RockyMtnTitan
08-21-2005, 12:03 AM
I was all set to do the JetTech Coolant Bypass mod the other day, when I had a thought.....why not just install a small ball valve instead so that you could heat the TB during cold weather if needed, and then close it for warmer weather to reduce intake temps. BTW, JT, you're famous once more! That is, when I googled "coolant bypass" a link to your pixaggo page with all your truck photos came up!
The problem was trying to find a very small ball valve for the application. I went with a 1/4" brass-bodied valve I found in the air compressor accessories section at Lowes. Just install a couple of 1/4" npt X 5/16" barb adapters to each end. Other than that, all you need is about a foot of 5/16" id fuel/heater hose and 4 clamps. Install is straight forward, as you can hopefully see in the pics I've attached.
Intake Temperature Testing:
I did some bef/aft temp testing, measuring intake air temp rise across the TB to see how much this mod reduces the intake temp. I used a fairly accurate and fast acting Fluke 52, dual input digital thermocouple. Here's a few numbers to digest. Let me know what you all think.
Before: (Motor at operating temp)
Ambient Temp= 85 deg F
Temp Rise across TB after idling for 5 min = 17 deg.
Temp Rise across TB cruising @ 70mph/3300rpm/3rd gr = 7 deg
Temp Rise across TB during 0-90 run @ WOT:
Start = 15 deg rise
60 mph = 2 deg rise
90 mph = 1 deg rise
After: (Motor at operating temp)
Ambient Temp= 87 deg F
Temp Rise across TB after idling for 5 min = 5 deg.
Temp Rise across TB cruising @ 70mph/3300rpm/3rd gr = 4 deg
Temp Rise across TB during 0-90 run @ WOT:
Start = 6 deg rise
60 mph = 1 deg rise
90 mph =.5 deg rise
As you can see, the biggest benefit of this mod is the reduction of intake temp at idle. The temp rise @ WOT was minimal both before and after mod, which makes sense. The air is moving too fast for much heat transfer to take place. But think about all that heat sitting inside the intake plenum at idle....seems like a real low-end torque killer to me. So by taking that 17 deg rise down to about 5 deg has gotta help.
Of special note, I found that the intake temp measured in the tube just before the TB inlet would reach temps as high as 134 deg! Keep in mind this is with an ambient of 85 deg, a Volant CAI, and with the TB coolant valve off. It appears that the plastic intake tube gets heat soaked from the radiator and a/c fan (if on) discharging a lot of heat across the tube, as it is directly in the flow path. This temp does not cool down instantly after opening the throttle (other than wot). It took several minutes of driving around to see the temp come down. I know thick-walled plastic is a pretty good insulator, but in the event it does get heat soaked, it takes a while to lose that heat. Aluminum, though, would probably heat up quicker (and more), but would dissapate quicker. I may try to insulate the tube, if I can find something that looks good....cuz that's important...lol!
Sorry for the long post...hopefully someone else finds this stuff as interesting as I do.
The problem was trying to find a very small ball valve for the application. I went with a 1/4" brass-bodied valve I found in the air compressor accessories section at Lowes. Just install a couple of 1/4" npt X 5/16" barb adapters to each end. Other than that, all you need is about a foot of 5/16" id fuel/heater hose and 4 clamps. Install is straight forward, as you can hopefully see in the pics I've attached.
Intake Temperature Testing:
I did some bef/aft temp testing, measuring intake air temp rise across the TB to see how much this mod reduces the intake temp. I used a fairly accurate and fast acting Fluke 52, dual input digital thermocouple. Here's a few numbers to digest. Let me know what you all think.
Before: (Motor at operating temp)
Ambient Temp= 85 deg F
Temp Rise across TB after idling for 5 min = 17 deg.
Temp Rise across TB cruising @ 70mph/3300rpm/3rd gr = 7 deg
Temp Rise across TB during 0-90 run @ WOT:
Start = 15 deg rise
60 mph = 2 deg rise
90 mph = 1 deg rise
After: (Motor at operating temp)
Ambient Temp= 87 deg F
Temp Rise across TB after idling for 5 min = 5 deg.
Temp Rise across TB cruising @ 70mph/3300rpm/3rd gr = 4 deg
Temp Rise across TB during 0-90 run @ WOT:
Start = 6 deg rise
60 mph = 1 deg rise
90 mph =.5 deg rise
As you can see, the biggest benefit of this mod is the reduction of intake temp at idle. The temp rise @ WOT was minimal both before and after mod, which makes sense. The air is moving too fast for much heat transfer to take place. But think about all that heat sitting inside the intake plenum at idle....seems like a real low-end torque killer to me. So by taking that 17 deg rise down to about 5 deg has gotta help.
Of special note, I found that the intake temp measured in the tube just before the TB inlet would reach temps as high as 134 deg! Keep in mind this is with an ambient of 85 deg, a Volant CAI, and with the TB coolant valve off. It appears that the plastic intake tube gets heat soaked from the radiator and a/c fan (if on) discharging a lot of heat across the tube, as it is directly in the flow path. This temp does not cool down instantly after opening the throttle (other than wot). It took several minutes of driving around to see the temp come down. I know thick-walled plastic is a pretty good insulator, but in the event it does get heat soaked, it takes a while to lose that heat. Aluminum, though, would probably heat up quicker (and more), but would dissapate quicker. I may try to insulate the tube, if I can find something that looks good....cuz that's important...lol!
Sorry for the long post...hopefully someone else finds this stuff as interesting as I do.