injectors ???

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gnrsoul
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Post Fri Jul 19, 2013 3:05 am

just a quick question if anyone can help?

are all e30 injectors the same as in can I use m40 ones on a m20 and viceversa, also some e36 injectors look the same as well ???

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Grrrmachine
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Post Fri Jul 19, 2013 6:57 am

They're all pretty much different. IIRC you can use M40 injectors in an M20B25, but you can't use them on a 320i - different impedences. There are also differences between pre- and facelift injectors, due to the engine management.

And the same again for the E36.
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Post Fri Jul 19, 2013 7:03 am

What Injectors could you use in an M42?
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Grrrmachine
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Post Fri Jul 19, 2013 7:36 am

M30 injectors - they have the same funny pintle cap. Although I seem to remember there are two types of M42 injectors, depending on the number of pintle holes. They should be interchangeable though.
gnrsoul
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Post Fri Jul 19, 2013 2:59 pm

thanks for that, So im better off just getting the correct injectors of my engine and getting them refurbished
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Post Fri Jul 19, 2013 8:49 pm

TPS wrote:What Injectors could you use in an M42?
Is there any performance gain?
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Brianmoooore
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Post Fri Jul 19, 2013 10:17 pm

M42 and M30 boat anchor in 2.8, 2.0 and 3.5 form use the same injectors.
M40 and M20B25 engines use the same injectors.
The only job a fuel injector has to do is to meter the required amount of fuel into the inlet manifold near the inlet manifold, and to try to get that liquid to resemble a gas as closely as possible for a short period - this is the principal reason why LPG is so much better a fuel to run a spark ignition engine on. It turns readily to a true gas, and doesn't try to turn back into a liquid again.
BMW chose a specification of injector for each engine that dispenses the correct amount of fuel in conjunction with the software tables in the ECU, so there is nothing to be gained by using a different injector on a standard engine, although a more modern design of injector may make a slightly better job a making a pseudo gas out of the liquid. The effects will be marginal, and whatever injector you choose its characteristics will have to be mirrored by the data in the ECU to keep the mixture ratio correct.
What will give real gains is ensuring that your standard injectors are performing as they were when they left the factory, by having them rebuilt and calibrated.
gnrsoul
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Post Sat Jul 20, 2013 1:36 am

M40 and M20B25 engines use the same injectors.

that's good to know I want to get my injectors refurbished and was looking for a set to run or send away as long as these are the same I can get from both engine if I need to

thanks
Alex
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Post Sat Jul 20, 2013 8:57 am

Cat equipped m40's use different injectors as i found out :)
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Brianmoooore
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Post Sat Jul 20, 2013 9:12 am

Alex wrote:Cat equipped m40's use different injectors as i found out :)
Nothing in the ETK to indicate this. There are Lucas and Bosch injectors listed for all M40s, but AFAIK they are just alternatives.
As someone who has experienced products from "the prince of darkness" for many decades, I know which I'd be choosing, but that's based on prejudice, not logic.
Alex
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Post Sat Jul 20, 2013 9:18 am

The ones fitted to my 1994 touring had what's best described as 3 holes in the bottom where the fuel comes out :)
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Post Sat Jul 20, 2013 9:27 am

Brianmoooore wrote:
Alex wrote:Cat equipped m40's use different injectors as i found out :)
Nothing in the ETK to indicate this. There are Lucas and Bosch injectors listed for all M40s, but AFAIK they are just alternatives.
As someone who has experienced products from "the prince of darkness" for many decades, I know which I'd be choosing, but that's based on prejudice, not logic.


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Post Sat Jul 20, 2013 9:38 am

Alex wrote:The ones fitted to my 1994 touring had what's best described as 3 holes in the bottom where the fuel comes out :)
That sounds like a "more modern design" that I referred to in my first post in this thread.
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Post Sat Jul 20, 2013 4:40 pm

My car is a 1993 with a m40 and it has a cat so I'm getting a bit mixed up here so just to get this right so I don't get it wrong, I can use any m40 or m20b25 injectors and it does not matter if it has a cat fitted or not?
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Post Sat Jul 20, 2013 6:20 pm

These are what what was fitted to mine

Image
not the usual like these

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Couldnt tell you wether you can interchange them

I had some of the above reconditioned and when i went to fit them realised they were different so put it back together
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Post Sat Jul 20, 2013 9:04 pm

A quick 'google' for 'Lucas fuel injector images' brings up loads of pics. that look like you first pic.