the best differential ratio

[Tenrocca]

[quote=1 TUF AC;1324593]

Originally Posted by 1 TUF AC

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I went for a dirive today and I think found out why I couldn't get 100km out of second gear. It looks to me that my tacto is out buy at least 500rpm. Because the calculator say I should be reving 2000rpm @ 60kph in 4th gear but I am reving 2500rpm. normally I don't rev over 6000rpm but today i rev it to 7000rpm but the tuner sad he set the limiter to 6300rpm. And the gps says i did 100km out second so I'm pretty sure my tacto is out or my limiter is off and I have 4.3 diff gears. It definitely went a lot better when rev it That little bit more. i have a vdo tacto maybe it needs to be reclabraded or something. I might go past the tuners and get them to plug the laptop in to see if the revs Maching up with the tacto. At idle my car sits at 1100prm but it doesn't sound like it idling that fast. I am 90% sure my tacto is out but it could be something else.

You or your tuner should be able to plug into the obd2 port and get a RPM straight off the CPU to compare to the gauge.

[1 TUF AC]

when I was looking to buy a cobra I noticed a lot of people are running a open differential instead of a limited slip differential. they were saying that LSD differentials in cobras create two much understeer when accelerating through a corner because of the short wheelbase. Has anyone out there experienced that? because if I decide to change the differential ratio I might as well put a good 1 way, 1.5 way or even a 2 way LSD centre as well.

[Mother]

I chose to use 3.5 finals with an Auburn Ratchet Spool. The Tires are Nitto 555 with 315 / 35 / 17's for rear tires. The motor is an extensively modified 460. Plenty of torque. Lots of horsepower, But pilled at 5200, because I am using a re-worked 650 holley. The carb is somewhere north of a 770. I need the spool to get the power down to both wheels when pulling off a corner.