Building an SC400 race car and have some questions

[Matt Starr]

So first of all how's it goin everyone, Im Matt and I'm from Denver. I finally decided recently that I'm going to get back into racing and the car that I've wanted to build into a race car since I was 16 is an sc400. So I was wondering if you guys could post some links to good threads that I should read through. I've been reading around on this site and others but you guys might have some better suggestions on threads. Also if anyone knows of anything in particular that I should know before starting this build please do share. Thanks
Oh and does anyone know of a good thread about sc400/300 diets. The first thing Im doing to my sc400 is getting rid of some wieght.

 

[JuNiOr24]

Welcome!!! There are of a lot of threads out there especially on this forum you just got to use the search option. Even in the articles they provided already. What kind of racing??Budget?? FI or NA?? I wouldn't get rid of weight yet until your all planned out and ready. Keep us updated and keep searching.

 

[Matt Starr]

Welcome!!! There are of a lot of threads out there especially on this forum you just got to use the search option. Even in the articles they provided already. What kind of racing??Budget?? FI or NA?? I wouldn't get rid of weight yet until your all planned out and ready. Keep us updated and keep searching.

I've searched this forum quite a bit, I was just wondering if anyone knew of some really good threads I should check out that I might havent seen yet. Im mostly going to start out with "drop in" races at the tracks in CO and as I build my SC I'll decide what I want to do. Im deffinatley gonna do FI to my SC but I still cant decide between TT or s/c.
So far I've only pulled the seats out and put in a pair of racing seats but I am trying to keep it "driveable"

 

[XR8tt]

What rules are you racing in and do you want it road registered ??
Why I ask is you could space frame alot of weight out of body...

 

[JBrady]

You may already be aware but the SC shares suspension with the MKIV Supra. Lots of Supra options that will work to create a very impressive handling SC.

 

[Matt Starr]

I'm not sure what class I want to race in yet. I do want to keep it street legal at least for awhile so that I can still take it up into the mountains to test it instead of always having to pat to go to the track.

I have been reading about the supra similarities which is really nice cause there's a lot more racing grade parts available for it than there is for the sc. What else do you know of is cross compatible with the sc and the supra?

 

[spdrcr771]

Im going to assume that your talking DRAG racing. Not ROAD racing right.

 

[stevechumo]

You may already be aware but the SC shares suspension with the MKIV Supra. Lots of Supra options that will work to create a very impressive handling SC.

John is correct.

Anyway, the SC suspension is really soft and made for crusing. Therefore, you'll need to beef it up to handle the agressive driving. The best is to use Supra parts.

 

[Matt Starr]

Im going to assume that your talking DRAG racing. Not ROAD racing right.

No, just regular old grip racing on a track. Even though its not very likely, my ultimate goal is formula 1. I've never really been a fan of drag racing.

 

[XR8tt]

Track is more orientated towards GOOD handling and brakes..
Which would mean way big 370mm+ brake rotors and 6 / 8 piston calipers..
Coil over springs with at least 600 lb rating...
With shocks to suite. Way way above what it has now with [adjustable] sway bars sorted to give best handling balance..
Weight is the main part, the lighter the better which makes vehicle more nimble...

 

[spf_lexus]

Track is more orientated towards GOOD handling and brakes..
Which would mean way big 370mm+ brake rotors and 6 / 8 piston calipers..

Not necessarily so. Gotta remember the MKIV supra had the shortest stopping distance ever documented until the carrera GT stopped about 4 feet shorter. Just run ss lines + race pads + race oil. Strip the SC down to low 3000lb, some stiff coilovers: 14-18kg front, 8-12kg rears, trd sways, supra TT front + rear brake swap, LSD, 285mm rear tires, 255mm fronts.

Those should be plenty to negate the 3000+lb disadvantage.

 

[XR8tt]

Not necessarily so. Gotta remember the MKIV supra had the shortest stopping distance ever documented until the carrera GT stopped about 4 feet shorter. Just run ss lines + race pads + race oil. Strip the SC down to low 3000lb, some stiff coilovers: 14-18kg front, 8-12kg rears, trd sways, supra TT front + rear brake swap, LSD, 285mm rear tires, 255mm fronts.

Those should be plenty to negate the 3000+lb disadvantage.

To stop once yes but to have advantage and to be able to race for more than two laps.. Std brakes are rubbish...
Add good lsd , tighten up std if fitted...

 

[JBrady]

To stop once yes but to have advantage and to be able to race for more than two laps.. Std brakes are rubbish...
Add good lsd , tighten up std if fitted...

Certainly the stock SC brakes are terrible for road racing conditions.
How long do the stock Supra brakes last road racing conditions? Stock Supra Turbo front brakes 12.6" (320mm) 4 piston calipers

 

[Matt Starr]

Thank you all for your replies. Right now I'm running brembo drilled and spotted rotors, brembo calipers and oem Denso pads. I'm still on the oem suspension which is complete rubbish btw but I still can't decide what I want to do with it yet. Right now I'm more worried about losing more weight. When it was stock it weighed in @ 3400 w/o me. I've got it down to 3078lbs now but I need to get it under 3k to qualify for the class I want to compete in but the only other thing I can think of to lose that 78lbs is a carbon fiber hood but I can't find one. Not to mention I still have to install a roll cage.

 

[spf_lexus]

Mr. Ueno built his race-spec Vertex sc300 at 2900lb but it required a lot. It was stripped completely bare, all looms removed, single carbon seat, carbon doors + hood + trunk + fiberglass vertex kit. sunroof shaved and of course a manual trans.

I have stock sways w/ heim'ed endlinks and 14kg/8kg coilovers and if their maxed out, I have next to zero body roll. I believe a set of TRD/Titan sways are too much for the street. A set of Titan sways will kill any and all roll you have right now.

Check out Buddy Club. They make a race-spec coilover for the SC at 18kg fronts and around 10-12kg rear. This is too stiff for street use but excellent for track.

Carbon hood will save 35-40lb over stock. Plenty of companies out there for SC/soarer. Seibon alone offers 3 types of hoods for the SC.

 

[cribbj]

Certainly the stock SC brakes are terrible for road racing conditions.
How long do the stock Supra brakes last road racing conditions? Stock Supra Turbo front brakes 12.6" (320mm) 4 piston calipers

John, my data shows the following for the twinturbo model Supra:

Rotors:
Fronts (diameter x thickness): 324 x 30 (mm) (or 12.72" x 1.18")
Rears (diameter x thickness): 324 x 16 (mm) (or 12.76" x 0.63")

Calipers:
Front piston diameter: 42.85mm x 2 x 2
Rear piston diameter: 40.45 x 2

@ Matt: if you don't go with a full BBK, I would at least look into using the LS400 calipers, which are aluminum, whereas the Supra's are cast iron. That alone could easily save you 20-30lbs, and best of all, it's unsprung weight you're reducing.

 

[XR8tt]

John, my data shows the following for the twin turbo model Supra:

Rotors:
Fronts (diameter x thickness): 324 x 30 (mm) (or 12.72" x 1.18")
Rears (diameter x thickness): 324 x 16 (mm) (or 12.76" x 0.63")

Calipers:
Front piston diameter: 42.85mm x 2 x 2
Rear piston diameter: 40.45 x 2

Yep that's better...
If you fit coil overs the need for tuff sway bars are not 100% required as much.. Coil overs generally have height adjustable shocks which helps for on road ...
Depending on local road rules ?? Some heim joints on specific parts on your suspension tightens handing and driver response big time..
There are aftermarket calipers / rotors out of Japan which to me seem VERY cost effective..
Check EBay ??

 

[Matt Starr]

Lol, ok guys, I'm all good in the brakes department. I'm running front and rear brembos and they are amazing. Like I said, I'm more concerned about weight. My interior is completely gutted so there's not much more I can do there.
Who is Mr. Ueno? I would love to read about his sc300 if anyone has a link.

And just to be clear, I'm not street racing, the car is being built for track purposes only.

 

[spf_lexus]

Google search D1 vertex soarer. His name is "Takashiro Ueno". here's a link to the build. I know there are forums covering more of the details if your willing to dig:

http://superstreet.automotive.com/53208/130-0507-vertex-soarer-d1-drift-car/index.html


Have you deleted the sunroof? Its got to be 80-100lb located at the highest point in the car. The IS300 purists wont even consider an all-out build if the car has the moonroof option.