DeltaV

Toying with this idea currently.

STS(/STC) is dominated by Miatas and CRXs. Could a DC4 possibly run with either? It has a touch more power, but is heavier. Most of those cars run on 195 R1Rs, but Toyo is making a 225 45 15 R1R that looks like it would work great with a DC. So more tire, more power, better than less tire, less power but lighter?

Thoughts?

mdb4879

It's not going to happen. Even a DC2 GSR wouldn't be able to keep up. There's about a 600lbs weight difference to overcome. Even with a wider tire, you're still limited to a 7.5" wheel so you won't really get the full potential out of the tire. The STS class runners have their car prep down to a fine science, and their power to weight ration is close to that of a stock GSR. Most of them are already bouncing off the limiter at 60mph for a large portion of a national course. I wanted to do an STS DC2 this year, but after looking into it a lot, there are too many reasons not to unless you're only in it for fun.

DeltaV

What about a GSR on the 225s?

I think the main reason why the current STS cars are so dominant is because nobody has bothered to try anything else.

mdb4879

Even a GSR couldn't keep up. Autocross is all about handling, and that 600lbs is a big difference. The 225's won't help much because you'll be pinching them on a 7.5" wide wheel. If I had to take a guess, I would think everyone will be moving to 205's this year anyways. The only reason people ran the 195 R1R was because it had a stickier compound than other tires in it's class. Even from the 205 R1R.

If you really want to give it a try, just do all the same things the current STS guys do. Your weight reduction is limited due to option packaging, and your spring rates will be different. But all in all the car will be set up very similarly. But be for warned, an STS Civic isn't just fast. It's FAST!

Davidss

Speaking as someone with a lot of experience in STS (national champ 2012+2013) I applaud your out of the box thinking. But I would have to agree that the DC2 doesn't stand much of a chance at the national level.

In autocross acceleration potential right around 30mph is the most important, and although the B18C does make much more power at high revs at low RPM it doesn't make any more than the surprisingly torque-y D16A6. So with the weight penalty at every low speed turn the EF will out accelerate the DC2.

But don't take my word for it. Jason Rhoades has an excellent page with great detail on comparing acceleration potential between cars. He even has a spreadsheet in which you can plug in dyno numbers to get your own results:
CVD 3a -Rolling Accel (simple) « J-Rho's '67 Camaro Z28 STX build

FYI the DC2 is being moved to STX in response to many requests from DC2 owners. Although STX is sometimes a slightly faster class the car can use much wider wheels and tires and add an LSD.

Xian

+1 ^^^.

The GSR won't be "the" car to have in STX but it won't be any less competitive than it is currently in against the EF in STS/STC. IMO, at least it'll be way the hell more fun in STX with wider wheels and a diff. I'd even bet that an early car wouldn't give up much if any weight against the ITR. Heck, the power band may even be better than the R for that matter.

_decker

iTrader: (15)

I've ran my '01 GSR locally and in a few pros and tours and its not worth the frustration. At 90% prep I was at 2450 on 225's with 1/4 tank. Maybe you could get down to 2375-2400 with pimpy wheels, aluminium shocks and custom everything else but the biggest holdup aside from weight is ECU tuning on the OBD2 cars.

Xian

I figured out a couple tuning options that I believe would be legal for the OBD2 cars. Obviously there's the piggyback option called out specifically as legal. The other option would be to go to a Hondata and then use the "modify sensor signal" allowance to install an OBD2 emulator. That's without going down the road of a custom, standalone ECU...

Christian

Colin

iTrader: (1)

A friend of mine was campaigning a 92 RS in STS years ago and they were doing very well (quite even with the EF guys). He also had a 92 GSR and he said it was no comparison and the RS was faster - it's lighter, a little less horsepower but more torque, better gearing and you didn't need to be in vtec all the time.

_decker

iTrader: (15)

All I know is I couldn't just throw in a OBD1 ECU with Hondata. Once I figured out the car wouldn't be competitive I stopped looking at piggyback systems and custom wasn't even on the radar. The car is way too nice to hack up the wiring and I was looking for a bolt in solution. I'm interested in the Hondata solution though. PM me if you're willing to share.

Xian

Yeah, I did some research on it when I was playing with an 01 ITR in STX. Basically the rules require "OBD2 functionality" be maintained. As you mentioned, this precludes dropping in an OBD1 Hondata and calling it a day *but* there's an additional allowance for modifying sensor input/output. My read is that it would allow you to wire in an OBD2 port emulator so that "functionality" would be maintained even with an OBD1 ECU.

I posted some of the details on this over on the ITR Expo forums. Shoot me a PM and I can dig up the links if it'll help.

Christian

redGSRguy

Here is Christian's thread
ITR Expo Forums: Hondata & OBD2 Port Question

Xian

Thanks!