Engine and Transmission Tech

MS1 is Wasted spark, not sequential.

As I said in my email to you yes MS3 is very very nice, but OTT for any Rover V8, some here use MS2 on TVRs etc for track days, but I have a customer with a MS1 power tweaked TVR and he outperforms so many "High Spec" Others - mainly due to it being set up spot on via Megaalogviwer / tuner studio AND a healthy time with a Rolling road to get spark map spot on. MS1 is easier to work with if complexity is not an attraction for you.

The Bosch 2 wire Air Valve I use is a PWM unit, hence "Tunable"

You can put stockings, high heels and lipstick on a Pig - but its still a pig

If others think MS3 is the answer to a Rover V8 then fine for them, the final result is only as good as the set up and tuning, I have even helped with a V12 1959s Meteor Tank - now on MS1 !

I have also (as I had to for my current own project, had to make VR sensor brackets and Trigger wheels for the 4.0 unit (as my 5.2 has this as a front end on it :O( I don't like th factory units as they are in the bellhousing, and do fail - particularly with what I do with them :LOL:






The VR Bracket has slots to allow adjustment to the timing, and also to get the correct Air Gap,
I think this proved to be a solidworks and Prototype nightmare to get spot on :O)

Hope this is of interest

Nige



Edited 1 time(s). Last edit at 04/28/2012 08:51AM by NigelB.

Thanks again, Nigel. This is all good info.

Cheers,
NCtim

Very nice sensor mount. There is a large market for those and the matching trigger wheel, especially if it will fit all of the Rovers, 215's, 300's, 340's, 350's and Buick V6's. In which case it may also work on the big block Buicks. (Can it be used with the stock mechanical fuel pump in place?) I think your development efforts could pay off nicely. The nicest design I've built so far bolts to the fuel pump boss and won't work if a mechanical pump is needed.

I'm with Bill on this one, the ability to independently tailor fuel and spark to each cylinder and set up auto-tune to let the controller optimize each one as opposed to batch fire of both fuel and spark with a one-size fits all approach has big potential payoffs. You let the MS3 vehicle spend the same time on the dyno as that MS1 and I think you'll see the difference.

But it isn't all about the Hp figures, driveability, or even economy and there can be no doubt that added complexity can take you into the realm of diminishing returns. For some, such as Bill and myself, the individual cylinder tuning is needed. Both of us run superchargers on one-of-a-kind custom intake manifolds. Without the uber budget to endlessly develop and test it is highly unlikely that you can get perfectly even intake distribution with such a design on the first prototype no matter how good you are. So while the MS1 will work, it may be very far from optimal. This is not an issue that the average builder has to deal with, but even so, the unequal length headers we are stuck with means uneven cylinder conditions, and any uneven cylinder condition is fertile ground for individual tuning.

In regards to your IAC solution, that sounds quite creative but the issue I ran into with MS1 was an inability to both control idle air and provide a timing advance output (SAW signal) for the EDIS. Even with the 2 wire Ford PWM IAC I wasn't able to run both. The best I was ever able to do was to use a solenoid for fast idle and even then (going from memory here) I think it was an either/or situation where I could have EDIS advance OR fast idle but not both. I do remember feeling very frustrated with this limitation which I considered short sighted, and it led in short order to an upgrade to the first MS-II beta daughterboard, and then the newer (current) MS-II configuration. (anybody want to buy a beta1 MS-II?) If you have solved this dilemma I applaud your accomplishment, and wish I'd known about it 8 or 9 years ago. Even now I would like to know more of the details.

So all I'm saying is that it's a real good idea to make sure you have a clear upgrade path, and if you might need the higher features it is cheaper in the long run to provide for it at the beginning rather than later. The v3.57 MS board is a good piece. The MS-II or MS-III cards plug right in for ease of upgrade and there is an MSX expander for more inputs and outputs (need the bigger enclosure), plus the GPIO which uses a separate enclosure and can serve many functions including transmission controller. Most of us go more complex because of a need. I don't know very many people who want to go more complex simply for the sake of complexity. OTOH, I DO know people who will go high tech for bragging rights, and that is a legitimate excuse.

Jim



Edited 1 time(s). Last edit at 04/28/2012 11:35AM by BlownMGB-V8.

I agree, The MS3 is a great solution for what you are doing, as you are pushing the options of what you can do waaay
over standard. The problem is that for some MS is just a "Small Part" of their hobby, and more than often they haven't got a ****ing clue when it comes to ECUs tuning, making a wiring loom, etc etc. I have had emails saying ....

"Like the sound of your MS1 system - can you do me one with the correct plug for my Lucas harness"

"Will this run my x y z enghine without major modifications"

"Can you build me a wiring loom and get it switched completely to Megasquirt if I bring it over 1 afternnon and wait ?"

So, faced with this, a MS3 would baffle them. Actually on rethinking what I have typed the MS1 would baffle them. In fact its possible if you shuffled their left and right shoes around it woulod puzzle them, thankfully I don't get that many of the "I am a Muppet" Clan, though some do make me blink at the monitor ....

Most peps I deal with have some knowledge of most things, but are only "Good" at a few. Some can Tig weld "Unobtainium" with ease, but not build a ECU to save their lives, some can wire but not weld, some can't weld wire or do much else, but, with detailed instructions and some support want to have a go, I try to cover all.

I did have a "Proper Job" after I found out that this well paid "Proper Job" was likely to end up with me in a box underground quite shortly I was luckily "Let Go" and wondered what to do, I had friends literlaly begging me to megasquirt their trucks, and after a while I thought "What if I could make a complete kit that even some of the muppets could actually follow with ease and megasquirt their V8s ?"

I love my V8s, I do get involved with other engines (aparrently there are oter engines out there than V8s) and I love what I do

I tinker, make up brackets and solutions to problems, I am amazingly getting known in the UK as a guy to buy stuff from becuase I will help when stuck, the winner than near beat me was the "Chap" who said he couldn't get his engine to run. after WEEKS of calls I ended up at his 4x4 racer and tried to find the fault. As an autoelectrician by trade the install was perfect, a beautifull job.....

After 6 hours I was stumped, NOTHING and I mean NOTHING mad it run, I checked everything - several times - you know the I have looked in here once but I will just lok again in desperation that the f up fairy may have visited and swapped it sinmce I looked last time sort of look at ....

I sat in the corner on a tarpalin and drank a coffee, I was uncomforatble, lifted up the tarp to see what I was sitting on, its was a 300 TDi LR engine - Whats this for I asked ?

"That mate was the old F engine which I F wished I havd never F removed for the F Poxy F V8 and your bl**dy megasquirt........"



















And tell me, what exactly is the fuel in the Tank"

:O)

Prob sorted

MS3, please ........................ :O)

With my Kits of MS1 the majority of customers are "LR Challenge" Motors, V8s and water don't mix, as I am sure many here will know.......heres why I love MS ....

[www.youtube.com]

Then the TVR Boys found me, there old Lucarse ECU are dying, some want MS2, many go MS1, easy to help

MS3 ius superb, no Q, its just the "Main Market" I operate in has peeps with little / no / none skill :O) and all plead proverty
and many just wnat a simple relaible foolproof system that they can sort out and get to grips with

Supplying them with MS3 would see the remainder of what hair I have fall out and the Will to Live prob slip away from me ....

Hence my Love of MS1

MS2 I think is more / was / a stop gap for MS3. Ms3 is a world apart from MS1, and I still think there is a market for all.

ALL MSs are a vast jump in terms of qulaity relaiblity and user freiendlyness vs Lucarse prince of Darkness stuff, if ever you wnat a shock, unwrap a Lucas V8 Harness and "Admire" and gasp at the "Quality" especioally around the joins ......

Not sure what the prob was with PWM etc but I have no probs with it working with everything else...Odd

But then again so am I :O) ...........

Nige



Edited 1 time(s). Last edit at 04/28/2012 02:09PM by NigelB.

Case in point, Mopar Gen 3 hemi, you can use Mega 3 to run everything, try to limp along, bound and gaged with the factory set-up or spend thou$ands, with some aftermarket sharks. A few folks cave in to anti-tech sentiment and spring big buck$ for carb and distributor adaptions. This would be a thoughrougly well engineered engine, fed and controlled, from the dark ages. IMHO, why bother with a modern design at all ? Cheers, roverman.

I am glad I started this post. I didn't realized there was such an interest in FI and MS. There will be much more questions asked in the future about this .
Thanks Nigel for the info. Where exactly is Costa del South in the UK ?
I'll be coming to the UK next year for 6 weeks so I might make some time to visit if work schedule allows.
I'll be working at Sizewell. Got in touch with RPI but had complaints about the way they treat customers.( Never got the VAT back for parts imported in the USA).
I am going to stick with MS1 for a while.
Werner

RPI ....Oh yes I tried dealing with them a couple of times

Spoke to one of the guys - Chris - a Legend in his own mind, Like Adolph Hitler - but without the charm
I couldn't believe the attitude and unhelpfulness sprouted down the phone at me.

Dealt with John Eales (JED) instead - and gave him my money for top servic and support :O)

Nige

Quote:

I actually prefer the Ford IAC which is PWM controlled and needs only 2 wires. I like the configuration and mounting better too.

Jim, I'm curious to know which Ford throttle body / IAC you're thinking of?

I've looked hard at some of the Mustang throttle bodies - there must be a dozen companies making aftermarket versions and some of them are appealing - but I'm leaning toward a Chevy 4.3L V6 (72mm) throttle body because I think its form factor might work a lot better for my installation. It's only 56mm thick (flange to flange). Chevy mounted it as a downdraft, but I'd mount it vertically with the throttle linkage on driver side. (I prefer a linkage to a cable, and its design appears to suit that better than most.) Its IAC is tucked-in pretty neatly to the body, side by side and about the same size as the TPS, both on passenger side.

Anyone have a comment about using the GM 4-wire IAC with MS2 or MS3?

Here's what I don't understand about the Chevy throttle body: they put a "diffuser" on the back of the throttle plate that blocks a lot of airflow, particularly at low throttle openings. Even at wide open throttle the diffuser probably blocks 25% of airflow! Aftermarket throttle plates are available without diffusers... although removing the diffuser is as easy as grinding off two rivet heads. The diffuser is in addition to a "nautilus" shaped cable connection - so why did they do both?


(by the way... the diffuser is shown here in a video about how to remove it: [www.youtube.com] )



Edited 1 time(s). Last edit at 06/03/2012 01:25AM by Moderator.

Curtis

The GM 4 wire IAC works well with MS2/3. For the most difficult part for me was tuning the IAC for my application. Since there is no position sensor in most IAC motors, they are controlled by steps or voltage applied for a certain amount of time. (step size). Since some IAC motors can react more quickly then others, its up to the tuner to set the step size and other values based on how the idle speed responds during warm up.
Normally the default settings in MS are pretty close, then it just requires some tweaking.

In MS2 your options are warm up only. In this case you set the idle speed with the throttle stop screw and the IAC is used as a fast idle device for cold starts/warm up. Once the engine is warmed up the IAC pintle is fully extended or closed.
With MS3 you can have either "warm up" or "closed loop" idle control. With closed loop idle control, the throttle stop screw is adjusted to a "minimum" idle speed which is slower then what your "target idle" speed would be. Then MS3 extends or retracts the IAC pintle based on desired idle rpm/engine load.
Most all newer vehicles are closed loop idle controlled.

Link to MS3 idle control page [www.msextra.com]

Currently I'm still running my IAC set up as warm up only, with the same settings as I had while the car was using MS2. I haven't tried using the closed loop IAC feature in MS3 yet. Its one of those back burner projects that I may play around with in the future when I have the time. I would think that the GM 4 wire IAC should work for closed loop as well, since GM does it!

The diffuser is there to direct air flow in relation to how the EGR gases are distributed within the stock GM Vortec intake plenum. It also allows GM to make one throttle body for the different engine displacements. The 4.3L has a larger diffuser then the 5.7L.
I have seen the diffusers fall off before. We had a truck in a couple of weeks ago that the diffuser came loose and was getting caught in an intake valve, the motor didn't like that so much!
I removed the diffuser on mine by drilling out the rivits and installing solid rivits (instead of pop rivits) in the holes. I'm not a big fan of cutting the diffuser, since there is still a chance that the left over piece could still come loose.

Bill



Edited 1 time(s). Last edit at 06/04/2012 10:47PM by MG four six eight.

This is a great topic!!! Thanks for posting Werner.

I have the 14CUX system and I can't seem to get the car to run well at low RPM (engine misses between 1000-2000 rpm) or get the (new NGK) oxygen sensors to go into closed loop (the two are probably related. Wiring checked out okay). It might be because I am running a fairly agressive cam and have it set at 104 degrees. So I am curious to know if the MS might be the solution to my EFI woes...

Very helpful comments, Bill. Thank you!

I think I might leave the throttle plate's diffuser in place through initial development, on the theory that a 4.3L (72mm) throttle body is probably larger than ideal for my 3.5L engine anyhow. Last night I mocked-up a plenum design, and today I visited my local machine shop and got them started on machining a custom plenum base. The proposed plenum top is extremely simple in form... still not sure if it will be carbon fiber, aluminum, or satin black powder-coated mild steel. As designed, the whole plenum will be so narrow that Rover's steel fuel rail will be removable without disturbing the plenum top or throttle body. I might end up fitting an extrusion-based fuel rail, but my initial plan is to simply rework the two ends of the one-piece tubular rail.

So here's my next question:

For MS2/MS3, how helpful is it to fit an adjustable fuel pressure regulator? Is an OEM style regulator more robust? Is there much real utility to having a gauge, or will I only need one for initial development? (Aesthetically, I'd prefer to keep things simple and monochromatic...)

The main disadvantage of the Rover fuel rail is that due to the injector angle it is a pain to install. This can be fixed by replacing the big bend with a braided hose though. If you are using the Rover lower Intake, keeping the trumpets is probably a good idea sin e they tune the runners.

If someone comes up with a particularly good fpr I would like to know the details. I've been using Ford but they are not that easy to add to a custom rail. I tried an adjustable but went back to stock for simplicity and ease of replacement. I feel it is better to use a standard rail pressure and match injector size and pulse width to the engine. Fpr's generally are a band aid for systems that aren't adjustable.

A gage is handy for tuning or troubleshooting but otherwise is a potential leak. Rail pressure rarely changes once the system is stable.

A midrange surge is an extremely common problem in modified OEM systems. Frequently it cannot be cured using the stock controller, even if there is axway to tune it, and it doesn't seem like anyone wants to discuss it. I got rid of it on my car only when I ditched the Ford controller, which with a tweecer add on was very tunable if you only had access to Ford's secret files. With MS-II it worked just fine.

Jim

I would agree with Jim on this. Generally its best to use a stock pressure regulator if the horsepower levels are close to stock levels and the stock injectors are being used. ECMs have a useful range of pulse width control. If the injector is to large then the pulse width becomes to narrow and the engine becomes difficult to tune at idle and low rpm cruise. If the injector is to small the pulse width can be maxed out at WOT and cause a lean condition.

Adjustable fuel pressure regulators can be handy if the engine is highly tuned/modified and there is not a suitable sized injector avilable for the horsepower levels.
An adjustable fuel pressure regulator allows the tuner to move the "pulse width window" up or down slightly by changing the fuel pressure. Often times simply changing the pressure by 5-10 psi will be enough to bring the pulse widths into the ideal range for the ECU. Once the ideal pressure is found, normally it is left alone since changing the fuel pressure will change your entire tuning requirements.

There are calculators on the MegaSquirt web site and these will get you close for injector sizing. However you won't know where your pulse widths are until the engine is up and running/tuned. If the engine's horsepower was over/under estimated, or the horsepower level has been increased/detuned, then an adjustable regulator may be an option instead of buying 8 new injectors. (been there done that)!
The main thing is you want to stay in the fuel pump's ideal working range which is usually 30 to 60psi for most pumps. If the pressure has to be adjusted out of this range in order to bring the pulse widths in line, then the best option is to change to a different flow rate injector.

An advantage MS3 has over MS2 is the finer fuel table resolution .1% compared to 1%, this can be helpful when tuning for very short pulse widths. With the finer resolution I've noticed that the MS3 is a little easier to tune at idle and low load (city driving) conditions. For a car driven on the race track, it won't make a huge difference. For a street car, driven in the city that has larger injectors and other mods MS3 and an adjustable regulator are probably worth while investments.

Bill

I copied the following from the MS manual that explains the effect of pulse width at low load/idle.

[Quote]

Idle Pulse Width

You have to select your injectors based on the maximum horsepower your engine can produce to prevent the engine from running lean at wide open throttle. But why not just pick the biggest ones you can find?

The answer has to do with idle and cruise pulse widths. If you use very large injectors, your idle pulse widths get very short. This can drastically reduce the mixture ratio control that you have during idle and cruise situations, and lead to very poor driveability and seemingly strange tuning behaviour.

To illustrate, suppose you have established that your engine produces the lowest MAP reading at an idle pulse widths of 1.2 milliseconds, and your opening time is 1.0 milliseconds (considered the 'standard opening time'). Recall that MegaSquirt can only change fuel by 0.1 milliseconds at a time.

And also recall that MegaSquirt assumes NO fuel is injected during opening (which is close to true, since the injectors remain closed until the coils charge, then they snap open at the end of the opening time). Now if the net effect of the enrichments change by 2%, the pulse widths don't change at all. Even if they change by 49%, nothing changes. But once they change by 50%, the pulse widths suddenly changes to 1.3 seconds.

So the next leaner possibility is 1.1 seconds, and the next richer is 1.3 seconds. However 1.3 milliseconds is not 1.3/1.2x100% = 8.3% richer, instead it is (1.3-1.0)/(1.2-1.0) = 50% richer! The mixture becomes very, very rich, and the engine runs poorly.

To confuse your tuning efforts further, it may be that you are already near a threshold, so that a small change in one parameter makes a very big change in the air/fuel ratio in one direction, but no difference at all in the other direction!

But doesn't the EGO correct? Actually, it can't. Even if you set the step size to 1%, nothing happens until the 50% (i.e. 1.3 milliseconds) threshold is reached. That is, the step size only takes effect once the 0.1 threshold of PW is reached. And if the number of ignition events between steps is large, the engine may stumble and die before it recovers and leans out. So in fact you may be better to set the O2 step high (50%), and the number of ignition events low (say 2) so that the average over just a few injections is correct. It is a band-aid approach, however, and likely to induce ignition related problems.

Obviously the converse is true if the engine goes lean. It has to go at least (1.1-1.0/(1.2-1.0)=50% lean before anything happens. If does go lean, it may back fire and die before it gets a chance to become richer.

You might think you can get around this by decreasing the injector opening time (to get a larger "adjustable time") and increasing the VE (or req_fuel), but that doesn't work because the 'ideal' injection time is still 1.2 seconds, and the permissible step is still 0.1msec, regardless of the way you add the components of the pulse width up.

And making matters worse is the fact that many high-performance engines will want even lower pulse widths at cruise than at idle, compounding the tuning problems and introducing more driveability issues. A system with a very short pulse widths like this will be difficult to tune. It will appear not to respond at all to enrichments over a certain range of a parameter (say IAT), then suddenly it will seem to change so drastically that you seem to require an entire new set tuning values.

Now even if your engines idles perfectly at a very low pulse widths, changing load, speed, and other variable (EGO, IAT, etc.) will demand slightly different air/fuel ratios. However, none of them are likely to need exactly the +50% you have to choose from!

This is why several aftermarket ECU manufacturers recommend an idle pulse widths of not lower than 1.7 milliseconds. If yours is lower than this, you need to address it before you will be able to tune your engine for all operating conditions. Ultimately the best solutions are appropriately sized injectors or staged injectors.[quote]



Edited 5 time(s). Last edit at 06/06/2012 10:13PM by MG four six eight.

Very good reference Bill. I see someone has been working on the manual. Could you post a link please?

Jim

You guys are so incredibly helpful. Thank you!

Since I have two Rover fuel pressure regulators, I guess I'll try to make that style work. I like the price!

---

Now I've turned attention is on what should probably be even simpler... the intake air temperature sensor (IAT).

Q1: for a normally aspirated engine, is there any reason to prefer mounting the IAT either before or after the throttle body? (My intuition is that upstream of the throttle body is cleaner, especially if PCV is ported in nearby. Downstream may be warmer.)

Q2: should I try to arrange it so the airstream flows over the IAT sensor, or is it fine if the sensor is just in near proximity?

Q3: do you expect there's any significant performance to be gained by putting a phenolic spacer between the lower manifold and the plenum in an effort to reduce intake air temperature? (Some of the UK performance shops sell spacers for this purpose. I could make my own if it truly makes sense, but I'm skeptical.)

Jim

Sure! Link to main menu for MegaSquirt manuals [www.msextra.com]

When searching through the manuals/links, I've found that most of the basic information such as injector sizing, fuel, ignition tuning, etc can be found in the MS1 manuals.
Then for more specific features or advanced topics, the information can be found in the MS2 and MS3 sections.

Curtis

I've found that locating the IAT sensor as far away from the throttle plate as possible works best. The issue is with heat soaking the sensor on re-starts.
For example I had the IAT located fairly close to the throttle body and when I would shut the engine off for 20 minutes or so. Then do a re-start the engine would run lean for a short time until the sensor cooled down to ambient temperature. When I would check the data the IAT could be reading 115*F when the ambient temp was only 70*F.
In theory the in rushing air should cool the sensor down right away. If I started the car and headed out on the highway right away, the sensor would indeed cool to ambient quickly. However if I started the car and was just doing stop and go driving, the sensor would take much longer to equalize to ambient temperature. At the lower RPMs/throttle openings there isn't as much air flow across the sensor to cool it.

I ended up moving the sensor to the air inlet at the cowl. In this location the sensor dosn't get as hot during a hot soak condition and the sensor responds to ambient temps much more quickly.
There are correction tables in MS3 to help compensate for heat soaked sensor as well. I've played around with the settings some and they can make a difference. Ultimately I found experimenting with different IAT locations gave me the best results though. Depending on your air intake set-up, usually its pretty easy to move around the IAT sensor!

It is best to have the sensor directly in the air stream.

Not sure how effective the spacers are. I would think that they could help somewhat, as a lot of the OEMs are now going to plastic intake manifolds in order to reduce air intake temps.
Bill



Edited 3 time(s). Last edit at 06/07/2012 11:16PM by MG four six eight.

Interesting. Sort of makes me wonder if a location in front of the radiator and not in the intake at all might not work well.

Jim

For those who draw they're air intake forward of the radiator and behind the grill, I would think that it work quite well.
The main thing is to locate the IAT sensor in a position where it can measure true incoming air temps. So for installations that have no cold air intake set-up, that most likely would mean locating it the air stream near the air filter.

There are also MAT (IAT) correction tables in MS2 and MS3. So for example once the engine is tuned you find that the engine runs slightly rich in the morning and maybe a little leaner mid-day when the ambient temp is hotter. You can use the correction table to automactically adjust the VE table up or down as the ambient temperature changes.

MS3 takes this one step further by offering both the correction table and an additional setting (MAT correction value) that allows you to change the percentage to which the physics of gas law is followed.

The method I use to tell if I need to use correction table is to first get the VE table, ignition timing table, etc tuned so that the engine runs well. Then drive car on a cold morning with auto-tune on and in the "hard or very hard" setting. Then check to see if auto-tune wants to change most of the bins richer or leaner. (It's easy to tell because the numbers will be either blue or red) Then leave the VE as is (don't allow Auto tune to change the VE table). Next drive the car with auto-tune on during a hot temperature day. If auto-tune wants to correct the VE in the opposite direction as the cold morning drive, then I'll use the MAT correction table.
Normally its best to do this test several times, to account for changing weather conditions etc. Also its best to start out with a small amount of correction and work your way to higher correction values if needed.
The goal is to get to the point where auto-tune wants to change as few VE bins as possible whether the ambient temp is hot or cold.
[www.msextra.com]

Bill

Very good tip Bill. That is something I haven't tried yet, but I will now that you have explained it.

I will consider mounting the IAT just behind the grille. That will eliminate more wires up to the Enderlie style scoop/TB. Both should be at the same temperature as both are at the leading edge of the car in terms of airflow.

Jim