Injection Correction Factor - Any ideas?

[AC]

Today I have swapped out my 310cc injectors for 440cc injectors, in preparation for intake cooling (soon to be fitted) and a final map session.

After fitting, I reset the stock ECU, then on the Greddy EMB software went to adjust the injector correction factor.  When I opened the relevant box it had already preset 280cc to 260cc giving a correction factor of 1.077.  This instantly seemed strange as 310's are fitted.  I can only conclude Noble were struggling with fueling during mapping and set it this way to push the injectors more.

Anyway, I have tried 280 to 440, 310 to 440 and 260 to 440.  The car starts but isn't right, making a "shh shh shh" noise at idle.  It will rev but is still lumpy.

Any idea's as to what correction factor I should use???  Or could it be that being mapped with 310's yet the EMB told 280 down 260's has introduced a whole different scenario that the injection correction factor won't put right???

[Tem]

When I opened the relevant box it had already preset 280cc to 260cc giving a correction factor of 1.077.  This instantly seemed strange as 310's are fitted.

That is actually quite common. It's not right, but many do it. I'm not sure if that's because the tuner doesn't know about injector correcting, or just doesn't bother to set it properly. Instead they just tune the fuel table to get the correct mixtures.

It works just fine like that too, but makes future injector upgrades a bit harder.  s:? :? s:?

Any idea's as to what correction factor I should use???  Or could it be that being mapped with 310's yet the EMB told 280 down 260's has introduced a whole different scenario that the injection correction factor won't put right???

That's pretty much it. You can set it right with the proper correction factor, but I have no idea how to set it in eManage.

If you had PFC and went from 310cc injectors to 440cc, while the 310's were marked as 260 with a factor of 1.077, you'd have to insert 1.077*310/440=0.759. Might wanna try that with the eManage too, though I'm not sure if that is similar.

[AC]

Tem, your absolutely spot on!  In between my post and your reply I sat down with a piece of paper and came to the conclusion that;

310cc's with a correction factor of 1.077 was in essence asking them to be 334cc's (can't exactly comprehend that as why would we use bigger injectors if you can force a 310 to flow 334 (clearly you can't)).  So I entered 334 to 440 in the EMB correction box and that gave a factor of, wait for it, 0.759  s:wink: :wink: s:wink:  

Started it up, sounded better straight away, still a little 'shh shh shh' at idle, but tons better.  Just gave it a run and OMG  s:shock: :shock: s:shock:   s:shock: :shock: s:shock:    s:shock: :shock: s:shock:    it was kicking like a mule, like never before, twitching noticeably at 3000rpm on boost and WOT.  Now that's what I'm expecting from a turbo.

Clearly those 310cc's just weren't up to it.  Not sure if its now detonating/pinking at 4 - 4.5 or whether the coolant return T is just rattling around the compressor outlet pipe, with the more vigorous boost.  Going to wait till the roads are quiet tonight and give it a slighter longer run in higher gears over 4k.

[spit]

Glad you got sortedish Andrew.

That idle oddness may settle as the ECU starts to intervene based on airflow and O2 readings.

You may be able to help it along by tweaking the idle airflow numbers ever so slightly in the top left of the map. Getting that AFR gauge fitted would help no end   s:wink: :wink: s:wink:  


Don't bother with the EMB anti-stall option. Its not fabulous.

[AC]

You may be able to help it along by tweaking the idle airflow numbers ever so slightly in the top left of the map. Getting that AFR gauge fitted would help no end   s:wink: :wink: s:wink:  


Don't bother with the EMB anti-stall option. Its not fabulous.

The airflow map at idle is set to -2  s:?: :?: s:?:

Wouldn't know the anti-stall option if it hit me in the face..... Ignorance is bliss  s:lol: :lol: s:lol:  

Of course your right about the AFR gauge, was thinking exactly that today when it wouldn't run right. I'll get round to one,  just have intake cooling higher up on the priority list.  I am a little concerned that I could be driving around on a map that isn't now 100% safe due to the 440's?  My fueling needed sorting though with the forthcoming intake cooling, and as I'll be back at Noble within the month I hoping I'll get by  s:flame: :flame: s:flame:

[muffdan]

Glad to hear you've gotten to the bottom of it sounds like it's putting a smile on your face now! All you need now is a 'touch-up' tune and you'll be sorted!

[AC]

Well, gave it a longer run tonight and it's detonating/pinking/knocking (whatever the right term is  s:?: :?: s:?:  ) terribly around 4k rpm upwards.  I mean really audibly 'tingling'  s:crazyeyes: :crazyeyes: s:crazyeyes:  .  Needless to say I backed off and just ran it mainly up to 3k on the basis that the stock ECU would be taking care of most of it up to that level.  I guess injector swap even with some correction factoring still totally screws the tune.  Interestingly the 'thrust' I noticed yesterday at 3k wasn't as evident.  Again I suspect the stock ECU is now trimming its boobs off to get things right.  Idle sounded A OK though.

So I'm back to mainly parking it up.  No great shakes, my intake cooling will arrive this week which should mean final Noble set up at month end.  Hopefully then I'll have all 5 stars on my McDonalds turbo badge and I can draw a semi permanant line under all this modifying lark  s:lol: :lol: s:lol:  and just enjoy the thing.

[ChrisGB]

I am no expert in setting up turbo'd MR2s but I think that something as big as a change of injector capacity would warrant an immediate re tune.

Running lean could hurt your plugs / pistons / valves. Running rich could hurt your cylinder bores / pistons / rings. Surely best to fit all the stuff in one hit and go straight on the dyno?

Chris