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RPM dependent Staged injection (and possibly autotune?)

Posted: Thu Sep 24, 2009 9:43 pm
by deuce_454
I am fitting a gsxr 600 f7 TB/injector to my 1071cc honda CB750 sohc and im trying to setup my fuelmaps prior to startup.. but im having some difficulties deciding what to do....

The gsxr TB has dual injectors and switches on the original application from the primary injectors downstream of the throttleblades at low rpm to the secondary injectors upstream of the injectors at high rpm.. i want to do the same..

I have a couple fo strategies and im not certain of which one (if any) of them is the right one, One would be to flow test the injectors "in vitro" on mt workbench.. simply fireing each one into a measuring cup for 60 seconds and note the flowrates in cc/min.. then tuning the bike using one set only.. and then setting up 2 VE tables. one from 300-4000 rpm and one from 4001 to 11000rpm .. is this even possible? would they have to be the same.. with rpm bin 300, 1000, 2000, 3000, 4000, 4001, 5000, 7000, 9000, 11000. and one table have value "0" above 4001, and the other below??? .. and can autotune handle this.... and what if i did an alfa-n blend above map tps 50-75% where the map is going to be close to maxed out..... can autotune handle this???

Re: RPM dependent Staged injection (and possibly autotune?)

Posted: Fri Sep 25, 2009 2:29 pm
by 24c
IIRC You can use "dual tables" for staged injection on the MicroSquirt, but not sure if it'll do 2 x four injectors. If you do a search you might find out more.

Re: RPM dependent Staged injection (and possibly autotune?)

Posted: Fri Sep 25, 2009 9:58 pm
by deuce_454
according to the litterature it will handle 2X4 high impedance injectors just fine.. a o value in staged mode equals zero injector opening.. so according to what i can reat it should be possible... my question is can i turn one set on, and another set off at a given rpm/load and not have the engine stumble ?? how should i set up my VE tables so they turn of/on simultaneously... (i know there should in theort be a small x-tau correction when switching from one set to th eother as the injectors wet a different portion of the port... but that is not possible as far as i can see)

Re: RPM dependent Staged injection (and possibly autotune?)

Posted: Wed Sep 30, 2009 3:25 pm
by Andy_Stprbeck
Seams like you might be better off to blend the two sets of injectors together for a portion of the table, so the transition isn't so abrupt.

So if you wanted the changover at 4000 rpms your two sets of rpm bins would be something like this: where the "% of total fuel" is the percent of the total fuel required at that rpm bin that is injected by that set of injectors.

inj set 1 rpm____________300,500,700,1000,1500,2000,2500,3000,4000,5000,6000,7000
inj set 1 % total Fuel______100,100,100,100,__100,_90,__80,__70,__50,__30,__10,___0

inj set 2 rpm____________________________1500,2000,2500,3000,4000,5000,6000,7000,8000,9000,10000,11000
inj set 2 % total Fuel_______________________0,___10,__20,__30,__50,__70,__90,__100,_100,_100,_100,__100

Not by any stretch of the imagination am I an expert on the subject it just makes more sense to me to not have the abrupt transition at one specific rpm. This way you could drive around at the transition point of 4000 rpms all day and not have a problem.

I have absolutely no idea about the autotune thing.