LS7 MAF on 3800

[Overkill]

Call this an exercise in teaching an old dog (read: the 3800, not me) new tricks.

We've been using the "LQ4" "85mm MAF" that was originally introduced on 1999 GM vehicles with our Northstar upgrade kits (and LS1 upgrade kits before that, that's how old it is) and in particular those who are going to buy them used at junk yards are often buying 10 year old sensors.

Since then, the LS7 card MAF (now used on LS3 and other) has become a popular upgrade on other applications and I decided to try it on the 3800.

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Benefits:
-Very new and accurate sensor, fast updating
-You can buy aftermarket MAF housings in full 4" (100mm) size for great flow
-Not that expensive to set up with all new parts

For the test, the parts involved were a polished aluminum 4" MAF housing, a low restriction honeycomb screen, an OE manufacturer brand MAF that was confirmed "strong" (google "strong ls3 maf" for more info), and a wiring harness adapter for this specific sensor swap.

Here's an installed photo from a very nice 2004 Monte Carlo SS. Owner had installed one of those JMB intakes which is a full 4" piping, along with a Northstar throttle body upgrade. Rather than necking down with the 85mm truck maf that normally comes with the Northstar kit, the setup retains 4" straight through.

ls3maf5.jpg

Once I'd developed the MAF calibration curve, my observations were:
-a nice crisp throttle response, which isn't always achieved with a large MAF housing
-MAF frequency at WOT reduced by roughly 2000 hertz, meaning that although it's easy to max out the frequency even on the 85mm truck MAF, this MAF will provide lots of headroom and support any supercharged setup

Only issue so far is the IAT sensor built into the MAF is calibrated different, and I'm still trying to source the coding inside the PCM to recalibrate it. The fix for now is simply reuse the factory IAT sensor as we did here.

Turbo guys: Instead of using the even older metal "LT1" MAF, which is now 20 years old (!!), this could be the ideal MAF setup. This card MAF should provide lots of headroom in frequency, and combined with a housing with a low restriction honeycomb screen it should flow better than the LT1 MAF. While the housing I used on the supercharged setup was a thin aluminum housing, I've sourced a much sturdier housing for turbo use.

I may make up kits if there's interest, for those who want to ensure they get the right mix of parts to set it up. For now, I'll simply say yes the LS7 MAF works well on a 3800, its nice to use such a new and up to date sensor, this is something I recommend and yes this does mean I can now tune for it *thumbs up*

[16MustangVet]

Awesome info! Its very nice to see what can be done using better parts that are already available!

[wa04compg]

Great info!

[darkhorizon]

We used these in a few cars when they first came out and they sucked. The 4inch tube is a available from spectre now and it is ok.

If you have a big sc setup and want to make a nice intake that flows over the maf well go for it but otherwise for turbo its a pain in the ass. I swapped a turbo ls3 vette I tuned from this maf to a 20 year old lt1 and it ran worlds better.

[Overkill]

I swapped a turbo ls3 vette I tuned from this maf to a 20 year old lt1 and it ran worlds better.

Were you using a honeycomb screen on the ls3? What size maf housing? What was the issue, how exactly did it suck?

[darkhorizon]

No screen before. The spectres have screens but they are stilll annoying compared to an afc on a lq4. Afc lq4/stock/lt1 is still about the same cost with much better results out of the box.... if you wanted to tinker enough with a slot maf then go for it it has a chance of working pretty good.

[darkhorizon]

The problems we had were just consistency issues. Wasnt ever as temperature or humidity friendly as the stock configuration mafs were. Cold idle was different than warm idle... knocking the airfilter around and a warm saggy coupler caused issues. Just got to the point that we would have never done it again due to the variability we found when trying to replicate it onto another car after we thought we had a good maf table done... it worked but just not as well as other options.

[91parkave]

Use the saxonpc honey comb its the most accurate I outlined this already http://www.grandprixforums.net/threa...-MAF-installed

[Overkill]

Use the saxonpc honey comb its the most accurate I outlined this already http://www.grandprixforums.net/threa...-MAF-installed

Used one on this test and I agree they work well. You can also buy better quality housings than Spectre with a machined groove to hold the screen in place, I think I'd use those on blow through turbo applications.

Dark, the Spectre housing doesn't come with a screen. Would be interesting to see how your results varied with a better screened housing. I've had no issues with the card MAF on other applications including supercharged but those were draw through setups. Limited experience on blow through Cobalt/G5 turbo setups with the same MAF but again no issues warranting a MAF swap.

[darkhorizon]

Ok maybe I didnt.. this was 4 or 5 years ago...

I did fiddle with some turbo cobalt in a 3.5in tube and it ran ok... really needed alot of bumps in the maf curve for it to run decent.