Right, some if not all of you will know me as the nutter with the viper engine, well, i need to order the crown wheel and pinion and i'm stuck as
to what ratio to order, its a ford mustang irs 8.8 in the back so the ratios are
2.45
2.73 the one i was after but been adviced against but i would still like it if its ok.
3.08
3.27
3.55
3.73
4.10
tyres on the back will be 295/30 18, or 17 if it makes a difference, but would like 18"
weight of car 900kg ish
t56 gear ratios
2.66
1.78
1.30
1
.74
.50
max rpm = 6000
engine is dodge viper 8.3 v10, 550hp ish, 575Ib/ft ish ( been remapped so don't know exact yet but about this )
the t56 isn't the best gearbox for fast gearchanging, so thats why i like the idea of the 2.73, gives 61mph in 1st and 160+ in 4th, leaving the
5th and 6th as just cruising gears, it may pull 5th i don't know
the question is, will the 2.73 be to tall even with all the power, don't want to bog down in first, whats the chances of it pulling in 5th at
all.
over to the experts
if first gets you to 60 at 6000rpm, then even idling is giong to be 6 or 8 mph, which might be annoying in slow queues. Id aim for lower gearing and
then just set off in second if you wanna avoid a slow change, but each to his own.
have you driven a std viper ?
that would give an indictation of what you might require .
youll spin the wheels whatever with bugger all weight over the back
a viper is geared for 49mph in 1st and weighs in at about 1600kg, so i guess at only 900kg ish 61mph in first would be an ok gear, of doesn't it
work like that!!!!
if i get stuck in traffic i'll just have to pump the clutch a bit.
Agree with Joel, go for a fairly normal 1st and pull away in 2nd if you don't want to change. Two cruising gears seems excessive - if you don't think it'll pull in 5th then it certainly won't in 6th!
quote:
Originally posted by JoelP
if first gets you to 60 at 6000rpm, then even idling is giong to be 6 or 8 mph, which might be annoying in slow queues.
Not going to make any difference what ratios you use --- all academic as on road tyres you will get so much wheel spin in the lower gears it will be
uncontrollable.
Sometimes less is more.
A Standard Viper won't hit 60 in first.
And general concensus used to be that you should change in the 5200 rpm (or less) range, because power starts to tail off above that point (although
it's not exactly wimpy even there). Most of what makes a viper though isn't 0-60 time it's 30 to 100+, flooring a viper in 2nd gear at
2000 rpm is really a very impressive experience.
Bear in mind a viper has wheels that are 13 inches wide on the back, and you'll still spin the wheels through multiple gears if you don't
take care with the throttle.
They also pretty much define throttle on oversteer, I don'y know anyone with a viper who hasn't spun it on standard roads by touching the
throttle too early going around a bend.
I sold my Viper 4 or 5 years ago, so I don't know what the current gen ones are like.
[Edited on 28/6/07 by ERP]
quote:
Originally posted by smart51
The Viper idles at 500 RPM. 60 MPH at 6000 RPM is 3 MPH at idle. Plenty.
With that much power you may be better off working the other way, something like 1500rpm in 6th trundles along at 70.
The point about speed at idle is very valid, nothing worse than constantly playing with the clutch at very slow speeds, I would treat it as 5 speed
with crawler gear !
quote:
Funnily enough two of us had a startlingly similar conversation about the viper engined car that was on display @ Newark show recently, that while you can never have enough power on the one hand, there are times when you will start encounter issues getting such amounts of power to the tarmac.
Yep looked at that 
High-light of my day that.
Just a pointer but is the T56 box able to take that amount of power?.
I would have advocated using a TKO600 BUT, I could be wrong.
quote:
Originally posted by Blakey_boy
Just a pointer but is the T56 box able to take that amount of power?.
I would have advocated using a TKO600 BUT, I could be wrong.
quote:
Originally posted by Blakey_boy
Just a pointer but is the T56 box able to take that amount of power?.
I would have advocated using a TKO600 BUT, I could be wrong.
quote:
Originally posted by Blakey_boy
Just a pointer but is the T56 box able to take that amount of power?.
I would have advocated using a TKO600 BUT, I could be wrong.