80 Hp increase minimum
 

When I purchased my car the engine had 1500 miles on it. A 5.0 stroked to 347 cid. Edelbrock performer heads, aggressive hydraulic roller cam. Mass Flow EFI system. The previous owner said the builder estimated 400 hp. Putting all the engine specs into my "virtual engine dyno pro" and "dyno2000," both software packages estimate 400 to 450 Hp at the flywheel.

My first impression, when I drove it, was that it was putting out about 300 hp maximum. The engine light was coming on. By the smell of the exhaust and the black sooty side pipes, I new it was running way too rich - which we all know will kill Hp. Well the seat of my pants is not an accurate dyno, but with 3.50:1 rear gears, you could stomp it at any rpm in 1st gear, and it could not break the tires loose (P295 50R 15 BFG T/A).

I've been working my way through the EFI system. The engine light code was caused by the right O2 sensor plug being loose. That helped a little. The fuel pressure was 43 psi and should have been 40. Correcting that made some improvement. Today I cleaned the mass flow meter - it's a hot wire type, and wow! What a kick in the pants. I was not expecting the tires to light up just stepping on the throttle at 1500 rpm (the cam lopes until 2000 rpm)

I figure a 240 lb passenger is like a 40 Hp reduction. The power increase is like taking two passenger out of the car, hence my 80 Hp increase. Sorry if I bored anyone to death, but it was exciting to me.

347
 

OLDDOG
I have a 354/5.0 that I build last winter. It has 89 Ford EFI system with aluminum head and all the go fast parts. I had it dyno'ed and a custom chip burned for this engine and I think it makes all the different in the world. I had a 5.0 with a lot of speed parts but never got it to run the way I though it could. So last winter I bought a stroker kit and build the new motor. I had plans on using most of the old parts but I did buy new heads, cam, rockers and injectors. I think if I had a custom chip for the old motor I would not have build this motor. Look at getting a chip. You have to have good parts (new or like new) to make it run like it should but the custom chip brings all the parts together for optimum performance.

Dwight

Dwight

I have been talking to Mass Flow technical support. I have been talking to them about adding a custom tune chip to my computer. They say that the modifications to my engine are too far from stock and that a custom tune would make more hp.

I have been very happy with the help I have been getting, and I do think they know their system. However to do the custom tune all they need to know about the engine is the displacement. Heads and cam didn't seem to be important to them (although I had already told him that). That kind of goes with their claim to fame, as they claim that all you need to know is the mass of the air flowing into the engine to add the correct amount of fuel. They basically claim there is nothing to tune. However I do not 100% buy this. Especially since the timing is also controlled by the computer.

The best (easiest) way to tune your car to its best potential is to take to a dyno shop and have it chassis tuned. Numbers don't lie.

olddog, good stuff, I enjoyed that. Amazing how sensitive FI is. Another thing I learned when I had my Excalibur was how important the throttle position sensor is!

Dyno
 

I send all my specs to Dyno Speed Racing in Memphis, Tn and Joe burned a chip for me. The motor ran lean when we chranked it the first time. I had to trailer the Cobra to Memphis and get it dyno'ed and the chip tuned.
Timing and fuel pressure are set at stock settings. The chip control idle, fuel pressure, increase / decrease in timing and more. I have a 24 lb mass air and 36 lb injectors. The chip corrects for the differents. Nice.

Dwight

Tuning that FI stuff is almost an artform if you are outside the manufacturers application.

Good post.

:D