S14 TBs on an M10

[Lee]

While I am waiting for the next batch of parts from the CNC shop, I have been bouncing the idea of making strong throttle bodies for an M10 motor. I started measuring how long the S14 intake is: 6" or 2 inches shorter than Webers + intake manifold. To fit S14 TBs onto an M10 motor, all I have to do will be to chop 1/4" off the TB's flange, have some M10 intake flanges cut from 1/2" aluminum, weld them together and port them for smooth finish and great flow. Then, I can bolt a fiberglass or CF DTM airbox for fresh air.

TWM TBs are $700/pair + fuel rail + regulator, or about $1100. I will make my TBs for under $250 and they will be stronger.

S14 and M10 have the same cylinder spacing of 100mm. The S14 TPS would maybe be in the way of the alternator. I just need to lower it a bit and I should be in business. TBs are 46mm in diameter, so it will fit the M10 head properly. I will let you soon how it develops.

[winstontj]

Count me in - if you need a deposit give me an address!

[PSloan]

I dont think he's selling them - just making a pair for himself.

[Lee]

I dont think he's selling them - just making a pair for himself.

Exact. This is just personal development. If it works, then everyone will have the opportunity to make their own.

[TobyB]

hell, even if it doesn't, you could always do it anyway...

har har...

t

[dhs]

Lee,

I had planned (and still do someday) to do the same thing. I looked hard at this a while ago. First looking at adapter plates. That was problematic because of the amount of port/tb shape change in a very short space, bad for flow.

In the same spirit, I think you will find that 1/4" removed will not give you a good match in port to tb shape. As I am sure you have noticed, the s14 tbs exits are wide and short. M10 head port is tall and narrower. If you cut off more of the s14 tb the shape gets much closer. It would still will require grinding and possibly metal addition to avoid grinding through.

I am confident it is a sound idea if you or someone you know has the skills and tools. FWIW I was going to use a 318 manifold for the m10 side of the 'new' tbs retaining the same amount of length as would be removed from the s14 tbs.

Very interested to see what you find out!

[2590402]

Please add me to the list!!!

[Lee]

Hi David

You are entirely right in your assessement that the port on the S14 TBs are wider than the M10 inlets. My intention is to chop about 2" from the TBs and butt weld a piece of 2" tubing, then squash the section near the flange.

Most likely, a 2" (50,8mm) OD aluminum tube should have about 46mm ID. That's about 2,4mm wall thickness for the aluminum tubes. The other solution is to generously add welding and extensively port the base of the TBs.

The reason for choosing S14 TBs is that they are very well made and strong. Adjustments are very stable.

[Lee]

Please add me to the list!!!

There will be no list. It is "only" personal development.

If it works, others will be able to replicate this development, and save $$$ ovet TWM ITBs.

[Guest Anonymous]

The reason for choosing S14 TBs is that they are very well made and strong. Adjustments are very stable.

And very heavy...I looked at this but I think you would need to build a brace for sure.

Let me know how it goes.

Anthony

[Lee]

And very heavy...I looked at this but I think you would need to build a brace for sure.

Let me know how it goes.

Anthony

Indeed, they are heavy and will need a brace, just as Webers do. BTW Anthony, the 48 DCO/SPs worked great last weekend, except for the usual problem of de-synchronizing, which is traced to the lack of double-nut, or spring on the synchro screw. Big 65 idle jet works great. Will also increase acceleration jets from 45 to 50.

[dapbmw]

the guys in finland did it on the 500 hp 1502 turbo

[MOESPEED2002]

Hey Lee......

Those TB's are interesting. Are they from an S14? I have never seen them attach to a head like that. Usually, the TB has 4 bolts per runner to attach a TB Gasket, then the TB gasket attaches to the head with three bolts, like in the picture. Interesting.

I saw that you were looking for a set of 46 TB's. Now I see your master plan. I know that you have both motors to take measurements from, but if you need help, let me know.

Good luck with your plans.

MOE

[Lee]

Hi Moe

The throttle bodies pictured in the first thread are not exactly 46mm ones. They are 50mm TBs from the e34 M5. They don't use a rubber gasket like on the S14, but bolt straight onto the head.

[peteinjp]

Of course it seems that the transition should be gradual but tonight I was looking at my s14 exhaust header- holy transition batman. I think there is room to get it nice enough. I thought you were planning to put the s14 in?

BTW- do you have any exhaust flanges left for the stock s14 header?