Latest dyno graph...

[HIGHMILEHATCH]

Here is my latest dyno graph:



S14 SR, stock block, head, IM, turbo, mafs, pump gas, 600cc injectors, power fc, the usual bolts ons. Profec b would hit 18 psi, then fall to 15 psi and hold til redline. I'm thinking the actuator just cant hold open at that boost level. Would one of those actuators from HKS do the trick? Big thanks to Jeff Evans of Evans-tuning. Damn I love small turbos with killer powerbands.

[S14DB]

What dyno is that?

[Chillaxed 240sx]

*whistle* ... nice ... I can't wait until my car is suckin air through a turbo.

[HIGHMILEHATCH]

I think its a dynapack dynomometer evolution 3000. But don't quote me on that.

[RBS14]

what's up with the stock turbo and 600cc injectors? what makes you think you need injectors that huge for 15psi on stock turbo? 480's would have been fine.

[s156spd]

Originally Posted by RBS14

what's up with the stock turbo and 600cc injectors? what makes you think you need injectors that huge for 15psi on stock turbo? 480's would have been fine.

why not?

[HIGHMILEHATCH]

Originally Posted by RBS14

what's up with the stock turbo and 600cc injectors? what makes you think you need injectors that huge for 15psi on stock turbo? 480's would have been fine.

Gee, I dont know. Obvious reasons I guess. Ever hear of engine management? Maybe because I like running 43% duty cycle at 15 psi rather than 92%??? Maybe the car still drives and idles like it's on stock injectors, but I have plenty of injector left for a future turbo upgrade??? Maybe it's a margin of safety to be able to dump fuel incase of a boost spike??? Maybe there is no question as to whether I have enough fuel on tap for this much power on the stock turbo??? Why would I install 480cc injectors when I'd just have to swap them again sooner or later??? I didn't know 600cc was considered "huge". Can you give me any reason NOT to upgrade to larger injectors when you have full control over any size via standalone? Please enlighten me of the disadvantages of running larger injectors. I'd love to know what you based your statement on.

[97DubTruck]

Originally Posted by HIGHMILEHATCH

Gee, I dont know. Obvious reasons I guess. Ever hear of engine management? Maybe because I like running 43% duty cycle at 15 psi rather than 92%??? Maybe the car still drives and idles like it's on stock injectors, but I have plenty of injector left for a future turbo upgrade??? Maybe it's a margin of safety to be able to dump fuel incase of a boost spike??? Maybe there is no question as to whether I have enough fuel on tap for this much power on the stock turbo??? Why would I install 480cc injectors when I'd just have to swap them again sooner or later??? I didn't know 600cc was considered "huge". Can you give me any reason NOT to upgrade to larger injectors when you have full control over any size via standalone? Please enlighten me of the disadvantages of running larger injectors. I'd love to know what you based your statement on.

Really good idea to have the power fc and larger injectors right off the bat. I should have done that and gone without random other shit. Now i want injectors and have no money. Beautiful powerband and great numbers out of the t28.

[HIGHMILEHATCH]

Thanks for the compliments DubTruck. By the way, your car looks great in that link. Clean and simple.

[nlzmo400r]

I think what RBS14 was getting at, is that usually a car with injectors that properly match the turbo makes the car idle/run better. Using injectors at 90percent duty cycle is better than running bigger injectors at only 55percent duty cycle. Thats all he's saying, and technically he's right, however the fact that you have the power FC and hte ability to tune air/fuel and timing, all but eliminates the problem with injectors that are 'too large for the turbo'. Nice setup either way, and what a powerband for a t28

[sr240mike]

Are you sure you know what you are talking about? I've seen large injectors run just fine at idle and under light acceleration, its all about the tuning of them. Its recomended by most injector manufacturers to not even run over 85% of duty cycle. Having those larger injectors is smart in planning for future power upgrades.

[HIGHMILEHATCH]

Originally Posted by nlzmo400r

I think what RBS14 was getting at, is that usually a car with injectors that properly match the turbo makes the car idle/run better. Using injectors at 90percent duty cycle is better than running bigger injectors at only 55percent duty cycle. Thats all he's saying, and technically he's right, however the fact that you have the power FC and hte ability to tune air/fuel and timing, all but eliminates the problem with injectors that are 'too large for the turbo'. Nice setup either way, and what a powerband for a t28

Sizing an injector based on the projected power output has nothing to do with how the car idles/runs. It doesn't matter what size they are; if the tuning is not on par, no injector will make a difference in the idle or driveability. You can tune the car on 370s or 860s and make it run great, or like garbage depending how you tune it. The only difference is, my engine has enough fuel to support roughly 400 hp provided I have a turbo that can flow enough air. I like having plenty of fuel on tap no matter how much power I plan to make. It gives me the opportunity to run the A/F rich enough under boost to cool the combustion temps, keeping the tune plenty safe, which yeilds reliable hp. This to me is very important particularly with stock bottom ends. I disagree that running an injector at 90% duty cycle is better than 55%. Technically RBS14 is not right. Running them that high runs of risk of the injectors going static, locking up, and leaning out in that particular cylinder. Not what I want happening. Thanks for the compliment about the setup.

[WILDACEX187]

can anybody answer his first question about the actuator, im interested in the answer. nice set up btw any pix of engine bay/car?

[RBS14]

I guess I should have asked for an a/f ratio graph for that dyno pull. do you have one? I was wondering why you had such large injectors for such a stock setup. With them being the only big mechanical upgrade on the engine, I thought that maybe you had been told by someone that you needed injectors that big for higher boost. If you really intend on hitting 400hp, they are great. But I think it's overkill for what you have now. And it's not like they are gonna save your motor if/when you boost spike.

Also, there's no need to come off like such a dick. It was a valid question. "ever hear of engine management?" yea, I'm putting together a megasquirt for my car, way more hectic than your pfc. But this isn't a pissing contest, so i'll stop. Try to take the stick out of your ass and answer people's questions in a civil manner.

[89s132b]

LOL - PFC is a piggyback???? That is funny.

Glad to hear you like the injectors. Tell your friends

[Drunk Bastard]

great dyno! what were your air:fuel ratio's?

[HIGHMILEHATCH]

RBS14, your question sounded a little condescending. That is why I reacted the way I did. No hard feelings. Air fuel was between 12.0 to 11.5 depending on the load. Cruising range was as lean as 16.0. I'm done with the engine for now. Need to do something about the stock brakes and suspension.

[RBS14]

cool, no hard feelings here either. Internet is hard to distinguish tone sometimes. Not bad a/f's except for the cruising. yikes!