Group A Supra race car
- Thread starter john smith
- Start date
Hey guys , sorry about the long time to reply, but Im not very good with computers. Yeah the white whale went really well for us , right up to the point where it holed a piston . The boost was running at 1.4 bar which is where it has run for the past 20 years. But iI think the computer had a heart attack and and over advanced the timing. I had a pretty handy lead and only had to finish the last half a lap. Any way Shit happens. We have just pulled the motor out and getting ready to rebuild it. We are also exploring new management systems and hopefully that will cure the problem. The car is incredibly original and could do with an update in the computer department. We are starting now to have it ready for The MCM in September and this time I dont intend to run 2nd. Regards Smithy
john smith;1796146 said:
The "holed piston" actually reminded me of the international Toyota MA70 Turbo Debut in Touring Car Races. In 1987 ,20 days after the official FIA Homologation, 7M-GTE powered Bastos Toyota Supra driven by Hans Heyer out-qualified the Ford Sierra Cosworths for the 24h SPA but finished the race with holed piston after 59 laps...
Lol ,mutated CT26 running and 1.4 bar would explain why the factory sponsored "Toyota Racing Tom's" Turbocharged MA70 Supras cars were not faster than the private Bemani Supras which were Naturally Aspirated. Unfortunately either engine setup was doomed not to be GroupA competitive.
Anyways good luck with rebuilding or rather reTuning the engine ,I hope that your tuner chooses Sivecs for your ECM ,but I guess he would be a MoTec fan
Don't let the Godzillas win the 2012 MCM !
I am lost of words right now
but really be neat if you post what parts cam out of this motor
I wana see the oil pump
but really be neat if you post what parts cam out of this motor
I wana see the oil pump
Welcome to the forums! WOW. I have drooled over the pictures of your car for some time. Please upload more! What are you going to do with that Turbo-A ECM?:evil2:
Just to give the community and idea as to how fast the Group A MK3 Supras really are ,here is a little comparison of John Smith times at Eastern Creek INTERNATIONAL RACEWAY vs some extreme Time Attack MK4 Supras.
Regulation:
John Smith car back in the days was regulated by FIA to use only Evo Model homologated turbocharger (as described here) and to run minimum weight based on the FIA 1.7 rule 2954.2 x 1.7 = 5022.14 or 1420KG (Migh've been a little different for Australia?). He can comment on the current setup of the car ,but in my experience historic races usually requre the car to be pretty close to the original FIA regulations set by article 255
MK4s that I found are running in the World Time Attack Challenge in Clubsprint or Open Classes , Rules here and here . Basically engine mods including turbocharger are free ,weigh reduction is also almost free (no minimum weight).
2011 Results:
Group A MK3 Supra driven by John Smith - best time on Eastern Creek in competition that I found 1:41.6641 (results here)
Open Class World Time Attack Supra MK4 driven by Matthew Rogers - 1:46.3320 in 2011 race results here
ClubSprint Class World Time Attack Supra MK4 driven by Shane Standley - 1:47.0590 in 2011 race results here
Respect!
Regulation:
John Smith car back in the days was regulated by FIA to use only Evo Model homologated turbocharger (as described here) and to run minimum weight based on the FIA 1.7 rule 2954.2 x 1.7 = 5022.14 or 1420KG (Migh've been a little different for Australia?). He can comment on the current setup of the car ,but in my experience historic races usually requre the car to be pretty close to the original FIA regulations set by article 255
MK4s that I found are running in the World Time Attack Challenge in Clubsprint or Open Classes , Rules here and here . Basically engine mods including turbocharger are free ,weigh reduction is also almost free (no minimum weight).
2011 Results:
Group A MK3 Supra driven by John Smith - best time on Eastern Creek in competition that I found 1:41.6641 (results here)
Open Class World Time Attack Supra MK4 driven by Matthew Rogers - 1:46.3320 in 2011 race results here
ClubSprint Class World Time Attack Supra MK4 driven by Shane Standley - 1:47.0590 in 2011 race results here
Respect!
I only just saw this thread now but i'm glad i've found it. I had heard a sniff that John was campaigning the car again and watched all the TV footage of the Historic meeting at EC in Sept but didnt get to see the Supra , now I know why!
John, I noticed you said you needed a diff ratio that would be suitable for Albert Park, does this mean you will be racing the car on the F1 GP weekend in a support category??? I will be there as a spectator and as a huge motorsport and A70 Supra enthusiast I would love to have a closer look at your car. Id love to pick your brain about suspension set ups from a guy who is trying very hard to set up my own JZA70 for track work with very little knowledge out there about these cars in that regard.
How many weekends per year does the car race?
cheers
Simon
, now I know why!John, I noticed you said you needed a diff ratio that would be suitable for Albert Park, does this mean you will be racing the car on the F1 GP weekend in a support category??? I will be there as a spectator and as a huge motorsport and A70 Supra enthusiast I would love to have a closer look at your car. Id love to pick your brain about suspension set ups from a guy who is trying very hard to set up my own JZA70 for track work with very little knowledge out there about these cars in that regard.
How many weekends per year does the car race?
cheers
Simon
Hi guys, yes you are correct about the weights. The old girl has to weigh over 1400kg as opposed to the Skylines 1300kg . We have done a lot of work on the springs and shocks ,making the car more flexible , and with the help of a couple of guys from this forum, the engine is currently getting rebuilt to the original TRD specs. I am trying to keep it as original as possible. The big improvement in the car has been in the brakes ,the modern pads are light years ahead of what we used back in the day. I can now go really deep into a corner confident that it will actually stop ,where as in the old days the last 10 meters of braking was always quite exciting . We don't expect to have the car out again until mid year, as our objective is to win the MCM in September. Im quite sure that next time we can go a lot faster than we did last year. Regards Smithy
No , the ride height is quite low compared to a road car, but the big wheels and tires dictate how low you can get it The car suffers huge clearance problems.
john smith;1809435 said:
John - first thanks for answering setup questions about the Group A Supras! A few fellow members here (like me) are trying to build circuit race cars using the Supra Chassis and I have 3 very important questions that have puzzled me for many years. All of them are impossible to answer without deep engineering knowledge about the suspension geometry on the cars or years of serious racing experience. I would greatly appreciate if you share some suspension setup knowledge with us.
1. What was the optimum front caster that Toyota suggested or you found in your racing experience is the best for the Supra? I've heard that it was over 10 degrees - is that correct?
2. Have you done any roll center correction on your Group A Race Supra? I see no less than 10 different types of knuckles (uprights) that Toyota homologated ,unfortunately the photos in my FIA homologation papers are kind of blurry and I’m not sure if some of them were actually used for roll center corrections or the correction was actually done on the subFrames like on Sierra RS500 for example?
3.What are the spring rates that you are or have been using? Again in the FIA homologation papers I see no less than 20 different roll bars (some adjustable from the cockpit) ,and the spring rates are closely related to the roll bars choice. I was also told that the maximum spring rate that was available true TTE was 22 KG (f/mm) …
Hi LD ,Im not sure that i can be much help to you as i think your knowledge on Supra is greater than mine. But I can only pass on my experiences. With regard to my car, it arrived from Japan with 10 degrees of caster, 4000l lb springs, shocks that would do justice to a Mack Truck and on the deck. That may have been fast if we were racing on a billiard table, but here in Aus. the circuits are anything but. The caster played havoc with the power steer and put great strain on the hoses etc .I believe they ran that much to induce camber on turn. It was a fad at the time and never worked. We wound it back to abt 5 degrees and all has been well. The same applied to the springs . the car was that stiff that when I drove the car, it would bounce al over the track if it hit a bump. The stiff shocks were there to control the springs. We chucked them all out and started again and ended up with 1500lb fronts and 1000lb rears and backed the shocks off to suit The same applied to the ride height . They had it so low that it scraped its ass every where (this was another Japanese trend back in the day) and there was no compliance. Here was a car with very sophisticated suspension being run like a go kart. We then raised the ride height to a point where the suspension was doing its job and the tires no longer hit the inner guards . The car is now much more forgiving to drive and doesn"t feel nervous. LD, with regard to the roll centre , we have not played around with it, other than raising the ride heights I hope to look at that area soon. We have tried a number of shocks and have used double adjustable alloy Konis but have settled on Bilsteins. I hope that this is some help to you. Regards Smithy
Its amusing to think that TRD japan set their cars up based on fads, I guess it was the 80s after all haha.
John, what sort of subframe mounts does your car use at the front and rear? I assume NOT that terrible floating rubber style of the factory cars...but what you are saying is that the subframes are mounted in their factory orientations? Was your rear subframe strengthened in anyway? (As they are known for cracking with abuse/age). Can't really slam these cars without totally fucking the suspension geometry but I guess big tyres rubs out all possibilities of that anyway.
I would also seriously consider trekking up from Adelaide to EC to watch this car at MCM (along with the other "historics").
John, what sort of subframe mounts does your car use at the front and rear? I assume NOT that terrible floating rubber style of the factory cars...but what you are saying is that the subframes are mounted in their factory orientations? Was your rear subframe strengthened in anyway? (As they are known for cracking with abuse/age). Can't really slam these cars without totally fucking the suspension geometry but I guess big tyres rubs out all possibilities of that anyway.
I would also seriously consider trekking up from Adelaide to EC to watch this car at MCM (along with the other "historics").
Hey spiller ,that photo of your car looks like its at Mallala .Do you compete there? Everything in the car is solid mounted and braced. the chassis is also seam welded.
john smith;1809671 said:
Thanks for the info John! It was quite interesting and helpful at the same time
Lol! It sounds that the Factory Tuners took so much beating from the private Trampio Sierra in JTCC that they lost their minds! That is the only way to explain the 4000lb/in front springs
Unfortunately the Toyota Factory Tuners really could not do much more than trying to keep the car as low as possible when the works Supras in Japan weighed 1420KG and their main competitor - the private Sierras ~1100KG...In a way your conclusion that for the 1400+KG race weight the 1500lb/in front spring are the best choice is not surprising. Coincidentally the only other MA70 Race Supra that is known to me to actively participate in historic races (owned by the Alexandar Strik from Holland ) is setup with front spring rates of 1600 lb/in
I'm very inserted in your AntiRollBar(swayBar) setup ,I would guess FIA homologated TRD 32mm in the front and 25mm in the back?In the past ,I looked into roll center correction and it appears that ~15mm can be gained by modifying the rear sub-frame ,a forum member from Spain found a way to correct over 30mm in the back - once I know more I will share it with you. Front will be very difficult and would require custom knuckles. Luckily enough the changed roll center does not appear to be affecting the Supra MA70 as much as other cars ,this migh've been the reason why Toyota did not homologate any roll center adjuststment parts.