24# Injector ??

[ZEN50]

Trying to figure out if 24# injectors are too much for my set up? Current set up is ..........
GT40 heads with upgraded valve springs
1.6 Roller rockers
E303 cam
Cobra intake
65 mm TB
Motorsport headers
24# injectors with matching mass air meter

I've put around 125 miles of around town driving on it so far and just put 11.4 gallons in it on recent fill up. So that equals roughly 11 MPG.
Am I burning too much fuel?
Was planning on taking this car to Mustang Week in Sept. on a 1000 + drive, not so sure I want to do that currently with the crappy gas mileage?
Should I go back to 19# injectors and the stock mass air meter?

[homer302]

19lb injectors would pretty much be maxed out with that combination but they could POSSIBLY work. You essentially have a Cobra engine now which did use 24lb injectors. You would have to have a proper dyno tune or at LEAST get a AFR gauge to see where your fuel ratios are at to really know what is going on. And of course, mileage all depends on how you treat the car too. 11 MPG sounds pretty bad though.

[Ourobos]

^ Agreed.. 300hp at the crank is about the limits of 19#..

That being said, I've ran that similar combo multiple times, and I always stay with 19#. Never any issues

[erratic50]

With 19's you can always add an adjustable fuel pressure regulator or pull out some timing advance if you are lean.

Personally Id go to the mcparts store and get a 93 Cobra ECU. I'd also get a stock cobra calibration 70 MM MAF.

93 Cobras often got better MPG than GTs on the interstate because of their 0.63:1 OD and revised torque curve.

it sounds like your motor is somewhere near pig rich. Are you certain you have 24's?

[ZEN50]

Pretty darn sure they are 24#, came with the crate motor but am not sure on how to verify that? Doesn't smell rich? The MAF is 75mm.

I haven't beat on the car/engine since the crate motor swap, just normal driving for now. Am running 3.55 gears, was before also.

Any part #'s for a Cobra ECU, MAF ???

[Ourobos]

If a Ford injector, blue is 24#, where orange is 19#. What meter exactly, it should be calibrated to your injectors - you said matching so I assume it is.

[ZEN50]

Yes, calibrated for the 24#, Pro M maybe? Don't have the car here at the moment, getting mufflers installed. Will take a look later today at injector color, don't remember them being blue? Might be aftermarket?

[Ourobos]

They should have a part number on them either way, not sure how easy it will be to see though with them installed. Pro-M is a good meter IMHO.

[Broncojunkie]

I have a similar setup in my 88gt. I went with 24# injectors and pro m maf. It has a b303 with 1.7 rockers, explorer intake, worked iron heads from a 69 302, iirc (closed chamber heads with bigger valves and port work). I just went from 3.55 to 3.73 gear. I definitely noticed a big drop in mpg from the stock setup, but then again, I tend to get into it a lot more lol. Anyway, it seems to run fine for the most part. I need to mess with the timing a little, i believe. It wants to lug a little at low rpm. But the plugs don't show rich or lean condition at all. Fuel mix seems to be about right, just judging by plugs and exhaust smell, performance, etc.

[erratic50]

You leave a crap load of power on the table with a "recalibrated" (should call it what it is -- broken) MAF and an ECU tuned for 19's. It causes removal of a lot of timing advance.

Care is required so you don't go lean if you have a larger MAF. Makes sense right? Here's more info. http://www.veryuseful.com/mustang/te...ck-gt-maf.html

i suggested a 70MM Cobra MAF because it's big enough for your application and it's what the cobra ECU is tuned to work with. ECU part number and tune info is published here: http://www.1993cobra.com/data.htm

any Mcparts store will have a reman ECU available for a 1993 Cobra. It works with 24's and a STOCK calibration MAF. Not tuned. The ECU knows it has 24's so you get there the right way.

Lumpy cams do yield reduced mpg. Get an A/F wideband. After all the money on a crate, have it tuned or DIY with binary editor and a moats quarterhorse....

good luck - best regards!

[Broncojunkie]

Are the cobra ecu's readily available? Haven't checked personally, but I know none of them had a9p/a9l units. I'd be really surprised if the cobra ecu's were plentiful.

[erratic50]

3 months ago my friend went to his autozone and asked for one then walked out with it. And it wasn't stupid expensive either.

[ZEN50]

Do you know if your friend had to pay the core charge?

[Broncojunkie]

When I was looking for an a9p/l a couple years ago, none of the stores had any of them. Couldn't even get them. If I had it to do over again, I would have spent a little extra and gone worth a stand-alone system.

[Broncojunkie]

When I was looking for an a9p/l a couple years ago, none of the stores had any of them. Couldn't even get them. If I had it to do over again, I would have spent a little extra and gone worth a stand-alone system.

[ZephyrEFI]

Following this since I have a similar setup, just with an HO cam (looking to upgrade). And I DO think mine's getting terrible mileage too, even with the small amount of driving I've done. And my exhaust smell indicates a rich condition. I plan on doing some sort of tune at some point, but I'm interested what direction you go. Good luck!

[erratic50]

Looks like I'd have to order it buts it's available.

[erratic50]

There is a second product available for $207 plus $41 core also. 78-4352

I have a moats quarterhorse. I'm going to do the moats plus my A9L and Binary Editor and BE logging software on mine when I get that far. Wideband O2 of course. Going to 47lb EV6 injectors and an E85 tune once I'm done playing with stuff. Fresh 90 short-block, Comp cam, Edelbrock heads, Typhoon EFI, etc.

[ZEN50]

Any idea on the difference between the F3ZF-CA and the DA computers? And why a $50 difference???
Confused.......

[Broncojunkie]

Looks like I'd have to order it buts it's available.

I went through this before. Looks like it's available but tried to order and I got an error of some sort. Called the store and they couldn't even order it.

[erratic50]

Looks like DA is a "universal" 89-93 Stangs while CA is Cobra.

Cobra ECU needs the 70MM cobra MAF for correct operation BTW. Tom moss graphed out the differences on his site. you end up a little rich up top with a regular old MAF.

Not sure what the order situation is. My friend just walked in and bought one. Lucky?