Does anyone on this board mess with M30 injectors?

[genphreak]

Anyone got any injector changeover stories or test data to add to the attached document?

I mean for those that upgrade the cam, add some forced induction, extractors, etc. Anything major like that will render the old injectors a bit over-stretched...

Thing is, it is not a back-yarder's science from what I can see. Plenty of people change them, but the results are not clear; I've read about many projects some of you may already be familiar with in my research. The most (publicised) of which in the BMW online world is the fabled Mustang injector 'upgrade' which a lot of people do as these injectors are a little cheaper to buy.

I have an E34 and my injectors look pretty tired at 17 years old. Was thinking about rebuilt or new ones and started looking into it.

It is clear there is confusion out there.... my research so far shows it is not as simple as some make out - the manufacturers don't seem to make much info available.

Facts for Bimmerheads;
Motronic M30s have 2 types of injectors Source (Bosch).

The Mustang conversion seems to work (so many say) for the older E28s (Motronic 1.0) cars and coupes. Beware however, The E34 is a different kettle of fish. The injectors on these Motronic 1.3 cars changed just before the E34 was introduced (ie some are also in the later E28 535is) at the same time as BMW upgraded to Motronic 1.3 ( these injectors are of a higher flow type... (E34s were bigger and heavier).

I say this as I have read about several poeple doing the Mustang injector conversion to E34s, and my research shows this to be bad. I've collected some data from Bosch, Accel and various online sites (cross referencing manufacturer's specs also) to create an M30 comparison chart so you can see what I mean...

In the chart I have described only the rudimentary specifications, I am not knowledgable to compare flow patterns, pulse rates etc which **will also vary greatly** from injector to injector.

It is clear to me from the injector specs (attached) that Mustang injectors would be a bad thing for a Motronic 1.3 car (ie E34). Mustang injectors have a 19lb/hr flowrate, but a stock E34 injector provides more; 20.35. Motronic 1.0 cars on the other hand use a 17.6lb/hr injector, so the Mustang injector might improve things here if your engine is modified and needs to drink more fuel.

What I can say is, based on a day's research, I am sticking with the stock injectors. If you wonder why I think it is so complicated, bare in mind the list I have attached is only of injectors of similar specification. Also, be sure to have a look at the software behind products like these which are used to test injectors in various applications Megasquirt and Engine management Wow this sucker runs a 25L V12...

What I do hope its that the attached list might help others in the community evaulate different injectors and avoid costly mistakes. I am a little dubious about the claims some sites make... has anyone bought these? For example, FiveO claim to have OEM injector 'upgrades' see FiveOmotorsports

Anyone got any injector stories or data to share on the issue?

A note on the list- Don't buy off it... please bare in mind that I created this list on injector specs alone and have not compared the injectors physically or made sure they fit and work.

These injectors may be physically different or incompatible with an M30, even though they are shown in this first version of the list!

[genphreak]

Ahh I forgot one thing...

The 3.6L M30 powered M5 (S38) uses the Bosch injector 0-280-150-701

lbs/hr ccs/min PSI BARS Impedance
22.85 240.2 ? ? High

Common to Alfa v6-3.0l, BMW 6-3.0l, 6-3.5l, Citroen 4-2.0l

Seems like a good upgrade for a very warm M30. I don't know the fuel rail pressure the M5 runs, but given Motronic 1.0 cars are 2.5bar and Motronic 1.3 cars are 3.0 bar, I'd guess they remained at 3.0bar on the M5 and simply increased injector size, perhaps explaining their share of the additional fuel consumption in the M5)

GP
Does anyone know the flowrate (lbs/hour) the Mustang (FOTE-D5B) injectors acheive when running under 3bar of fuel pressure? Or else their type III equivalent (0280155710-F6VE), any Ford injector specs would be nice really...

[Kalevera]

Good info, man!

It was my impression that the stock lucas/bosch ran like...16#hr. I think I picked that off of Don Gale's page, but I forget.

Perhaps the "smooth idle" that so many note from the 19# mustang injectors is due to the fact that the injector is newer and cleaner, with an improved dispersion pattern, versus "better".

best, whit

[Robin-535im]

Apart from better injector design (I recall something about a 'pintle' that is 'better' in the Mustang injectors) your fuel pulses will be adjusted to make the air/fuel mixture correct for emissions (14.7 a/f ratio).

So even if you get bigger / smaller injectors from stock, the Motronic will just open them shorter / longer, respectively, to make the amount of fuel injected match the amount of air.

If you're at redline and gulping gallons of air, you could argue that a higher rated FPR and larger injectors will allow you to fully utilize all that air whereas stock units would not. But at lower RPM's, theoretically, there should be no difference apart from better atomization from newer/cleaner injectors.

That said, I have the 19# Mustang injectors and a 3.5 bar FPR. I don't notice a difference, but mentally I *feel* more prepared!

[genphreak]

That said, I have the 19# Mustang injectors and a 3.5 bar FPR. I don't notice a difference, but mentally I *feel* more prepared!

Great point about the pulse rate coming from the ECU. I guess I'm really nervous about swapping my injectors when those wonderful BMW engineers have spent so much time messing with so many details regarding combustion efficiency, etc... I can imagine them getting it just right after months of work and then being dismayed at us for changing such things around at the drop of a hat (if one looks into those links I posted, you can see those computer systems are used for injector engineering as they log huge amounts of verbose output from the engine as well as controlling settings). An engineer I spoke to told me about using such things..

Good point also about 'Four point' pintles too- I am unsure if the stock injector isn't like this anyway, they are both Type II injectors after all... (?)

Thanks for your input guys, that's good to know. Under 3.5 BAR the Mustang injectors could well flow as much as the stock injector or maybe a tad more. I guess I'd love to be able to add the specs into the chart though to compare.

As it stands from our chart of similar spec injectors for the M30, the Accel AX150 looks like a smart option (if it physically fits an E34) as the specs are very slightly higher than the stock injector at the stock 3 BAR pressure.

Out of interest, where does your 3.5 BAR reg come from, is it for the M5's S38 engine or aftermarket?

GP

[genphreak]

Good info, man!

It was my impression that the stock lucas/bosch ran like...16#hr. I think I picked that off of Don Gale's page, but I forget.

Perhaps the "smooth idle" that so many note from the 19# mustang injectors is due to the fact that the injector is newer and cleaner, with an improved dispersion pattern, versus "better".

best, whit

Not sure about the 16lb spec... can't find anything on that anywhere....

But I have an update which clarifies things somewhat.

Apparently the stock Mustang injectors measure 19lbs/hr flow at 38psi.

The Mustang injector will flow a very similarly amount to the stock injector when running at 3.0 BAR (43.5PSI) fuel pressure... it would get theoretically 20.329 lbs/hr by my calculations. (Stock E34 M30 is 20.35 lbs/hr)

[genphreak]

Hey Robin,

I found seemingly good info that suggests the Mustang injectors are rated 19lbs/hr at 38psi.

I've no idea if this is correct, but if it is, at 3.5BAR your injectors will be putting out upward of 22lbs/hr- I guess this might somehow affect fuel economy or emissions, but you are happy with it? Have u a big cam or anything that wil make it drink more?

Then again, perhaps greater flow is somehow limited by the Motronic keeping an eye on combustion.

But perhaps we need something to back up that 19lbs/hr @ 38psi information, does anyone know?

The site above states "To understand the fuel pressure effects on delivery simply take the square root of the ratio of pressures and that will tell you the fuel delivery gain. Please note as the fuel pressure goes up, there are other problems that occur which will affect your cars performance.

I.e. 19#/hr injectors (stock) calibrated at 38 psi, @ 45 psi=20.67#/hr, @ 55 psi= 22.86#/hr, @ 61 psi=24.07#/hr., @ 95 psi=30.04#/hr.

Elevated fuel pressure can hurt your performance because of increased forces in the injector making it open more slowly and close faster. This may cut down the net fuel sprayed by the injector. If fuel pressure gets too high, the forces from the Electro-magnetic portion of the injector may be too feeble to open the injector and a complete loss of fuel may be experienced,

The best way to affect fuel delivery is to use standard pressure and a larger size injector"

Hmmmmm. I think we could all do with some clarity on what injectors to use. Robin, did you ever run your Mustang injectors and a 3BAR (43.5PSI) FPR?

GP

[gale]

Out of interest, where does your 3.5 BAR reg come from, is it for the M5's S38 engine or aftermarket?
GP

It's a Bosch part number 0 280 160 263 and was used on 89-91 Porsche 944S's and 90-92 VW Corrado's (GT? VR?). It is a direct bolt-on replacement, with the only distiguishable difference being that it's yellow zinc di-chromate plated instead of black paint.

I installed 19 lb/hr Mustang Series II injectors about 3 or 4 years ago and went from a 3.0 to 3.5 bar FPR about a year ago. As Robin said, I think the biggest advantage with the Mustang injectors is from being new and having a better dispersion pattern/smaller droplet size. I did note better top-end performance on mine vs. the Lucas disc-type injectors that were in it with 145k miles on them. One thing I notice with the Mustang injectors is being the pintel-type design, they crud up faster than the Lucas disc-type design. I run 2 oz. of Amsoil PI injector cleaner with almost every fill-up. If I skip it a couple tanks in a row, the idle goes to ****. The Lucas injectors didn't suffer much from that & rarely required injector cleaner.

There was a very slight (perhaps a placebo effect) improvement with the 3.5 FPR, in the mid to high range. I'm running Mark's -179 EAT chip and it rev's like a dentist's drill and easily winds out close to an indicated 7000 rpm if I'm not paying attention (don't do that to often), with an otherwise stock motor with an e28 flywheel & a 3.91 diff.

I gave little or no engineering thought to these mod's & did them for the most part out of boredome, having nothing else of significance to do with my time & wanting to wrench on it just for the fun of it.

[Robin-535im]

Robin, did you ever run your Mustang injectors and a 3BAR (43.5PSI) FPR?

GP

Yes, for a few months. I bought the car with the Mustang injectors so I couldn't compare before/after for those, but even with the different FPR's I didn't notice a difference. Well, the placebo effect notwithstanding .

I have an upgraded cam, perhaps a "271" (although I really don't know what the number means, apart from the fact that other people have "281" and "291" cams, and this one is supposed to be one notch more tame than the "281".)

I'll have to get some FI cleaner though, after reading Don's post.

[genphreak]

Thanks guys,

(That's a sweet looking E32 u have there Gale, if only I could find a 5-speeder here in Aus like that...)

Those are interesting responses... my car has the Bosch type standard, thank God it doesn't have any Lucas stuff on it... it took only 2 years to rid my Mother's car of all her Lucas wizadry- and that was waiting for it to fail before changing to Bosch parts. It hasn't failed her since. Hopefully those Gods of Darkness (Lucas) have gone to find more willing victims...

My pintle caps are certainly very dirty, and are disintegrating from old age I guess. ~ However I have no idea what the injectors are like inside... except theat the tops of each of my cylinders look the same, the spark plugs look healthy and so on. Have you ever checked your injectors with a microscope or does the crud on the pintle cap matter? Perhaps if I change my caps they will only get dirty again... I'll report back on this. I've used injector cleaner intensey a few times beofre oil changes in the past, never noticed much difference though- will try to find some of the Amsoil stuff (Our brands are all different in Oz).

Its interesting that the 'stang ones are fowling up quickly though. What kind of gas to you use? Down here in Australia the go at the moment is NOT to use shell or Mobil for to these reasons...

I think for the moment I'll get mine rebuilt... that should do me ok until I can fathom what to do, I wouldn't mind trying some 'stang ones with my stock 3 BAR FPR, however when you look into it now they do these Type III replacements for those to make things even more complicated... which have a slightly higher flow rate. I'm assuming you don't have these ones...?

If you are not aware the type IIIs are yellow btw (Part number 0280155710-F6VE) and the diameter of the body is pretty much consistent all the way up, unlike the fatter Type II designs.

Perhaps I should email Robert Bosch himself to find out the good oil... LOL

Oh well, its off to get my head back form the machine shop and put my baby all back together again...