seanof30306

iTrader: (4)

http://www.gtoracing.com/automotive/...d/throttle.asp

i can't find that on holley's website anywhere. does anyone know anything about it/have experience with it?

RBob

iTrader: (1)

This link lists most (all?) of the Holley EFI parts. It includes the throttle bodies.

http://www.holley.com/HiOctn/ProdLin...IA/FMSFIA.html

This is a link directly to the 900 CFM 4BBL TBI:

http://www.holley.com/HiOctn/ProdLin...A/500-16S.html

Price's are competitive to a new carb too.

RBob.

gordo

will this work with the factory computer,assuming a custom chip is added? I am building a big inch smallblock and would like to retain the looks of the lo3.

JoBy

You need two additional injector drivers.

Read this thread:
https://www.thirdgen.org/techbb2/sho...hreadid=154902

RBob

iTrader: (1)

Yes to what Joby says, need two additional drivers.

There are two ways to do this. One is to add the two drivers internal to the ECM. The second method is to add an external driver box. Both are accepted practices. Just pick the one that suits your talents/requirements/needs and go with it.

This will work.

There are the National Semiconductor (www.national.com) LM1949 and then the OnSemi, used to be Cherry, CS-453 5-pin To-220 cased device.

I'd really like to see someone do this. On the DIY-PROM board a guy YELLOWBB(?) has done this. He isn't finished tuning yet, but it is working out for him. He is using a '747 w/an external driver box.

RBob.

JPrevost

The only reason I'm reluctant to go witht he 4 barrel TBI is the injectors. I was under the impression that they used the crappy injectors still. I've been getting better with solid works and the plan is to make my own injector pod that housed GM injectors.
Tough project.

RBob

iTrader: (1)

Don't know. I had thought they were the newer Delphi injectors. If they are the older ones then I wouldn't use it either.

The pictures do show the black plastic caps. I think that means that they are the old style. Oh well.

RBob.

RBob

iTrader: (1)

Just got it on good word. The Holley 4BBL TBI's also use the Delphi injectors. These are the 'good' ones. Holley has been using these for 2-3 years now.

I would use one of these TBI's.

RBob.

JPrevost

Cool! Then forget going to port injection.

ben73

Why are these injectors crappy, and are the black caps a sure way to identify them?
I dug up this old post while searching on holley 900 4bbl stuff ;-)
Ben.

r90camarors

Yes, the black caps indicate the old mopar style injector. Those injectors have a bad rep, seems mostly due to a short life span and poor spray patterns from what I have read.
The only experiance I have ever had with them were on my father's '89 ram, which came stock with a holley tbi (though the injector pod sits down much farther than the 670). Anyways, at 2XX,XXX miles, one finally went bad. But I'm not sure if they are exactly the same as the ones on the 4bbl tbi.
The Delphi's are possibly able to handle a 100psi, I'm not too sure about that, but someone stated that in a post a couple of weeks ago.

The other reason to go with a 4bbl tbi w/ the delphi's is that the unit also uses progressive linkage, which of course is a good thing given a way to tune it in. Maybe a tps % toggle to the external injector driver?

Also, the delphis use a side mount connector and no black caps, just for reference

IROCaholic

I ran one of these 4bbl throttle bodies on my 350 when it was still TBI for about 2 months, but I only used two injectors since they were 65lb and plenty for my bolt on 350. It worked great, but I was at the point where I needed some tuning in order to revv in the higher RPMs so I ditched it for a carb and added some more goodies to my engine. I actually still have the Throttle body, I tried to sell it for like $200 a while ago and nobody wanted it. I would defenetly reccomend it to anyone who is building anything bigger than a 305 and keeping it TBI.

r90camarors

With the right tuning, a holley 2bbl tbi will work wonders on any street driven 350 pushing out up to 400hp. Though I can only imagine how much easier it would be to tune in a 4bbl tbi w/ commander 950 on a high hp engine.