MPi injector information: Response Time
Turbo Mini Forums

I learnt everything i know off Iain...

ha ha, it does the trick at times!! too often according the the EX missus!!!

roll on avon 2006!!

Edited by iain on 10th May, 2006.

Dave, from what I understand, and I dont pretend to bother knowing all the nitty gritty, or doing any calcs...

It seems that 1.0ms is the lower limit for any injector/ecu in order for it to work properly.

I know that when fitting big injectors, you must use low impedance ( peak and hold ) as high impedance are too difficult to control with any accuracy.
A friend has 1000cc inejctors on his Subaru, and they work perfectly. There are other guys with larger ones.
There are some high impedance injectors similar size that work, but generally speaking, anything larger than 750/800cc is a low impedance, as they work better and faster, and can be controlled better.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Steve, What you're saying, is based on technology that isn't completely up-to-date. I've already proven that High-impedance injectors from a decade ago are less than 1ms response.
If talking about BIG as in 750cc+ however - I'm only aware of low-impedance units, so you're forced to use low impedance as that's all you can puchase?

Wonder If those massive-flowing injectors that peter1071s was wanting to use in his could make a detour to Michigan first, such that they could be tested?


Not included in my test esults, I've a set of injectors that are high-impedance ones (these are my secret-not-sharing-this-one-spec) that are operating around 1.5ms faster than the MPi ones. These are around five years old aswell.

Basically - Times have changed, and you can't assume anything. Testing revealls the truth.

Edited by TurboDave16V on 13th May, 2006.

Top stuff :) :) :)

When you've finnished this, do you fancy trying the same with an SPi injector ??????????? It seems that you have the tools, and, there is nothing like having the right tool for the job now is there

Well, that'd be an interesting test.
I'm not willing to pay for one though LOL!

im willing to remove my standard one and post it to you if you'll get it back to me.

I've seen the future and tbh its Pie

Can get hold of a couple of different size injectors and mod the regulator to make it adjustable at the turn of a screw. It would be the whole injector housing and not the TB.

Would be wizzard

Im basing wha I say, on what Ive seen over various forums.

Whether the 1.0ms is an electronic limitation, or a physical one, I'm not 100% sure.
Perhaps that 1.0ms is indeed longer than the valve is open perhaps at idle ?

I do recall a while ago, I found some guys talking about the Autronic ecu/s and their abilities to control large injectors. Again, this 1.0ms threshold was a major thing.

But then I guess the need to go as low as 1.0ms would mean you are running huge injectors.

The 1600cc Bosch injectors are aobut the cheapest huge injector you can get.
I dont think I'd ever consider them for a Mini though.
I know a guy that now suplies 1000cc side feeds for a Subaru, although they are modified high impedance 740's. They seem to work well.

RCengineeering in California can make about any injector you would want.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I hear what you say about BS and experts on forums.

But you can usually sift through it and find sense. The 1.0ms thing isnt just one post. I know for a fact the factory LS1 ecu cannot operate below 1.1ms.

And I have read on more than one forum, that controlling an injector with any accuracy below 1.0ms, just doesnt happen.

I dont recall the forum that made reference to the Autronic, but the discussion was about using the 1600cc injectors as the primarys on an RX-7. Many said it was impossible, but some guys were doing it, with surprising results. Some claimed it was due to the Autronics abilities.

Out of curiostiy..... are you running an intercooler with the methanol ?
Ive heard about a few turbocharged methanol cars, and they didnt use an intercooler at all, and they make some serious power, and IAT's were nice and low.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Steve - the factory ECU probably doesn't need to go that low.
That said - it will almost definately have 0.01 ms resolution, which is more than some aftermarket ECU's have... I'm sure you're aware that DTA in DOS mode only does 0.1ms for example. Use DTAWin and you have 0.01ms resolution. Naturally, I'll be using DTAWin this year...

It's just occurred to me that it's possible you weren't understanding the full reasons behind this testing.
What we're looking at here is not what it'll go down to at idle. No - what I've done the tests to determine is, from the point at which we TELL the injector to open, to the actual point that it DOES open - otherwise known as injector 'dead time' I believe - or delay/response to use a simple engineering term...

This is critical to understand so we can work backwards to establish an accurate 'window' that we can inject the fuel from, for different RPM ranges to maximise the injection pulse-width in the small space available.

Edited by TurboDave16V on 16th May, 2006.

Andy Forrest recently ran E85 in his Subaru to good effect....no intercooler at all. ( 9.77 @ 150mph 1/4 !!!! )

Article on a methanol fuelled V8.

http://www.highperformancepontiac.com/tech/0410pon_butler/

Taking a simplistic approach, it seems like you want to omptimise injection timing for best fuel delivery ?

I was told the easiest way to do this, is to adjust inj timing in the dyno, steady load held, and play with the timing at that point until the mixture reads richest ( without adjusting actual injection pulse widths )
Most injection timings are timed to coincide with closing valve, so that also assists in getting close to optimum.

Although not sure if every ecu is capable of changing the timing at varying rpm's ( I know Motec can, and my DTA cant. )

My P8Pro only allows the use of DTAWin. Although the numbers can go down to 0.01 on the screen, My understading was, that is impossible to achieve in reality.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

It's not just about optimising it for fuel delivery, so much as trying to establish a set window to properly inject into... Of course, I don't have to do this - I can just keep tapping away till the lambda's start saying it's unbalanced, and either up the fuel pressure or use bigger injectors. I want to do things the methodical and scientific (correct) way however.... Also - not everyone wants to purchase a pair of WB O2 sensors, Once i have the data, I can publicise a 'window' that at least works for my setup - others can then follow.
Hmm, so maybe i am looking at optimising fuel delivery afterall... LOL!

Again - you stated that you undertstand something to not make a difference - but I suspect no-one has ever actually done something like put a scope on the output to see EXACTLY what the facts are, rather than just make an educated guess.
Certainly, if your injector has a response time over 1ms, and you're using around 4ms or more at idle, even 0.05ms will be pretty hard to identify any real difference of. You're definately right in that respect...
With our very small displacement, and massive injectors, so long as you had 0.05ms resolution, you probably wouldn't need any more, unless of course, you lived in California!

ps - great link!!!!
Do you still have the LS1 granny btw?

Edited by TurboDave16V on 17th May, 2006.

Certainly do....

Now 6.2, better heads, milder cam now with 73lb high impedance injectors lol.

Running batch fire, I'll admit that initial, impressiosn are the injectors will still be tricky at idle.
I had wanted to go sequential, but sorting a cam trigger is proving difficult, so I had to revert back to batch ( first started new engine on all 8 cylinders about 2 hours ago )
Cam trigger I modified didnt work, so it ended up running on 4 cylinders just.

I noticed a guy over on the DTA forum I recently discovered, using an EXP48, running 96lb injectors ( low impedance too with no driver box ) on a 1300cc blown Hyabusa engine.

He said they idled fine !! Although it is purely a drag bike, so not sure where his idle is lol.

perhaps some of the turbocharged motorbike guys might ahve some insight into injectors etc.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Whats the difference between Methanol and E85 ??

I know methanol isnt very nice to aluminium, and is rather poisonous, but does E85 require any caution ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

I thought ethonal was a problem for ally...

but so far my soocby is fine on Tesco 99 :)


Alex

AlexF

Alex, are you saying Tesco 99 has a large ethonal content? I know nothing about this stuff.

What is meant by Eating ally? I am thinking that for a material to corrode it needs oxygen so putting a material in a sealed container is not replicating the environment you are concerned with, i.e, hot and full of air. However if it is streight chemical reaction between the two (ethanol & ally) then perhaps the washing effect of moving liquid makes the 'eating' worse.

Just thought it was worth mentioning that there is more to corrosion than a still liquid at room temperature.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Glad to see you are keeping up you standards pete, I would have been supprised if you had not thought it through properly.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Being sad is all about perspective. I think a nerdy element is cool. Some people think being on bigbrother is cool, personally I think that is sad, and means you have a banal existance and have nothing to give to the human race, but hay.

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

Was just searching some other forums I use...

Found this one, with some chat about E85

http://www.ls1.com/forums/showthread.php?t=12804

I highly doubt anywhere over here ( Northern Ireland ) will sell the stuff though.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Is it currently available at any pumps in the UK ??

Or where would you go to buy some ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

As dave has let us all in on the MPI injectors are a top bit of kit, I was on ebay and saw what I at first thought were a set of MPI injectors, but then i read the big obvious bit and realized what they really are.

Anyway, point is injectors aint cheap and these may be a good cheap option for those doing a bimmer,7 port, 8port ect.

Hi,

Could someone confiirm the MPi MJY100460 injectors are 340cc/min ?
Are they low or high impedance ?

Thanks

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm

They are actually 460 cc/min and high impedance:

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=10615

I think that Marcel Chichak estimated them to be 340.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Oh thanks Paul. I saw this post but did not notice all this info. This site is so rich that I'm lost most of the time :)
There is a link at
http://www.fiveomotorsport.com/Injector_SetsMODS.asp#cng150
Looks affordable.
I have Maserati high imp injectors but they are only 308cc (as it's a v6)

std 998 A+, g295, MD266, RHF4, 109hp @0.8bar/5400rpm