View Full Version : 10 psi t4 ka24de with a fmu

05-14-2003, 10:42 PM
i have a 95 ka24de in a s14 im running 6.5 psi of boost on a t4 with .60 on the compressor and .68 on the turbine i have a vortech fmu i was wondering what you guys think of me upping the boost to 10 psi and adding a additional injector one of those cold start injectors off a older volkswagon as of now my motor is running at about 1200 degrees egt when im boosting no problems so far ive had this setup for about 2-3 months no problems at allso what do you think ??

05-14-2003, 10:45 PM
i was also wondering which plugs you guys would reccomend as of now im running bosch platinum 4's but they burn to hot

05-14-2003, 10:51 PM
ghetto.. boom...
btw, that was one h3ll of a long sentence.

05-14-2003, 10:56 PM
what makes you think itll boom?
any experience?

05-14-2003, 11:01 PM
i mean whats 3 more psi if im already running way rich when im boosting and i have that cold start injector just to be safe if the motor booms i have a fully built ka waiting guess im just curious to see what i can get away with kinda want this to last a couple months more though any one else have any input

05-14-2003, 11:46 PM
IIRC it's almost unsafe to run that much fuel pressure...

Do you have a stock pump? Hopefully not.

05-14-2003, 11:53 PM
Only if you get 370cc injectors should you do this. 10+ is over an fmu's head.


05-15-2003, 12:03 AM
Yeah you can do it, but you need to have a good fuel pump anyway, that's a given. You could do it with AFC/FMU/370cc. For the FMU you'd probably want 6 or 8:1 rather than the 12:1 that comes with most kits. 10 PSI on stock injectors and an FMU is asking for trouble.

ruff ryders
05-15-2003, 01:42 AM
I've run 10psi on my set up with no problems. Same set as you have except with a BEGI FMU, t3/t4, and a 255 walboro (which i'm sure you already have). I have the timing at 17 degrees BTDC and my EGT's read no higher than 1500F at full boost redlining fourth gear. My A/F gauge reads just inside rich throughout the entire time. No pinging or knocking either. Hopefully that helps you some

05-15-2003, 07:10 AM
i do have the walbro 255 high pressure and as of now my egt's run at 1200 at full boost i think im gonna try to increase it gradually see how far i can go not past 10 though ill let you guys know what happens also does any one have plug reccomendations thanks- Joe

05-15-2003, 08:46 AM
FYI, your EGT's aren't going to save your butt if its lean. If you don't have any idea what your EGT's read on a dyno in relation to your AF, you will blow that motor up. You would need at least 2 or 3 degrees of timing pulled out, some type of high flow pump, and a set of 370's and a AFC to do it at least 1/2 assed correctly.

The pump will probably be ok, however the stock fuel rail and stock injectors won't support but about 189 flywheel HP at 43.5psi, so with rasied pressure you can get upwards in the 250HP range. 10psi on a KA should net about 260RWHP, thus about 300 crank, the stock injectors if they even support it, won't do it long as they will be well past 85% duty cycle.........one could seize up.....lots of stuff could go wrong, and I wouldn't chance running 100+psi fuel pressure(as will have too) just to get more boost.

Take it from someone that has seen it all the time, spend some money get a better timing a fuel management setup, otherwise you'll have to waste money building a KA after you pop one.

PS... great article about how EGT's relate to AF

ruff ryders
05-15-2003, 12:38 PM
I was under the impression that if the stock ECU is still being used to run the stock injectors, you will be running stock duty cycle with increased fuel pressure being pushed through. Also, Just for reference, on the dyno last weekend my car put down 200wph at 5500 feet (uncorrected) and like 246whp (corrected) at 10psi on pump gas with A/F reading 11.2 on the wideband (rich as a MF).

05-15-2003, 03:33 PM
That would be even worse. Your injectors are going to work in a range from 0% to 100%, and that varies with RPM. I personally don't know what range Nissan runs their duty cycles in based on RPM, I have seen some cars at WOT running 80%+, but most do it at 43.5psi of fuel pressure. Now take into account you guys are running 100+psi of fuel pressure at the same duty cycle, possibly more , then you eventually will reach the point where the injector will fail, or even the pump.

Your corrected HP is about right for 10psi on a KA, I would however be curious to see your AF all the way across the RPM band, FMU's typically run out of steam up top. and my bet is you are getting really close to the limit. 11.2 is pretty rich, and your high flow pump is helping out a bit, but you are just playing a dangerous game with high fuel pressure, I personally wouldn't chance it.

ruff ryders
05-15-2003, 03:53 PM
i agree...You have some pretty good points, I pretty much know that my set up pushing the limits. It's just temporary for now. I typically run about 8psi daily on the street. I'm ditching the FMU for a haltech E6K w/72lb injectors. I've had it sittin in my room for a while, we're just trying to figure out the distibutor wiring part of it. It'll be interesting to see what this produces hp-wise and 1/4 mile-wise too. http://forums.freshalloy.com/images/graemlins/grin.gif Thanks for the info...hopefully this helps the guy who made the original post.

05-15-2003, 03:59 PM
I recently helped tune my buddies FE3 probe motor with his SDS setup. Running 780cc injectors and such. We made 400FWHP on a 2.0L and 385 in torque at 23psi. He's only at 70% duty cycle now, his boost controller is maxed out LOL.

I would be figuring with no timing management other than base timing removed, 10psi is probably the max on the FMU. You should be able to get the car in the 13's with a good driver.

My buddies probe traps at 125MPH, but can't get out of the 13's....talk about hard to drive.