8 replies to this topic

[Mini_Tom94]

Hi Guys, I'm interested in modifying my Cooper to 90-100bhp whilst keeping the A-Series engine. I'm trying research different ways of doing this. I'd like to know how you guys would do it? I'll be using it has my daily driver so I'd like it fairly economical (if possible) and I want some power there when I put my foot down. I'd appreciate everyone's ideas.

Thanks, Tom

[Turbo Phil]

Are you planning on keeping the standard single point injection ? If so you're going to struggle to get those figures. 80 hp or so would be more realistically achievable.

 

Phil.

[Ethel]

Turbo.

 

Power = Air consumed:

 

You can improve engine breathing with a head, manifolds & exhaust, that'll give you more power and more economy, especially if you maximise the compression ratio.

 

You can bore the engine bigger which will give you proportionally more power, with some tailing off as you reach the flow limits of the bits mentioned above.

 

You can fit a cam to allow the engine to breathe better at higher rpm, but this will reduce efficiency at lower rpm & cost you torque and economy.

 

A turbo recovers energy that's escaping through the exhaust, which can give you more economy and you can blow  pretty much all the air you want into your engine to make power where you want it.

 

 

...and what Phil says applies to all of the above.

[Mini_Tom94]

I will be keeping the SPi system. Hmm, I guess 80bhp would be a good starting point for me. Insurance is also an issue as I'm still a young driver but I'm planning on adding a turbo or supercharger in the future. I've seen a few stage 3 heads around, would that be a good choice?

[zinzan]

I'm interested in input on this as well.  Could go VTEC swap at some point down the line in my '93, but that's pricey.

 

What if you put like a dozen K&N filters on it? 

[Brad_Raybould]

It wont effect the power but the power to weight ratio will be improved. Reduce weight as much as you can. Remove unnecessary stuff or replace certain panels like boot and bonnet with lighter alternatives like carbon fiber or fiberglass.

 

Heres a perfect video to what you could remove but don't take it too seriously. Mighty Car Mods sometimes go over the top.

 

Edited by Brad_Raybould, 16 August 2013 - 08:48 AM.

[silve1999]

awesome job

[Cooperman]

If it is a daily driver then be aware that more power tends to equal less reliability, especially with a classic car such as a Mini.
Up to around 80 bhp will be OK and the car will still be easy to drive in traffic with no major transmission issues. Beyond that a much hotter cam will be needed which, in turn, means higher revs, a lower final drive ratio, stronger diff unit, higher fuel consumption and more frequent engine re-builds. If you want a car which will easily keep up with modern traffic, a 55-year-old design is not ideal.
Best advice might be to get to 75 to 80 bhp and simply enjoy classic car driving as it used to be in the 60's & 70's.

[mini_man_dan]

100bhp out of the spi is possible, a guy on here named sprocket managed to do it.

 

He lists how he managed to do it in this thread:

http://www.theminifo...626-spi-tuning/

 

My spi is running a modified head, kent 274 cam and stage one kit and is putting out 78bhp, very driveable and reliable just not massively powerful. Would highly recommend this set-up for a daily driver.