I usually get my base tune done by Madz28, but if at all possible i'd like to do this myself.

I'm completely maxing out my MAF by 5K rpm (471g) so i need to switch to speed density or get a new maf. I'd like to go SD, is there a way to change my tune file myself, or is there some things that need changing that requires more then just changing some settings in tunercat?

 

I think you have to disable the O2's and MAF first. Install a 2 bar sensor, half the injector constant, then take a SWAG at all the MAP-affected tables and constants.

Let me know how it works because I'd like to try it also.

 

Why disable the O2s? They still provide feedback in SD mode.
I'm running speed density mode (1bar, 5psi) but had no chance to tune much before my car went into stasis for the winter. I'm also interested in hearing some more thoughts/experiences on using a 2bar MAP, as I know you are Mike...

 

I believe it would be easier to get the VE table right if you didn't have O2 corrections affecting the actual A/F ratio all the time.

Mike

 

From what I understand, it's not that easy to switch to a 2-bar MAP. I honestly haven't heard of anyone that has successfully done it. Tuning in SD is pretty easy. Instead of making fuel corrections in your MAF calibration tables, you'll make them in the VE tables. Add to the numbers and it'll feed it more fuel; lower the number and it'll take fuel away. Just log the car and find out where it's wanting to run lean or rich, then make the appropriate changes.

 

Yes, I know. I was being a little sarcastic.

Alvin at PCMForLess did a '93 one time, but said it was a real pain and doesn't recommend anyone else try it. I'm going to give it a try eventually and if it doesn't work, switch to MS2 for fuel-only.

Mike

 

use ve-master

 

It's very easy to switch to SD mode and tunercat can do it.

 

Thats nice, now how do you do it?

 

Supposedly there is a toggle switch to go to SD mode. However, I couldn't find it, so I unplugged the MAF and turned off the MAF Error Code. It automatically defaults to SD if the MAF is unhooked.

Mike

 

And that lets you adjust WOT via the VE tables? Your sure? I don't want it to lean out when i'm running 6K rpms and 8 psi of boost.

 

Well. . . yes. You can adjust WOT on the VE table and also the PE table. I wouldn't jump straight to SD mode at 6k rpm and 8 psi, though, without lots of tuning, playing, and very short full throttle bursts. Also, with the 1 bar MAP sensor and 1 bar tune, it won't see boost. If you try SD mode with the 1 bar, it most certainly will run lean. It will give no additional fuel beyone 0 psi boost.

Mike

 

I know that you need a 2 or 3 bar map if you have FI and doing the SD mode.

I've got a wideband 02 on the car to help with tuning.

 

in the constants table just check the box that says speed density mode. Then work with the ve tables.

 

is the restriction the pcm, since it doesnt understand anything over 100kpa?
wonder how the voltage works on a 2bar map compared to a stock