Rally Car tear down thread!
 

So i completed my 2nd rally last weekend. Prescott, AZ Rally ! it was 5 coefficients over 2 days of pure awesomeness!


I'm still on stock suspension, only protection my car has is a Primitive skid plate :cool:

Amazingly all i did was Dent up some rims (quite a bit, damn steelies) My crew pounded them out @ service and sent me out, then did the same thing the next day at service. I also managed to pull apart the headers. :lol: It has a "rolled fitting" where basically they take pipe A with an OD of 2.02 and pipe B with an ID of 2.00 and force A into B. no welding or anything it just stays. unless you rally on stock suspension and you only touch the brakes for 120 ! dip 50 !dip (think i slowed down to maybe 60! hahaha)

anywho I'll take some photos later on of the header fun, and skid plate 'wear' :lol: . Oh and i tore up the lower skid plate bolts big time. I'll have to cut them off with a grinder / cutting wheel later on this week.


But wow, Subarus are just amazing. 1993 Impreza, Driven to work , Only saftey mods done, and it just rocks @ rally. Think i got 4th out of 7 in USRC Prod 2WD, and 4th out of 5 for Performance Stock. not too bad for a noobie, i even stopped, backed up , and pulled a competitor off a berm. which was fun, though it was at least a full 50 seconds of me not racing (have in car of it)

I really need to get rally suspension and a LSD.
From my lil bit of research the only USDM subarus to get a Front LSD are the STIs, and maybe some 05-07 WRXs? I'm thinking of getting a Helical front diff , as i need to be able to drive it on the streets, i drive down 3 hours to some rally crosses, not to mention some Rally transits can be very long (had one of 38 miles that would be similar to driving up an down to Virginia city)

am i missing any models that might have a front LSD i can just pull out?

Congrats on the event. Just finishing is an accomplishment, let alone not being DFL.

Off hand, I don't think Subaru was ever big on front LSDs. You're probably looking at an aftermarket diff, as I'm not so sure that an STi diff is a good idea in a FWD car simply because it was designed specifically to work with the other two diffs in the STi. Sure, it would probably be an improvement over an open diff, but you'll probably be spending a pretty penny to get one, in which case you can probably get a Cusco diff tailored for what you're doing for not much more. And if the STi LSD can't hold up under FWD rally conditions, well now you're not just spinning the inside tire, you're DNFing. :(

You might want to get in touch with the RalliSpec guys, or Jamie (SubieGal on NASIOC), they can probably point you in the right direction... just don't let KevinM know you're talking to SubieGal.

Thanks, Wow i had just started hitting up the RalliSpec guys, they seem to know a lot about Diffs.

http://www.youtube.com/watch?v=ymHimE_ZfoA Stage 2, got it off my camera . I'm itching to upload stage 3, as i pulled out someone off the berm. (it was more exciting then it sounds) hehe

I'm pretty sure the AWD front diffs aren't compatible with the FWD gearbox, so there may literally be no LSDs available for you other than the Phantom Grip thing.

Yep , for USDM it seems that only the STI gets a LSD in the front.

Phantom grip, Quaiffe and this Subaru helical :
http://www.rallispec.com/prod_diff.htm
which i'm guessing may be from JDM cars ?

I'm leaning heavily towards a Helical as they are more street friendly and less maintenance (or known if the ad is correct)

I believe the old S^2 DSM rally car just did a welded front diff.

You're in a rally car, who needs a differential? Solid front axle for the win! In all seriousness, its not as likely to break and its much cheaper than an LSD. Its probably not the best option out there, but I figured I'd throw it out there. You might want to see what the other RA/NASA rally guys do for their FWD cars.

Except he doesn't tow to/from the event and has tarmac transit stages. A welded diff would be messy on the street... you'd plow off the road all the time! :lol:

Only problem with a spool is that you'll start popping CV's on pavement if you've got a lot of traction; the diff can't unload, so if it can't spin the inside or outside tire, the bearing cages start taking the abuse. But, like Nick said, it's the way to go, especially on a transmission you don't want to be popping open to adjust all the time. Phantom grips are hit or miss, but if there's a fitment for it, I'd grab another diff, build it with the PG, and see how you like it; then you have a second (spare) diff out of the car that you can weld. Spools also start wearing the rest of the transmission on FWD cars, because you're transferring all those loads both ways, back to the input shaft, etc. The Legacy Turbo I had that was RWD didn't blow up its spooled rear, it went through so much shock loading the pinion/input shaft started wearing as well as the input shaft bearings, giving it so much slop it was leaking out the front of the diff, lol. If you've got a spare tranny, it's no big deal, but I figure you're not trying to throw a parts budget bigger than the car at transmission parts in the short term.

FWD axles should be cheap; keeping a couple of spares (hell, 2 full sets is only going to be around $250-300 from Napa, etc) is going to be your best way to go, with either setup.

Details details.

We also would have accepted: "That's what a hydro turning brake is for, you wuss."

or "That's what the e-brake is for!"

I have 1 spare tranny. The transmission in the car requires that i use 93 FWD only half shafts, the FWD transmission made in 94 (many sold in 95) has the splines for the same half shaft that goes into a wrx. knuckles use the same splines too) actually i think almost all of the subaru half shafts past 95 have the same splines (both at the knuckle and where they mount to the tranny)

my 94 tranny requires a different clutch kit, i haven't bought the parts yet.

Napa will sell you a half shaft for $50 with a core charge. you can get a used half shaft for 20, 25$ on a 1/2 off pick and pull day. so that's like 75$ , and in some cases you get a brand new half shaft (last one i got from napa was BRAND New, but boxed as refurb)

Rallynotes uses a phantom grip LSD. they seem to have great success. not sure what Beavis , or the Masano father and son team was using. Max masano mentioned that after he added a LSD that getting on the gas mid corner helped the car claw through the corner. where as i more get the feeling of throttle understeer.

Welded is possible , cheap, i have the needed parts, but driving transits would be horrible. (200 miles at the last rally, and my crew had to use the car to buy some last minute parts)

some type of tunable Plates would rock, although I want to keep the maintenance down .

I'm heavily leaning towards a Helical , but i'm not going to jump into any purchases any time soon.

How quickly are coil overs going to wear out (ie struts need rebuilding) doing some high way driving. say like 200 miles a week, @ speed limit, gentle corners (no tire chirping) :?:

Or if i plan to do 5 rallies a year, would 6,000 comuting miles have a noticible impact on the coil overs performance?

I bet 6000 hwy miles would be a drop in the bucket compared to what 5 rallies would do to the coilovers.

Get something BEEFY unless you plan to rebuild them more than once per season. Also keep in mind the need for spares... spare stock struts are easy... spare DMS or Ohlin rally coilovers require a second mortgage.