Leeroy_25

Please ignore my previous post with wrong injector size!
Now I think I have the timing Sussed I am still having a issue with rich idle.. I cannot get idle below around 10.8-11.2 AFR. It is definitely rich and a bit smokey like this but if I try and go down even a click on the idle mix it starts stumbling and stalls. It is like the injectors stop? Is this a common problem for big injectors on idle. I have 1600 cc secondary and primary with microtech ltx-12. Should I be able to get better cleaner idle with this or do I need to use some tricks? How much advance can I add in at idle before it's a problem. I know this will help but maybe only a bit. It had around 15 degrees advance before from static and idle was still rich.
Can I close the firing gap on the plugs up?
Raise or lower fuel pressure?
Anything else anyone can suggest.

Thank you
Lee

hsmidy

Older larger EV1 injectors have been noted to have issues when injecting low amounts of fuel.
Any reason why you didn't elect to go for EV14 injectors?
Whats your rail pressure at idle?

fritts

iTrader: (5)

I was able to lean out idle on EV14 2000 injectors but the old indy 1600's just would never be able to lean enough for an acceptable idle afr. Change your primaries per above post... 1000 cc ev14's would be a good start.

Leeroy_25

Thanks guys for the feedback. I am starting to conclude this is the issue. I got the injectors a while ago for a good price with a rail and bits. They were from drag car! Being that my power goal is 600bhp flywheel with about 1bar boost if possible I guess 1000cc primaries with the current 1600cc left as secondaries will be more than enough injector. Just need to find out if the Microtech LTX-12 will be okay with that and if I need to match low impedance primaries or can use high impedance as I gather they work better at low flow? Thought the ev14 were high impedance?
Will these just drop right into my current fuel rail setup? Will they need the injector spacers I have fitted or do they fit without? And if the latter do I need to put the OEM injector diffuser things back in the injector holes? What other decent injectors for a good price are there that will be a simple straight swap? I have seen ones for evo engines and a few other types on fleebay that look like they could fit but have no idea what's good or not over there. I will no doubt buy them from USA!
RC injectors I think is another option but they look just like the Bosch EV1? I assume newer and better tech though?

Thank you
Lee

BLUE TII

iTrader: (9)

Yeah, I tried to idle/run my car on my 2x 720cc and 2x Bosch 1600 (EV1) to avoid staging issues.

It idled and kinda ran, but the idle to driving transition was fireball shooting rich and the low load fuel trimming was far from precise enough to work that out.

Leeroy_25

But that is quite a big difference compared to stock? So 1000cc with 1600cc is closer to the stock ratio? I could change all to 1000cc if it is going to be essential to do so but think that is then cutting it fine on injector capacity and I don't really want to shell out for another 6 injectors!

Thanks for input..

fritts

iTrader: (5)

I won't tune microtec so I have not idea why you would worry about the ratio of primary to secondary. The primary's are the only injectors firing at idle. Transition can be tuned easy enough on the Haltech's. If 600 hp is what you want then you need more than you have currently anyway. I would go 2x1k primary and 4x2k secondary's for pump.

Leeroy_25

Tanks for the reply. I think you may have misread something and be quoting figures for a 13B setup?
I have 20B and currently have 3x primary 1600 Bosch EV1 and 3x secondary 1600 Bosch Ev1. That's a total of 9600cc.
I have read that you need about 1000cc per 100bhp rear wheel. I am aiming at 600bhp flywheel. My old 13B made 420bhp flywheel on 4x850cc stock injectors. So following the same rule of thumb I have plenty of injection at the moment.
Hence my plan was to come down to 1000cc primaries or maybe a bit lower and leave the 1600cc secondaries as they are. My only concern about the size ratio is I have read that big difference in size between primary and secondary can cause difficulty getting a smooth transition when the secondary injectors kick in. Could be just a Microtech thing. hence if I can definitely get a good idle with 1000cc and keep the ratio between the two closer it makes sense to go that route.
Are the stock Secondary 20B injectors 850cc like the 13B engine? I wonder if I could mount these in my rail and use them? Cannot remember off hand which are the top feed on the 20B and if they will fit the rail anyway?

Thank you
Lee

hsmidy

20b is 550cc all round factory, top fed are the secondarys.

Leeroy_25

Okay.. Thanks for confirmation.. So that won't work!! I am on the look out or some 1000cc then I think.
So as I can see the options I have are the following:
RC Engineering (look like straight swap for current EV1's)
Injector Dynamics
Bosch EV14
Grams
Denso? 4 x 1000cc fuel injectors for Impreza WRX and STI Forester Genuine DENSO e85 | eBay

Would like to get some feedback on the options and what is going to be a straight swap over what I have with the same rails and adapters. Or rails and no adapters of course!?
Also I need to check if I can mix High and Low impedance injectors on the Microtech LTX-12? I believe the EV1's are low impedance. but i gather High impedance offers better performance low down?

Also on a side note I checked my fuel pressure this evening. With key on but engine off the FPR gauge was reading 50psi or a nats under. Don't recall setting it that high.. Should it be set with engine at idle because it drops a bit? I cannot remember off hand what I did now!? or if I did it right in that case! I gather 43.5 is recommended base pressure normally from recent reading? don't know if 50psi will cause an issue if that's what is holds at idle or if it is just as well left as is? i was wondering if dropping pressure a bit might help idle for now? but then I am really feeling the new injectors are the way forward anyway.

j9fd3s

iTrader: (3)

i forget where i read it, probably injector dynamics, maybe here, but the EV1's can only go down to like 1.5 ms pulse width. going lower gets unstable. i think the ev14's go to like 1.2 or something?

stock is a 550, running we'll say around 2.25ms, so it makes sense that the engine would be rich at idle.

Leeroy_25

So question now is with my microtech will I be able to get a good transition if I run 1000cc or maybe even smaller. Say 750cc primaries and keep my 1600cc secondaries. Some say it will be fine and some say not by the look of it? If I am getting new injectors to get a better idle it makes sense to go as small as I can before I start running into transition issues when the secondary's come on? 600bhp at flywheel is modest so I have way more injector ability than I need at present!
Thoughts please..
Also would you go RC or ID injectors. RC are cheaper and straight swap for my current Bosch. Are they good a reliable though? ID do a nice kit but I gather my Microtech won't make full use of their fine ability!