14 replies to this topic

[R32Egor]

HI all,

 

I have a 1996 SPI Cooper (63HP) with the following modifications so far (basically a stage 1) -

 

K&N replacement filter

Maniflow LCB exhaust manifold

RC40 rear double silencer exhaust (retaining the CAT).

All sensors etc redone and I know the engine is running good, ECU was refurbished  (have software etc).

 

My Plan is to basically max out the ECU capabilities with -

 

Stage 3 head 

CAM? (which one?)

Throttle body and variable fuel pressure valve from Classic Mini Japan.

 

All of that is for next winters work (this winter is exterior stuff plus new arches) BUT my question is -

 

I have to change the rocker cover gasket and do tappets so  - Would it be worth putting high lift rockers in now? And if so which ones - Hi heard that 1.3 is enough and 1.5 might be too much?

 

Also if I am in there is there anything else that I could do to help power?

 

Thanks for any advice. 

[bpirie1000]

I would say look to,see how the power goes down. Look at the clutch and fly wheel. Very heavy item.

I would also ask what you use the car for.

Final drive change could give you a better 0-60 number with slower top end or a slower 0-60 but higher top end.

[genpop]

The only thing you tune is the dealer's wallet. Stay with what you have.

[R32Egor]

I appreciate the comments and I will be looking into making the usual suspects lighter at a later date.

This year will be styling changes and new 4pot brakes but as I have to change the rocker cover gasket I am asking if some high lift rockers would be worth it on a stage 1 modified engine?

[sonscar]

How will the ECU know to optimise the timing and fuelling?It primarily uses a lookup table of map Vs rpm and then injects what figure is in the box.There is no knock sensor to optimise ignition.A higher pressure regulator increases pressure everywhere and with better efficiency this may not be correct.Just curious.Steve..

[coopertaz]

someone will know better but found when i had an spi the engine mods were always hampered by the ecu. had 1.5 rockers and same spec as you but no real difference then went for mg metro cam which was a disaster for the ecu and had to revert back. my advice would be if you cannot change out or modify the ecu don't bother with big money on the head and rockers instead go for lightened road spec. clutch and flywheel then FD ratio, 3.44 a popular spec, to make the car more lively. best mod i did on it was a clubman straight cut close ratio gear set, NOT dog box but synchromesh. If you do want to do cam and rockers go for 1.3 with only a mild cam

Edited by coopertaz, 18 December 2024 - 11:47 AM.

[R32Egor]

Mode info 

 

Standard spi cooper FD - 3.2 

And I want a b Road cafe racer so the final drive is fine for me

[viz139]

The low down extra torque of the injection manages the 3.2 and 3.1 final drives very well over carburettors. Where the injection losses out is at the top end where the limitation kicks in. I would retain the 3.2 for better top speed cruising and overtaking.

[brivinci]

The only mod that adds real power is the head. That is where you start. If the motor is out, a cam is an excellent way to get the driving style you like to match the power delivery. I am run the Swiftune SW5-07, and Piper 255 (I think) and am now on a custom cam made by Keith Calver. Each performed a little different. This latest needs to be a little higher in the revs to pick up. The SW5 had nice low down torque. The Piper are really well made and are fully drilled so oil can travel all the way through it and onto each lobe. 

The SPi is limited to about 85hp, but that peak for the ECU. You can throw whatever you want at it, the stock ECU just can't handle more. If you are sticking with stock ECU and still looking to improve, lightness and gearing are the way to that. MED flywheel with road clutch is a lovely bit of kit. The SPi has the best overall gearing for me. It's in the sweet spot. If you don't mind losing a bit of top speed and more revs, a drop in the final drive will give you a nice kick in the boot. 

If you are thinking of lifter, I really don't think it's worth going 1:5s. If they add anything over a set of 1:3, it would be at absolute peak and minimal at that. They over stress things. MEDs 1:3 rockers are really nicely made and top class. 

I would love to see some figures on the fuel pressure and throttle body from Classic Mini Japan. I would be interested what they can actually do with a stock ECU. Ive never been a fan of the trying to "trick" a computer by say, forcing more fuel in that it thinks. Seems like a waste of technology. 

[bogstandard]

You need a ECU that can be mapped to the upgrades otherwise a waste of time with minimal power increase. I found this out the hard way with my MPi. 

[brivinci]

With the stock ECU, you can get around 80bhp with the right mods. If you were to add a programable ECU on to that, I would imagine you could fine tune even more.

I can safely say that the mods I have made to my SPi have significantly improved its drivability and fun factor. Will it snap your neck on launch, no but that added power, at the rev range you want, make for a really fun car.

[sonscar]

Be mindful of the duty cycle of the injectors,they can only supply so much fuel controllably,Steve..

[kopi]

I have an SPI and I think you're on the right track. Just max out whatever the rover mems can give because it is a very good ECU. I've perhaps gone further than most with aftermarket programmable ECUs, hours on rolling roads etc. If I were to be honest, what little extra power was never worth the sacrifice in daily driveability. I'm thinking of reverting to the rover mems, but just as a final stop I just bolted on a holley efi sniper unit. It's basically a "self-learning" ECU and so far it runs great. Verdict is still out on whether it beats the stock rover mems, but that's a story for another day ... 

 

Second the 1.3 rockers

[R32Egor]

Thanks for all the advice - I will do the usual - stage 3 head with 1.3 rockers for the start and then look at the MED fly wheel clutch etc - looks nice.

I will let you know next year if I can afford to fit it all 

[brivinci]

Yes, he 3.44 diff is said to really liven these. I almost did it but ultimately, glad I didn't as I take this car on lots of longer trips. Nice to have the RPMs down a bit. 

The MED flywheel is really nice. Most will tell you that a lightweight flywheel has no place on a road car BUT that really depends on the flywheel. I'm sure someone knows this but the Verto setup looks to be heavier than the non-verto. So, even with a lightened flywheel on an injection car, you might still be heavier than the setup that the Mini was designed with, ie, perfectly roadable;-)

 

When you do pull the motor, that is the time to do the cam. It's not going to add tons but it will add it where it counts and give you a better midrange.