22 replies to this topic

[Nirrmal]

how long do you need it to last.. is the gearbox even capable of handling those kind of loads... and how deep are your pockets

 

I want it to be reliable, right now I've got an NA setup with about 6k in upgrades. +0.60 pistons, MED RS cam (270), supporting mods such as a new radiator, new valves and valve springs, xpin diff, new clutch and brake lines and pumps, lightened flywheel and crank (metro block, head and crank). I am confident that this setup will make around 100hp but is there any way i can get past 150 without force induction? 

Edited by Nirrmal, 02 September 2024 - 12:38 AM.

[Nirrmal]

I am not sure, as I am a dinosaur in all this, but back in the day as a normal mini user, ie not bleeding edge developments, i raced and sponsored by Rover, we used to believe or be told the mini crank could only really take about 150 BHP "reliabley", I was turning around 120 BHP, which with a straight cut gearbox etc amounted to around 105 BHP at the wheels... I was pulling around 8500 to 9000 revs, after about 200 miles, the engine was toast, but i do know times have moved on

what cam were you using to rev up to 9000, is it possible to get a cam that will rev up to 9k that isnt too lumpy for road use? 

[StefanMini]

If you want reliable power just go for a Honda Vtec conversion ore something. I think that's much cheaper too.

[hazpalmer14]

how long do you need it to last.. is the gearbox even capable of handling those kind of loads... and how deep are your pockets

is there any way i can get past 150 without force induction?

Not really unless you’re looking at going for a 7/8 port head. 7 port you’d need a bigger cam. 8 port requires its own special cam and rocker gear. You could go for a 16v head such as KAD or the BMW K head.

The easiest way to get 150hp is to turbo it. You’ll have a great torque curve it won’t be highly strung to make the power either

[MiniMadRacer]

I was running a Kent 296 if I recall, and yes it was an out an out racer not a road car

[DeadSquare]

Back in the 1960s /70s, people used to talk about having 125BHP from a 5 port full race engine.

 

I only ever saw one, on a dyno, that touched that, and I mean touched before the power fell away.

 

Full race engines are lumpy, period.  That is not a problem in a race, once you have got off the line, 25 or so times in a season, but trying to launch a full race car gently, 25 times on a shopping trip and after a month you start thinking about home delivery.

 

I had an 8 port Arden head on Webbers that never touched 140 on the dyno, so I don't think that even with fuel injection and electronic engine management, you could get 150 BHP that you can drive on the road.

 

9,000 rpm cam's peak power are like the Eiffel Tower.  What you need on the road is something like Ayers rock.

 

As others have said here, go for forced induction.  It is a more effective and less expensive way of getting usable  power out of an A series engine.

[stuart bowes]

just for the record do you mean bhp at the flywheel or at the wheels

Same question to OP and deadsquare

 

it's all academic anyway as they say but nice to make sure we're all talking about the same thing 

 

and, just for my own curiosity just how much can a standard gearbox actually reliably take

Edited by stuart bowes, 02 September 2024 - 10:44 AM.

[DeadSquare]

I should have been more accurate, I was referring to Flywheel readings.

 

In my experience, the Mini gearbox can transmit a lot of power without failing.  What bottom gear on the lay shaft doesn't like is dropping the clutch with as little as100 BHP on tap, and loosing a tooth.

 

I have also seen the web split from the diff side of the box on occasions when full power has been available on changing brutally from 1st to 2nd.