1300 Kg Track SUPRA project

te72

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jajajaja yes! i know what you say.... another owner of a Supra whish started a track Supra years ago had a bad influence in mine !!

thanks!
I know how that goes, I blame my buddies Andrew and Clint for getting me into these cars in the first place. My project is a fine line between street car and track car, so it is a LOT heavier than yours, but it makes a great road trip car to get to far away tracks, so it works out. It's difficult though, with a dual purpose car. Track only, sacrifices of comfort are easy to make as it will make the car faster... you understand I'm sure.

What am I looking at in the passenger side foot well? Looks like a hydraulic reservoir of some sort. Remote brake booster?
 

josbeat

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I know how that goes, I blame my buddies Andrew and Clint for getting me into these cars in the first place. My project is a fine line between street car and track car, so it is a LOT heavier than yours, but it makes a great road trip car to get to far away tracks, so it works out. It's difficult though, with a dual purpose car. Track only, sacrifices of comfort are easy to make as it will make the car faster... you understand I'm sure.

What am I looking at in the passenger side foot well? Looks like a hydraulic reservoir of some sort. Remote brake booster?
yes i know exactly what you want to do, because that is what i was doing in the begining, all day car but prepared for track.
for that prupouse the best suspension is the TEIN flex with EDFC with 18kg front 9 or 10 kg rear springs.
the problem is allways you will want more.... hahahaha
if i do it again i will use a seq gearbox ofcourse but i will use the Quaife gearbox but the Helical one, lot less noisy.
the 2jz is heavier than the 7m, but with the 7m dont forget to use a special pan or dry sump.

the pump on the passenger foot well is the electric steering pump but maybe it will be moved to the back
it dotn have brake booster.
 

te72

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Running a dry sump 1jz here actually... only one in the world that I'm aware of, because most people who dry sump Supras are smart enough to do it with a 2j haha.

I'd consider a sequential, or a twin clutch, but deep down I really like manually shifting. It's a lot more involving.

Electric power steering pump, very interesting. So, the pump is driven by an electric motor, but you still have hydraulic steering? Good solution...

Personally I'm trying to get as much weight off the nose as I can, and relocate it to the area behind the front seats. Low and centralized for good weight distribution. I've gone so far as to increase the weight in the back by a bit, just to shift that balance to the rear.
 

josbeat

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what did it come in at?
1170 kg with 20 ltr fuel, street tyres ,extinguiser and some other stuff what isnt fitted before , like the windscreen washer bottle and the exhaust wrapped.
the driver or copilot dosnt make any difference on the weight balance now is 52 front 48 rear. soon i will check with full tank,
ohhh!! i just remember that the flat floor is not fitted! that will be another 15 kg more or less. puff where to remove 15 kg? because i like the flat floor....
 

josbeat

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i been test driving the Supra on a mountain road , firts atemp was to test the coolant system but in the end i tested the handling aswell.
the coolant system works well but i need to tell that the outside temp was arround 12 º but i been driving on a slow trafic so with a minimal air flow due a slow speed and close to other cars the temp allways was under 80º with a 88º thermostat so .... good .

handling . difficult to say if is good or bad, but i can tell that it turns so fast really fast , to soon to say if it oversteer or if it turns like a hell! only i can say is .... NICE!!
 

Piratetip

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Nice underbody!

That front strut brace back to the firewall has what looks like a production sticker on it with PN# and Toyota something..something cant read it.
Looks to be in German.
Was that an aftermarket part that was available?
 

josbeat

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thanks!

the strut tower bar is a customized German bar for MK3.
dont remember well the brand.
 

josbeat

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first test at the track report:
the engine is...WOW!
the chassis is...WOW!
the.... WOW!!
the first impressions was very good, really good!.
i will need to check the rear diff again beacuse y runs smooth at low and medium speed but a little noisy at speeds over 200 Kmh.
 

josbeat

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Piratetip could be the vibration i feel at high speed the driveshaft critical speed problem??
my driveshaft turn mutch more revs than most because my rear diff ratio is 5.29 .
 

Piratetip

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Yes, you could be hitting the 1st or 2nd harmonic.
Have you used the calculator to check this?

Also what are your driveshaft dimensions?
1 piece / 2 piece ?
Aluminum? Steel?
Diameter? Length?
 
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josbeat

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Yes, you could be hitting the 1st or 2nd harmonic.
Have you used the calculator to check this?

Also what are your driveshaft dimensions?
1 piece / 2 piece ?
Aluminum? Steel?
Diameter? Length?
40" long aluminium one piece QUARTER MASTER drivedshaft and i think it is 3.50" diameter but dont know the wall.
 

Piratetip

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Can you ask the manufacturer what the wall thickness is they used?
Also the grade of Aluminum?
 

te72

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Still absolutely loving this, under 1200kg must feel amazing in this chassis.

May I ask how you attached the flat floor? I have been scratching my head for a long time trying to figure out how to do that to my car. I think the exhaust on a typical Supra would prevent a perfectly flat floor...
 

josbeat

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hi! yes it is amazing. believe me.

in the Supra, using both chasis rails is easy to do the flat floor with some riveted nuts but the exhaust must to be very well done , with some oval parts and closing it to the chassis so it must to be used a good heat shieldling like this
https://www.ebay.es/itm/Heatshield-...e=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649

allways is possible to use spacers to lower the floor sheets to get more space. in the middel to the gearbox suport and at the back with a pair of aluminium plates here and there.....
i am not using spacers but i was thinking to use it before, not using spacers because i am lowering the car a lot using a low profile slicks and semi-slicks with a hard springs.

regards!
 
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Piratetip

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Piratetip could be the vibration i feel at high speed the driveshaft critical speed problem??
my driveshaft turn mutch more revs than most because my rear diff ratio is 5.29 .
Have you used the calculator I created yet to see where your 1/2 critical speed is with your driveshaft / final drive ratio / transmission ratios / wheel size ect...?

I tried estimating with the limited amount of information you gave but its probably not accurate.

I would guess you are hitting 1/2 critical speed @ somewhere around 6,700 - 6,900 driveshaft RPM.
 

josbeat

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Have you used the calculator I created yet to see where your 1/2 critical speed is with your driveshaft / final drive ratio / transmission ratios / wheel size ect...?

I tried estimating with the limited amount of information you gave but its probably not accurate.

I would guess you are hitting 1/2 critical speed @ somewhere around 6,700 - 6,900 driveshaft RPM.

i am waiting to know the driveshaft wall thikness and the quality of aluminium . they dont have any information about it in the web.

uhmmm if the engine have 10.500 rpm rev cut and the 4th gear is 1:1 ratio....the driveshaft will rotate at 10500 rpm but in 5th will be more and in 6th will be over 12000 rpm !!!!
i been looking and " i think" that the critical speed could be arround 11.000 rpm of my Driveshaft looking the chart of PST company , i had one of those from that company before and the ends are welded but the one i have now the ends are riveted to ensure less material fatigue with the welds, the rest looks same.
i have one in carbon fiber that can be trimed to the new distance and looks like those have highers critical speeds yes?
thanks for the helps.

http://pstds.com/critical-speed-chart/
 

Piratetip

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What are your tire sizes to determine wheel diameter?
Also what vehicle speed do you typically notice the vibration?
This could help pinpoint where its coming from.

Easier to back calculate driveshaft RPM from wheel diameter and final drive ratio.

Carbon fiber will pretty much negate any issues with critical speed for your length driveshaft.
 

te72

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Thanks for the info on the flat floor mounting, it confirms what I was thinking. I have a welder and I'm not as afraid to use it now as I once was, I think I can do this, if I can come up with brackets that I feel will keep the sheets on the car. The oval exhaust is something I'm considering as well, simply to allow a flat floor, because round tubing just isn't going to cooperate with that idea haha. Plus, considering moving the exhaust exit to the right side of the car, as opposed to the left, so I can relocate my oil tank to free up some room and redistribute more weight to the rear.

As far as your driveshaft issues, I'd recommend using that carbon fiber shaft if you have one and can make it work. Less harmonic issue potential, and it's yet another way to lose weight! If I recall, my stock shaft was somewhere between 29 and 30 lbs (~13.5 kg), the carbon fiber one I have weighs 11.2 lbs (just over 5kg), it's almost spooky to hold in your hands...
 

josbeat

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What are your tire sizes to determine wheel diameter?
Also what vehicle speed do you typically notice the vibration?
This could help pinpoint where its coming from.

Easier to back calculate driveshaft RPM from wheel diameter and final drive ratio.

Carbon fiber will pretty much negate any issues with critical speed for your length driveshaft.
rear tyres are 315/30 18" 25,6" diameter from Bfgoodrich web catalog.
6th have 0.762 overdrive ratio and the diff is 5.29:1.

the speed when it starts is arround 200 kmh.
 
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Piratetip

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So with those specs your driveshaft speed would be 8,733 RPM @ 200km/h or 125mph.

Critical speed calculations don't match up with that but don't know the full specs on the driveshaft yet.

Calculated:
13,923 RPM Critical Speed
6,961 RPM 1/2 Critical Speed

Using:
40" length
.125 wall thickness
3.5" Dia
Alu - 6061 w/ density of 0.098
 

josbeat

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So with those specs your driveshaft speed would be 8,733 RPM @ 200km/h or 125mph.

Critical speed calculations don't match up with that but don't know the full specs on the driveshaft yet.

Calculated:
13,923 RPM Critical Speed
6,961 RPM 1/2 Critical Speed

Using:
40" length
.125 wall thickness
3.5" Dia
Alu - 6061 w/ density of 0.098

Thanks!
maybe is the rear diff , it have all bearings new and new crown and pinnion but that is not a easy job so i will double check that all is ok with it.
 

josbeat

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the Albun in Photobuckett are deleted sorry
and in my computer i lost many photos aswell but i can try to make a new one. give me time.
 

josbeat

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the lattest news are ...( i cant stop! )

i just bught a new front suspension kit, it is made for Drifft but i think i can use it for closed circuits aswell .
i am looking to wide the front track with long suspension braces and at the back with a deep dish wheels.
we will see the results soon.
the most difficult will be to cover the wheels with a nice set of weel archs , i bought a set of and i will see how it will look but if some one have an idea or design of a wide race supra , please let me look at it .
i like to see a supra with the look of the new Lexus race car.
 

josbeat

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the car weight at the end , 1190 kg with fuel and 1260 kg with me inside jajaja!. i can adjust the weight balance from 52 to 50 but not less than 50% at the front.
next project is to remove the front of the engine bay and build a tubular one.
how many Lbs do you think i can remove from there??
 

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What about the s2 wide body fenders. There about inch wider front and rear. Would make it easier to widen the track a bit without needing super wired sized wheels.
 

josbeat

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What about the s2 wide body fenders. There about inch wider front and rear. Would make it easier to widen the track a bit without needing super wired sized wheels.
i am looking to have a similar track wide like the GT3 cars and it is about 1620 mm
http://www.intercontinentalgtchallenge.com/car/1
changing the last number on this link we can see the different cars specs

1620 mm is maybe a lot but 1580 1600 mm is what i am looking , for that reason i bought this kit
https://fat-dp.pl/en/products/lock-kit-for-toyota-supra-mk3-65-degrees/
they told me that arround 50 mm wider each side... so i need minimun 50 mm 2 inch wider body each side.