Contour Enthusiasts Group Archives Forums Modifications General Mods Changing/ upgrading injectors

I'm thinking about upgrading to 19lb/hr injectors. I read Terry's 'how-to' for injector sizes but had problems with a few of the numbers, as I have no dyno data or compression #'s.
Anyway, how hard is it to change them out? Will the stock computer restrict the 19lb injectors? or will I actually see some gains.
I need to change the injectors anyway, but I'd like to upgrade.
Any info. or suggestions is greatly appreciated!
Thanks,
Rob

Don't know how hard it is to change injectors (but am very interested in the answer). However, your computer will still think it has the old size injectors. You will require some sort of air/fuel control, such as Apex-i S-AFC, or a new Mass Air Flow with optimizer.

Changing injectors should only be about an hour job maybe 2 if it is your first time removing the upper intake. You just need to remove the upper intake, fuel rail, and injector harness.

That's what I figured, seeing as yesterday my buddy and I upgraded his injectors in his Trans-Am. It was pretty simple, but at times tricky with our 'ghetto-tools' :rolleyes: .

PA 3L SVT- I'm looking into buying a new MAF (from ProFlow I believe) with a massive filter anyway. How much more is an optimizer?
Also, is the optimizer adjustable? ie. can I change A/F ratio myself with the simple turn of a knob or is it electrical stuff?
Once again, any insight is greatly appreciated!

Like $150 for the ProFlow one.

It lets you change injector size (between 4 preset sizes IIRC) and has 2 A/F adjustment pots (high & low rpm range Only! not specific or detailed)
Very basic, but can definitely help out...

The Apex-i is ~$329. Can set A/F at low and high throttle. A/F is set in 1000 RPM increments and interpolates between set points. High throttle should be tuned on a dyno, but you can (if you are careful) set the low throttle yourself. Do a search and you'll find a webpage by a guy with a DSM that gives a good how-to on setting yourself. Also gives a unit that can display info (RPM, A/F from O2's, etc). Better control than a MAF optimizer, but it costs you.

Unless you have done a lot of modifications, the 19# injectors will be of no benefit. A lot of work and expense with no improvement in performance. It is not an upgrade unless you need it. If you don't need it, it is a downgrade.

So unless you enjoy beating yourself up, don't do it until you have made extensive modifications. Things like hotter cams, ported heads, 3.0 conversion, much bigger intake and exhaust, headers, etc. And not just one or two of them, several of them.

I need to replace them anyway, so I figured why not upgrade to SVT spec. injectors while I'm at it. Plus, I can get the injectors incredibly cheap through a friend (my friend with the TA mentioned above got 8 24lb/hr injectors for $100 Canadian- apprx. $60 US!).

I too have been looking in to this upgrade as I WILL need the extra fuel at WOT. Our fuel systems (95-97) utilize side feed injectors and to date I have been unable to source another Ford application with 19# side feed injectors. When/if you find them please let me know the p/n and/or application they come from.

I'll let you know.