ITB M42

[MLM 57]

Are you making your own merge collector

Was thinking of buying one from auto bend as a base then adding my own venturi. Their collectors seem well made and probably better than i could achieve anyway.

[MLM 57]

This is the final Primary layout which fits ok. Lengths are near equal with a range of 40mm from shortest to longest (wider torque spread?). Also included a photo of the factory layout as a comparison.

The length range is somthing like 300mm from factory with one primary 120mm long and another over 400mm long.

[No name user 379]

what diid you base the header length on

[MLM 57]

what diid you base the header length on

P=(850*ED/RPM) -3 from the book: Four stroke performance tuning by A.Graham Bell

Also used his calcs for Primary/secondary/tailpipe ID

[pvl 0]

this is awesome stuff!

i'm planning on building an airbox somewhere in the near future. i know a composites manufacturer who has made airboxes for bmw's WTCC and ETCC projects, so i'm hoping i can use those molds.

have you got any updates? (and more pics )

cheers from holland

[MLM 57]

Hi Peter,

No updates just yet, things have been busy as i am now engaged and have just bought a house so priorities have been elsewhere for a while. The project is still going though. I have driven it with the new air box and it goes well. The exhaust manifold is turning out far harder than i anticipated but i think I have got a good arrangement now. Trying to pack in equall lengths into the space is a challenge. I hope to progress this soon with updates.

Your project sounds like it will be awesome, access to wtcc and etcc parts and hopefully some advice will be a huge help to yourself. Post up your progress. It will be great to have some more international input.

[pvl 0]

getting settled really is a project killer isn't it

struggling with getting the cash to build up a new engine first with a ported head and bigger inlet valves. bimmer parts are pretty expensive....

had to weld up my whole car aswell, the thing was pretty rusty unfortunatly. took a lot of time offcourse.

my friends nicknamed it 'the crusty crab'.

i'll try to post up some progress when i get to building an airbox, could take a while though...

i'm probably going for an airbox with 1 big throttle body, i'm thinking about a M30 one, those are pretty big. if it's good enough for 3.5 litres it should be sufficient for a 1.8 with some extra oumpf. should be a bit easier to get dialed in with the whole standalone system too. ITB's can be a pain to get properly synchonised i hear. measuring the vacuum in each of the inlets and all.

i can see why the exhaust header is such a pain, you guys have a steering column going right thru the spaghetti. our LHD headers are a lot better if you compare the two so we don't need to build a new one as quick as you guys for extra performance gains.

good luck with getting settled and keep us posted.

cheers

[hybrid 1044]

Yeah mate... RHD sucks for doing headers. Spent 1/2 my exhuast budget on getting around the colum and still retaining flow.

[No name user 379]

Yeah mate... RHD sucks for doing headers. Spent 1/2 my exhuast budget on getting around the colum and still retaining flow.

You can also run the headers forward then back under leaves tons of room to work with

[MLM 57]

Finally an afternoon in the garage.

Tacked and ready for final welding.

By far the biggest challenge to date!

[No name user 379]

Finally an afternoon in the garage.

Tacked and ready for final welding.

By far the biggest challenge to date!

you really need cams to make them worth while

[MLM 57]

True, they shouldnt be detrimantal though untill I can save up for cams and all the other bits and pieces that could go along with them.

[No name user 379]

True, they shouldnt be detrimantal though untill I can save up for cams and all the other bits and pieces that could go along with them.

let me if you want some

[MLM 57]

Will do, Thanks.

[hybrid 1044]

You can also run the headers forward then back under leaves tons of room to work with

Not it you want to keep the length and expansion chamber size the same on stock s50 headers. For these s50's in NA form messing with the pipes too much really buggers up the mid range. Unfortunately many have tried to improve on the design and in stock form haven't been able to tune them properly without giving way to some other compromise.

[No name user 379]

Not it you want to keep the length and expansion chamber size the same on stock s50 headers. For these s50's in NA form messing with the pipes too much really buggers up the mid range. Unfortunately many have tried to improve on the design and in stock form haven't been able to tune them properly without giving way to some other compromise.

header design and length is meant to be built around port flow/runner length and cam duration after BDC header design isnt just done cause thats how everyone does it, well not if you want good results thus if they suffer things like mid range maybe they left a few things out of that calculation.

headers are designed to work best at a set point before and after is a compromise also stepped primary's for 8-10" after the header flange gives a double power band as does 4-2-1 also the merge collectors internal design helps broaden the power band apart from that i have no idea what works best

Edited December 6, 2012 by crunchy

[hybrid 1044]

yeah, as it was I had to rotate and shave my 6, 1,2,3 from the block flanges. Managed to keep the stepped expansion chambers shape and length intact but my number 6 I had to do a few more angles to get it to the collector.

Have since found from data logging it hasn't messed with it too much as far as adpation compensation is going. But then again mines running too rich due it seems removing the emmisions pump and not running cats. Software is still stock. Must change that asap

[No name user 379]

yeah, as it was I had to rotate and shave my 6, 1,2,3 from the block flanges. Managed to keep the stepped expansion chambers shape and length intact but my number 6 I had to do a few more angles to get it to the collector.

Have since found from data logging it hasn't messed with it too much as far as adpation compensation is going. But then again mines running too rich due it seems removing the emmisions pump and not running cats. Software is still stock. Must change that asap

i always have a laugh when i see guys put aftermarket headers on their car and say it didnt make a lot of difference, gezzz i wonder why

[MLM 57]

Headers finish welded. Just need coating now.

Rest of system finished and painted.

Building headers was quite a challenge and not somthing im going to rush into again. Hope its worth it.

[MLM 57]

Had the headers coated this week.

Looks nice even and will keep away corrosion. Should help out thermally too. Hanging out now to get this all fitted and the car started. Should sound a bit different with the airbox and exhaust.

Edited June 12, 2013 by MLM

[Michael. 2313]

Awesome work.

Where did you get your headers coated, HPC?

I need to get mine done soon, starting to get a little rusty actually.

With your header design, did you incorporate any expansion joints?

Edited April 27, 2013 by Michael.

[MLM 57]

Pro coat did the headers with their "cermachrome" coating. I was going to go looking for a picture of your headers at some point to see how you dodged around the steering column.

As for expansion joints there are none, the header is all welded one piece.

[Michael. 2313]

Pro coat did the headers with their "cermachrome" coating. I was going to go looking for a picture of your headers at some point to see how you dodged around the steering column.

As for expansion joints there are none, the header is all welded one piece.

Looks good, does their coating offer any thermal protection?

Heres an under side shot, this runner clears the stock shaft by nearly 5.00mm, I have another shot from the top somewhere http://i133.photobucket.com/albums/q58/UZZ...344231273_n.jpg

Yeah mine are one piece too, I went for mild steel so it didn't seem to be such an issue.

[MLM 57]

Yes it does does though its not its main feature, or rather they also offer an out right thermal coating in black.

Thanks for the pic, I managed to get about 15mm minimum clearance to the steering with equal lengths hence the loopy shape.

[MLM 57]

All installed. Went together without any problems beyond access to a few nuts which was tight, but i knew this would be the case.

Clearance to the steering column is ample with no risk of hitting, may even be better than factory.

Underneath everthing tucks up nice and tidy.

Sound wise its louder but its hard to tell how loud with it reverberating in a garage. I will see how loud this works out to be when i drive it. At idle the note is low and bassy but when revved has a raspy quality to it. Again will see how it settles down as im not worried about the tone of the exhaust provided its not overly loud and performs well.

Almost time to put it on its wheels and see if all this effort amounted to anything besides alot of fun in the process.