Hello all..
I was wondering if any of the top dogs here use, or can use a speed density system in place of the MAF on our GN's. I really don't want to use a MAF translator system, and would benefit from using the 749 ECM from the Typhoon/Syclones with Speed Density instead of a MAF. It seems the GN's MAF system is holding back a lot of potential from these motors, and my car (as probably ALL GN's) pin the MAF readings at 255 as soon as the car starts moving confusing the heck out of the ECM. Granted there are tables in the chips to add extra fuel when needed, but im not convinced a sloppy MAF system is really helping anybody here. A lot of the F-Body guys switch to the 749 ECM with some pretty incredible results..some gains on 500+HP motors are in the realm of 90hp MORE just by eliminating the MAF and using Speed Density to really fine-tune these suckers.
Any thoughts or info on this?
Jay
87GN
Wouldn't it be a lot easier to go with Ramchargers MAF And RPM range extender?
It's too bad no one pidked up on this subject. It could be an interesting discussion.
Keep us informed if you decide to do the swap.
Jay, a very strong proponent of the stock ECM is Bruce Plecan... he might be able to help.
I know the Sy/Ty guys struggle with resolution at higher boost levels (since they have to go to a 3 BAR MAP) and as such, sometimes have driveability issues.
He's got some very good input on how to use the stock ECM with the LS1 MAF and such.
Thanks Ken.
Bruce already replied about the issue, and I think i'll leave it at that. He's been there, done that, so I dont want to go messing around if the MAF is plenty for our cars. It was just a case of a little lightbulb going on in my head after seeing some guys doing that at the track. (POOF!) Lightbulb's out now..
Here's Bruce's reply in case anybody would like some more details on it - thanks for the help, Bruce! - :
"Speed Density has nothing to offer over a properly set up MAF system, ie,
If you were to go to a blow thru MAF, delete the screen, use a translator,
you can match or outdo any ecm out there, If your good at tuning and doing
your own chips.
The 749 doesn't *speak* DIS, if you want to figure out how to install a
reluctor type distributor, then it's a possibility. But then you have to
fight the *bug* in the 740 code.
Spend some quaity time really trying to grasp the power of the 148, and
you'd change your mind. It's a marvelous little ecm. But people tend to
condem it and make statements about it, without even researching what's
going on.
As it turns out the MAP system (s) are slower then the MAFs in response,
because the MAP sensor has soo much trash in the signal, it takes more
filtering to get useable info., from what I've heard from a reliable source.
The *issue* of the lag time in *hot wire's* react time also turns out to be
mute.
Bruce"
Hi all
I trans-planted my 86 turbo engine and trans to my 36 street-rod. It's basicly stock now,but i don't have a good place to mount the MAF and IAT.
I looked in the tech area at relocating the MAF to after turbo. It seems like what I would like to do,to keep things neat and clean.Any other idea's.
I'm guessing that Bruce has possibly changed his mind on this post?
You too Jay?
Yup - a lot of time has passed since that post was made, and Bruce is leading the pack (actually he's the lone ranger on this one), and the 749ECM has found a home in his car. After an ungodly amount of research and testing - it's working! Bruce asked the following to be reposted to this list - might be time for a new thread on the 749?
> I maybe spoke too quickly,
> I guess you could consider changing one minds,
> but, that's due to new data.
>
> Yes, cars can be made to run in the 9s with the oem MAF system, and from
the
> tuning I'd done with the MAF system in the past, I thought the MAF system
> was as good as things got.
>
> I've also been on a bit of a journey since that post.
> I would have never thought that I'd have a GM ecm running non-gm code. Or
> have totally rewritten MAF code, let alone change the system from MAF to
> MAP. These last two sentences represent several years of work, and yes,
in
> few years worth of work one, might change his mind.
>
> Bruce >