ITB Project

[JazzMan]

I've been toying with the idea of ITB's for a while so I've started using throttle bodies from a GSXR 600 K3, here's my progress so far:

Two sets of these GSXR 600 K3 throttle bodies:



A spare M20B25 intake manifold



A number of hours with a hack saw, angle grinder and piller drill on the lathe with a milling bit later:



And you get a nice manifold ready for some ali tubes to be welded on:



The manifold will slot right on being the mounting face of a stock intake as can be seen below:



The nice thing is that the provision for the oil return is already integrated to there's not need to come up with a solution for that:



The stock fuel injection locations will be used, those on the GSXR will be plugged.



The GSXR individual throttles need spacing further out than that standard so some modification will be required to make this work. The K3's have a second set of throttle butterflys controlled by the ECU, these will need removing and the extra holes plugging. The end piece as a TPS integrated. The diameter of the GSXR bodies is 38mm at the engine side, they are tapered and open up a bit more to the intake side. Based on what I've read on the Zone.

The plan is to use tubing to connect the throttles to the manifold so that its possible change the lengths and see what the does to the power!

[oakey]

Good work man!

[zaust]

And your working in the kitchen !!!

Look's like a tight fit for the tb's to manifold, Is there enough meat for them to fasten into the manifold ?

[JazzMan]

I've ordered some ali tube that I will cut to shape (and the right angle) which the throttle bodies will attach to with silicon pipe. I'll be able to vary the distance from the engine as needed

That's actually the workshop, but fitted with kitchen cabinets as it doubles as a bedroom at night!

[appletree]

Great work, they realy do look the nuts when there all lined up like that!

Dont forget to get silicone that can cope with the oil/petrol i struggled but got some in the end from a place called harworth hoses thats local to m e so if you can't find any let me know and i'll go and see him

[CptKirk]

Hi,
Been thinking of going down this route with my 325i sport that I prepped last year for hill climbs and sprints, did a few events last year but want to improve the car as I go along.
Do you know anyone that's done something simular to you? or even fitted 3x webber 45's to a modified intake maifold?, any idea as to bhp gains once fitted? be interested in following your progress.
Regards
David

http://davidkirkbmw.blogspot.com/

[JazzMan]

there's number of people who've done ITB's on their car, if you search for ITB on the forum there's quite a number of threads on the subject.

If you want something out of the box a German company called dbilas (http://www.dbilas-dynamic.de/) make bolt on ones but that obviously more costly than DIYing it. IIRC Dbilas claim 20bhp but I would guess this depends on what else you've done to the engine.

While searching around I saw a South African company that made manifolds for carbs. I'll see if I can find the link again.

EDIT: Couldn't find the the S.A. one but found one in the US: http://www.extrudabody.biz/servlet/the- ... ple/Detail

[zaust]

I'd been thinking about this on the m30 but had ruled it out. Now you got me thinking again.

[CptKirk]

Great, Thanks
All the best
Happy new year
DK

[BadDave]

Hi,
Been thinking of going down this route with my 325i sport that I prepped last year for hill climbs and sprints, did a few events last year but want to improve the car as I go along.
Do you know anyone that's done something simular to you? or even fitted 3x webber 45's to a modified intake maifold?, any idea as to bhp gains once fitted? be interested in following your progress.
Regards
David

There's an inlet manifold currently on ebay at the moment with a £300 starting price which should work with webber 45's or weber type throttle bodies from companies such as jenvey

[BadDave]

E21jason has a set of side draught weber's fitted to his 2.7 with a griffin m/sport manifold

Rally design list a manifold for the M20 but i've heard it's for downdraught carbs.
A quick phone call to them,would confirm as to whether that's correct or if it's a load of rubbish

[CptKirk]

Thanks again, I'll take a look and give em a call

DK

[JazzMan]

A small bit of progress today:


Two sets of ITB's give you 4 bolts to screw them together - not long enough for 6 throttles. The solution is to chop the thread off two of them and the head off the other two. Then the 4 bits are welded together to create two long bolts.


After welding the join is ground down to make it round and smooth.



Which means with temporary spacers its all one piece now

[tomson]

Looking very good !!!

[cliffybabe]

they look wicked , I really wish i could weld

[JazzMan]

Thanks

they look wicked , I really wish i could weld

Richards the one that can weld, I taught him everything I know from watching people weld on TV

I've just not had much practice.

Next big task is figuring out how to weld ali properly with the mig - Tig is just too expensive to justify for a one off project.

[cliffybabe]

are u using gasless mig??

[Jon_Bmw]

A great standard of work as always Jazzman.

[JazzMan]

are u using gasless mig??

Nope, got a bottle of argon for ali welding and a reel of suitable wire Not sure it'll look to great. Will do a lot of testing first.

[diogogaspar]

outstanding job there mate, and correct me if I'm wrong but since k3 gixxers don't have the extra set of unjectors for midrange response it's an "easier" conversion.

Top Job there mate

[Phill172]

Porno!

Exactly what i was going to do!!!! Iv still got the old manifold cut!

You doing the welding of the ally tubes yourself or is it going off to someone else??

I spoke to bogg brothers about this, an they seemed pretty content that i would work fine an quite liked the idea!

Although iv put a set of these on a Renault K4R Motor in a old twingo and iv found that the throttle pedal is really short

But still quality work mate!

[JazzMan]

outstanding job there mate, and correct me if I'm wrong but since k3 gixxers don't have the extra set of unjectors for midrange response it's an "easier" conversion.

Top Job there mate

Yeah, its a K3 so I still have to plug up the holes for the secondary butterfly's but that's not a big problem.

Porno!

Exactly what i was going to do!!!! Iv still got the old manifold cut!

You doing the welding of the ally tubes yourself or is it going off to someone else??

I spoke to bogg brothers about this, an they seemed pretty content that i would work fine an quite liked the idea!

Although iv put a set of these on a Renault K4R Motor in a old twingo and iv found that the throttle pedal is really short

But still quality work mate!

Well I've got plenty of left over manifold and lots of ali tube coming so I shall be giving it a go (and my brother will be too) on some test pieces. If it works nice we'll do it, if not I'll find somebody to do it for me

[e30_Turbo]

Welding the ali runners to the flange is the only part I can't do, ow that and drill 50mm holes!

Ow and weld stainless, so overall I'm crap

My local heavy engineering company are milling the holes and the oem flange down, local movie stunt company I work with have a full time welder who's gonna finish the whole job for me, I will get some practice in on something not quite so obvious in the engine bay

[JazzMan]

^^ Nice


I've been research idle control on these. The GSXR has a manual fast idle lever on the bar. Some people have experimented with a stepper motor to control this, but I think I'll probably employ the solution that BMW themselves use on the M3's - a common vac pipe connecting all 6 cylinders and a standard ICV bolted up to it. I can use the second set of injector holes that are directly on the throttle body.

[ShakeyC]

Exactly how I would do it too saves hassle of fabricating an adapter manifold. With the idle theres some bleed holes manifold side, bottom of the throttle bodies connect them all up with T pieces to create a vacuum balance. Remove the secondary butterflys blocking all associated holes, remove the box end of it too its of no use. As your not using GSXR injectors with some larger vacuum hoses connect empty injector holes up together with take off for brake servo.

Depending on port spacing extend the little tabs inbetween each throttle body retaining the OE screw and spring adjustment as you will need adjustment to make sure they all open at the same rate. For manual idle control simply adjust the throttle stop screw to set idle base crude but it works.

Hope that helps

[JazzMan]

Exactly how I would do it too saves hassle of fabricating an adapter manifold. With the idle theres some bleed holes manifold side, bottom of the throttle bodies connect them all up with T pieces to create a vacuum balance. Remove the secondary butterflys blocking all associated holes, remove the box end of it too its of no use. As your not using GSXR injectors with some larger vacuum hoses connect empty injector holes up together with take off for brake servo.

Depending on port spacing extend the little tabs inbetween each throttle body retaining the OE screw and spring adjustment as you will need adjustment to make sure they all open at the same rate. For manual idle control simply adjust the throttle stop screw to set idle base crude but it works.

Hope that helps

I'm not sure the bleed holes will be big enough for idle? I was planning to use those for the MAP sensor as the bike does.

I've seen lots of people running the servo off just one cylinder without any problems.

The throttles a chunk further apart so I need either make new fingers or extend the existing ones so they all link together.

[ShakeyC]

I should have wrote it differently, I ment idle holes all T together and idle is set by throttle stop screw which sets how far the butterflies closes, more open/angle the throttle plates rests dictates what rpm idle is.

No reason why not to use throttle bleed holes as map sensor feed too if thats the way you wish to map it using both tps and map sensors. Again you can run brake servo off one cylinder if you wish no difference really apart from aesthetics.

[JazzMan]

ah ok cool

[Turbo-Brown]

My mate's idle rises by about 200rpm with a 4mm hole drilled into each runner. We've literally just ordered an IACV for it actually as he's tired of having to keep the engine alive on the throttle when the weather's cold.

It's something I'd definately recommend, and IACV. Makes life so much easier!

You can run the servo off just one pot, but it gives the diaphragm in the servo a hard life (unless perhaps you use very small bore pipe to it) It's much better to connect all the throttles together on a common rail as Shakey says, and drive the servo off that, plus allowing an IACV to be incorporated.

I also wouldn't bother using a MAP sensor at all. Just run with a throttle pot.

Both MAP based load and throttle angle based load work on assumptions and neither is really a better way of doing it unless you're running ITBs in which case the steadyness of the signal from a TPS is hard to beat.

[maggspower]

Hay man cool project!!

This is going to be one pokey m20b28, You should really put it back in a beemer

I'm sure you've done your home work on the welding front, but heres a few tips, as mig ali welding can be a pain in the ass.

Teflon coated wire liner, don't tangle the line between the torch and the welder, keep it as straight as possible while welding. Get an oversize tip, so if you are using 0.8 wire get a 1.0 tip, I just drill mine. The above helps the wire to run smoothly as the ali wire grips stuff giving feed problems.

You will need loads more wire speed than with steel, this means you will have to work very quickly, and means that mig is only realy suitable for thick stuff, but i reckon you'll be ok on that front.

The most important thing is cleaning back to bare metal as ali can absorb impuritys and oxidises very quickly, get yourself a new stainless wire brush, use it on the bit to be welded just before you put your mask down.

Hope I don't sound too patronising I just know how frustrating this process can be.

Good luck

[JazzMan]

Thanks for the welding tips, very helpful

I've got a ICV from an M42 - 2 pin type knocking about and also the M20 one. The throttle bodies have a TPS pot built in to one of the end ones, so I'll use that

[JazzMan]

A bit more progress today in preparation so the manifold can be completed. I couldn't quite run the pipes at the same angle as the holes in the head due to using the stock manifold. I've opted for a shallower angle that will result in a relatively smooth transition between the pipes, manifold and head. I could always completely custom make a manifold at some point in the future.
The other big step was to get the throttle bodies properly spaced. I cut 10 spacers on the lathe exactly 11mm wide. There still a lot to including the minor issue of welding the pipes on - not sure how this will work but I suspect it will involve doing a lot of grinding to clean it up!



Ali tubes cut



Quick test fit



"just" needs to be welded!



And from the other side (yeah the throttles are the wrong way round ;o) )



Spacers cut on the lathe to space each throttle 11mm wider than they are on the GSXR

[Turbo-Brown]

Looking awesome

Think if it were me, I'd not bother welding the throttles to anything though for fear of warping (or have I got the wrong end of the stick there!)

Be interested to see what you do about the linkage for the throttles too.

Personally, I'm not a fan of extending all the fingers on the bike throttles. It's all just too bendy and the possibility of having the throttles near the cable opening and the rest opening later is quite high.

Also interested to see how you deal with the progression off closed throttle.

Obviously if you just connect the throttle cable to the bike throttle's yoke you'll get full throttle if you just look at the accelerator pedal.

Having the throttles open progressively is really important for drivability (sure you know this already!) having them open maybe 30% for the first half of pedal travel, and then end doing their last 70% of opening in the last half of pedal travel (just plucking at figures there but they're probably reasonable ball-parks) would make the car nice to drive I reckon

[JazzMan]

I meant welding the ali pipes to the manifold, I'll use the blue pipe to connect the throttles to it I suspect my brother Richard will probably attempt the welding as he's a lot better at it than me. We've not done much ali welding at all yet, just patched a hole in the Sportster fuel tank so far.

I was going to try extending the fingers first, should be OK if they are stuff enough. I'll need to disassemble each throttle so the little rubber bushes don't melt when I weld bit on. The fingers themselves look like the have been fitten and the metal crushed to keep them on, so I can't just make new fingers the right size and put them on.

With regards to the throttle pedal I've not thought that bit through yet, but I've seen progressive stuff mentioned (I tend to do this stuff by dealing with each problem as I get to it -> I see the end result and just deal with the issues as I go, I think that's what 3 years of kit car building does to you ).

I figured if there's enough movement at the foot end of the pedal vs the throttle open it might be OK, if not I'll work on alternate solution

[diogogaspar]

sorry to say this but I'm going to kiddnap you and make you work for me in a dar and moist cave where the sun doesn't ever shines