Pro Stock John

iTrader: (34)

I read about it being 571 grams/second can anyone elaborate on what happens and when?

XLR8NSS

iTrader: (4)

John the stock computer can deal with numbers up to 512g/s.(some sort binary computer voodoo limits that number <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> ) This equates to ~67lbs/min of airflow which with a good tune is ~670flywheel hp. This can be accomplished with a stock MAF that has been recal'd and the computer tweaked with LS1edit.

Above that if you want the fuel handled by the computer you either add it in the PE table(not the best way IMO), Rig up a super duper Harlot setup <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> , or go to a FAST system.

I think most stock MAF tables are setup to read 453g/s max. which equates to ~58lbs/min.

What happens if you go over the threshold too far?

I'd imagine <img border="0" alt="[bomb]" title="" src="graemlins/gr_bomb.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

JK

Pro Stock John

iTrader: (34)

Does it set a SES lite? Like the old PO103 code, the high frequency MAF code or something like that?

I have been told the values just stay the same and so the pcm will stop making changes... I guess the key issue is how dangerous that is.

XLR8NSS

iTrader: (4)

It probably will set a MAF high frequency code.

Once the computer stops reading extra airflow you should see the A/F ratio start to go lean. You can compensate by adding fuel in the PE vs. RPM section once you reach the limits of your MAF. The problem with that technique is that the computer won't compensate for weather and atmospheric conditions at that point.( I don't think)

Hopefully some people who have tuned this way will chime in with some info. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

John

MelloYellow

No real details here, but I think you can play with the stock MAF up to about 650rwhp. Past that and def over 700rwhp you need to think about some crazy fixes.

Black LS1 T/A

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong> Does it set a SES lite? Like the old PO103 code, the high frequency MAF code or something like that?

I have been told the values just stay the same and so the pcm will stop making changes... I guess the key issue is how dangerous that is. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Mine is over. No code.. I'm told the PCM just doesn't know what to do after that and your stuck with where things left off in some way. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

The RPM/PE table seems to still let fuel be added, though.

Mike Morgan

John,
First it depends on the year. I would recommend a '99 up PCM for S/C applications. A '98 PCM will work, but it is a bit trickier.

You will max the MAF at about 500 RWHP on a blower application. If you adjust the MAF limits in the PCM you can get up to about 560 RWHP.

I would be very careful with just changing the PE multiplier. It doesn't work like you'd think.

Lost & Found2

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Mike Morgan:
<strong> John,
First it depends on the year. I would recommend a '99 up PCM for S/C applications. A '98 PCM will work, but it is a bit trickier.

You will max the MAF at about 500 RWHP on a blower application. If you adjust the MAF limits in the PCM you can get up to about 560 RWHP.

I would be very careful with just changing the PE multiplier. It doesn't work like you'd think. </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Mike,
Not to get off the subject, but i was told by your shop that I had to run a MAFT at a ** rate due to maxing out my MAF. I found this a little hard to believe, but I'm not a pro by any means.

What is the best way to correct a maxed out MAF on an FI setup running over 600RWHP?

This is Jay Krites, we've talked about my ATI 383 setup a fair amount.

Thanks for your help and time <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

smokinHawk

iTrader: (48)

How come nitrous users dont seem to worry about this? Alot of them push over 600rwhp with a large shot with built engine, and i dont recall any of them worrying about maxing out there MAF frequency?
Or did i miss it?

slow

iTrader: (7)

you really dont see "dry" nitrous users with that kind of power.

The wet kits dont spray the N20/fuel through the MAF, so its not a real concern.

Ryan.

Pro Stock John

iTrader: (34)

Thanks for the responses, I did not see exactly what I wanted but I'll piece together a scenario, tell me if this makes sense...

Let's say that at 500rwhp my MAF maxes out... Well hypothetically in my planned 700rwhp project I would think that I would hit 500rwhp by 5000 rpms (maybe a little later like 5500 rpms?), so then from 5000 to 7200 rpms where I plan to shift my car the MAF is pegged out so the pcm will no longer make any more corrections to the AF beyond what it was doing at 5000 rpms right? I just want to see if I understand that.

What about a 99 plus setup, it maxes at a higher rpm?

MIGHTYMOUSE

iTrader: (59)

tuning the pe table has become a real pita.. from 30* outside to 60* outside i go from just right to waaay rich.. i gotta take out the automatic adjustment for temperature or amplify it or something..

mine is a 98 so after 11250hz the computer stops reading the maf, it doesnt matter what g/sec you assign to it. with the new turbo im peaking out on atap around 12,200hz which would be somewhere around 500g/s if it would read it.

mine happens to be at 370g/sec per stock 01 ls6 maf which really sucks.. planning on going back to a stock maf really soon to at least meter up to 450.

XLR8NSS

iTrader: (4)

John your right about your theoretical situation and MIGHTYMOUSE has found one of the limitations to tuning with the PE table. It doesn't account for the extra O2 in 30 degree air compared to warmer air. So you tune for 30 degree air to be safe when it's cold out and then when it gets warm all the sudden the tune is rich because there is not as much O2 in the air.

I imagine barometric pressure could cause similiar problems.

Headache time. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

John

<small>[ March 11, 2003, 10:50 AM: Message edited by: XLR8NSS ]</small>

CHRISPY

You know what you could do <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />
Tune the car to the limit of the MAF. (Whatever RWHP that turns out to be)

Then throw a wet kit on and spray to your RWHP target using the fuel from the wet kit to acheive the proper AF at WOT <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

LOL!
Chris

Guido

lol @ chris! That is about as bad as putting an FMU on! ahah <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

John, how come you cant convert to a FAST system? That would make life much simpler and you've got plenty of tuners at your disposal in your area.

Good luck! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

CHRISPY

he can he is just being ornery <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Lost & Found2

A FAST system cost $2500 as well. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
There has to be some other options? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

Noyzee

iTrader: (37)

I know East Side Performance is running over 700 on a MAF car, it is with N2O but it is over 700, 9 sec pass!!! Tuned by NoGo
NoGo tuned my turbo car and gave me a flat lined AF, very good tunner <img border="0" alt="[worship]" title="" src="graemlins/gr_hail.gif" />

Pro Stock John

iTrader: (34)

Noyz that is not the same since it's not relying on the MAF to help with fuel enrichment.

Well, it comes down to this, if the MAF pegs out at like 550rwhp in that neighbourhood, then we need an aftermarket system.

I am talking to a company about another system, it's too early to tell if it addresses all of our needs but it's specific for the LS1 so it would elminate the need for any adaptor boxes. I'll know in the next 1-2 weeks if I can get a box for us to evaluate.

Worst case I will do FAST but I think this other option might be more effiecient and also cheaper.

PSJ
LS1Tech R&D

MIGHTYMOUSE

iTrader: (59)

you can definitely get the tune right with a stock style maf setup, you just have to do it yourself in edit instead of letting the maf calculate it for you.


you can get a 'harlan' setup from pro-m for about 700 bux.. from there all you need is to know how to use ls1 edit and you are golden.

that is the only 'cure' at the moment other than aftermarket computer..

after all, the problem is in the computer, not in the stock maf. you just have to build a maf that lies to the stock computer by a predictable amount that you can reverse engineer into the computer.

i would not consider going to an aftermarket computer system 'budget' oriented if that is still your goal.