Im gonna put a BHAF in my 95 where the battery tray is for the duals since Im runnin 1 battery. Is it really necessary to do a heat shield? even if the air picked up is a little warmer its still subject to what the intercooler cools it to. Right? It would seem that under hood temps will still surround a BHAF with a heat shield. Also are the stock airbox retainers bolted from under the fender liner or? Mine is real loose on the fender well.

 

FWIW From all my reading here and on other sites it seems to be best if you use cooler air than warmer air.....I suppose you could still get some benefit from simply having a larger filter that flows more air than stock but probably best to get the coolest air possible. Hope this helps. Good luck on your project...

 

I used to run a comp with an uncovered BHAF and I never saw over 1000* pre turbo. Wire tapped. That same BHAF is on my roommates truck and has over 60K miles on it and even with a comp and mach 1.5's, his egts are still at 1225* pre turbo. His is uncovered as well.

 

The BHAF in the stock airbox location is really close to the turbo, thus the need for the heat shield.

It is more to keep the BHAF from melting than locking out underhood temps, but it kinda does that as well.

I would think if you put it on the battery tray, that would be far enough away from the engine that you wouldn't neet a heat shield.

I would also think that it might get wetter there though, so you'd want something to keep the spray away.


phox

 

FYI.....This is part of a thread I saved from knowledgable member (Infidel) who did underhood temp testing. Thought his results might be of interest to you and, in part, answer your questions.
-------------------------------------
"It's hot everywhere under the hood. My intake temp as measured at the intake horn a few inches from the grid heaters is almost always a constant 20° higher than the outside temp with the stock airbox.
With the BHAF it was 26° higher. 6° may not seem like much but it's more than 25% hotter than the stock box.
I've never figured out how intake temp relates to egts, it's probably a complex formula, but am certain it isn't a one to one ratio. I'd venture to say it's more like 10° or more higher egt for every 1° rise in intake temp."
--------------------------------------
Think you will find the Charge Air Cooler (intercooler) will only cool X degrees below the air it is fed....so lower intake air temps using a heat shield helps keep EGT's down. That's how I see it anyway.

RJ

 

I was wondering if anyone had tackled that one. I was considering setting up something to check temps as Infidel did. As in Phox`s case I saw in his pics the BHAF is in the stock box location. That would be a problem IMO due to it being right by the turbo. I guess Im gonna experiment with it on my battery tray location and shelid it from H2O etc. The stocker is filthy already and its only 5k old, I dont like the way it seals either. Now with the ring out I wanna hear it singin some more.

 

yeah, i don't like that filter being right there by the turbo either. i bet the ratio is at least what r johnson said--1:10 that sounds a little light to me. if your underhood temps are 20 degrees hotter than outside temps, then thats a lot of extra and unwanted heat. i'm not real sure on how to fix that problem, but i will fix it one way or another when i get my rig rollin, ill keep ya'll updated.

 

As far as I know, I was the first to run the filter now known as a BHAF, my initial post on it was titled Big Honking Air Filter. Thankfully, someone shortened it to BHAF. I've run the Fleetguard and Napa filters for years on my truck, my wifes 98 12v and friends trucks with no heatshield or cover with zero adverse effects. Zero.

I've also used a totally enclosed stainless housing on a BHAF that tied into a 4" hole in the freshair duct and stock freshair connector as the Scotty housings do with insulation on the turbo side of the housing. The result was it looked kool, but there wasn't a substantial difference in EGTs.

Currently, the wifes truck has a BHAF laying where the stock housing was. My 95 at the moment has one it the same location.

I was running the AFEProguard7 that's in my sig with the aforementioned housing, but it showes signs of distortion, kindofa twisted, simi crushed look. So it's on the workbench at the moment.

As a aside, the AFE didn't show a drop in EGTs over the Fleetguard BHAF.

RJR