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 Post subject: Re: New member intro
PostPosted: December 14, 2015, 9:25 pm 
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I watch my coolant tank, but have never had an issue. I did have a valve cover leak, but that was a pretty easy fix. Never had any issues with my headgasket. Seems like it entirely depends on your luck. Some people seem to have everything go wrong; others like me never really have much of an issue. I haven't noticed much of a change in travel, but it has always been the first inch off the floor where all the engagement happens.

I'll tell you the only reason that most people run poly: you don't need a press to get them in. Most people haven't even driven a car with all fresh OEM rubber. The ride is tight but compliant. Poly has horrible impact harshness in comparison and I found that the Poly RTABS in particular and the binding they intentionally create in the rear trailing arm, created a far less progressive rear break away at the limit. I believe this to be the "snap oversteer" all the kiddos refer to when they wreck their cars.


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 Post subject: Re: New member intro
PostPosted: December 14, 2015, 9:42 pm 
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its kind of scary - funny - scary how many videos come up when you search "m3 snap oversteer" in youtube

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 Post subject: Re: New member intro
PostPosted: December 14, 2015, 10:31 pm 
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1055 wrote:
its kind of scary - funny - scary how many videos come up when you search "m3 snap oversteer" in youtube


Yeah. It's a huge problem. Many cars have been sent to the grave. The various forums are downright depressing! I noticed a very big change with the poly RTABs on my car. I didn't get any faster, the break-away was way less progressive and made it scary to push the edge, and then I got slower. I don't think they are a good solution if you're serious about going fast. Poly RTABs also increase the occurrence of the rear trailing arm pockets tearing out. OEM rubber for street cars, or spherical bearings for track use are my recommendation. The LCABs were much less dramatic in their handling alteration, but they just made things harsher and I didn't really feel like the steering was much better for it. I should preface this with the fact that I never ran slicks or oversized tires (only 235-40-17 in sticky street rubber), so I didn't have massive grip deflecting the LCABs. I think there is a good chance that poly LCABs would make a decent solution for handling big slicks and unlike the RTABs, the LCAB is a decent place (designwise, no binding caused) to use polyurethane. Oh and did I mention that they squeak after a while and you need to disassemble and re-grease it all? It took less than 3k miles and a couple snowy days for that charming trait to rear its ugly head. OH and the car developed a significant number of new rattles which went away when I took the poly off.

I replace my LCABS and RTABS every 40k miles. They cost ~35 a set (~70 for front and back). It's not a significant cost and it keeps the car handling like it should.

Advice I would give to someone just about to rebuild their suspension. Don't do the rear subframe bushings! I pulled my subframe at 130k and the bushings had no cracks and no visible damage. They were really difficult to remove even with a press and it took hours to get them out. Save the money, aggravation, and time and spend the money on something better, like good shocks.

I'd also recommend an x-brace, and a front tower brace (of good design). They do make a significant difference. The rear tower brace, on the other hand, does nothing.

If you've driven a plain E36 and liked it, then the M3 will be similar with a bit more of everything. I've also been able to push my M3 consistently up to 30mpg on highway, and my record on a tank of gas is 42mpg. A typical mixed driving tank yields 25mpg. When I flog it on the street I'm at 19mpg. If your mileage sucks, it's your driving or a good sign the engine needs some love.

Reading this over I realize I'm kinda harping on the poly thing. Guess I'm still sore after all these years that I paid the extra money for poly and it felt like I'd made the car worse.


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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 12:40 am 
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I believe this to be the "snap oversteer" all the kiddos refer to when they wreck their cars.


Dating myself here, but the only BMW I drove on a track was the old 2002. It had trailing throttle oversteer because the trailing arms made the wheels toe out when you let off the gas. You get in trouble because if you're going a little faster than usual for a turn and you need to slow down a little more than usual and you're a little later than usual then you're combining more turning and braking so you get more oversteer - it kind of adds up at the worst time and then your doing circles down the track.

It's actually those cars that cause me to encourage not having bump steer on the rear suspension. I think you would get the same behavior from older 911 and 240Z etc.

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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 12:54 am 
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The E30 has a very similar setup to the 2002. The E36 has a much better geometry that is much more predictable.

E36:
Image

E30 and older:
Image

E36 does not rear bumpsteer or have any trailing throttle excitement of note. I believe the "snap oversteer" is often pure old fashioned bad driving, where they come in too hot, understeer and scrub enough speed to regrip, and the car is flung back into the turn with all the weight off the rear tires and the front tires still turned.


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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 12:06 pm 
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It's nice seeing the E36 suspension compared to the older version that I'm much more familiar with. Thanks.

1055 - Just to clarify, by external HG leak, you literally mean that the coolant leaks out onto the block rather than into the oil? And with the coolant tank, does the plastic unit just end up cracking/leaking or what is the issue with them?

esp - It just occurred to me that the point you made about people not knowing how good fresh stock bushings are so they go for poly. In the E28 crowd, I'd say the majority "upgrade" (I added the " just for you and your frustration) to poly and it surely would be better than their 15-20 year old OEM bushings but may not equal fresh stock components (They may also just be better on the E28/E30/etc, because of the older design, who knows). Great point nonetheless. I also know your frustration with the noise and having to re-grease. I had poly bushings on the rear sway bar on my Mini and re-greasing the bushings was part of my yearly spring routine after dealing with a winter of rattling. It made me crazy. :BH:


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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 12:41 pm 
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In many locations, poly works great. I'm against it for specific applications. In the E30 and older design, the bushings rotate in a single plane if you will. This is a mode of operation that poly can operate well in: you have poly sliding for normal rotation. The E36 design for the trailing arm has them rotating in two planes. People associate "slop" at the rear end as the RTABs deflecting sideways, and so they move to poly or spacers around the bushing to limit the deflection. This stops the bushing from rotating in that second plane as the trailing arm swings through it's normal motion. It creates binding, and tremendous forces on the mounting pocket in the frame as the rotation works to compress the poly.

HG problems take both forms, depending on other conditions. A common occurrence is that the coolant tank cracks. It seemed that the result if the driver is not attentive is that they keep driving and significant coolant is lost, the engine overheats and blows a headgasket.


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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 12:43 pm 
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Yes - to both. The plastic coolant expansion tank will (not if, but when) develop a crack. Since its a pressurized expansion tank, when that crack fails.. it typically results in you puking coolant all over the highway and waiting for a tow. I checked my e39 528i tank at every oil change and it still wasn't enough. Saw no evidence of a crack, then the bottom blew out on I95 leaving NYC. I only noticed it happened when the temp gauge started skyrocketing. By the time I pulled over (Maybe 1/8th of a mile after the gauge starting rising past normal) it was too late. The block was basically dry. It warped the head and put a nice split right down one of the cylinder walls. Extreme case scenario here, of course.. but all in it was probably 2 minutes from blow out (literally opened the end like a tuna can) to engine boinked.

As far as the headgasket - I've seen on multiple occasions coolant leaks develop from the rear of the headgasket externally on the motor. It likes to pool then drip onto the exhaust manifold giving it that sweet sweet candy smell.

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 Post subject: Re: New member intro
PostPosted: December 15, 2015, 1:01 pm 
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1055, that is the tale that is told often. Seems like you either get lucky or not on the trashed engine. Sorry you got the short end of the stick. When I replace my tank and radiator, it will be with a good aluminum unit, there just hasn't been a call for it yet.

I pop my hood before every startup and poke around. Check fluid levels, at least visually check all tires. Most people comment on it like I'm crazy, but I view it as cheap insurance. More than once a tire has been low. If I was your typical hop in and drive off sort, it could have resulted in a crash.


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 Post subject: Re: New member intro
PostPosted: December 16, 2015, 12:08 pm 
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Thanks again guys, this has been fantastic! This has got to be one of the most welcoming forums I've ever joined.

Not sure where I'm going to be headed with this next car but I'll definitely be sticking around (although probably lurking). I would say that I'll start a very long "build thread" to begin talking about/through my mid-engined turbo M30 dream, but it seems someone has already started a thread about putting a BMW 6 amidships. Whodathunkit.

In any event, thanks again guys, and if anyone has more to add, please do so!


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 Post subject: Re: New member intro
PostPosted: December 16, 2015, 2:20 pm 
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What you may want to consider if you're still eyeballing the Locost/lotus route, and keeping in mind your 10k budget.. is an Exocet. Flyin Miata currently distributes them for MEV here, the sport kit is $7500. Add in a 1k Miata donor and for probably $9k out the door you have a seriously competitive chassis, with a manufacturer that sells and stocks replacement components and a super reliable Miata drivetrain.

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 Post subject: Re: New member intro
PostPosted: December 16, 2015, 2:44 pm 
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I'm always suspicious of any expense estimates coming from people who want your money. I'm curious what Locost builders have spent on their own cars; that could serve as a reality check against such cost claims.

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 Post subject: Re: New member intro
PostPosted: December 16, 2015, 3:02 pm 
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KB58 wrote:
I'm always suspicious of any expense estimates coming from people who want your money. I'm curious what Locost builders have spent on their own cars; that could serve as a reality check against such cost claims.


If I didn't know two extremely frugal people who had already built exocets purchased from FM, I would be suspicious as well. I've seen countless Cobra/Fiberfab etc kit cars start as an 8k kit and end up as a 35k finished product.

I think the difference between the Locost and something like the exocet, is the time that goes into building a locost. How do you measure time monetarily? IIRC The book estimates 3-400 hours of build time for a novice builder with a proper/complete donor. Say your time is worth $100/ hour, the average labor rate for a shop around here. You're now talking 30-40k in "labor" time. along with parts. I have mine budgeted to 2k, with a 1k contingency before It's drivable. I'm also massively frugal, and patient, and have a bunch of parts left over from previous cars, and managed to get a complete donor for $200.

So in my example, 33,000 - 43,000 including "labor" and parts.

The exocet is $7500 + estimate 1500 for a Miata donor and another 1k on the high end for miscellaneous stuff. roughly 100 hours of build time so 10k in "labor".. ~$20k?

Maybe I'm drastically off on my estimation, and it 100% depends on the quality and build style of your locost.

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 Post subject: Re: New member intro
PostPosted: December 16, 2015, 8:14 pm 
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I'm curious what Locost builders have spent on their own cars; that could serve as a reality check against such cost claims.
For me, about $5400, including tax and shipping on all materials I used. That doesn't include the costs for title/registration or upgrading after the initial build. I easily have well over 1000 hours and really didn't count. It is too easy to ignore the time spent on designing a "book' build with modern, USA sourced materials. There is no one I know that built a truly "book" build here in the USA. I probably could have removed ~$1,000 from my build If I wanted to skip reconditioning ALL of my parts.

There is a lot to be said for purchasing "kits" from dependable suppliers that will be around for 5-10 years or more. But few "kit" suppliers manage to succeed in the longevity dept. So up-paying for that possibility of having spare parts from mfgrs that may not be around next year? I'm not sure I'm in that camp.

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 Post subject: Re: New member intro
PostPosted: December 17, 2015, 2:10 pm 
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The Exocets are definitely a cool option, but if I go the Locost/Lotus route, it really does need to be a finished car. I've got no time at all to dedicate to another project. Now, that being said, I know that racing (/owning any vehicle) comes with the need for some periodic work and maintenance but that's something different altogether from a project like the Exocet would be. At least mentally it feels that way.


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