Drag Racing Results - Back to the track after 85mm MAF

I just finished putting a GM 85mm maf on my car and retuning it. Not claiming anything, just posting up the results so far. I would like to run again on a day with similar DA. If it wasn't such a pain in the ass to route the tubing and squeeze it over the larger MAF (I had to boil the pieces) I would do a back to back since I could just load the old tune easily.

Car ran 7.54@91.9mph 1.69 60ft in 1329DA with stock MAF (with screen)
Car ran 7.66@91.4mph 1.77 60ft in 2042DA with 85mm MAF (with screen)


This was a different track. I am not sure what caused the loss of 60ft as it hooked for both, unless it was a difference in staging depth or the DA and heat from the track was affecting it. My air filter is mounted low to catch air flowing under the bumper at speed, which means it is close to the hot pavement on launch.

Considering the DA difference, and different tracks, it's hard to compare. When you compare the .08 second 60' difference, and the .12 second ET difference, there isn't much to see (.04 seconds). Trap speed of .5MPH is the only main thing I can compare, and even then, the DA difference might eat up most of that.

I do appreciate you posting, though! I love comparing #s on before and after tests.

Was the lid, and bellow the same? (guessing since you mentioned boiling the pieces)

I did some calculations and between the DA and 60ft differences, the passes are as close as any 2 passes the car might make in the same day at the same track.

It's on the Chevelle to the intake track goes as follows:
850cfm K&N cone filter sticking 1" under bumper level (even with front sway bar when its on)
3" ID pvc straight up
90* rubber elbow 3" ID to 3.5" ID (fit is good on pvc pipe, stretched heavily over MAf inlet)
GM MAF
90* rubber elbow 3.5" ID to 3.5" ID (stretched over the MAF and 90mm TB)


It is this but with another 90* down before the MAF and the filter is hanging just low enough to theoretically catch air flow from under the car
http://img.photobucket.com/albums/v477/thunderstruck507/Chevelle/ls1019.jpg

You may need to recheck your tune.

MAF table was completely retuned using EFI live. I will double check to verify a/f again, but I doubt WOT a/f is off more than .2

I was tuning and with 12.6 commanded the wideband saw 13.1 so I added a touch back into the table but did not get to make another pull to confirm the change before the rain started.

Didn't expect to gain much if anything from the MAF swap, just wanted to post my results for others who might be debating it. I'm only out $45 and now I know I have room to grow in the future, so I'm not worried about it.

How much was the elbow you said is a bitch to change? get 2 with the maff pre fit to change with tunes at the track maybe?

Those 90 degree bends in your inlet tract kill some decent hp. Just like the GTO guys who run an over the radiator seutp vs a conventional CAI with sharp bends they see quite a difference.

How much was the elbow you said is a bitch to change? get 2 with the maff pre fit to change with tunes at the track maybe?

They are $20 each plus shipping. Not sure I want to make the investment just to get a back to back. I plan on selling the stock MAF to get most of my money back if possible.

Those 90 degree bends in your inlet tract kill some decent hp. Just like the GTO guys who run an over the radiator seutp vs a conventional CAI with sharp bends they see quite a difference.

Yeah I know, I am really jealous of the fbody/corvette/gto over the radiator design. Not only does it give a straight path but it allows use of ram air setups.

The only way I could do it would be with a custom hood with a cowl that runs all the way to the nose. There is less than 1" of gap between the cover and the hood there. I checked.

In the past I considered trying to make something that would work but it would have to replace the whole piece that covers the radiator and funnel down to something that would connect to the MAF. It would be similar concept as the tuned port 3rd gen setup. :

https://encrypted-tbn0.google.com/images?q=tbn:ANd9GcTJjM6KTb4QD_9iDZEPDyefFTvIr5sav m-wHK7jyYgFJZBZEdYoRA

I ultimately decided it would be extremely intensive to build and due to heat from the radiator might not even help

BTW, by the next time I go to the track I should be running on a 275/50r15 MT ET street instead of the too tall 325/50 I have.

Should be 2.5" shorter for more gear advantage and a little less weight. Should go from ~5000-5200rpm at the 1/4 stripe to over 5500rpm if I did the math right. Not sure what it will do to my 1/8th since it will make sure I hit 3rd before I cross instead of crossing on the limiter.

Nice comparison...I swapped once before at the track to an 85mm (no tune) and picked up .5 in mph also but I don't remember picking up if any in e.t. I need to look and see...

Being different tracks and different days its hard to say for sure. But any gain there was would have been a very small one.

Barely worth the trouble it took to get it on the car, never mind the $45, $20 adapter, and time tuning.

But you never know until you try and it gives me room to grow and it's one less thing I now know for sure isn't a restriction. Hoping to sell my stock MAF to get a couple bucks back.