Rallycross build guidance wanted

We have a 93 beretta with a 2.2 and a getrag five speed that was bought to serve rallycross beater duty. We have ran it in SF and it was a blast but we decided to run one more race in SF and over the winter build it for MF. The reason for this is we have always been car guys that like goofing off out in the garage, not because we ever had illusions of being famous racecar drivers, and we feel it would be a more enjoyable experience with a more open set of rules for the car. Here are the constraints we are working in, we are very budget oriented, both for the monetary reasons but also because a beretta is never going to be a "fast" car no matter how much money you throw at it, so why throw good money after bad. We may spend a little more on things like a proper race seat because it could be transferred to a car better suited to racing in the future. Otherwise our plans are to see how much we can get accomplished on a small money outlay. So far our plans are to

1) Strip all unnecessary weight

2) Strut brace, probably home made

3) Skid plate

4) Port and polish

5) Cage, probably a simple four point. We have access to a bender and will make this ourselves

6) A decent seat with bolster support and harness, probably an expired set from a drag racer friend.

7) We kicked around the idea of welding the diff, is this a good or bad idea? This car doesn't have a title so it doesn't see any street time.

So give me some guidance, what other good bang-for-the-buck improvements should we be looking into? My teammate and I have a combined 20 years experience as mechanics and are decent fabricators so nothing is off the table, so long as its cheap. If you were in our shoes what would you add to the list?

Make sure the suspension is stiff enough to not bottom out all the time and lose its composure when things get rough. And figure out a good wheel / tire setup. And no steelies!

In reply to rslifkin:

Yeah, we need to do some research on what cars share the 5x100 bolt pattern we have and what would be a good junkyard option for wheels. I think subarus use that pattern, so I was hoping we could find some of those with good tires for what we are doing. Is wider always better for rallycross, or not?

Wider will do better on well-packed surfaces (hardpack snow, packed dirt). Narrow tires are good on surfaces that you want to dig through and grab whatever is underneath (a couple inches of snow over packed dirt, shallow mud).

Many (but not all) Subarus are 5x100, so that should definitely provide some wheel options.

Put good shocks on it, buy better tires, and get more seat time. Anything else is just spinning wrenches for the sake of spinning wrenches.

Tires are the single biggest thing you get when moving out of SF. Everything else is after that. Also, the SDAC guys taught me that welding a diff is good, but only welding the ring and spiders, but not to each other is better. If you do it right you get about 1/3 rotation before things stop in either direction. This helps transitions immensely. I never did race a diff set up like this, but I drove one around for a bit and it was better than a fully welded one.

In reply to Knurled:

We have new shocks ordered, we can't hardly wait to get more seat time, and spinning wrenches for the sake of spinning wrenches is pretty much what we do for fun

In reply to mazdeuce:

I've seen this method of diff welding, but it scares me. It seems like a sure fire way to break the carrier. How much have your friends used this method, and has there been any breakage?

mazdeuce wrote: Also, the SDAC guys taught me that welding a diff is good, but only welding the ring and spiders, but not to each other is better. If you do it right you get about 1/3 rotation before things stop in either direction.

That is exactly how you break things. Weld it all up or leave it open, but the shock loading from what you describe quickly results in push mode.

Knurled wrote: Put good shocks on it, buy better tires, and get more seat time. Anything else is just spinning wrenches for the sake of spinning wrenches.

What he said.

In reply to Knurled:

It's not perfect. The SDAC guys had some sort of trick that let things live quite a long time like this. They ran them on stage rally cars. I would like to rallycross a welded FWD car and see how it goes though.
Tires, shocks, diff, and then anything else that seems fun.

Knurled wrote:

mazdeuce wrote: Also, the SDAC guys taught me that welding a diff is good, but only welding the ring and spiders, but not to each other is better. If you do it right you get about 1/3 rotation before things stop in either direction.

That is exactly how you break things. Weld it all up or leave it open, but the shock loading from what you describe quickly results in push mode.

So would fully welded be an improvement over open diff?

gearheadmb wrote: So would fully welded be an improvement over open diff?

IMO, no, it wouldn't. It'll understeer like hell. A limited slip would be good, but welded front diffs are not so good.

Fully welded is definitely an improvement over open for rallycross. Just make sure you have spare axles and can change them quickly. And never apply full throttle and full steering lock simultaneously. Rack spacers to limit steering travel wouldn't be a bad idea.

I wouldn't waste time on the port and polish.

Stiffer junkyard springs and smaller or no front sway bar are other good ideas.

This car has a spool and did alright. https://youtu.be/ZT8rL24j-Ig?t=1m50s

Don't bother with a cage as it just adds unnecessary weight.

Second gen Neons have 15x6 wheels with 5x100 & 57.1mm hubs which should bolt right up.

As already mentioned, rally tires are your best bang for the buck. What type to go with & width is dependent on the surfaces you race on.

Stripping weight goes a long way too. I'd recommend keeping some form of heat for cold events & defrost purposes. If you ditch the side/back windows, I'd recommend replacing them with Lexan as a windowless car is an awfully unpleasant place to be on muddy, rainy days.

In reply to FooBag:

The Windows are staying because the car isn't always stored inside.

As for the cage, we want to use a harness and a) the cage is needed so we have something to attach the shoulder straps to and b) its very dangerous to run harnesses without a cage. With factory belts if the roof caves in you can lean sideways across the center console, with a harness you are stuck in upright position. The reason we want to run a harness is with the factory belt we put a lot of effort in staying upright and planted in the seat. It sure seems like it would be nice to just be strapped in tight.

mazdeuce wrote: In reply to Knurled: It's not perfect. The SDAC guys had some sort of trick that let things live quite a long time like this. They ran them on stage rally cars. I would like to rallycross a welded FWD car and see how it goes though. Tires, shocks, diff, and then anything else that seems fun.

Stage rally is a lot gentler on drivetrain parts than rallycross, IME. Stage rally is done on roads, we're not. Fewer passes on said roads so things hold up a lot better. A lot less driving at OMG 115%.

That's one of the things that makes rallycross so fun. You have to be fully switched on from the first run to the last finish, with no letup.

It's too bad the Beretta is a manual trans. You can swap the differential in an automatic in a half hour or so.

Knurled wrote:

mazdeuce wrote: In reply to Knurled: It's not perfect. The SDAC guys had some sort of trick that let things live quite a long time like this. They ran them on stage rally cars. I would like to rallycross a welded FWD car and see how it goes though. Tires, shocks, diff, and then anything else that seems fun.

Stage rally is a lot gentler on drivetrain parts than rallycross, IME. Stage rally is done on roads, we're not. Fewer passes on said roads so things hold up a lot better. A lot less driving at OMG 115%. That's one of the things that makes rallycross so fun. You have to be fully switched on from the first run to the last finish, with no letup. It's too bad the Beretta is a manual trans. You can swap the differential in an automatic in a half hour or so.

lol, I'm not sure I'd agree there. Stage the car is spending a LOT more time at high revs and with far more suspension compression stressing things like axles and steering. Not to mention much larger impacts jarring things loose, breaking motor mounts, etc. One of the bigger casualties of stage that usually isn't an issue with rallycross is shifters/linkages/clutch hydraulics since they're getting heavy use. That said, I'll agree that most stage carnage is from breaking suspension parts (or in our case, wheels) rather than from drivetrain breakage, especially on a FWD car. But it's all relative. Nothing in stage is gentler on the car than anything in rallycross. Just like autocross vs. road racing, really. There are more extreme forces in every measure.

Back to the original point about diffs, however...yeah, welded diffs may hold up better in stage (especially FWD) since you're not often at full lock or making ultra-tight turns. Though Corey has broken like 5 axles in his Volvo 240 with welded diff. For rallycrossing FWD, I'd probably just keep it open diff anyhow, especially if you're not shooting to be the top dog, and/or if your venue isn't generally muddy. Andy Thomas dominates our large region in an open-diff Celica and was very competitive at Nationals as well this year.

As to the "switched on" part, totally disagree. In 5 years of rallycross, I've never had an "OMG" moment (and I am not slow). In stage, I probably have 5 of them in the first 10 minutes lol...If you're not fully switched on in stage, you destroy your car on a tree. If you're not fully switched on in rallycross, maybe you hit a cone or spin the car.

They're different animals for sure, and stress cars differently. Rallycross definitely requires quicker steering and more looking ahead (since in stage you can't see more than 1 corner ahead usually). The skills are certainly different. I'm learning that firsthand, where my speed in rallycross has not yet translated to speed in stage. Going fast is a lot easier when there's no real personal/financial risk involved ;) Both are awesome in different ways and, to some extent, require different skills and car setup - which is why I still do every possible rallycross even with a fully stage-spec'd car.

gearheadmb wrote: We have a 93 beretta with a 2.2 and a getrag five speed that was bought to serve rallycross beater duty. We have ran it in SF and it was a blast but we decided to run one more race in SF and over the winter build it for MF. The reason for this is we have always been car guys that like goofing off out in the garage, not because we ever had illusions of being famous racecar drivers, and we feel it would be a more enjoyable experience with a more open set of rules for the car. Here are the constraints we are working in, we are very budget oriented, both for the monetary reasons but also because a beretta is never going to be a "fast" car no matter how much money you throw at it, so why throw good money after bad. We may spend a little more on things like a proper race seat because it could be transferred to a car better suited to racing in the future. Otherwise our plans are to see how much we can get accomplished on a small money outlay. So far our plans are to 1) Strip all unnecessary weight 2) Strut brace, probably home made 3) Skid plate 4) Port and polish 5) Cage, probably a simple four point. We have access to a bender and will make this ourselves 6) A decent seat with bolster support and harness, probably an expired set from a drag racer friend. 7) We kicked around the idea of welding the diff, is this a good or bad idea? This car doesn't have a title so it doesn't see any street time. So give me some guidance, what other good bang-for-the-buck improvements should we be looking into? My teammate and I have a combined 20 years experience as mechanics and are decent fabricators so nothing is off the table, so long as its cheap. If you were in our shoes what would you add to the list?

Just so you don't confuse people - 4-point is a rollbar, not a cage. Rollbar is fine for rallycross and won't add too much weight (I used one for years) and yeah, it's great for harness mounting! A full cage you're adding a lot more weight and it's pointless for rallycross (though it does stiffen the chassis considerably - is the Beretta a noodle, or is it a good chassis? I have no idea).

Also, if you get some correctly-sized and legit race seats, you could run fine with a seatbelt. Half the time at rallycross I'm too lazy to put my harness on and just use the seatbelt (yep, I still have it since stage cars have to be street legal!)). I'm locked into the seat just fine. With my seats, I could probably rallycross with no seatbelt at all and stay in the set quite well, lol.... Harness is more for crash/collision safety than for necessarily holding you into the seat (IMO). Just saying that you may want to try just a race seat + seatbelt alone before you spend time/money on a rollbar just so you can use harnesses.

In reply to irish44j:

You're misunderstanding what I mean by "switched on", I think. I don't mean not focusing, I mean not trying to get 100% out of the course.

On my latest incar, I noticed that I had time to scratch my nose! On the run where the fuel pump was dying so I was just puttering around.

Knurled wrote: In reply to irish44j: You're misunderstanding what I mean by "switched on", I think. I don't mean not focusing, I mean not trying to get 100% out of the course. On my latest incar, I noticed that I had time to scratch my nose! On the run where the fuel pump was dying so I was just puttering around.

It's funny you mention that, because my in car from Black River Stages there are multiple times when I scratch my nose, lol. But usually on straights where I'm going 80mph. I get what you mean, I just think it's a different kind of concentration. There are stage guys that shoot for 100% of the course. Those are the guys that either win or eat a tree, lol. I'd put NONACK in that category, perhaps :)

I like my car too much to push it 100% at stage. Also I can't afford to build another one haha....

You need to cage that RX7 and do some stage with it, Pete :)

gearheadmb wrote: In reply to FooBag: ... As for the cage, we want to use a harness ...

I thought about a full harness with a harness bar but went with a set of Schroth Rallye harnessbelts. DOT-legal four point restraint that bolts in to the manufacturer provided seat belt mount points. Basically, the shoulder belts tie together behind the seat and then get bolted to the rear seatbelt mounting hole. The lap portion bolts to the lower two mount points for the factory three-point. I use them with stock Neon seats and it's shaved at least a second off my average run.

irish44j wrote:

gearheadmb wrote:

Just so you don't confuse people - 4-point is a rollbar, not a cage. is the Beretta a noodle, or is it a good chassis? I have no idea).

Right, I mixed up my terminology, rollbar.

As far as the chassis goes, I guess I don't know, but when the Z26 package came out they would pull .92g's on the skidpad with early 90's street tires on the same chassis so it must be decent.

wae wrote:

gearheadmb wrote: In reply to FooBag: ... As for the cage, we want to use a harness ...

I thought about a full harness with a harness bar but went with a set of Schroth Rallye harnessbelts. DOT-legal four point restraint that bolts in to the manufacturer provided seat belt mount points. Basically, the shoulder belts tie together behind the seat and then get bolted to the rear seatbelt mounting hole. The lap portion bolts to the lower two mount points for the factory three-point. I use them with stock Neon seats and it's shaved at least a second off my average run.

I'm getting one of these for the Abarth next year, if I keep on doing track events. And for autocross of course. Now you give me the idea for Subarust... It's only money right, berkeley it I have a job.

gearheadmb wrote: In reply to rslifkin: Yeah, we need to do some research on what cars share the 5x100 bolt pattern we have and what would be a good junkyard option for wheels. I think subarus use that pattern, so I was hoping we could find some of those with good tires for what we are doing. Is wider always better for rallycross, or not?

• Non-STi Subaru's
• Mk4 (99-05) VW Golf and Jetta
• PT Cruiser's and some Neon's

That is just a start

5X100 list from Roadkill Customs