e36 m3 Individual Throttle Bodies to m42 conversion.

[Alburglar]

Well here is the story so far. I bought these off a guy on here who had already removed the middle pair (as e36 m3 is a 6pot for those who don't know). The throttle bar had already been cut down and the vacuum bar and injector bar had also had the middle cut out.
This is them offered up

The two bottom holes line up nicely, But none of the top holes do

I drew round a gasket onto wood to make a template i could bolt through

cut off the top tabs
same again on the spare body
and got it ready to weld.

[Alburglar]

Now comes the hard bit...TIG welding cast ally! ...which I left to my tutor! I am currently at the start of C&G Tig welding and this is beyond me at the moment.

The two pairs got welded together slightly twisted so I had to cut through the middle fixing to rectify it.

standard m3 trumpets fit but it won't with the m3 plenum.
I'm gonna have to cut the trumpets down and make my own plenum the will use my oe m40 air box and afm.

[rix313]

This is cool

What sort of gains are you expecting? May I also ask roughly how much it's costing?

Just chatting crap outload here, is it worth fitting one of those long ITB air filters, making a decent cold air feed using some technicaly named 'donkey dick' piping and then raising the rear of the bonnet to help remove the hot air from the engine bay? Suppose it's more of a track car solution.

[tim_s]

Good work This brings back memeories. I never welded mine but made up some ally brackets to hold them down - yours is a better solution! I've tried these on a 1.8 before on some quite tasty trumpets, ITG socks, MS and kent cams. Results were ok, sound was a bit disappointing in some regards but was actually quite useable! They really are some huuuge TBs for the engine's capacity. What other bits you going to be using? What cams/management?

[Alburglar]

Filter socks or a universal filter and trumpets would simplify things greatly, but I'm not sure how to go about getting rid of the afm?

cams are standard at the minute. Plan to run it on my chipped ecu, at first and do a power run. I also have an MS ecu that a fellow zoner built into a standard m42 ecu case, so it'll plug straight in. However I've spent hours tracing the ms outputs to the relevant plug pins and some are either wrong or my plug or ms diagrams are wrong. He reckons he ran it with a supercharger for 2000 miles, so I will just have to trust him and plug it in. I will retro fit a lambdna first tho.

[tim_s]

That Ash's old megasquirt?
wrt the TBs, on standardish cams throttle response was good and it sounded fun, didn't make much power - the IS inlet is well designed and gives good response. On balance I don't think it was any better than on the factory inlet, did quite a bit of playing with trumpet length, but probably not enough.Never had it on the rollers, never really did that much mapping on it really. I did some basic mapping on it but then the owner had to remove them for a 'ring trip as the fuel rail had a drip where it had been welded Don't think they ever made it back onto the car after that.
Def will need spikey cams on a 1.8. As for the AFM, you're really going to have to give up on it for this conversion imo to get the most out of it. Chipped ECU god knows what that will do for you, you need to get it on some rollers. I used an SMT6 on mine for a bit, I could never get it to work properly though and their support was useless. Got as far as 'try a capacitor here' and when it didn't make any odds just a list of excuses and you'll have to fit bigger injectors. Reckon with persistence it could work though. For me it was lean on full load when I ahd the SMT fitted - am sure bigger injectors would cure it, and when I converted to MAP it wasn't that smooth even though I thought I had a good match of its output to the original AFM.
If I were to do it again and wanted an easy life I'd prob drop it into Paul Sheps at Circuit Motors and just have him fit a Uni-Q with a MAP sensor conversion.

My 2.1 was excellent on TBs, sounded like an absolute monster, throttle response was great, unfortunately with one thing and another they went on that engine too. Mainly cos my ex was driving it a bit and it was easier to drive on the standard inlet (is quite sensitive on the throttle pedal with the TBs), plus on the K&N cone filter I had it was a bit noisy on the motorway. Had some advantages though as eventually I went back to motronic...

[Alburglar]

Yeah his name was ashley. I think his tag was hoshy.
I will build a stroker eventually, so it'll all swap over.
Very happy with progress tonight. Cut out what I need from m3 air box.

drew round what was left, cut it out and bent it to fit

just need to find some 64mm ally tube to match up to M40 afm hose. This one is stainless, but it'll give you the idea of my end result.

new air box will be snug, but hopefully it will all fit in engine bay with OE e36 trumpets turned upside down (i think).

[Brian28]

Nice project

[Dave_M3]

Sweet!
Good progress there, nice to see somebody else following it through as its been a while since we've seen Tim's famous iS around the zone

I really shouldn't have bought another few E30s and kept at my 2.1 ITB build as the iS is looking very sad in the garage for the last few months
I was going to do the same idea with mine by welding both pairs together and building up the corners and re-drilling the holes.

Have a guy making a carbon airbox in all for me but think I'll use S54 ITBs now and sell on the B30 ones.

[rix313]

Hows this going?

[chips]

Great work. It's nice to see this being done properly, how I wanted. I think welding on new tabs is a much much better solution than a spacer plate.

[Dave_M3]

I found myself a set of S54 throttle bodies and pistons the other day

[Alburglar]

Finally got the air box welded:





But I've welded the inlet on the wrong side. Doh! what a tosser! But perhaps I can just turn the box round, we'll see.

It will be a while before I fit this tho cos I'm just finising my track car

[snooka]

great work, can you make one more

[e21Jason]

Nice work but that air box looks wrong, to narrow and all the bellmouths should have the same space in front of them rather than a taper

[Alburglar]

They all fit great and have load of space in front of them.
I might trial fit them this week to make sure it all fits, but will probably be selling the whole setup including the ECU. The touring now has to stay "tow car spec" because my really fast project car is nearly done now!
Admitadly the pic does look a bit deceptive.

[Dave_M3]

My Touring was going to have an M42 and was comptemplating throwing a set of ITBs I have for it on but then decided it would be better with an M52 for towing.

[chips]

I was the original owner of these throttle bodies. I sold them to Alburglar because I decided to look for an M60 to fit instead.

So who's going to finish them off?

[Alburglar]

They are finished, they just need injectors, that is all.

[Alburglar]

Sold, but thought I'd post some assembled pics, before I post them.

[Alburglar]

ecu is in the for sale section

[tim_s]

That plenum is tiny! :S

[rix313]

What're the requirements for plenum volume then Tim?

[tim_s]

I wouldn't want to be too prescriptive on plenum volume, but basically you want to be mimicking atmospheric and not causing any turbulence or pressure diffs across cyls, so more or less you want as big as you can cram in within reasonable limits! As guidance a standard BMW one taking the smaller engine capacity into account is at an eyeballed guess circa 3 times the volume of this one here. Also intrigued on trumpet length on this set up, with huge 50mm tbs and a 1.8l engine, runners must be v long. I had trouble getting decent results on a 1.8 with s50 tbs. Got on well with the 2.1 though

[Jhonno]

Yeah, the plenum looks waaaay too small to work properly unfortunately.

[Alburglar]

Yeah - but it's a parts pin build with no extra money being spent and it will work fine. Grabbing an extra 3bhp was not top of the list on this build fellas

[tim_s]

Spose, prob with that kind of approach with those tbs is that if you're not careful making worse power than standard is a distinct possibility, not to mention the other drawbacks of changing to s50 tbs such as the pedal feel. Then again I'm not much better, tried the bypass mod on the boxster zorst today with 1.5" pipe as recommended, ended up driving it a few miles then taking it off again as it was so damn loud, total waste of time! Still, nothing ventured, nothing gained etc and it would def be intriguing to see how it performs on those tbs...

[HairyScreech]

generally suggested that plenum size is 0.8 to 1.5 times the engine capacity as only one runner should be drawing on the plenum at any one time.

ill look it up and be more specific.

[Alburglar]

That is useful. So you could go for 1:1 ratio so a 1.8 engine would need 1.8 litres of plenum space

[rix313]

I'd have thought a minimum twice the area, if you think how many cycles the engine is going through, that's alot of air to suck and have to replace.

[Dave_M3]

There's a lot more volume than 3L in an S50 plenum anyway, thats for sure!