autocrossers - need advice

[dave421]

Well after about 1 1/2 years I've started autocrossing again. Took my 07 Si Sedan out this weekend for it's first event. It wasn't bad but I definitely need more time behind the wheel (wow is this thing big. I was trying to drive it like my old SM2 CRX and she didn't like that too much :) ).

Anyway, I'm thinking about sticking in G-stock with this car (I'm getting older and mods aren't as big a deal anymore). BUT, I'm having a hard time deciding on mods.

Plans:

-K&N drop-in
-Custom exhaust (hate fart cans so I'll be going with an ES Oval, no-name turbo, or Hytech twinloop)
-Lightweight wheels & Hankook RS2s (going to wait at least a year for R-comps)
- Koni yellows whenever they FINALLY get them on the market.
- crash bolts

I've got 3 questions. I know people w/ bolt-ons & reflash have been running up to 3" exhaust. Seems like overkill for a stock car though. What are you guys finding success with? 2.5"?

I'll be buying another set of wheels & tires strictly for auto-x. I know I can squeeze some 235s in there (think some have gotten 245s?). What size are you running? I have never run a staggered setup although with the power in this car, I'm considering it since I can't run a larger rear sway. Any recommendations. Also, I'm doing the RS2s over the Azenis just for the slightly more gradual break-away. Anybody have some recommendations on starting tire pressures on this car as well?

I've never used crash bolts as my previous cars will all double wishbone. I know I can get up to .8 degrees out of these which is REALLY seems to need but how many are you using? 1 per side or 2?

I know this is a lot to ask of you guys but if anyone can offer some help or advice, I'd REALLY appreciate it. I thought I was done autocrossing once I got into sport bikes but now I'm thinking about how a Ninja 650 would pay for my mods and a year of autocross.... Thanks in advance for any help you guys can give.

[Jardiniboy]

Get yourself rear camber kit and 2 sets of camber bolts for the front. After get better alignment.

As for Tires I would recommend the Bridgestone re01r tires.

[BigDog]

Originally Posted by Jardiniboy

Get yourself rear camber kit and 2 sets of camber bolts for the front. After get better alignment.

As for Tires I would recommend the Bridgestone re01r tires.

Can't run the rear camber kit in stock class.

[BigDog]

Originally Posted by dave421

I've got 3 questions.

1. A stock class exhaust isn't going to gain you much power. The number one benefit will be weight savings. So, if you are going custom, go for the lightest thing you can stand sound wise. I'm personally going with the Magnaflow set up for the street and I will remove the rear section and add a turn down for non-noise sensitive events.

2. Try a staggered set up. 235 or 245/40-17 front, 215 or 225/45-17 rear. Falken RT-615s are always a good bang for the buck tire. The Yokahama Neova and Bridgestone RE-01R are also nice, but pricy.

3. You will need 2 sets of camber bolts to get the max camber in the front which is a whopping .7 to .8.

Good luck and have fun.

[honda93]

Originally Posted by BigDog

1. A stock class exhaust isn't going to gain you much power. The number one benefit will be weight savings. So, if you are going custom, go for the lightest thing you can stand sound wise. I'm personally going with the Magnaflow set up for the street and I will remove the rear section and add a turn down for non-noise sensitive events.

2. Try a staggered set up. 235 or 245/40-17 front, 215 or 225/45-17 rear. Falken RT-615s are always a good bang for the buck tire. The Yokahama Neova and Bridgestone RE-01R are also nice, but pricy.

3. You will need 2 sets of camber bolts to get the max camber in the front which is a whopping .7 to .8.

Good luck and have fun.

I'm not a fan of staggered setups only because I know how hard I work the front end of my LX to keep up with (and often beat) the base MINI. Running four of the same-sized tires allows me to rotate them to a new corner each event ensuring even wear and consistent performance. Otherwise, I'd be going through 6 front tires a season and only two in the rear. No thanks... I can counteract that with the Bilsteins, my rear toe setting, and tire pressures.

Since you're on street tires, I'd really advise against it. Especially in the Si, that's a lot of nose weight coupled with a pretty much useless LSD to work a street tire.

BTW, Jardiniboy was wrong. In Stock you cannot play with the rear camber arms at all. Other than shocks and alignment settings, the rear stays basically as it rolled off the showroom floor. For the front camber bolts, they can only be the OEM Honda bolts, the SPC bolts are NOT allowed.

Anthony "Mario" Crea
NNJR-SCCA

[BigDog]

I only advise a staggered tire set-up on the Si. More power, more weight on the front. I run 225/50-16s on my HS LX all the way around. RT-615s for the street, 710s for the track. We might try a 245 on the front later next year, but I'm not sure if it will be needed. If we can stay Nationally competitive on the 710s, we will stick with them. I like being able to rotate them and the price came down some, especially compared to the A6.

Back on topic, Tony could be right. Running a 235/40-17 all the way around could work fine if you can adjust the shocks and alignment accordingly. Then you can rotate your tires and even drive them on the street.

[honda93]

Originally Posted by BigDog

I only advise a staggered tire set-up on the Si. More power, more weight on the front. I run 225/50-16s on my HS LX all the way around. RT-615s for the street, 710s for the track. We might try a 245 on the front later next year, but I'm not sure if it will be needed. If we can stay Nationally competitive on the 710s, we will stick with them. I like being able to rotate them and the price came down some, especially compared to the A6.

Back on topic, Tony could be right. Running a 235/40-17 all the way around could work fine if you can adjust the shocks and alignment accordingly. Then you can rotate your tires and even drive them on the street.

245's fit on the Si. If the OP runs them all the way around, he'll be fine.

[Jardiniboy]

Thanks guys clearing me up about the rear camber kit in stock class.

[autoxmnstr]

im running a 3" exhaust and its perfect, cant ask for anything else. the guys at stoopidfast did a dyno run on the k20 n/a and they found the best numbers came from a 3".
I run 235/40/17 rt615's all the way around ( r compounds i cant afford).

[dave421]

BigDog, that was my plan with the exhaust as well. Part of the "custom" was moving the rear flange & adding a hanger (haven't even checked under the car yet so there may be one close enough) for a downturn to attach & hold up. Figure it's available and won't cost much so I might as well try to gain a few hp and hopefully drop about 10-15lbs.

Honda93, 245s fit? That's the first time I've seen that. Do you know the offset that they'll work with?

As for the tires, I would prefer to stick with the same size all the way around. I've got 4 different clubs around me so I'm hoping that I'll be running about 2 events a month next year so I'm sure tire cost will become a factor. Once I've learned the car (and relearned everything I've forgotten) and move to r-comps, I might go staggered if I need it to stay competitive.

Camber-bolts, anybody have the part number sitting around? Called my local dealer on Friday and got a "Huh?" in response. I've always called them crash bolts but they weren't familiar with them or camber bolts.

[Highrev1]

Thier Factory SLIP bolts...2 of them are legal.../I will find the P/N soon for you

245's fit on the factory offset, I have ran them without an issue.

THe staggered setup is good to help induce rotation, due to one of my toe adjustments was limited Factory defect I am sure, but the staggered setup did help gain the rotation needed, although not enough to compete against the minis

[dave421]

Your toe adjustment was limited? Great. I haven't started playing around with any toe settings yet. Are you pretty sure that yours is abnormal or have others had this issue as well? That's not something I was planning on. Perhaps I need to find a new alignment guy before I order tires (just moved to a new town 3 hours away from my old guy ).

Slip bolts. I had forgotten that one. Thanks. I'll give them a call tomorrow and see if they have that listed.

[honda93]

Originally Posted by dave421

Honda93, 245s fit? That's the first time I've seen that. Do you know the offset that they'll work with?

A guy who used to have an Si had 245 Hoosiers all the way around on the OEM 17" Si wheels.

[Gonzo]

I have seen a Type-S with 255's that supposedly didn't rub.

[RANGERSi07]

I run 255's in the front with 225's in the rear (Yokahama Neova)...dave was that you with the 4door white Si autoX'in this past weekend in sanford? BTW I suck at driving but another guy there managed to hit 78(<--6 years of autocross) with no cones driving my car, only proves its the 90% drive 10% ride, best I could muster was a 86.

[dave421]

Yeah that was me. I was so rusty out there. Unfortunately I'm going to miss the next one in 2 weeks. I need some more seat time badly but I fly out to Vegas for SEMA that day.

[BigDog]

Camber bolt part # is:

04512-SNA-305

Eight of them will be at my house today.

[dave421]

Great! I had an insane day at work and never got around to calling. Should be much easier now.

Oh, and EIGHT? Any particular reason you got so many spares? Something I don't know about slip bolts? This IS the first car I'll have ever used them on.

[BigDog]

Originally Posted by dave421

Great! I had an insane day at work and never got around to calling. Should be much easier now.

Oh, and EIGHT? Any particular reason you got so many spares? Something I don't know about slip bolts? This IS the first car I'll have ever used them on.

They're ordered as "each", so I got an extra set. They can't be re-used, so if we want to do something later, or if they slip or break, I've got extras.