Air to air Intercooler - fans or no fans?

JM PRO

JM PRO

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I am installing a intercooler behind my seats in a 2 seater. It will be installed in front of the radiator. I have plenty of room so I was planning on installing a large 24 x 12.5 x 3.5 core size intercooler. Air flow in this area will be marginal at best. There is a gas tank that hinders some air flow and the car has a hood and side panels that leave open a small area in front. I will attach a pic of the car for reference. Intercooler will be under the panel behind the seats and in front of the radiator.

Does anyone have real world experience with IAT's with or without fans and with similar air flow?

with 3.0 rear shocks.JPG
 
I have a 16x6x3 intercooler (supercharged) that gets some air pulled through it by the radiator. Without fans it can’t keep up, 120+ IAT. With fans <95 IAT.
 
May take some experimenting. Putting a fan on it in front of the radiator may disturb the cooling of the radiator. IATs aren’t usually bad with turbos as they are with blowers. Also e85 will help with that too. Obviously as cool as you can get the air is best.
 
JM PRO said:
I am installing a intercooler behind my seats in a 2 seater. It will be installed in front of the radiator. I have plenty of room so I was planning on installing a large 24 x 12.5 x 3.5 core size intercooler. Air flow in this area will be marginal at best. There is a gas tank that hinders some air flow and the car has a hood and side panels that leave open a small area in front. I will attach a pic of the car for reference. Intercooler will be under the panel behind the seats and in front of the radiator.

Does anyone have real world experience with IAT's with or without fans and with similar air flow?

View attachment 169847
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its all a guess if you dont have any real world data.

ideally you would install a temp sensor after the turbo, and measure the temp delta after the intercooler.

what fuel are you running as this will have a big impact on what you can get away with.

if you choose to run a fan, you can run it all the time but the reality is you dont need it as until you make significant manifold pressure, the temp wont warrant it.

looking at the pic of your car, why put the intercooler down low in front of the radiator? why not a wide low profile intercooler laid back ABOVE the radiator where you would have good airflow? in this situation i wouldnt bother with a fan. good airflow, proper sizing i have seen greater than 100F temp deltas.
 
daveH said:
its all a guess if you dont have any real world data.

ideally you would install a temp sensor after the turbo, and measure the temp delta after the intercooler.

what fuel are you running as this will have a big impact on what you can get away with.

if you choose to run a fan, you can run it all the time but the reality is you dont need it as until you make significant manifold pressure, the temp wont warrant it.

looking at the pic of your car, why put the intercooler down low in front of the radiator? why not a wide low profile intercooler laid back ABOVE the radiator where you would have good airflow? in this situation i wouldnt bother with a fan. good airflow, proper sizing i have seen greater than 100F temp deltas.
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I am running E85.

I am currently at 14 pounds of boost but have future plans to go 20 pounds.

I could run it above the panel behind my seats and in front of the radiator but I have a ton of room below the panel and like the clean packaging. Function vs fashion is what I say in the construction world. As long as I can make it work efficiently I will put it under the panel.
 
JM PRO said:
I am running E85.

I am currently at 14 pounds of boost but have future plans to go 20 pounds.

I could run it above the panel behind my seats and in front of the radiator but I have a ton of room below the panel and like the clean packaging. Function vs fashion is what I say in the construction world. As long as I can make it work efficiently I will put it under the panel.
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at 20lbs you will see outlet temps probably north of 225F. even with e85....I would want all the intercooling i could get.
 
Kraut_n_Rice said:
Is your current intercooler insufficient?
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yeah good point. what are current IAT's? also keep in mind, with the longer plumbing, quality of the intercooler you choose.....you could make situation WORSE. when it comes to intercoolers.......dont skimp........I have seen plenty of cheap IC's that were knocking lbs of boost out of the system......let alone do a good job cooling.
 
Kraut_n_Rice said:
Is your current intercooler insufficient?
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I have no IAT gauge, only me touching the inlet and outlet of the intercooler. After a hard run the 3" outlet tubing is warm, I would guess in the 115-120 range. inlet is much hotter. The problem with current intercooler is location of the radiator which blows right at the engine and intercooler resulting in heat soak that can't be fixed unless moving the radiator. Plus the natural heat coming off the engine that heats the intercooler. It's just not an ideal location for my car. Plus I don't like the look of the scoop and additional height it adds to the top of the engine.
 
JM PRO said:
I have no IAT gauge, only me touching the inlet and outlet of the intercooler. After a hard run the 3" outlet tubing is warm, I would guess in the 115-120 range. inlet is much hotter. The problem with current intercooler is location of the radiator which blows right at the engine and intercooler resulting in heat soak that can't be fixed unless moving the radiator. Plus the natural heat coming off the engine that heats the intercooler. It's just not an ideal location for my car. Plus I don't like the look of the scoop and additional height it adds to the top of the engine.
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get a guage so you can log temps. it might justr save you time, money and even performance.

I would also make note of ambient temps when you run it as this will effect air to air performance.
 
I dont know why this is even a debate?
the only right answer is what grease monkey said, put the best spal fans on it and run them all the time unless you have ability to control these fans by air temp too.

putting on temp sensors and checking pre and post intercooler temps are great, but here is the deal---you want the intercooler to have icicles!!!
you could never have it too cold

also just because the intercooler is in front of the radiator, do not expect the radiator fans to do any of the intercooler cooling. radiator fans only come on for engine water temp
 
totally agree with john......there is no such thing as too cold. there are limits though. you will never get an air to air intercooler to bring temps below ambient. so hitting it with a massive over sized intercooler and/or monster fans may only end up making installation challenging or waste $$ on oversized components that you didnt need after all. thats why i would at least collect some data before just jumping in blindly. on top of that...everyone seems to think power is free and just run whatever fans or lights and so forth.......there are limits there too.

It is possible to use your radiator fans "double duty" for the intercooler. the only down side would be if you didnt have a coolant thermostat as you could potentially drive coolant temps down excessively. this can be down with a PDM or a temp switch wired in parallel with your rad Fan relay. a PDM is a way better way to do it as now you can also have control strategy based on things like vehicle speed as well.
 
yes while we are talking intercooler sizing, it is something done on the dyno, you would make back to back full throttle pulls with a pressure gauge on both sides of the intercooler, industry standard would be in the 1-1.5psi delta range, lower than that, then the intercooler is excessively large, smaller than that and you are making heat and restricting flow. i have seen cars come into my shop with 8-9 psi delta 😲
 
John@Outfront said:
yes while we are talking intercooler sizing, it is something done on the dyno, you would make back to back full throttle pulls with a pressure gauge on both sides of the intercooler, industry standard would be in the 1-1.5psi delta range, lower than that, then the intercooler is excessively large, smaller than that and you are making heat and restricting flow. i have seen cars come into my shop with 8-9 psi delta 😲
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While I would love to be able to dyno test different sized intercoolers for max efficiency, it just isn't in the cards. With your experience, for my 3.5 Honda tuned for 16-20 pounds of boost which size intercooler should I be installing? I have no size restrictions where it is going and I will be installing fans on it. The tubing length on either side of intercooler will be under 3' long. I was thinking 2.5" on the inlet side and 3" tubing on the outlet side.

next question is what intercooler brand do you recommend? I want to avoid the pitfalls of buying a cheap brand or under or oversizing, so I greatly appreciate everyone's input.

I am currently looking at the Treadstone brand P/N TR12C, 12.5" x 22" x 3.5" core, rated at 760 HP and flows 1200 CFM.

www.treadstoneperformance.com

Treadstone Performance Inc., Turbo Kits, Intercoolers, Turbo Manifolds, Silicone Hose

Treadstone Performance
www.treadstoneperformance.com www.treadstoneperformance.com
 
That intercooler looks great. There are two dimensions in play. The first is the “ charge face” which is the side where air enters. That is 12.5x 3.5=43.75 sq inches. My intercooler for up to 500 hp has a charge face of 36 sq inches so yours looks really reasonable. This is the dimension every gets wrong that has a high delta. I have seen long skinny intercooler that people put on and the “charge face” is like 3” x7”. That’s only 21 sq inches and they put them on Hondas and get 8 psi delta. You are in the ball park with that one. Then the length is secondary. But the longer you have the more fans you can install and cooler the air gets. It would be nice to see a pair of HD 11spal fans on there. Or even 12” ones that hang over the tanks a tad
 
The tubing: if your turbo outlet is 2” then you can actually do anywhere from 2-2.5” to the intercooler. If 2” then you could actually start stepping it up along the way. For example do 12” at 2” then wedge it open to 2.25 and s distance and then finally 2.5”. To me it looks funny if you have a 2.5” tube meet a 2” outlet on the turbo. From intercooler to throttle body can be 2.5- 3”. I would not be concerned at 2.5 inches all the way because it’s no longer a NA but boosted. It’s a lot easier to work with 2.5” tubing. And then have a reducer hose at throttle body ie: 2.5” to 3”.
 
Lastly. I have always felt pulling air through an intercooler with a fan(s) shroud is always better then pushing it from the front side ( just like radiators) so if you have room then…..
 
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