92 replies to this topic

[roofless]

Swear that guys on here.. Works for moss?

he is, and I just sold him some stickers for it car is known as the oz cooper special I believe

[mini.cooper998]

he isnt running an m45 though as i can remember

was in mini world / mag a while back

amazing build quality and eye for detail he has

[Prawn]

haha, yea, and it's not 200bhp either!

[steble]

thats where i plan to be putting my carb if i stay with a suck trough set up, def get more power that way imo and it will help stop carb ice me thinks.

as for the convo on a 1380 being better than a supercharged engine i really don't agree just look at the value for money

to build a decent 1380 your looking at what 3-4000 and as someone has already said it will be lumpy at idle no good around town etc etc and i've seen many many 3-4000 quid engines that haven't even got over 100 bhp if i spent that much money and only got 80-100bhp i would cry a lot

where as to get 123bhp from a standard 1275 with a suck through supercharger it will cost you 1600-1800 as thats what i'm running and all i have is a modified head and the charger i will be building a better engine to go with the charger in the future but at the moment i'm happy with that.

and now i worked out the problem with my mini it drives perfectly as a everyday car

[Sam Walters]

In this 1600-1800, have you thought about cooling or the gearbox?

In reply to the original question, 200BHP supercharged is achievable on an a-series engine. But certainly wouldn't be an easy task.

Now in terms of cam choice, a lot of the high end cams are frowned upon because of their overlap. Overlap is when the inlet lobe of the cam is opening a valve as well as the exhaust lobe opening a valve. My theory on why some cams are lumpy at idle comes from this too, maybe right, maybe wrong.

Science time perhaps? Well, as the inlet and exhaust are both open at the same time. Maybe due to the exhaust gasses not having enough velocity to exit through the valve and out the port causes, some of the gasses to remain in the chamber, or even return from beyond the valve. under vacuum. Therefore causing the mixture to become contaminated. N/A engine.

The theory i presume on a forced induction engine is that due to the velocity your forcing the air though. You would be blowing the mixture straight though the inlet valve, and back out through the exhaust valve.

The whole engine really needs to be thought about. In terms of bore to stroke ratio, as well as rod length to stroke ratio.

However. A well build 1293-130 with a reasonable head and a gt17 turbo on mapped ignition, will get you very close to what you want.

Better fuel economy then a suck through super charger, more power.

Id go:
Reasonable head. Maybe 8.5:1 compression ratio.
KC274 Cam.
Gt17 turbo
Mapped ignition
Good condition gearbox with a cross pin diff.

Circa 10 psi i believe would net you 140bhp. With boost coming in progressively between 2200 revs and 3000 revs.

In terms of cams Kent cams 266, Avonbar phase 2 and the Kent Cams 274 have proven to be good road going contenders.

Also if you built the engine with good quality pistons, and a good straight cut box + cross pin diff. Wind the boost up to around 20psi and you've got a 170bhp + engine.

Edited by Sam Walters, 23 March 2010 - 09:22 PM.

[mini.cooper998]

in terms of the best cam for a forced induction engine what is best and what is best at reasonable cost. also would a scatter cam be any good say a 286 scatter cam

[Wil_h]

The requirements of a turbo and a supercharged engine differ, you can run much wilder cams on an SC compared to a turbo. But in all cases a scatter cam would be pointless.

[Sam Walters]

I think in both cases, the KC274 would be a good cam.

[steble]

1600-1800 includes an uprated 2 core radiator and my car has yet to get over the halfway mark on the temp gauge even on track

gearbox will obviously pack up at some point hence me building a better engine i will also be building a better gearbox, at the moment though until i have the money it is staying as it is and am yet to come across any problems even the standard clutch is currently holding out.

[jay30]

I have a 1430 stage 4 that should be kicking out around 120bhp once setup correctly but I'm also looking at supercharging. My reason for charging is for the linear push through the whole rev range and the general drivability. In the hope of getting to around the 160+ BHP am I looking in the right place?

What are the alternatives to the Bini Eaton charger? How much would an equivalent Turbo set-up be and how drivable?

[Wil_h]

Starting from scratch a turbo installation is going to cost much the same as an SC.

There is not as much choice with superchargers as there is for turbos, the SC12 has been used with success.

Modern turbocharged engines can have full boost at 2000rpm or less and still make good power.

[Gr4h4m]

IMO its simple:

200 BHP - Turbo charge it.


Supercharge - it if you want modest gains and use the car for fun and running about. Most supercharge kits are box ready to take your current engine to the new configuration however, there are always extra's like mapped ignition for Carb cars, etc.

Now both superchargers and turbo chargers are bolt on kits, but you will need a bit more research if you want to go turbo charged, to get all the bits you need and size the turbo charger, IC, IC mounting location, IC piping, bulk head box or mirage manifolds, convert your carb to accept boost, and choose the Plenum chamber, high output pump and return to T line, regulator, dump valve, waste gate. etc.. Wil could give a better list. Thinking about it I might be a good idea to get a list of parts, suppliers to go with the how to post.

[CH007]

OK now you have really got me wondering

I am indecisive at best of times and had finally settled on SC for the final build. The car is at rip down full rebuild stage so nothing is set in stone yet. i think i will be welding in a bulkhead box now

I am happy to build manifolds etc myself but the only thing I am not keen on is a box of tricks for timing or can that be done with standard units rather than ECU?

[Turbo Nick]

i used to be the same chap, hated the idea of having a box of tricks and letting something non mechanical control my spark.

Since fitting my jolt though it's opened my eyes, definately one of the best things i've done. Datalogging with an AFR input is invaluable, exact spark timing when running 20psi on a high CR is also invaluable amongst other things.

Seriously its not that difficult to get your head around, there's plenty of people about with one fitted and makes understanding easier if you can talk to someone about while looking at one working. If you're anywhere near wolves i'd be happy to show you how it works and helps.

[Sammy D]

Right, well...

My engine is a 1293 with a MiniSpeed blower kit. With a 276 cam I only saw 140hp, I've just got a brand new billet cam from Kent Cams which they have pretty much designed for me with more lift than a 286 but with much much less overlap as with my 276 all that boost was being blown out the exhaust. I've also got a bigger pulley to go on the crank coupled with a 15% smaller pulley on the top. MiniSpeed have had running a Supercharged 1380 running 1 bar of boost with no thermal efficiency problems... So Alex told me.

My engine should be all rebuilt again in a few weeks, so with the extra boost and much better cam, let's see what happens.