Aftermarket EFI

[CyberSniper]

bump the fuel pressure and that all changes...



were can you get 200 lb injectors? that is Way more than you need for 325 hp. How do you figure a 670 or 750 cfm tbi with 200 lbs injectors only supports 325 hp? cfm isn't holding it back... carbs that flow 500 cfm can make 350 hp with a little tuning and the right setup.

I'm not going to dig up the links again. 200lb/hr injectors cost a couple hundred bucks. Doesn't matter because a TBI220 throttle body can't flow enough air for 200lb/hr injectors plus if it could you'd have low-RPM problems. You need an aftermarket (Holley) TBI to get more air and it's got four pods so you just run the cheaper 100lb/hr injectors. If you read carefully you'll find that I said two 100lb/hr injectors are good for about 325hp.

holley has the injector/hp chart on their website...the 670 cfm tbi has 2 85 pph injectors. that comes out to 360 hp.

Is it in Holley's best interest to tell you theoretical results or realistic ones? 100lb/hr injectors (used in the early 454SS's) run at 90% duty cycle flow 90lb/hr. Which is enough fuel, in theory, to suport 360hp. In reality, you don't get that. Not to mention running an injector at 90% duty cycle is taxing them. 100% and you'll burn up the coils.

they tell you to run stock psi because they want you to say damn, i need a 4bbl. then you go and spend 1000 on a 4bbl setup and they laugh their asses off.

Yeap. Running TBI220 injectors at more than 16.5psi is hard on them. At 20psi expect leakage with time.

I am running an inline 45 psi pump.... because of the regulator in the tbi its probably more around 35 psi but i need to hook up my guage.

Great idea. You'll probably find that the injectors leak.

Holley reps are quoted saying that it will support 350 hp...

plenty of guys over at thirdgen have the holley 670 cfm 2bbl tbi with 85 pph injectors and have the dyno sheets to prove their numbers of 375 up to 400.

670 cfm and 2 85 pph injectors is plenty. When i get the sheets you'll definetly see em posted up.

Great, exceed the duty cycle. It promotes long life and dependability. A bigblock TBI220 flows more air than the inexpensive injectors you can buy. Once you get to huge injectors you run into low-RPM problems because the injectors are pulsing so much.

 

[dirtwarrior17]

I had problems at first but i think the computer made some minor changes and now it idles and comes off idle real good...


the injectors don't leak and i don't really care if they do in the future because they are only like 50 bucks for two of em.

670 cfm is Plenty for 400 hp. 2 85 pph injectors is 170 pph total, that is twice as much as the stock tbi's injectors and the holley flows another 330 cfm.

I don't feel like arguing... if you want to see where i got all this head over to thirdgen.com.

 

[Fierospeeder]

Great, exceed the duty cycle. It promotes long life and dependability. A bigblock TBI220 flows more air than the inexpensive injectors you can buy. Once you get to huge injectors you run into low-RPM problems because the injectors are pulsing so much.

i know cyber knows what he is talking about. He used the term "duty cycle"

 

[1CIDMAN]

Go to thirdgen.org and start reading everything on the TPI and similar boards. You really need to figure out what making 400HP with TPI takes from real world experience.

That place seems a little sketchy to me. The guy isn't here to defend himself, but just looking at the vortec manifold pictures, I see a few "problems", even if those aren't the finished product.

Other than that, the rest of the stuff looks like stock GM TPI with siamesed/larger diameter runners, different fuel rails (due solely to the larger runners?) and then some larger injectors and a free chip burn.

You should be able to pick up stock TPI (complete) for $500. Used components, so figure what that is worth to you to get all new sensors, etc., but that's not ("starting at") $1900.

That setup doesn't look to me like it will be enough to make 400HP. Maybe with a good set of heads you can do it, but like I say, go to thirdgen, as there are people there that know what it takes to get there, because they've done it.

WHAT KIND OF "PROBLEMS" DO YOU SEE WITH THEIR VORTEC BASE? IF YOU GO TO FAST-AUTOS.NET THERE IS A 91 VECTOR THAT CLAIMS TO HAVE 650 HORSE WITH THIS FIRST MANIFOLD, SO I DO NOT SEE 400 HORSE BEING A PROBLEM ON THE MANIFOLD END. I KNOW THAT THERE HAS BEEN QUITE A FEW THREADS ON THIRDGEN ABOUT THESE INTAKES AND THEY SEEM TO DO WELL. ACCORDING TO THEIR WEB PAGE YOU CAN GET EVERYTHING YOU NEED FOR $1950 THAT DOES NOT SEEM BAD FOR A COMPLETE SET UP. I SEE THE SIMILARITIES TO THE GM, BUT YOU CAN SEE IT REALLY IS NOTHING LIKE THE GM, YOU CANNOT USE ANY GM PARTS WITH THIS MANIFOLD EXCEPT THE SENSORS.

 

[CyberSniper]

WHAT KIND OF "PROBLEMS" DO YOU SEE WITH THEIR VORTEC BASE? IF YOU GO TO FAST-AUTOS.NET THERE IS A 91 VECTOR THAT CLAIMS TO HAVE 650 HORSE WITH THIS FIRST MANIFOLD, SO I DO NOT SEE 400 HORSE BEING A PROBLEM ON THE MANIFOLD END. I KNOW THAT THERE HAS BEEN QUITE A FEW THREADS ON THIRDGEN ABOUT THESE INTAKES AND THEY SEEM TO DO WELL. ACCORDING TO THEIR WEB PAGE YOU CAN GET EVERYTHING YOU NEED FOR $1950 THAT DOES NOT SEEM BAD FOR A COMPLETE SET UP. I SEE THE SIMILARITIES TO THE GM, BUT YOU CAN SEE IT REALLY IS NOTHING LIKE THE GM, YOU CANNOT USE ANY GM PARTS WITH THIS MANIFOLD EXCEPT THE SENSORS.

Are you trolling?

 

[1CIDMAN]

Are you trolling?

TROLLING FOR WHAT? JUST LOOKING FOR OTHER OPINIONS AND FACTS.

 

[dyeager535]

I think they've added pictures since I commented on it, either that or I missed some of them the first time. The intakes look ok to me at this point, but still don't have a finished product up on the linked page. If there is, I don't see it.

If people are running them, I guess there can't be any major problems with them!