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pneall · #1 (**permalink**) 03-27-2007, 07:31 PM

Brett,

Well done and congratulations. As you are running the Corvette motor it will be interesting to see what its like on the dyno in std trim. Make sure you get a good tune before you do too much WOT action.

Have fun

Rebel, If Brett is running the 3.46 Ford diff he will be doing about 1500 rpm in 6th for 110kph.

First is good for 70 odd kph and rubber can be left in first, second and third if they are street tyres.

Phil

Rebel1 · #2 (**permalink**) 03-27-2007, 07:54 PM

Thanks Phil, I'm running a jag at 3.31 so that gives me some idea what I can expect.

The L76 I'm guessing will be similar to a healthy LS1 maybe a bit more torque down low.

Thanks loads

pneall · #3 (**permalink**) 03-27-2007, 08:00 PM

Rebel,

I would expect the L76 to have good lowdown torque.

Be careful with the exhaust design. I have 1 3/4 side pipe primaries and lost a lot of torque down low

Thankfully I dont stay there too long

Regards,

Phil

Rebel1 · #4 (**permalink**) 03-27-2007, 08:04 PM

Would you recommend 1.75 primaries?

Thanks

pneall · #5 (**permalink**) 03-27-2007, 08:10 PM

Rebel,

I think the issue is the side pipe design.....just not as good as a properly designed under car system with cross overs and equal length pipes....at least at part throttle applications.

However sidepipes do sound great.

I would have a look at the LS1 site to see what works but suspect 1 5/8 may be sufficient for a standard motor but larger may be better if you plan a cam.

Losing low down torque isnt a big deal as the Cobra is very light but you may notice it in 6th gear with the diff you are running.

Regards,

Phil

PCC · #6 (**permalink**) 03-27-2007, 08:38 PM

SNKBTE,

You've managed to sum up everything thats good about these cars i.e. photos / noise / the feeling (not the Toyota one) / the general interest by all.

Take my hat off (hard hat) to you for crossing the line - now you move into the "what can I change / improve stage"

WELL DONE

Rebel1 · #7 (**permalink**) 03-27-2007, 08:53 PM

Hi Phil, actually, I have no plans for side pipes.

I have a back problem which makes it hard enough just getting out of a cobra let alone worrying about side pipes.

I'll be running under car and the only probs I see with that are meeting the noise requirments (easier than side pipes) and the ground clearance issues.

I will be swopping out the cam after a while and it seems 17/8 is the go for primary pipes.

I differ from you fellas in the gearbox department. I'm using the tremec 600RR box which has 2.87,1.89,1.28,1.1, and a .82 fifth.

This is not terribly unlike your T56 but no 6th overdrive. Crunching the numbers tells me I'll be pulling around 2000rpm at 100klm. I'm happy with that.

In looking at the dyno figures of the L76 it seems to be awfully close to a LS2 in the low revs up to about 3500 then the LS2 just steams ahead.

Sorry bout the hi-jack but uncle phil started it

Cheers

Plums · #8 (**permalink**) 03-27-2007, 09:15 PM

As Phil mentioned, the sidepipes can really knock out some of the torque due to their short but fat size.

Ideally, for a stock LS1 (or even with a mildish cam), you want a four into one design, with a primary pipe size of 1.75 inches and length of between 35 and 40 inches. This will not be easy to acheive in a Cobra.....