Speed Density FAQ

Freon · **Posted:** Thu Jun 12, 2008 8:43 pm

I guess it would probably be better to branch off any specific tuning on a particular car (i.e. log analysis) and leave this for general SD questions. If you think something is a peculiarity with SD itself it probably should end up here at some point.

Justin 05 STi · **Joined:** Thu Mar 02, 2006 2:51 am **Posts:** 345

Is there anything I can do to help create an 11J SD rom for '05s?

caveat: I'm not a programmer by trade. :oops:

racedynamix · **Posted:** Sat Jun 14, 2008 5:43 am

Freon wrote:

Well, I plan on doing that myself as time allows, but knock yourself out. I released source code and modeling so it could be understood but also to be reproduced.

I will probably not be able to get to them all. I'm mainly shooting for 04-07 STI and 06-07 WRX, and eventually 08 as well. It may be a while before I get around to all the LGT and FXT models.

I know things are slightly rearranged in some ROMs. Like the D/A conversion will happen in one subroutine, then another will check the upper and lower CEL limits (for P0102 and P0103). You may be able to place the code in either subroutine. I haven't quite gotten there yet.

I didn't mean to come off as overly defensive.

Will this include the A8DH200Z ecu from the EU 07 STi ?

Desperate for a SD ecu for my car as hitting 400 g/s now on current set up.

Freon · **Posted:** Sat Jun 14, 2008 4:36 pm

It's unlikely I will add wide support. Sorry, I just don't have the hours to put into it. Just a few US STI and WRX models.

tjamz · **Posted:** Fri Jun 20, 2008 7:34 pm

Freon wrote:

It's unlikely I will add wide support. Sorry, I just don't have the hours to put into it. Just a few US STI and WRX models.

By US WRX models, I hope that the MY02 WRX model is included in that list...or that someone else will create a rom that utilizes speed density in some way.

wittmer25 · **Posted:** Sun Jun 22, 2008 6:38 pm

So just a question, would UTEC still work as a piggy back controller with SD? Would you have to tune the UTEC in SD mode or MAF mode? Just curious.

Freon · **Posted:** Sun Jun 22, 2008 6:53 pm

If your MAF was still hooked up correctly you could run the SD reflash and a UTEC on top running SD or MAF, it wouldn't matter. I don't know why you would do that, though.

wittmer25 · **Posted:** Sun Jun 22, 2008 7:21 pm

I was thinking about running multiple maps; one for meth and one for 93 oct. Not a good idea?

Freon · **Posted:** Sun Jun 22, 2008 7:33 pm

I hadn't thought of using SD UTEC on top of SD, but go for it. Nothing wrong with that.

fastblueufo · **Posted:** Mon Jun 23, 2008 10:29 am

Freon, on your sd spread sheet in -8 and -12 columns and 800 and 1200 rpm rows I'm getting numbers I don't think are right. For example, if I put 4.9g/s it gives me a ve# of 1.?. Shouldn't the ve be below 1 like .6? It works great on the rest of the rows and columns.

ride5000 · **Joined:** Thu Aug 03, 2006 2:40 pm **Posts:** 1934

fastblueufo wrote:

Freon, on your sd spread sheet in -8 and -12 columns and 800 and 1200 rpm rows I'm getting numbers I don't think are right. For example, if I put 4.9g/s it gives me a ve# of 1.?. Shouldn't the ve be below 1 like .6? It works great on the rest of the rows and columns.

ve can (and will in my experience) go above 1 at certain rpm ranges.

fastblueufo · **Posted:** Mon Jun 23, 2008 1:03 pm

Yes it will go over 1. But if this sd rom calculates ve like I think it does then if I have a ve of over 1 at or around idle I will be extremely rich in that area. I shouldn't have the same ve at idle as I do at peak tq.

Freon · **Posted:** Mon Jun 23, 2008 10:35 pm

I posted my VE map. I think you might go over 100% slightly in midrange where the engine is the most efficient. At least all the math works out to indicate that. I think my current maps goes up to 0.99 or so.

This is nothing that you couldn't also derive on a MAF system. It's no different. The VE map is not an actual measured VE, it is what you program it to run.

ride5000 · **Joined:** Thu Aug 03, 2006 2:40 pm **Posts:** 1934

fastblueufo wrote:

Yes it will go over 1. But if this sd rom calculates ve like I think it does then if I have a ve of over 1 at or around idle I will be extremely rich in that area. I shouldn't have the same ve at idle as I do at peak tq.

basically, injector scaling will shift the entirety of the VE map up or down.

fastblueufo · **Posted:** Tue Jun 24, 2008 12:07 pm

I realize that scaling will move the map up or down. If you look at the map in 3d graph it should slope upward to max tq and then taper back down a little to redline. I have a high spot around idle. A really high spot! It seems that the spread sheet is calculating wrong ve# in the idle area of the map. I'm about to try the sd rom. I will post my input when I am through tuning. Can't wait to see how well it works.

RomRaider

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