e30 m30 + OEM ITB test fit

[Jb325is]

I haven't posted much since I finished my swap/ms conversion, but the car is finally running pretty smoothly. It has a couple issues like inconsistent idle (speed density + 290 cam, not easy) and it breaks up over 5k rpm a bit, but overall it is much faster and easier to drive than on motronic. Anyways, got these throttle body adapters through a friend of a friend, just about to start messing with them to see what it's going to take to get them to work.

Quick mock up with the adapters-






The thermostat housing outlet will definitely need to be modified, and the intake ports will need to be machined. I need to order all of the linkage/fuel rail parts to see what needs to be done there but it all looks fairly manageable from the research I've done. I think I'll probably run velocity stacks and filters at first, and look into building a plenum as a long term goal.

The car still looks about to same




A couple auto-x pics (taken by Shawn D)





Here's dad losing it


I'll keep this thread updated with progess on the itb's for those who are interested

[Anguz]

very very nice

[kronus]

S38 ITBs?

[Jb325is]

Yep, I think they're off an e28 but I'm not 100% positive..

[Good & Tight]

That adapter looks top notch! That engine is going to rev so much faster.
Not sure if you read up on MS w/itb's but you should make a vacuum canister to connect all of them to get a clean MAP signal. Had to do this on my M10 w/itb's.

[Jb325is]

That adapter looks top notch! That engine is going to rev so much faster.
Not sure if you read up on MS w/itb's but you should make a vacuum canister to connect all of them to get a clean MAP signal. Had to do this on my M10 w/itb's.

Yeah I've read up on it a bit, I was thinking about changing to alpha numeric, but I guess you're talking about blended alpha N/speed density? The adapter is pretty nice, cost me $150 which I thought was pretty reasonable

[Good & Tight]

Yeah I've read up on it a bit, I was thinking about changing to alpha numeric, but I guess you're talking about blended alpha N/speed density? The adapter is pretty nice, cost me $150 which I thought was pretty reasonable

Mine was blended tps/map on boost though. Your na so alpha N should do the trick.
Once you get it dialed in throttle response is going to be so crisp. These are going on the big bore you put together right?

[Jb325is]

Yep, sure are. That's mainly what I'm after. I just had these throttle bodies laying around and stumbled upon the adapters, so I figured I'd see what happens

[dannyyisntt]

Subscribed. I like this idea and want to see where this goes...

[e30m3s54turbo]

Nice! I seen those on a e9 at a bmw shop. They to have to mod. the thermostat an run ms.

[Massive Lee]

M10, M30, S14 and S38 share the same 100mm bore spacing. Great for swapping parts. Keep in mind that the M30 is a low end torque motor, unless you start swapping cam (like the Hartge motors, per exemple). The ITBs now have a much shorter intake path than the original manifold. Great for high revs, but very detrimental to the low end torque. Keep in mind the Helmholtz resonance effect. The shorter valve-to-butterfly distance will raise the resonance frequency (RPM). You can help fill the intake with much longer airhorns. Trying adapting the S14 trumpets...

[Jb325is]

M10, M30, S14 and S38 share the same 100mm bore spacing. Great for swapping parts. Keep in mind that the M30 is a low end torque motor, unless you start swapping cam (like the Hartge motors, per exemple). The ITBs now have a much shorter intake path than the original manifold. Great for high revs, but very detrimental to the low end torque. Keep in mind the Helmholtz resonance effect. The shorter valve-to-butterfly distance will raise the resonance frequency (RPM). You can help fill the intake with much longer airhorns. Trying adapting the S14 trumpets...

Yeah I've looked into resonance tuning a bit.. I know that I have a lot of work to do determining proper length for the air horns. I've found a few companies that make them and the dimensions for the throttle bodies seem to be pretty standard so there are lots of options. This engine is 10.5:1 with a 290 cam, it's already pretty peaky as far as m30's go

[dsobering47]

thats hot. what suspension setup are you running?

[Jb325is]

550/750 Ground Controls

[JTDay]

Awesome! Subscribed.