11 replies to this topic

[Fastorq]

What’s the best combination of engine capacity + above carbs to get max HP at the wheels and what would that be?

[nicklouse]

rather an odd question. you can get more out of a single HIF44

 

but you go about specing an engine for what you want to use it for and then fit carbs to suit.

 

but the twin 1 1/4s were fitted to the Cooper S cars but more so that the rally cars could use twin carbs as well but larger ones if needed.

[Cooperman]

If set up properly, twin HS2 carbs can give slightly better throttle response than a single HIF44 or HS6 on a 1275 engine.

As 'nick....' says, decide what the car is to be used for, then spec the engine to suit. Anything else is doing it the wrong way round.

Also max bhp at the wheels is not a lot of use on a road car. Torque is what matters. For a 'proper' race or competition car, maximum power has a place, but for road use it is seldom that maximum power is reached.

If fitting twin HS2's then max power and max torque are not what you are seeking. They can work adequately on a 1275 and will be good on a 998/1098.

For best performance you would be best with a 1275 engine re-bored to the next size up from where it is now, with a slightly better cam, an HIF44 (or even an HS6), nice exhaust system, lightened flywheel and a well gas-flowed head with around 10:1 CR.

[carbon]

What’s the best combination of engine capacity + above carbs to get max HP at the wheels and what would that be?

For maximum power go for the largest possible engine capacity.Twin HS2s have been used for 1380s in 'historic hillclimb' spec using 286 or similar cam with well modified head plus all other relevant bits.

 

If you're serious about getting best from twin HS2s then always use a Maniflow or exact equivalent manifold as the BMC item is not great. And if you have to stick with HS2s you can also improve flow through the carbs by various stages of 'vizarding' the carb internals. But some of the more radical carb modifications may disappoint if the car is for road use.

[Cooperman]

A car built to specific competition car regulations will almost always be a big disappointment for normal road driving. It will be harsh, bumpy, noisy and have a low cruising speed due to being geared for acceleration.

For a road car a high-torque flexible and smooth engine is what is needed with a wide ratio helical gearbox and a fairly high FDR. Maximum power is unimportant and peak torque needs to happen ideally at mid-range revs like 3500-ish.

As 'nick....' said earlier, decide what the car is to be used for, then build an engine to suit. If it is for competition, then built to the limits allowed by the regulations. if it is just to enjoy old-type driving on the roads in what is a 60-year-old design, then make it reliable, smooth, flexible and safe.

[Fastorq]

A car built to specific competition car regulations will almost always be a big disappointment for normal road driving. It will be harsh, bumpy, noisy and have a low cruising speed due to being geared for acceleration.
For a road car a high-torque flexible and smooth engine is what is needed with a wide ratio helical gearbox and a fairly high FDR. Maximum power is unimportant and peak torque needs to happen ideally at mid-range revs like 3500-ish.
As 'nick....' said earlier, decide what the car is to be used for, then build an engine to suit. If it is for competition, then built to the limits allowed by the regulations. if it is just to enjoy old-type driving on the roads in what is a 60-year-old design, then make it reliable, smooth, flexible and safe.

Hiya
Ive got a few John Cooper injected minis in mint condition that are not very exciting to drive.
They are ok to look at but lack the sound and gutsy performance of my first Mk1 Cooper S.

[johnR]

I'm going with twin HS2s mostly because I like the look of them! and because the difference between them and a single carb doesn't seem major for a road car.

[DeadSquare]

 

A car built to specific competition car regulations will almost always be a big disappointment for normal road driving. It will be harsh, bumpy, noisy and have a low cruising speed due to being geared for acceleration.
For a road car a high-torque flexible and smooth engine is what is needed with a wide ratio helical gearbox and a fairly high FDR. Maximum power is unimportant and peak torque needs to happen ideally at mid-range revs like 3500-ish.
As 'nick....' said earlier, decide what the car is to be used for, then build an engine to suit. If it is for competition, then built to the limits allowed by the regulations. if it is just to enjoy old-type driving on the roads in what is a 60-year-old design, then make it reliable, smooth, flexible and safe.

Hiya
Ive got a few John Cooper injected minis in mint condition that are not very exciting to drive.
They are ok to look at but lack the sound and gutsy performance of my first Mk1 Cooper S.

 

 

Nice !   When my son was at prep school, a new boy came who said that his Dad collected Ferraris.

 

His Dad also had the world's biggest collection of JCBs                 ,,,,,,,,,,,,,              in his factory.

[Fastorq]

Keep them in a corner away from the Fords
 7367C591-5063-4163-B070-795AF96B497B.jpeg   54.76K   0 downloads

[Fastorq]

I'm going with twin HS2s mostly because I like the look of them! and because the difference between them and a single carb doesn't seem major for a road car.

Looks terrific!
Just needs an original air filter box ... lol.

[johnR]

Trouble with an original air filter box is that it hides the carbs!

[Fastorq]

Satisfaction is knowing not showing ..lol