Engine / Transmission. Which way to go.

[Modena]

Originally Posted by Treeve

Having two overdrive gears is a wank... especially when 5th in a 5 speed is not the same as 5th in a 6 speed. The 5th in a T5 is 0.68:1, where’s a T56 normally has a 0.8 5th and a 0.63 6th. So you’re giving up 0.05:1 in ratio in 6th and you’ve got a 5th gear for... wank factor. The difference at your quoted 1850rpm at 110km/hr with a T5 is that you’d be doing a bit less than 2,000 rpm with all the rest of your drivetrain the same. And you’d do the same revs for all other scenarios in 1-4 gears with 5th in the T56 being the standout as not having an equivalent.
Plus the T56 weighs more. A lot more.
Interested to know what you shim to improve the gearchange though - got more than a couple of LS conversions with T56’s attached that I’d love to improve. Link to an article on how to do it?
Cheers,
Treeve

pretty sure, from my calculations, that my 6th is 0.5:1. Aussie Mike built the box, he's the one to ask on technicalities.

[MKS427]

The Coyotes have been doing very well in road racing and autocross. If you are going naturally aspirated a, used Mustang, budget version of the Boss or Cobra Jet push 500 hp and rev high. Basically everything except CNC heads. If money is no object and you want big power, a new Cobra Jet or supercharged Coyote would be sweet.
If you plan on racing it, a dry sump is necessary.

[gjkrv8]

Originally Posted by Modena

pretty sure, from my calculations, that my 6th is 0.5:1. Aussie Mike built the box, he's the one to ask on technicalities.

FWIW I have the T56 but with the 3:45 diff ratio. 1st-4th are good (around town and at the track). 5th is good for cruising at above 90. 6th is useless - even at 110kph (Engine at 1500rpm sounds like it labours)

Even tried changing into 5th at Phillip Island this week at 210Kph (was doing about 5900 rpm) - no difference, probably a horsepower v Cobra "brick" aero deficiency problem :-)

Wish Mike did my box conversion as I keep changing from 4th into 5th when going for 3rd. (Then I normally spin off as am in wrong gear)

cheers Gregg

[Tenrocca]

Originally Posted by gjkrv8

FWIW I have the T56 but with the 3:45 diff ratio. 1st-4th are good (around town and at the track). 5th is good for cruising at above 90. 6th is useless - even at 110kph (Engine at 1500rpm sounds like it labours)

Need more torque greggy - I use mine quite a bit on the freeway.

[Donunder]

Originally Posted by Modena

pretty sure, from my calculations, that my 6th is 0.5:1. Aussie Mike built the box, he's the one to ask on technicalities.

Or....if you're up near Godzone, Mal Wood at Warwick is a TKO/T56 guru. Our own Mrs Flatchat (Chris) is your contact there.

They built mine with the .82 fifth and it's spot-on for the road. It's also fitted with the centre-mounted gear shift which positions the Hurst gear lever perfectly in my car.

My son's (700hp,Craig) 452 Contemporary has a similar box but with the .68 fifth which is simply too tall for anything under 120 kmh.