I need help choosing fuel injectors for my 1993 T/A (A4). I am having a whole host of mods done as we speak but everything about fuel injectors confuses me so I need help. The mods that are currently being done are as follows:

NEW Stock LT1 motor
LE2 Heads
Custom billet cam: 228/236 .592.592 110 LSA
Comp 4502-16 studs
Comp 1618-16 rockers
Comp Cams 1-pc chromoly pushrods
Cloyes Double Roller TC
Meziere EWP
3" LPP LT headers & Y-pipe
Magnaflow Hi-flow cat
Magnaflow Cat-back exhaust
Performabuilt Stage 2 tranny
Yank SS 3600RPM Stall converter
Racetronix (Walbro) 255lph FP
Taylor 8mm plug wires
NGK TR55 plugs
UMI double-adjustable rear LCA's
UMI panhard rod

My plans for the car are to have fun driving it N/A for a while, then take the motor that has been removed and prep it for FI about 3 years from now. Trying to do the FP and injectors now, though. So, considering I eventually want to run a single turbo setup (max of 750RWHP), which injectors should I go with? Racetronix sells Siemens injectors that flow at 63# but they're cheaper than the Racetronix 55# ones. Why? here's what I'm looking at.


http://www.thunderracing.com/shop-by...0/details.html

http://www.thunderracing.com/shop-by...6/details.html

I forgot to mention the intake is being ported by Lloyd and I have 3.73 gears goin in as well. And a B&M 24,000 BTU tranny cooler and a new PCM with proper tuning.

 

My app is forced induction (97ss 383-D1 MM6). I run 72# Seimens peak and hold (low impedance) injectors with an Acceleronics driver (Acceleronics.com). He also sells injectors and the complete package. I would also use a WB O2 tool for tuning.
B.

 

Thanks for the response but according to racetronix- "This low-impedance injector is designed to work with peak and hold injector drivers typically found in aftermarket ECM/PCMs as well as dedicated injector driver modules sold by Racetronix" Given all of the mods I've done so far, I'm on a tight budget at this point and don't want to buy anything that isn't absolutely necessary. However, if I go with these low-Z injectors, I shouldn't have to upgrade when I go FI. Is the same true of the High-Z injectors?

 

If you're on a budget now, wait until you have the coin when you do your turbo build. The right injectors will be a drop in the bucket when that time comes.

I'd find some 36# or 42# injectors to hold you over until then.

 

But if I can afford some 63 or 73#'s now (high-Z), its best to do it now, right? I'm kind of worried that the stock injectors and fuel pump will be at their limit given this setup. I'm going from a pretty much stock car to nearly every known engine/exhaust mod. I'm anticipating around 420RWHP with this setup, 400 minimum.

 

There's no way "stock" injectors can handle that setup. But why complicate things with seriously oversized injectors? It's flywheel HP that determines injector size, not rear wheel. If you make 500HP at the flywheel, the minimum recommended injector size would be the 36's. Get a set of 42's and you'll have a bit of head room for HP increasing tweeks, or mineshaft altitude density days.

 

Ok Fred, thank you very much for the explanation.