630cc injectors
Turbo Mini Forums

I have seen these Hi-z injectors on ebay. Thinking they will be about right for staged sequential injection on my engine (aiming for 130-150bhp max).

Anyone else used these, or can give a better recommendation?

http://www.ebay.co.uk/itm/4-Fuel-injectors...nEAAOSw8w1X~wII

Assuming that your are going to use port injection, then they would be around the right capacity.

I've not used that type though. Mine are mostly Siemens Deka equipped.

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."

Perhaps a simpler route to start with would be to use 2off Siemens Deka IV 875cc/min (FI14992).
You should get close to your target power without the complexity of modifying the MPI inlet manifold or setting up staging.
It does mean running high duty cycles, but I achieve ~147Hp at 24% duty. Way above what I had planned for duty cycle, but that was at a common AFR of 10.7, so the duty cycle would be less if I'd had a leaner mixture.
Tick over is fine with these injectors at around 13 - 13.5 AFR at 900RPM for my 1310cc.

’77 Clubman build thread
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=618189

Siamese 5 port EFI testing
http://www.turbominis.co.uk/forums/index.php?p=vt&tid=611675

Again, making the assumption you are going to be using siamese port injection, I agree with Paul that the total capacity (staged) is OK, probably a bit more than OK, but as Graham says, and particularly for your proposed BHP, a simple non-staged setup with just a pair of larger injectors might be better.

I know from much discussion with Graham that staging is troublesome if the injectors are in different positions and/or different angles (not sure what you are intending but I don't think you would get the larger body ones side by side and parallel).

I currently have 2 x 1000cc Honda Race injectors (can't remember the part number) as I haven't finished my staged manifold yet and, again, they idle absolutely fine despite their size and hence tiny pulse width at idle. They are however low z - a personal preferenece - which, in theory at least, gives much more accurate dead time (although many would say modern high z is just as good).

EDIT...

Just realised this follows on from a thread last month...

How are/were you intending to place them for staged to get the distance/angle reasonably symettrical.

I'm not saying it can't work but it would be interesting for several of us to see how you are approaching the problem particularly if you use injectors that are large in diameter (so hard to mount parallel and at the same distance).

Edited by Rod S on 11th Nov, 2016.

Schrödinger's cat - so which one am I ???

Okay. So that's a surprise, I thought even at the lower power figure I would need 1000cc capacity or more. If I can get away with a pair of injectors that makes life easier, and also reduces cost.

There are many "calculators" out there on the web but they all assume standard batch or sequential injection on an 8/16 whatever port engine so are based around an 80-85% duty cycle.
Once you look at the siamese code it is very different.
If you use the code as intended they open twice per cycle at hopefully less than 25% each time. Or you can overlap the opennings in the hybrid mode for 50% or more once per cycle.
The real issue, as per another recent thread on non-port injection, is IMHO the actual open time, not the computed pulse width.
My computed and commanded pulse width is about 1.2mS at idle.
Over half of that is the specified dead time (injector openning time as quoted in TS) for my injectors.
You need to read the right chapter of the MS-E manuals to understand the real definition of dead time, it's not just open and close because the flow between openning and closing isn't linear, but it makes a real difference to injector choice/sizing once you are in the really small pulse widths of the siamese code.

Schrödinger's cat - so which one am I ???

Mine are Siemens Deka 65lbs, 1 per injection port, so two in all. Enough for 100hp not much more. Excellent injectors ! I tried 2 other types before these ones and the difference in partial loads was huge, very smooth ride now.
PS: mine open 50% of time, I've got my own ECU, not MS based.

Edited by alpa on 11th Nov, 2016.

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

Injectors are kind of important. Buy a reputable brand every time....not un-named ebay shite.

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