M42 BBTB group buy

[maggspower]

Hi there, first off, I hope I am OK running this off the strength of the last group buy. If not, mods, Gordon, please feel free to contact me.

Right M42 BBTBs. I have now managed to have a look at producing these and have done some research, and had a look at what is involved. They are more complicated to produce having two butterflys, and again I will have to make up some jigs and buy a few tools, but its safe to say we are on

The spec will be: standard small choke, this will retain drivability, and low throttle opening control. The larger of the chokes will be bored from 54mm to 57mm, and a new aluminium or brass butterfly installed.

Price for the conversion is £140, this is based on 7 people taking up the group buy, as I dont think they will be in demand quite so much. If we can get 10 I can take the price down to £130. If anyone is on any e36 forums then give them a heads up as these will fit m42 and m44engines fitted to their cars too.

You would be responsible for getting your throttle to me for the conversion and I will send it back special delivery (cost £10) so it is insured and signed for on the way back.

I have one in the pipeline for a customer already, so will need another 6 at least. I will need money upfront, and will need everyone to pay before getting started, this will allow for me to get the necessary tooling.

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[rix313]

I take it the 'when will this happen' question can only be answered when the list is full? This would be a nice little helper to the engine and ECU I have when it's up and running.

[maggspower]

I take it the 'when will this happen' question can only be answered when the list is full? This would be a nice little helper to the engine and ECU I have when it's up and running.

As soon as I have the 7 orders in, this will happen. I'll need time to make the jigs, and it maybe a good idea if people stagger sending them, that way the turn around will be quicker. I'm just one bloke in a shed

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[bilal-ali]

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[rix313]

Might be worth throwing a thread up in the m42 engine section?

[maggspower]

Might be worth throwing a thread up in the m42 engine section?

Good idea I'm on it.

[jon-m42]

Hi maggs

I have read up a fair bit on the bbtb for the 325's however never come across such insall on a e30 m42.

What are the advantages?

would anythign esle need to be changed or is thi just a straight swap with origional one?

cheers Jono Cool

[rix313]

It's a plug in and play mod Jon. Very straight forward. The advantages are the same as fitting a BBTB to any engine. By making the throttle larger you're allowing the air a freer entry into the manifold and also allowing more air in so the net result is the engine breathes and performs better. There are very few of these about for M42 so it will likely hold its value well which is another bonus.

[n1tr0_9]

Lame, just sold a standard spare tb for £15 on ebay. Wish id seen this earlier!

[ajay]

Here's one thats been done.




Only the main chamber is bored, i doubt any gain to be had from machining the smaller chamber, but they do work well with a chipped ecu or cams too i would imagine!

[rix313]

Do we have to supply the throttle body?

[maggspower]

Do we have to supply the throttle body?

Yes it will be a conversion, like i have been doing for the m20s. That way people get their own parts back, just seems fairer and people can't complain about wear, marks etc.

[jimbom30cab]

a well worthwhile conversion in my opinion, had mine (m20) fitted for a few months now and still enjoying the extra energy it seems to have.

no brainer really for the cost, a great deal.

[Huge]

count me in..

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[Huge]

count me in..

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[NoTurbo]

What is the difference between your one and this one? http://bimmertune.com/shop/engine-tunin ... y-1-detail

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[Connar]

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[Royalratch]

I'm in - in theory.

I spoke to Paul Sheppard (BMW engine tuner) and he said they tested similar set-ups and they made no more power. In some instances they lost torque.

The theory is sound obviously but he thinks without cam and head mods a BBTB can't be taken advantage of.

I'm up for one but is there any factual info on performance?

[NoTurbo]

I had one on a standard engine and had some gains at the very top end, improved sound and upper 1/3 throttle response.

At the low end I lost torque and engine pick up was slower.

If your engine flows better and has higher intake lift it should work well.

[Royalratch]

If your engine flows better and has higher intake lift it should work well.

What does that mean? I'm assume that 99% of M42 owners have no work done to their engine so why would it flow better? Also assume 99% of M42 owners do not have high lift cams either.

So all said and done - its takes the bad part of the M42 (poor low throttle response) and makes that worse?

And who is driving around at the 'top end' regularly?

[NoTurbo]

If your engine flows better and has higher intake lift it should work well.

What does that mean?

Means if you have had head work done or if you have built a stroker with larger capacity, or a higher compression engine that forces more air through. (all my assumptions btw)

[Royalratch]

Lol.

I knew what it meant I was being semi-sarcastic in that almost all 318iS owners do nothing to their engines. This BBTB would be a major upgrade!

[mcspike]

Sourced one (Y)

[rix313]

I should remove my name from this list as I have since sourced one of these.

And who is driving around at the 'top end' regularly?

In the minority here but my race car spends most of its life at the top of the range. I do have a higher lift cam than standard as well. Paul will be mapping my car when I get round to it