Gti6 Management On An Mi16

[Miles 331 1 Cars]

Aftermarket ECU;s are pretty reliable, I;'ve yet to have a problem with one after a good 10 years of using them, But as you;ve said thou the old Motronic is very good and re-liable, but now with everything wearing out it is getting worse now.

 

I agree with Megasquirt, It's not something I would install on anything nor any mappers I know would either, DIY is the problem here and you can run into allot odf issue's.

So you can;t compare that with a mainsteam ECU

[Cameron 16]

Not at all, a partially closed throttle is very uneconomical due to pumping losses, what you have described is the opposite of an economical petrol powered car.

 

Unfortunately, since this is a petrol engine, the throttle has to stay.

You could put a very small throttle body on instead and have the same result - limiting the amount of air that can get into the engine. And since the air / fuel ratio has to be at a certain level for combustion to happen, you're also limiting fuel consumption. Also fuel efficiency decreases with engine speed, so a low rev limit will also help reduce fuel consumption.

Edited December 17, 2009 by Cameron

[Veero 1]

Sorry to be slightly off topic, there seems to be a fair amount of negativity towards Megasquirt here. Any reason why them in particular?

 

Also this thread is a little disheartening, basically I would like a reliable running engine as it seems impossible to acheive with the particular standard bits I have, but the general concensus is that TBs + aftermarket management is exclusively for rich people. Great.

[Miles 331 1 Cars]

Megasquit as I call it, is that the main problem is the DIY issue which can cause allot of headache's for the installer/mapper and the only back up I guess is you and not someone who has had years of experance with say motec/Omex/Emerald etc to name a few.

A Emerald ECU and Loom is cheap so it's hardly worth the hassle in my mind.

[jackherer 543]

Unfortunately, since this is a petrol engine, the throttle has to stay.

You could put a very small throttle body on instead and have the same result - limiting the amount of air that can get into the engine. And since the air / fuel ratio has to be at a certain level for combustion to happen, you're also limiting fuel consumption. Also fuel efficiency decreases with engine speed, so a low rev limit will also help reduce fuel consumption.

 

A small throttle is just as bad as a partially closed one, economical driving involves a perhaps surprising amount of throttle opening and RPMs. I'm not going to go massively off topic here, just read wikipedia:

 

http://en.wikipedia.org/wiki/Engine_efficiency

 

At slow speed (i.e. low power output) the efficiency is much lower than average, due to a larger percentage of the available heat being absorbed by the metal parts of the engine, instead of being used to perform useful work. Gasoline engines also suffer efficiency losses at low speeds from the high turbulence and head loss when the incoming air must fight its way around the nearly-closed throttle; diesel engines do not suffer this loss because the incoming air is not throttled. Engine efficiency improves considerably at open road speeds; it peaks in most applications at around 75% of rated engine power, which is also the range of greatest engine torque (e.g. in the 2007 Ford Focus, maximum torque of 133 foot-pounds is obtained at 4,500 RPM, and maximum engine power of 136 brake horsepower (101 kW) is obtained at 6,000 RPM).

[Cameron 16]

Funny, 'cos that goes against almost everything I was taught in my first year of uni, and also against my Mondeo owner's manual.

I think that you, or the bloke who wrote that article, or both, have got a little confused here. What that article means is that the relative efficiency has decreased, i.e. the slower you are going, the less "efficient" your engine is as you are using a smaller percentage of the power to propel you forwards; this seems to be confirmed when the article mentions zero efficiency at idle. In reality, the slower the engine is rotating, the more completely the fuel burns and the more the engine makes the most of the available cylinder pressure. Hence why truck engines operate at 1000-1500rpm, and why ship engines operate at very low rpm.

 

If you want to confirm this, apply a set amount of throttle and watch your mpg reading go down as the revs go up.

[Galifrey 1]

Funny, 'cos that goes against almost everything I was taught in my first year of uni, and also against my Mondeo owner's manual.

I think that you, or the bloke who wrote that article, or both, have got a little confused here. What that article means is that the relative efficiency has decreased, i.e. the slower you are going, the less "efficient" your engine is as you are using a smaller percentage of the power to propel you forwards; this seems to be confirmed when the article mentions zero efficiency at idle. In reality, the slower the engine is rotating, the more completely the fuel burns and the more the engine makes the most of the available cylinder pressure. Hence why truck engines operate at 1000-1500rpm, and why ship engines operate at very low rpm.

 

If you want to confirm this, apply a set amount of throttle and watch your mpg reading go down as the revs go up.

 

The thing is, you cannot drive a car at 4500 rpm economically, it is the engines most efficient, but we use lower rpm where the engine is less efficient due to the gearing. Manufacturers have experimented with running a multi cylinder engine at high rpm and efficiency with only 2 cylinders firing, engaging more cylinders as the engine needs more power.

 

Ships are a different kettle of fish, they are long stroke designed to be efficient at lower RPM, Diesels are similar....

 

At present tho, the only way to drive economically in a car, is high gear, low rpm, small throttle opening if you drive in 2nd at 4.5k rpm 75% throttle, you will burn a lot of fuel, despite the engine running efficiently. Once you get to high road speeds, mass of the car, wind resistance add additional load, so even tho the engine is efficient, other factors drive down the mpg.

[Cameron 16]

Manufacturers have experimented with running a multi cylinder engine at high rpm and efficiency with only 2 cylinders firing, engaging more cylinders as the engine needs more power.

 

It's a clever idea, but I reckon you would have to make use of a fully electronic valvetrain to take advantage of it fully. Otherwise you'd be experiencing 100% pumping and frictional losses from two cylinders, meaning the the other two lose an extra percentage of their power, and using more fuel! Would be interesting to see if you actually gain anything significant with a conventional valvetrain and throttle.

Edited December 18, 2009 by Cameron

[Galifrey 1]

It's a clever idea, but I reckon you would have to make use of a fully electronic valvetrain to take advantage of it fully. Otherwise you'd be experiencing 100% pumping and frictional losses from two cylinders, meaning the the other two lose an extra percentage of their power, and using more fuel! Would be interesting to see if you actually gain anything significant with a conventional valvetrain and throttle.

 

That is pretty much how they did it I believe, hydraulics operating the valves with electronic control. I can only assume they were non inteference valves

[Cameron 16]

It's a clever idea! Open all 4 valves at once, just enough so they don't touch.

[DrSarty 90 1 Cars]

It's a clever idea! Open all 4 valves at once, just enough so they don't touch.

 

What about a 5th, dedicated valve?

[Galifrey 1]

What about a 5th, dedicated valve?

 

http://en.wikipedia.org/wiki/Variable_displacement

 

 

 

Seems they close the valves completely and the closed cyclinders have an air cushion that is neutral ie loads on upstroke, pushes on down stroke creating no pumping losses.

Edited December 18, 2009 by Galifrey

[Batfink 201]

It's a clever idea, but I reckon you would have to make use of a fully electronic valvetrain to take advantage of it fully. Otherwise you'd be experiencing 100% pumping and frictional losses from two cylinders, meaning the the other two lose an extra percentage of their power, and using more fuel! Would be interesting to see if you actually gain anything significant with a conventional valvetrain and throttle.

 

how about a duel crank solution with an electronically controlled locking diff/clutch to link them?

Edited December 18, 2009 by Batfink

[Cameron 16]

How about running it on angel tears?

[welshpug 1,621]

or diesel

[GLPoomobile 958]

Yeti jizz FTW!

[jackherer 543]

Funny, 'cos that goes against almost everything I was taught in my first year of uni, and also against my Mondeo owner's manual.

I think that you, or the bloke who wrote that article, or both, have got a little confused here. What that article means is that the relative efficiency has decreased, i.e. the slower you are going, the less "efficient" your engine is as you are using a smaller percentage of the power to propel you forwards; this seems to be confirmed when the article mentions zero efficiency at idle. In reality, the slower the engine is rotating, the more completely the fuel burns and the more the engine makes the most of the available cylinder pressure. Hence why truck engines operate at 1000-1500rpm, and why ship engines operate at very low rpm.

 

If you want to confirm this, apply a set amount of throttle and watch your mpg reading go down as the revs go up.

 

Both trucks and ships are diesels with no throttle so if anything you are proving my point.

 

Is this article wrong too? http://www.autospeed.com/cms/A_110216/article.html

 

Using first year uni to try to back you up is not impressive really, maybe you could cite some actual sources? And I don't mean the Mondeo user guide

[DrSarty 90 1 Cars]

Interesting article.

 

Funny how it refers to EGR, as I did some research into it to see if it was worth including on a project of mine.

 

EGR theory mentions 'reducing pumping losses' too, and says - perhaps in a sales shpiel fashion - that EGR systems when working properly reduce emissions, increase fuel economy AND increase power. All seemingly contradictory.

 

Several articles slate it, based on reintroducing non-combustible exhaust gases back into the chamber, which in theory (to me anyway) reduces efficiency.

 

But: if what I said earlier about Sandy commenting once that best economy and best power maps were practically the same thing, then if reducing these pumping losses, either by driving style, using an EGR system or by some other method does in fact increase efficiency and fuel economy, then perhaps we can have our cake and eat it, and get more power too?

 

However I would say it's more likely to be economy orientated than a route to choose for more power, as in adding an EGR system may gain you you 2mpg (perhaps), but almost certainly not gain you 2 or more BHP.

[cybernck 400 1 Cars]

The engine could be mapped 16:1 AFR for high MPG at crusing speed and 12:1 AFR on WOT for max power,

therefore achieving better mpg *and* more power (if the engine itself had been upgraded), but not both

at the same time, ofcourse.

 

I also don't see what's wrong with Megasquirt and its DIY fashion. Unless the ECU itself is playing up,

there's nothing to stop anyone mapping the fuel and ignition tables as good as any other ECU .

 

If it was unavailable as DIY kits and with more features than some other "brand name" ECU's and

cost much more, I'm sure people would class it as a good ECU. For instance, take a look at VEMS.

[Cameron 16]

Sorry, but Wikipedia is not a source and never will be. Any idiot can put an article on that website, and since that one in particular doesn't have any citations then I'd take what it says with a very large pinch of salt. I'm far more inclined to believe a doctor of engineering over some muppet with a keyboard.

 

If you want me to post the lecture slides then tough crap, I can't be bothered.

[Galifrey 1]

The problem is you and Jack are both right to an extent.

 

An engine is most EFFICIENT at 75%+ but that doesnt mean most economical unless you are in 5th gear at constant speed.

 

At lower speeds the gear ratio compensates for the inefficiency of the engine to allow it to be economical at low throttle settings.

 

However, like Jack says, with the correct load and conditions, the engine will be most efficient when it is working hard.

[Jarrus 3]

Correct me if i am wrong but don't most of the current range of aftermarket ecu's have the ability to have 2 or possibly more maps?

 

I'm pretty sure the emerald k3 and the dta s60 has the option,

 

So use one map for economy and one for power, simples

 

I'm also pretty sure they can be switched between simultaneously as well so you wouldn't have to pull over and turn your car off every time you wanted to switch between them,

 

That's what I'm going to do when I get my 205

 

 

mods that yield good torque gains should help as well, like itb's do, I'm not sure on a gti-6 or and mi16 engine but the 206 gti engine (not the 180) has a pritty weedy amount of torque but with a set of 40mm thottles and a new ecu (I looked into the longman conversion for these cars) it has 170 lb/ft at the same rpm as before and produces 150 @ 3500 rpm so surely when you are driving at normal speeds you should see a drop in fuel consumption.

 

Although if you get that conversion done you are more the type of person that will bury your foot more often because you have more power.

 

As for the Mi16 engine, in standard form it's never going to be as efficient as the gti6 because of the pure a simple reason that it is the next generation of engine to the mi16 , don't get me wrong the mi16 is brilliant but like all things the people who manufactured it said " this engine is brilliant, but we need to make it better" so because of the advances in technology and govenments (and the consumer come to think of it)demanding lower emissions and better fuel economy and increased reliablity and due to psa running a lot of mi16 engined cars in the various motor sport teams they had all given there feed back it's inevitable that they are going to make something to fit the bill

 

Weight saving by using a lighter engine doesn't always produce the best results, you have to look at the whole picture

 

Just some thoughts really

Edited January 30, 2010 by Jarrus