Just test drove an 03 Cobra

[Jay 02 TA ws6]

Originally posted by fastTA
LS1 motors are far superior to the ford motors. The LS1 heads are essentially a race designed head. Even though Jay is 20-25 RWHP less than the Cobra, he would pull on it.

Oooooh, Kev, I dunno... that's a bold claim. Stock Cobras can trap anywhere from 109-113 from what I have seen... from a 70 punch, it would be real, real tight.

[Jay 02 TA ws6]

Originally posted by Jay 02 TA ws6
I guarantee that me vs. a stock 03 Cobra would be a heck of a race, man... I am probably still the underdog, but I would not get whooped on... not at all.

Let me expand on this...

... I know how this board feels about "playing around" on the street, so I never shared this story with you guys. At night I went out to the highway with a buddy of mine who has a 01 Z06... pretty stock, just CAI and catback.

We dropped the hammer from 70, and well... here is what happened... I beat him to the punch, so I got a quick advantage, but then he kept up (duh)... All the way to the top of third, neither one of us pulled on each other. Then I lifted to shift into 4th, and he lunged ahead (he still had another 500 RPMs or more to turn), once I got back on the power, I slowly faded to his rear-quarter panel all the way through fourth gear. I shut down at the top of 4th gear, barely at his rear bumper. He still had more left in 4th gear, and I would have gotten sluaghtered in 5th.

If a Z06 can't destroy me, there is no way an 03 Cobra is going to.

[fastTa]

Originally posted by Jay 02 TA ws6
Oooooh, Kev, I dunno... that's a bold claim. Stock Cobras can trap anywhere from 109-113 from what I have seen... from a 70 punch, it would be real, real tight.

One thing for sure, it would be fun to go find out!

Oh yeah........not that I am condoning street racing or anything.

[poopnut2]

I don't see how a GM head is superior to a ford head. I guess in a way you're right but if you think about it it's only due to the larger valves and ports. Size for size the ford head is more efficient then the GM head.

As for the ZO-6 story, sounds like your car is pretty fast to be keeping up with that. I'm not saying this like I'm 100% sure because number racing is for people without cars but a stock cobra dyno's higher then a ZO-6 and starting at 70mph really takes away your weight advantage. For instance, someone close to my family has a powerstroke deisel which weigh close to 9,000lbs. He has a power programmer set to 125hp and slowly pulled on a stock lightning on the freeway which weighs less then 5,000lbs.

Once again, that's just number racing though.

[Jay 02 TA ws6]

You're right about weight not mattering as much when you are going from a roll... aerodynamics becomes important too.

But, from a roll, a Z06 is one of the strongest cars out there. A stock 03 loses to a stock Z06 every time.

That Z06 dyno'ed 345 rwhp, and 350 rwtq... with me dyno'ing 345 rwhp and 360 rwtq, weight and aerodynamics are why he beat me.

[poopnut2]

Originally posted by Jay 02 TA ws6
You're right about weight not mattering as much when you are going from a roll... aerodynamics becomes important too.

But, from a roll, a Z06 is one of the strongest cars out there. A stock 03 loses to a stock Z06 every time.

That Z06 dyno'ed 345 rwhp, and 350 rwtq... with me dyno'ing 345 rwhp and 360 rwtq, weight and aerodynamics are why he beat me.

Good god. Everytime I see ls-1 dyno numbers I get jealous. It's not fair how easily they gain power. I guess that's the case with the cobras too though. And even the mach 1's to a smaller extent.

[fastTa]

Originally posted by poopnut2
I don't see how a GM head is superior to a ford head. I guess in a way you're right but if you think about it it's only due to the larger valves and ports. Size for size the ford head is more efficient then the GM head.

As for the ZO-6 story, sounds like your car is pretty fast to be keeping up with that. I'm not saying this like I'm 100% sure because number racing is for people without cars but a stock cobra dyno's higher then a ZO-6 and starting at 70mph really takes away your weight advantage. For instance, someone close to my family has a powerstroke deisel which weigh close to 9,000lbs. He has a power programmer set to 125hp and slowly pulled on a stock lightning on the freeway which weighs less then 5,000lbs.

Once again, that's just number racing though.

Well the 15° LS1 valve angle alone is a huge performance jump from the 20° valve angle of the 4.6 head.

But there's alot more.....

The LS1 head has only 2 valves per cylinder where the 4.6 head has 4. So when you look at the total surface area of the valve comparison the Cobra has approx. 67% more intake valve surface area and 66% more exhaust valve surface area. So the larger valve theory is irrelevant.

Additionally the LS1 head has a unique tall narrow runner which allows port volume to remain low while velocity is huge, and the LS1/LS6 intake manifold is engineered to function as essentially a part of the intake runner. Ford didn't think of doing this. The LS1 valve bowls are also much better than the Cobra head. They allow plenty of swirl once the a/f is entering the combustion chamber and with the port bias being much less than the Ford head, turbulence is greatly reduced in the LS1 intake runner.

Velocity of the a/f mixture into the combustion chamber is basically the ticket to "stuffing the cylinder" and thus making more HP, and the LS1 head is far better at doing this than the Cobra head.

In all fairness both cars are very awesome and very quick and I have to admit that I love the exhaust note of the Stang's!

[fastTa]

Interesting little article:

http://www.dynoperformance.com/artic...ails.php?ID=28