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Hi fellow e28 board members, Ive been considering of doing a very mild boost or I guess you can say stock boost on my 89 635csi. The donor car that Im looking at is a 85 745i turbo. I was wanting to basically keep everything at stock settings unless its possible to tweak the k27 to put out 7 or 8lbs of boost rather than 6lbs without too much work. So Id be hoping to get about 265hp. Reason for modest boost is the 6 only has 64K original miles and I want to keep it reliable as possible cause it is my DD and I would want to keep all the internals stock. So what I was wondering what kind of work would be required to swap all the goodies off the donor car into the 6? Would it require any extra modifications/upgrades and parts to do it or would it be as easy as removing everything pertaing to the turbo and installing it into my car. I know they are probably really silly questions so please dont flame me for it. Any input would be appreciated. Thanks

Try searching this forum for answers. A few of us are running some of the 745 gear and have build threads. It all won't bolt on to a E24 and you will need to get fuel management as the 745 dme won't work on your car.

Im trying to search but it all seems scattered to me. I guess more specifically is there anyone who used the turbo components from the 745i to turbocharge their m30b35? I know that people use the whole motor (the m102 or m106) but I didnt want to go that route. I Know that theres alot of info but it seems scattered to me. Is there anybody close to Spokane WA who can help me out with this? Thanks

Ill help you out with what you need to know in a pm.

89 635csi + 85 745i = 89 645csi

righteousrags88 wrote:Im trying to search but it all seems scattered to me. I guess more specifically is there anyone who used the turbo components from the 745i to turbocharge their m30b35? I know that people use the whole motor (the m102 or m106) but I didnt want to go that route. I Know that theres alot of info but it seems scattered to me. Is there anybody close to Spokane WA who can help me out with this? Thanks

People do it all the time. Cvillebimmer's E32 735i had this turbo setup before it found its way onto another car.

Don't you have to cut something from the right inner fender to use the stock 745 stuff in an E24?

I will be looking into this. Thank you

wkohler wrote:Don't you have to cut something from the right inner fender to use the stock 745 stuff in an E24?

My guess is that to make the 745i intercooler fit, you get to start hacking. I wouldn't use that intercooler anyway though.

I thought it was back by where the waste gate comes off the manifold. I couldn't remember where I saw it but I had seen it.

wkohler wrote:I thought it was back by where the waste gate comes off the manifold. I couldn't remember where I saw it but I had seen it.

Looks like you are right about the WG.

From user Diego_C on Big Coupe.

Thanks for the picture. Makes a great reference. Would it cause any problems structurally to the vehicle by cutting into the frame like that?

I think it would be completely stupid on a nice low mileage car. There are better turbo options that won't compromise the car.

Indeed the reinforcement of inner fender needs to be adapted slightly to have enough room for the wastegate to fit.

From memory what is needed to bolt the m102 or m106 setup to an m30 in an e24 is the following:

M8 to M10 studs to mount the manifold.
Stock engine mount can be used (m30b28), but needs to be trimmed a bit.

3 to 4 big washers should be used to tilt the engine about a cm or 2 to make enough room for the wastegate to clear.

Oilpan must be drilled for the oil return

Stock 745 downpipe can be used as a basis, but needs to be cut up an rewelded, because the stock 745 one will never fit.

Additionally I added 24 lb bosch injectors, begi rrfpr 2025 and a manual boost controller. I also changed the spring tension of the air flow meter a couple of clicks.

I'm running currently 6 psi non intercooled in the 628.

You can find some more info on bigcoupe.com in the project section, search for project 628.

wkohler wrote:I think it would be completely stupid on a nice low mileage car. There are better turbo options that won't compromise the car.

Agreed. To the OP, there are also turbo options that don't use 25+ year old antiquated turbo technology, but those options will be more expensive. However, if you have the parts, you can make them work.

Good info Diego_C.

Thank You for all the responses. I guess now it all depends on how much the donor 745i gets auctioned off for.