M40 on bike throttle bodys

[LeonNewton]

I am building a lotus 7 styled car with BMW running gear. I am opting for a m40b18 first of and will upgrade to a m42 a year or so after the build hits the road.
I am curentley mock fitting the engion to fab up all the engeion box and diff mounts and am aware of the hight of theys BMW engions. Not a problem I canot get over but without the intake running across the top of the rocker cover the whole lot wuld be a bit squoter.
In the past this has been resolved bye fitting bike carbes or throttle bodys on other engions.
I hawever hawnot realy got a clue haw I would do this to a old BMW engion. I am running ifi so tb's are the way to go. Fabricating a manifoled I can do, but geting if to work???????
Can anyone help or surgest some worth wile Reading?

[Luca318is]

found here:
http://retrorides.proboards.com/index.c ... 996&page=1






you have to leave the M40 electronic for the ignition

[toby]

But to quote the builder of that
"BMW M40 1.6 - GSXR carbs never finished this.. started it then got distracted by big engines..

cheers"

'Hard to get working right' is the phrase I've heard in relation to these things.

[Chris]

Start with the M42 engine.

It will be a whole lot easier in the long run.

Bike carbs are do-able but a pain in the arse from start to finish, ITB's are a lot easier. But then you have to choose between trying to get the BMW electronics to work, (troublesome and untidy) or fitting standalone manegement, (complicated)

Either way, have fun. And check out http://www.locostbuilders.co.uk it's all been done before.

Cheers
Chris

[LeonNewton]

Thanks chaps. So it is obveousley do able. And I hope it can be dun with standerd ecu. Gess I shuld just get a set of 38mm plus throttle bodeys. Put them on. And find out why it does not work.

[stonesie]

For the manifold check out Bogg Brothers ( http://www.boggbros.co.uk/ )

Good luck with the project

[LeonNewton]

Thanks man. I am a welder and fabricatore so the manifold is the only bit I know I can do. Will be calling them back Wednesday afternoon for a quick overe the phone chat about wot to do. Seem like good chaps. Tar.

[daimlerman]

Been thinking about this,Leon.
How's your chassis doing?
If engine hieght is the main issue,how about modifying the sump to help? I am thinking of removing the pan at the front of the engine,that should reduce it's hieght by 2/3 inches...you could use a remote tank like British bike makers used to,add an oil cooler to help replace capacity...a simple steel pan that just clears the crank would do the job?
May well be a whole lot easier than trying to get the thing to run right on bike t/b's!

[LeonNewton]

Chears man. The chassis is coming along good tar. Just some bits to do befor crimbo when I won't to paint it. Din thinking of takeing it of the sump, though it is ally and has heat displasing wings ( dam canot remember proper word) all over it. It would no dawt be an easear option. Must say I quite fancey 4 little filters sticking out the side mind. Lol. But you are right. Choped sump and a cupple of mx5 style oil cooling hoops behind the nose will help.

[LeonNewton]

I remember why I canot drop the engion. Well wot problems it induces.
Dawn the drivers side of the engion bay sits an extra rail to beef up the tubes relating to steering. Under this is steering and peddel box bits ( brake and clutch cilinders) above is the exhaust maniforld. It does not all fit below this bar. So if I drop the block. I need to be clever with somthing elce.

I am glad I started this.

[Gortour]

Didn't Rob (Lance1a) do this with an M10?

[Jon_Bmw]

I suspect Rob used twin Carbs.

[Gortour]

I vaguely remember he had 4 motorbike carbs from something...?

[LeonNewton]

Yer carb replacment for bike carbs is dun and quite simple. It's all the elcetronics I don't understand. I culd youse bike carbs and plank the fule rail. This has been dune to many 2.0 ford engions. Though not somthing I fancy doing.

[SteMarsden]

Good to hear its going well Leon, any chance of some pics of this?

[LeonNewton]

I started a build thred but it got daleated.

[Chris]

The injectors and everything should be fine. The TPS should be fairly easy to sort out, the one big problem i can see is what to do about the AFM on OEM engine managment????

Hence why i suggested standalone.

If your worried about the electrics, go with carbs.

Need more regular tinkering with, but in a seven your not gonna be hunting for high MPG figures so shouldn't be to much of a problem.

With the sump thing, you could always take the deep pan down an inch or two and extend the rest of it to match. Then keeping good oil capacity and lowering a bit (which if nothing else is good for the handling)

Chris

[LeonNewton]

Think you have pritey mutch outlined the problem purfectley. That is also about as deep into it as I can think.
Is there a way to install somthing the ecu thinks is an afm or indeead a way of meatering things another way for the ecu.

[engine_ear]

Can you make up a simple manifold that the original throttle body will fit to?
I'm thinking an ally tube with the throttle body bolted to one end and 4 branches off it to the head. The ICV should be easy enough to plumb in, then all the original electronics should work.
If the M40 is only a stop gap then just seems the easiest way to me of getting it working

Are you using the BMW rear end at all in this? Sounds an interesting project.

[LeonNewton]

I am yousing the diff and drive shafts going to fabricated uprights holding BMW rear whealbarings and drive flandges with BMW rear drums all suported on fabricated dubble wishbones.
if that makes sence.
I am also naw thinking that I culd just youse my is engion and sort this problem out once.

The idear of a custom manifold is one I had today in work. I was thinkng of mabey doing it with a long chamber to the righ of the engion with the stb and afm going to an air box in the side of he car and 4 branches going to the block. Haw will the sizes of both the box and the individual tubes to the block afect performance?