What's your Cobra's top speed?

sambo · #1 (**permalink**) 10-07-2008, 09:43 PM

Les, are you suggesting the bigger the cam, the higher the peak torque delivery?

Rebel1 · #2 (**permalink**) 10-07-2008, 10:13 PM

Quote:

Originally Posted by sambo

Les, are you suggesting the bigger the cam, the higher the peak torque delivery?

Nooo, not at all, but I am referring to where the peak torque occurs in the power/rev band.

On the track you spend most of your time in 2nd and third gears at higher RPM.

Not so on the street.

sambo · #3 (**permalink**) 10-07-2008, 10:57 PM

Quote:

Originally Posted by Rebel1

Nooo, not at all, but I am referring to where the peak torque occurs in the power/rev band.

That's what I meant.

Rebel1 · #4 (**permalink**) 10-07-2008, 11:05 PM

I think Sambo that this question can be answered by any of the 6ltrs LS$ ( because Sambo has a 6Ltr) owners who were at the nationals.

What rear end do they have, what gear box, what tyres, and how did they perform of the track.

If they then also commented on the same car as a road car we would all have something real to compare rather than theory.

Who had 6Ltrs of glorious chev/holden power at the Nationals?.

acecob · #5 (**permalink**) 10-07-2008, 11:19 PM

How long is a piece of string,
It's not how fast you want to go ,it's how long do you want to spend in the lockup

Rebel1 · #6 (**permalink**) 10-07-2008, 11:37 PM

Quote:

Originally Posted by acecob

How long is a piece of string,
It's not how fast you want to go ,it's how long do you want to spend in the lockup

And that's why I suspect the early to mid three gears are good for the street. It's not about top speed. It's about a balance of performance,noise, comfort, and fuel consumption.

All of the Cobras I've driven have had the mentioned transmissions and rear ends ranging between 3.3 and 3.9 with engines in the 350 - 400rwhp mark.

It is very noticeable to me that those road cars using 3.3 or 3.5 are more pleasurable to drive on the street. You don't have to rev the snot out of them. You don't draw attention to yourself just taking off from a set of lights. Yet the same cars will fry the tyres at will.

Keep in mind also, that wheelspin is not necessarily fast, traction has always been a problem with these cars.

Track work however is a whole different story.

Harrymac · #7 (**permalink**) 10-08-2008, 12:47 AM

I can't tell you who, I can't tell you where and I can't you when - all I can say is, it is an LS1/6 speed.
If I am questioned, I will say it is hooked up to a battery drill in WA.???????

Bryan Wilson · #8 (**permalink**) 10-08-2008, 02:10 AM

How about this

Beejay · #9 (**permalink**) 10-08-2008, 02:21 AM

There was at least two 6Ltr T56 cars at the Nationals, Phil N was one.

I could do almost the whole of Wakefield in 3rd using a 3.54 ratio. When this diff blows up one day I will go for 3.9's.

Ben

ROUSHAC · #10 (**permalink**) 10-08-2008, 03:38 PM

Quote:

Originally Posted by Bryan Wilson

How about this

198 MPH - must have been Dick Smith's speedometer.

jhv48 · #11 (**permalink**) 10-08-2008, 06:58 AM

Wasn't the question "What is your Cobra's top speed"?

Mine is around 150 mph before it becomes airborne.

cameron02 · #12 (**permalink**) 10-07-2008, 10:17 PM

With modern transmissions (overdrive) I reckon you might as well go around 4 to 1. I have a 3.91 to 1 and revs are still quite low on the freeway thanks to overdrive. Unless you want to break the land speed record I cant see the point in installing tall gears (like 2.92 or 3 to 1) with a modern transmission.

Rebel1 · #13 (**permalink**) 10-07-2008, 10:51 PM

Quote:

Originally Posted by cameron02

With modern transmissions (overdrive) I reckon you might as well go around 4 to 1. I have a 3.91 to 1 and revs are still quite low on the freeway thanks to overdrive. Unless you want to break the land speed record I cant see the point in installing tall gears (like 2.92 or 3 to 1) with a modern transmission.

That depends I feel on what first gear ratio you have. If for instance you had a TKO500, earlier 3550, or T5 with a 3.27 first you could/would only use it for pulling stumps. It would be way too short and cause so much wheel spin one wouldn't use it. It would be faster and as effective to start in second.

Even a 2.66 first T56 with a 3.91 rear will give you tyre frying take off so may be more effective with a 3.7 rear. I tend to feel the more torquey engines would be better off the 3.5 or 3.7.

At the other end of the rev range it would be cam dependent. ie a T56 with a .74 fifth and 3.91 rear will be pulling 2100rpm at 100KPH.. In 6th at the same (legal) speed it would be at 1420rpm so even with a mild cam it (6th) may well not be truly usable until you got well into the 130KPH mark at 2150rpm.

All very personal tho.