can someone help me out i got some deatswerks 850cc and i need some help with the k multiplier i just cant get it right. i have an HR and the stock value is 26808. 22500 idles fine but you cant even get on the throlle. 17400 you can get on the gas but AFRs are way too low sub 10s and wont idle nice. and anything below that wont idle at all

 

you probably need to adjust more than the k multiplier. you will need to adjust injector latency values(look up for your injectors and adjust), injector minimum(~1.5 will probably work), and the K multiplier to just get it idle. Bigger injectors=lower k multiplier so for something that size you will probably be in the k-values of ~13 -15000 maybe lower depending on fuel pressure etc. you will need to adjust all the MAF values as well to scale it based on your air flow as K-value/injector latency will only give you a base to start off. you will also have to play with cranking enrichment and priming pulse to get it to start up nicely on hot/cold starts.

 

i did adjust the injector latencies already based on what they say. i think the thing that messed me up was i wasnt expecting to have to change MAF values since the only thing i have changed at this point are the injectors but i will try that and hopefully it works out well so i can start building my turbo build

 

changing injectors will take a LOT of tuning especially to injectors that large. you will probably encounter starting issues as well unless you dial in everything ive previously mentioned. the MAf values will only really help to AFR's upon acceleration when more air goes through as changing the injectors will exponentially up the amount of fuel going in.
Running rough may also be due to injector minimum being too high(if you havent adjusted it yet).

Changing injectors though a simple physical install is a huge undertaking for proper tuning to run good especially if you don't know all the parameters that need to be adjusted and how to adjust them.

you could probably have gotten 440's running with simply adjusting k value but anything larger needs more tuning, and the larger you go the more adjustments to other parameters need to be made.

 

honestly i just cant get this ****, my injector min is 1.3 like deatschwerks says and ive tried 2 different sets of injector latencys both .84 at 14v like the site says and 1.35 at 14v which seems to be what everyone else uses. im not sure ifs its just cause its an HR but i cant get this ****. ive tried like a millon different k values and it wont stay at idle right it does like a big cam sound. ive tried messing with w MAF values today which made it run better but not idle any better. and also whats wierd is normally the target AFR on decel is 30afr and im getting 60afr everytime im off the pedel while decel

 

Start back over and set the k multiplier at 21860. Set your target afrs the way you want them and from there adjust your compensation table. Increase or decrease the area you are tuning. Set your cranking injection up by selecting the whole table and multiply by .65 and flash it. See how it starts. If u have to crack the throttle then you have too much fuel. Repeat til u get it right. Add fuel my multiplying by percentage.

 

I wouldn't recommend this method especially since the Op is not familiar with tuning. adjusting the compensation table will make things way more complicated to create a base tune for. I would recommend the K value at 7458 and go higher if need be to get it running smoother. I used the calculation of [290cc(oem)/850cc(new)]*21860 to make up for the size difference. That is based on running stock fuel pressure. also adjust target AFR's to what you want. you will need to play with the starting enrichment/priming pulse to get good starting. to get good AFRs while driving that will take playing with MAF voltages. use the .84 injector latency and make sure you adjust the latency drop/volt correctly aswell.

If you dont have a proper wideband getting dialed in will be very difficult and without a dyno it may be hard to get your driving AFRs dialed in unless you have an empty road u can go to and drive up and down watching AFR's and adjusting till you get it.

I would not have installed the injectors alone, and would not recommend you to do the kit install piece by piece. get everything and do it all at once as you will constantly have tuning problems if so.

 

Assuming you've got the scaling correct, you probably need to tune the MAF table if it's aftermaket. Not once have I been able to use a built-in MAF table (e.g. HPX/GT) without some pretty major changes especially in the idle/low load voltages. Trying to compensate for MAF error on the fuel compensation table will cause other issues like timing retard, unstable A/F and idle bounce... get the MAF right first then fine tune elsewhere.