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Discussion Starter #1 (Edited)
I posted in the "introduce yourself" thread a few months back and havent posted since. Figured I would share the "build" of my e36. Hopefully this is the right forum.

Purchased this '93 BMW 325is for practically nothing in june of last year. 220k miles, interior was trashed. Engine ran strong, transmission shifted smooth, LSD worked, drove it home 90+ miles.

This is a very low budget build as I love rally but cannot afford to buy/build a proper car. I have a garage full of metal fabricating tools and this is what I can do for now, and I have a blast doing it.

When I bought it:


While playing around on the dirt roads by my house two days after I got it, I caught a berm and ripped the bumper off, so I fabricated this:



I threw some steel wheels on it and took it rallycrossing. I go to the az rally group events held in tucson. First event was in July, I placed dead last in my class. Second event was in September, I did much better, 4th in class behind 3 guys driving the same ford focus. Not enough entries to separate fwd and rwd.

Heres a video I made from the second event. Blown out struts spewing fluid, crappy all season tires, fun times.

After that event, new struts were put on, and I built a skidplate from bumper to engine crossmember, then from engine crossmember to body crossmember.



 

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Discussion Starter #2
I competed in the November rallycross and placed 4th again, behind the same guys in the focus.





While at that event I picked up some used winterforce tires from a fellow rallycrosser that are a size too big. I made them work with a little "inspiration" from the big hammer and a grinder when I got home.



After that event I replaced a good chunk of the front end suspension, balljoints and control arms, bushings, swaybar ends, tie rod ends... I also began to gut the interior.

 

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Discussion Starter #3
Which brings us up to date.

I finished gutting the carpet and in the process broke the plastic doodads that hold the center console around the shifter in place. So I had this mess to deal with



Thats all the wiring from the onboard computer, heated seat switches, window switches, etc. I know I can get rid of a lot of it, but I'm a little scared to start yanking wires. So for now it stays. However i didnt feel like staring at it, so I picked up a small panel of sheet metal today and made this:





Overall Im happy with the fit, but the flasher switch hole turned out crappy, needs some cleaning up and some sort of gasket or something around it, it jiggles around. Also I only had two switches, thus the empty hole. Can't decide whether to do a better job grinding it and leave it bare, or give it some krylon.

Next rallycross event is Feb 15th. I will be competing in modified 2wd this time around. They even used my car in the promo flyer for the series!

 

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I like your car-looks like fun!

What size tires?

They look awfully large...

It's great you are getting seat time and will most likely improve your scores as you gain experience,but don't underestimate how much performance can be sapped by tires that are too large.

Not only too heavy,but too tall diameter can kill your gearing....
 

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Discussion Starter #5
I like your car-looks like fun!

What size tires?

They look awfully large...

It's great you are getting seat time and will most likely improve your scores as you gain experience,but don't underestimate how much performance can be sapped by tires that are too large.

Not only too heavy,but too tall diameter can kill your gearing....
Yeah, I got them for $50 for all four, I figure it was worth it to experiment. I do know the all seasons weren't cutting it, and these came up for cheap.

Stock tire size on this car is 205/60r15, around 24.75" diameter. These are 215/70r15, just under 27". I will see how they do in a few weeks, I have driven it around town and some dirt roads, and while I could tell a difference, it wasn't huge. Gearing is pretty low stock in the 325is. One of the guys I compete with drives a e30 running general grabbers in the same size and seems to do pretty well. I will definitely update after the event in feb.

Thanks for the response too.
 

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Yeah, I got them for $50 for all four, I figure it was worth it to experiment. I do know the all seasons weren't cutting it, and these came up for cheap.

Stock tire size on this car is 205/60r15, around 24.75" diameter. These are 215/70r15, just under 27". I will see how they do in a few weeks, I have driven it around town and some dirt roads, and while I could tell a difference, it wasn't huge. Gearing is pretty low stock in the 325is. One of the guys I compete with drives a e30 running general grabbers in the same size and seems to do pretty well. I will definitely update after the event in feb.

Thanks for the response too.
pretty low?
Back axle on the chart I looked at says its like 3.15:1 ... That sky HIGH. Big 27" tires going to make it like its 2.85....even higher.
"Low" is like my old stock Saab at 4.88:1

Maybe iit makes no difference but its the wrong way to wake up a car and have more fun to bump gearing HIGHER

(think of the trans...first gear is sometimes called "low" or when its 4.25 like a pick up its "granny low". 5th is "top gear" or "high gear")

Are there any bumps at all where you go play around? Those things are notoriously short on travel in front...less than 140mm total travel.
YIKES!
 

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Discussion Starter #8 (Edited)
I understand how tire size affects gearing. As I said, this is a verrrrrrryyy low budget rallyx car. As in, I don't even have $1500 in it as she sits now. The traction increase to gearing loss on the relatively low speed courses we run should wash out. And if they end up making the car too sluggish, then I can pass them on to someone else.

I am not building a competitive racecar... Yet :cool:
 

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Discussion Starter #11
Last weekend was the first rallyx of the year for the AZ rally group.

I drove AWFUL, but I had a blast. My buddy and brother in law both went and drove my car as well. The way the run groups worked out one of us got to drive in the first run group, and my buddy jumped in and took second in our class behind this beautiful fully prepped MG:



Driving in the first run group was a huge advantage. Very few ruts, a smooth graded surface, etc. By the time the second run group got out there it was blown out pretty good. Plus they decided to run the water truck pretty heavily between groups, so our first 2 laps were a swamp. The tires grabbed much better than even I thought they would. I had been working like a madman the last few weeks, and working on various things on the car, which led to not much chance to get out and actually DRIVE the car, so I was over-steering a lot. One massive oversteer in a tough section led to an off course donut on lap one. Fun times ;)





While I personally drove terrible, I think overall the suspension and tires are a huge upgrade over the last event. There was definitely a noticeable difference in the gearing, so I am going to be on the lookout for something a little smaller in the same tread style. It was fun to drive but I had to downshift a lot, and never got out of second.

Lucas Oil and a local Subie dealership provided prizes for the winners, first time this region has had anything other than plastic trophies. Pretty sweet.

Tons of photos from the event here if anyone is interested.
 

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In case you are interested, we are running the following spring rates on our E36 rally car:
350 lb front
150 lb rear
This is with rally-valved Bilstein inserts.
Good luck with it!
Dave
 

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Coilovers with Sellholm strut bodies and Bilstein inserts. Not sure of the valving, but I asked Rikard at Sellholm to use Rally-GB-like valving.
 

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Bump!! I'm getting ready to build an E36 M3 sedan into a rally-x car, and I wanted to bounce suspension ideas off some of you guys. The spring rates that both of the Dave's mentioned seem to be very different from normal E36 rates. Are those rates calculated at the wheel taking into account the motion ratio, or are they straight spring rates? All other E36s (granted, they are street cars) seem to run rates roughly 100 to 150 higher in the rear than fronts, but both of the Dave's run much higher rates in the front. Can you explain how you guys came to those rates? Are they more tailored to real rally, or for rally-x? After taking to some knowledgeable E36 people, I seem to think that something like 250f/350r would be a good setup, but after reading your rates, I'm reconsidering. Stock rates for the M3 is somewhere between 105f/335r to 100f/240r to 120f/335r, depending on who you ask and how you measure it.

I'm currently taking with the guys at Ground Control, who recommended a 500f/600r setup with 8" springs all around. I also talked to the guys at Rogue Engineering, who said they might be able to make a TC Klein setup work. I then called up Bilstein directly and they said they could also put something custom that would work, but they weren't sure about how to set up the spring rates and lengths.

Another issue is whether to use progressive or linear springs. A bunch of the E30 guys I run with swear that linear springs in the back make the car much more settled compared to progressive, but I can't help but think that the softer initial travel of the progressive springs would help keep the wheels on the ground better.

I'll post up more complete thoughts later, but I wanted to get the discussion started!
 

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My springs are out at the hub in a coilover mount. Keeping the springs in the OEM location means you'd need a much stiffer spring to equal the 200# spring I'm using.

On a traditional E36 (meaning NOT a compact), I believe you want to try to keep the spring in the stock location. This saves the knuckle from taking all the forces during a big hit. Brandenburg, Hintz, and possibly Nelson have all had failures at the shock mounting point when running coilovers.

My JVABS, Ohlins, and others all use linear springs, so I don't see any reason to reinvent the wheel (or add more complication) by messing with progressive springs. I'd bet with progressives, you'd just eat up a bunch of travel easy and be more prone to bottoming out. Unless you lift the car a bunch, there isn't that much bump travel on these cars.

My $0.02, stop messing around by talking with shops that do primarily road race and street car setup. If you want to keep it on the cheap side of sturdy enough, give JVAB a call, he's built me both 40mm and 50mm bilstein stuff. Not sure what current costs are, but I thought prices were very reasonable for what you get.

Dave
 

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My $0.02, stop messing around by talking with shops that do primarily road race and street car setup.
Copied for emphasis. Those guys have NO clue on what will work on gravel. Most have no clue what will work outside of a parking lot. Many others are simply repeating or mildly modifying what they heard from the few that were road racing but often trying to find a cheaper setup to poorly mimic a proper one.

If you are just doing rallycross, just stick with stock springs and Bilstein replacement struts for now. Isn't the M3 slightly shorter so maybe get the base 325i or 328i setup, but make sure to use the M3 top mount. The Bilstein HDs are a little stiffer but also a little pricier.
Spending more money will just be spending more money. Stock stuff will perform better at rallycross, still performs more than sufficient on street, you'll save money, and you don't have to deal with the harsh ride.

Sometimes cheaper products that mimic a nicer product are just a cheaper product that will cost you more in long run. Eg. Hot Bits or K-Sport.
 

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My springs are out at the hub in a coilover mount. Keeping the springs in the OEM location means you'd need a much stiffer spring to equal the 200# spring I'm using.

On a traditional E36 (meaning NOT a compact), I believe you want to try to keep the spring in the stock location. This saves the knuckle from taking all the forces during a big hit. Brandenburg, Hintz, and possibly Nelson have all had failures at the shock mounting point when running coilovers.

My JVABS, Ohlins, and others all use linear springs, so I don't see any reason to reinvent the wheel (or add more complication) by messing with progressive springs. I'd bet with progressives, you'd just eat up a bunch of travel easy and be more prone to bottoming out. Unless you lift the car a bunch, there isn't that much bump travel on these cars.

My $0.02, stop messing around by talking with shops that do primarily road race and street car setup. If you want to keep it on the cheap side of sturdy enough, give JVAB a call, he's built me both 40mm and 50mm bilstein stuff. Not sure what current costs are, but I thought prices were very reasonable for what you get.

Dave
Thank you! When you talked about keeping the springs in the stock location, I assume you were referring to the rear? I did a quick search of JVAB and the website didn't really inspire confidence. What's the best way to get in touch with them? Were those guys with the failures doing real rally stuff with jumps?


granthughes said:
Copied for emphasis. Those guys have NO clue on what will work on gravel. Most have no clue what will work outside of a parking lot. Many others are simply repeating or mildly modifying what they heard from the few that were road racing but often trying to find a cheaper setup to poorly mimic a proper one.

If you are just doing rallycross, just stick with stock springs and Bilstein replacement struts for now. Isn't the M3 slightly shorter so maybe get the base 325i or 328i setup, but make sure to use the M3 top mount. The Bilstein HDs are a little stiffer but also a little pricier.
Spending more money will just be spending more money. Stock stuff will perform better at rallycross, still performs more than sufficient on street, you'll save money, and you don't have to deal with the harsh ride.

Sometimes cheaper products that mimic a nicer product are just a cheaper product that will cost you more in long run. Eg. Hot Bits or K-Sport.
Unfortunately the M3 uses different sized springs than the non-M cars, so I can't just install their stock springs. Even at stock height, I'm pretty sure the M3 is way too low. I feel like coilovers are the only way for me to get a little height back, but I'm now wary after reading that they can cause the shock mounting point to fail. What else can I do to raise the car up a bit? Throw on some rubber spring spacers like I did on my E28?

I spoke with a guy from BW about setting up a Ground Control/Koni setup for me. He said I can spec it with stock length (not shortened for lowered cars) Konis, 8" f/7" r springs, 250f/350r. Total cost would be something like $1100. It seems pretty reasonable to me, but I've never built rally coilovers before. My main competitor in a 318 E30 just converted from stock style H&Rs to a GC setup, and he loves it.

Let me pose one more question to you guys: generally speaking, where do you fall on the OEM/rubber bushings vs. poly vs. delrin, etc on a rally car? The more I read and hear about Powerflex and other poly bushings is that they can crack easily and break apart. After putting delrin on my street car previously, I'm pretty sure I don't want that anywhere near my rally car. I feel like some new/upgraded rubber bushings throughout the car would do a much better job of keeping the real tough stuff from being so abusive to the body of the car, and I would rather replace a rubber bushings than deal with ripped or bent sheet metal. Are there any mounts that you feel should get special treatment?
 

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I have a huge aversion to talking to made-up-names, it seems childish and immature that we should be TRYING to discuss something expensive and important but "wearing" a mask and hiding ostentatiously a name, still though 95max.

What you read about coilovers damaging mounts is wrong....
The thing that generates a lot of force--and thus stress on a shock mounting point is the degreee of resistance that the valving in the shock generates..
Especially on the compression dampening side should somebody chopose to valve it overly stiff as most everybody does.

The spring does not multiply or increase the force it is resisting--and in any case, its just a couple of hundred pounds per inch of force..Nothing for a M10 or a M12 bolt.
But the damper can generate up to virtually infinite force if valving is wrong, design of adjusters dis-allows sufficeient pass thru on sqaue edge bumps causing what's called spiking...

All this little subtle details escapes those who, despite probably never seeing inside one actual shock, go around on every forum speaking loudly, confidently, and wrong.

And I bet they have race careers at least 3-4 hours long....(on one forum I occasionally look in on the self described "experts" who incidentally say the same BS about adding a 175 in pound spring will snap off mountts and ruin bodyshells brag about "In my racing experience...which is 100% in parking lots in maybe secondd gear for a minute and change at a time and totals perhaps 3 or 4 hours total in his life in a mainly stock--aside from his disasterous choices in springs-car.
It would be funny if it were no so sad that he advises street/road guys to use springs---with ordinary out of the box KYB or Koni--that were more than 60% stiffer in front than the manufacturer did in WRC with the same basic car, and more than double and a half stiff on the rear than the manufacturer used on tarmac in the WRC. Maddnaess.---But I bet you would feel confidence to read his website...
 

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I have a huge aversion to talking to made-up-names, it seems childish and immature that we should be TRYING to discuss something expensive and important but "wearing" a mask and hiding ostentatiously a name, still though 95max.

What you read about coilovers damaging mounts is wrong....
The thing that generates a lot of force--and thus stress on a shock mounting point is the degreee of resistance that the valving in the shock generates..
Especially on the compression dampening side should somebody chopose to valve it overly stiff as most everybody does.

The spring does not multiply or increase the force it is resisting--and in any case, its just a couple of hundred pounds per inch of force..Nothing for a M10 or a M12 bolt.
But the damper can generate up to virtually infinite force if valving is wrong, design of adjusters dis-allows sufficeient pass thru on sqaue edge bumps causing what's called spiking...

All this little subtle details escapes those who, despite probably never seeing inside one actual shock, go around on every forum speaking loudly, confidently, and wrong.

And I bet they have race careers at least 3-4 hours long....(on one forum I occasionally look in on the self described "experts" who incidentally say the same BS about adding a 175 in pound spring will snap off mountts and ruin bodyshells brag about "In my racing experience...which is 100% in parking lots in maybe secondd gear for a minute and change at a time and totals perhaps 3 or 4 hours total in his life in a mainly stock--aside from his disasterous choices in springs-car.
It would be funny if it were no so sad that he advises street/road guys to use springs---with ordinary out of the box KYB or Koni--that were more than 60% stiffer in front than the manufacturer did in WRC with the same basic car, and more than double and a half stiff on the rear than the manufacturer used on tarmac in the WRC. Maddnaess.---But I bet you would feel confidence to read his website...
Hi John, thanks for chiming in, but I must be missing something because I really don't understand what you're hinting at with your first sentence. I take it you are JVAB? What kind of spring rates would you recommend on an E36 running a coilover setup? Do you build setups for sale? Where do you fall on the rubber vs. poly bushing spectrum?

Edit: I took the hint and added my name to my signature. The reason I go by 95maxrider is because this is the name I chose when first joining a Maxima forum back in 2001 as a teenager, and although I sold my 95 Maxima way back in 2003, I still go by the name across multiple forums for simplicity's sake. I'm sorry to have offended you with my remark about your website, but when I viewed it last night, it didn't really load on my home computer, but it seems to be working fine here at work.
 
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