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DISCUSSION => Swaps, Turbos, Buildups => Topic started by: Duffie on August 17, 2017, 08:10:51 AM

Title: M42 semi race engine - Possible turbo build
Post by: Duffie on August 17, 2017, 08:10:51 AM

Hello everyone!

I have a BMW E21 race car, which has a 290 hp S14 in it.
Now this engine is going out for a full rebuild. As you guys probably know s14 part prices are insane these days, so i expect the wont be ready for quite a bit.

So i decided to build a budget m42 to use in the meantime.

I have
a complete m42b18 e36 engine
M47d20 88mm crankshaft
S50B32 throttle bodies
DTA s60 ecu

From what ive been reading these parts are useable to make a fun engine.

I guess my questions are these:

What rods/pistons do i use?
Headwork?
What will i need to do to get about 200 flywheel hp?

Thanks for the help!

Tommy

Title: Re: M42 semi race N/A engine
Post by: jerseytim on August 17, 2017, 06:42:07 PM

you can use the m42 rods and get pistons made to fit, you could use 86mm pistons and get the rods made to fit or you could use m42 rods with vauxhall pistons but you will have to deck the block as the pistons will be too low and you will need bushes in the rods as the gudgeon pin is narrower. if you deck the block you then get timing chain issues and sealing problems with the timing chain cover, the cams might need replacing to make 200bhp and the cams i use needed solid lifters which cost a fortune. i could do you a favour and swap your s14 for my m42 ;)

Title: Re: M42 semi race N/A engine
Post by: Duffie on August 26, 2017, 02:07:07 PM

hi again, and thanks for the reply :)

Ive been thinking of going with M42 stroker turbo instead, and was wondering if anyone could help me with the compression ratio of a setup ive been thinking of.

Standard M42 block
M47d20 crankshaft 88mm
Stock M42B18 pistons
135 mm M50b25 conrods NV

Any help appreciated greatly!