so i am learning the whole concept of forced induction tuning... i got the basic essentials of tuning (such as exhaust and intake) down, but i don't know much about injectors.

my goal is to hit 500~599 rwhp range. right now i have an APS TT, a basic built block with wiseco 8.5 cr and GTM rods all controlled by UTec... i am hitting 400 rwhp and i WANT MORE, dammit.

so what's the secret formula? 1 cc of injector capacity per 1 whp? also, since i am using a tuning ecu... is the injector a plug-n-play system then set it n' forget it or must i "program" the UTec to utilize these injectors? lastly out of educational value, why is an injector duty cycle capped at 80%? so, if i want to hit my goal, do i look at 650 cc injectors (650 x 80% = 520 hp?) or at the 550 cc injectors?

i am also told the APS actuators have to be scrapped in favor of actuators (such as forge) with stiffer springs. has anyone installed these actuators while the turbos are still in the car? is it even feasible or must i bust some knuckles again to remove those snails from hell?

thank you for your time.

 

I would just get the APS Extreme fuel system and be done with any fuel concerns.

I would get 12 lb or higher springs. I have 10 lb forge actuators paired with the 3.5" test pipes and 2.5" APS exhaust and I could make 17 psi peak tapering to 14 lbs at redline. This equated to 520-something hp and 550+ tq. To go higher, I need stronger actuators.

 

you will need a fuel return kit this one is by far the best one I think, and the one that Im have in my basement!
http://cj-motorsports.com/prod350fuel1.htm
I will be using the forged actuators, do a search for them they are a hot topic, this is were to get them and the guy you should talk to is Sharif
http://cj-motorsports.com/prod350fuel1.htm

 

are those the yellow springs 9-15psi??

 

http://www.************************/...fss09/fuel.htm
looking at the specs of the injectors... i THINK 880 cc seems to be overkill for my application. twin fuel pumps??? goodness gracious~~ have you installed those actuators yourself?

the APS TT comes with a fuel return system. i think the limiting factors are the 440 cc injectors that come with the kit and some good ol' tuning.

thanks for the replies guys.. keep them coming!

 

the APS fuel system will support upto 450 whp then you'll need to upgrade to a true fuel system like the CJM or AAM.

 

if you upgrade the injectors you can run 450-475, but you will be maxed there. The restriction is in the lines back by the tank. The feed for the rails is rather restrictive as well. If you choose to push the fuel system on your car harder with just larger injectors, I would recommend at least comparing fuel pressure at the inlet of the passenger rail and after the last injector in the drivers rail. This is because the restrictive entry into the rails could be starving the rails from being able to maintain equal pressure after each injector has had its take of fuel.

your range of HP given will effect what you need to do to the fuel system. If you can live with 500, you can squeeze by with the some larger injectors (660s probably the best idea), and a standard fuel return system like the one mentioned above. But if you want 600, it starts to get more difficult to get that out of one walbro pump and will require extra measures and a slightly more expensive system. Much over 600 and twin pumps are almost mandetory (tho a few guys have made it to 650 and a few over with a single pump at the limit). So try and figure out what you want, and assume you will want at least 50 more down the road. If you going for 500 or just over it, twin pumps would be retarded of course, but if you think you are gonna keep pushing for more and more, then you might need it.

You could get the same injectors as that APS fuel system, they are actually only 620cc anyway.. but they are a little shorter and I am not sure they would fit the stock rails without some sort of injector spacer - but they are extremely cheap at about $360 a set + clips. Most guys here have been using the RC Injectors, and you will find they are carried by the venders on this forum.

As for those actuators, the Forge are the only ones I know of. If you get some, you might ask if they have the upgraded diaphrams. Someone on here was saying that they have made the diaphrams thicker now??? If thats true, im assuming because so many people have had problems with those diaphrams tearing later down the road, causing the boost to climb higher and higher as they tear further. And yes, you CAN install these WITHOUT removing the turbos. I have done it, and its not too bad at all. You will need to take the alternator out.

As for the tuning of your UTEC, leave to that professional - there are a few Z tuners that are reputable around here that are in your state.

 

bro you are in socal. talk to Sam at GT Motorsport and he will sort you out.

so did your build and tune. was it GTM?

 

sam did my build and tune. he delivers when he delivers... but, i like to do my own work. i worked on every modification besides the engine build and clutch job as those two includes heavy labor... hell, the APS TT install was a ***** and a half. if the job is not too intensive i'll take it to sam (even though most likely i will), but i posted this thread for my own quench of educational value.

 

sam is a good guy, he will definatly take care of ya!