7 replies to this topic

[dwealds]

Model: Mini Cooper Sport MPI 1275cc Stage 4
Year: 2000
Description of problem (please be as in depth as possible): Hi everyone, this is my first post on here but am after some advice. I have an mpi stage 4 running 91bhp (soon to hopefully be around 100 with new throttle body) so cooling is an issue. Does anyone think that it would be possible to run two mpi radiators in series, one mounted up front like normal and one on the right inner wing where all other rads go? Or any other cooling ideas? I have a ceramic painted manifold already which works fairly well at reducing heat.

Cheers

Dan

[Cooperman]

You shouldn't need an extra rad if your cooling system is 100% efficient. However, an old mod we used to do on rally cars was to take the matrix out of a heater box and mount that in the system to increase the total amount of coolant. then run with a 50% anti-freeze mix, a cool thermostat and, if it's thermostatically operated, a manual switch for the electric fan. The problem with powerful engines is that once they do get hot it's difficult to cool them down.
My 1964 Cooper 'S' rally car runs about 117 bhp with very low gearing. I just have the standard Cooper 'S' rad, a 6-blade export metal fan, a Kenlow fan under the LH front wing and a thermostat blanking sleeve. With that it's fine and I don't need the electric fan very often. My cooling is also restricted by my full-length sump guard and my 2 off Cibie Super Oscar spot lights.
On hot days, if you have spot lights, remove them. You don't need them in the Summer after all anmd in winter or at night cooling is not normally an issue.

Edited by Cooperman, 14 August 2009 - 10:14 PM.

[dwealds]

Thanks for the suggestion, I have heard of people doing that. Are matrixs prone to leaking and where would you place it?

Cheers

[Cooperman]

The heater matrix is stronger than a basic radiator as it' inside the car (normally) and any leak would be a safety-critical issue.
I don't know where you could mount one on a late car with a front radiator, but maybe you could cut out a part of the grill and mount it there with a piece of pierced aluminium sheeting to protect it.
Personally I don't think you'll need it. For a 100 bhp engine you do really need a 13-row oil cooler and that will really help with the overall cooling.
I built a 1330 cc engine for an MPI a couple of years ago to give about 90+ bhp and he ran it with no oil cooler (I did advise him to fit one). He seized a valve when the oil temp got too high on a motorway as it had manganese-bronze valve guides which do tend to 'close-up' a bit if the engine gets a bit hot when the guides and valves are new, even if a new reamer is used when the head is being built. My point is that it was the oil which overheated. He had 4 spotlights on as well, which didn't help.
If I were you I would fit an oil cooler, make sure your cooling system is 'spot-on', add 50% anti-freeze and a 74 deg thermostat and see how it goes temp-wise. It would be wise to fit a capilliary-type temp gauge as the electric ones fitted as standard are not at all accurate. An oil temp gauge can also be useful.

[dwealds]

Thanks for the advice. Looking at the oil temp gauge i have in the car already the oil hangs around the 85 degree mark so i dont really want to cool that anymore. When i get the system back together i will be running on Evans NPG+ to see if that helps as its a non-waterbased coolant and apparently reduces the chance of detonation etc. (they have a huge write up on it at www.racestuff.co.uk). I will definitely look into the heater matrix though as that might be a bit better than a whole extra rad.

[jayare]

There are quite a few of the Vauxhall engined cars running Mpi front mounted rads and some of them are well over 100bhp - I don't think you'll need to add anything more,

JR

[bmcecosse]

And fit the smaller (early type) water pump pulley - the 6 blade fan is well worth having.

[dwealds]

Alright that sounds good to me, cheers everyone