mk1.5 gearbox questions...

[jayray]

I have always been too lazy to have a good look at all the ratios in different boxes, I just knew I'd pop in an E153 when I do a mk1.5. However, with the S54, you said you'd want to go lower on second gear without changing third, but on my car (gen1 jdm NA) I find that second and third feel a long way apart (no numerical proof, just feels that way) much larger gaps than any other change.
Personally I'd go higher second gear, maybe leave first where it is, and bring them all down a bit with shorter final drive, although for 350bhp that would be a very short box overall.
What top speed would you be aiming for and would it geared specifically for racing and just live with very high cruising revs on the road, or compromise?


On a slightly different tack, have you thought about any of the V6 motors, 1MZ would be about the same weight or less than a full 3sgte setup with intercooling etc. And if you could get new heads machined up, internals designed for high revs, could it be made into a race capable engine, does anyone know?

Or the 2gr-fe, 270 bhp standard, expensive but Paul is currently working on making it fit into a mk2, so should also be able to be shoehorned into the AW? :pray:

[Jim-SR]

compared to standard rev limit on 3sgte i think you ll need stiffer valve springs bucketless shims and if your wanting peak power at those revs possible a different to standard turbo too going to get expensive,

was already planning on Carrillo forged H-beam rods, o/s forged low comp pistons, heavily worked crankshaft, bored cylinders, line bored mains and cam carriers, heavily worked cylinder head, complete aftermarket valvetrain (cams, o/s valves, underbucket followers, high rate dual valve springs, titanium hardware wherever possible, etc), dry sump, etc. as i said, its nothing more than is required to rev a 4A-GE to 10,800rpm, and i already had the parts to do that, aside from TRD cranks, i had enough parts to build 2 engines! having sold most of the parts ive raised enough cash to do it again on a different engine. i was going to spend the cash on a brand new 2ZZ-GE plus some additional tuning parts, but 3S engines are much cheaper so i can go all out on a 3S-GTE for about the same money and making 50% more power.

as for the turbo, that will have to be changed as per my plans anyway, and im going to be defying convention on my turbo setup anyway with an idea ive wanted to try out for years.

ive given it proper consideration, im not just some kid who thinks revving to 9000rpm is as simple as having a chip fitted to override the rev limiter and winding the turbo boost up!

[Jim-SR]

Have you had a look at the ratios that are in the E51? Wondering if they would be shorter than those in the E153, just because they were mated to less powerful engines, and used in AW's and Corollas as opposed to sw20's and gt4's.
As they are E-series as well, would final drives and gears be compatible?

Here's a whole lot of ratios:
http://mr2oc.com/showthread.php?t=29...gze+gear+ratio

This is the one I was looking for, took ages to find, may or may not be any use:
http://mr2oc.com/showthread.php?t=23...eration+SC+20V


I would guess S54 would be strong enough if you're not launching too often (although once a race will add up) and power is coming on smoothly. As Paul has said, its handling V6's up to near 300 bhp, and with a lot of torque.
Having said that, i don't really know what kills boxes, whether its torque, simple high power or sudden jumps in power or torque.

E51 or E58 gearbox could work ok, not as well as the S54 from my calculations. plus im sure there would be more hassle in making one of those fit, or swapping gear clusters into a E153 casing, if thats even possible. i think of all the options, the S54 is the best out of the box. it is only really 1st to 2nd gear where it could be majorly improved

so far as V6 engines go, ive given it consideration. the 3VZ-FE is too heavy, but is the simple swap. the 1MZ-FE is lighter but is a more complex swap. if i have one specific weakness in the area of an engine swap it is with the electronics, so id rather play to my strengths and go with a simple option unless a more complex one offers a huge benefit. and i just dont see the benefit from the V6 over the 3S-GTE. its got less power, lower down the rev range, but a load of torque. but for what i want to use it for, low end torque is of less importance, i want outright peak horsepower. another major factor is displacement - the car isnt being built as a race car, im not building to a set of regulations, but i am considering the regulations for many different race series during the build, and am building the car so that if in future i want to race it, the option is left open. having a 3 litre car is going to put me in a ridiculous category under displacement classifications, up against cars that would be much faster. keeping displacement at 2 litres is beneficial in that regard, the fastest cars in the same class would be the likes of Evo's and Impreza's and il eat those for breakfast (even if theyve got 600bhp). 98% of 4WD owners cant drive 4WD how its supposed to be driven, and the 2% who can are still in cars that dont like cornering.

[OlberJ]

So what are you going to do to the S54 to give 170 top?

Custom final drive? Extended 5th?

Or is the 9000rpm rev limit putting you up there?

[Jim-SR]

9000rpm rev limit pretty much does the job! no idea if it will actually be able to hit 170 or not. calculations suggest it should just about be able to, but it will probably take forever to get there. realistically it wont likely see more than 140-145mph on any circuit in the UK