I have maxed out the injectors that came with my Greddy TT (440cc) and I need to go to 550 or so. I'm not really sure why the kit comes with 440 because, if you do the math for 400 hp on our engines, clearly over 500 cc/min is required. Anyway, the graphs don't lie, I need to swap but I don't know what make of injectors come with the kit. I know the TT installer had to put in new connectors for the 440 cc injectors and I want to get 550s that have the same plug.

Has anyone swapped out their Greddy injectors with something else? What did you get and did you have to replace the connectors?

 

fyi, most people, including greddy will tell you 380whp is the most you want put out on a stock motor. the 440's in the kit are good for greddy's intended purpose on a stock motor. i run the rc750's. my shop bought clips for them, but i'm not sure where they got them from. pushing 400 plus on a stock motor isnt a good idea. i ran my stock setup for about a year at 420whp with no issues, but i already had it in my mind and wallet that i was gonna build the motor.

 

I'm only pushing about 350 and things start leaning out at 4900 RPM. I need bigger injectors just to get to 400. My car is a little different than most... I think I'm the only one that has gone FI and piped up about the different ECU plug so far. There may be other little differences in the car that make the bigger injectors necessary, but after doing the injector math, I'm surprised people are able to get 400 hp out of the 440cc injectors.

 

Do you have a walbro pump? you shouldnt be maxing out your injectors. I get 408hp with 440 and still got room to play.

The greddy kit comes with RC injectors so if you get any RC you should be fine with the same clips. I just bought 550cc and they work with the 440 clips

 

/\ You are fine in Cali with your 440 but in Canada that might be not enough coz they consume more fuel especially below freezing.

 

I've been at ~450whp with my 440's and greddy kit for the last few months. I got 405/399 with my kit at ~80% on my 440's. Do you have a return kit?

Motor is being built right now and going with 650's.

 

I am using a Walbro 255. It could be that the temperature here is the problem. You guys are cruising in nice 80+ weather and I'm at 40 or less. I know I'm maxing out the injectors because I have a pretty good graph from the E-Ultimate showing 100% duty cycle and the A/F starts to rise after 4900 RPM. I don't think a fuel return system would help if the injectors can't take any more.

Thanks for the info on the RC injectors!

 

still doesnt seem right. i was at 420whp on my old aps single setup. with their injectors i was at 90 percent( which aps said was safe). their injectors are listed at 440cc, but i think but aps uses a higher base pressure. they were prob more like 380's. i know it has been debated to no end, but i just prefer to have a return system on any f/i setup. eases my mind.

 

We use Deatsch Werk injectors on all of our cars and have no problems whatever so ever. And make a little over 400 on the stock block . Let me know if you're interested in some deatsch werks

 

Check this thread, look like 400 is pushing it if you just have the walbro.

http://www.my350z.com/forum/showthread.php?t=315556

 

I live in Phoenix but spend a lot of time up in Prescott (5200 ft) and cold. I have driven my car at <10 degrees a number of times this winter with no issues.

 

Don't you have a return fuel system now Tim?