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Discussion Starter · #1,301 ·
Thanks for the good thoughts. The problem has existed for 20 years so it's finally time to get it fixed.

I tried ST43 rear pads for one race - they made the car almost undriveable under hard braking because they would be cool at the beginning of braking zone then heat up just in time for trail-braking into a corner. The result was a series of spins at Road Atlanta. I've used Wagner ceramic with good results (and 1/8th the cost of race pads). I just received a new alternative today; R4-s Porterfield compound - a high performance street pad that should last longer.
 

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I see this was on the rear, I've never tried them on the rear but have thought about it. I've been using Stop Tech "street performance" pads when Rock auto had them and their "sport" the last two races in the rear and get 2-3 races out of them depending on the track and who's driving.
 

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Discussion Starter · #1,303 ·
While I'm recovering from surgery, GB2 is at DIY Autotune as they diagnose a software issue with the MS3 ECU. For some reason the engine runs fine in "wasted spark" configuration but won't run at all in "sequential" mode. The tuner seems to be figuring things out and found some more power with VTC and fuel control. A high rpm miss is now gone and the engine would probably continue to increase power past 8k rpm, but I set the rev limit at 7500 for endurance racing. A bonus is that it will now use less fuel while making all this power.

 

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Happy to hear the update on your recovery....!!
I have to go back through your thread, I'm thinking of going MS or some kind of stand alone to try to squeeze as much as I can out of my 6m.
had a little set back this past weekend at New Hampshire Lemons, got to 4th on saturday, changed an inner tie rod saturday night, realigned the car with a teammates paco hub stands, car turned in so much better and ran in 4th all day sunday, and with 2.5 hours to go the clutch went on me, I sent the last driver out and told him to keep it in 3rd and baby it on the front straight, and he was doing well and then out of habit tried to shift to 4th and then couldn't rev match to get it back into 3rd and chewed up the trans. (cue sad trombone)
 

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Discussion Starter · #1,305 ·
Sorry to hear about your troubles, Dave. Running 4th both days is a good sign that the car is in a good place. I installed a Centerforce clutch on my 6M and never had an issue. These W58 transmissions are getting rare and expensive. I need to find someone who rebuilds them.

Below is my dyno graph for the 6M running on an MS3 ECU. 165hp/175tq on a Dynapack hub dyno which is known to read 10% lower than local rollers (Dynojet, Mustang). On a roller it would be 180/190. The problem is that it really sucks fuel making that power.

 

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Sorry to hear about your troubles, Dave. Running 4th both days is a good sign that the car is in a good place. I installed a Centerforce clutch on my 6M and never had an issue. These W58 transmissions are getting rare and expensive. I need to find someone who rebuilds them.

Below is my dyno graph for the 6M running on an MS3 ECU. 165hp/175tq on a Dynapack hub dyno which is known to read 10% lower than local rollers (Dynojet, Mustang). On a roller it would be 180/190. The problem is that it really sucks fuel making that power.

Yes they are getting tough to find, I have a guy in CT that has done tons of W58's, he modifies them for use in British cars. He rebuilt mine and I will be taking it back to him. he ships all the time.
http://quantumechanics.com/
John was an old school road racer himself, super nice guy.
 

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I'm sure you could always use Marlin Crawler or Driftmotion for W58 rebuilds if you want to ship them out west.
 

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Discussion Starter · #1,309 ·
Ben at DIY found a problem in the software for a cam signal decoder and also an issue with the firing order of the plugs in sequential mode. Now the tune has one ignition table and the engine runs perfectly without wasted spark. Theoretically this will increase the life of the COP since they fire half as much.

After reading about NA K24 builds I also asked if Ben would try tuning with an AFR around 13, and he found some additional HP at higher rpm. The engine seems happy at that AFR but we kept the full-throttle enricher in place for peace of mind. This tune should increase fuel efficiency about 4-5% (5-7 minutes of range for a full tank at race pace).

Final tune added 13hp (3hp more than the previous graph) from 6000-7500rpm using less fuel.



After initial tuning at 13:1 a friend called to ask if I ever had the injectors cleaned. With only one O2 sensor at the collector of 4 header pipes you only get an average of all cylinders. With the move to a leaner tune I wanted to make sure that all cylinders were running the same. I pulled the injectors and had them cleaned - it turned out to be cheap insurance as Ben had to pull another 4% of fuel across the table. One or more injectors was definitely creating a problem that probably would have fried a cylinder.
 

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Discussion Starter · #1,310 ·
It feels great to be back in the garage now that my achilles tendon is functional. I designed and built a new aero package for the front end that includes:
1. Closing off the bottom of the OE air dam
2. Adding quick release mounts for a wood splitter

I also cut another set of front struts but could not find any Bilstein inserts (they are either discontinued or on backorder). As a temporary solution I installed a set of SW20 KYB Excel inserts with my 650# springs. I have no idea how long they'll last.

After a quick spin around the neighborhood I'm ready for a test day Saturday at Barber Motorsports Park.

 

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Discussion Starter · #1,312 ·
The left one creates a small "ram air" effect for an airbox so that will stay open. I'll close the right one.
 
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