GT186 - 4.6 or 4.89 final drive and which exhausts?

[Donnie]

........Now, if I go 16 / 46 I end up with 4.89 final drive and I think i already have a stretched 80 link chain.

However if i go for the 17/46 I can get a 4.6 final drive and need to get a 81 link chain.

(I could go 4.8 ratio but then thats a 48 rear / 17 front and 82 link chain and not sure if its much advantage over the 4.89)

I have a standard GT186, albeit with a 115 conrod, 30 PHBH and MB Clubman.

I have the Li150 box and have tried 16/46 and 17/46. I found it struggled to pull 17 and that 16/46 is much the better of the two.

But, I do think that the ideal set up is somewhere between the two.

maybe 17/48 IS the way to go! But then it's going to be quite exhaust dependant too?

eg Richard Taylor seems to advocate 17/46 using a franspeed pipe so maybe that will rev on further and pull the 4.6?

[Lambretta Sash]

Eden, its a bolt on kit I've been abusing on my original GP and playing with pipes Best bit was it make same power with clubman as in scattering test. tried 4.6 but needs 4.8/5.0 to give that kick in pants with 12 tq, TT pipe was put on and made good power/tq increase which i like i can see 30 hp 80 mph easy with correct gearing and port timings and may well do that but it is original case untouched and im reluctant to modify casing.
I'll put another clutch in, drop gearing and see what it does

[Donnie]

Feckin eejit! Was wondering why my stretched 80 wont fit, i miscounted and have already fitted a 17 tooth front!

[Rich_T]

Feckin eejit! Was wondering why my stretched 80 wont fit, i miscounted and have already fitted a 17 tooth front!

If you use a GT chain tensioner you don't need stretched chains any more.

[Donnie]

Yep got one of your tensioner a Richard:) was thinking I could get the longer chain and that gives me more options

[a.j]

I've got two mates with Li150 boxes running gt186 kits. I'll find out tonight. I've got an iron 225 with a taffy exhaust and they fly past me no bother.

that would be great mate if you can

15/46 with BGM Clubmans mate. 26 delly carbs through the airbox.

[dutch]

I run 17-46 with 42mm clubman, 26mm dellorto through airbox gp150 gearbox, very happy with this set up.

[Donnie]

I've got two mates with Li150 boxes running gt186 kits. I'll find out tonight. I've got an iron 225 with a taffy exhaust and they fly past me no bother.

that would be great mate if you can

15/46 with BGM Clubmans mate. 26 delly carbs through the airbox.

15? christ they must be screaming i would have thought

[Donnie]

Lot of people just using normal clubmans on this kit, i honestly thought I'd really need a jl / taffy / franspeed to get the most out of it but might start on the clubby and go from there.

[Rich_T]

I don't use 15 tooth primary drives with any small block gearbox combination