The Lotus Grand Tourers

camyug · Post by **camyug** » Fri Jan 20, 2006 18:40

Crown and pinion from IFS 4x4 does work in Excel housing, they're identical in spec, I had to change to bigger bearings because the Truetrac was designed for the 4x4 which has 50mm ID outer bearings, but it all goes in no problems! If all you want is to change the ratio, the 4x4 crown and pinion will fit the standard Excel diff.

lucky lichfield · Post by **lucky lichfield** » Sat Jan 21, 2006 20:18

hi camyug,

checked these before without luck, but then clicked on one of the links:

http://www.off-road.com/toyota/taco/tec ... codes.html

with the reference to tacoma axles/ratios for 95-99 tacomas and they list a 7.5" 3.42 ratio 2 pinion lsd. is this the one you've got.

if this is the baby i'll be a very happy bunny.

cheers

camyug · Post by **camyug** » Sun Jan 22, 2006 21:32

hi lucky
It wasn't from a Tac, but that's the same ratio, should think Toy just carried it over from F series 4runs, if it has the same number of mounting bolts to diff centre and pinion is 27 spline, it'll fit.

Looking at the links, there's a ref to IFS Tac of 26/27 spline, so being 7.5", this seems to be the same spec. But:

'FRONT GEARS

Like older IFS Toyota’s, The Tacoma uses a 27 spline, 7.5” front differential. But unlike the older model trucks, the Tacoma uses a hi-pinion differential. Hi-pinion (above centerline) axles are ideal in front applications because they provide a substantial increase in strength compared to a traditional front-mounted low-pinion (below centerline) axle. This is because hi-pinion axles use reverse-cut gears. The name “reverse-cut” indicates that the sides of the gears teeth are cut the opposite of standard gears, what is normally the coast and the drive side is reversed. Hi-pinion differentials are often erroneously referred to as being reverse-rotation. Although the gears are cut opposite to standard gears, they still rotate the same direction. This makes for proper gear engagement resulting in as much as a 15-30% increase in strength.'

So gear engagement is the reverse with the Tac, but that's just an engineering issue. See photo of my original and replacement then compare the photos here:
http://www.off-road.com/toyota/projects ... index.html

My setup:
http://img378.imageshack.us/img378/7322 ... rac3wq.jpg

http://img470.imageshack.us/img470/7905/diffin7zj.jpg

Photo prior to fitting shows original Excel diff internals, new Truetrac centre and on the right and bottom the IFS Toy 4run ring and pinion, count the teeth as compared to original.

Tac setup bolts on the same side as Excel/4run, so even though reverse gear cut, you'll still go forwards!

lucky lichfield · Post by **lucky lichfield** » Mon Jan 23, 2006 16:54

Hi camyug,

Thanks again for the extra info.

Also spent some time checking through the U.S. CelicaSupra site which has a wealth of info on mk2 Supra and all sorts of mods and upgrades.

Seems the 3.42 and 3.58 ratios were available in both 85 (on?) celica (non lsd) and 2wd 5 spd hilux trucks/pick-ups. Also a 3.07:1 ratio was around on the 2wd 87-92 4spd hilux. There are a couple of guys there running the 3.42 and one guy on the 3.58 on various 300+ bhp modded cars.

Re the reverse cut gears, like the idea of the extra strength aspect vis a vis my v8 conversion. When you mention an engineering issue, what sort of extra work is involved over and above fitting the standard spec ring gear.

Would the garage that did your work be able to do this if I sent them a diff, ring gear + all other bits etc. Have also asked the guys in the U.S. if they have had any experience of this.

Thanks again, you can't believe how much trawling I've done on the net to get to this point.

CORRECTION: been advised that the 3.07 ratio was on an 8" ring not 7.5".

camyug · Post by **camyug** » Mon Jan 23, 2006 17:48

hi lucky
yes, one of the celica sites was where I picked up the Truetrac mod.

As regards the reverse cut, when I say it's an engineering issue, I mean for Toyota. You can just bolt it in the same way your standard ring and pinion goes, just compare the photos. The ring is held on by 12 bolts I think, with simple retainers that you can re-use, the pinion will need a decent puller, most decent firms can do the hard bit.

If you want to use my guys no problem, they're near Oxford, not a fancy set up but good.

Finding out this stuff does take a ridiculose amount of time, let alone the research for a six speed and supercharged conversion! But then again you don't do this sort of thing because it's sensible, do you!?

lucky lichfield · Post by **lucky lichfield** » Mon Jan 23, 2006 22:37

Cheers camyug.

I'm 1 hour down the road so to speak in Uxbridge/Heathrow. If you don't mind would be great to get your guys' details. If I go the reverse cut way will they know what's required etc compared to 'normal' cut gears.

Should you ever need a really excellent Rover/TVR v8 mechanic I will be happy to reciprocate. Not a fancy set up like you say, but absolute genius.

Guess if you're gonna go the not sensible route i.e. a rare supercar from a manufacturer with grand prix winning heritage and lots of power, the Excel is probably the most sensible, reliable, economical way to go....toyota parts, galvanised chassis, plastic body, guigaro interior, excellent handling etc etc.

camyug · Post by **camyug** » Tue Jan 24, 2006 20:32

GEARS R US 01993 851215

There out in the middle of nowhere in a shack, but they don't charge stupid prices and know their stuff.

The reverse cut makes no difference. But double check that the spec is the same, I fitted a ring and pinion from a 90 4Run which I can vouch for.

lucky lichfield · Post by **lucky lichfield** » Tue Jan 24, 2006 23:27

great stuff thanks.

will let you know how i get on.

bodgitostrich · Post by **bodgitostrich** » Wed Jan 25, 2006 01:15

just aquired an LSD from mike at the weekend, plus a set or rear poly bushes, so hopefully i'll start to become the drift king in the lotus, and not the 360 kid...