stacking heat exchangers

[rojizostang]

in the never ending quest for lower ait2f's....I apologize for the long read but want all the appropriate information for those who are interested:

I have ideas from time to time to improve efficiency, without spending tons of cash. (the saving money part usually doesn't work out, lol). currently i'm waiting on an exchange for the '13gt500 intercooler pump I bought as the first one appears to be defective (it's to be installed as an upgrade over the standard bosch pump). that's the first upgrade for the system. the second upgrade i'm considering is rearranging/changing the lower heat exchanger for a different unit in a different location, in a stacked arrangement in the grill.

on my 2013 roush supercharged 5.0 f150, the current arrangement consists of the stock roush lower heat exchanger (24x5x2), the stock bosch pump everyone uses, and the upper roush heat exchanger 22x16x.75 they sell for mustangs/f150's (however not the high capacity heat exchanger) and the stock roush degas bottle for the kit. in addition I have a 14" 1850 cfm fan pulling thru the upper heat exchanger. ait's run 120 to 130 in 80 to 85 degree weather. also I have a pair of hood louvers to help evacuate heat from under the hood. included also is of course the intercooler under the blower

So, to me there's some concern that the air pathways to the radiator are impeded. both by the upper HE behind the grill, and the lower HE behind the bumper. coolant temps only rarely reach 200 degrees, however I think that lower coolant/engine temps, lower ambient temps under the hold, and improved heat exchanger operation can all contribute to lower ait's.

when I installed the upper heat exchanger as an upgrade to the system (that was the first upgrade actually to the system which took place shortly after the blower install) I was unaware of the same heat exchanger that is basically double the size of the one I installed, but it also costs like $600 without fans (so i'm sure I wouldn't have bought it anyway)lol. I paid $82 for the current unit.

ok, after all that, on to the idea;

I'm thinking of removing the lower heat exchanger behind the bumper, and replacing it with a unit available on ebay, with dimensions of 22x10.5x1.75. The thought is to take the ebay unit, and stack it in front of the upper heat exchanger. It's the perfect size to fit in the available space. the idea is that in this position, it will see improved airflow at idle, as it will be in front of the fan, improved airflow while driving, since it's in the grille, and also the radiator will see improved aiflow since the area behind the bumper will be free of the current heat exchanger and create better airflow to the lower portion of the radiator itself.

the effect, I believe could be like using a dual pass heat exchanger of sorts with mechanical cooling at idle, along with improved airflow to the radiator. in addition of course will be the upgraded gt500 pump.

here's the heat exchanger i'm considering as a "stackable" unit"
http://www.ebay.com/itm/322066647758?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

here's the current upper heat exchanger
http://www.ebay.com/itm/New-Roush-F...ash=item2cab58e069:g:npgAAOSw2ENW8aoP&vxp=mtr

this is similar to the lower heat exchanger behind the bumper which I plan to remove
http://www.ebay.com/itm/2003-2004-0...ash=item35ff090822:g:RDkAAOSwiYFXDeH8&vxp=mtr

basically I would have the heat exchangers in the first two links stacked behind the grill in front of the 14" fan with the upgraded gt500 pump as the new intercooler/heat exchanger system. the new intercooler pump would be sandwiched between those two heat exchangers, and the area behind the bumper would be cleared of the lower heat exchanger to help improve airflow to the radiator

a little math to boot:

new unit dimensions 22x10.5x1.75=404.25 cubic inches of cooling area

existing lower unit dimensions (approximation) 24x5.5x2=264 cubic inches of cooling area

thoughts by those who are interested/experienced in this stuff?

 

[skaarlaj]

I think it's alot of work that'll net you very little imo. Say you drop your iats at the end of the quarter mile by 8*, you won't know the difference, the dyno......... maybe, but probably not. I was always chasing cooler iat's with my 04 Cobra, and one winter I put my BBK CAI's air filter into the fender, instead of the common shielded set-up you see alot, and it did decrease my iat 1, and 2's by over 15*, and my best times were with the prior set-up regardless of the ecu not pulling timing at the end of the 1/4 and an additional degree of timing added with my hand-held. So yes it helped with iat's, but other than numbers on a datalog............worthless at the track. A new set of drag radials would've been money and time more wisely spent.

If you were seeking long distance wot runs or towing at wot, or un-intercooled all together, Id say do it, but I just wouldn't expect too much in your case.

 

[rojizostang]

thanks

daily driver, haven't been to the track with it yet

the tune starts pulling timing at 120*, fwiw, if I was correctly informed. mostly this truck is a hobby. so in the end, right, none of it makes much of a difference.

the basic question is stacking heat exchangers a viable idea with predictable results? as far as the amount of work that's involved...not all that much. everything is up front (pun intended) and easily accessible.

 

[Wes06]

Look up department of BOOST
He had a track car with two heat exchangers, however one was in the trunk and had air flow into it

Can't remember how much it helped but I'm sure it's there

 

[skaarlaj]

as far as the amount of work that's involved...not all that much. everything is up front (pun intended) and easily accessible.

Well hell, if it's relatively easy and cheap for ya, get her done and come back here with your results man!! I can't seeing you hurtin anything by trying it out, just verify liquid flow back into your de-gas tank after you get it plumbed together.

 

[rojizostang]

Well ok then, even though cheap and easy are relative terms, lol.

 

[808muscle]

My friend and I have been thinking of doing this on his stang. Seems two would be better. He has a roush setup which is so small. He wants to add my old roush unit to double his capacity. Will report the results if we can get it done.

 

[eighty6gt]

Roush stacks their exchangers on the F150's - crappy lower one, full face upper. Charges $700 for the full face upper you can buy on ebay for $80, too. Smart company.

Almost as smart as DOB, who have already done all of the difficult, expensive field work and have cracked the nut. There are creative ways to do things, and expensive ways to do things. Cruising into uncharted territory... if it works, then it was worth it. Otherwise just getting in on a dob cooler would be way more worth your time.

Finally, I think people are more afraid of high IAT's than they need to be.

 

[rojizostang]

Finally, I think people are more afraid of high IAT's than they need to be

might be true.

for me half the fun of this hobby is figuring out a less expensive way to net positive results. I'm not always successful, but it's a big part of the fun for me.

 

[hammeron]

the pcm can also start reducing ignition timing based on engine coolant temperature, it could be at 210f or a little lower, only your tuner could give you exact numbers.

as far as the air charge temperature, a ballpark range is 0-138f there is no reduction. 139-144f its -2 degrees.
145-175f its -6 degrees. 176-200f its -8. only your tuner can give you exact numbers.

 

[rojizostang]

the pcm can also start reducing ignition timing based on engine coolant temperature, it could be at 210f or a little lower, only your tuner could give you exact numbers.

as far as the air charge temperature, a ballpark range is 0-138f there is no reduction. 139-144f its -2 degrees.
145-175f its -6 degrees. 176-200f its -8. only your tuner can give you exact numbers.

I don't know the exact numbers, but it starts pulling timing supposedly at 120*, according to the tuner. it's tuned pretty conservatively, I believe. so far i'm able to keep engine coolant temps under 200*

i'm also looking to a local guy for a little more aggressive tune, including getting the transmission to shift more quickly

anyway I just bought the heat exchanger in the link. once I get all the parts here, i'll rework the entire system. I may even try it with 3 heat exchangers first.

the DOB manifold/intercoolers are awesome, but a no go, at least for a while.