Real Fiero Tech

You may have seen my other thread, where I mused about putting a V8 in a BMW of some sort:

I've settled on an E46 M3 chassis.

I intend to purchase a 2002-2004 M3 before the end of the year. I'll drive with the stock drivetrain for a while as I reverse engineer the BMW engine computer's CAN bus messages so I can engineer a clever solution for making the chassis computers happy with the S54 gone.

This thread will detail suspension and chassis modifications which I develop as I drive the car with its stock drivetrain. I'd like to have the chassis mostly sorted out before beginning the V8 swap.


UPDATE: Vehicle acquired!

Do you have anything in particular in mind?

I would have thought the E46 suspension would be a well known quantity...

Although I do admit that a very large fraction of the suspension work I rear about is of the [Vader]You don't know the power of the STANCE[/Vader] variety.

I plan to track the car and do some autocross with it stock (or however it is when I buy it), and slowly add modifications as needed. Ultimately, I'll probably end up with the following:

• Wheels - D-Force 18x10 (front and rear)
• Tires - 285/30/18 Yokohama Advan Neova AD08 (front and rear)
• Vorshlag wheel studs and spacers (need thin spacers on the front to get the tires to fit)
• AST 4250 double-adjustable coilovers
• 500#/in front, 550 #/in rear springs
• Vorshlag camber plates
• Powerflex suspension bushings
• Hotchkis swaybars
• Bimmerworld solid brake guide bushings

Not sure about brakes yet.

Ultimately (after the V8 swap), I will probably compete with the car in NASA TTS.

Series8217 wrote:I plan to track the car and do some autocross with it stock (or however it is when I buy it), and slowly add modifications as needed. Ultimately, I'll probably end up with the following:

• Powerflex suspension bushings

Not spherical bearings in the lateral links?

The Dark Side of Will wrote:

Series8217 wrote:I plan to track the car and do some autocross with it stock (or however it is when I buy it), and slowly add modifications as needed. Ultimately, I'll probably end up with the following:

• Powerflex suspension bushings

Not spherical bearings in the lateral links?

Unnecessary. It's no Fiero!

I figured you'd go all the way, making the most of the effort BMW put into isolating the lateral and longitudinal compliances of the suspension (e.g. the L-shaped control arms in the front).

The plan for now is a street/track build. If it becomes full race it'll get a cage and more serious suspension (AST 5300s, rod ends & spherical bearings).

Just like the '88 Fiero, you can put spherical bearings in the lateral link pivots and keep the rubber bushing in the trailing arm.

RealOEM calls the outer pivots of the lateral links which are captured in the trailing arm "ball joints" (callouts 2 & 3), while the inner pivots are "rubber mountings" (callouts 6 & 14)... So it would probably be comparatively easy to swap those out for spherical bearings, while leaving the rubber bushings in the forward trailing arm pivots (callout 4)...

http://www.realoem.com/bmw/showparts.do ... g=33&fg=30

Now that I have the cash there are no silver gray 6-speed M3s on the market in my area... grrr...

Still looking.

At this point I'm considering buying an SMG car. The benefit is improved track performance before I do the swap, at the expense of greater complexity and more expensive repairs if the SMG-specific parts fail. It's relatively easy and inexpensive (< $1000) to convert the SMG to a manual, so I can always take that route if I absolutely hate the SMG or if it breaks. Converting the chassis for a manual trans is also relatively easy, since the 330i pedal assembly and whatnot just drop right in, so it won't affect Stage 2 too much. The only trouble for Stage 2 is that I will be debugging body modules reflashed for a manual trans at the same time I'm debugging the engine swap.

I know Will is going to tell me again to make the SMG stuff work on the T56, and I agree that the driving experience would be totally awesome, but integrating a failure-prone $2000 BMW part (the SMG hydraulic pump) into the car seems like a bad idea.

An Oxford Green/Cinnamon (my dream color combo, and super ultra rare) M3 popped up on Craigslist locally but it was a 'vert .

This one is also a convertible, but it shows just how gorgeous this color combo is: http://farm6.static.flickr.com/5042/564 ... 2727_b.jpg

Redying the leather interior is not an impossible or particularly hard job, just time consuming. So if I find an Oxford Green car with good paint and a black interior I'll probably jump on that too.

If only paint jobs weren't so expensive

Not quite related to paint/interior questions...
There's been at least one S54 swap into an E46 330xi, so the front drive hardware definitely works with that engine. An AWD M3 would be pretty sweeet.

The black car with the high ride height? I did see that. It does prove that the front drive hardware works with the S54, though it doesn't prove that the front drive hardware fits in an M3 chassis. Also, I haven't been able to find details about that swap, but I suspect they used an M54 AWD oil pan, which would eliminate "semi dry-sump"* pan of the S54, which has a second pickup that scavenges from a shallow front sump to the deep rear sump. I don't know how bad windage losses would be without the S54 pan, but an 8000 RPM motor can probably use all the help it can get.

I'd be more interested in making it AWD with the LSx motor

I haven't audited the sheet metal parts list to see if the AWD and M3 bodies use different structure up front, but the AWD definitely uses a different subframe than the RWD/M3. BMW *MAY* have been able to make the AWD and RWD front structure similar enough in the E46 that the AWD hardware just bolts in.

One thing I'd like to do with Bad Idea is to snag an E30 M3 rolling shell, cut off the M3 front structure and install the E30 AWD front structure... I'd end up with an AWD V8 M3.

I totally hear you regarding the LSx AWD M3... that would be a sweeeet ride. I might even go iron block/turbo on a ride like that.

I drove around in a ~2900-lb 316 whp E46 M3 SMG car for awhile today. It's basically stripped out with a bunch of carbon fiber body panels, low-compliance bushings, and a 4.10 clutch LSD. It was on 255 street tires today, so needless to say it had no grip whatsoever relative to its power-to-weight ratio.

The SMG is definitely not for me. It felt very disconnected and unpredictable, even though I was controlling the gears. It doesn't stack downshifts so it's hard to know what gear you're in after slowing down unless you look down at the instrument panel. The gear indicator is not very big, nor is it very distinct, so this is not a quick process.

I'll be tracking the car at Buttonwillow this weekend (with much wider, stickier tires), so I'll have more impressions after that, but so far I don't like the SMG. Cool car though.

Well that was fun! The SMG shines on the track. Still can't stand it on the street though.

A stiffly-sprung sub-10-lbs per wheel-HP E46 M3 on heat-cycled 255 slicks is not easy to control at the limit. In ~80 minutes of track time I went off only once, but I only drove the car at 7/10 besides the slower turns (and the fast one I went off on).

Stage 1 of my build is definitely going to have to be about developing a stable, predictable chassis and working on my own car control and driving skills.

Still planning on TT? Now with the restructure, TT1?

Unsafe At Any Speed wrote:Still planning on TT? Now with the restructure, TT1?

Stage 1 of the build may still end up in TTB.

With the V8 swap likely TT3 or TT2, depending on how much weight reduction I do.

Looking at a couple cars this weekend.

If you buy an M3 you'll never drive your Fiero again. Not saying that's a bad thing, but there's an extra $3-4k you can put toward an E46.

I've driven E46 and E36 M3s at the track. I still like the Fiero as a track car. It's a completely different driving experience.

Test drove two today. Not sure which one to get.. both have no recent service records (but apparently service was performed by individuals). One is immaculate and the other is relatively cheap.

Not a lot of time left. I really need to have a car by Monday or Tuesday at the absolute latest so I can have it ready to drive on Friday.