XFI Going from 83's to 160's

[lazaris]

Beside changing the injector flow rate size can you just highlight the whole VE and subtract say 93% to get you close for the increase in injector size?

 

[Chevota]

Just change the flow rate of the inj from 83 to 160 and see where you're at. I didn't have to change the VE table on mine much to get it back in line.

Scott Wile

 

[S2V6RACER]

All your injector pulse width tables will be off also.

Will take some tuning to get all of your cold start/cranking/idle VE and WOT stuff back in order.

 

[lazaris]

Just change the flow rate of the inj from 83 to 160 and see where you're at. I didn't have to change the VE table on mine much to get it back in line.

Scott Wile

I would think the VE tables would now be very high for the 160's. Are you saying that just changing the flow rate will make the VE table fall in line with the increase?

 

[Mike E]

I would think the VE tables would now be very high for the 160's. Are you saying that just changing the flow rate will make the VE table fall in line with the increase?

Ask yourself this. Is your VE (volumetric effeciency) changing becuase you are changing injectors? Negative. As long as everything was right with the 83's, the VE table shouldn't have to change with the 160's. Any table that give a pulse with output will have to be adjusted though.

 

[Dusty Bradford]

Change the injector size to 160

Go to cranking fuel table which is in milliseconds, highlight the whole table and lower it in half. If you have 6.0 in the middle of the table, lower it to 3.0.

This will get it close, some of the VE #'s may have to be moved a little and of course cranking and afterstart may need adjusted. If the car cranked great before, those two adjustments will be very close.

 

[lazaris]

Scott, Mike and Dusty thank you. I'll give it a try.

 

[lazaris]

After trying the suggestions the VE map is way off from the 83's. Does anyone have a 160 file to try?

 

[Dusty Bradford]

Is it rich or lean?

14 volt system?

What's the injector opening time?

 

[callmeebryan]

Interesting.... your VE shouldnt have to change much at all. The FAST takes in to account your injector size and uses VE in an equation to calculate how much fuel is injected. Is it not running well in a cold start situation? You may have to mess with all those settings like people have said before.

Worst comes to worst, why not run it in closed loop, set your target AFR, and then look at the O2 correction and make the nessesary changes? FAST makes this very easy to do.

 

[lazaris]

Its rich cruising. 14v. Injector opeing time is .7
Cold start I have down pretty good as well as cranking and AE fuel.

"The FAST takes in to account your injector size and uses VE in an equation to calculate how much fuel is injected. Is it not running well in a cold start situation?"

I think it calculates how much fuel yes, but I dont think it compensates the amount injected basied on the inj size and the prior VE tables you had for 83's ? At leaset it doesnt appear to.

 

[callmeebryan]

Its rich cruising. 14v. Injector opeing time is .7
Cold start I have down pretty good as well as cranking and AE fuel.

"The FAST takes in to account your injector size and uses VE in an equation to calculate how much fuel is injected. Is it not running well in a cold start situation?"

I think it calculates how much fuel yes, but I dont think it compensates the amount injected basied on the inj size and the prior VE tables you had for 83's ? At leaset it doesnt appear to.

Well according to the manual, you are tuning your VE tables to your engines actual VE, according to how you set up the FAST. I can see why doubling the injector size may cause a problem, but it shouldnt be difficult to tweak the maps a little bit to put everything back in order.

:redface:

 

[Blazer406]

Its rich cruising. 14v. Injector opeing time is .7
Cold start I have down pretty good as well as cranking and AE fuel.

"The FAST takes in to account your injector size and uses VE in an equation to calculate how much fuel is injected. Is it not running well in a cold start situation?"

I think it calculates how much fuel yes, but I dont think it compensates the amount injected basied on the inj size and the prior VE tables you had for 83's ? At leaset it doesnt appear to.

You may have to lean out the VE cells for the cruising portion of the map... as well as play with the closed loop correction limits... so the ECM can't add or take away too much fuel....

 

[lazaris]

Yes it appears I will have to work on the VE tables for cruise and probably the rest of the VE map. Reading the manual it basically says you wont have to change the VE tables either when going to the larger inj's. just the inj size.
Mine however isnt showing that.

 

[lazaris]

Does anyone have a 160lb .gct file to try?