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My T25 NX is running like a champ and of course the turbo bug has bit me, so I'm upgrading it after having driven it just about a dozen or two times.
The current setup is a 9.5:1 engine, S4 cams, 370's at 4bar, bored DE maf, Walbro 225, Nismo AFPR, Outlaw spacers, t25 on GTiR manifold and J pipe, 3" exhaust, and a Blitz SBC electronic boost controller.
I have a Calum Consult box for datalogging, and a Techtom CMX-100 for day to day playing, so the numbers I'm quoting below are accurate.
At 12psi, I'm pulling 4.94v on the MAF, and I think I was in the high 8x% injectors (84, 87? I forget exactly).
At 15psi, I pulled 5.01v and 91%, which are the same exact numbers Greg Perry did when he put down 262whp on his T28.
Quote:
Originally Posted by GregPerry
"At 10psi of boost (with a momentary spike to 13psi, then falling back down to 10psi quickly), I nailed 263 whp and 243 lb/ft of torque. My Techtom read 91% of the injectors were used on this run. MAF voltage at 5.01v. Niiiice.'
I'm in the middle of upgrading to a T28, with a Spearco FMIC and Hotshot fmic pipe kit, 2" hotside, 2.5" cold side.
I'm concerned about getting so close to maxing out the maf and injectors with the T25, and have a feeling that it's going to limit my T28. Basically, I want some more headoom 'for emergencies'.
So where am I going with this??? What are your thoughts on going up to a Z32 or similar maf and running the 370's at 4.5 (or 5) bar? Keeping the 370's is atractive to me because it allows me to retain the stock fuel rail, and because I'm cheap.
If 370's at 4bar are good for 290whp, what would 4.5bar or 5bar support?
I guess the other option would be to go with sidefeed 440's, or are they 480's?
Those are the 480's injectors I was thinking of. Not a bad price, but if I can get the ECU programmed for 370's at 4.5 or 5 bar, it's $239 I don't need to spend on injectors.
its up to you how far you want to push them. You have to remember that other things require more fuel pressure, ie every pound of boost ups you a lb of fuel pressure. And then decide how much headroom you want...
If your not driving the car that much, id say fu*k it do it. But thats me, I personally have been warned against going too high in fuel pressure.
__________________ Clean a$$ hell red 200sx.
I love my cars, but I'll let you guys keep spending all your money on them. I'm getting a house
You have to remember that other things require more fuel pressure, ie every pound of boost ups you a lb of fuel pressure.
The fuel pressure automatically goes up by 1psi per each pound of boost. I have a Walbro 255 and Nismo AFPR, so the supporting systems are there. The whole key will be how much horsepower 370's will support at the higher fuel pressures.
I know you said you are cheap, and I know how that goes. Do you want to the be pioneer to find out how far they can push the 370's? That might be a good thing or could go wrong too.
If you do it please keep us informed to how far they can be pushed, I figure you can sell your 370's for $100 and then buy the 480's for $240.
That's a good point about it just being a $140 upgrade. I just wonder what, if any are the downsides of running injectors at higher pressures. Nobody to my knowledge has had an issue with the 370's at 4bar. Smarter people than myself will be able to tell me how much power 370's can support at 4.5 and 5 bar.
Given the fact that people like Daveracer are knocking on the door of 320whp with a T28, this would be good info.
Although my input isn't about your problem, David from Deatshwerks is the man. He is local here and only sells great stuff. I've seen his flow bench in the works and it's amazing.
I say upgrade. I wouldn't want to push the limits of those injectors, but that's just me.
__________________ Corey Schwab aka "The Boost Bear."
The walbro flows less the higher you go up in fp. I've got a curve for it and some other pumps buried somewhere. I agree with everyone else, go up in injector size, and run your new injectors at 4-bar, but with your wideband you should be able to tell if the walbro can't keep up with 4.5-bar.
For the maf, if your only planning on ~300hp tops you might look at the early 90s maxima maf (pn 22680-16V00, purple tag, N60). Its physically the same as a Z32 and uses the same plug, so upgrading later to the Z32 is easy. That and they're waaaaay cheaper than a Z32. Nate got me hooked on these things.
No wideband here Calum, so that kills that idea. I'm surprised to hear the Walbro would have a hard time maintaining 4.5bar. If that's the case, it's Game Over for that idea, and onto 480's.
Killdanow, thanks for the chart, but I don't understand it. Does anyone know how much HP 370's will support at 4.5bar?
Thats what I was looking for. Thats one of the best write-ups on fuel pumps I've ever seen. Note when they're talking about max injector size they assume your using 6 injectors.
No wideband here Calum, so that kills that idea. I'm surprised to hear the Walbro would have a hard time maintaining 4.5bar. If that's the case, it's Game Over for that idea, and onto 480's.
Killdanow, thanks for the chart, but I don't understand it. Does anyone know how much HP 370's will support at 4.5bar?
C
@ 5 bar they should do 325 - 350. However you just read the same article I just read and it says that after 60 psi the fuel pump relief seeps off some of the pressure. Id just buy the bigger ones and run at 4 bar knowing that. 140 bucks is indeed a very cheap mod, compared to what alot of us has dropped in moments on our cars.
I'm assuming Chris is running the 255HP (GSS342), which should support 60psi+. No data for that pump, but I'd assume you can use the regular 255 (GSS341) for a ballpark.
Yea, sometimes it isn't worth being a cheapskate. :p
Black '95 200sx SE-R Turbo Lowport 286whp/245wtq 12.306 @ 113.55
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Quote:
Originally Posted by BORNGEARHEAD
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