Cobra dyno

[Azure]

A buddy of mine just got his car Dynoed last Friday. It's a 2001 Cobra with the following mods.

1) Steeda underdrive pulleys
2) Bassani catted X pipe
3) FRPP FR500 cat back. ( I think thats what Ford Motor calls it)
4) 4.10:1 gears
5) K&N Cold air intake kit.
6) custom burned computer chip.

For all his effort the Dynojet rewarded him with a peak hp number of 292. He didn't send me any torque or rpm reading. I'll try to get them.

He's not to far from the 300 RWHP number.

Steve

[Unit 5302]

Nice, that's right around 350hp at the crank. For some very simple mods, he's got an easy mid 12 car with hook.

[Azure]

He's got the same size tires we do. I don't think he's going to beat the low 13's.

Keep in mind that our track is at 1000' and as slick as a streek of owl crap.

[Julio]

Dont forget the IRS, its not exactly what you want for drag racing...

[04Retro]

That is no where near a mid 12 car...well he may get close with the 4.10 gears if he can get traction but he is going to have to fight wheel hop with the IRS...you also need to take note of the underdrive pulleys...you do not gain HP at the crank with underdrive pullys--you only notice them in the rear wheel numbers as they lessen the parasitic loss from the drivetrain..so instead of a 15-17% loss to the rear wheels you might only suffer a 12-15% loss---so the rear numbers go up but the true horsepower of the engine does not change 1 bit... thus I doubt he is at 350 at the crank (filter, exhaust and chip will not buy him that much--maybe 20hp to about 340)....340 at the crank with a 12-15% loss would net you about 299-289 at the rear wheels--he is not quite there yet....

[Azure]

I thought they fixed the wheel hop problems on the 01 Cobras.

[KidMach]

If you think about it......your theory regarding no increase in crankshaft hp does not hold up. Any time you reduce parasitic loss on the front end of the engine there is ONLY ONE possible path the extra power can flow through, and that is out the crankshaft. Regardless of how much or how little parasitic loss is occuring outside the driveline, the driveline loss remains constant at 17%. It does not change to a lower number as your comments suggest.

Mach On,

Kid Mach

[Verk]

Originally posted by Azure
I thought they fixed the wheel hop problems on the 01 Cobras.

I think a certain amount of wheel hop and IRS go together. On certain types of road surfaces, I would get considerable wheel hop in my 1999 Corvette with a 6 speed.

[Azure]

I'd be pissed if I owned a C5 and had wheel hop.

Then again I'd be pissed if I owned a Cobra and had wheel hop.

I guess I'm hard to please. That's why I built my 72 my way. Bad assed without any wheel hop.

Steve

[Unit 5302]

Stock engined 96-98 Cobra's are in the 11's at well over 110mph. Mid 12's with a lightly modded '01 and good traction isn't far-fetched. I am commenting on the potential of his car with serious rubber, not stock, which is why I used the phrase "with hook," and that also assumes his car won't blow the half shafts to bits in the process.

The gears will of course hold him back substantially from the 11's. The IRS was beefed up for 2001, and they cleared up some of the wheelhop, but cleared up a lot more of the problems with axles breaking so easy.

A good set of lowering springs, like the Kenny Brown kit will almost eliminate wheelhop on the IRS (according to Cobra owners who've used them). IRS is more prone to wheel hop, but I doubt you'd have a real problem with it on a Ferrari for example.

If you really wanted to get technical, 17% drivetrain loss would be what a Mach 1 would see, but the Cobra would see more loss due to the IRS. Probably another 2% or so. That puts the numbers closer to 360hp. The idea that the underdrive pullies won't affect crank horsepower isn't well thought out.

Horsepower ratings by the manufacturer are considered "net brake" meaning it takes the parasitic loss from accessories into account. Underdrive pullies remove parasitic loss from the accessory drive, and thus, directly affect engine horsepower. There are a few things that would increase rwhp that would not affect engine output such as torque converters (lighter), aluminum driveshafts or lighter wheels, but those parts are all after the engine.