17 replies to this topic

[HUBBA.HUBBA]

fit an SC12, or a Sprintex, the intake is very short and inline.
 
Injection sorts the fuel economy, well when cruising on the motorway.
 
A carb'd charger will only give a max of about 26mpg.

Yep. If I would have my time again I wouldn't have an eaton set up, the intake is far too long.

[fulltiltbrian]

I have a 45 Eaton on my 1310 cooper. I got the car from a guy who'd trashed the car so I set about rebuilding it. I found the engine was in near perfect condition, no wear, nothing broken, so I don't believe its necessary to make major mods to it or the gearbox. Even the diff was fine, though I changed it for one with longer legs, it now has a 2.77. The power is substantial, lots of torque from low revs and a very illegal top speed.

Tuning is difficult and has to be very precise,  fuel consumption is scary and there is an inherent problem with the intake design of the most common kits in that when you shut off the engine, fuel travelling uphill from the carb to the supercharger simply falls back down and flows out of the carb. Its an mot failure. Someone at Jonspeed said they drill a hole in the carb between the venturi and the float bowl. In thought this couldn't possibly work as the necessary vacuum in the venturi would be lost. Sure enough, the car wouldn't run. Now I'm about to fit an American carb - an SS 'Shorty'. 45mm, very low profile, usually seen on big (1800ccs) Harleys. should fit alongside the supercharger, right under the bonnet on a short modified manifold.

If anyone has another solution to the problem I'd love to hear it. 

 

Well, the 'shorty' carb didn't work out, lots of time experimenting on a rolling road led nowhere so back to the HIF 44. There's clearly no solution to the fuel 'run back' problem, so I've simply made a stubby little manifold and fitted the carb straight to the supercharger and cut a hole in the bonnet.. Not the most elegant solution I know, but it works like a charm, and I've made up a welded aluminium 'cowl' to cover it and it doesn't look so bad. I've also swapped the 3mm decompression plate for a 1mm and  there's a big improvement in power. Having top sell the car now, as my housebuild is costing more than expected. Its on eBay, - Rover Mini Cooper Supercharged.

Hope to have another on soon though!

[moke123]

Fulltilt, why did you abandon the shorty carb?  I was planning to go down this route.