</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by scott ws6:
<strong> Just do what I did and install the fast system <img border="0" alt="[gruffy cottonball]" title="" src="graemlins/gr_gruffy.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Scott...I think Im with you man. I got a built iron motor with a T-88 sitting on it.....it scares me to saddle it with a badaid system, that you have to worry about every time you go WOT. I mean, Gen 7 dfi is ~1500......with all the money invested in the motor/turbo, its just cheap insurance. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Chris

 

how much for the granitelli box? link?

from Jim Gonzales at Pro M

"We can sell you a frequency converter or tuner and you can do it yourself for $400 or we can sell you an analog meter that we convert to frequency, the converter would cost $350 but the meter would be incremental based upon the size that you chose. The meter that we did prior was a Univer which lists for $399."

I'm a little confused by that, but the price is steep for me right now. Especiall if he meant AND instead of OR like it seems half way down the reply.

 

I'd love to have it, dont get me wrong but, I'm not smart enough to make new waves in this area.. So the aftermarket systems need to be proven AND easy, before I stick my foot in them.

It would definitely make it easier if I would write off the purchase. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Harlan doesnt band-aid anything, heck he's got like 7 fuel lines running into the engine bay <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> .

 

For a FI setup (one that maxes out the MAF) an aftermaket fuel injection system is without a double worthwile - but it's also extra money and hassle. It probably is the best way though.

Chris:
The Gen7 DFI looks very nice - I had heard they had some issues with the wideband o2 sensors, and didn't know if they ever fixed those. Also I had heard that the software allowed the EMIC's to lock certain tables so they weren't accesable? I haven't really followed up on any of those rumours so they could all be just that.


</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">
"We can sell you a frequency converter or tuner and you can do it yourself for $400 or we can sell you an analog meter that we convert to frequency, the converter would cost $350 but the meter would be incremental based upon the size that you chose. The meter that we did prior was a Univer which lists for $399."

I'm a little confused by that, but the price is steep for me right now. Especiall if he meant AND instead of OR like it seems half way down the reply.
</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">

That is a little confusing - my *guess* would be the converter is a piggyback device like the MAF-T that allows you to adjust things as you see fit.
The analog meter conversion sounds like they are taking a mustang type meter, converting the output to frequency, and offering that. Depending on the dynamic range that may be an ideal solution - but you would need to get a detailed chart from them of flow vs. frequency - or flowtest it yourself with an o-scope and a flowbench.

As for the stock computer being a hack - I think if you can do a dual maf setup or somehow meter all the air, it wouldn't be a hack - both fuel and spark would be metered by incoming airflow (spark by g/cyl) - so as long as you are within the limits of the pcm tables it would work very well - and I don't think any aftermarket DFI can offer the same drivability of a properly tuned stock computer - simply because GM can invest 100x the amount of money in development. Plus I prefer MAF metering over SD if you can get it to work properly.


Chris

 

I agree with you 100% ChrisB...very well put. The stock system would work perfect, if you could meter the air accurately at those increased levels. After having to buy a injector box, a custom meter....I will still be left with the fact that the computer couldn't compensate for boost changes at high levels of flow accurately. I have visions of a/f curves shaped like the rockey mountains <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> The Ls1 is a very docile motor...and not hard to tune at all compared to some....I think Gen 7 with a 3-bar map and some nice big injectors, will make for less motor swaps <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Chris

 

What about just letting one MAF be a "dummy",
and just use injectors with 2.0X the flow rate?
Then it all comes down to matching the plumbing,
so the 2 MAFs make 2.0X the airflow and the
injectors make 2X the fuel flow, right?

 

earlier posted by chisB

"re only metering one tube: I tried that on a friends D1 LT1 - a dual path intake with 2 maf's, but only metering one. It worked to a certain extent - it proved the viability of the 1/2 injector size trick, etc. - part throttle drivability wasn't good, and logging the other maf with a oscilloscope showed the flow through both was not perfectly equal. That is going to be the problem - getting them matched. It's much better to meter both and average it."

 

this probably is a definite no.. but

are there replacement resistors available that could be swapped with the ones in the maf tube that would generate a lower hz response?

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by ChrisB:
<strong> That is a little confusing - my *guess* would be the converter is a piggyback device like the MAF-T that allows you to adjust things as you see fit.
The analog meter conversion sounds like they are taking a mustang type meter, converting the output to frequency, and offering that. Depending on the dynamic range that may be an ideal solution - but you would need to get a detailed chart from them of flow vs. frequency - or flowtest it yourself with an o-scope and a flowbench.
</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">That is exactly what my shop had Pro-M make for us.

all of their univer-MAF's are the standard voltage out, 5 wire, hitachi guts in a custom external sample tube type MAF. The sample path is out of the direct flow path of the air making it suitable for a blow-through application. The sample tube relies on a pressure drop across a smoothed step change in the inner-diameter of the meter to pull air through. You get a constant size sample tube with a scalable meter diameter.

It came w/ a "GM LT1 MAF Voltage to Frequency" converter. My guess is they have thought about it in the past. They flowed the entire setup just like they normally do, but collected frequency instead of voltage.

We got a full plot of the MAF curve from the zero-flow ouput to 12kHz, along w/ actual data taken and the standard hot-wire curve fit.

Why they haven't picked up the hitachi guts from the 3800 series MAF's i don't know. It's the same style meter, but w/ the GM output stage.

My only concern w/ the setup is the temperature sensitivity. So far so got though, as i'm guessing the underhood temps are pretty constant. But, so far i've noticed no real shift in output with changes in temp.

And yes, i've tried to investigate what's in the converter, but like any good electronics place they filled it w/ potting epoxy <img border="0" alt="[judgement]" title="" src="graemlins/gr_judge.gif" />

Here's the curve on my Univer

<img src="http://www.harlan-engineering.com/hawk/pics/MAF_Curve.jpg" alt=" - " />

if you do the conversion from kg/hr to g/s the 4500 point is over 1200 g/s <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

I see peak numbers in the 10khz range right now.

 

That looks interesting for sure - and will definitely work as a single MAF setup!

Did you provide that calibration sheet, or did pro-m? Do you think a normal flowbench would work for calibrating a meter (converting to massflow from CFM, etc.)?

Re: the conversion electronics - any reason one couldn't just make a little adapter with a microcontroller to scale the voltage to a frequency output? Once you have the calibration sheet it should be pretty easy.

Regardless, this is a solution that looks like it will work very well! If one wanted to get the same setup you have would pro-m offer it, or would we need the converter box/to source our own MAF meter?

Thanks,
Chris

 

finally got hold of the actual 01 ls6 maf scale tonight.. REAL crappy that at my pcm's max of 11250 hz the maf is only flowing 349.5g/s <img border="0" title="" alt="[Frown]" src="gr_sad.gif" />

so i will have a lot of pe table tuning on the rest of the rev range (wherever the flatline rpm starts) this is probably not very safe to rely on that heavily.. right?

i would really HATE to drop another 800 on the car for the maf.. but i guess if you gotta, you gotta. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" />

 

it really looks like my stock maf with the higher g/sec at 11250hz would be the best choice... i wish i knew what fastchips did to the ls1m test cars to make the 85mm meter so hospitable for that airflow. <img border="0" title="" alt="[Frown]" src="gr_sad.gif" /> i'd sure like to take advantage of its size.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">I see peak numbers in the 10khz range right now.</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Harlan - I was just looking at your MAF flow chart and 10KHz equates to around 830hp. <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

That would probably get you REAL close to an eight second 1/4 in a properly setup AUTO. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

MIGHTYMOUSE - You decided on what your gonna do MAF wise?

John

 

xlr8n, i still have not heard any more about the granitelli unit, admitted i have not done any looking..

i might as well and do it the right way (see mr. right way's post above)

but i dont want to have too many things going on at once, the plan for now is to get the kit and run around at 9 until i get the tuning perfected, then start moving up, hopefully i will outflow the stock hz around this range and then i will put more into the notion of going for the gusto. *note that lots of stock maf cars have done well at 600rw with the stock maf adjusting the pe table* so im not trying to do the impossible by starting off keeping it. i just have less help from the computer to come up with the fuel it needs on its own.

on the other hand, if my goal was just a bit lower, i would probably definitely go with the maf that jas offered to tune that can measure accurately to 512 at 11250hz. for most that will be plenty, and you dont have to get into the hassle of splitting tables like matt does.. much more user friendly.

I would really be interested in getting with pro-m in developing a plug and play 150% maf that came with simple instructions on what numbers to cut up in edit. this would be very popular if they could do it for $400-.. i think i'll email about that now.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

 

Sounds like a plan. It's a good thing not to get too many things going at once. It makes it that much harder to diagnose if there is a problem.

I'm not sure what you mean by 150% MAF. What would the limit be of this 150% MAF?

Keep us updated on your talks with Pro-M. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

John

 

well being they havent yet replied to that email i sent, its really premature to have anything set but as the topic goes.. it would be easiest for me to provide the tuning for a maf they make by using a factor of 2.

this means the new limit would be around 900g/sec or 3420kg/hr on harlans graph there.. this makes the math easy. using what the guys said above. this would cover cars up to around 900 fwhp... which i figure is not bad <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

 

pro m's reply


"We already have a plug and play for GM cars and it lists for $299 and you can convert you meter to whatever you want. I appreciate the offer, thanks anyway. "

this is the granitelli maf hz adjuster hes talking about.. i guess they didn't get that i didnt want to splice between the stock meter and computer, but to replace the stock meter with one more accurate

here's there info page on it.. doesnt seem to do what i'm looking for, i guess they dont want to make more money.

http://www.pro-flow.com/Instructions/16k.htm

<small>[ January 31, 2003, 04:59 PM: Message edited by: MIGHTYMOUSE ]</small>

 

Harlan - You said that your Univer MAF came with a "GM LT1 MAF Voltage to Frequency" converter. I'm assuming that it's NOT the same thing as in the picture below? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" /> How do you set the frequency range on it? In other words how does it know that the 0-5volt signal from the MAF correlates to a 0-12KHz frequency range. Is this something Pro-M(Pro-Flow) preset knowing you had a 0-12000Hz range to deal with or does the converter/MAF have to be dialed in on a flowbench before being installed on the car?

<img src="http://64.127.132.31/pics/gm.gif" alt=" - " />

Thanks

John<--I think I'm starting to understand a little better. Pictures and diagrams would help though. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" /> <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

<small>[ January 31, 2003, 10:27 PM: Message edited by: XLR8NSS ]</small>

 

Harlot...Uh, I mean Harlan. <img border="0" title="" alt="[Razz]" src="gr_images/icons/tongue.gif" />

TTT <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

John