Some simple questions (rwhp/clutch) that I can't find answers to

[80083r]

I'm having trouble sorting out among some of the amazing options available for this car.

The hp rating of 232 for the 89 supra turbo is at the exit of the engine (late in the day, I can't remember words what for to talk with) right?

1. What is the rwhp rating in factory condition?

2. Any suggestions on which clutch kit to use for longevity at close to factory hp? I'm on a budget, but I don't want to cheap out... (and I'm in Canada, so sometimes brokerage is a KILLER). there's an Exedy available here... http://www.rockauto.com/catalog/moreinfo.php?pk=2391374 that shipping/brokerage isn't onerous, should I be looking for better though? That's a reasonable budget item for me at $300.

3. Car has 247,000 km on it (154,000 miles) should I replace the flywheel too? Also, what else while I have the transmission out?


I have seen that Exedy is not a terrible brand - it's an OEM replacement rather than upgrade, I guess what I'm asking is what is the bang for buck of going to an upgrade? The car is 99% stock, I use if for sunday drives and I like to accelerate, but not speed/race - so very few launches from 4k rpm.

Thanks for reading - love my car, just still have lots to learn.

 

[hvyman]

If the car is Stock get a stock clutch or equivilant. Flywheel can be machined at a machine shop.

 

[80083r]

so, theoretically, if I work in a machine shop (and I do) I could just machine the flywheel as required? Are all the specs and info I need in the TSRM?

 

[Maple191]

A Flywheel is a giant Rotor, the clutch is made of the same material as brake pads. You have to look at the flywheel face first. If the flywheel is discoloured like black and purple theres no point in cutting, its been too over heated. It also could have hair line cracks. And also check that the Ring gear is ok to reuse other wise that can be replaced on its own. You must also check the runout of the flywheel face. (Check the link at the bottom) But if all is good with the flywheel just cut it a couple of thousands at time. 0.003" and look to see how it comes out in a finnish. Example is the cut equal all around, or did it miss spots. If its missing spots when cutting it needs another pass or two.

http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?S=CL&P=8

 

[Poodles]

I'm having trouble sorting out among some of the amazing options available for this car.

The hp rating of 232 for the 89 supra turbo is at the exit of the engine (late in the day, I can't remember words what for to talk with) right?

1. What is the rwhp rating in factory condition?

2. Any suggestions on which clutch kit to use for longevity at close to factory hp? I'm on a budget, but I don't want to cheap out... (and I'm in Canada, so sometimes brokerage is a KILLER). there's an Exedy available here... http://www.rockauto.com/catalog/moreinfo.php?pk=2391374 that shipping/brokerage isn't onerous, should I be looking for better though? That's a reasonable budget item for me at $300.

3. Car has 247,000 km on it (154,000 miles) should I replace the flywheel too? Also, what else while I have the transmission out?


I have seen that Exedy is not a terrible brand - it's an OEM replacement rather than upgrade, I guess what I'm asking is what is the bang for buck of going to an upgrade? The car is 99% stock, I use if for sunday drives and I like to accelerate, but not speed/race - so very few launches from 4k rpm.

Thanks for reading - love my car, just still have lots to learn.

Clutches are rated by torque, not horsepower. If you're staying stock, use a stock replacement clutch.

so, theoretically, if I work in a machine shop (and I do) I could just machine the flywheel as required? Are all the specs and info I need in the TSRM?

Nope, no specs in the TSRM, they just say to replace it. Face and backstep both have to be ground the same, and the place I've taken mine to has a book with the specs to keep the backstep correct (assume it came with the special machine that cuts the flywheel as it's all they use it for)

A Flywheel is a giant Rotor, the clutch is made of the same material as brake pads. You have to look at the flywheel face first. If the flywheel is discoloured like black and purple theres no point in cutting, its been too over heated. It also could have hair line cracks. And also check that the Ring gear is ok to reuse other wise that can be replaced on its own. You must also check the runout of the flywheel face. (Check the link at the bottom) But if all is good with the flywheel just cut it a couple of thousands at time. 0.003" and look to see how it comes out in a finnish. Example is the cut equal all around, or did it miss spots. If its missing spots when cutting it needs another pass or two.

http://www.cygnusx1.net/Supra/Library/TSRM/MK2/manual.aspx?S=CL&P=8

Discoloration is normal, cracks are not. Also, flywheels are not cut the same way brake rotors are (not cut on a lathe, but ground).

This is what a properly machined flywheel looks like.

 

[80083r]

Ok then, replacement flywheel it is.

No benefit to a "sport/street/track" clutch for longevity, then? I didn't really want a clutch that would break my leg or make normal driving a pita anyway.

At some point in the "I've won the lottery and have so much money I've already bought a monkey" future, I'd think about some mods that might bump
another 50-100hp, which I would guess would still be just fine on a stock type clutch. Mods are things like upgrade freer flowing exhaust, etc - the "simple" stuff.

Point taken on torque vs. HP though - brain fried after long day at work. HP and torque are related so it should give you an idea - anyone ever done a rwhp test on a stock 7mgte?

At this point, I'm not doing the clutch until next spring as that's when I'll have the budget. If it burns out completely, the car gets parked till then.

Cheers, and thanks for the help guys!

 

[hvyman]

232 hp was to the crank when new. So roughly about 190-200 or less depending on wear.

 

[gurley0916]

I did 420 hp 398 tq with my stock clutch so you will be fine with minor upgrades.

 

[GrimJack]

Also, while you have the transmission out, replace the rear main seal. I'd also suggest the clutch master and slave - the slave because you're going to be down there anyway, the master because it always seems to pop right after you replace the slave anyway. I would also check the driveshaft.

Also, I'd buy from Toyota for the master and slave. The Toyota ones are expensive, but they seen to last 20 years. The aftermarket ones are half the price, but they last a couple years at best.

 

[IJ.]

You grind flywheels you don't turn them... :nono:

 

[Nick M]

The car isn't rated for rwhp from Toyota. Even 230-232 is not a hard fast number with variables like mechanical wastegate actuators and slippage of a torque converter.

 

[80083r]

You grind flywheels you don't turn them... :nono:

What's the reason for that? I can turn parts on the lathe at better than +/- .001" total runout... Is it the surface finish?

 

[IJ.]

What's the reason for that? I can turn parts on the lathe at better than +/- .001" total runout... Is it the surface finish?

When you turn a part it's like a groove in a record, grinding gives a crosshatch pattern that won't glaze during the breakin period.

 

[bluepearl]

^^ If the final cut is made at .001, cant the groove be broken up with a rolox disc?

 

[IJ.]

Always had access to a Grinder so have never bothered, it's not an expensive process to get done correctly so why risk the PITA job of having to drop the Trans to do it right for a few $?

 

[gurley0916]

Cost 40 bucks to get my flywheel redone and they had to take .030 off and had to redo the step after i melted my ceramic disc in it.

 

[IJ.]

Cost 40 bucks to get my flywheel redone and they had to take .030 off and had to redo the step after i melted my ceramic disc in it.

Small price to pay as I said

Not to mention if it's heat checked it's NOT going to turn in the lathe without some chatter...
(I worked for a brake/clutch company for a few years as a kid so have a clue about all this)

 

[gurley0916]

Agreed like IJ said with all the work associated with putting a flywheel in get it done right or you will be doing it over. The right finish helps with the break in.

 

[80083r]

Excellent, the process *could* be done on a live tooling lathe (you can stick a grinding head on there) but you're right, if the finish you need comes from grinding, then grinding is the right way to do it.

Where do I find an inexpensive replacement flywheel? Cheapest OEM replacement I've found is $400 plus shipping. I'm planning for worst case once I drop the tranny.