Fuel Injector Mapping

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Raybrant
 

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Joined: Fri Aug 07, 2015 2:12 am

Fuel Injector Mapping

Post by Raybrant »

Sorry for this newbie question but we all have to start somewhere right? I've already read through the 3 main pdfs and couldn't find a straight answer.

Car is a '90 GTS-t with an RB20, Nistune is on a matching RB20 ECU. Have a couple of modifications but for purposes of the tune, it's only has new Injector Dynamics 725cc's. To start my tune off I just took the stock map and did the automatic injector rescaling while ticking all 3 boxes (load max, cranking tables, TIM/TID). From stock 270cc's to 725cc's brought the TIM from 512 to 190. Starting the car like this made it run very lean around 16-20 and it would knock. I adjusted the TIM to 290 to get it to stoichiometric with the short and long term fueling very close to 0.

Is it normal to see only a moderate drop in TIM with injectors almost 3x as big?

My AFRs also jump around a lot since going to these injectors with a +/- 0.5 while my stock ones only had at most a +/- 0.2. I gave ID a call and they said a range of 1.0 is not terrible or uncommon. Just want to hear it from another mouth that confirms this. Latency values were grabbed from their website.
Last edited by Raybrant on Sat Sep 19, 2015 3:02 am, edited 3 times in total.
Matt
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Re: Fuel Injector Mapping

Post by Matt »

So far so good. Automatic calculations do not take into consideration other factors like fuel pressure, so an increase was needed in TIM (not TID) parameter

You can try increasing latency to improve idle, and this may need TIM lowered a little afterwards

I think about +/- 0.5 seems okay, but you might be able to narrow this a little using the latency
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