Most power from A-series
Discussion
you'd be looking at the Metro Turbo lump. I'd be reckoning on around 220ish max.
I remember reading about about a Mini which had a turbo added, which on full boost passed the 200bhp point but was pretty much un-controllable even running on 13" wheels. It'll have been in Mini Magazine around 1.5 years ago.
I remember reading about about a Mini which had a turbo added, which on full boost passed the 200bhp point but was pretty much un-controllable even running on 13" wheels. It'll have been in Mini Magazine around 1.5 years ago.
1499 I think is the largest bore/stroke combination but you are at massive risk of bursting through at valve or liner level. Theres also huge modifications with the gearbox that weakens it and allows it to flex under extreme circumstances.
1460 gives not much to play with though more reliability than the 1499. 1430 better again and 1380 I think is regarded as the best trade off.
As for power outputs, not many 1430's are putting out more than 120/130 without forced induction or nitrous.
Vizards Tuning BL's A-Series engine gives the full lowdown...
1460 gives not much to play with though more reliability than the 1499. 1430 better again and 1380 I think is regarded as the best trade off.
As for power outputs, not many 1430's are putting out more than 120/130 without forced induction or nitrous.
Vizards Tuning BL's A-Series engine gives the full lowdown...
I have a collegue who I work with here at Jag who used to race Minis in the sixties (he happens to be emigrating to Australia at the end of the week- Go figure!)
I've confered with him
We say 120-130 Bhp is possible out of a 1293 cc A series.
However, it will be made at 7500 rpm plus and the engine will be virtually undrivable below 3000 rpm.
This is assuming a stock 5 port siamesed cyl head,
286 period cam (0.319 inch lift). You would want to up the compression ratio to around 9.5 -10.5:1 because your effective dynamic compression ratio has dropped with the wild cams installed. Kent do a good "Scatter cam". The Scatter cam is neccassary because being siamesed ported, the cylinder tune slightly differently- and the individual cam lobe re-timing aims to address this.
If you want to throw silly amounts of money at the engine you can use an 8 port head- this will improve breathing immensely. This will allow you to to shorten your duration down from the 286 hot cam by about 10 to 15 degrees lower. You also no longer need a scatter cam. This will go all work well with twin sidedrafts (twin DCOF or Dellorto DHLB) which gives a nice straight run into the port. If you go to fuel injection you can getter even better tuning and torque.
One issue compared to modern engines with the A series is that it is much more knock limited because the spark plug is off to the side.
However for road use I'd reccommend taking the capacity out to 1426- 1480 cc, go for a milder performance cam, say a 270/280 0.293inch/0.315 inch lift cam. You can expect peak power at around 6250-6500 then and have a nice working range of 1500-6500 rpm. Use a CR of 9-10;1. A good tuned low backpressure exhaust and appropriate carbs with re jetting should get you to 80-85 Bhp for fast road use. 1.5 ratio rockers work well in broading up the rev range of the engine too.
Again, Vizards A-series tuning book is really quite good with alot of empirical data (although I question alot of his opinions and his wishy washy theory when trying to justify his OPINIONS!).
You might also want to ask people in the engine section of Pistonheads, as I'm sure they know alot more about the Mini A series then I do!
I've confered with him
We say 120-130 Bhp is possible out of a 1293 cc A series.
However, it will be made at 7500 rpm plus and the engine will be virtually undrivable below 3000 rpm.
This is assuming a stock 5 port siamesed cyl head,
286 period cam (0.319 inch lift). You would want to up the compression ratio to around 9.5 -10.5:1 because your effective dynamic compression ratio has dropped with the wild cams installed. Kent do a good "Scatter cam". The Scatter cam is neccassary because being siamesed ported, the cylinder tune slightly differently- and the individual cam lobe re-timing aims to address this.
If you want to throw silly amounts of money at the engine you can use an 8 port head- this will improve breathing immensely. This will allow you to to shorten your duration down from the 286 hot cam by about 10 to 15 degrees lower. You also no longer need a scatter cam. This will go all work well with twin sidedrafts (twin DCOF or Dellorto DHLB) which gives a nice straight run into the port. If you go to fuel injection you can getter even better tuning and torque.
One issue compared to modern engines with the A series is that it is much more knock limited because the spark plug is off to the side.
However for road use I'd reccommend taking the capacity out to 1426- 1480 cc, go for a milder performance cam, say a 270/280 0.293inch/0.315 inch lift cam. You can expect peak power at around 6250-6500 then and have a nice working range of 1500-6500 rpm. Use a CR of 9-10;1. A good tuned low backpressure exhaust and appropriate carbs with re jetting should get you to 80-85 Bhp for fast road use. 1.5 ratio rockers work well in broading up the rev range of the engine too.
Again, Vizards A-series tuning book is really quite good with alot of empirical data (although I question alot of his opinions and his wishy washy theory when trying to justify his OPINIONS!).
You might also want to ask people in the engine section of Pistonheads, as I'm sure they know alot more about the Mini A series then I do!
Found this site that quite helpfull for turboing minis
www.turbo-mini.com/4598.html
and this one for turboing a Midget
www.turbomidget.connectfree.co.uk/index1.htm
Simon has now done about 60k on his turboed Midget and runs normally around 10 psi for rude boy overtaking.
Im fitting my turbo hopefully sunday, finaly got all the bits I want, including my one off plenum chamber made for me that should fit under the midget bonnet without needing a bonnet buldge
www.turbo-mini.com/4598.html
and this one for turboing a Midget
www.turbomidget.connectfree.co.uk/index1.htm
Simon has now done about 60k on his turboed Midget and runs normally around 10 psi for rude boy overtaking.
Im fitting my turbo hopefully sunday, finaly got all the bits I want, including my one off plenum chamber made for me that should fit under the midget bonnet without needing a bonnet buldge
Thank you - just wondering if the engine can be oushed much further before it's undrivable. So far it does 150 miles to an event the event and the 150mph home. I think from the figs given mine must be close to the limit- better check the spec!
PRETTY PLEASE - can I be moved to Engines Forum????
>> Edited by Stella star on Thursday 29th July 14:11
PRETTY PLEASE - can I be moved to Engines Forum????
>> Edited by Stella star on Thursday 29th July 14:11
i know a guy who hillclimbs a 1380 and has 126bhp. i don't know his spec though except this thing is bloody quick!!
if i can find out what spec he runs, i'll post it up.
i know it's run well all season in this spec and don't think any work has been done to the engine all season.
so if a 1380 can put out a reliable 126bhp, a screaming 14-something will maybe get a strong 130 or, with a lot of work, a peaky 140??
if i can find out what spec he runs, i'll post it up.
i know it's run well all season in this spec and don't think any work has been done to the engine all season.
so if a 1380 can put out a reliable 126bhp, a screaming 14-something will maybe get a strong 130 or, with a lot of work, a peaky 140??
na it's in a mini mayhem. ( i'm not sure if that's a known thing or this guy's homebuild)
it's a really wide body sprint/hillclimb 'proper' (non-clubman) front mini.
the whole car is immaculate. i mean, really grade A so i wouldn't like to think how much money and effort has been put under the bonnet.
it will see off 165bhp fiestas (and almost see off a 210bhp stripped caged etc rover) on sprint tracks and be about 1-1.5 seconds off on hills.
::edited:: it seems to be quite strong low down. i'd guess it's pulling 80% by 3000rpm with everything in by 4000.
>> Edited by tuscan_thunder on Thursday 29th July 14:32
it's a really wide body sprint/hillclimb 'proper' (non-clubman) front mini.
the whole car is immaculate. i mean, really grade A so i wouldn't like to think how much money and effort has been put under the bonnet.
it will see off 165bhp fiestas (and almost see off a 210bhp stripped caged etc rover) on sprint tracks and be about 1-1.5 seconds off on hills.
::edited:: it seems to be quite strong low down. i'd guess it's pulling 80% by 3000rpm with everything in by 4000.
>> Edited by tuscan_thunder on Thursday 29th July 14:32
there are also 16v head conversions - for example the KAD one.
IIRC people have also managed to graft on the head from a BMW (K1100? is that right or is that a boxer twin???) bike...
but:
this is expensive and all a bit academic really.
The head is one of the major structures of an engine, and one of the most influential bits in terms of power, torque and how it gets delivered. If you change from 5 ports to 8, from 8 valves to 16, is it really still an A-series?
IIRC people have also managed to graft on the head from a BMW (K1100? is that right or is that a boxer twin???) bike...
but:
this is expensive and all a bit academic really.
The head is one of the major structures of an engine, and one of the most influential bits in terms of power, torque and how it gets delivered. If you change from 5 ports to 8, from 8 valves to 16, is it really still an A-series?
yeh, i reckon if you make an A-series 16 valve you're as well to change the engine to something like a V-tec Honda.
It depends if you're a purist or not i suppose. I, personally, think the A-series is a key part of a mini BUT, if i was building a mini for absolute maximum power, i would chop the engine.
(and try to build the sweetest powder blue/white roof Cooper S with a Downton A series know to man!)
It depends if you're a purist or not i suppose. I, personally, think the A-series is a key part of a mini BUT, if i was building a mini for absolute maximum power, i would chop the engine.
(and try to build the sweetest powder blue/white roof Cooper S with a Downton A series know to man!)
KAD and JKD do 16v heads.
Arden do an 8 port head with 4 carbs or throttle bodies.
The K1100 fitment was massive trouble apparently.
As for what will fit.
B18C6 Spec R Honda VTEC (Been there, +90mm wings, looks odd)
Suzuki Swift
Hyabusa Turbo (kicking out 350bhp reliably) but the gearbox is an issue.
Rover V8 - Both transverse (
) using a Princess gearbox and Longitudinally using a T5.
They are used as a test bed for some marvellously inventive engineering. This is one of the many reasons I adore them...
Arden do an 8 port head with 4 carbs or throttle bodies.
The K1100 fitment was massive trouble apparently.
As for what will fit.
B18C6 Spec R Honda VTEC (Been there, +90mm wings, looks odd)
Suzuki Swift
Hyabusa Turbo (kicking out 350bhp reliably) but the gearbox is an issue.
Rover V8 - Both transverse (
) using a Princess gearbox and Longitudinally using a T5. They are used as a test bed for some marvellously inventive engineering. This is one of the many reasons I adore them...
I think the max capacity you can get from an A-Series with a 90mm crank and maximum overbore is 1586cc. (74.7m bore by 90mm stroke = 1585cc), but as already described this is not for the faint of wallet....... and has had so much metal removed I wouldn't like to how long it would it would last if used in anger.
Stella star, you haven't told us what you intend to use the engine for ?? Are you limited on capacity by regulation ?? Get sight of Dave Vizzard's book, it's got loads of useful info.
If you are limited to a 1400 class, then 1380 with a standard crank or 1399 with mods would be right. If you're not limited to 1400 then go 1430 using Cooper S/Midget rods on an offset ground non-S crank. With a special crank you're into 1460-1480 teratory with a 73.5mm bore.
The key to A-series power (or any engine really !!)is breathing. The 5-port head can be made to flow pretty well, although race heads have big inlet ports which can cause poor low rpm running. An 8-port or 16 valve head has less compromises than the 5-port, but they do cost considerably more. There are hidden costs with both these conversions, for example an 8-port head requires a cam change as the valves are re-phased, both need special inlet, exhaust manifold and fuel systems.
Next up is cam choice, as with any engine a wild cam will make power at high revs (which means you need a strong bottom end), but low and mid-range torque will suffer. If you are rallying, grassing or X-ing then an ultimate race cam probably isn't what you want.
Fueling also needs consideration. SU's are pretty good and contary to popular belief work well on high power A-series. You could go down the Webber/Del'orto route, and there are fuel injection systems for 5-port, 8-port and 16v heads.
Sorry everyone, got a bit carried away with this !!
Stella star, you haven't told us what you intend to use the engine for ?? Are you limited on capacity by regulation ?? Get sight of Dave Vizzard's book, it's got loads of useful info.
If you are limited to a 1400 class, then 1380 with a standard crank or 1399 with mods would be right. If you're not limited to 1400 then go 1430 using Cooper S/Midget rods on an offset ground non-S crank. With a special crank you're into 1460-1480 teratory with a 73.5mm bore.
The key to A-series power (or any engine really !!)is breathing. The 5-port head can be made to flow pretty well, although race heads have big inlet ports which can cause poor low rpm running. An 8-port or 16 valve head has less compromises than the 5-port, but they do cost considerably more. There are hidden costs with both these conversions, for example an 8-port head requires a cam change as the valves are re-phased, both need special inlet, exhaust manifold and fuel systems.
Next up is cam choice, as with any engine a wild cam will make power at high revs (which means you need a strong bottom end), but low and mid-range torque will suffer. If you are rallying, grassing or X-ing then an ultimate race cam probably isn't what you want.
Fueling also needs consideration. SU's are pretty good and contary to popular belief work well on high power A-series. You could go down the Webber/Del'orto route, and there are fuel injection systems for 5-port, 8-port and 16v heads.
Sorry everyone, got a bit carried away with this !!
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