jmthunderbirdturbo New Reader
5/14/11 10:54 p.m.

Hello, all, haven't been on in awhile, but i have a new project in the works that im SURE you guys can help me with.

i have a 1990 E32 BMW 735il. Its a rough car, almost everything is broken, but it runs like a watch, and the transmission is flawless and strong. i thought about modding it and making it cool, but the associated parts are just too expensive.

Now, i also have a 1988 Ford Thunderbird Turbo Coupe. it was a 4cyl turbo 5 speed car, but the previous owner bought it for the drive line. he swapped it into his auto car, and gave me a low mile, straight bodied, 9/10 star rolling chassis.

im sure by now you can hear me think...

i did some preliminary measurements, and it looks like it will fit. its longer for sure, but with the right radiator, i think i can make it work well. the motor mounts are so simple that i can use almost any parts store rubber mount and adapt it to fit. i also read on a few different places that in Germany the 7 series of this era got a supercharger on some models, and the computer and fuel system on the U.S. models is identical, so adding a few psi of boost (5-7) shouldn't be a problem.

I went to a transmission shop and some ear bending there and found out that the trans is NOT electronic, so all i have to do is wire up the neutral and park lockout, the reverse light trigger, and find a way to make the VSS work.

heres my questions:

  1. id like to use the stock BMW cluster. i like the 160 speedo, the 8k tach, and the readout for the automatic transmission (S-sport, M-manaul, E-Auto) and the gear readout (P-N-R-D-3-2-1). can i use this? i can use the BMW's VSS to run the speedometer, and the tach should be an easy thing to hookup, but what about the digital readout? if the trans isnt electronic, how does the console sport/manual/auto switch do its thing? id like to use this switch too, can i?

  2. how much of the BMW wiring am i going to need? i want to use the factory motronics ECU and all it associated sensors, but ill be running Ford accessories, like A/C and brakes. the physical fab is no problem for me, but making it all work together so the ECU doesnt throw codes has me worried.

  3. am i correct is assuming the engine will hold a few pounds of boost without tearing it down? the car is a Turbo Coupe, so N/A is NOT and option...

  4. how much wiring in the dash will be needed to run the stock cluster? is this a dream, cause the wiring is so intertwined ill never sort it out, or is it a fairly simple harness i can pull and install in the Ford?

well stop there, but i have more questions. for now id just like some solid reading material if you all have any, and some insight from those who know the beamer stuff better than i do.

thanks in advance,


Travis_K SuperDork
5/15/11 5:12 a.m.

First, no offense, but this idea sounds like a huge amount of work to use to cars to make one cars that doesnt work as well as either of the ones used to make it. But, that said, there was a Lincoln that came with a BMW diesel, which if you could find parts from one may at least make mounting the drivetrain easier.

stuart in mn
stuart in mn SuperDork
5/15/11 10:13 a.m.

The BMW turbo diesel in the Lincoln was based on their M20 'baby' six 2.5L engine, so the mounts are different from the M30 3.5L engine out of your 735iL.

BMW did build a turbocharged 7 series, the turbocharged 745i in the early 1980s. It used the same basic engine as you have in your car. They weren't officially sold in the US so you only find grey market imports in the states; there aren't very many of them plus the parts are 30 year old technology. The M30 engine does respond well to boost, and there are better options today. You can buy a kit all ready to go from, and there are people who are home brewing their own solutions, check out Scotty Sharpe's forum:

BigD New Reader
5/15/11 10:43 a.m.

The M30 will make a proven 500whp/600wftlbs on a stock engine, so you've got the right idea there. Unfortunately your transmission will blow up. They're notoriously weak even with stock motors.

I'd scrap the idea of using the cluster, as you will most likely have to add all of your own sensors and wiring. Strap an aftermarket speedo overtop of the stock one and be done with it. While you're at it, the tach too. Gauges are just voltmeters and the signal for the tach is done by converting a frequency to a voltage. You've currently got a cluster designed for a 4 cylinder ignition pulse, and you're changing to a 6 cyl engine. At best, you will need a converter box (make one or buy an aftermarket - they're spendy though). Or make a mental note of key rpm values as it will read about 50% too high.

The wiring won't be a big deal as these engines didn't come with antitheft, or were wired up the butt into the car for traction control and the like. The interface with the chassis wiring will be quite primitive (things like main power, fuel pump signal, start, wheel speed, fuel economy, transmission state [for an auto]). So basically you can just wire the power and fuel pump connections, and it'll probably run just fine.

Luke SuperDork
5/15/11 10:57 a.m.
BigD wrote: The M30 will make a proven 500whp/600wftlbs on a stock engine, so you've got the right idea there. Unfortunately your transmission will blow up. They're notoriously weak even with stock motors.

How does the manual trans fare? (I've been idly thinking of turbo-charging my own M30.)

BigD New Reader
5/15/11 11:04 a.m.
Luke wrote: How does the manual trans fare? (I've been idly thinking of turbo-charging my own M30.)

Never heard of one letting go, other than the normal things like bad syncros after half a mil KMs. The guy with the 550whp car has been beating on it for years. Best of all, finding one is easy, since the M30 was in so many cars, and none of them are desirable (ie cheap). Plus the M5 280 Getrag is a bolt on if you can find one.

corytate Reader
5/15/11 6:49 p.m.

i like the driveline idea, just megasquirt it and run a haltech or something similar.
Idk, thats what I think I'd do lol
And I agree that you cannot put an n/a motor into a super coupe
saw some guy at the shop the other day who put a 2.3 turbo into his REAL, LEGITIMATE foxbody saleen, numbered and all.
it bummed me out.

jmthunderbirdturbo New Reader
5/16/11 6:27 p.m.

Travis-im a huge fab guy, so mounting and such is nothing. Stewart- i will brew my own setup. Ive been building turbo cars for awhile, 2 t birds, so i know my way around a turbo. I intend to keep stock computer and such, maybe add like 10 percent larger fuel injectors, run an afpr and a wideband, tune with pressure and vam spring. Ive run deep 11s with less... Big d- the cluster i want to use is the bmw cluster. Good info on the wiring, thanks. Corytate- not super coupe... Turbocoupe lol. And the bmw computer will be fine. This a fun project for my wife to drive so it doesnt need 500hp...

What will the trans handle? Will 5psi kill it? 8? Can i rebuild it cheap when it goes?


Our Preferred Partners