5.0 cobra motor, build for Camaro-Mustang-Challenge

doc stang · Jul 27, 2009

help me figure out what to do.

i have a 95 mustang gt, with an untouched '95 5.0 cobra motor in it.
it is currently putting out 225 rwhp/275 rwtq,
currently with an aluminum drive-shaft, H pipe, no cats, stock exhaust manifolds, and AC delete.
it is currently legal, though underpowered, (for weight), for the Camaro-Mustang-Challenge spec NASA road-racing series.

i would like to see 265 rwhp, 315 rwtq, which would get me to a great point for running in the hotter CMC-2 division.

in CMC-1, essentially no engine mods area allowed,
in CMC-2, i could switch out to gt40p heads, and a ford racing e303 cam.

these would seemingly be good moves over a stock 5.0, but since this is already a "cobra" 5.0 motor, would these changes be a step forward or backwards?

for anyone REALLY interested in figuring out what i should/could do . . .
here is the link to the rules pdf:
http://www.camaromustangchallenge.com/docs/CMCRules2009.pdf

Chythar · Jul 27, 2009

Do you have a Cobra J4J1 computer in this GT? If not, you have left a lot of power on the table - the GT computer doesn't have a decent tune for the extra power the Cobra engine puts out. You can get a chip to update the GT computer's program to the Cobra's, if you wish.

doc stang · Jul 27, 2009

what to look for

would teh entire ECM unit be changed?
is there some identifying mark on the ECU/computer?
or is it just a chip tune?

based on those numbers, for an otherwise untouched 95 cobra motor, would you think it has been upgraded or not?

Chythar · Jul 27, 2009

The Cobra was underrated at 240HP stock, I believe it usually came in around 260-270. The ECM does not have to be changed if you get a chip. Each Mustang computer has a code on it; 94-95 computers have a 4-digit code on a sticker right near the harness connector. The Cobra's code is J4J1.

Based on your numbers, I think you're running a GT computer. You can If you're willing to do it yourself, you can buy a chip and a USB burn unit from Moates.net, and burn the J4J1 program on to the chip. When the chip is plugged in, your computer will basically be a Cobra ECM. On top of that, you can do your own tuning if you choose to do so.

urban96 · Jul 27, 2009

i believe out of the box the gt40p's flow more... but since you want to stay in that class you can either pick up an extra set of gt40 or gt40p heads and have them worked over (ported. polished. milled, good valve job, good springs) it should net you easily between 260-290rwhp depending on the cam and other mods.

Also get that cobra lower intake ported and port matched to the heads.

doc stang · Jul 27, 2009

difference between gt40 and gt40p's?

pretty strict rules, to keep it a spec class, if it aint mentioned, it aint allowed.
p/p aint,

for example:
(from the rulebook)
3.11 Tolerances
Unless otherwise specified, all published measurements infer a tolerance of + / - one-half of the last
specified decimal place. All rounding will be done to the nearest decimal place that is specified in these rules. In a case where a measurement falls exactly on the halfway mark it shall be rounded up or down in favor of the competitor.
3.11.1 Fuel Pressure Tolerance shall be +/- 2psi for EFI cars and +/- 1⁄2 psi for carbureted cars.
3.11.2 Timing tolerance shall be +/- 1 degree.

7.14 Engine Balancing / Rebuilding
Engine balancing is allowed. Lightening of parts beyond the minimum required to balance is prohibited.
Boring/honing is allowed up to 0.060 over. Head/block milling is allowed but only as far as required to square/clean the surface area. Compression ratio shall be no higher than 10.0 to 1 for iron head engines and 11.0 to 1 for aluminum head engines.

i hope that it is on just a gt tune
and i believe that upgrading teh ecu/program would be allowed within the model yr.

if the code on the box does not reflect it to be j4j1 computer, . . .
what would be the easiest/cheapest way to figure out if it has been chipped?

i am sure i cant have a specific custom tune, but i imagine upgrading to a cobra ECU (or at least COBRA tune) would be allowed,

the car is gonna have cobra engine, brakes, hood, bumper cover, and wing by the end of it all,
so the tune will essentially make it just another cobra clone, and still be series legal,
i hope

nmcgrawj · Jul 28, 2009

Dont forget the cobras were calibrated for 24lb injectors....using the same GT MAF. Using 19lb injectors with a cobra computer will leave u lean. Maybe a bump in fuel pressure could make up for it, or perhaps u wont be too lean....

Anyhow, are u only allowed to run "ford" stuff? My gt40p, explorer intake with a turbo cam ran pretty damn hard. Never went to the track or on a dyno but it was quick.

Chythar · Jul 28, 2009

doc stang said:
if the code on the box does not reflect it to be j4j1 computer, . . .
what would be the easiest/cheapest way to figure out if it has been chipped?

i am sure i cant have a specific custom tune, but i imagine upgrading to a cobra ECU (or at least COBRA tune) would be allowed,

the car is gonna have cobra engine, brakes, hood, bumper cover, and wing by the end of it all,
so the tune will essentially make it just another cobra clone, and still be series legal,
i hope

The chip plugs into the diagnostic port at the top of the computer, you can't miss it. If you have a metal plate on the top that's flush with the rest of the metal housing, you don't have a chip.

urban96 · Jul 28, 2009

what color are your injectors? blue or orange?

if their blue and the car is running good you probably have the cobra computer (24lb injectors)
orange---gt

Dino Dino Bambino · Jul 28, 2009

Chythar said:
The Cobra was underrated at 240HP stock.

But not by much. Stock Cobras put down an average of 215rwhp/265rwtq which translates into about 250hp/305lbft at the crank.

revhead347 · Jul 28, 2009

The rules basically say you can't do anything to the engine. Plus, you take a weight penalty for extra power. I think that engine makes good power the way it is. I wouldn't mess with it, unless you want to cheat.

Kurt

doc stang · Jul 28, 2009

revhead347 said:
The rules basically say you can't do anything to the engine. Plus, you take a weight penalty for extra power. I think that engine makes good power the way it is.

i don't know a whole lot about 5.0's, and little enough about s-197s, which is where my limited mustang/motorsports education/indoctrination started.

i bought the car in its current condition, and its prior owner ALSO bought it as is, and really just drove it for a while as he progressed through the Hight Performance Drivers Education series, on his way to his competition license. He did nothing to modify or improve on it (not that that was wrong), outside of basic maintainence (brakes, and fluids).
there have been a few things i have asked him about it, which he hasn't been able to answer. i want to know more about it, to be sure nothing is being left on the table.
ironically, as i was reading through a boatload of old posts and threads on the camaro-mustang-challenge forums, i cam across a post of his, lamenting its power output compaerd to other cobra motors. (maybe i wish i had see that post before i bought the car ???

revhead347 said:
I wouldn't mess with it, unless you want to cheat.
Kurt

in no way, do i want to that,

i just want to make sure it is doing what it should be. it sounds like it is actually on par with what most CMC'ers are getting out of their COBRA mills, there seem to be a few outliers, in texas, and calif., who are seeing closer to 260/300 at the axle.

final5-0 · Jul 28, 2009

I quickly skimmed over the thread and gotta go in a sec

Couple of things

You would not be setup correctly with the GT pcm and using all the
Cobra hardware

What would be going on is the pcm thinks it is using 19's when in
truth 24's are in place so each pulsewidth is gonna squirt more
juice

The diff between regular 40's and the 40p's ain't enough to be
all that concerned with IMHO

Grady

Daves94vert · Jul 28, 2009

Is an upgrade to a 98 cobra feasable? Sell the 5.0 cobra for a 4.6 cobra.

Daves94vert · Jul 28, 2009

Don't forget a canton oil pan.

revhead347 · Jul 28, 2009

Yeah, if it has 24lb injectors (blue ones), then the computer it is probably fine. If it had a GT computer and big injectors, then it would be running butt rich. Sounds like that engine is making good power. I would run it one season just the way it is, and after you get some seat time, then mess with it.

Kurt

Daves94vert · Jul 28, 2009

Have you raced b4? Maybe try getting some seat time in some scca solo autocrossing.

doc stang · Jul 28, 2009

updates, thanks for the help and advice

Daves94vert said:
Is an upgrade to a 98 cobra feasable? Sell the 5.0 cobra for a 4.6 cobra.

no, i bought this as a ready package, it is already CMC-1 legal, gutted, caged, and ready. i bought this to use for "driver modifications" while searching for an s-197 to build up.

Daves94vert said:
Have you raced b4? Maybe try getting some seat time in some scca solo autocrossing.

not racing yet,
i have about 24 track days under my belt and am currnelty an HPDE 3
anticipate getting my time trial license in 2 weeks at road atlanta.
and could probably sit for NASA competition school whenever i want at this point.

revhead347 said:
Yeah, if it has 24lb injectors (blue ones), then the computer it is probably fine. If it had a GT computer and big injectors, then it would be running butt rich. Sounds like that engine is making good power. I would run it one season just the way it is, and after you get some seat time, then mess with it.

Kurt

yup, blue injectors, (thanks for the lesson)
power seems on par wiht most of the rest of the cobra 5.0s across the nation.
bought it in feb., 1/2 season of DE under my belt in it

hope to be racing wheel to wheel by the fall, and ready to really fly in 2010
they are combining CMC-1 and CMC-2 for 2010, so i need to find some more power/torque; and also shed a little more weight somehow.

urban96 said:
what color are your injectors? blue or orange?

if their blue and the car is running good you probably have the cobra computer (24lb injectors)
orange---gt

blue
thanks for the lesson (no sarcasm)

Chythar said:
The Cobra was underrated at 240HP stock, I believe it usually came in around 260-270. The ECM does not have to be changed if you get a chip. Each Mustang computer has a code on it; 94-95 computers have a 4-digit code on a sticker right near the harness connector. The Cobra's code is J4J1.

Based on your numbers, I think you're running a GT computer. You can If you're willing to do it yourself, you can buy a chip and a USB burn unit from Moates.net, and burn the J4J1 program on to the chip. When the chip is plugged in, your computer will basically be a Cobra ECM. On top of that, you can do your own tuning if you choose to do so.

it IS a J4J1 computer.
thanks,
this and the color on the injector is just the "fund-of-knowledge" stuff for which i am looking.

question now is:
would an E303 cam help or hurt,
not looking for area peak numbers, but area under the curve across the rpm band.

they may allow shorty headers for 2010, to help the CMC-1 guys catch up to CMC-2 levels.

final5-0 · Jul 28, 2009

My thoughts on possibilities would be

Cam

I've never claimed to be all that cam savy ... but

If you can use the e-cam I would get with someone who knows about
cam events and see what could be done with different rocker ratios
and moving the cam up or back a bit

Tune

I have no doubt I could find some power there

Now ... it is not like it would be a T O N of power
but
I'd say 5 to 15 is a range that would be reasonable

Grady

5.0 cobra motor, build for Camaro-Mustang-Challenge

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