Best standalone for ITB setup in 2025?

[rwest]

Originally Posted by JKarow08

In terms of added complexity, I see very little. If you want to run an IACV (I do), you need to run vacuum lines to a manifold anyway. Running one more to an on board MAP sensor is as simple as it gets, and the tuning is no more challenging than selecting a blended map strategy and tuning both individually at the appropriate RPM range, with some minor tweaking to the transition point.

It’s not as simple as that as I found, if you try and use the MAP vacuum circuit for both IAC and MAP signal, you basically have a huge vacuum leak during the warm up cycle. Maybe some ECUs have a warm up table and a running table for MAP?

[Joesmallwood]

Originally Posted by rwest

It’s not as simple as that as I found, if you try and use the MAP vacuum circuit for both IAC and MAP signal, you basically have a huge vacuum leak during the warm up cycle. Maybe some ECUs have a warm up table and a running table for MAP?

I dealt with this using megasquirt. MS3X has a separate VE table for idle that makes it a non issue. EMU Black, does not (that I have found). Not sure about other ECUs.

[rwest]

Originally Posted by Joesmallwood

I dealt with this using megasquirt. MS3X has a separate VE table for idle that makes it a non issue. EMU Black, does not (that I have found). Not sure about other ECUs.

Good information Joe, thanks.

Are you able to get a good cold start and drive off without any extra pedal input or messing around?

[JKarow08]

Originally Posted by rwest

It’s not as simple as that as I found, if you try and use the MAP vacuum circuit for both IAC and MAP signal, you basically have a huge vacuum leak during the warm up cycle. Maybe some ECUs have a warm up table and a running table for MAP?

All an IAC valve is is a controlled vacuum leak. All standalones capable of controlling a IAC (most) have a map to control the duty cycle in relation to engine temp, as it warms they close and allow less air in, slowly reducing the RPM through the warm up cycle. Using a blended table approach means you can base your idle table off of TPS when the IAC is open which can cause "fuzzy" MAP signals. When you open the throttle it can transition to speed density until the signal goes fuzzy again above 20% throttle or so. At least that is my understanding, this is my first adventure in ITBs, though I do have experience controlling an IAC with a standalone on a Subaru single throttle body setup.

[Joesmallwood]

Originally Posted by rwest

Good information Joe, thanks.

Are you able to get a good cold start and drive off without any extra pedal input or messing around?

When I was running MS3X, yes - as long the other corrections are reasonably accurate (IAT and CLT). I switched over to EMU Black last year and run TPS now. It's not an issue with TPS/Alpha-N either. Like mentioned earlier, I have been contemplating trying a TPS/MAP blend to help with the transient issues caused by the sudden rate of change when the butterflies start to open with ITBs. The curve is super steep. Scaling the axis helps, but I am still curious of a TPS/MAP blend would help dial in fueling in that transition. FWIW, it runs reasonably good as-is, but as others have stated, that tech is there, why not try it.

[mb911]

Originally Posted by Showdown

Another element to consider, that has been mentioned before is whether or not you're going to be tuning this yourself or paying someone. Something like Haltech has the ability to allow someone remotely log into the ECU and tune it which is really cool if you are building a super complex engine and anticipate issues... maybe not needed on more modest builds.

Megasquirt has a massive user base and active forums and is someone open source which may be helpful if you're going the DIY route.

I don't know much about the other brands. MoTec has been around forever and offers race-ready solutions which are pretty stunning in both engineering and cost...

If paying someone to tune it, I'd likely defer to their ECU of choice, particularly if they're a dealer and can provide aftermarket support...

And finally, you might want to consider (maybe not) if the ECU offers any outputs for accessories like gauges or displays... I know that a few of the ECU's (Megasquirt, MaxxECU) use a standard open source CANBUS protocol that enables anyone to receive data and use it as they wish. I'm not sure about the others and whether or not is proprietary or encrypted to their own products. Not necessarily a key factor but one to consider...

You never know when someone is going to develop a vintage 911-specific digital gauge for aftermarket ECUs that fits into the clock hole and blends in seamlessly with a hidden button while delivering 10 screens of customizable data on a high resolution anti-glare screen...

Also MS3ProMini can run sequential fuel and wasted COP spark, totally fine for a non-race motor.

100% agree with this. I run megasquirt using Webers are TBs in my 2.4 and it is night and day better than it was when using carbs. Car runs so much better and much better throttle response than I expected. It’s worth a look

[JKarow08]

Originally Posted by mb911

100% agree with this. I run megasquirt using Webers are TBs in my 2.4 and it is night and day better than it was when using carbs. Car runs so much better and much better throttle response than I expected. It’s worth a look

Ms3pro mini is absolutely the best value in standalones. For a lot of builds it is more than sufficient, and at $600 nothing else compares. If it had knock control I may have considered using one and going wasted spark, but with how detonation prone these heads are I really want that added level of protection.

I have a disease...I'm kind of an all or nothing type of guy. I'm currently living in Nicaragua and I have a '72 FJ40 that needed leaf spring bushings and had a seized drum brake cylinder...about $7k later it is about to have parabolic lift leaf springs and extended anti-inversion shackles, a Wilwood disk brake conversion, and an Aussie rear locker. I just can't help myself...if I'm going to wrench on something I go all the way, haven't been clinically diagnosed but I'm pretty sure I have a severe case of motorsports OCD

[TopTuning]

Originally Posted by JKarow08

Ms3pro mini is absolutely the best value in standalones. For a lot of builds it is more than sufficient, and at $600 nothing else compares. If it had knock control I may have considered using one and going wasted spark, but with how detonation prone these heads are I really want that added level of protection.

I have a disease...I'm kind of an all or nothing type of guy. I'm currently living in Nicaragua and I have a '72 FJ40 that needed leaf spring bushings and had a seized drum brake cylinder...about $7k later it is about to have parabolic lift leaf springs and extended anti-inversion shackles, a Wilwood disk brake conversion, and an Aussie rear locker. I just can't help myself...if I'm going to wrench on something I go all the way, haven't been clinically diagnosed but I'm pretty sure I have a severe case of motorsports OCD

Megasquirt is amazing for the price, but not a good system by any means vs advanced stuff.

Personally I'd never use it on a very expensive engine or anything I really wanted to run perfectly. The engine protection features alone on systems like MoTec M1 can really, really pay off.

That being said, I have micro squirt on my fuel injection converted motorcycle and it's pretty good. Bluetooth tuning is pretty rad.

[JKarow08]

Originally Posted by TopTuning

Megasquirt is amazing for the price, but not a good system by any means vs advanced stuff.

Personally I'd never use it on a very expensive engine or anything I really wanted to run perfectly. The engine protection features alone on systems like MoTec M1 can really, really pay off.

That being said, I have micro squirt on my fuel injection converted motorcycle and it's pretty good. Bluetooth tuning is pretty rad.

That's pretty much the only reason I didn't just go with a MS3pro evo...the features are there but I'm just not as confident in the support and it seems there are often more bugs to work out with megasquirts than the higher end systems. If a guy has some decent background knowledge and is willing to work through some issues, they are a great option though.

[winders]

Originally Posted by JKarow08

Take a deep breath, nobody is pi$$ing in your Cheerios here.

Can you make a solid tune on an ITB setup on TPS alone...absolutely. And you can make them run really well on carbs and a dizzy too. Are either the most advanced or effective methods in 2025...no. This is the same argument that is had over wasted spark vs full sequential ignition. Can you make them run great with no cam sensor on wasted spark...absolutely. Is it the most advanced solution today...absolutely not. Will the average person notice the difference on the average build...maybe not. But does that mean we should all revert to the simplest method of accomplishing a task? That's not how I operate.

In terms of added complexity, I see very little. If you want to run an IACV (I do), you need to run vacuum lines to a manifold anyway. Running one more to an on board MAP sensor is as simple as it gets, and the tuning is no more challenging than selecting a blended map strategy and tuning both individually at the appropriate RPM range, with some minor tweaking to the transition point.

There is a reason almost every current ITB kit include vacuum ports, and many include the vacuum manifold. Can they be tuned without it, sure, but in 2025 we have better options at our disposal. Build it how you want to...that's the fun of this hobby.

If you use DBW you don't need an IACV setup....keeps it all simple with a lot less to go wrong.....

[JKarow08]

Originally Posted by winders

If you use DBW you don't need an IACV setup....keeps it all simple with a lot less to go wrong.....

That is one of the things that has made me consider going with a DBW setup, along with simplifying the linkage and bank synchronization. It's a little more complicated in some respects but simpler in others.

[montauk]

Originally Posted by JKarow08

That is one of the things that has made me consider going with a DBW setup, along with simplifying the linkage and bank synchronization. It's a little more complicated in some respects but simpler in others.

I installed a drive-by-wire (DBW) system in my car, and it's working well during tests. I used a used BMW motor and pedal, creating a custom bracket that attaches to the three engine bell crank bolts, four breather bolts, and two bolts on the side of the throttle body. It's probably overkill. The brackets for the motor and pedal took quite a bit of time to make.

MegaSquirt hasn't fully embraced DBW yet. There's an extra module available, but I'm trying to avoid adding extra components. I like the all-in-one approach with the R3. I'm curious if DBW will improve the manifold absolute pressure (MAP) sensor's performance at low speeds since it doesn't rely on vacuum.

[TopTuning]

Originally Posted by JKarow08

That is one of the things that has made me consider going with a DBW setup, along with simplifying the linkage and bank synchronization. It's a little more complicated in some respects but simpler in others.

That's why my setup has NO LINKAGES or mechanical adjustments required

[JKarow08]

Originally Posted by TopTuning

That's why my setup has NO LINKAGES or mechanical adjustments required

Are there electronic adjustments that are necessary to balance the banks with DBW ITB setups? Any adjustments possible or necessary between throttles within a bank?

[TopTuning]

Originally Posted by JKarow08

Are there electronic adjustments that are necessary to balance the banks with DBW ITB setups? Any adjustments possible or necessary between throttles within a bank?

The setup is "one and done"

A throttle calibration is required, then set bypasses with a flow meter per cylinder to balance idle. Takes about 15 minutes.

I've never had to readjust anything on my test mule car, around 15k miles on it so far.