2 Questions for you guys with Accel DFI.

[V6UnderPressure]

1. Does anyone have a program that will work with my combo (see my profile) so I can get it to the tuner and can you send it to me via email. He wants it installed first. 2. Does accel dfi work better with the MAT sensor at the up-pipe like the others do? Thanks!

Scott

 

[V6UnderPressure]

TTT, anyone out there running accell dfi besides me

Scott

 

[NEVERLIFT]

Scott

Sent You E-mail

 

[TurboJim]

A speed density calculation needs air temp in the engine. The best place for the sensor is in the plenum. You will have the most accurate calculation. If it it put in the up pipe, it will work, but not as accurately. Think about it. If the ECU doest its fuel calc based on 70* air, and the air is 120* the calc will be off (as the ECU fuels for more dense air) The amount may be negligable, and you can tune around it, but in any event, it wont be accurate.

Just food for thought....

 

[V6UnderPressure]

Jim, I agree to you to an extent. However I am going to throw my 2 cents in with the up pipe(closest to plenum) vs. the Plenum itself. I dont see how there could be that noticable of a difference versus the top of the up pipe and the plenum. Air does not cool or heat at a split second. And the speed of air flow between the top of the up pipe and the plenum is pretty quick, especially when under boost conditions. In that time, I dont see how the air could change temp THAT fast. Maybe .0000001 degrees change from up-pipe to plenum but thats all I see in my opinion. Take Ice for instance, if you put it in the sun it slowly melts. It doesnt turn to water in a split second. This goes the same for water freezing and the temperature outside. While it can drop pretty quick it usually drops 1 degree at a time. I don't see there being any difference between up-pipe and plenum. But throw in any info if ya can! Just wanted to voice my opinion. Plus getting the MAT sensor in the up pipe is a lot easier than in the plenum. Again Just my 2¢.

Scott

 

[bruce]

Originally posted by Scott4DMny
Jim, I agree to you to an extent. However I am going to throw my 2 cents in with the up pipe(closest to plenum) vs. the Plenum itself. I dont see how there could be that noticable of a difference versus the top of the up pipe and the plenum. Air does not cool or heat at a split secondScott

Hey, easy enough to figure it out, do both locations and actually see.

BTW, there is a difference.
At the lower flows, the air is relatively slow moving thur the plenum and picks up alot of heat.

If you want the best performance possible, you want the ecm making it's decisions on the air entering the combustion chamber, ie get the info as close to the intake valve as possible.

And for split second heating of the air, figure out how much time the air spends in the turbo, and how hot it gets at WOT. Hint, it ain't very long.

 

[V6UnderPressure]

Originally posted by bruce
And for split second heating of the air, figure out how much time the air spends in the turbo, and how hot it gets at WOT. Hint, it ain't very long.

True bruce but we are not talking about between the turbo and intake. We are talking between the up pipe and intake. Besides turbo is not a variable as you have the intercooler between it. And even at idle the air is not moving THAT slow. I would like to put two holes and see, but I've done enough drilling/welding on this thing!

 

[V6UnderPressure]

Just wanted to make sure someone clearly answered my question. With the Accel DFI that I have which uses calmap 6.32, is the mat better in the up pipe/throttle body? Just wanted to make sure.

Scott

 

[TurboJim]

I thought Bruce and I BOTH told you basically, as close to the cyl as possible is what you want. If you dont want to do that, do whatever makes you happy

 

[JDEstill]

I wouldn't worry about it, put it in the uppipe and forget about it. Especially since I don't think your DFI is a true speed density system anyway. It is basically just taking the rpm and MAP and looking up a pulsewidth. There is an air temperature correction, % enrichment vs. air temperature, so you can make it act like a speed density system, but it seems like a fair of amount of work to get that dialed in, and I kinda figured most people don't bother, though I could be wrong. If that table is zeroed out in your program, then it won't really matter where you put it!

That table doesn't look like it is set up that great, it looks like it can only add fuel and not take it out. To set it up right you'd have to pick a baseline temperature that's relatively hot, like 150F, and all of your baseline pulsewidths would be based on that. Then you can figure out the amount of enrichment you need for temperatures colder than that, and put that in the table. That's easy enough to do, it's a pretty simple calculation. Still not the way I'd do it if I was designing the system from scratch... in which case I'd do it like the FAST does it!

John

 

[V6UnderPressure]

Thanks Jim, I know you told me WHERE to put it, but I wanted to make sure that the ACCEL DFI Program uses the speed density therefore making sure that I dont waste my time putting it up there. No one clearly answered that. I guess it wouldnt hurt. Thanks.

Scott