So my mini is currently under going a resto. I'm currently working on the body but I'm just planning a bit of work to the engine and gear box and was wanting some advice. It's a 1380 1100s motor with a RE13 cam, 1.5 high lift rockers, stage 2 maniflow LCB extractors, hif44 which I'm going to put on a re7 russell engineering inlet manifold. I'm wanting a fast off the mark mini to drive round town. My question is what diff ratio would be idle for a motor like that and would a lightened flywheel work well with this combination. Cheers, Tom

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If its yours, customize it !

I am running almost the exact same setup. With this much power a standard 3.44 diff (Cooper S) is perfectly fine, I have absolutely no complaints about 3.44 and would put one back in the next rebuild no hesitation (although perhaps a LSD instead). Take off is good and freeway cruising is a sane 4100rpm (110km/h).

If you do a lot of freeway miles then maybe a taller 3.1 or 3.2 but maybe at the sacrifice of take off speed. If you have in access of 100bhp then 3.2 may not be too bad.

Definitely I'd not go the other way (3.647 or shorter) but Dr Mini runs one and he seems to like it, but I don't think he runs many freeway miles? I'd be deaf running more than 1 hour at 4400rpm at speed...

3.44 at the end of the day is the best compromise.

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Lillee - 1969 Morris Mini K

If off the mark speed is where you want the power, the general consensus seems to be to lose the 1.5 rockers. Certainly the case with my own motor which seems to be a similar spec. Great for up top, baaad for off the line.

Yeah now I run 1.3's too

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Lillee - 1969 Morris Mini K

My 1412 is good off the line, S gears and 3.44 diff, with either single HS6 or 45 Dellorto.
It has an RE13 with 1.5 rockers. Set the rockers at .019" not .016" or it WILL be worse off the line.
I'd not go back to 1.3 rockers, I like my bigbores to have a little top end sizzle.
BTW its peak torque (113lb/ft) was at 4000-4500 and peak power (113.6HP) at 6500. Measured on a proper Froude engine dyno, not extrapolated BS from a rolling road.

re the 3.647 diff yes I use one- but it's in my 1360; it makes up for the bigger RE282 cam and 1.5 rockers. Like Lillee says it doesn't see much freeway. I put it in for Wakefield Pk track days and not yet taken it out. But it's great around town, it pulls good from 40kmh in 4th on part throttle.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Yeah having driven Kev's Haha, it is a furious monster off the line... since I already drive a 120hp mini this is saying something

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Lillee - 1969 Morris Mini K

So 3.44 you guys reakon. I hardly ever take it on the highway, only done it once in the 3 years I've owned it. The only reason I would take it on the highway is for some track days at wakefeild or something which would be less than once a year. What are your opinions on lightened flywheels on this set up? I understand that it will need balancing with the crank etc.

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If its yours, customize it !

Yep I'd go a 3.44 for a 1380 roady every time. Only reason I put a 3.64 in my 1360 was to give a bit more 4th gear pull on the Wakefield Pk straight.
As it happened I had a thrust washer problem there (not enough crank endfloat) so it went home on a trailer. Not been back since.

Lightened flywheel is good for either road or track (I do them) but if it's going to rev to 8000 or more go buy a light steel one, and a light steel backplate.
Yes the flywheel needs balancing, but not necessarily on YOUR crank. I get mine done at GR's, he has an already balanced crank there for this purpose.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Okay. Thanks heaps for that

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If its yours, customize it !

What size wheels are you using? I'm on 10 inch, 1360, RE13, and 3.4 diff with lightened cast iron flywheel, and it pulls well off the line. May be helped by the 3 synchro sc/cr Mk1 S box which allows 1st gear to run out to an astonishingly high mph.

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Slide
1965 Mini Van (1360)
1970 Mk2 Cooper S (1310)
1978 Rover SD1 V8 (4.6)
1996 Land Rover Discovery V8 (4.0)

I'm running on 13x7. To start off with it was just for looks but I've grown quite fond of them. I find 10's to skid a bit in hard cornering and in some cases it feels like the tire rolls more than the low profile 13's. Also more traction when taking off. I know they add strain to parts of the mini but to be honest when arnt things breaking and wearing out on our minis haha.

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If its yours, customize it !

Really? I don't have any of the problems you're reporting running 10's and A008's at that. They hug the road quite well all things considered. YOu must really be throwing your car into corners at uncomfortably high (read illegal) speeds

I've driven cars with 13's and they just feel slushy, dont flame me, I tell it like it is. Minis just feel more agile on 10's. But I agree at some point 10's will give up on grip but only really when you are running ridiculous hp, say 200bhp+ (Starlet GTi conversions etc). But honestly, A series no blower, 10's are more then enough.

10's with A032Rs, if the Group N guys are running it, it can't be half bad! (yeah yeah never mind the rules)

Larger diameter wheels slows you down. It's a known fact, the larger the diameter wheel the slower the take off.

13x7 Look porn though

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Lillee - 1969 Morris Mini K

Josh's Starlet Mini (200+ HP ATW) had traction and handling problems with 13" wheels and A048Rs. So he dumped them in favour of 10x6s with A032Rs.
Much better he says, but he's sold it now.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Well you learn something new everyday

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Lillee - 1969 Morris Mini K

So He Under Tyred a 200+ HP car to Cure a Problem with the Subframe, Chassis setup ?

Gee, Alarm Bells Should Be Ringing There Don't you Think!!!!!

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