Yummy Late Spec Supercharger Conversion

This is the original article I wrote about Yummy straight after the Supercharger conversion in June 2001.

I bought my MK1 mica blue t-bar in May 2000. I was pretty pleased with the car and it managed to remain trouble free for nearly two weeks! However in true MR2 fashion it started to throw a few wobblies with the coolant! I noticed, much to my alarm that my car had a propensity for blasting it’s coolant out of the back at around 90mph. The only justice to this was that it seemed to like throwing Forlife over Escorts in particular.

Eventually after a numerous visits to the local dealer and a fair few cock-ups the ‘man from Toyota’ (whom I was on a first name basis with by this point) told me that the head was warping when the car was at speed. More than £800 later the car was back on the road again or so I thought (!) it blew Forlife all over Newport Pagnell services! Toyota rushed (well 4hours!) a diesel turbo (never found the turbo) Corrolla to me. I would advise anyone thinking of buying one to go for the optional frontal lobotomy first!

For a relatively trouble free period over the next 8 months (excluding seized calipers, front links, diff carriers and the like) the car ran smoothly and pretty well. I was enjoying it until it suddenly decided it was part of the Red Arrows Display Team! All of a sudden I had clouds of white smoke pouring out of the exhaust and oil all over the place. On inspection it turned out that compression was down on cylinder number three. Of course this meant piston rings or rather a lack of! So what next? I had three options that sprung to mind. First off get rid, though I had already spent around 2K on putting things right with the car including a poly bush kit throughout, new calipers and discs. The second obvious option would be to get another engine and the third was to do something interesting! Whenever something needs replacing on the car I have always upgraded parts wherever possible.

After much debate and thinking of pouring yet more hard earned cash into the bottomless pit, I thought go for it, there’s no point doing things by half! 

After much debate on the IMOC list I was keen on going for a 4A-GE 20valve vvti engine. This is a five valves per cylinder unit with variable valve timing that produces 160Bhp with a Cat! De-restricted i.e. with no cat and a free-flowing exhaust and air filter it ought to put out around 175-180Bhp at a screaming 7500 rpm or so! 

Once I decided that I had the monies it didn’t take long for me to get in touch with Adrian from Fensport (01354-696-968) whom after a lengthy discussion put me off the 20valve as I was concerned about the lack of torque and all the power being in the last 2000rpm. I had also read some articles on the similar Celica 190 criticising the lack of torque and drivability for general driving. With a little persuasion Adrian reckoned the supercharger conversion might be a better option for my needs.

Chasing Vashy in Yummy at Donington Park September 2001

As the MK1 is getting ever rarer these days, sourcing low mileage supercharger engines has proved increasingly difficult so Adrian offered me a late spec supercharger engine from a Corrolla that he happened to have in stock. 

The difference between this engine and the earlier one fitted to standard J-Spec superchargers is that importantly it produces 20Bhp more in standard spec. This is achieved by mainly a higher compression (8.9:1) a smaller supercharger pulley (more boost) narrow ports (increased gas velocity I think) and a few other nice touches like semi-forged pistons better oil cooling and a neat twin coil distributorless ignition system. Of course not one to do things by halves I also went for a ‘Big Pulley Kit’, this means a bigger pulley on the crank which spins the supercharger faster increasing the boost from 8psi or so upto 12-14psi (with my engine spec it is much more like 14 or so). I also bought a Ram Air filter and a Magnex exhaust to help the engine breath more easily and a new clutch. Adrian reckoned the spec for my engine to be good for around 190Bhp or so!

For the fitting the car was duly dropped off to ‘Revving Kevin’ (01905-778-368) in Worcester. Kevin had done this conversion to his own car a few years ago as well as having a highly modified 3S-GTE (turbo) Corrolla! Kevin did a great job and finished the car in two weeks. I used an intercooler from a MK2 Turbo and after a fruitless search for an SC engine lid which was a bit of a nightmare we opted for some modifications to the standard engine lid. 

Original Supercharger engine install done by 'Revvin' Kevin. Note very sharp bends on intercooler piping

Upon picking the car up it was the hottest recorded day in Worcester and the intercoolers lack of air flow was seriously blunting the performance as the ECU was retarding the ignition chronically to protect the engine from detonation. However, as soon as I had had a bit of cruising back up the M5 the full power of the car gave me quite a shock. Julian was following in his shiny red MK3 Roadster and as I put my foot down in 5th at around 70 or so the car just rocketed past 110 in no time! Julian (and every thing else!) gave a good impression of going backwards! 

The sheer torque of the engine is incredible and overtaking 3 or 4 cars at once along give and take A-roads is just so easy! The only problem is that by the time I pull back in, a glance at the speedo puts me well into the ‘wave goodbye to your licence territory’! As the engine is imported from Japan it does still have a speed limiter which is probably just as well, even if it doesn’t cut into to over 130mph! 

I have since had the car round Castle Combe for a day where I found that I was exiting the straight at 120 or so whereas last year I was making around 100mph with a standard car. Of course now I have got this far with the car it has become very much an ongoing project. I have since modified the induction piping with even more shiny silicone and placed the Ram Air filter back in the boot. The next job is to put a further modified engine lid with scoop and intercooler cut on in an effort to increase cooling. I am also looking at water/air intercoolers and water injection. Of course once you start modify you never stop!
Nice pic of Yummy in 2002 on a peak run with the MR2 MK1 Club 15" wheels, koni shock absorbers and Fensport springs 20% uprated, 30mm lower springs have been added in this pic

I would like to thank Julian, Jamie, Toni, Marc, Tony T, , Mik, Adrian, Kevin and everyone else on the IMOC list who gave me invaluable advice and help with getting this conversion done. Interestingly there is only one other MR2 in the country with this specification owned by Adrian at Fensport

About me
MK1a Restoration
Beard Index (mech/tuning)
Spa 2003
Spa  2002
Yummy history
Current Track Car
© Copyright 2003 Lauren