The previous owner of my 93 cobra installed a 73mm MAF and 70mm throttle body, does anyone know if this increase over the stock size (70mm MAF and 65mm throttle body) cause the car to run sluggish? The timing is set at the factory 10 BTDC.
It can't hurt, and theoretically it should make the car faster. Also, I believe the opening on the upper intake on a Cobra is actually 70mm, so it should match up well. HOWEVER, if the MAF meter is not calibrated right, it can and likely will hurt performance. Double check that the MAF meter is the right one for the ECU and injectors (keep in mind the Cobra uses a different ECU than what the other 5.0's use), bump the timing up to 14-16 degrees advance, and it should run like a raped ape.
Edit: Also, check that the TB opens all the way when you stomp the loud pedal and that the TPS is in range (about .9 volts closed KOEO). If you know what that means, you're in good shape. If not, use the search function to find out how to check throttle position sensor voltage on this site. Good luck!
P.S. THIS IS MY 100TH TECH POST!!! WOO HOO!!! :SNSign:
On the Cobra the ECU is calibrated for the injectors not the MAF. I think you want an aftermarket style '93 Cobra MAF that works for the Cobra, the regular Mustang style mass air (73mm = C&L?) won't work with your car.
On the Cobra the ECU is calibrated for the injectors not the MAF. I think you want an aftermarket style '93 Cobra MAF that works for the Cobra, the regular Mustang style mass air (73mm = C&L?) won't work with your car.
What do you mean by won't work? What would the car run like? The stock MAF was replaced with a 73mm (Vortech) if that means anything. I have the stock MAF should I put it back on?
The ECU is different between the GT-LX 5.0 cars than it is in the Cobra. The Cobra also came with 24 lb/hr (versus the GT-LX 19lb/hr) injectors IIRC and a different (somewhat larger) MAF meter.
THUS a MAF meter designed for a GT-LX V-8 won't operate well with a Cobra ECU and injectors. You can't switch parts around without tuning. Aftermarket MAF meters typically operate by sending a modified voltage signal to the computer to account for different sized injectors.
Honestly, it gets kind of complicated. Put the stock meter on it and see if the car does what you want. If not, its another problem. If it does, then the aftermarket MAF meter you have is junk (or just not Cobra compatible). The TB shouldn't negatively affect performance.
Edit: You asked how the car would run... It would run either rich or lean, depending on the MAF meter calibration. If its too much of either, it will run like poop. If its rich, it'll smoke a lot. If its lean, it'll get really hot and you run the risk of destroying the engine itself.
NikwoaC thanks. I installed the original (stock) MAF and it made all the issues go away. I noticed that the OEM MAF had a baffle where the sensor hangs down where as the after market did not. Now the car responds when I hit the throttle. Thanks again.