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034 fitment of silicone boot for 7A big MAF

2K views 2 replies 2 participants last post by  ejfluhr 
#1 ·
I'm trying to fit the silicone "big MAF" instake boot onto a 7A stock airbox with an AHA MAF and cannot get it to fit. The alignment of the top is rotated by 5 degrees or so, counterclockwise when looking straight down. The silicone boot is too strong to flex and won't allow the top to snap into place. Has anyone else made this work with the factor intake, or does everyone go with a cone filter because it doesn't work? If a cone filter is the common approach, is there an off-the-shelf adapter that works or does it need to be custom-made?
(My preference is to run the stock airbox.)

Thanks,
Eric
1990 90q20v Team Unintended Acceleration (ChampCar series)
 
#2 ·
Eric: I've had to trim the boot at an angle to get it to fit with the MAF and stock airbox and even then its a forced fit
 
#3 ·
Interesting...where did you trim it, at the MAF or throttle-body or both? Is it uncomfortably tight or does it flex enough to allow for decent engine movement? We have stiffer motor mounts but it's racing so the engine still moves around a lot.

I found that Vibrant Performance sells an adapter to fit a cone filter on the AHA MAF. Part number 1998, can be found on Amazon. A cone filter costs us points for car valuation so we are trying to keep the stock airbox, but I wanted to document this option in case anyone else finds this post and is looking for ideas.

In case others are interested here is a bit of info about the big MAF upgrade on our car. We installed a wideband O2 to monitor fuel ratio and tune this kit (I had to make a MAF adapter harness). We are running the 034 7A injector kit with some kind of a TAP-modded ECU. Before installing the big MAF, we were running below 12:1 air:fuel ratio at WOT (too rich, yuk). I'm still testing and trying to dial in the MAF, but I've got it just over 13:1 right now at WOT (from 3K to 7K RPMs) which is about where I want to park it. So far, the engine clearly seems to hold power better from 6K RPMs and up, hard to tell below that without comparing lap times (we may do that). The car has no muffler, but the exhaust pipe is the stock "skinny" diameter so a larger pipe (in the works), may combine with this mod to yield further gains.

I'll also throw some praise to the often-maligned 7A...it is one reliable beast. I think we have more than 20 endurance races on this motor now, most at 8 hours but a couple in the 18-24 hour range, and it was already a 200K-mile motor before that (never rebuilt). So I've become a 7A fan-boy now...

Thanks, Eric
 
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