Rally-x/US Rally Cross Setup

[schroder]

Hey guys,
I've been on the forum lurking for a while but never really got much going. I'm looking into a rally-x type car for the upcoming season, and have a pretty nice deal on a 240 with a single slammer in it. I know the difficulties (Pronounced - Fun) that come with running a RWD off road...so I'm not looking to be talked OUT of running the car. What I am looking for is first hand experience. How the car compares to FWD cars; what modifications would be most recommended aside from basic power bolt ons, GR2s, and tires; any suggestions with the car in general to help make the jump a little better. The build is wide open as we are not SCCA affiliated, so the only things that limit class are 2wd or 4wd along with street tires or dirt/gravel/snow specific tires (aggressive offroad type tread). Thanks in advance for any help or advice!

[IanS]

I would have responded to your PM, but you dont have the enabled. You can send but not receive, so this will have to do.

What style Rally X are you talking about, Global European style, or traditional american style?

If you are doing traditional. Get some decent dampers, run stock springs, and get the nobiest snow tires you can get your hands on. Winterforces work very well. I would removed the rear sway bar. Try to get it to dig for better traction, then force rotation by clutch kicking, or if you have the power, you can just throttle over.

Try to broaden the power band. Many rally crosses are so tight you will be limited to 1st and 2nd gear, occasionally 3rd. Being able to make power all over the rev range will allow you to shift less, and keep power on more.

If you are doing european style, then its a whole different build, and you will need to start with a cage. But that is a whole other post.

[schroder]

LOL...Thanks. I didn't know I didn't have them enabled, so I'll have to look around...plus this may help the community and thats never bad Its the US style rally cross, and most are pretty tight from what we run. I was looking into I/H/E and reducing as much rotating weight as I safely could. Is there anything else that would help the car expand the powerband specifically (on the 24e?). Also, what would help to get the rear to dig (I assume squat) better than just running stock springs? Also, since suspension is so important with rally cross, would a poly bushing set help or hurt the car? I know it reduces flex, and I assume it would benefit by making the car a little more predictable on the unpredictable surfaces, but didn't know if it would be a negative at all. Thanks for your help with everything man...I'm sure I'll have more questions about it, but that really helps!

Ok...One more...how competitive can the 240 be with the 2wd cars, obviously with decent tires.

[IanS]

LOL...Thanks. I didn't know I didn't have them enabled, so I'll have to look around...plus this may help the community and thats never bad Its the US style rally cross, and most are pretty tight from what we run. I was looking into I/H/E and reducing as much rotating weight as I safely could. Is there anything else that would help the car expand the powerband specifically (on the 24e?). Also, what would help to get the rear to dig (I assume squat) better than just running stock springs? Also, since suspension is so important with rally cross, would a poly bushing set help or hurt the car? I know it reduces flex, and I assume it would benefit by making the car a little more predictable on the unpredictable surfaces, but didn't know if it would be a negative at all. Thanks for your help with everything man...I'm sure I'll have more questions about it, but that really helps!

Ok...One more...how competitive can the 240 be with the 2wd cars, obviously with decent tires.

Reducing the cars weight overall should be your biggest modification. Every ounce counts. Since you wont be requiring a cage, getting the car to be feather light will be your best chance at speed. As for building more useable power, I would look at increasing compression, and re tuning. If you were to increase compression significantly and make a switch to E85, you could run lots of timing to help build power early.

Leave the suspension stock, rally cross is about getting traction where there isnt. Look into what guys do to go fast on ice.

Being competitive is a toss up. By the books a fwd car will be faster on a rally cross course if power and weight are the same, but the right driver can do incredible things. When I built my car, people told me I would lose because RWD cars are only competitive with FWD cars when power levels, and speeds get higher. At our first event, I was able to outrun much of the FWD field including a couple cars with more power, and more experience then myself.

My advice. Gut the car as much as possible, lose everything. Get a good set of winterforces, and some bolt ons, then get out and drive. Only way to know how she will do, is to try.

[schroder]

Sounds awesome! The only thing really that worries me (mainly due to me being competitive), is that the classes for 2wd are split by All Season tires, or knobby tires. There isn't a single FWD car that runs anything other than all seasons, so I may go out and see how it does on some standard All Season M+S treads. Worst case, I switch to the snow tires and always take a podium. Best case, I can fight some of the guys with FWDs. Also, I know you were talking about raising compression...what's your opinion on a mildly boosted (say 9psi) motor with an Evo 8 size turbo? I know it would spool very quickly on the 2.4, and have usable power throughout the majority of the rev range. My biggest fear would be that it hurts more than helps due to the tires always wanting to spin...not that they already dont on dirt. Thanks for the help again, and best of luck in your next rally!

[IanS]

Sounds awesome! The only thing really that worries me (mainly due to me being competitive), is that the classes for 2wd are split by All Season tires, or knobby tires. There isn't a single FWD car that runs anything other than all seasons, so I may go out and see how it does on some standard All Season M+S treads. Worst case, I switch to the snow tires and always take a podium. Best case, I can fight some of the guys with FWDs. Also, I know you were talking about raising compression...what's your opinion on a mildly boosted (say 9psi) motor with an Evo 8 size turbo? I know it would spool very quickly on the 2.4, and have usable power throughout the majority of the rev range. My biggest fear would be that it hurts more than helps due to the tires always wanting to spin...not that they already dont on dirt. Thanks for the help again, and best of luck in your next rally!

Winterforces should be in the A/S class. IIRC Knobby tires would be considered true gravel tires, which dont work well because they never come up to temp on such a short course.

A small turbo might work well, but it would require a different driving style. With NA, you can just stomp the throttle to force rotation, but with a turbo car, this would cause power loss, so you have to clutch kick. This is a lot harder on the driveline. Turbos also hurt reliability, and you cant win if you dont finish. If you are truely looking for more power, look for more displacement. A VG30E could be cheap, and would make lots of useable torque, and you wouldnt be stressing it to hard, making it reliable. If its just a race car, set it up with a carburettor, and you wont need to worry about wiring.

[schroder]

You sir, are a wealth of information. I'll have to look into the vg30 swap. I guess I didn't mention the displacement rule on classes...2400cc is the limit for the low end 2wd, and then every thing else. Basically six classes where we are...<2.4 2wd, >2.4 2wd, and AWD/4wd. After those there, they are split between standard all season tires and snow/mud/gravel. I'll see if I can post a rule up, but I'll talk to the guys about it. Hopefully it'll work to keep me with the other cars.

Street Tire Classes: Street Tire. For the purposes of this class, a "street tire" is defined as a "summer use" or "all-season" tire from any manufacturer that does not have an knobby or overly aggressive tread pattern, as determined by the Rallycross VP or his designate. Specifically excluded are snow tires, rally tires, mud-terrain or all-terrain tires, and any tire with a knobby tread pattern.

So I'll have to see if they'll throw me a bone since I'm RWD...not really counting on it though, and I'd hate that to be the excuse people have if I won. But I'll have to look into carbing the VG...I hadn't really heard of it, but I know about anything is possible with cars...just not always practical.