I'm toying with the thought of upping the boost 2psi. I'm currently seeing 6.6, but am considering upping it to 8.5psi. With just the OEM fuel sys w/ the RC440's and a Walboro 255 lph fp, can I run 8.5psi with a relative margin of fuel system safety in terms of not having a return fuel system w/ a fpr??

 

What EM do you have? If its the one that comes with the kit I wouldnt touch it!

 

8 no more i say to be on the safe side

 

you WILL go lean as hell.

heres the process i went thru a few years ago. mods were just greddy kit, borla duals, kinetix test pipes. thats it. Oh yea, a JWT Clutch and flywheel.

i only ran the car on 100 octane. It ran clean and perfect (aside from rich in boost). Honestly the stock ignition timing is a tad aggressive for 93, but perfect for 100 octane and like 5.5psi or so. it was great, and withstood abuse. The car ran rich off the scale and made 347rwhp. i tried 6 - 6.5 psi... but it would get way too lean on top. This is still with base greddy map, didnt change a thing.

Then I added just the walbro. I was able to run 6.5psi and it would JUST start to go lean at redline. It would hit 12:1 A/F just at redline, which I was ok with since I was on 100 octane. The car made 398rwhp like that. It climbed a ton because the A/F wasnt rich off the scale anymore, so the extra boost SOMEWHAT evened out the tune. Any more boost at all (even .5psi), and it would go too lean and a lot sooner.

Next, I added JUST the return fuel system. I cranked up the fuel pressure a little. STILL on NO timing harness, but still 100 octane. I did a little tuning in the E-Manage on the top end. MINOR adjustment, didnt even touch the midrange where it was rich as hell, just added some fuel on the top end. i was able to run 7-7.3 or some crap psi, and the car made 416 rwhp. When it pulled out of rich off the scale at 5500rpm, it would hit 11.5:1 by redline (6500rpm).

Thats how it was when I raced those Supras in that old *** video that made it allllll over the web. The car also ran a 12.1 in the 1/4 like this, and im a pretty crummy drag racer. I am sure if Alberto or Brian drove it, it would have been 11's already. I was trapping 116 IIRC.

Thats how the car stayed, until I added the FCON, swapped out to CJM return kit, added HKS1000cc injectors, tuned to 467rwhp at 9psi with no other changes until I built the engine.

 

+1

Personally, I would not attempt to raise the boost at all on the Greddy TT kit...even with a Walbro. enjoy it as is...then get a return fuel system, something better for tuning (UTEC or FCON), and they you can safely raise your boost and power levels.

 

Sharif- Is the Emanage very safe for the stock boost levels? I've heard alot of negatives about it lately.

 

I've got the UTEC, thanks for the advice guys! Looks like it's wiser to end up getting the return fuel sys and picking up some 550's before bothering upping the boost.

 

I dont like the eManage blue at all, and the EU is a little bit better. But best bet is the UTEC for stock'ish boost levels.

 

what about with UTEC/ Walbro pump/440 injectors/ CJmotorsport fuel return?

 

just a quick update - we ended up running the car to around 9.5psi, and that's when the injector duty cycle got a lil too much. so it was dialed back to around 9psi, it's now putting out 452whp and 428wtq. Car is running really strong! Eventually the next mods will be getting away from the stock exhuast and going w/ 3" TD, bigger injectors and a return fuel system Car has the 440cc injectors and walboro 255 lph fp for now & UTEC for the brains.

 

i can see into the future, your next thread isnt gonna be good.

JK, be careful with that setup!

 

lol thanks tig, that's part of playing the game. if it goes it goes, if it doesn't its getting rebuilt anyway I'd definitely recommend going return fuel sys and bigger injectors anyway but its interesting to see what it can do with just a relatively stock fuel sys. the afr at 6600 rpm was 11.9 so I don't intend on upping the boost anymore. car was tuned and dyno'd on 91 octane.

 

waw u r probably the strongest in this set up congrats but as u said u r playing the game and a verey dangi dong 1 hope ur engin last u long.

 

how much hp is this setup good for?

 

I'm installing these right now. Plus my tuner pro and oil/plen spacers.

 

About 440whp at 90% duty cycle...depending on your fuel pressure.

 

Is 90% duty cycle pushin it though?

 

It is the max envelope I would push on a customer car. The newer RC injectors use a diferent orifice style, and are engineered to be safe at 90% duty cycle, vs. 80% for most others.

These are just general guidlines for the sake of this discussion. You can run slightly higher fuel pressure, which will result in even lower duty cycles.

Selected a proper injector size, involves some compromises, for a street driven car.

 

Next mods, CJM stage 1, RC 550's, 3" turbo back dump tubes dumping right by the SVRT wastegate dumps to eliminate the exhaust and provide no back pressure and tune to 10psi! Should be fun >:-)

Has anybody had any issues with startup/idle w/ 550cc injectors or will they scale fine w/ the UTEC?

 

Juztin, when you install the CJM fuel system, and hook up the vacuum line to the regulator, you will have a 1:1 fuel pressure ratio. So even if you set your base fuel pressure the same, at idle it will drop a lot due to engine vacuum. This will make it so little to no scaling is needed to idle the 550 over the 440 @ static pressure. However your fuel tuning curve will mostly likely need some reshaping overall.