TBIWorks

iTrader: (2)

Does anyone know what pound injectors come in the holley TBI(for 5.7L)? Also, I read that someone was having trouble with the stock fuel fittings matching up to that throttle body. I thought this unit was supposed to be a direct bolt on replacement. Another question, can you use this unit with the stock intake, or does it require the holley pn# 300-66? Thanks fellow TBI guys, I am building this car and I need to get my ducks ina row before I order everything.

JPrevost

I didn't have any problems with mine. Brian Felts says his don't work but they should. The only reason it wouldn't work is if it's from a projection system which uses barb fittings for rubber lines.
The injectors on the 5.7 version are #65 and make sure you make the fuel pressure regulator adjustable before installing on the car. If you need a tech article to do it check out my website.

TBIWorks

iTrader: (2)

HEY, I thought that the one on the holley was already adjustable. if it isn't, then instead of modifying it, I may just buy the turbocity.com one instead. also, on a 330hp 5.7, how much fuel pressure w/ NOS, and w/out?

fast_broker

iTrader: (1)

65pph injectors are NOT enough to support 330hp unless you go up about 60% on the fuel pressure. That is pushing both the pressure limit AND the duty cycle limit of the Holley Injectors.

If the unit really comes with 65pph'ers (I thought they had 85pph'ers), trade the 65's in for some 85pph'ers if they are new THROUGH HOLLEY DIRECTLY. They will do it and are pretty nice about it but don't run the vehicle first (ie, don't use the injectors) to make it easier.

Brian Felts

Well the only thing that will not work is the fuel Fitting on the back of the tbi. The stock fuel lines will not bolt up.


Brian

JPrevost

My unit bolted right up to the stock fuel lines. I just had to move the adaptors from the old unit to the holley. They unscrew from the injector pod so it wasn't a hard job.
As for the Holley using 85 injectors on the 5.7L 2" 670cfm unit doesn't make sence. FB, if they used 85 injectors and guys bought the 2" unit and bolted it onto their mild Lo5 pickup 350 then it would run SO SO SO rich. Stock injectors on 5.7L is between 55 and 65. Anyways, I'm running the holley injectors (pretty sure it's 65 from all my sources) and I ran a 102mph which is about 300hp. That was with the fuel pressure cranked a bit but unknown fuel pressure. I'm going to increase the fuel pressure a little more now that I'm using your timing tables. Thanks again for those tables, much better than stock. I'm sure with a little more fuel up top I'll run a 104mph or more which is ~330hp.

fast_broker

iTrader: (1)

Dyno test and I will believe. I also thought (Holley) they offered smaller injectors for 305 use if the supplied 85pph injectors were too big. Free swap. learned on this board year ago or so, I think???

Chassis and engine dyno tests don't lie. Spend the 50-65 bucks for 3 chassis dyno pulls. Worth the money.