M20B28 injectors

[TriggerFish]

Hi all,

I've been slowly planning to look at the map on my M20B28 now I've got a WAR chip for it. (I'm not looking for all out power, this car is just a bit of fun/learning for me - standalone might yield more, but that's not what I'm after.)

Anyway, it's running very rich at the moment on standard injectors, rebuilt by InjectorTune. Much like Kedge's was: http://www.e30zone.net/modules.php?name ... &start=400

I've been looking at injector replacements (mine is also hard to start after standing, so they're possibly leaking too, but I will check this before replacing them for the sake of it), and have considered the M52 ones and the M30 ones. The M30 units are expensive, and the M52 ones need an expensive FPR to achieve the correct pressure/flow rates.

I've been looking around and found the below very helpful spreadsheet, and have noticed that the M52B82/S52 0280150440 injectors look like they might work. They flow ~215cc at 3bar (vs ~150cc stock), and fit right in. This might be more than is needed, but I guess I can back the fuelling off in the map? I guess it's better to oversize the injectors with a low duty cycle than vice versa?

At $90 for a rebuilt set of 6, they're not expensive either... (They're $90 on another website, the eBay link just shows their specs nicely )

Is there anyone that's tried these, or any horrific reason that I should steer away that I'm missing? Being gen 3, but still EV1, they should benefit from plastic bodies and 4 pintle designs, but still keep the same plugs. Resistance is 1 ohm difference to stock, if that matters?

Cheers
Joe

http://www.ebay.co.uk/itm/132057799630? ... EBIDX%3AIT

http://www.usrallyteam.com/content/prod ... r_data.xls

[Kedge]

Mine wasn't running rich, quite the opposite in fact. I just wasn't aware that a car running very lean could smell so similar.

I went for M50 injectors and then increased the fuel pressure. I was conisdering all kinds of Bosch injectors but went for the M50 ones due to being 3 pintle.

Mine still needs a proper mapping session done, but it does run a lot better now. I was also told to run it on super unleaded.

[TriggerFish]

Ah, that's interesting. I didn't know they smelt the same either. We have the same spec engine, I believe, with the same injectors, camshafts, internals, so I'd guess I'm in the same boat you were. I don't have an AFR gauge to verify though.

What did you use to increase the fuel pressure? The Porsche FPR I'm your thread runs to about £70+ new, which .Ales the m50 an expensive route if that's what is required...

Thanks!

[DanThe]

£70 isn't a lot to spend to get the correct fuel pressure considering how much an engine rebuild costs, 4 pintle injectors will always result in a better air/fuel mixture than the old 70's/80's single hole squirters. The old single hole are designed to fire the fuel at the valve, the impact is what atomises it, its like stone age technology

[TriggerFish]

No, I agree, but why spend the £70 if the S52 (216cc @3bar) injectors will do the job without needing it? (Genuinely asking, not trying to be a dick.) The S52 injectors are 4 hole units too, so I see no downsides over the M50 units? Can use standard FPR, and are roughly comparable on price, but flow more fuel.

I didn't realise that the stock units atomised just against the valve - that is crude! I assumed it came out as a spray, kinda like a hose pipe with a finger over the end!

I've ordered a wideband sensor/gauge so I can get some idea of what's going on with things before I order another set of injectors. I'm sure they're needed, but it's nice to be sure. Plus, it'll make using the WAR chip a lot safer rather than tuning in the dark.

[Brianmoooore]

£70 isn't a lot to spend to get the correct fuel pressure considering how much an engine rebuild costs, 4 pintle injectors will always result in a better air/fuel mixture than the old 70's/80's single hole squirters. The old single hole are designed to fire the fuel at the valve, the impact is what atomises it, its like stone age technology

It is, of course, much better if you use a fuel that likes to be a gas, rather than one that you have to try to make pretend to be a gas, and which loses no time in returning to a liquid if given the chance.

[reggid]

forget about getting a new FPR get some injectors that flow enough for your needs at 3b and dont over think it

i always try to get injectors originally fitted on 2V /cyl engines as better chance of the spray angles being suitable, so the injector sprays predominantly on the hot valve (i think 20-25* from memory)which has a better chance of successful vaporization than spraying on the colder port walls. some 4V injectors split the spay for the two ports and other fancy things that probably isnt the best idea on the m20. there are heaps of places in the US selling such injectors as they still have lots of 2V cyl engines