Post your ITB Setup

[Mr Beau]

One comment I read said the BMW on was "good" because it was designed to handle 6 return springs. Don't know if there's any truth to that. I did come across a comparison table of some DBW actuators (torque, speed etc) but can't find it now.

[Pork Chops]

Angle grinder, tape measure, verniers, drilll, files and 2mm aluminium plate. Ist’s not perfect but it’s going to do the job. Only thing with the orientation of the actuator is keeping the loom out of the way of the actuator rod.

[Pork Chops]

[winders]

Flip it around 180 degrees and shorten the rod....

[Pork Chops]

Originally Posted by winders

Flip it around 180 degrees and shorten the rod....

I started there and there are some packaging issues with that too. For me I think this orientation will work well. Just need to see the loom in place to be 100% ��

[winders]

As you can see in the photo of my setup, the connector for the wiring harness is right below the arms on both DBW actuators. It’s not a problem with judicious use of zip ties.

[Pork Chops]

Originally Posted by winders

As you can see in the photo of my setup, the connector for the wiring harness is right below the arms on both DBW actuators. It’s not a problem with judicious use of zip ties.

Amazing how many times zip ties are the answer!

[winders]

Originally Posted by Pork Chops

Amazing how many times zip ties are the answer!

[zaphodtheprez]

I find the great benefit of the DBW setup with ITBs is the scaled progressive throttle response curve that can be programmed in at the ECU. It can smooth out low speed / low RPM driving and add in the the aggressive response deeper in the pedal where it's needed and appreciated.

[montauk]

Originally Posted by winders

I've mocked up a cardboard template for the throttle motor. I think I'd like to make one platform for the throttle motor and vacuum line collector. I'm planning on attaching it to the three studs for the original throttle shaft assembly and two bolts on the side of the intake manifold. These are the same bolts that hold the throttle cross bar. I may need to tie to one or two of the studs on the breather too.

Scott - I see that your throttle motor bracket attaches to the two rear breather bolts. Where else does it attach? I like the twin setup.

BTW, if anyone else is taking this route, this 6 wire throttle position sensor fits the BMW throttle motor.

https://www.digikey.com/en/products/detail/variohm/EURO-XPD-2832-812-214-911-00/22286984?so=90135047&content=productdetail_US

[winders]

Originally Posted by montauk

Scott - I see that your throttle motor bracket attaches to the two rear breather bolts. Where else does it attach? I like the twin setup.

There are two press fit dowel pins along with the two breather studs. The two breather studs are actually enough to hold the motors and the bracket in place. The holes in the bracket were purposely drilled just big enough for the studs so there is almost no free play. The dowel pins are present to locate the bracket on the cover and to prevent movement. The forces applied operating the ITBs are not enough to move anything.

The twin DBW motor setup is the best way to go especially since we are using the throttle position sensors in the DBW motors. Not using all the extra linkages required for a bell crank setup as needed with a single DBW motor setup is a very good thing. It’s much easier to setup each bank individually as there is less slop to start with and there are far less linkages to get sloppy or out of adjustment and PID setup is easier/better.

My tuner (works for an IMSA GTP Championship team) basically insisted on the 2 motor setup because of his experience with single motor setups on 2-bank engines.

[montauk]

Originally Posted by winders

There are two press fit dowel pins along with the two breather studs. The two breather studs are actually enough to hold the motors and the bracket in place. The holes in the bracket were purposely drilled just big enough for the studs so there is almost no free play. The dowel pins are present to locate the bracket on the cover and to prevent movement. The forces applied operating the ITBs are not enough to move anything.

The twin DBW motor setup is the best way to go especially since we are using the throttle position sensors in the DBW motors. Not using all the extra linkages required for a bell crank setup as needed with a single DBW motor setup is a very good thing. It’s much easier to setup each bank individually as there is less slop to start with and there are far less linkages to get sloppy or out of adjustment and PID setup is easier/better.

My tuner (works for an IMSA GTP Championship team) basically insisted on the 2 motor setup because of his experience with single motor setups on 2-bank engines.

Thanks Scott. I agree. Your setup is the better way to go. Unfortunately, with the PMO ITB's, there's no easy way to use two throttle motors without a lot of extra work. I suppose I could attach levers to the throttle shafts between the ITB bodies but at this point, I'll stay with it as it is.

[IS300]

finally, ups and downs its running great! my 82SC....

178 buff horses ... woohoo

[Phil1980]

Looking good, I like the amber rain covers!

Are they PMO ITBs?

[montauk]

I've cobbled together a plate to hold the throttle motor. In the photo, the motor is just laying on the plate. I don't think I'll cut the plate to fit the belly of the throttle motor. I think I'll put it on stand offs. I've got quite a bit more work to do on the plate to clean it up like welding the corners and adding a rib for strength to the underside.

I left extra space on the plate for the vacuum manifold.

BTW, I had to remove the arm on the throttle motor and put it back on 180°. I also disabled the return spring on it. With the setup shown, the throttle motor rotates 20° more than needed to get full motion for the throttle arm. I'm planning to leave about 10° of motion at both ends and never rotate the throttle motor to it's limits. Make sense?

[Pork Chops]

Originally Posted by montauk

Thanks Scott. I agree. Your setup is the better way to go. Unfortunately, with the PMO ITB's, there's no easy way to use two throttle motors without a lot of extra work. I suppose I could attach levers to the throttle shafts between the ITB bodies but at this point, I'll stay with it as it is.

Having just fitted a single motor to my PMO set up I cannot see how 2 would be required. Like you say it would in fact be very hard to package even if you decided it was best to go that way. And not to mention it’s far more expensive. You can always run a Clewett TPS as well as a single motor (with its own TPS).

[winders]

Originally Posted by Pork Chops

Having just fitted a single motor to my PMO set up I cannot see how 2 would be required. Like you say it would in fact be very hard to package even if you decided it was best to go that way. And not to mention it’s far more expensive. You can always run a Clewett TPS as well as a single motor (with its own TPS).

The PMO setup has never been a favorite of mine. The only reason I would ever select those ITBs would be if I needed that particular period look. There are MUCH better ITBs out there from a variety of sources. I prefer the AT Power ITBs as I prefer the benefits of the shaftless butterfly design (higher intake air velocity for any given air volume requirement which results in more power and torque). Plus they look super sexy. Finally, the PMO linkage setup is not great. The AT Power setup, for example, is much less likely to fall out of adjustment and is more precise.

Again, using the two DBW motor setup with most ITBs eliminates all the bell crank linkages and connects to the ITBs directly via a rod with rod ends. All super precise and with even lower chances of falling out of adjustment. Yes, it could be viewed as over kill but professional experience tells me otherwise.

In my case (a race engine in a race car), I was looking for the most power along with the highest reliability. So the extra cost was not really a factor. You, in your situation, may have less demanding requirements.

[Matt Romanowski]

Originally Posted by Pork Chops

Having just fitted a single motor to my PMO set up I cannot see how 2 would be required. Like you say it would in fact be very hard to package even if you decided it was best to go that way. And not to mention it’s far more expensive. You can always run a Clewett TPS as well as a single motor (with its own TPS).

I don't have personal experience, but I've always seen multiple motors on engines with mutliple banks of ITBs. The photo of the GM LMDh engine with the two Kinsler dbw motors is the one that always sticks out to me.

[montauk]

I was able to achieve a bit of a milestone, for me at least. My DBW setup is working. I wanted to make sure the DBW worked before I did anything else so I bought a Deutsch connector kit and dug up my old Daniels crimper.

I made a few mistakes. Number one, I hooked up the pedal connector incorrectly twice. The first time, I had the wrong pinouts. The correct pinouts can be found here.
https://openinverter.org/wiki/BMW_Electronic_Throttle_Pedal

When I remade the connector, I had my 1 2 3 4 5 6 backwards because I was thinking about the wrong side of the connector. I imagine I'll make that mistake again. For now I'm trying to make sure I look at the numbers by looking into the socket side not the plug side.

My next mistake was forgetting that the hall effect position sensor must be mounted correctly. The D socket is free to rotate 360° but if you put it on 180° wrong, it essentially reads high and low only. There's no linear output and it won't calibrate. It's wrong in this photo.


With it installed the right way, it calibrates perfectly. It's correctly oriented in this photo.


With that done, I was able to control the throttles with the pedal. FYI, I bought the pedal used for about $30 and the throttle motor for about $225. My mounting plate works fine and leave me enough room for the vacuum manifold but it's ugly so I may take it out and make another one.

So far, I've found the Haltech hardware and software to be easy to work with. The wires are all color coded and bundled neatly. Each bundle is labeled so it easy to find what you're looking for which is good because there are a ton of wires.

[Matt Romanowski]

Originally Posted by montauk

When I remade the connector, I had my 1 2 3 4 5 6 backwards because I was thinking about the wrong side of the connector. I imagine I'll make that mistake again. For now I'm trying to make sure I look at the numbers by looking into the socket side not the plug side.

DT and DTM connectors are labeled correctly at the insertion point. The AS line are labeled as well, but not with every pin.