What are my options to increase BHP?
Discussion
I have been considering my options to increase the speed/power of the mini. As some of you may know I am currently running an MG Metro 1293 engine with 3:4 diff, electronic ignition and nothing too out of the ordinary.
Initially I thought about my options with regards to mappable ignition such as the Autosport labs Megajolt, however I'm not sure I will see a considerable difference in power as after all thats what I'm after!
Is forced induction really the way to go? I'm quite excited about the Mirage turbo manifolds as they do not require a bulkhead box to be fitted, however I don't know if I can justify £300 for an inlet and exhaust manifold and then £600+ in parts for and a turbo!
Supercharging has also been an option I have been looking at. Vmax Scart, 60% power increase, however the Eaton 45's aren't really designed for this specific purpose (fuel/air to go through) which upsets the bearings as I think I read somewhere on here.
I have a spare 90's cooper cylinder head that would benefit from gas flowing and opening up the ports, but I assume that wouldn't see a noticeable difference.
What do you suggest? 120bhp, Yes please!
Tom
Initially I thought about my options with regards to mappable ignition such as the Autosport labs Megajolt, however I'm not sure I will see a considerable difference in power as after all thats what I'm after!
Is forced induction really the way to go? I'm quite excited about the Mirage turbo manifolds as they do not require a bulkhead box to be fitted, however I don't know if I can justify £300 for an inlet and exhaust manifold and then £600+ in parts for and a turbo!
Supercharging has also been an option I have been looking at. Vmax Scart, 60% power increase, however the Eaton 45's aren't really designed for this specific purpose (fuel/air to go through) which upsets the bearings as I think I read somewhere on here.
I have a spare 90's cooper cylinder head that would benefit from gas flowing and opening up the ports, but I assume that wouldn't see a noticeable difference.
What do you suggest? 120bhp, Yes please!
Tom
Budget is everything. If a relaible 120bhp is required - Go the BMW K-Bike head route. And buy a strong gearbox (4 sync straight-cut).
Limit for a tractable road engine (1293) on 5-ports is around 90 bhp (maybe 95 BHP with mapped ignition to tame a really wild cam profile-286/SW10 etc).
Tom - Get the spare head modified by someone reputable and increase the CR a bit - 10.5 should be seen as a limit to avoid problems with variable fuel quality. Bolt on some 1.5 ratio rockers, it'll gift lift without duration, car will remain drivable and fuel economy won't be to adversely affected. If that isn't enough - engine out and cam change.
I had 64bhp at the driving wheels whilst maintaining the stock cam on a 1275 road engine - it can be done. THe engine gave decent fuel mileage and 110K worth of service. That's roughly 80-85 flywheel BHP and it is more than enough to make a Mini move with real style
Limit for a tractable road engine (1293) on 5-ports is around 90 bhp (maybe 95 BHP with mapped ignition to tame a really wild cam profile-286/SW10 etc).
Tom - Get the spare head modified by someone reputable and increase the CR a bit - 10.5 should be seen as a limit to avoid problems with variable fuel quality. Bolt on some 1.5 ratio rockers, it'll gift lift without duration, car will remain drivable and fuel economy won't be to adversely affected. If that isn't enough - engine out and cam change.
I had 64bhp at the driving wheels whilst maintaining the stock cam on a 1275 road engine - it can be done. THe engine gave decent fuel mileage and 110K worth of service. That's roughly 80-85 flywheel BHP and it is more than enough to make a Mini move with real style
I love original Mini's. My cousin had a lovely 1275GT. It really tempted me to look at getting one as a daily.
When I was planning/looking I decided I'd have gone 1380cc with a hugeish cam, ported heads and all the induction/exhaust bolt ons. Not the cheapest, but I think circa 120hp was the quoted figures.
For me I'd have wanted to have kept it n/a for the response and kept it A Series for the noise.
That said, forced induction is the way for bigger power. But you'll still need to sort out the engine and gearbox. Forged internals and probably a good aftermarket EFI setup.
That said, if big power was really what I was after, I think I'd probably look at an engine swap. Can't you get a kit or parts to fit a K-Series these days? Either that or look at a bike engine conversion.
When I was planning/looking I decided I'd have gone 1380cc with a hugeish cam, ported heads and all the induction/exhaust bolt ons. Not the cheapest, but I think circa 120hp was the quoted figures.
For me I'd have wanted to have kept it n/a for the response and kept it A Series for the noise.
That said, forced induction is the way for bigger power. But you'll still need to sort out the engine and gearbox. Forged internals and probably a good aftermarket EFI setup.
That said, if big power was really what I was after, I think I'd probably look at an engine swap. Can't you get a kit or parts to fit a K-Series these days? Either that or look at a bike engine conversion.
Mini_Lund said:
Tell me more! I'm assuming it isn't a bolt on job? Has anyone on here done this?
Thanks
http://www.specialist-components.co.uk/ - fill yer boots - see the Youtube footage at the bottom and if you are still left doubting, search for BMW K-head Mini's on Youtube. The beauty is that it all fits under a standard round nose bonnet profile. 120 horses is a going in point on a standard head casting and standard bike cams.Thanks
Ideally I'd love to keep the 1293 having rebuilt the engine, I'm now swaying more towards the turbo route purely because parts are readily available and not so much bespoke/specialist. Its something I'm going to have to have a long think about. I currently only have 112ft lb's of torque
Everything you need to know about adding a turbo is here
http://www.turbominis.co.uk/forums/index.php
http://www.turbominis.co.uk/forums/index.php
FWDRacer said:
Bolt on some 1.5 ratio rockers, it'll gift lift without duration, car will remain drivable and fuel economy won't be to adversely affected.
Hi Gareth,I have been thinking about getting a set for a while now, but was unsure of peoples experiences of them. Its not going to shoot a valve through the piston is it?
Edit: > I'm waiting for Rich to come along and tell me to get a Volvo
Edited by Mini_Lund on Tuesday 24th May 13:58
Tom - My experiences were 100% positive - Set I had were bushed on rocker shaft (needle rollers are an overkill for a road engine), with roller tips and the head used uprated springs, but not mega poundage types, and the whole assembly head/rocker set did 80K miles including regular 6K+ rpm usage. Set I got came from Minispares.
FWDRacer said:
Tom - My experiences were 100% positive - Set I had were bushed on rocker shaft (needle rollers are an overkill for a road engine), with roller tips and the head used uprated springs, but not mega poundage types, and the whole assembly head/rocker set did 80K miles including regular 6K+ rpm usage. Set I got came from Minispares.
I have a set of double valve springs, would they be required if I fitted the 1:5 rokers? - If so its a head off job and I really cant be bothered I've always fancied a Shorrock Super-Charger on a Mini. I did some work on an A-H Sprite Mk.1 which had a Shorrock blower and it was so easy to set up. Google 'Shorrock' and see what i mean.
In the 60's it was popular to fit a 'blower' on the 850 and it sure worked well.
You don't have the high-temperature issues with a supercharger as it runs cold.
In the 60's it was popular to fit a 'blower' on the 850 and it sure worked well.
You don't have the high-temperature issues with a supercharger as it runs cold.
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