turbo

iTrader: (10)

What do we do when we have to much hp? Can we run duel maf or go speed density?

Was just curious, heard all this stuff about maxing out the MAF so what do people do.

Thanks

Casey

strife

The Callaway modified C4B LS1 in Oz runs speed density setup using the factory pcm.

A few of the local tuners here are on to it as well

Colonel

Run larger injectors and lean the mixture back out by lowering the reported load with a MAFT.

Or, if you want expensive go with a DFI setup.

turbo

iTrader: (10)

Strife, thats what I wanted to know. Ive ran the car on speed density, of course just at idle. But I know theres a way to do it if you mess with it.

Colonel, how does that work exactly? Is it effiecent only to a certain level or no? Also where can I read up on the DFI setup?

Thanks a lot!

Casey

<small>[ November 17, 2002, 09:08 AM: Message edited by: turbo ]</small>

Colonel

Say you have stock 26.4 lb injectors and you have just barely maxed the MAF sensor out at 54 lb/hr (been awhile but I think this is the max.) Now, you install 36 lb injectors. Your Ltrims go WAAAAAAAY up. That means you're way too rich with the larger injectors. So, you lean (this means lowering the reported load from the MAF) the Ltrims back to zero with a MAFT. Now if you check you MAF sensor it should be reporting about 39.6 lb/hr. One side effect doing this is higher timing advance. If you had 27 degrees max before you might have 30 degrees afterwards for example.

I've used this method with 51 lb injectors too. That really gives you alot of room to play with.

Don't know of where to read up on DFI. I'm sure someone here does though. JS?

<small>[ November 17, 2002, 04:06 PM: Message edited by: Colonel ]</small>

turbo

iTrader: (10)

Thanks Colonel! Going to start building a motor soon and ive been away for almost a year havent been caught up lately.

Casey

Colonel

I should point out that I don't know if a MAFT has enough adjustment to make tuning in 51 lb injectors possible (these were Lucas 42.5 lb injectors which are actually about 51 lbs at the LS1's 58 psi.) I did it with a MAFT, a ported MAF sensor (further lowering the reported load) and computer tuning. I think it would have been just a little out of the MAFT's range of adjustment if not for the tuning and ported MAF.

turbo

iTrader: (10)

lol Thanks Colonel, your an encyclopedia of LS1 knowledge. <img border="0" alt="[hail]" title="" src="graemlins/gr_hail.gif" />

Most likely be talking to you more when I start building my engine.

Thanks again

Casey

y2khawk

iTrader: (5)

Don't try for speed density with boost <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

1 BAR map sensor + stock PCM in SD = many melted pistons.

Just FYI.

turbo

iTrader: (10)

Thanks Harlan, do you use the same method as Colonel?

Casey

HOWQUICK

for what it is worth....we are seeing upto 15 extra rwhp by eliminating the maf. If you are seeing the map 99kPa with the maf on....you are missing some power.

All mafless- speed density programming via the Delphi PCM....no need to replace it....just TUNE it... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

jmX

Harlan, you were using an aftermarket maf (Pro-M?) for your car right? How did that turnout?

GeorgeC

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by HOWQUICK:
<strong>for what it is worth....we are seeing upto 15 extra rwhp by eliminating the maf. If you are seeing the map 99kPa with the maf on....you are missing some power.

All mafless- speed density programming via the Delphi PCM....no need to replace it....just TUNE it... <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Now that sounds interesting, as I've pondered a switch to SD mode with the stock PCM myself.

Where would you start? The VE tables don't make much sense to me. Any tips you can offer if one was to try this??? <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

turbo

iTrader: (10)

Where can I read up on this delphi pcm and where to buy it, sounds interesting.

Casey

y2khawk

iTrader: (5)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by jmX:
<strong>Harlan, you were using an aftermarket maf (Pro-M?) for your car right? How did that turnout?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I still am. It's working VERY well so far. I was maxing the stocker at 10psi on pump gas, with 132 traps. hitting 12kHz and over with that setup.

Swapped in the Pro-M w/ VtoF converter and dropped in the appropriate changes to deal w/ the BIG airflow numebrs. I'm now able to turn it up much farther and still deliver fuel. I barely see 10 kHz w/ the new setup, and I'm running 143 traps. So, it's working. A/F is solid w/ the MAF and 96# injectors w/ driver box. Just took some time tweaking everything to get there.

BTW, the "delphi PCM" is the stock PCM. It's made by delphi

GeorgeC

Stock MAF (screen removed), stock ported TB. Car weighs ~3100lbs or so (3130 last time I weighed it, but have lost a couple lbs. here and there).