Supra Dr

iTrader: (14)

Holy 16 year bump.... I'll let it ride since it's a interesting topic.

KahnBB6

iTrader: (5)

I concur with you for the same reason. It's a very interesting topic. Attainable in this chassis if someone wanted to.... depending on the going prices for 3S-GE BEAMS M/T engines are these days (the older 180hp and newer 210hp versions).

And since the sibling Supra MKIV chassis was raced in JGTC long ago not with a 2JZ-GTE but with a boosted 3S-GE.

I once posed an even more left field idea of swapping in the GM LNF 2.0L turbo with a GM factory tune since it will bolt right up to an AR-5 transmission which Aisin derived from their R154 design with modifications.

The 3S is clearly superior to that.


All correct. The main questions for a street SC which is at least 3500lbs would be if going to the 2.0L with a turbo... even a modern twin scroll, and, say the 4.083 that the 2.5L 1JZ-GTE used or even a shorter 4.272 ratio would make for a balanced all around vehicle. Horsepower potential with a turbo kit isn't the issue. Torque and where in the powerband you'd get it are.

An SC300 5-speed is about 300lbs heavier than a Supra MKIV NA 5-speed.

But realistically speaking it would probably be fine. Building an SC this way would be like creating the equivalent of a 1984-1986 Mustang SVO... with some more weight. Very fun cars. And a much better chassis that handles better. For reference those cars ditched the V8 in favor of an evolved 2.3L Pinto iron-block closed deck engine with a T3 turbo and stronger internals. A 300hp DOHC version was ALMOST released for the 1987 model year before Ford killed the project. For years people have boosted those iron block four cylinders up to 400hp, 500hp, even up to 900hp.

I don't know the general limits of the 3S engines offhand but I'd expect similar performance from a vastly superior engine design.

This swap is still done with some MKIV Supras today after all.

Now the transmission choice is where I'm scratching my head. Do people retain the 6-speed manual fromt he high output 3S-GE for higher weight MKIV applications or do they go with a beefier transmission like an R154, V160 (in the past before their rebuild parts became hard to find) or even a Tremec T56 Magnum? Because the SC300/400 chassis is even heavier and that does become an additional stress factor for a driveline that was originally sold in a 3200lb Altezza.

ECU and wiring... as you said I wouldn't be too concerned about that since the harnesses and ECUs are out there and the pinouts are available. Also... standalone aftermarket ECUs.

Overall it's a very cool idea. I'd love to see someone go for it and build a 500hp-ish twin scroll turbo 3S-GE BEAMS SC300. The weight balance would be improved over stock as well. Combine this with a very carefully thought out set of suspension modifications and it might be a very cool road race car.

RudysSC

I LOVE a good light 4-cyl powered chassis. However, these cars are just so damn big I'd have a very hard time justifying putting a 4-pot in. However, if I were going to do so, it's hard to deny the shear greatness of the Honda K-series (I've had several - they're THAT good). I'd stick to putting a Beams in something smaller and lighter. If I were to change anything about my car and wanted to drop some weight - I'd either go back to a 1UZ or swap a nice aluminum block LS engine in.

KahnBB6

iTrader: (5)

Hard to deny this. The SC/Soarer chassis is heavy and really does need help in the torque department. So is the MKIV Supra with similar dimensions but its lightest showroom stock version (non turbo 5-speed) is about 3200lbs which is close to what the Toyota Altezza weighs with a 2JZ-GE installed.

Even the stock JZZ30 Soarer at only 2.5L used six cylinders with a high revving over-square engine design combined with similar short gear ratios that the SC's got due to the weight.

The Honda K-Series is VERY good. So good in fact that some guy recently did a big project swapping a turbocharged example into a Ferrari 308 shell.... to great effect!

And the General Motors LS engines... well... there isn't ever any compromise when swapping one of those into anything that will fit them.

However the Supra MKIV was raced in JGTC with a 3S-GTE or 3S-GE non-BEAMS engine with turbocharging for better weight distribution and the 3S series is legendary in its own right as a high performance high boost capable engine.

....

Stoker kits are also available for it. The JUN Auto 2.2L stroker has a long stroke forged steel crankshaft and forged pistons made by Cosworth.

It's around $5,000 USD but it's very cool for a race engine.

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Swapping a stock 210hp 3S-GE BEAMS M/T engine into an SC300/400 would not be ideal. Far too little torque and not even the same base horsepower as a stock 2JZ-GE will make with far more torque down low.

But if a road race high power 3S-GE BEAMS turbocharged setup were to be envisioned.... that would be a different story I think. It could be easily streetable done the right way but it would be a far more track oriented vehicle at that point. Challenged by weight of course but with that kind of setup and pushing 400-500hp there would be no issues.

Personally I like that kind of high output, turbocharged, low displacement, small cylinder count, high revving engine in any RWD car.

The SC/Soarer does tend to be better matched to the 1JZ-GTE, 2JZ-GTE, 2JZ-GE NA, a 2JZ-GE NA-T conversion and the smooth 1UZ-FE V8's but a turbocharged 3S-GE BEAMS project car is totally possible and has already been proven in the MKIVs.

Not for everyone but I think it would be a lot of fun both to build and to drive, especially for a track car!