After seeing erratic air fuel ratio numbers from cylinder to cylinder on my 502 MPI on the dyno I bought a injector flowing cleaning testing machine after flowing and cleaning the 13 injectors I have I find that there is a 20% difference from best to worst and 5 of them falter at the higher settings and have diminished flow out of all 13 only four come close to matching each other even after extensive cleaning and flowing. Going to just buy eight new injectors flow test them and install them in the motor on the dyno. Will Siemens Deka short style injectors bolt right into a 502 MPI?

found oe style replacements for a real decent price so not worried about making siemans dekas fit. they claim "match flowed set too", i will be flowing them and will post results as soon as I get them, Smitty

Are they similar to Kehein injectors like they used on the small blocks?

bumping the original question- i was looking at the siemens deka for replacements for my 502mpi. is there any reason these wouldnt fit? also what type did you end up going with Smitty?

The only place I've gotten them from for the mag mpi motors was RC engineering. They have a bunch of different sizes, and they come with a flow sheet. www.rceng.com

i bought a set of the yellow stripe ones that had same interchange number/partnumber as merc originally used online this morning from DIY-TUNING, he claims their flow tested too, we'll see.

I have ran the short siemans deka short ev-1 14mm before, had a spare one here but cant find it. They are really close in dimension from what I saw online but not sure if direct fit. after what I've seen on the injector flow bench I bought I would NOT buy a set of injectors ever again that weren't flow matched and will still flow them anyways. The big fail on these merc ones I have is once you turn PW to about 8 or 10 ms and rpms up to about 4500-5000 they LOSE flow on a few, thats after cleaning and flowing them 20+ times to straighten them out,they were worse. 13 of them and I can only cherry pick 4 that are 4% apart or closer. I can'r believe these efi motors dont melt down left and right, there is a reason Merc makes tunes so f'ng fat I guess. I will be SERIOUSLY re-considering how "cleaned up" I want to tune efi motors if injectors are going to progressively act smaller and smaller but NOT uni-formly!!

interesting. looking forward to results.

Flowed, cleaned then re-flowed a set of hp500efi injectors today. They started out real screwed up, evened out somewhat (about 2-5% difference at 40 psi) after cleaning except one weak one that just doesnt keep up. They definately act much different than the mpi injectors or siemans deka injectors. They literally stall at 65 psi and just shutdown. I'm seeing a pattern here too, 3rd set of injectors i have tested, even though the flow increases at higher pressures (which I have done for years-raise fuel pressure to make injector act bigger) the 3,4, 5% between injectors turns into 8,10,12% at 60+ psi so raising fuel pressure can get you more flow but at least on these used injectors it starts really screwing up the balance. I am real anxious now to see how these new ones are going to act!!!

To answer your question Smitty, yes the Siemens Deka shorties will work just fine in the later model fuel rail. Done it many times. They obviously will not work in the earlier rail that used the Keihen injectors.
Eddie