Turbo systems for X1/9's

[Bjorn Nilson]

I am checking sensors and triggers for my UT build and it seems like I must replace most of them as they are not compatible with with my modern engine management system. I also checked the supplementary air valve for cold starts. I put the valve in the freezer and it seemed to open up a little bit. Then I heated it up with a torch and it was slowly closing. Next test: When cold I put 12V to the valve connectors and it closed very slowly in 4-5 mins. But what is the last option good for? And how to connect it to the system? The UT ECU seems to read the cooling water temp and then trigger the valve (as well as injectors etc.) based on that information, but why? The valve works regardless of 12V power so is it really necessary to connect it to have the engine idling a little bit higher when cold? I can probably create a trigger in my MaxxECU to push 12V to the valve at a certain temp but what should it be good for?

 

[gene cooley]

I am checking sensors and triggers for my UT build and it seems like I must replace most of them as they are not compatible with with my modern engine management system. I also checked the supplementary air valve for cold starts. I put the valve in the freezer and it seemed to open up a little bit. Then I heated it up with a torch and it was slowly closing. Next test: When cold I put 12V to the valve connectors and it closed very slowly in 4-5 mins. But what is the last option good for? And how to connect it to the system? The UT ECU seems to read the cooling water temp and then trigger the valve (as well as injectors etc.) based on that information, but why? The valve works regardless of 12V power so is it really necessary to connect it to have the engine idling a little bit higher when cold? I can probably create a trigger in my MaxxECU to push 12V to the valve at a certain temp but what should it be good for?

It's possible that your "cold start" system is taken care of by your ECU without need for the original cold start/run system. It might be possible to just plug the cold start port and let the ECU take care of it internally.
If this is the case, there should be instructions on how to set up the parameters.
It's worth a read before you spend a lot of time setting up for something you no longer need.

 

[Bjorn Nilson]

It's possible that your "cold start" system is taken care of by your ECU without need for the original cold start/run system. It might be possible to just plug the cold start port and let the ECU take care of it internally.
If this is the case, there should be instructions on how to set up the parameters.
It's worth a read before you spend a lot of time setting up for something you no longer need.

Yes the ECU will handle it. But I probably need a new valve as the throttle is driven by wire. A valve with a fluctuating solenoid will most likely handle engine speed during cold starts and keep a steady idle also when alernator etc is creating load. The standard valve is not reacting fast enough.

 

[rachaeljf]

Hi Bjorn, if your ecu uses a drive-by-wire throttle it will control the idle speed without the need for a separate idle control valve.

The old Bosch AAV is very simple. It is energised all the time the injectors are energised. That is the only control the ecu has on it. It has a bi-metallic spring that gradually closes the air way as it is electrically warmed up over a few minutes, as you have found. The AAV also gets heat from the engine to operate the bi-metallic spring, so that when you start an already warm engine, the idle speed is not raised. This is why the valve should always be fixed to the head. Obviously in your case you don't need the AAV and as Gene says you can just blank off any idle bypass ports.

 

[gene cooley]

Yes the ECU will handle it. But I probably need a new valve as the throttle is driven by wire. A valve with a fluctuating solenoid will most likely handle engine speed during cold starts and keep a steady idle also when alernator etc is creating load. The standard valve is not reacting fast enough.

So, what I am assuming is just for cold starts also controls the idle circuit under normal conditions?

 

[Dr.Jeff]

I am checking sensors and triggers for my UT build and it seems like I must replace most of them as they are not compatible with with my modern engine management system.

I found the same information when I was researching my aftermarket ECU setup. The modern aftermarket units like to have modern sensors with parameters that they understand. There are several choices of commonly used items available very inexpensively that work excellent. For example here in America the sensors from General Motors vehicles (e.g. very common Chevy's, etc). See what the ECU maker's information suggests.

I also checked the supplementary air valve for cold starts.

As Rachael has stated, the stock Fiat AAV is a completely different type of cold start system than what the aftermarket ECU's use. On the stock system the AAV only allowed extra air, which then served to open the air flow meter (flapper) more and therefore richen the mixture (i.e. more air and more fuel). The modern ECU does not use the air flow meter so that system won't work - you would only get more air but not more fuel. Therefore you will not be able to use the Fiat valve.

There are a couple options: 1) Use the same ports that the AAV fit to and install a PWM idle control valve from another vehicle in its place (VW units are common), and program the ECU to richen the fuel when the idle control valve is opened (also by the ECU). 2) If you can program the ECU to use "drive by wire" to manage the idle speed, then you will also need the ECU to manage extra fuel at cold temps. 3) Don't use any idle control/cold start system, many have found the modern ECU works fine without it. But I'm guessing that may not apply to really cold climates like yours?

 

[rachaeljf]

If the system uses a drive by wire throttle, the throttle butterfly is operated by a stepper motor controlled by the ecu. The ecu can control the idle speed under all conditions, no need for any extra components.

 

[Dr.Jeff]

Rachael, I was thinking for cold starts the ECU will need to richen the mixture in addition to increasing the idle speed. So we may be discussing two different functions; idle speed control in general, and cold start conditions.

In other words, option two in my last post.

 

[rachaeljf]

Hi Jeff, yes, the ecu will richen the mixture for cold starts and warm up. I believe separate cold start injectors went out in the 80s. The LE2-Jetronic used on the Mk1 UT engine has no cold start injector, but the inlet manifold still has the boss cast on the end. It still used the old style AAV though. The Mk2 changed to a PWM controlled idle control valve.

I know MegaSquirters have come up with drive by wire controllers, but it is a risky area for DIYers because of the danger of the ecu or controller crashing and holding the throttle open. I would also be concerned for a sophisticated DBW-capable aftermarket ecu combined with DIY conversion to drive by wire throttle as who knows what a DIYer's wiring might be like. If the car is electrically noisy there could be problems unless the ecu is bullet-proof. I would expect such an aftermarket ecu to be programmable for a throttle potentiometer to allow DIYers to stick (no pun intended) with a cable/mechanical throttle.

 

[Bjorn Nilson]

Hi Bjorn, if your ecu uses a drive-by-wire throttle it will control the idle speed without the need for a separate idle control valve.

Maybe you misunderstood me. Sorry for my poor English. What I mean is that the throttle is driven by my right foot ONLY. Only the TPS is connected to the ECU. The ECU can handle cold starts by reading engine temp and add more fuel to injectors, adjust for higher idling speed... However I assume more air is needed as well, and that's the problem as the ECU or TPS cannot open the throttle. Same situation must also appear when engine is under load from alternator, AC etc. I do believe a valve is needed to handle this?

 

[Bjorn Nilson]

I found the same information when I was researching my aftermarket ECU setup. The modern aftermarket units like to have modern sensors with parameters that they understand. There are several choices of commonly used items available very inexpensively that work excellent. For example here in America the sensors from General Motors vehicles (e.g. very common Chevy's, etc). See what the ECU maker's information suggests.

3) Don't use any idle control/cold start system, many have found the modern ECU works fine without it. But I'm guessing that may not apply to really cold climates like yours?

SAAB and Volvo sensors are commonly available here, normally manufactured by Bosch. Bosch also have a "Motorsport Series" of sensors and triggers at reasonable cost and I am going for those. They are guaranteed to work with MaxxECU.
I drive my X on dry summer days only and that means 60-85 degrees F. Normally the engine heats up quickly so therefore I think it's worth a try without the valve. But it would nice to have a steady idle speed also during engine load from alternator etc. -I will have lots of fans to prevent overheating when standing still.
Some people think there are polar bears walking on the streets here in Sweden, but that is not true.

 

[gene cooley]

SAAB and Volvo sensors are commonly available here, normally manufactured by Bosch. Bosch also have a "Motorsport Series" of sensors and triggers at reasonable cost and I am going for those. They are guaranteed to work with MaxxECU.
I drive my X on dry summer days only and that means 60-85 degrees F. Normally the engine heats up quickly so therefore I think it's worth a try without the valve. But it would nice to have a steady idle speed also during engine load from alternator etc. -I will have lots of fans to prevent overheating when standing still.
Some people think there are polar bears walking on the streets here in Sweden, but that is not true.

You are correct that you can run it without the idle control valve, but ours (GM Ecotec using Megasquirt ECU) always works better with it working. It seems to have much better idle control that way.

 

[Dr.Jeff]

I do believe a valve is needed to handle this?

Yes, I believe you will need some source of additional air to work in conjunction with the richer mixture for everything to run smoothly and efficiently (but see my comment below*). That air source might be by way of a idle control valve (as Rachael's last post described) or possibly the throttle plate (butterfly) position. But as you say, just changing the throttle plate position will also change the TPS reading, which will change the ECU output, etc. So I don't know exactly what would be needed to make it work that way. Using a idle control valve like the Bosch ones on VW's and many other vehicles seems the easiest method.

However as it has been noted, it may not be completely necessary to have a warm-up / high idle circuit at all. But as Gene and Rachael both say it will be much smoother and run more efficient if you do. Especially if you need to bump up the idle speed intermittently for a AC compressor or huge alternator. *Some ECU's may be capable of doing that without a idle control valve by reading load, temp, and several other parameters and changing the settings electronically. Unfortunately I'm not familiar with how that is set up, the ECU I'm planning to run is a bit less sophisticated and as far as I know using a ICV is the only way it will accurately control it. Your MaxxECU may be different in this respect.

Regarding the sensors, I noticed some websites have lists of various sensor part numbers (like Bosch) and the specifications for them (electrical parameter ranges, etc). As I understand it, the ECU just needs to know what those parameters are in order to use them. So finding that information may be more important than what the actual sensor is or what it came off of.

And I believe there is a "Swedish Polar Bear". It looks like this:

 

[Bjorn Nilson]

You are correct that you can run it without the idle control valve, but ours (GM Ecotec using Megasquirt ECU) always works better with it working. It seems to have much better idle control that way.

A stepper motor seems to be a better option than a simple valve. MaxxECU supports the GM IAC (that I assume you are using with your Megasquirt). But how did you make it fit on a UT or X1/9 engine? Did you replace the whole throttle body or is it possible to replace the idle screw with the IAC? Or are there even "hose models" available?

 

[kmead]

There are a couple options: 1) Use the same ports that the AAV fit to and install a PWM idle control valve from another vehicle in its place (VW units are common), and program the ECU to richen the fuel when the idle control valve is opened (also by the ECU). ...SNIP... 3) Don't use any idle control/cold start system, many have found the modern ECU works fine without it.

I would agree.

Using the PWM ICV will be almost exactly the same as the existing AAV (once it is programmed) and will provide adjustable air flow independent of the throttle plate opening. The ECU will adjust fuel to match the added air from the PWM idle valve.

However many have found that it is not absolutely needed as the ECU can manage enriching the fuel to air ratio to give decent idle when cold, if somewhat imperfectly using the feedback from the O2 sensor etc. This is particularly true if you are not as concerned about general drive ability when cold (as in hop in, start and drive off) versus giving it 30 seconds or so to ‘warm up’

 

[gene cooley]

A stepper motor seems to be a better option than a simple valve. MaxxECU supports the GM IAC (that I assume you are using with your Megasquirt). But how did you make it fit on a UT or X1/9 engine? Did you replace the whole throttle body or is it possible to replace the idle screw with the IAC? Or are there even "hose models" available?
View attachment 29242 View attachment 29243

We are using a GM Ecotec in our 600 so GM parts are just bolt-on. The engine we are using had sequential port injection, drive by wire throttle, individual coils with feedback to the ECU, it also had a cam sensor for the injection timing. All of that is gone.
We batch fire the injectors, use a "waste spark" ignition with coils/plug wires. The throttle body is cable operated with the TPS and IAC (similar to what you pictured) built in to the TB.
If I was to do an X engine I would remove all of the original sensors/controls and start from nothing and replace them with GM parts including the cable throttle body. This is strictly personal preference, it's what I am familiar with, and it's a simple system. Parts are readily available new and used and they work with Megasquirt.
One other thing that we do is run ignition and fuel off the ECU only. We have an oxygen sensor, but because of the high compression the oxygen sensor won't live very long with the 110 octane leaded fuel. We use the oxygen sensor only to datalog runs. The one in the car now died about half way through the last autocross.

 

[Dr.Jeff]

But how did you make it fit on a UT or X1/9 engine?

Bjorn, the Bosch ICV is a hose connected unit that can be mounted in place of the stock Fiat AAV with the right hoses. It looks like this:

Red arrows are the "in" and "out" air hose connections that hook up to the same ports as the stock AAV did. The green arrow is the electrical connection to the ECU. There are basically two versions; a 2 wire and a 3 wire, depending on what your ECU prefers.

 

[Bjorn Nilson]

Yes, I've been looking at those and they differ from the valves from GM that are motor driven. I've read into the details and my ECU can handle both GM and this type (pulse triggered) with two or three connectors. However, I don't think the GM model will fit on the Fiat plenum so the Bosch style ICV is the only alternative. It will be cheaper as well, just 50-70 USD compared to 180 USD for the GM. The Bosch ICV was very common on Volvo 240/740/940/850 so it would even be easy to find on scrap yards for a bargain.
The MaxxECU can handle cold starts by enriching fuel, adjust timing etc, and with an ICV it will work even better.
I am excited to start working with the ECU, it has so much to offer and I am looking forward to learn more about it. If you are interested in functional details have a look at http://www.maxxecu.com/webhelp/index.htm
I believe this is one of, or even the best ECU on the market.

 

[Dr.Jeff]

There are various versions of the Bosch ICV with different hose diameters (nipple sizes). So if you have a selection of them to choose from, then look for one with the smallest hose fittings (the AAV fittings on the Fiat are quite small). Otherwise any of them will work. The 3-wire can be configured as a 2-wire easily. But you said your ECU can run either so that's not an issue (some ECU's cannot).

I have seen them sell new for as little as $20. But that will differ in other countries.

 

[lookforjoe]

Yes, I've been looking at those and they differ from the valves from GM that are motor driven. I've read into the details and my ECU can handle both GM and this type (pulse triggered) with two or three connectors. However, I don't think the GM model will fit on the Fiat plenum so the Bosch style ICV is the only alternative. It will be cheaper as well, just 50-70 USD compared to 180 USD for the GM. The Bosch ICV was very common on Volvo 240/740/940/850 so it would even be easy to find on scrap yards for a bargain.
The MaxxECU can handle cold starts by enriching fuel, adjust timing etc, and with an ICV it will work even better.
I am excited to start working with the ECU, it has so much to offer and I am looking forward to learn more about it. If you are interested in functional details have a look at http://www.maxxecu.com/webhelp/index.htm
I believe this is one of, or even the best ECU on the market.

Should be able to mount the IACV in a fashion somewhat akin to my LH2.4 setup:

All Volvo parts. The hose is Volvo EPDM (945751) sold by the meter, or parts thereof