I have a Comptech SC and am waiting the arrival of my e-manage. My question is running stock boost and no Aftercooler do I need to upgrade my injectors? Can the stock injectors supply enough fuel? I was considering buying RC 550 injectors. I will be adding an AC in the future.

Thanks

 

You need to check your AFR. If you are running lean, I would get the bigger injectors just to be safe.

 

If you got the complete Comptech S/C kit, you should be fine. It is sold as a bolt on and unlike some Vortech kits, the Comptech kits of the last few months have been shown to run just a bit on the rich side. Many, many Comptech owners have been running the kits as a straight bolt on for years with no further tuning and have had no issues. Once you get the new ECU, then you can do some tuning. You may not even need bigger injectors unless you start to tweak it for more HP.

 

As you are boosted you need more fuel. The Comptech does this by increasing fuel presure proportionally to boost pressure (the FPR). A little bit ghetto, but effective nonetheless.

The nice thing about the E-manage is that it can control fuel both my altering the MAP signal (a la V-AFC) and by directly driving the injectors. So if you want to you can remove the remove the Comptech FPR and just increase the duty cycle of the injectors to supply more fuel. Of course whether or not the injectors have enough duty cycle left for the amount of fuel required tells you whether or not you need bigger injectors.

If you use bigger injectors you enter the old and new sizes in the E-manage and it calculates the difference and alters the MAP signal accordingly. Of course drastic changes of injector size result in huge MAP signal differences and can lead to unexpected results. So Greddy recommend only increasing injector size to 150% or original.

My choice was to remove the FPR and use a SARD unit. It's still rising rate, but not as drastic as the Comptech. I then used the E-manage and 440cc injectors. I chose 440cc because they could provide enough fuel at full boost whilst fitting in within the E-manage's suggested 150% rule.

The E-manage you purchased from me is actually set up for this configuration at present.

 

I thought RC 440's were low impedence and there for were not s2000 friendly.

 

Nope and nope!

There was a time when you couldn't get anything higher than 550s in high impedance IIRC but 440s have been available for ages.

 

Now if I plan on adding UR 500cc injectors w/ the comptech s/c kit, do I need a aftermarket FPR? I would at least remove the comptech FMU right?

I'm just trying to figure out what is all needed - btw I'm running the e-manage. Thanks!

 

If you switch to 550's, remove the FMU. you don't need it. You may need a adjustable regulator to adjust static fuel pressure. I'm using the max reccomended static fuel pressure with the 440's, at 55 psi static. I could switch to 550's, and run lower pressure and reduce the additional duty cycle that the 440's are requiring.