Mike Morgan

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Lost & Found2:
<strong> 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" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hey Jay,
A translator is a simple way to scale the MAF to change the frequency input. I then go into the PCM and make similar adjustments. This works well for about 650 RWHP, beyond that I get a lot more creative inside the PCM. I have to; I have 1 427 D1 Car I'm wrapping up right now and have 4 more waiting in the wings <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

I'm not worried about the stock PCM limits, I can get around a lot of it. I wouldn't recommend an aftermarket system unless that was your only option and you don't have a tuner available or don't want the car shipped to a tuner such as myself(shamelesss plug <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> )

Any updates on your fuel pressure situation?

Black LS1 T/A

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">I was logging upwards of 13 parameters, so I don't have many data points on these example logs.
I plan to lower the parameters to: RPMs, MPH, KR, O2, IPW... I'll know my timing from KR.

I'm also having trouble getting LTFT's down since I put the 55#'ers in... still working on it.

4.10 Pulley (2 to 3 PSI peaking at 4 to 5 PSI)
RPMs MPH Timing KR O2-B1 LTFT MAFppm MAFgps MAFfreq IPW1

1154 6 17.5 0.0 95 21.9 19.761 150.38 7859.4 13.11
3500 19 24.5 0.0 930 21.9 42.039 319.91 9825.2 15.96
5446 37 21.0 0.0 935 21.9 62.712 477.23 10966.3 18.02
6602 44 18.0 3.2 920 21.9 67.280 511.99 11190.4 18.97

I got the LTFT's down some and banged the rev limit on this one when it hit.
I also leaned it out some, but I didn't intend for it to go to 7-grand RPMs,
and O2 dropped so low due t fuel cutting off

RPMs MPH Timing KR O2-B1 LTFT MAFppm MAFgps MAFfreq IPW1

2421 7 20.5 0.1 900 10.2 31.753 241.64 9044.4 14.11
3978 25 20.0 0.0 910 10.2 61.707 469.58 11027.8 16.24
6084 41 20.0 0.0 915 10.2 67.280 511.99 11552.2 15.63
7139 46 18.5 1.2 875 10.2 67.280 511.99 11697.3 17.58
6522 60 19.0 1.5 915 10.2 67.280 511.99 11372.6 16.48

Here, I just went back to the 3.20 pulley (4 to 5 PSI peaking at 7 to 8 PSI) today.
It spun so much (yes, I DO have the M/t ET Streets on) that I have even FEWER data points,
even though it went thru 1st and halfway thru 2nd gear

RPMs MPH Timing KR O2-B1 LTFT MAFppm MAFgps MAFfreq IPW1

1529 15 24.5 1.1 870 11.7 39.341 299.38 9704.1 16.02
4691 31 20.5 1.2 905 11.7 67.280 511.99 11697.3 16.95
6670 44 20.5 1.5 925 11.7 67.280 511.99 11680.2 17.30
5560 66 20.0 1.4 910 11.7 67.280 511.99 11505.9 17.78
5547 67 20.5 1.3 905 11.7 67.280 511.99 11523.9 17.62

This is on pump gas.

First, I need to get my LTFT's as low and consistent a possible.

Then, I'm going to monitor RPMs, MPH, KR, O2, IPW for most data
and try to see what I can get out of it before my Fuel pressure starts to drop.

I want to keep O2's constant without max'ing out the injectors, Less than 2 degrees KR
and a reasonable Injector Duty Cycle. After I get something worked ot, I'll visit the
dyno again for fine-tuning the A/F ratio. But, I know I will run leaner on the street
than what I did on the dyno.

Maybe some of those logs will help see what MAY be happening...
... I need more datapoints to be sure.</pre><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">

SS00Blue

</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>A translator is a simple way to scale the MAF to change the frequency input. I then go into the PCM and make similar adjustments.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">How do you set up the translator for this? Perhaps, just dial up full lean percentage on the WOT switch? Then just turn up the wick (read: boost) until the magic 512g/s shows up again?

SC-

<small>[ March 12, 2003, 06:17 AM: Message edited by: SS00Blue ]</small>

White_Hawk

iTrader: (3)

There are two problems when you max out the MAF. One is when the frequency goes too high the ECM can freak out a little (mine would feel like I hit a rev limiter). The second is that it won't read true airflow.

The translator will fix both problems. It will fix the high frequency because it has a built in frequency limiter. Locking the frequency at WOT won't hurt you that much because you are running off the PE tables. Second, you can also rescale by lowering the frequency 15% with the MAFT and then adjusting the MAF table in the ECM by the corresponding amount. The only drawback to this is that it may effect your timing, since timing is referenced as a function of mass flow and load.

I think I am going to get one and set it at zero just to get the frequency locked at WOT and make tuning easier.

-Geoff

MIGHTYMOUSE

iTrader: (59)

white hawk, i do not run a translator and have never had inconsistent flatlining .. it just goes up to max g/sec and stops there..

the maf translator will get you in the neighborhood of 15% more, but you will have to start from scratch on building a new maf scale in edit. unless you flow the maf and record the new frequencies with the translator in place.

pro m also sells a gm frequency extender through granitelli.

i dont consider these bandaids as appropriate options for forced induction. especially when it throws off the whole curve for only a 15% gain.

Pro Stock John

iTrader: (34)

I talked to Matt Harlan and subsequently Greg Banesh and that custom MAF solution was priced at $900 two months ago has there been a change for that?

I consider a budget ecm solution to be anything at or under $1500. Keep in mind that FAST, DFI gen7, and potentially this other box can all utilize a wideband for on the fly corrections...

Let's look at one aspect of FAST to put things in perspective... You input your target AF ratio. FAST can correct up to 24% based on the wideband readings. Sounds pretty nice to me. The cost is out of control though, it's like maybe almost $3000 for everything and I have yet to find anyone using the Cartek adaptor box AND the EDist box together. I'd rather not spend $2500 for FAST to have it only control fuel.

That being said, Mike Morgan's comments are interesting to me but I think I will just plan on installing an aftermarket box above 650rwhp.

So we have to ask ourselves, the folks who dynoed around 700rwhp, did their cars run appropriate mph for the power? I think that 140mph or more is right for 700rwhp and a 3500 lb car what do you guys think? Raymer went 139mph I think but I wonder if his car was leaning out on the top end it was lifting heads or something on some of the fastest runs. Speed Inc. car went 128mph with less than 700rwhp but with a slipping 6 rib blower belt... Harlan went 143mph and did 700rwhp on an Eddy current dyno sounds good to me, he was more like 730-740rwhp on a Dynojet.

My plan at this time will be to get the car running NA, and then stage II will be to install the YS trim and intercooler, and the bigger injectors, and then an ecm solution.

I also want to run 110-116 leaded gas so that's another reason I want to go with an aftermarket box.

This new box seems to have provisions to add a map sensor so that means I could potentially ditch the MAF.

Cmarsh93z

My view is...that if you are pushing more than 600rwhp, why chance it with a stock computer? Most people have spent CRAZY money on their cars....yet they get all tight whenever it comes to engine managment? I think thats one of the most important aspects of the car when it comes to making it run good, and safe. 600+ rwhp on PUMP GAS requires no margine for error....are ya'll comfortable chancing your nice built motors? I for one am going to use Gen 7 on my T-88 Ls1....its just too easy.

Chris
AMS

CHRISPY

I agree with Chris on this completely. If you are pushing that much power, tune it the best way possible <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Chris

Pro Stock John

iTrader: (34)

I don't know if Rob Raymer is using an EDist box but his FAST is up and running.

Here's how I break it down...

Max out MAF: Need something like FAST, or custom MAF, or perhaps use the Translator for a bit more room
Low imped. injectors: Need something like FAST with low impedance drivers, or a converter box for $300.
Leaded gas: FAST does not use the stock 02's anymore.
Tables up to 7500: FAST has tables to what, 8000?

Cmarsh, do you folks have pricing on the DFI gen7, and how do you react when some folks say that the FAST works better and that some folks go faster by swapping from DFI to FAST? I can't see why but I have heard folks say that. Do you have gen7 running on an LS1 and if so what are you using for the crank trigger?

Black LS1 T/A

Just a question...

How come I was able to adjust the A/F ratio for a target amount consistently on the dyno, even though my MAF was max'd out (until I ran out of fuel)?

Why come being able to get A/F ratio dialed in with the PE/RPM tables is not enough, even IF certain "unspoken things" aren't able to be calculated by the PCM above max MAF frequency? It appears to ME that something was calculated well enough that I could adjust the A/F in spite of the MAF max'ing out.

I was able to make A/F run at 11.2, 11.4 from peak torque and rising toward 12.1:1 at about 6200 RPMs.

I don't know the answer, I'm just asking because I want to understand.

Thanks!

MIGHTYMOUSE

iTrader: (59)

blackls1ta.

doing it the way you did for a specific instance will work no problem.. thats what i did..

its when you change the boost level or change the air temperature and the computer doesnt adjust the fueling appropriately that people begin to sweat it. soon as i get the pe vs. temperature straightened out, then all i have to worry about is covering for all boost ranges, or upping the overall percentage whenever i up the boost.

i wont have any problem working it out because it is definitely possible to get repeatable and correct results using the pe table to any hp level. you just have to stay on top of your temperature and boost corrections.

Black LS1 T/A

Now, I find THAT to be true. Temp changes make a differenct, and of course, boost levels. I'll just have to try to stay on top of where my tune is at.

Right now, my big problem is getting fuel to the motor. I just started my new job and haven't had a check for a while, so I can't take the plunge for the Racetronics unit just yet. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

Blkknight

Maybe if we're lucky the 500hp vette due out will have a better MAF.

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:


Any updates on your fuel pressure situation? [/QB]</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No, I haven't ordered it yet, I've been told 5 time in 2 weeks I'm leaving tomorrow, but again I'm still here. I didn't want to order the fuel parts and then not be here when they get here, but I just might order them this weekend anyway.

Thanks for the information Mike.

XLR8NSS

iTrader: (4)

MightyMouse - I think the temperature in the PE vs. Temp. section of edit is referring to the coolant temp. That's what is says in the manual. That is not going to help you for air temperature changes. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

John

MIGHTYMOUSE

iTrader: (59)

hmmm.. that had crossed my eyes before, and would be a BIG wrench in the works for tuneability with the stock computer if it were true.. i started a thread in computer section about it.

<small>[ March 12, 2003, 06:10 PM: Message edited by: MIGHTYMOUSE ]</small>

Guido

I agree with both chris'.

John, I thought some people had the edsit going with the FAST on LS1's??

I can tell you firsthand that the FAST is nice if yuo can take advantage of all the capabilities.

QuickSilver2002

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Maybe if we're lucky the 500hp vette due out will have a better MAF.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I've heard it will have a completely different PCM (something like the trailblazers). The MAF still may work.