bmwe21.net forums

At the moment a 2.1 performance m42 head m44 block N/A, baby version of s50 s54.
aiming for 200bhp and as many revs as i can get.

but things always change.

I have considered the motorcycle engine route. BMW k1200rs turbo with a quaife reverse box. a friend is building an Atom like car with a busa holset hx35 turbo engine.

200hp is the bare minimum id say considering the lengths you have gone to and the weight of the car.

The problem with bike engines is the lack of torque (well until you boost them) but then again that sounds expensive and a bit specialist.

If your still deciding and wanna be different then maybe you might consider a bridge ported rotary engine.. they can easily spin to 9k.

I very nearly opted for one of them myself but bottled it because it wasnt an easy option compared to the m52.

more welding

nas80 wrote:200hp is the bare minimum id say considering the lengths you have gone to and the weight of the car.

The problem with bike engines is the lack of torque (well until you boost them) but then again that sounds expensive and a bit specialist.

If your still deciding and wanna be different then maybe you might consider a bridge ported rotary engine.. they can easily spin to 9k.

I very nearly opted for one of them myself but bottled it because it wasnt an easy option compared to the m52.

The Rx7 engine would be nice, but i would like to keep BMW, I do plan on trying to use a RX8 carbon prop if possible tho. They are a bit shorter tho.
Everything gets expensive when you want small light and powerfull, and that is the problem
Prime candidate is still M42/44 stroked bored and SC

i dont understand why people like to keep parts they fit "in the family" when theres plenty of workable solutions from other manufacturers (13B, sr20det, YB, C20let, f20c, ls3 etc etc). i sometimes wonder why i went for the m52 in my car but its tried and trusted and cheap (relatively)

The m44/22 supercharged frankenstien engine is a good plan i reckon, you might want to lower the compression so you can hit more boost, i got bored of 200hp fairly quickly. i think the magic number for an e21 is ~350hp ish

that rx8 prop will more than likely be a splined job rather then a bolt on effort we have on our cars already (going by the one i had on my FD3s), if anyone can do it its probably you who can work it out - when you do ill probably need one.

I'm not keen on non BMW engines in BMW. I love BMW 6 pots and they're just about the best straight sixes out there I reckon. There's no doubting the potential gains with a bastardised e21 though and a rotary with a couple of turbos would be good fun. I guess it's just personal preference.

I agree the M52 is a great engine, for me i like the OEM plus thing, on paper i think the S2000 with the 6spd is the best engine for me, just a shame it has a honda badge on it and costs a lot more than a £150 M42.

The prop is splined, so changes will have to be made, but they are cheap for what they are so worth a punt if it works out lighter.

I do think there are a lot of different bits you can use from different cars that are better. But why did BMW not install a high HP 4 pot in the E21 like they did for the E30 M3.

I want a E21 M3 cos I can't afford a E30 M3.

M42 was cracking in my old track car. (the one Jack now owns) I tried chipping it but M42's don't like it, despite what certain 'specialists' say. It did come with one of their chips and fuelling was awful. My lap times at Brands were quicker with the OE chip and it ran great. It sounded good too!

This is the M42.

Sounds nice.

and again, more welding:




1/8" inch plate


Dont know if i will fit these yet.


rear plates cut out

and some for fun

Lol epic camber.

but a lot of welding being done already!

Got bugger all done today, wifeys friend managed to rip the sideskirts of both sides of her car??? how do you manage that? made safe and told to go to a body shop!! I have more important things to do!!

Had a go at the cabriolet plates



just sat in place, My hole punch kit arrived so will punch some 1" hole in them, but still waiting on the swaging kit to swage the holes. To me they look a bit odd, possible to wide.

Comments please.

They do look odd but look like though they could reduce any flex, especially combined with a strut brace. Are you going to weld in a lower brace / wunderbar type thing? Have you considered a cage with a removable diagonal?

Shell is really coming along nicely.

I think i will cut them down a bit more to this shape


I will shape a piece of 1" x 2" box and weld right on the end of the chassis legs and spot welded to the very bottom lip of the front panel, right between the tow hooks.

I would like to weld in a strut brace picking up the bulkhead, but may have to do that after paint and engine install to ensure it doesent clash with anything

I plan to web the rear turrets to the arches and trialgulate the rear turret tops down to the top of the twin diff mount points.

I am still not keen on the cage as yet. Its not just the diagonals, the car could be used for weekend trips when finished and that means me, missus, 2.5yr daughter and baby ETA October.
so for me I want to keep the interior minimal but comfortable, with no dangers of heads hitting bars.

ISO fix x2 will be installed in the rear to enable car seats to be used.

NAS's idea of the triangle fender supports im still looking at,


I dont think they will work in the traditional way due to the way the front wing is bolted on for the E21 so may think of something else.