Mega Squirt Project Details

Thanks Dom. I've referred to it many times. I only wish all of the images in the original posts were still accessible. But this is the next best thing.
 
This is an aside to share a set of parts which would allow more modern injectors to be used with our standard intake manifold and existing fuel rail approach on an X. This would allow using Microsquirt to drive modern injectors with our existing parts thus minimizing the difficult of changing to a modern programmable system.

For most modern stand alone injection systems they use injectors which are high impedance versus the low impedance used in the Bosch L Jetronic system Fiat adopted in 1980.

Later Bosch changed the L system to use the other injector style (found on BMW, Volvo and others) which still had a flexible hose supply, barbs etc. Of course the choices are limited in terms of fuel flow and so on as well as they are just plain old.

There is an adapter available which allows a flex hose supply with later mount type injectors:
https://www.efihardware.com/products/2358/14mm-Injector-Oring-To-Hose-Tail-Adapter-Steel

This doesn’t solve for mounting the injector into our manifolds (I haven’t done any research into that) but its at least one part of the solution.

Cross posting this in a few relevant threads to leave a crumb for others to follow in the future...
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Has anyone installed a knock sensor in the MegaSquirt builds? I notice the Uno Turbo has one, I wonder if this could be used for a NA FI 1500 MegaSquirt build? Any recommendations on other knock sensors that would work on this block/head?
 
davejake said:
Has anyone installed a knock sensor in the MegaSquirt builds? I notice the Uno Turbo has one, I wonder if this could be used for a NA FI 1500 MegaSquirt build? Any recommendations on other knock sensors that would work on this block/head?
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Knock sensors were discussed at length somewhere in the "turbos for the X" thread. There is a knock sensor option available for MegaSquirt (MS). Depending on the model of MS ECU it may require a adapter module. However as I understand it the results haven't been extremely successful.

While the basic knock sensing technology that is commonly used isn't very sophisticated, it is highly dependant on several factors for each specific application. So getting it right on our odd engines may not be likely. However even more to the point, all of the top engine experts that I discussed it with said they don't use one on their builds. Knock sensors are exactly that - they sense knock after it has happened. Instead they tune the ECU correctly to prevent knock in the first place. Furthermore the one that Fiat used on the UT is ancient technology so I wouldn't rely on it for any modern build. This whole subject has always been debated. Initially I planned to use one for my turbo build (where knock is critical). But the more I researched it I've changed my mind.

In recent years there's a new knock sensing technology being developed. It is much more sophisticated and precise. To the point it can detect knock early enough to actually prevent it. However that type of system is intended for development as a new engine is being designed, to be part of the engine's actual architecture (the sensor is part of the combustion chamber). It is still being refined but a couple of companies are selling preliminary versions of it that supposedly can be used on any engine (although it hasn't been proven yet). But they are extremely expensive....certainly not something for our antiquated little engines.
 
The original UT knock sensor can not be used with modern aftermarket ECU's. Bosch Motorsport knock sensor works well and is a direct fit on Uno Turbo ( I am almost sure it fits the 1500 as well). However, the ECU must "learn" the knocking sound wich is unique for every engine. This is s complex and time consuming operation on the Dyno.
As Dr. Jeff says, on a correctly mapped engine (with a modern ECU) the need for a knock sensor is limited.
 
Following on, the need for a knock sensor is dependent on how aggressive one is chasing the tune and the associated ignition timing. A knock sensing system pulls the ignition timing back when it senses knock/preignition. If one isn’t as aggressive with ignition timing it is unlikely you will need to retard timing.

Turbo engines are however the exception as intake air temperature, boost and ignition timing can all conspire to cause preignition. The engine management system should be looking at those all as inputs and reacting appropriately ahead of time to inject more fuel, alcohol or retard timing. Should… Lots going on there.
 
Thanks for the comments on the knock sensor. I agree, we shouldn’t need it, just got excited when I saw one on the UT and thought about adding it to my current 1500 FI NA build with megasquirt ecu.
 
Does anyone know how this adoption translated into performance when it was finished? I would imagine fuel economy increase due to better control but did it increase power?
 
davejake said:
Thanks for the comments on the knock sensor. I agree, we shouldn’t need it, just got excited when I saw one on the UT and thought about adding it to my current 1500 FI NA build with megasquirt ecu.
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Is the knock sensor normally supported on all MS units? I am running MaxxECU and I bought the "Race" version just to benefit from the built in support for knock sensor. That cost me extra $$ but it was cheaper than buying the "Sport" edition and the extra module for additional sensors.

I am also building a 1500 for my 128 SL and the dual Weber 40 will be replaced by FI. My experience in MaxxECU Race is very good but on this car I will use their most simple and cheapest unit with no support for knock sensor and Bluetooth/Android virtual gauges.
With the angry EU cam, 4to1 manifold and porting I expect 110hp from it?
 
Bjorn Nilson said:
Is the knock sensor normally supported on all MS units?
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No. The better ones (read "expensive") do but others do not. And like Bjorn decided, it is difficult to justify such a high end (and expensive) ECU for many routine car builds. There's add-on modules available from third party companies to integrate a knock sensor into the MegaSquirts that don't support it. But my understanding is it's a simple amplifier for the common frequency that many sensors read, and converts that to a generic input signal, which can then be programmed (in the ECU) to retard timing. And as you might guess, the feedback about it isn't very impressive. Frankly I don't see how it could possibly work at all.

Many decades ago VW had a similar device when they first went to FI (a mechanical system in those days). It was commonly referred to as the "knock box". It was a add-on module to the distributor harness. A Bosch sensor was mounted on the engine and when knock was read the box retarded timing. However it tended to read a lot of false positives (mistake noise for knock). So you ended up with severely retarded ignition timing a lot of the time. As Karl said, you need to read a lot more than noise (i.e. the block sensor). And that's the problem with some aftermarket ("standalone") ECU's that include a knock sensing function; they don't do it right, and therefore aren't very effective. To my knowledge there's only a couple of standalone ECU's on the market that have a effective knock function [At least as of a couple years ago. With many trade shows cancelled due to COVID it's been difficult to keep current with things in recent years].
 
KBabcock said:
Does anyone know how this adoption translated into performance when it was finished? I would imagine fuel economy increase due to better control but did it increase power?
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Are you referring to swapping to a MegaSquirt ECU for the X's FI system? If so then I recall there have been some members that posted dyno results with it. Basically it improves efficiency. And that translates to a lot of improvements; performance, fuel economy, emissions, drivability, smoothness, starting and warm-up, etc. But it's completely dependant on the effectiveness of the tune (mapping of the ECU)....a poorly programmed one can be worse than the stock system.
 
kmead said:
Turbo engines are however the exception as intake air temperature, boost and ignition timing can all conspire to cause preignition. The engine management system should be looking at those all as inputs and reacting appropriately ahead of time to inject more fuel, alcohol or retard timing. Should… Lots going on there.
Click to expand...
Definitely. And it was my turbo build that got me learning more about knock control. The problem I found was to get a good knock control system you need to spend quite a lot on one of the better ECU's. I'm talking about thousands for just the ECU; that's about the total value of my entire X! Verses the MicroSquirt for $300. To me a X build simply doesn't warrant that level of equipment. But I realize that's a personal decision. However there are other ways to deal with knock on a turbo engine. Use a very effective intercooler, tune it right, add a oil cooler, upgrade the cooling system, improve oil circulation (e.g. squirters), keep the compression ratio reasonable, cold air supply to the intake, use proper building techniques, etc. In other words, build the engine so it won't knock in the first place.
 
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