Should I think about getting a higher flowing TB unit? I did the ultimate TBI mods already to this tb and did the afpr and injector spacer but it still feel sluggish around 4000-4500rpms. Do u think I would just need to upgrade my injectors or to a 454 TB unit after the cam and intake swap? I don't have any head work to the engine but I do have a full 3" exhaust system, no cat and Edelbrock TES Headers with the 3" collector. So I am gonna get all the power I can from that LT1 cam so it will be pusing my motor for air pretty bad and fuel.

 

Whats the point of swaping the intake if you aren't gonna swap the TB?

The 2" diameter of the TB openings will help quite a lot and you will really realize the potential of the engine At least, until you do heads.

 

or...bore the stock TBI unit out to 48mm and use the stock TPI throttle blades. This is pretty close to 2" inches (50.8mm)

 

I don't think it's time for a bigger tb just yet. You might look at you advance curve. You could be having some timing taken out by the ecm due to preignition or you could be running a little lean. Do you have access to a scan tool or winaldl? This would help you find the trouble faster and keep you from making unessasary changes that might make matters worst.

Steve

 

Well I don't want to do it if its gonna be an overkill, thats why I am asking. Of course it will flow better and blah blah but do I need it? I have the Windal software but I haven't bought the cable yet (I got it for 29 bucks, I am lazy. )

 

I think the ultimated TBI will be fine. I think the swirl port heads will be the restriction at that point.

 

:lala:

 

LoL, the guy can't use his keyboard so I have to read picture langauge. Lets see. That must be Taz looking at my throttle body and then his dance must mean everything is ok and then thats him waving goodbye and peeling out in his car. How did I do Taz?

 

 

91Bird305,

I've said it before and I'll say it again. I have the stock intake manifold and cam (unfortuantly), with my only real mods being a very strong ignition setup, open element, and full exhaust. My origional TBI injectors were going bad, and I found for the price, the holley 670 to be a good deal. I bought the 502-5 w/ 57lbs injectors. And it works GREAT!!! No questions asked. Nice SOTP.
So when people tell you not to go with the 2" TBI, realize that the extra air does help, just be careful when matching your injectors.

 

Hmm, maybe I should look into a 454 TB unit then. Then get my injectors flow matched at this local place....

 

ISERCASTiK@aol.com Jeremy might have a 454 TBI for you. He got one for Pablo. I got some '99 Camaro seats from him 2 weeks ago.

 

drooooool......leather?

 

oh yeah i would go with a larger TB

 

Can anyone give me some info on the 454 TB units? Like cfm rate, injector sizes, etc... thanks.

 

nah. I'm gonna test fit my old seats in my Jeep. If they fit in the Jeep I might put these gray cloth '99 seats in there and get leathers for the firebird.

 

91, the GM 454tbi is rated the same as the Holley 670cfm tbi and come with either 80# or 90# injectors.

Steve

 

and i think they have different throttle mounting plates. ask snuf

 

Don't they come with 65lb injectors too?

 

nope i think only 90 something lb/hr injectors

 

The Holley 670 (502-6) comes with the 65 lb injectors. The 502-5 comes with 57 lb injectors. The 454 TBI I believe comes with 80 lb or 90 lb injectors i think.