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Should the pre heater hose inlet from the airbox be capped off?

Joined
Nov 22, 2017
Location
California
So I did the flapper removal mod a couple months ago and put netting on both intlets to prevent large debris from entering the airbox. After driving for a while, I opened the airbox up today and the filter was still clean (other than the black marks it gets from trying to set it in place correctly). Should I keep the preheater inlet open, but kinda protected by the netting, or completely capped off in a dry place like California? Is it placed in a spot that would suck in a lot of water when it rains (if it ever does here)?
 
IMO it doesn’t really matter. Whatever your preference.

If you have a belly pan in place there isn’t going to be much water splashing around if you would drive through rain.
 
I never capped mine at all. Had no issues. This was on my winter beater too so... gnarly conditions.
 
I had the flapper closed for a long time in my 245. But recently while I replaced the air filter I also made both air intakes cold air. The engine liked that. So I would suggest have both go to cold intake air. More air easier to suck in.
 
I had the flapper closed for a long time in my 245. But recently while I replaced the air filter I also made both air intakes cold air. The engine liked that. So I would suggest have both go to cold intake air. More air easier to suck in.

Yeah the engine has been happy since I got rid of the broken flapper. More air seems like a good idea. I think I'll keep it open for air, a belly pan would be on my list of things to get, but not a priority.
 
I have one of the URO pans and it works fine. I did have to enlarge some of the bolt holes so they lined up, but that was a minor inconvenience IMO.
 
Snorkel to the airfilter box is a huge restriction even on a stock engine. Adding a second cold (ram) air intake hose will make a small but noticable difference.
 
Cap it off to get only fresh air from the factory cold air intake. I don't remember the default position of the flapper, but you want it modded to hold against the heat pipe port, that way only fresh air comes in through the front port. After that it probably doesn't matter if it's capped, but it will look better if it is.
 
Cap it off to get only fresh air from the factory cold air intake. I don't remember the default position of the flapper, but you want it modded to hold against the heat pipe port, that way only fresh air comes in through the front port. After that it probably doesn't matter if it's capped, but it will look better if it is.

What is the con of not capping it off and having another port for more fresh air though? The flapper is long gone because it was stuck covering the "fresh air" port. I removed it and the heater hose to then have 2 ports to suck in fresh air. They've both been covered in netting to prevent large debris like leaves and such from freely getting sucked in.
 
What is the con of not capping it off and having another port for more fresh air though? The flapper is long gone because it was stuck covering the "fresh air" port. I removed it and the heater hose to then have 2 ports to suck in fresh air. They've both been covered in netting to prevent large debris like leaves and such from freely getting sucked in.

That's fine then. The only reason I suggested capping it was so you didn't suck in hot engine bay air.
 
You use the long preheater hose to turn forward to the front of the car. From the preheater hose ending run a pvc or piece of exhaust pipe through the hole for an air intake on that side of the car. Two cold air intakes. This example is on a 93 245. So the preheater hose comes from the bottom of the air box on the left side. Then goes under the fan shroud and turns forward to the hole in the right front sheet metal near the headlight. I used the stock air intake elbow for the pipe to go into at the front.
 
You use the long preheater hose to turn forward to the front of the car. From the preheater hose ending run a pvc or piece of exhaust pipe through the hole for an air intake on that side of the car. Two cold air intakes. This example is on a 93 245. So the preheater hose comes from the bottom of the air box on the left side. Then goes under the fan shroud and turns forward to the hole in the right front sheet metal near the headlight. I used the stock air intake elbow for the pipe to go into at the front.

I know it's been a while, but would you mind taking pictures of how your intake is setup? My preheater hose was way too mangeled to use again, but I'd be willing to buy another hose to route around to make some good cold air intakes.
 
I know it's been a while, but would you mind taking pictures of how your intake is setup? My preheater hose was way too mangeled to use again, but I'd be willing to buy another hose to route around to make some good cold air intakes.

If it?s mangled then just cap off the heater hose inlet at the airbox and mod the thermostat to only suck air in from in front of the condenser.
 
If it?s mangled then just cap off the heater hose inlet at the airbox and mod the thermostat to only suck air in from in front of the condenser.

Right now, both inlets are open with netting to prevent large debris from entering the airbox. It's been driving with with a little more pep in acceleration, but I'm just wondering about ways of getting colder air instead of sucking air from the engine bay. I already removed that restrictive 90 degree pipe with the small opening to feed more air into where the actual airbox inlet is, which helped a little as well.
 
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