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Updating an M635csi Track Car to a Race Car

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VintageRacer
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Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Tue Oct 17, 2017 1:08 am

Well folks I thought I would share some pictures and progress on restoring/building up an M635csi that I purchased out of south Florida in Aug. Here is how I found it.
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After talking to the owner for about 30 minutes he took me for a short ride (it was raining so we couldn't really go test it out to the limits) and I was sold and into my trailer it went for the long drive back to Waco, TX.

The car was imported in the late 1990's from Germany and converted into a track car for HPDE events and as such, never received a log book. The engine is a 4.0L S38 build by Power Plant Racing in South Carolina running custom forged pistons/rods and a one piece billet crankshaft. Compression ratio is 12.5:1 and the cams are Shrick 280ish race cams. The engine has about 7.5 hours since rebuild and a recent dyno sheet puts it at right around 425shp on 110 leaded race fuel. The old Motec is long gone and the engine's fuel and spark is now managed by an old but solid Electromotive TEC2.
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The suspension is custom cut down strut housings in front with race valved Bilstein inserts and camber plates. The rears are a small body coil-over shock. The rear subframe has been modified for toe/camber adjustment as well.

Brakes are huge. The front uses Euro M5 four piston calipers with 345mm two piece floating rotors. The rears are wilwood dynalite 2 four piston calipers.

Tires are 245's on all four corners with TSW 17x8 wheels.

After getting it home my father I proceeded to gut the remaining BMW factory harness, gauges, heater core, AC evap, etc etc etc. Enough for 4 rubbermaid bins of parts.

My goal is to have this car compete in SCCA SPO class as well as mainly compete in SVRA and VSCDA vintage racing events with my father and his TWR XJS. Thus the car needed to be updated to the current GCR for logbook issue. So into the shop it went.

After several long tedious weekends I have finally finished the new electrical system. The goal wasn't to replicate the AC Schnitzer car but to create an interior/electrical panel that was inspired by it.
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The new Momo seat should help keep my head straight, the dash uses VDO gauges like the original and the warning lights are in similar spots as well. I have also finished a new side exit open exhaust complete with a new MTX-L wideband to monitor the fuel curve.

Next stop will be for the car to head to Austin TX where Winding Road Racing will be installing a new cage and window net.

After return from the roll-cage I'll be installing a new ATL 22 Gallon fuel cell, Aeromotive A1000 fuel pump, Aeromotive EFI regulator and all new plumbing up to a Nuke fuel rail.

To complete the safety gear a new OMP fire suppression system will be installed along with new in date seat belts.

The goal will be to get a logbook in January and racing at the SCCA super school at MSR Cresson 27-28 JAN 2018.

Wish me luck!

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TBM
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Re: Updating an M635csi Track Car to a Race Car

Post by TBM » Tue Oct 17, 2017 4:17 am

So I'll be the first to wish you luck!! Awesome car..

You might find that if you relocate the overflow tank and install a custom large intake plenum with the longer runners you will see torque restored..and maybe even suck in cooler air. Remember even the racing E9's with the M49 ran a plenum. Might be worth a try especially if you tune it correctly.

OH and why not run one less belt and install a superlight but effective Davies Craig electric water pump. You'll reduce parasitic losses
(if that's allowed in the series you are running)
'84 M635csi
'86 Lotus esprit Turbo (sold)

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tschultz
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Re: Updating an M635csi Track Car to a Race Car

Post by tschultz » Tue Oct 17, 2017 12:50 pm

REally cool-- we need more photos though!

I have to say it may not be competitive with the newer metal, but you will have a blast and it will be a conversation starter!

The biggest weakness seems to be the power/weight ratio and the older suspension design. Dropping the weight will be your key to being competitive.

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Tue Oct 17, 2017 5:18 pm

The goal isn't to be "competitive." I had a chance a long time ago to become a professional driver and I joined the USAF instead to fly airplanes. Now I'm just trying to have some fun. The car is fairly light already right around 2800lbs. I am going to try and shave a bit more off that.

As far as creating a plenum I've thought about doing that. The simple fact that those air filters are a royal pain to remove and do any work motivates me to do that. However, its low on the priority list. This motor has more HP and torque than I could ever need, it pulls like a freight train.

I'll try to update some pictures once I get the cage done and interior work finished.

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Re: Updating an M635csi Track Car to a Race Car

Post by GazM3 » Wed Oct 18, 2017 4:18 am

What a great project

It must take some bravery to build a race car out of a genuine m635csi but I guess it's already part the way down that track anyway.

Most of the big power m88/3 engines seem to run without a plenum. Perhaps it's just the fact they love listening to the open intake at high rpm. Even the procar had open trumpet intake Drawing hot intake air is less of an issue as it's on the cold side of the engine. Perhaps a simple fabricated heat shield will be sufficient.

Good HP for sure no doubt helped by the high comp and improved fuel. Perhaps running on e85 would be a consideration. Much cheaper than race gas.

Looking forward to monitoring your progress
BMW’s
74 2002 2.3ltr
84 E24 M635csi
94 E34 540i/6 SC
97 E36 M3 euro SC U/C

OTHERS
02 Landrover D2 td5
08 Holden Ute 6.0
11 Audi S5

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Re: Updating an M635csi Track Car to a Race Car

Post by matthewdesigns » Wed Oct 18, 2017 5:27 am

Thanks for sharing this...great project you have there. Would love to see some on-track video footage once you get it sorted and head out for some laps!
'84 633CSi
Arctic White/Pearl Beige

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Wed Oct 18, 2017 5:44 pm

I would NEVER have cut up an original M! Unfortunately the car was already well modified by the time I got it. I was disappointed to see the trunk spare tire well was cut to accommodate a fuel cell. The good news is that nothing was else was cut or modified that can't be put back.

I'll be be posting more videos and pictures as we get the car done. I'll be campaigning the car at several SVRA events next season including Road America, Indianapolis and Austin (provided I get invited).

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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Tue Nov 28, 2017 7:34 pm

Quick update on the car progress. It is back from Winding Road Racing in Austin TX. They installed a new 8 point cage with cross bracing, new mounts for an FIA 6 point harness and they trimmed the dash to fit the new cage. I've also got the interior and trunk painted red like the original car, and the side holes for the trim are all welded up. The car goes to the body shop Thursday for a fresh respray in Alpine white.

The new fuel cell from ATL should be here next week as well.

For those interested I have also purchased nearly every nut, bolt, screw and rubber trim to redo my front euro bumper which was in otherwise good shape. I can HIGHLY recommend www.wallothnesch.com Not only did the parts get here in only a few days they sent me a complete 3 ring binder illustrated parts guide to my car. I'm impressed.

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Thu Nov 30, 2017 2:30 pm

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Re: Updating an M635csi Track Car to a Race Car

Post by tschultz » Thu Nov 30, 2017 3:03 pm

This thing is sweet, great job!

I elected for M30 turbo for track use since it is a bit cheaper to get parts, but I haven't yet made it down the rabbit hole of cage and removing weight.

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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Wed Jan 31, 2018 9:22 pm

Well the car is finished and I was able to complete my first SCCA event this past weekend gaining a novice permit and well on my way to a full SVRA licence.

Next up on the task list are to adjust the valves, sync the throttle bodies, check the clutch and add a scatter shield and redo the brakes (leaky rear bleeder).
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Re: Updating an M635csi Track Car to a Race Car

Post by baders » Wed Jan 31, 2018 11:37 pm

Very nice ! I'd be interested in a handling report. How would you compare it on the track to other cars you may have driven ?
1986 635csi LOCUTUS
Arktis Blau Metallic / Pearl Beige
S38B36/Close ratio dogleg 5sp
Perth Australia.

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tschultz
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Re: Updating an M635csi Track Car to a Race Car

Post by tschultz » Thu Feb 01, 2018 2:20 pm

Looks awesome... but why did you select BBS RS740's (Style 42's)? They are very heavy at something like 22 pounds each. I'd suggest BBS RK 003's as they are 17x8.5" et 15 (wider track should be a good thing) and only 17 or 18 pounds. I actually have a lead of two sets local to me for a fair price...

Let me know if you'd be interested via PM and I can start the conversations...
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BBS RK 003 wheels
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GazM3
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Re: Updating an M635csi Track Car to a Race Car

Post by GazM3 » Sat Feb 03, 2018 11:11 pm

Looks really good. Love the paint and the decals.


Are u still selling the front brakes ?

I’m still interested in them if so.
BMW’s
74 2002 2.3ltr
84 E24 M635csi
94 E34 540i/6 SC
97 E36 M3 euro SC U/C

OTHERS
02 Landrover D2 td5
08 Holden Ute 6.0
11 Audi S5

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Sat Feb 03, 2018 11:31 pm

The E39 wheels came in an 8/9 stagger and I was able to acquire two sets locally. It's a vintage race car so 5lbs of weight (even unsprung) isn't going to matter. 8.5 is too narrow for the 275 R7s out back.

As far as handling it's a very neutral car. It has very nice turn in with good power on oversteer that's very controllable. As I got to know the car my lap times got better all day. Having a 450hp S38 helps too. To be honest I wasn't pushing it too hard because of the amount of money invested and I am likely going to be offering it up for sale this fall so I can concentrate on my GT2 car or acquire something else.

As part of the brake upgrade I'll be moving to wilwood integra calipers and Coleman rotors. Gaz my only concern is shipping to Australia and the cost.

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Re: Updating an M635csi Track Car to a Race Car

Post by GazM3 » Mon Feb 05, 2018 1:58 am

Shipping won’t be cheap but I can’t do much about where I live.
BMW’s
74 2002 2.3ltr
84 E24 M635csi
94 E34 540i/6 SC
97 E36 M3 euro SC U/C

OTHERS
02 Landrover D2 td5
08 Holden Ute 6.0
11 Audi S5

Shipper 01
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Re: Updating an M635csi Track Car to a Race Car

Post by Shipper 01 » Thu Feb 15, 2018 1:13 am

This is a lovely looking racer.

Have you thought of one of these air boxes? https://www.ebay.de/itm/BMW-M5-E34-Carb ... SwK7FWh~nh

Let us know when it goes on sale. Gaz may need to fight me, or his wife, or both of us.

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MrE
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Re: Updating an M635csi Track Car to a Race Car

Post by MrE » Sat Feb 17, 2018 6:54 am

Wow!! This is impressive work. That car looks marvellous. Can't wait to see more. Keep us informed!!
Image

Shipper 01
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Re: Updating an M635csi Track Car to a Race Car

Post by Shipper 01 » Sun Feb 18, 2018 11:53 pm

What's the spec/exact colour code of that red you painted the floor with? I'd be interested in something like that for my E3 racer.

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ericono
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Re: Updating an M635csi Track Car to a Race Car

Post by ericono » Fri Mar 16, 2018 12:41 pm

Hello. What are your thoughts on the work done by Power Plant Racing on the engine? How many miles on the car since their work? How many of those on a track?

Thanks,

Eric
'85 M635, '00 528iT, '98 Z3

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Mon Mar 19, 2018 4:34 pm

I can't say enough good things about Powerplant. Henry answers the phone and email and has given me good support after the sale. The red paint is a generic GM paint code for "Red."

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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Thu Jun 21, 2018 3:05 pm

If anyone is interested in seeing the car on track I've posted several pictures and videos to my instagram account. @RapidTerrier

Unfortunately I don't think I can post the videos here.

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Re: Updating an M635csi Track Car to a Race Car

Post by tschultz » Sat Jun 23, 2018 2:02 pm

Can you upload to Youtube and share a link maybe?

VintageRacer
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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Fri Jun 29, 2018 1:25 pm

https://youtu.be/rwU2XdmhWRE

This is my favorite video. The engine is just amazing sounding

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Re: Updating an M635csi Track Car to a Race Car

Post by VintageRacer » Thu Aug 23, 2018 10:26 pm

Well a quick update on the car. It performed wonderful at Road America for the second time this year. The next race will be the SVRA national championships at Circuit of the Americas November 1-4. I'm in the process of swapping over to AP Racing front brakes and centerlock wheels.
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After the November race I'll be developing a kit to replace the Getrag 265/6 with a much better Tremec TKO transmission. This will consist of an adapter plate to mount the TKO to the Getrag bellhousing, new pilot bearing, 240mm 26 spline clutch disc, cross member and driveshaft. After it's all said and done the shifter location appears to be in the correct location and with the additional length of the tail housing I may swap to a 1 piece driveshaft if I can get the angles correct. The ratios of the Tremec very closely match the Getrag 280 but with a 0.83 overdrive. I'll be sending it up to Liberty Gear in Michigan for installation of Dog Rings and new bearings.

Because I really don't want to trash the 4.0L S38 and considering it's rarity I'll also be building up a 300+hp 8000 rpm M30 so watch for that build coming soon. For you nay sayers it can be and has been done with all the old group A cars back in the 1980's. I'm not saying it will be streetable but it's a race car. Here is my initial plan:

M30B35 starting point
VAC Stage 3 Head with dual springs titanium retainers etc
VAC 314 Race Cam with Billet Rockers, Shaft Locks and Oversize valves
Extrude Honed Intake and Big Bore TB
Larger 32lb/hr injectors and billet Nuke fuel rail
Megasquirt PnP running Speed Density (no AFM)
Custom 93mm 12:1 Forged Pistons
Shot peen rods with ARP bolts
Full balence
Lightweight flywheel

From my research this is about as close as I can figure that the original group A cars ran. I'm hoping VAC's new tech and head development will allow a bit more than original.

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