I have a b18c block bored 81.5mm. Ls crank, ls eagle rods and wiseco 9.5:1 pistons. b16 head, stock valve train and cams. gt3076 turbo, gm 3 bar map and using crome. 200 compression across.

I've gotten it to idle and run the best using a p30 basemap and making changes (map, boost columns, injector sizing and offset, fuel and timing compensation for boost).

I would like to hear a few suggestions on how to make it idle fairly smooth. I'm having a little bit of a rough idle, and my wideband is reading between 17.9 - 14.9 at idle(1000). Also any suggestions as far as timing and fuel tables.

Thank you.

 

What are your injector/fuel multiplier settings?

Did you set up your injector offset, battery offset and final multiplier using fuel tools before you made any changes in the fuel/ignition maps?

 

I changed the injector size, multiplier and battery offset first.

 

What ROM base are you using, P28, P30 or P72?

If you are using the P30 JDM, P30G EDM or P72 you can add fuel tools to your ROM. You will then have an advanced tab under your multiplier calculator tool.



Under that tab it will allow you to make a few more individual fuel corrections. There is a box for making additional offset adjustments. That is one of the things that I usually use to help dial in my idle AFR and RPM.

 

I just installed it under the p30. What kind of scale should the adjustments be made on? As in what numerically would I enter in a given box, and how would that affect my afr?

 

IIRC the offset units are in milliseconds (ms). I usually start with an offset around 20.0 and move up or down in increments of 5-10 until I notice the engine idle starts to smooth out.

Check this tutorial out; Adjusting for Injector Size Half way down the page it talks about setting up for larger injectors and getting your car to idle properly using the fuel multiplier before playing with the fuel maps.

 

Thanks man, you've been a big help.

 

Not a problem!

Good luck

 

Something that may help after you get your multipliers dialed in etc:

Change the ignition timing on the low cam table to 18 from 500-1000 rpms from 119-518 mbar

 

Okay cool, thanks. Now with the multipliers being set at 1 stock. Wouldn't that mean they would need to be around .25 with 1000cc injectors if stock injectors are 240cc?

 

LOL, this way going to be my exact recommendation also...