference does it make what you used to pressurize it? it's the same volume of air and will require the same volume of fuel to be stoich.

a CFM rating will not come into play unless you try to push more air than can flow through that housing. like if you tried to boost to 16 psi then the Tiny-25 will certainly not be able to maintain that pressure level at a high-rpm flow rate. the 20g will and THAT is where the difference in fuel systems will be needed. because the 20g will STILL be at 16 psi at 7000 rpms but the t-25 will have fallen off to maybe 12 psi. but if we're talking about the same boost at the same rpm... what's good for the goose is good for the gander.

unless you make a very poor choice in turbo size any of the turbo's should require the same fuel for the same boost. if your turbo can't keep boost at high-rpms, it's too small for your engine. small differences created by one turbo spooling quicker than another will be minimal and handled fine by the ecu (unless you have larger injectors and then of course you need an afc).

the different turbos that have different flow rates and efficiencies will make the engine respond different. the idea is to choose a turbo that matches the size of the engine and the boost level desired. there is no ONE turbo that will work for this. any of the sizes that come close are fine.

so 2 liters of air at 10 psi is the same no matter how you cut it. but like i said, only if that boost is the same at high-rpm. if you're only running 5 psi, then a t-25 will have no problem maintaining that pressure up to redline. the 20g @ 5 psi will require no more fuel since it's only giving the same amount of air. it's when you start turning the boost higher that you notice a difference in air volumes (as the smaller turbos can't keep up).

i don't know how else to make my point. other than the heat factor i mentioned above, 10 psi is 10 psi. but if your turbo is heating the air too much, again... it's too small for your engine!

what d'ya think? i like turbo-tech... anxious for your reply.

Yeah, I agree about the higher boost portion of the discussion. If you're pushing 25psi out of a Super 16G, you'd probably see a good power difference in using a Super 20G or one of the Frank hyrbids at that same 25psi. Being that the larger turbo wont heat up the air as much.

91 awd: 60-1, 880's, E-Prom, etc.
93 awd: JDM 6 bolt, K&N, full exhaust, Wally 255, otherwise stock.

R.I.P. the original "Factory Freak"
15.5's with short ram and catback only
1996 RS 5-speed

I'd like to simplify our discussion by taking out the variable of different rpm's equalling different boost results and thusly different fuel needs apportioned by the ecu or fpr or whatever. (For now on, we're using boost controllers at wide open throttle...well let's say 6000rpm's )

I know in one sense that it makes a certain amount of "sense" that 10 psi with one turbo would be the same as the next since your boost guage is still saying "10 psi," but I still can't imagine that 10 psi in a T-25 let's say at 6000 rpms compared to a 20g at 10 psi at the same rpm .

Can we agree that if you have more horsepower, then you have more need for fuel? If we can agree to that, then we're both one step closer to where our divergence in opinions arise. Because here's where my point comes in to being: A 20g pounding out 10 psi's of boost is producing more horsepower than any T-25 at 10 psi's of boost. As a matter of fact, I would go so far to venture that a 20G at 5 psi could equal a T-25's hp at 10 psi at the SAME rpm range(if not more).


Example: A Stage 1 420a with a S-16g or T04/03 may have larger compression pistons at 9.6 than a 4g63 with 8.5, but that's not certainly 10 pounds of boost worth of it. Why am I saying that? Well, a Stage 1 420a with NO INTERCOOLER can equal if not surpass easily a 4g63 turbo'ed with a T25 boosting out a high amount of 14.5 psi's of stock boost WITH AN INTERCOOLER. That means the T-25 gets cooler air with an intercooler and approximately 9.5 pounds MORE boost with an intercooler and has maybe less or close to the horsepower that the 420a has with a S-16g/T04/03. (Let's call the 420a higher compression pistons matched with inclusion of the 4g63's intercooler an even wash)

What's the only real variable a I can point out? Turbo size. Again, match me against another 420a, everything else equal, except I have the S-16g and he has the T-25 and we're at the same boost/rpm, I'll be pulling, and I'm positive. Heck, give him 5 more lbs. of boost, and I'll still be passing.

So, the higher horsepower here achieved will require more fuel to facilitate it. Thus, 1 pound of boost with one turbo is a different amount of boost than with another turbo. Although your boost guage says 1 pound of boost, it interprets it in ways we dont exactly know differently from turbo to turbo. The variable of the speed of the boost and volume of the boost has a lot do with this b/c of each turbo's different capabilites.


Jason
98' Eagle Talon ESi-T
Mitsu Super 16g Turbo(HRC)


http://springfielddsm.homestead.com/JasonsPics.html

_____________________________________
Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)

heh... this is gettin good

ok, let's limit this discussion to a "boost controlled" 10 PSI at 6000 RPMs.


>>>"Can we agree that if you have more horsepower, then you have more need for fuel? If we can agree to that, then we're both one step closer to where our divergence in opinions arise. Because here's where my point comes in to being: A 20g pounding out 10 psi's of boost is producing more horsepower than any T-25 at 10 psi's of boost. As a matter of fact, I would go so far to venture that a 20G at 5 psi could equal a T-25's hp at 10 psi at the SAME rpm range(if not more)."

yes, if you have more HP, you need more fuel.

the only reasons that a 20g would be pushing more HP at 10 psi @ 6000 rpms than a t-25 is because if you chose the t-25 for that job, you made a poor choice. a better choice would probably be a 14b or 16g, but we really shouldn't get into that.

the difference in the turbine and compressor wheels efficiency and how they respond, and how the engine responds to them (turbine wheels create back-pressure in the cylinders causing them to not empty completely) WILL make a difference and then there WILL be a difference in fuel requirements. again, there is also the heating of the intake charge by a compressor that's too small for what you're trying to do with it... and by having a hotter intake air charge you'll need to richen the mixture to prevent detonation. if that's the case, you should have chosen a turbo that more closely matches the boost/rpm you intended to run. for the above <10psi@6000rpm> application the difference between a 14b and a 16g would be trivial and you could use the same injector size/fuel pressure on both and let the ECU take it from there.

i guess all i'm trying to say is that if we're talking about 2 turbos that are close to a correct match for the intended use, then any differences will be so minimal as to not be a concern. but if we're comparing 2 grossly mis-matched turbos like a t-25 and a s20g , then yeah, we're gonna see major tuning differences and fuel requirements.

in that respect, you're right. 1 lb of boost is NOT the same for those 2 turbos.

"that's all i have to say about that"... Forrest Gump