Non Mass Air Mods?

[jpchefz]

I have an '88 GT without Mass Air. Was thinking of adding a Cobra intake and 65MM Throttle Body, 24# injectors and new heads. My question is this. I have heard that you can only go so far modding a Non Mass Air car, before you start having driveability issues. Is this true? Any tricks to modding a car without mass air?

 

[f8tlfiveo]

Most of the time if you don't touch the cam you will be ok

 

[NIKwoaC]

Can't (or at least, shouldn't) change injectors without a tune.

Speed density relies heavily on manifold vacuum during idle and part-throttle conditions. Camshafts that reduce manifold vacuum (pretty much any aftermarket cam to some extent) will "confuse" a speed density computer, causing drivability issues. Milder cams have less of an effect on this than "bigger" cams do (longer duration, longer overlap).

You can get away with speed density to an extent, more if you're willing to raise the fuel pressure once the 19lb/hr injectors reach their limits on stock fuel pressure.

My car is still speed density, and I have a (very lightly ported) GT40 intake, 70mm TB, CAI, full exhaust, etc. Runs fine.

 

[Kdubslugga]

Yeah no need to change injectors yet. Cobra intake is a good choice. I made 495 rwhp with one, so you have some room to grow with it. As long as you dont do heads or cam you should be fine. Some things to consider, like you said Throttle body, Electric fan, bump the timing, pullies, headers, hpipe, flowmasters, cold air intake. Along with the intake those upgrades would be ehhh maybe 40 more HP give or take depending on what you have already done!

 

[jpchefz]

Thanks for the info. I appreciate the input.

 

[brands5.0]

Its all in the tune most of the big EFI systems are non mass air F.S.A.T BIG STUFF 3. A good tuner should be able to tune the car for any planed mods.

 

[phutch11]

There's a member of this board, TMoss, that made something like 277rwhp with a non-tuned SD system.

IIRC his combo was some ported GT40p heads, stock cam adv 4 degrees, 65mm throttle body, and a ported corba intake. I'd guess he probably had some decent headers, exhaust, e-fan, pulleys, and other supporting mods as well.

277rwhp is no joke on stock Ford parts. Lots of guys struggle to get that high on a MAF system with similar (or better) parts.

Just a thought...

Good luck...

 

[Mustang5L5]

I have the same mods on my 88. Runs fine. Keep the stock 19# injectors and don't touch the cam. Car will run fine.

Some guys claim sd can't handle bolt ons like that, but i can show you my 88 idling smoothly with intake and exhaust mods....pretty much everything but cam and injectors

 

[NIKwoaC]

This thread got me thinking.

If you put an adjustable fuel pressure regulator on the car and knock the fuel pressure up to 60psi, the stock injectors could support 350 hp at the flywheel (theoretically). That's based on this injector calculator and using .45 BSFC and 85% injector duty cycle. Also assuming your fuel pump is up to snuff. Also don't know how part throttle A/F would look, this is only concerning WOT.

So I'm thinking... Big intake, big heads, mild cam, supporting mods, and stock SD system with 19 lb injectors. 310ish rwhp?

 

[Mustang5L5]

At that point why not convert to MA? It's only maybe $200 in parts.

 

[NIKwoaC]

At that point why not convert to MA? It's only maybe $200 in parts.

More or less, just so you could say "I made 300 to the tire on 19lb injectors and speed density" haha.