347 Motor tuning

[mbuono]

Had my 347 with Kenne Bell 2200 on dyno and only made 463 HP and 478 torque. Air fuel ratio was up and down between 14 to 10 right at 4200 then to 12 at 5800. Ordered FordChip to hopefully correct some of this but not sure where to go from their.

Mike

[Greg@SVTOA]

I have my 347 running pretty good with no power adder and small valve heads. I run the stock intake and small shorty headers. Car makes tons of low end torque and it a lot of fun to drive.

What are the other details of your combo? What heads do you run? What cam? Gearing? What size fuel injectors? What style of fuel pump(s)? When I ran a blower (it was a V-1) I ran a 190LPH in-tank and a T-rex inline pump.
What style of intake tubing do you run, and how much boost?
Rather then a chip, have you thought about the EFI Extender? You can find them on the web for sale cheap and they really do work well...
What size and style of MAF do you use?

More info please?

[mbuono]

It has ported Edelbrock heads, 36# injectors 190 fuel pump with T-Rex, Crower cam, 80 Univer 75 TB, PIH 89 A9L, MSD boost retard, with 355 gears when through 1/4 at 5500 on 10.5 x 26 x 15 ET streets at 125.9 mph.
Mike

[Greg@SVTOA]

If your trap speeds are 125 MPH, you are making in excess of 540 horsepower. Something's not right here, or perhaps you have made a change to your combo in between the time since you trapped 125 MPH and dynoed at 463. Using 3550 lbs as a constant (for comparison) and 463 HP, that calculates to 118 MPH trap speed. Using the same weight and 541 HP, you come out right at 125 MPH. Which means that you either made a change to the combo and regressed, or there is some missing element here that is not apparent in your post info.

If you are trapping at 125 MPH with the combo you have and are not blowing head gaskets, things are working fine. If your car weighs more then 3550 lbs, and your trap speeds are in the 125 MPH range then you could be making upwards of 565 HP

[mbuono]

Well 560 sounds about right for the motor and at rear wheels should be 480 range. A friend has modified ZR-1 vette making 485 at rear wheels and trap speed was 122 the same night and weighs 3500. The dyno was a dyno jet, then a week later was at a dyno challange on a Mustang dyno and it made 450. No changes were made between track and two dynos, even my Tazzo is reading between 444 and 452 hp.
Got chip yesterday and plan on going to dyno Tuesday and track Friday next week to see if it helped my a/f ratio.

Mike

[Greg@SVTOA]

Hopefully the chip will solve your problem. If it matters any, for the sake of discussion- I notice you have the PIH/A9L setup, and now a chip. The EFI Extender would take the place of the PIH setup, which would cure all that ails the 94-95 computer, (like the concept of the PIH/A9L) plus it would allow flexibility in tuning that A/F ratio for you. Think about it this way: If you re-dyno the car, and then find the A/F ratio is still not where you want it, unless the place where you make your dyno runs has the chipmaster program or whatever program is used to flash that chip, you will now have to have another chip burned, at additional expense and time. Contrast that with the EFI Extender- You dyno the car, check the A/F ratio, and a simple twist of a screwdriver allows adjustments to the A/F ratio. These adjustments are also "permanent" as far as the EEC goes. It's a popular tuning "trick" to adjust the fuel pressure in an attempt to change the A/F ratio, but the problem there is that the computer will sense this change in time and simply adjust the injector pulse width to bring the A/F ratio back into the paramaters dictated by the preprogrammed tables. With the EFI Extender, this is never an issue.


Adjusting the Extender is as easy as twisting a screwdriver


Chip burning can be hit or miss at best, and the best way to go the chip route is to have the car tuned by a company that has the chip software AND a dyno, so the adjustments and tweaking are done on the spot and the best chip for your combo can be determined with the car on the dyno, before it leaves the shop.

Hope this helps...

Greg

[mbuono]

That sounds like something to look into. Can you adjust the a/f throughout the rpm band or is it one ajustment for the entire band. Thanks for the input.

Mike

[Greg@SVTOA]

You make the adjustment to the A/F period. It encompasses the entire RPM range.

Greg