SA 1100 Cranks.
Turbo Mini Forums

Ive got a 16v head, thats the race engine i'm running at the miniute, that goes to 9000RPM quite easily on a std stroke.

I want to bring the cc below 1000cc so I can turbo it and still remain in the up to 1400cc class (capacity is X 1.4 when forced induction is used)

So in actual fact I think 11000rpm isnt that unrealistic.

If something is worth doing, it's worth doing half of.

When you realize that you wont be able to use one of these cranks can i buy one off you 01smartc?

Problem 1. is the bore, Firstly to get it down to 67.3
Problem 2. is the bore once more. I don`t think the valves will clear the bore of the cylinder walls.
Problem 3. is the deck height, you will need to get longer rods. Or cause problems with the conversion kit you will most probably get from John K. Also do you trust an 8MM deck height holding your head on to the top of your engine.

Problem 4. is caused by the use of longer custom rods and the weight they add to the rotating assembly?
Problem 5. is turbo matching. Youll have to use something like a gt28 or a gt28rs. You wont see a useable boost level till 6 maybe 6 and a half grand.

All this for 230 BHP and 115 LBS/FT of torque?

Edited by Sam on 26th Sep, 2009.

Problam 6: where are you going to get valve springs to hold the valves of a k16v head closed at those RPM.
Problam 7 How do you propose to get around Piston Gs at that RPM.
Problam 8 how will you keep main bearings in the egine with the crank flex at that speed.

I like your thinking, turbo choice will be tricky. What sort of power do you want?

It's a bit of a funny one really, say you want 180bhp at 11000rpm the a you won't need really high boost to achieve this, so a GT17 might work. Problem is you will need a 'sporty' can to get to 11000rpm, which means that low down power will be massively compromised.

My mate with a 875 turbo climax in a Clan really struggles to get it off the line, and he has little traction problems, in a mini it might be difficult. and you will need seriously low gearing to ensure you don't bog down on some tighter corners.

The engine you propose may be suitable for race circuits where you never drop below 5000rpm, but for hillclimbing I'm not sure it'll work.

With our 998 turbo hillclimber we have ended upi with a compromise between power and drivability. I think with a bit more boost we could be making maybe 180bhp. But we plan to only run high boost in 3rd and 4th as we are pretty much traction limited in 1st and 2nd with over 14ftlbs of torque.

We have considered the short stroke route, but the available rpm it gives you is of no advantage with a turbo, and torque is king on the hills.

see my sig, our car works!!!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

All that development and that's all the torque it makes

Couldnt pull the skin off a rice puddin with that! Are you sure?

missed a 0. now stop being so pedantic!!

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I see what your saying. My current engine is making 176BHP and 134 ftlbs.

So I want more than this really. My championship (not sure about yours) is mostly sprints rather than hills so essentially circuit racing, but just 1 lap.

I think the head will be ok at that rpm, it goes much higher than that on the bike

So that's 0.14Ftlbs?? That's even worse....

a little off topic but as its part of the conversation, calculated valve bounce with K1100 valves/valve springs/ top caps/collets is 9500rpm. With the K1200 RS and its lower mass valves/top caps its 10800rpm.

JK

If Carling made Mini engines
it would probably be like this one!

Thats quite interesting really. Do you think it will just be a problem with valve float or will it start murdering cams?

Get a set of rods and a crank made up then. 58.5mm crank and 73.5mm bore. 10 grand and a gt2056 turbo and about. 180 bananas and 100 curlywurlys

Edited by Sam on 27th Sep, 2009.

Cheers john, so 10,000 rpm is deffo possible with my head.

Anyway is this a good target rpm for turbo? by the sound of it probs not.

Im not that clued up on turbos tbh.

Lets say im aiming for 200bhp 150ftlbs

Its not going to happen.

helpful

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

I have no doubt it would be great technical excercise to have a 1000cc big bore 16v turbo screamer however I think you may be disappointed with the finished product. I can't help but think there are more efficient ways to get the output you want/need and still remain within the reg you want. You only have to look at Wil and Ben's TT with its well proven performance.

If something is worth doing, it's worth doing half of.

In my opinion (and it is just an opinion) worry a little less about the bhp figure and concentrate on the torque figure. BHP is just for bragging about down the pub but torque is what you actualy need/feel when out on the road.

One well known local hillclimber used an Arden 8 port with a 51mm crank to get 849cc and that would turn 13K, I gather. A short stroke 3 bearing engine is fine as far as balance and stiffness are concerned. Stupidly high revs are a thing of the past, the original minisprint hit 12K in an engine with every (bodge) mod thrown at it. Cue running very high octane, mega sprint cams and serious compression ratios. Oh, mateys 13k 850 did about 4mpg....

The torque comments are totally valid, it would be better to use low revs, high boost and long stroke....gear it properly.

Another thing limiting you would be the flywheel/clutch. It would need to be a very special piece of kit and at that speed, may give a bit of a lazy response....if you had one big enough not to explode.

Reading back through the threads, there are a fair amount of cynical pricks on here, but there are also a lot of bullshitters.

Read your Vizard and build something really silly. My thought is that you won't get the fuel to make it happen. Unless you run avgas.

BAC

Here's a bit of fuel for the fire, my K100 980cc build at 20 psi boost

Just 8000rpm to get to 200hp.

EDIT: added units to calcs

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Edited by Paul S on 28th Sep, 2009.

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