I haven't given up, but nothing is going well.
To elaborate: After gravity-bleeding the slave cylinder, it was still spongy at the top of the pedal. I had the wife sit in the driver's seat to help bleed it. Pump it a few times, hold, open the bleed valve for a few seconds and close it. Repeat. After 3 times she said the pedal felt pretty good. I decided to do one more for good measure. As she put the clutch in, it went bang. I knew what had happened. Immediately pulled the slave cylinder, and as I did, I heard the rod hit the bottom of the bellhousing.
I screwed around with magnets and string for an hour before giving up and drilling the above half-inch "inspection port". That's a giant neodymium magnet in the photo. After taking the photo, I looped some safety wire around the rod, tightened it, then manipulated the magnet to find the end of the rod and pull it through the hole.
Installing yet another slave cylinder, I spent some time feeling around to make *sure* it was centered in the divot in the clutch fork. This time the bleeding went successfully, and the clutch works correctly. So far.
I'll point out that designs where the slave cylinder is external and the clutch fork simply protrudes through the bellhousing are far more sane. Seriously, BMW, it doesn't have to be like this.
This whole project has been awfully humbling. I used to think I was pretty decent with a wrench, but the number of mistakes I've made here are insane, and this car is not at all forgiving of any of them. I don't even want to talk about how it's going with the oil leak.
Learning a new platform is always a challenge. Obviously it will pay dividends down the road if you keep the car. I'm sure irish44j had some early challenges but look at him now...the resident expert. We've all been there. I've wasted plenty of entry fees because I couldn't get a car to work in time. I've also gotten it sorted at the wire. Either way, you're learning the quirks and ironing them out which is a necessary evil regardless. And although your struggles are frustrating, at the same time they are wildly entertaining to follow and very informative. Best of luck!
For the first time in a year, the car moved under its own power! It made it to the gas station!
And back, even.
The alternator quit charging, but I have a spare, and that'll be easy, right? Right?
To do before loading on the trailer:
Pie in the sky goal: finish a rally.
V2U_03 said:Learning a new platform is always a challenge. Obviously it will pay dividends down the road if you keep the car. I'm sure irish44j had some early challenges but look at him now...the resident expert.
Hehe....I still make plenty of mistakes. But yeah, the more you learn now, the more you'll know when you have to fix something on stage, or by the side of the road, or whatever. It's extra hard building a car that was already built by someone else, since you don't know what mistakes THEY made. My project cars always start bone-stock (including the rally car), so at least I know who to blame when they break :)
irish44j (Forum Supporter) said:It's extra hard building a car that was already built by someone else, since you don't know what mistakes THEY made.
Yeah, I think this something that gets left out of the "buy your first rally car" advice. It's rough starting on a platform I know nothing about (I've never even sat in a BMW other than this one), that's been totally hacked up so I don't even know where I'm starting. I can definitely say I wouldn't have gotten this far without this group.
Not only do I not know the mistakes made building my car, I bought it from someone who'd raced it for 5 years without knowing much about it himself. I know nothing about the whims and decisions or goals of whoever built it. (Okay, I know that someone named "T. Crowley" built it, but know nothing about him other than his name.) I should find a copy of the SCCA rally rules so maybe I can understand some of the goals. For instance--I assume the fuel tank is replaced with a fuel cell because the rules required it?
Finally, I managed to start fixing things faster than I was breaking them this weekend.
First up, the alternator. The internet let me know that some E30s refuse to charge the alternator if the charge light wasn't working. There's some disagreement about what year that change was made, or if it was universal. My charge light wasn't working, but I was pretty sure that it's never worked. But not certain. I verified that with the ignition powered, I got 12V field/excitor voltage to the D+ terminal which is the thing that gets interrupted with a busted charge light.
With that in mind, I turned to the spare alternator from the second engine, but it subjectively looked worse than mine. It's also filthy. But mostly I reasoned that it was very likely that the failure was the voltage regulator, and I didn't want to condemn an entire alternator if the problem was just the voltage regulator. Here's the Bosch regulator that was on the unknown alternator:
The one in the car was not Bosch and the lettering was impossible to make out. I swapped this one in, and the alternator worked just fine. The charge light never comes on. Not sure if it's burned out or bypassed in some way. The aforementioned joys of a car with an unknown history.
I wanted to replace the 20 year old seats with modern containment seats. Irish44j's photos make me think it's maybe possible to fit an HTE-R XL in there, but it's not certain. My codriver is quite a bit smaller than me, and he claims he fits comfortably in an HTE-R 400. In fact, he had one that he'd purchased for a Pike's Peak car that didn't run this year, so he gave it to me to install it. So I set about installing this seat, and it gave me fits.
First, it's about an inch narrower than the seat I had. I'm unclear about the wisdom of mounting a seat with spacers and longer bolts (seems maybe bad), so I flipped around one of the seat brackets which took up right about the right amount of space. I still had a heck of a time getting it in there, I think the brackets are *slightly* too tight now, but I did, eventually, get it. For reasons that make no sense at all, the seat is now farther forward. This is apparently due to the new seat just sitting farther forward of the mounting points than the old one did, but looking at them doesn't look that way.
I really need to move the seat brackets after about 2 inches, but given that I was running out of time, I think this will work fine. I needed to move the fire extinguisher forward a bit, and Jack has less leg room now, but I could fit in there and he's shorter than me.
My harnesses went out of date in 2022, so I installed new Sabelt ones. I really like Crow harnesses because the material is soft and easily adjustable, but the SFI-only certification is a bit frustrating. And while you used to be able to send them back quite a few times for re-webbing for like $60, they will now only reweb them a single time. Which means only 4 years out of a set.
I'm loving the adjust-at-the-buckle 2" lap belts these have. Super easy to get the lap belt much tighter than with the standard pull-up 3" belts. The shoulder belts are pretty hard to adjust because they're so stiff, though.
I put the old co-driver seat in place of mine, because the cover on mine is torn and it made tech upset last time. If I and the car make it through this event, I'll figure out how to get a proper containment seat on my side, too.
I got the ugly new graphics badly installed. I worked really hard on the last decals, and I'm annoyed at having to replace them with uglier ones so I spent less time on it this time. Trimming the windshield banner carefully is hard, and the black hides mistakes way better than the white. Oh well.
I've driven about 60 miles and it seems good. I cranked the idle up too high (about 1,200rpm) to keep the oil pressure high enough at idle to not flip the fuel pump shutoff relay. This would be bad for a street car, but I think it's fine here. My impression is that the car is slower than it was with the old engine, but that could just be in my head. The new clutch is way stiffer than the old one, but it's also fine. My $30 ebay short shifter is working great and makes it easier to get it into 1-3-5 while belted in. I should probably get one of the tall ones and bend it a bit, but this is fine for now.
The rear lights (which they actually checked at tech last year) like to stop working. Removing and reinstalling the bulb fixes it for a little while. I decided to pull them all and spray them with contact cleaner hoping that they'd at least work long enough to get through tech this year. Of course, one of the tail lights disintegrated on removal. Drove to the auto parts store to acquire a replacement.
I also plugged the new inspection port on my transmission with a rubber plug.
Went ahead and loaded it on the trailer!
So if you ever need to re-bleed the clutch master/slave the way to do it with these is to crawl under the car, pop the slave out of the transmission and just cycle the push rod in and out, ignore the bleeder screw and the pedal. Doing this just pushes the fluid back and forth while the bubbles slowly make their way back up to the reservoir. Pop the slave back in the transmission and you should have a decent pedal although it might take a few pumps for the slave to self adjust out. At least that is the common method for the E28 but it's pretty much the same system.
Good luck at your event.
In reply to Berck :
There's so much knowledge out there for these old cars but finding it can be difficult.
I chased a transmission leak for a couple of years, it would be dry on the road, dry at an autocross and after 3 sessions on track there would be a puddle and dripping out the bellhousing. Transmission in and out, seals replaced etc. but no better. Lots of google time, no better. Finally I broadened my search and dropped the E28 part and there it was, the answer! M20 powered E30's use G260 transmission as well, when you brake HARD for long with a lot of rpm on the input shaft it essentially pumps fluid out the vent, that fluid being hot, thin and runny quickly runs down and forward into the bell housing at the slave cylinder and then reappears out the bottom leaving very little trace of where it originated. The fix, run a rubber hose up to the firewall from the vent, put a small filter on it and you're good to go as there is not enough pressure on the fluid to push it up that high. Common knowledge in the Spec E30 world, it's written right into their rulebook, not common knowledge in the E28 world. I did get very good at dropping the transmission though!
We're not starting last! We're starting second to last. I have a speed factor of 4! At what point is it a slowness factor?
Rally is Brutal
After Erin Kelly (who I didn’t know) died doing it last weekend, I’ve spent some time considering the risk/reward ratio for rally, and it’s unclear to me that the reward is worth the risk. I’ve spent even more time considering the effort/reward ratio, and the results are more confusing. I don’t want to tally the number of weekends I’ve spent in the garage since I bought this car, but it’s an awfully large number of them. Thanks to sneakattackrally.com, it’s pretty easy to tally the amount of time I’ve spent driving it on stage: slightly more than 2 hours.
There’s probably a reason that everyone I knew in rally before I started was in Formula Vee. It’s not particularly easy to campaign a Formula Vee around a track, but it’s super easy compared to rally. My co-driver, Jack, drives a Formula Vee much better than I do and has been co-driving for a long time. I’d never have gotten into it without him, and he conveniently failed to mention how ridiculously hard it is. I probably wouldn’t have paid any attention if he had, though. My crew chief, Dan, worked for Sterling Chase (aka the Frobell) has been crew for hire for Rally, Pike’s Peak Hill Climb, and Formula Vee for the past decade. Also a fellow Formula Vee racer was working a radio checkpoint as a volunteer, and I ran into a long time vintage racing volunteer working ATC. All of you are crazy.
Rally Colorado is centered around Rangely, CO which is a small oil and gas town that’s most of the way to Utah. It’s in the desert, and as we headed out for recce on Friday, I was struck at how it only takes a few miles from the town center until you lose mobile phone reception and you can safely say, “Yup, here I am in the middle of the nowhere.”
I’m not sure if the porta-potty on the side of a desolate road is a national symbol of rally, but it’s absolutely a beacon for Rally Colorado. It took us the entire day to day to write notes and do 2 passes on all 6 stages. I’m pretty confident about all my calls for 1,2 and 6. But any 3 might have been a 4, and any 4 might have been a 3 or a 5, and any 5 might have been a 4. Such decisions started pretty rough, got better as I got into a groove, and worse as I got tired. Jack questioned some of them, and unilaterally corrected the worst offenders. None of our notes from last year were of any use–either we did the stages the opposite direction, or they were completely new. I should probably try the tape on the steering wheel thing. We got through it with about half an hour to spare. Thankfully, Dan was able to take the car through tech for us, otherwise we’d never have finished.
I’m not sure about this whole 30mph recce speed limit. I was, at times, cruising along at 50mph only to have to pull over for folks doing recce in pickup trucks at speeds that were probably above my rally pace. I will say that doing the second pass a bit faster helps a lot to see if the notes are any good.
Taken on its face, recce is absurd. “What did you do today?” “We drove 150 miles on some godforsaken roads writing down a bad textual description of them. And then we drove another 150 miles across the same roads to validate that our textual descriptions were, in fact, bad.”
We headed off to Parc Exposé which was in the parking lot of the Rangely Automotive Museum, and which would have been a little more pleasant had there been any shade. A bunch of people said that they thought my car was awesome, or their favorite, or that they were rooting for me. Most of them were shocked to find out that the hood was concealing 1.8l of stock BMW fury.
After exposé, we were to parade up and then down (unless it was down and then up) Main Street on penalty of $100. I remembered to bring some candy for Jack to throw at the kids this time.
Day 1 started with Dragon’s Trail, 12 miles of tight turns, a ton of elevation gain and loss, and a few gnarly exposures without much in the way of big speed sections. I drove conservatively, trying to get the hang of processing the notes, the feel of the car, and remembering how this whole thing works from my whopping 2 previous stages of experience.
As we got to the section of gnarly switchbacks where a mistake meant rolling hundreds of feet down a mountain, I backed off from slow and was immediately passed by the only car who started behind me. He never should have been behind me, in a STI and with a ton of experience, but no ARA-relevant times so they put him at the back. Since there were only 24 entries, the organizers used a 2 minute gap for dust at all stages–this means that over about 8 minutes, this guy passed me after starting 2 minutes behind me.
And it was terrifying. I, of course, had no idea he was back there with the dust until he got next to me. I braked hard to let him by quickly as we both charged toward a pretty impressive void. As he passed me, he got seriously sideways and it looked like he was going to slide right off the mountain. Somehow he managed to keep the car on the road, and I came to a complete stop for 30 seconds or so because I couldn’t see anything. I have no idea how he successfully passed me, and I’m pretty annoyed at the organizers for having him start behind me, even after he’d asked to be moved up.
I was driving slowly, and the car is really slow on the big uphill sections. I was still pretty crushed to find out that I was more than a minute slower than lateness on the first stage. I felt bad for Jack, who’s co-driven for some fast drivers. I still cannot fathom what it’s like to drive that section at the 14:03 pace the leader managed. I did it that first time in 19:02. The Jetta in front of me was also just over lateness, but was still a minute faster than me!
Still, my first stage, I finished, didn’t crash, and the car didn’t break. I resolved to push harder. But, uhhh…. not on the next stage. Which was Cathedral–4 miles of terrifying exposures with a super slick silt-covered surface that might give you pause at tourist speeds.
While waiting for ATC on the next stage, we talked to the Subaru driver who passed us because, of course, his arrival time was still a minute ahead of ours. There was clearly no room to let him around between ATC and the start, so we decided that Jack would walk our timecard in ahead of him on our minute. Unfortunately, he misunderstood, and arrived early even for our minute and wound up with a penalty. I felt bad, but at least he started in front of us. I crawled through the next stage, and was not at all surprised that I was still slowest. By a lot. But at least I beat lateness, so I didn’t feel nearly as worthless.
The third stage, Presser, was a mile long, probably flat out for those with confidence. After the finish is a left 3 without a lot of grip and a huge drop-off on the outside. During recce, I told Jack to be sure to get my attention, because it would be all too easy to go straight off the mountain and wind up on top of the oil well at the bottom of the mountain. I’m scared of big speed on dirt (at 80mph, I just feel like keeping the car straight is too hard), so I knew this would be another big loser for me.
While waiting for the start behind the Subaru we’d let in front of us the stage before, a volunteer suddenly demanded that we pull into the shrubbery to let Sweep onto the course in front of us. Clearly not a good sign. After half an hour, we were cleared to transit the stage and warned that medical was on scene at the finish and go slowly.
As we crossed the finish, I told Jack that I didn’t see medical or any car off, and he wondered if they’d cleared it already. And then, as we came around that tight left we saw it, a green Jetta on its side at the bottom of the mountain, leaning up against the oil rig, surrounded by lots of people.
I felt terrible. I didn’t get a good look at it, but the car looked obliterated and it had dropped a long way at what must have been pretty high speed. It was pretty clear that they hadn’t gotten anyone out of it in half an hour, and that just seemed like it meant the worst. I remembered seeing on Facebook that the co-driver was super excited about getting a ride at her first rally. I wondered what it would mean for rally if we killed someone 2 weekends in a row. As we headed back to service, we passed a firetruck screaming out of town at full speed.
It put a pretty big damper on any excitement I might have felt at getting back to service for the first time in a rally. Dan checked over the car and couldn’t find anything wrong with it, so we headed back out. We had to drive the car out of service, but were instructed to leave there and walk back with an estimated hour delay while they got medical in position for the next stage after handling the incident.
The next 3 stages were a repeat of the first 3. Dragon’s Trail went slightly faster (I at least made the lateness minute), and I was starting to feel like I was getting in a groove. I drove like a grampa through Presser, basically coming to a stop at the flying finish. The remains of the Jetta was on its feet, its occupants having been transported the hospital.
There was supposed to be a second service, followed by another run through Dragon’s Trail, but the medical delay meant that was canceled. When we got back to the service park, Sterling (who’d been volunteered for Sweep after only having signed up for tech) informed us that the driver and co-driver were alive and were expected to be transferred to Grand Junction for care. The driver suffered multiple fractured vertebrae and the co-driver broke her pelvis, but both are expected to recover.
Much beer that night, a pretty good sleep, and we headed out for day 2.
The first transit greeted me with a terrible vibration starting around 40mph. It got worse until about 55mph, and disappeared by 65mph. It only did it under acceleration, so it was clear it was something in the drivetrain. Driveshaft, differential, or axles. I wanted to go back to service and figure it out–as a track driver, you don’t set out to drive at speed in a car that has something wrong. Jack said we could do that, and he’d be fine with that call, but thought I should understand that meant we’d be done with the rally. You can’t just go back, check stuff out and continue with a penalty.
So I decided to press on.
We started out with Earl’s Bad Day, which we ran last year in the opposite direction as Earl’s Revenge. It’s a bit less scary in this direction, but only a bit. I felt more comfortable in the car, pushed a bit harder, and Jack said he felt like I was doing a lot better as a driver. The car did not explode, though the vibration got worse. The second stage, Quest for Darwin, had a bunch of technical stuff with some super fast sections. I bailed around 85mph on the super fast stuff, because it was also covered with a bunch of super slick silt that just made it unpredictable.
There was some delay getting ready for the final stage. Something about the 0 car. I’m not sure if this true about rally in general, but at least with Rally Colorado the volunteers are terrible about communicating what’s actually going on. All we knew was a delay.
While waiting, we ran into a fellow Formula Vee driver who was spectating, which was completely unexpected. Lots of folks wanted to know about rallying an E30 and were super supportive, kind and encouraging. Spectators were gathered for the start, and you could see the first few stages. I made a mental note to drive the L1 in plain view sideways, albeit slow. As long as you’re sideways, kicking up dirt, and making a ton of noise, they can’t tell how slow you’re going, right?
I think I did a pretty good job of it, making good use of my hydro brake. The stage felt good, though the vibration had turned into full on clunking–it was clear some part of the drivetrain was hitting the underbody under power.
As we cruised through it, we came upon the completely destroyed Subaru of David Peretz and Cora Masson just sitting on its side We’d met Cora the night before–she was a first time co-driver with zero experience or training but a ton of energy and excitement. They were holding the OK sign and a tow strap.
I was last. I had absolutely nothing to lose. But this seemed like a crazy plan to me. “Is this a thing?” I asked Jack as I came to a stop. “Sure!” he said, like he did this every Tuesday. David hooked up the tow strap, and I tried to create as much of a lateral angle between my car and his, even though mostly the tow strap angle seemed like it’d just drag the car on its side at best. As the tow strap got tight, I gave it the beans as the mighty M42 spun the rear wheels and we inched forward. I watched in my rearview mirror as the Subaru amazingly tumbled on to its wheels like something in a movie, kicking out a giant cloud of dust as it landed. I reversed a bit for some tow strap slack, and David got us unhooked immediately and smacked the rear window to let us know we were good. The whole thing probably took less than 15 seconds.
As we got to the end of the stage, I told Jack, “That feels like the most rally thing I’ve done all day.” “No,” Jack said, “You drove a rally car all day. That’s way more rally.”
David and Cora passed us on the next transit while I was pulling off my helmet and getting a drink of water on the side of the road. They were producing a truly extraordinary amount of foul-smelling smoke, but they were moving under their own power!
We got to service, and Dan quickly diagnosed the problem as a trashed CSB. The rubber surrounding the bearing was non-existent, so the center of the driveshaft was just flailing around and smacking into the now-deformed metal that used to hold the rubber. He tried shoving some carefully-formed beer cans in there, but I don’t think it made any difference.
Additionally, the trunk latch seems to have lost the C clip that holds it closed, because BMW. Some zip ties to the rescue…
The final 3 stages were a repeat of the previous 3. At this point, it came to pass that I was 13th overall, and 2nd in class. Despite being the absolute slowest by a truly stupid amount of time. Jack pointed out that all I had to do to podium was finish. I had lost track of the number of upside down and destroyed cars that I’d passed on stage. My feeling at this point was a not-very-rally, “You know, if they didn’t drive so fast, maybe they’d finish.”
The second run of Earl’s Bad Day went great. The notes were on, the sun was behind some clouds, and it was like only 95 degrees. I was feeling good. We headed into Quest for Darwin with a, “let’s just finish,” resolve. The stage went great. We passed a disabled car on one of the fast sections, and I cautiously motored past.
And then we crashed. It was a right 4. It looked fine, I turned in, the turn tightened, I turned more, and nothing happened. I hit the brakes, and it felt like sped up as we smashed into the side of Colorado. It seemed like too hard a hit to continue from, and sure enough, the car wouldn’t go anywhere.
All I had to do was finish. So I crashed 100 yards from the finish of the penultimate stage.
Sweep dragged us closer to the finish where it’d be easier to get the car on the trailer.
Fortunately, my Formula Vee friend Jared who was working one of the radio points had enough phone service to get in touch with Joanna and Dan who came and got us. The top of the shock and the control arm were snapped. Getting it on the trailer was a ton of fun–we actually managed to balance the wheel assembly in place and brace it with ratchet straps and zip ties to winch it on.
Fixing this is going to suck. The wheel smashing into the fender well moved my dead pedal about six inches and ripped a hole in the sheet metal under the clutch. The hotbits strut is welded in to the knuckle, because BMW. I have to somehow cut the old one out, and weld a new one in. First, I have to find a new one, which you can’t just order on a website because hot bits is some random thing in Malaysia so I have to fill out a web form and figure out how to order it. Not that I know what to order, since the part number was scribbled on it in sharpie 20 years ago and isn’t legible now.
But, I guess I’ll order a welder and figure out how to fix things, because I’m not very good at doing the math on either effort/reward or risk/reward ratios.
Quest for Darwin (full video that leads to crash)
Cathedral (scary, so slow)
Sounds like a rally to me! Bummer you didn't make it, but that's part of the game- and yeah, it's ridiculously hard. Colorado is also not exactly known for being an easy event to finish.
I have a Hotbits contact who I think is still current, shoot me a PM and I'll send his info over. That said, I personally think I'd rather run Bilstein HDs than Hotbits.
I'm definitely open to opinions on suspension. As I bought it, the car is hotbits coilovers with separate rebound/compression adjustments and helper springs. I'm not married to the stuff, and my rough guess is that it's way too stiff for gravel, but I know nothing.
I can comfortably say the car the car feels to me like garbage on stage. But also I have no idea what it should feel like, since I have no experience on gravel or in an E30. It's nothing but it's a huge fight to get the car to turn in, and once it does, it's a whole bunch of oversteer. I suspect some of that is the welded diff which is going cause a bit of understeer on turn-in and oversteer on exit as long as I'm on the power. Also willing to admit that my driving skills are all optimized for formula car on a track. I did force myself into left foot braking this weekend, and some trail braking did wonders for turn-in when I got it right.
I see what Josh did on his E30 (a bunch of custom fabrication from Ford Econobox stuff), and I guess I'm not completely opposed to trying to duplicate that, but man that looks like a bunch of work. I'm on a different point in the money vs time curve, and at this point would rather spend some money to save me some time in the garage. I'm supposed to be building an airplane (which will save, I dunno, hundreds of thousands of dollars over buying a comparable one that's already built), and I want to get back to that while still rallying sometimes. If I can spend a couple thousand dollars to avoid a few weekends fabricating, that's a reasonable tradeoff for me.
I see no options to buy anything bolt-on for rally, and almost nothing for sale that's rally-focused at all. I could buy some stock E30 knuckles, put in some Billstein HDs and stock-ish springs pretty easily. My guess was that would be a step down from the hotbits, but maybe not? Given my ability and aspirations maybe this is the easy/cheap button.
I'm not seeing anything that gets me a coilover setup on the E30 with Billsteins except for this, and "contact your Billstein dealer and we'll fabricate you something in the UK" sounds time-consuming and super expensive? Unless I do what Josh did, and maybe the hardest part of what he did is just finding all the right parts and he already did that?
I have done the same 40mm stuff Josh used on a couple cars now, it works fine but does definitely require some welding. If you want to spend big money, I know Intrax can also make you E30 stuff.
That said, if you want the cheap and easy button, I'd do whatever was on Josh's car prior to his 40mm struts- which I think was some combination of off the shelf Bilsteins and springs from other BMW models.
It does sound to me like you're probably fighting the diff, I would try and acquire a normal clutch LSD and put it in there- welded diffs can work well on gravel, but if you're learning it's going to be a pretty bad time trying to get the car to rotate consistently. You really need to just chuck it in and ride the oversteer through or it'll feel like it doesn't want to turn.
Edit: Realized I didn't answer the "are Bilstein HDs a step down?" question. In my experience, street focused suspension is actually easier to drive at low speeds on rally stages. It'll run out of strength/damping/bumpstop/travel as you push faster, BUT the inverse of this is that most rally suspension I've driven on doesn't work very well below a certain speed and therefore feels like crap until you push it fast enough to actually make it work.
One of the weirdest things about the welded diff I used to have was that, on pavement, accelerating mid corner made it feel like someone had a rope on the nose of the car and yanked it to the inside of the corner. It was not that the back end stepped out, it was that the front turned in a lot harder. This was fun to exploit
On dirt it definitely understeered a lot under power, adding front stiffness helped a lot. YMMV of course. Loose surfaces work "backwards", at least for undriven axles increasing load transfer will increase, not decrease, grip. It's a balancing act, of course.
Pete. (l33t FS) said:On dirt it definitely understeered a lot under power, adding front stiffness helped a lot. YMMV of course. Loose surfaces work "backwards", at least for undriven axles increasing load transfer will increase, not decrease, grip. It's a balancing act, of course.
I disagree with this entirely and think it's probably specific to the chassis you were dealing with, or the rallycross environment you were using it in.
Okay, definitely very interesting realizing that the stiffer suspension doesn't work as well at slow speeds. This actually checks out--I will say that I had faster moments that felt way more under control than other much slower moments and I chalked it up exclusively to grip and luck, but it might make sense that this stiff suspension just isn't doing its thing until it's loaded up, but works much better once it is.
I'm also generally of the philosophy that I'd rather learn to drive what I have than spend a bunch of time setting up a car for a sub-optimal driving style and chasing my tail trying to learn to drive a moving target. So if it's possible to make the welded diff and hotbits stuff work well on this car on gravel, I'm happy stick with it until I figure it out. I'm not afraid of the oversteer (my Vee is setup for slight oversteer, and I like it that way), and if the answer really is that the way to drive this diff is to have some amount of oversteer around every corner I can do that--I was mostly assuming that driving that way was pretty slow and was trying to find a speed that didn't result in hanging it out on every corner.
On the other hand, if learning to drive it is just going to be a crashy nightmare, maybe finding an LSD is the better option.
I'm disinclined to the go the 40mm route--the 40mm E30 stuff is rare (only the early cars), and I note that you're breaking it regularly enough to consider upgrading yourself. I'm guessing my E30 is heavier.
In reply to Berck :
I do think the LSD will be easier to control in general, but if you want to drive the welded diff I'd remove the front swaybar if it has one and go for it- you're right that being super sideways all the time is slower, so it'll probably be a game of getting comfortable getting it to rotate and then dialing it back until you're straight on corner exit consistently.
In reply to ¯\_(ツ)_/¯ :
No front or rear swaybars here--car didn't come with them, and I don't even know where they used to mount:)
In reply to ¯\_(ツ)_/¯ :
It's worked on the front of rear drivers and the rear of front drivers I have had, so I will stick with it. As you say, suspension layout may play a factor as well.
I know on an RX-7 of any level of modification, removal of the front bar leads to wildly uncontrollable mid corner oversteer, since the rear suspension doesn't articulate much and when you unload the inside rear you lose grip easily. But up to that point it has the turn in of a cement truck. Same for a rear drive converted Subaru, which was probably one of the worst cars I have ever driven as far as having a small "bubble" to drive on mid corner is concerned. You were either nosing off into the woods or pirouetting, with a knife edge in between. Needed a front bar and more front spring and less rear spring.
It is an avenue worth investigating, at least.
I will say that once I get the rear to step out, I find the oversteer to currently be very controllable. I sometimes got more than I was aiming for, but it was very easy correct and I never spun. What I find unpredictable is whether the car will turn *at all* on corner entry. Stabbing the brake a bit to get the front to bite seems to help a bunch. Also, understeer on pavement is such that if a little steering input does nothing, more will do even less. This seems to be not the case on gravel--sometimes a little does nothing, but more will cause it to dig in.
Berck said:Stabbing the brake a bit to get the front to bite seems to help a bunch. Also, understeer on pavement is such that if a little steering input does nothing, more will do even less. This seems to be not the case on gravel--sometimes a little does nothing, but more will cause it to dig in.
First part is a big yes, especially if you've got the brake bias right- you can also come in hard on the brakes and the car will start rotating a bit on its' own, and you use that.
The second part about adding steering input helping can depend on the surface and density of gravel/dirt, I wouldn't count on it- I'd focus more on how the brakes help the car turn.
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