Mustang GT Newbie question

jdevarie · 11-13-2003

Hello all, I just purchased a '88 GT that had some mods already made. These are as follows per the previous owner:

.030" over bored shortblock (he mentioned GT40 block??)
Cobra intake(both) with bigger injectors?
Double exhaust (w/o cats)
Slightly radical cam (rumbles a lot)
He mentioned that the engine had been built to be used with a mass air flow sensor.
It is my understanding that this year stangs use some other method, what is it? He said that the injectors that the car has installed are the correct size for the mass air flow sensor set up. He gave me a cobra computer that he said I should use when the mod is implemented.
I just drove the car about 20 miles home and I loved the drive. Once in my garage I could tell that the car seems to be running rich (has a heavy gas smell). I also noted during the drive that if I eased out on the gas pedal, I would get some hesitation of the car accompanied by some noise coming from like the rear end. The same happens at low speeds much like when the car is being driven in a gear higher than required.
I welcome any comments or advice. The car needs work it is a convertivle that sounds and shakes the way I like.

Thanks in advance.

glenn · 11-13-2003

I don't know if he was blowing smoke up your ass to sell you the car, but you do not need bigger injectors for Mass air, the stock size are 19lb injectors, you car is called speed density. The reason it might be smelling rich is if it does have bigger injectors like say 24's, your car is looking for the stock 19lb injectors. As for the GT40 block, you most likely have a standard 302 bored out to a 306. Best thing to do is a good tune up, check if you do have 24's and throw some 19lb injectors back in.

jdevarie · 11-13-2003

Thanks for the message. 24 sounds like the number he mentioned I also have the stock intake manifolds with the injectors still on. Wouldn't it be better to go with the mass air system than to stay with the speed density one? As I understand it, mass air works better with mods such as camshaft etc.

Thanks in advance.

Jimmy

GhostDog 5.0 · 11-13-2003

That rich smel can come from lack of cats.

tmoss · 11-13-2003

The guy who sold it to you told you hed did the conversion and matched the MAF to the injectors right?

Heads up - that Cobra computer is used with a 19# MAF sensor. The Cobra computer converts the 19# MAF signal to the proper injector pulse width for 24# injectors. This is a one and only odd situation with Ford EEC and MAFs. If he used a 24# MAF, then the EEC will more than likely try to run the car rich, but the EEC has the ability to adjust fuel trim by sensing the O2 sensors and adjusting fuel curves back into range. The limit of that adjustment is about 25% however.

glenn · 11-13-2003

Quote:

Originally posted by jdevarie
Thanks for the message. 24 sounds like the number he mentioned I also have the stock intake manifolds with the injectors still on. Wouldn't it be better to go with the mass air system than to stay with the speed density one? As I understand it, mass air works better with mods such as camshaft etc.

Thanks in advance.

Jimmy

Some guys will say stay speed density, and most guys will say convert. I've seen both, and was happy with the conversion. I know that speed density cars don't like a lot of camshafts. If you do the conversion, you will need a MAF that is calibrated for 24's, or like TMOSS says use the cobra computer.

Quote:

Originally posted by tmoss
The guy who sold it to you told you hed did the conversion and matched the MAF to the injectors right?

Heads up - that Cobra computer is used with a 19# MAF sensor. The Cobra computer converts the 19# MAF signal to the proper injector pulse width for 24# injectors. This is a one and only odd situation with Ford EEC and MAFs. If he used a 24# MAF, then the EEC will more than likely try to run the car rich, but the EEC has the ability to adjust fuel trim by sensing the O2 sensors and adjusting fuel curves back into range. The limit of that adjustment is about 25% however.

the car is speed density still.

jdevarie · 11-14-2003

Thanks a lot for the replies. I do have the cobra computer that I will have to install once I get the MAF and the related accessories. Hopefully that will not be too dificult.
I will be installing cats soon so that I can register the car, here in massachusetts, you need them for real.
Any ideas where to get the MAF sensor and related accessories?

Thanks in advance.

Jimmy

glenn · 11-14-2003

www.corral.net check their classified section for a used cobra MAF, or even the whole conversion kit.

Adam94GT · 11-14-2003

A GT40 block is nothing special. It was most likely the GT40 longblock that Ford Racing Performance Parts manufactures. There's nothing special about the block itself, it just has FRPP Gt-40 heads and an e303 or b303 cam.

jdevarie · 11-14-2003

Thanks again for all replies.
Glenn, thanks for the link, a ton of stuff for sale there.
So Tmoss, according to what you are saying, I should get the stock MAF which is made to work with 19# injectors. Correct?

Thanks in advance.

tmoss · 11-15-2003

Yes, the stock EEC and the Cobra EEC are made to use the 19# calibrated MAF. THe Cobra computer does the correction to control 24# injectors.

jdevarie · 12-03-2003

Well, I finished the conversion and was also able to install the complete stock cat exhaust. The car does not make that nice sound anymore but at least was able to pass Massachusetts new strict emissions test during the inspection. That was a relief, now the question for me is: Should I put back the H pipe? I have good flowmasters installed and they sound great.

Thanks a lot for the replies to my posts.

regards,

Jimmy

glenn · 12-03-2003

I say throw it back on. How does the car feel? Any differance? Anyway, good luck with the rest of your future mods.

jdevarie · 12-04-2003

The car still feels powerful (gotta love that pull at WOT in first and second gears just before redline!) but the sound is kinda disappointing. This is my first stang and believe, I have missed a lot. This is awesome.

Thanks

jd