How to Get More HP from a Mini?
Discussion
I am getting ready to purchase a '73 Austin Mini 1275 GT. I would like to know the affordable and efficient ways to get maximum horsepower for the Mini. The Mini will be used for city and highway driving so anywhere between 90-110 HP N/A would be sufficient. My budget is $2000 USD.
Can anyone with experience with tuning 1275 engines give me the stages of increasing horsepower? Moreover, the prices for the items and the location of the supplier. Thanks.
You need to start with the exhaust system, with a bigger bore to ensure good engine breathing. But not too big, I think the 1" systems are as big as you need.
Then you can change the carb needle (hundreds to choose from).
For the power you want, you will be looking at a Stage 3 cylinder head, perhaps a bigger carb (HIF44, Weber), a cam and perhaps an overbore to 1340 / 1380cc. That kind of power will likely need a better gearbox, with central oil pickup. You could go the whole hog and get a straight cut close ratio box, like a Jack Knight.
The cheapest option may be to get a complete unit from someone like MED (www.med-engineering.co.uk).
You can get meaningful horsepower increases with a simple Stage 1 kit (exhaust, intake manifold, filter, carb needle) and these cost around £150.
You will definitely need to check that the suspension and brakes are up to it if you go for the full 100bhp target.
Then you can change the carb needle (hundreds to choose from).
For the power you want, you will be looking at a Stage 3 cylinder head, perhaps a bigger carb (HIF44, Weber), a cam and perhaps an overbore to 1340 / 1380cc. That kind of power will likely need a better gearbox, with central oil pickup. You could go the whole hog and get a straight cut close ratio box, like a Jack Knight.
The cheapest option may be to get a complete unit from someone like MED (www.med-engineering.co.uk).
You can get meaningful horsepower increases with a simple Stage 1 kit (exhaust, intake manifold, filter, carb needle) and these cost around £150.
You will definitely need to check that the suspension and brakes are up to it if you go for the full 100bhp target.
I just the read the article about how to get maximum hp from your mini at minimania.com. I says exactly what you mentioned about the stage 1, 2 and 3 upgrades. I'm limited in cash so anything expensive upgrading the gearbox will be out.
i am looking into the stage 1 mod. In regards to the intake manifold, needle, and air filters, what brand should I go for? And where could I get it from?
i am looking into the stage 1 mod. In regards to the intake manifold, needle, and air filters, what brand should I go for? And where could I get it from?
onLOoker said:
i am looking into the stage 1 mod. In regards to the intake manifold, needle, and air filters, what brand should I go for? And where could I get it from?
Pretty much all the Mini suppliers offer a Stage 1 kit. I have a Maniflow single box exhaust system, on a Cooper Freeflow manifold. You could also look at a LCB (long centre branch) manifold.
The standard intake manifold on a Stage 1 kit is an alloy water heated type. I know that some are better than others, but not sure which suppliers are better.
As far as filters go, you can either fit an improved filter such as a K&N to the existing filter box (and you can drill holes around the filter box to improve airflow) or you can go for the taper type which replace the filter box and sit directly behind the carb. These are a lot noiser than the standard type.
I imagine shipping costs to the US will be high, especially for the exhaust system, if you cannot get the parts locally. A good start would be to call Pete at Somerford Mini (www.somerford-mini.co.uk) and see what he can offer. I don't know whether there are any US-based Mini suppliers...
90-110bhp is possible from a 1293, but more reliable from something bigger say 1380, you will pay for quality and med although good are not cheap!
depends on your budget, if you fancy doing the work yourself, get a copy of the Dave Vizard book, How to tune the A-Series Engine, well worth buying even if you're not. They sell it on Amazon.com
stg1,2,3 is the best budget way to go, but i'd doubt you'd see the kind of hp you're looking for without more serious engine work.
NOTE: if you are considering serious engine work, get hold of an A+ engine they're generally more reliable and better made.
depends on your budget, if you fancy doing the work yourself, get a copy of the Dave Vizard book, How to tune the A-Series Engine, well worth buying even if you're not. They sell it on Amazon.com
stg1,2,3 is the best budget way to go, but i'd doubt you'd see the kind of hp you're looking for without more serious engine work.
NOTE: if you are considering serious engine work, get hold of an A+ engine they're generally more reliable and better made.
With regards to simple tuning at a reasonable price I would concur with fitting a Stage One kit first up.
Get yourself a copy of Miniworld magazine or check out the likes of MiniSport, MiniSpares, MiniSpeed etc. who all supply off the shelf kits. MiniSpeed offer various options on the S1,2 and 3 kits all within your budget.
From personal experience, I can recommend the RC40 as the exhaust of choice (having gone through a Playmini, and a Janspeed on my S Works). It gives the best performance, sounds superb and the extra for an SS one is worth it.
Have fun!
Get yourself a copy of Miniworld magazine or check out the likes of MiniSport, MiniSpares, MiniSpeed etc. who all supply off the shelf kits. MiniSpeed offer various options on the S1,2 and 3 kits all within your budget.
From personal experience, I can recommend the RC40 as the exhaust of choice (having gone through a Playmini, and a Janspeed on my S Works). It gives the best performance, sounds superb and the extra for an SS one is worth it.
Have fun!
I've just finished building a 1972 1275GT Rally Car to post-Historic regs., including a complete power unit build.
Brief engine spec:
286 Kent Megadyne Cam
37/31 mm Valves in a gas-flowed head,
Duplex Timing Gears with offset woodruff keys to set timing at +2 degrees from nominal
10.7 to 1 Comp Ratio
45 DCOE Weber Carb on steel manifold
LCB Exhaust with 3 box Maniflow Big-Bore exhaust (3 boxes to keep within noise limits)
1.5 to 1 Roller-tip rockers,
Aldon 'Red' distributor
Hepolite 21253 pistons at +.060" i.e. 1330 cc
Lightweight steel flywheel.
Lightened con-rods.
K & N Air filter for Weber, plus a few more 'nice bits'.
This gives just over 100 bhp at 6200 rpm
A similar unit which I built recently, but with a single 1.75" SU carb on a Metro inlet manifold gives 88 bhp at 5750 rpm. We're going to fit a better inlet manifold soon to give an extra couple of hp.
For transmission on the rally car we have used a s/c, c/r box with centre oil-pick-up and a 4.1:1 final drive with cross-pin diff. No top speed, but 0-60 in about 7.5 secs.
The key to power is a very accurate build. You must 'deck' the block and set the c.r. properly. I normally charge around £500 for a basic engine build, plus something extra for fitting to the gearbox and setting up. My 1964 Cooper 'S', in legal historic rallying trim gives 100 bhp at 6250 with twin 1.5 SU's and 11.1 to 1 c.r.. However, I use very expensive Karl Schmitt pistons to take the c.r.
Another 1275 engine I built last year was similar to the above, but with twin 1.5" SU's. I don't know the power, but it was clocked at a genuine 110 mph using a GPS system, so it must have had around 95 bhp.
If you build to get around 85-ish bhp you should get away with a standard gearbox, but you must have a centre oil pick-up pipe which costs around £20, and I would recommend a full gearbox re-build to give some reliability.
Don't be misled by pure hp figures, the tractability and drivability of a Mini is very important if you want to use it as a road car. I'd hate to sit in traffic in either of the rally cars mentioned above. For a pure road engine I'd use a Kent 276 or a Piper 270 cam with standard gear ratios. Always build an engine with its use in mind.
If you want this costed, or want more advice, please email me directly and give me your email address.
I hope this helps
Brief engine spec:
286 Kent Megadyne Cam
37/31 mm Valves in a gas-flowed head,
Duplex Timing Gears with offset woodruff keys to set timing at +2 degrees from nominal
10.7 to 1 Comp Ratio
45 DCOE Weber Carb on steel manifold
LCB Exhaust with 3 box Maniflow Big-Bore exhaust (3 boxes to keep within noise limits)
1.5 to 1 Roller-tip rockers,
Aldon 'Red' distributor
Hepolite 21253 pistons at +.060" i.e. 1330 cc
Lightweight steel flywheel.
Lightened con-rods.
K & N Air filter for Weber, plus a few more 'nice bits'.
This gives just over 100 bhp at 6200 rpm
A similar unit which I built recently, but with a single 1.75" SU carb on a Metro inlet manifold gives 88 bhp at 5750 rpm. We're going to fit a better inlet manifold soon to give an extra couple of hp.
For transmission on the rally car we have used a s/c, c/r box with centre oil-pick-up and a 4.1:1 final drive with cross-pin diff. No top speed, but 0-60 in about 7.5 secs.
The key to power is a very accurate build. You must 'deck' the block and set the c.r. properly. I normally charge around £500 for a basic engine build, plus something extra for fitting to the gearbox and setting up. My 1964 Cooper 'S', in legal historic rallying trim gives 100 bhp at 6250 with twin 1.5 SU's and 11.1 to 1 c.r.. However, I use very expensive Karl Schmitt pistons to take the c.r.
Another 1275 engine I built last year was similar to the above, but with twin 1.5" SU's. I don't know the power, but it was clocked at a genuine 110 mph using a GPS system, so it must have had around 95 bhp.
If you build to get around 85-ish bhp you should get away with a standard gearbox, but you must have a centre oil pick-up pipe which costs around £20, and I would recommend a full gearbox re-build to give some reliability.
Don't be misled by pure hp figures, the tractability and drivability of a Mini is very important if you want to use it as a road car. I'd hate to sit in traffic in either of the rally cars mentioned above. For a pure road engine I'd use a Kent 276 or a Piper 270 cam with standard gear ratios. Always build an engine with its use in mind.
If you want this costed, or want more advice, please email me directly and give me your email address.
I hope this helps
I've just finished building a 1972 1275GT Rally Car to post-Historic regs., including a complete power unit build.
Brief engine spec:
286 Kent Megadyne Cam
37/31 mm Valves in a gas-flowed head,
Duplex Timing Gears with offset woodruff keys to set timing at +2 degrees from nominal
10.7 to 1 Comp Ratio
45 DCOE Weber Carb on steel manifold
LCB Exhaust with 3 box Maniflow Big-Bore exhaust (3 boxes to keep within noise limits)
1.5 to 1 Roller-tip rockers,
Aldon 'Red' distributor
Hepolite 21253 pistons at +.060" i.e. 1330 cc
Lightweight steel flywheel.
Lightened con-rods.
K & N Air filter for Weber, plus a few more 'nice bits'.
This gives just over 100 bhp at 6200 rpm
A similar unit which I built recently, but with a single 1.75" SU carb on a Metro inlet manifold gives 88 bhp at 5750 rpm. We're going to fit a better inlet manifold soon to give an extra couple of hp.
For transmission on the rally car we have used a s/c, c/r box with centre oil-pick-up and a 4.1:1 final drive with cross-pin diff. No top speed, but 0-60 in about 7.5 secs.
The key to power is a very accurate build. You must 'deck' the block and set the c.r. properly. I normally charge around £500 for a basic engine build, plus something extra for fitting to the gearbox and setting up. My 1964 Cooper 'S', in legal historic rallying trim gives 100 bhp at 6250 with twin 1.5 SU's and 11.1 to 1 c.r.. However, I use very expensive Karl Schmitt pistons to take the c.r.
Another 1275 engine I built last year was similar to the above, but with twin 1.5" SU's. I don't know the power, but it was clocked at a genuine 110 mph using a GPS system, so it must have had around 95 bhp.
If you build to get around 85-ish bhp you should get away with a standard gearbox, but you must have a centre oil pick-up pipe which costs around £20, and I would recommend a full gearbox re-build to give some reliability.
Don't be misled by pure hp figures, the tractability and drivability of a Mini is very important if you want to use it as a road car. I'd hate to sit in traffic in either of the rally cars mentioned above. For a pure road engine I'd use a Kent 276 or a Piper 270 cam with standard gear ratios. Always build an engine with its use in mind.
If you want this costed, or want more advice, please email me directly and give me your email address.
I hope this helps
Brief engine spec:
286 Kent Megadyne Cam
37/31 mm Valves in a gas-flowed head,
Duplex Timing Gears with offset woodruff keys to set timing at +2 degrees from nominal
10.7 to 1 Comp Ratio
45 DCOE Weber Carb on steel manifold
LCB Exhaust with 3 box Maniflow Big-Bore exhaust (3 boxes to keep within noise limits)
1.5 to 1 Roller-tip rockers,
Aldon 'Red' distributor
Hepolite 21253 pistons at +.060" i.e. 1330 cc
Lightweight steel flywheel.
Lightened con-rods.
K & N Air filter for Weber, plus a few more 'nice bits'.
This gives just over 100 bhp at 6200 rpm
A similar unit which I built recently, but with a single 1.75" SU carb on a Metro inlet manifold gives 88 bhp at 5750 rpm. We're going to fit a better inlet manifold soon to give an extra couple of hp.
For transmission on the rally car we have used a s/c, c/r box with centre oil-pick-up and a 4.1:1 final drive with cross-pin diff. No top speed, but 0-60 in about 7.5 secs.
The key to power is a very accurate build. You must 'deck' the block and set the c.r. properly. I normally charge around £500 for a basic engine build, plus something extra for fitting to the gearbox and setting up. My 1964 Cooper 'S', in legal historic rallying trim gives 100 bhp at 6250 with twin 1.5 SU's and 11.1 to 1 c.r.. However, I use very expensive Karl Schmitt pistons to take the c.r.
Another 1275 engine I built last year was similar to the above, but with twin 1.5" SU's. I don't know the power, but it was clocked at a genuine 110 mph using a GPS system, so it must have had around 95 bhp.
If you build to get around 85-ish bhp you should get away with a standard gearbox, but you must have a centre oil pick-up pipe which costs around £20, and I would recommend a full gearbox re-build to give some reliability.
Don't be misled by pure hp figures, the tractability and drivability of a Mini is very important if you want to use it as a road car. I'd hate to sit in traffic in either of the rally cars mentioned above. For a pure road engine I'd use a Kent 276 or a Piper 270 cam with standard gear ratios. Always build an engine with its use in mind.
If you want this costed, or want more advice, please email me directly and give me your email address.
I hope this helps
I'll just stick with stage 1 mod for now. I want to keep the cost as low as possible. There are other things I would like to do to the car before performance upgrades.
MiniMania.com sells stage 1 kit with air filter, intakes, and exhaust for about 1200 USD. I find that a bit expensive for an exhaust, filter, and intakes. Does anyone know where I could purchase the stage 1 kit for under 500 USD or that's not possible? Additionally, how much hp increase will I expect from the stage 1 upgrade?
d3vine said:
MiniMania.com sells stage 1 kit with air filter, intakes, and exhaust for about 1200 USD
That is outrageous. I just spoke to Somerford Mini (IMHO one of the best Mini spares and restoration companies there is) and they will do the following:
Stage 1 Kit: £165 (USD 265 approx)
Shipping: £65 (USD 105 approx)
Both prices approximate. You can pick and choose the filter type you want and I think you can get a Maniflow exhaust system - which I have and is great.
You can call them on
+44 1249 721421
HTH
Edit: I presume you are in the US? Your profile shows UK...
>> Edited by miniman on Monday 7th July 17:14
I knew MiniMania overcharged it. I'll most likely go with Summerford Mini instead of MiniMania. I doubt the shipping will add much to the price of the stage 1 package.
Do you know the approximate hp increase for the stage 1 upgrade?
I know what is in the stage 1 kit. But what exactly is in a stage 2 and 3 kits? Just in case, I would like to upgrade more hp in the future.
Do Summerford sell rims and brakes too? I would like used rims 10 x 6. All the Mini parts/accessories offered in the states are quite expensive. If the performance parts are cheap over there then I minus well order majority of the accessories/parts from Europe.
d3vine said:
That's great to hear. Do they have a Website?
Yes but it is not very good.
www.somerford-mini.co.uk
Believe me, the shop and staff are a lot better than the website!
Cooperman said:
For a pure road engine I'd use a Kent 276
Some excellent advice, the only bit I'd disagree with is the above. From experience I found that the Kent 276 is a poor compromise. In a 1293 with a standard flywheel and a reasonably well ported head running 10.5:1 CR and an HIF6, the idle quality was really quite poor, despite extensive fiddling of mixtures and igntion timing. My brothers car which was running a 286 scatter cam with otherwise simmilar specs certainly had no worse idle, and made considerably more power. Even the bottom end power was barely superior to the 286. For a road car that is used in traffic a lot, the 266 is hard to beat IMO, but if not, then go for the 286 everytime.
The 286 is my favoutite cam, although I have not used the scatter version. I always use 286's in my rally engines unless asked otherwise.
I recently built an engine for a 1965 Cooper 'S' rally car to be used in longer distance events and used a 276. With a lightweight flywheel, a very good head at 10.4:1, standard ratio rockers (as demanded by the rules) and twin 1.5 SU's, it gave 92 bhp at 5750 rpm. It seemed to have a lot more bottom end than my 1293 rally car which gives 8 bhp more at 6200 rpm with an otherwise similar engine configuration. I think you are right about the 266. I have not used one, but from the timing figs. it should be a great cam for a road engine with fairly high gearing. I certainly wouldn't want to run much higher than a 3.76 diff with a 286 or 3.44 with a 276. Both the rally engines mentioned here have 3.9 diffs with s/c, c/r gearboxes.
The Piper range also seems good, particularly the 270. I have only ever used this once, with excellent results, although I don't have an output figure.
I recently built an engine for a 1965 Cooper 'S' rally car to be used in longer distance events and used a 276. With a lightweight flywheel, a very good head at 10.4:1, standard ratio rockers (as demanded by the rules) and twin 1.5 SU's, it gave 92 bhp at 5750 rpm. It seemed to have a lot more bottom end than my 1293 rally car which gives 8 bhp more at 6200 rpm with an otherwise similar engine configuration. I think you are right about the 266. I have not used one, but from the timing figs. it should be a great cam for a road engine with fairly high gearing. I certainly wouldn't want to run much higher than a 3.76 diff with a 286 or 3.44 with a 276. Both the rally engines mentioned here have 3.9 diffs with s/c, c/r gearboxes.
The Piper range also seems good, particularly the 270. I have only ever used this once, with excellent results, although I don't have an output figure.
d3vine said:
I knew MiniMania overcharged it. I'll most likely go with Summerford Mini instead of MiniMania. I doubt the shipping will add much to the price of the stage 1 package.
Do you know the approximate hp increase for the stage 1 upgrade?
I know what is in the stage 1 kit. But what exactly is in a stage 2 and 3 kits? Just in case, I would like to upgrade more hp in the future.
Do Summerford sell rims and brakes too? I would like used rims 10 x 6. All the Mini parts/accessories offered in the states are quite expensive. If the performance parts are cheap over there then I minus well order majority of the accessories/parts from Europe.
Shop around - most Stage 1 kits should cost you in the region of 150 GBP. The price fluctuation depends largely on the type of exhaust system you pick as it is the main component.
I would also check out:
www.minispares.com
www.minispeed.co.uk
www.minisport.com
All can supply what you're after and have friendly, experienced staff who will talk you through the pro's and con's of each system. They may also be able to suggest some additional small improvements which will give you a much revvier, fun to drive Mini.
They should also be able to supply rims. Get subscribed to MiniWorld Magazine too - all advertise in there.
Contrary to some opinions, mildly tuned Mini's are often the best fun.
Don't forget to think about improved breathing too - a decent air filter will add value.
Oh yeah, expect a bhp increase of 10-20% ish from a Stage 1 but also budget for having the car properly setup on a rolling road to get everything running as efficiently as possible.
Hope this helps.
>> Edited by S Works on Tuesday 8th July 16:06
Hi d3vine,
Where are you in the USA. I have a very good friend who lives just north of LA and he has a 1963 Cooper 'S' 1071 full spec rally car. He will know who the US agents for the Brit. Mini specialists are. I do know that he gets most of his bits fairly locally by mail order - from San Fransisco I think.
If you email me at peterv@dial.pipex.com I'll give you his contact details. There are certainly lots of Mini Maniacs in the States. Every time I go there I seem to get involved in working on them. My wife thinks (knows!) I'm nuts.
Where are you in the USA. I have a very good friend who lives just north of LA and he has a 1963 Cooper 'S' 1071 full spec rally car. He will know who the US agents for the Brit. Mini specialists are. I do know that he gets most of his bits fairly locally by mail order - from San Fransisco I think.
If you email me at peterv@dial.pipex.com I'll give you his contact details. There are certainly lots of Mini Maniacs in the States. Every time I go there I seem to get involved in working on them. My wife thinks (knows!) I'm nuts.
I live in Washington, DC. I was suppose to bid for a car on Ebay. But lost it by couple of hundreds. I can't seem to find a cheap and reliable Mini for sale. The only Minis that I find cheap are out of the USA. But then shipping adds up... I would really like a 1275 Mini as a starter. Although, I have found several MK1 Minis for a cheap price. Many people have told me not to go for MK1 because the engine is too weak. You can't really get much power out of the engine unless swapping out. By then, it won't be affordable anymore.
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