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Ford 8.8 Ratio Advice
Posted: Mon Aug 27, 2018 4:15 pm
by Coops
Good evening been a while since ive posted on the forum
after some advice regarding rear end ratios for road and track,
currently running the stock 3.08 ratio with the R380 5 speed gearbox,
im not after out and out acceleration as the car is driven on the road more than the track,
but want a little extra help at the track along with the supercharger,
Re: Ford 8.8 Ratio Advice
Posted: Mon Aug 27, 2018 5:28 pm
by stevieturbo
Who are ye ?
1st gear is quite short...
But generally, if you're considering from a drag racing point of view then you'd aim to make full use of 4th gear over the 1/4
So whatever mph you hope to achieve, with whatever tyre combo and rpm you have...then work out what diff ratio will best get you there.
I doubt you'd ever want to see a shift into 5th over the 1/4 with a regular manual box. But you may want to leave a little headroom so 4th can pull more than it is capable now.
Although CWP's for the 8.8 are very cheap. If you can be bothered with the work, buy a couple and try them ? But I'd guess either 3.55 or 3.73 are most likely to be best suited unless you'll use quite tall tyres at the strip.
In general I prefer a 3.55 for my own car, but I use a 3.27 because for higher speed stuff it suits better.
Re: Ford 8.8 Ratio Advice
Posted: Mon Aug 27, 2018 5:36 pm
by Coops
Hi Stevie,
I was looking around a 3.44 but there isn't such a ratio for the 8.8 like the old capri atlas ratios, 3.55 seems the closest,
225 50 15 hoosiers think that works out around a 26" tyre ???
Re: Ford 8.8 Ratio Advice
Posted: Tue Aug 28, 2018 4:19 am
by unstable load
What ratio 5th gear do you run? You could get a bit more out of the box there.
The R380 in the V8 Disco2 has a 0.73:1 5th and the diesel is 0.77:1.
Ashcrofts sell the gear kit.
Re: Ford 8.8 Ratio Advice
Posted: Tue Aug 28, 2018 8:46 am
by Coops
R380 2wd as used in the morgan plus 8 v8 mate
Gear-----Ratio
1st-------3.321
2nd------2.132
3rd------1.397
4th------1.0
5th------0.77
Re: Ford 8.8 Ratio Advice
Posted: Tue Aug 28, 2018 10:26 pm
by stevieturbo
Coops wrote: ↑Mon Aug 27, 2018 5:36 pm
Hi Stevie,
I was looking around a 3.44 but there isn't such a ratio for the 8.8 like the old capri atlas ratios, 3.55 seems the closest,
225 50 15 hoosiers think that works out around a 26" tyre ???
Plenty of online gear calculators for you to play with.
cant see that size being 26" tall...maths says more like just under 24"
A 3.55 would just take you shy of 140mph in 4th gear at 7000rpm, 120mph at 6000rpm ( ie 19.7mph per 1000rpm )
you can get 3.27, I've seen some say also 3.33 and of course 3.55
Re: Ford 8.8 Ratio Advice
Posted: Tue Aug 28, 2018 10:37 pm
by stevieturbo
A new crush washer, front pinion nut and some shims at the back to adjust lash would be a bare minimum to swap., and maybe a rear gasket.
If all bearings are good, really not a lot of point in changing them, although it can be a little awkward to get the old ones off. Unless you're changing the front pinion bearing, there's no need to disturb the pinion seal...they can be a bit of a ballix to install too.
I've re-used the pinion nut before too, just use loctite on it but new nuts come with a coating.
https://www.summitracing.com/int/parts/ ... /overview/
Although even on ebay you find loads selling second hand ones for around half the price. From a packaging/safety point of view...I'd be buying new though. Think they might actually come with a new nut and crush washer.