1973 C10 "The Purple Truck"

[ZooMad75]

I went back to factory TBI style air cleaner. Still had a little whistle with the cold air type setup and after seeing the decrease in air inlet temp, I'd rather put the cold air setup on the crew cab.

View attachment 365634

Bearing in mind the weather temps have been around 40°, here's the air inlet temps:

• Cold air type: 55°
• Factory TBI type: 100°
• Open element type: 136°

The core support in the 73 doesn't have an opening for the TBI tube so it isn't getting direct outside air, but neither was the cold air style. Also the air temp sensor on the TBI setup ended up being on the opposite side from the air tube, so it might read cooler if it was closer to the air coming in.

This is interesting. I was watching my intake air temps on Torque while I drove home from Denver. Consistently as long as the truck was moving at 20mph or better I was seeing 20-25° higher temp than ambient for the intake air temp. That's with the open cone air filter directly behind the core support with the 4" hole in it. If I came to a stop the IAT climbed to 100-105° with the ambient temp at 35°. I can only imagine what the split is when the ambient temp is 80-100° in the summer. Just doing some googlefu on the subject comes up with for every 10° change in IAT it equals a 1% change in horsepower in either direction. That means I was seeing as much as a 7% drop in power. In your case, you were leaving a little over 9% on the table with the open-element vs 1.5% with the cold air intake. That is provided that the 10°/1% rule of thumb is accurate for a naturally aspirated engine.

It certainly makes looking at an effective cold air intake a worthwhile addition to maximizing power and economy.

 

[folkenheath]

In other news, I seemed determined to make the ECU on the PF4 not work. The truck was idling in park and the coolant kept getting hotter and the fans weren't coming on. Shut it off at 210°.

Popped the hood open to test the fan controller. I inadvertently bumped the ground wire and the fans came on for a second. Wiggled the ground and the fans came in again. Found the nut on the ground post loose.

The ground for the PF4 is on the same post! A couple of times recently the tablet has randomly disconnected from the PF4, but haven't noticed any other glitch, tho. Glad I caught it when it was convenient.

I would most definitely hook your ECU ground up directly to the battery, even a solid ground to the chassis can still create ground loop noise and voltage fluctuations that can cause issues with engine running correctly and reliability issues. If you don't have your ECU power and ground directly to the battery terminals, I would fix that as soon as you have time. I have seen this cause issues on many occasions.

 

[mrk5]

This is interesting. I was watching my intake air temps on Torque while I drove home from Denver. Consistently as long as the truck was moving at 20mph or better I was seeing 20-25° higher temp than ambient for the intake air temp. That's with the open cone air filter directly behind the core support with the 4" hole in it. If I came to a stop the IAT climbed to 100-105° with the ambient temp at 35°. I can only imagine what the split is when the ambient temp is 80-100° in the summer. Just doing some googlefu on the subject comes up with for every 10° change in IAT it equals a 1% change in horsepower in either direction. That means I was seeing as much as a 7% drop in power. In your case, you were leaving a little over 9% on the table with the open-element vs 1.5% with the cold air intake. That is provided that the 10°/1% rule of thumb is accurate for a naturally aspirated engine.

It certainly makes looking at an effective cold air intake a worthwhile addition to maximizing power and economy.

Funny, we're cross posting in each others' threads about this. I just posted my temperature numbers in your thread. I also expressed my doubt about the difference in power numbers in your thread so it's funny you posted the power numbers in my thread. I believe the horsepower percentage numbers above might be correct, but I'll bet those are wide open throttle numbers. I bet the percentages might be smaller for lower throttle positions. Also like you mention, boosted vs n/a. I've mentioned before that Engine Masters did some dyno pulls testing different air intake temps and they inadvertently found that it was the fuel temperature that made the most difference. This was on a n/a engine, but also at WOT.

Plus I have a wimpy stock motor so 9% of 100hp isn't as big of a deal as 9% of 500hp. Haha!

 

[mrk5]

I would most definitely hook your ECU ground up directly to the battery, even a solid ground to the chassis can still create ground loop noise and voltage fluctuations that can cause issues with engine running correctly and reliability issues. If you don't have your ECU power and ground directly to the battery terminals, I would fix that as soon as you have time. I have seen this cause issues on many occasions.

They are basically direct to battery. These are the terminal ends I used.







The "new" locknut can be seen on the negative terminal. Previously I just had a nut and flat washer, which never loosened up on me before. Makes me question whether I remembered to tighten the nut when I installed the PF4.

 

[mrk5]

Yes, my battery is zip-tied in place. Previous owner welded angle to the battery tray, I assume to fix a corroded tray. He didn't make provisions for a battery hold down. So when I got the truck the batter wasn't held in with anything. I've found replacement trays for about $25 online, but I haven't pulled the trigger yet.

 

[Capt Ron]

Next time you are in the area stop by. I have a few pass side battery trays.

 

[folkenheath]

They are basically direct to battery. These are the terminal ends I used.

Ah, I see, carry on. I thought you had them on a stud on the frame or something. That looks fine.

 

[mrk5]

Ah, I see, carry on. I thought you had them on a stud on the frame or something. That looks fine.

I do want to add a cable from the battery to the frame. Right now it's just a smaller guage wire, maybe 12ga. Just thinking at the very least I have added an electric fuel pump thats grounded to the frame. That alone is a pretty big jump from what the factory grounded to the frame.

 

[mrk5]

Easy fixes are nice to find.

Especially when they are caught before stranding you on the side of the road.

 

[ktmoutfront]

Especially when they are caught before stranding you on the side of the road.

Or burning your battery down in the middle of nowhere.

 

[ZooMad75]

Kid that lived next door to me when I was young had a battery held down with a bungee cord in his '66 C10. Went around a long sweeping right hand curve and the cord broke allowing the battery to get cozy with the 4 blade solid fan with no clutch on it. Shredded the battery and coated everything under the hood with battery acid.

Crazy thing, he still drove it home 5 miles with what was left of the battery pulled out of the fan.

It was a hell of a mess to clean up too. Lots of baking soda.

 

[ashman]

Kid that lived next door to me when I was young had a battery held down with a bungee cord in his '66 C10. Went around a long sweeping right hand curve and the cord broke allowing the battery to get cozy with the 4 blade solid fan with no clutch on it. Shredded the battery and coated everything under the hood with battery acid.

Crazy thing, he still drove it home 5 miles with what was left of the battery pulled out of the fan.

It was a hell of a mess to clean up too. Lots of baking soda.

I had the same thing happen to me in Moab years ago. Battery held down with a bungie cord, got to bouncing over some rocks and right into the fan. Luckily the hole it made wasn't huge so I was able to drive it back to town. Still made quite the mess.

 

[centexk5]

Battery hold down broke on a hill climb and bounced the battery in to the exhaust manifold one time. That was fun.

 

[mrk5]

See, this is why I went with a 1/4" wide zip-tie. No bungie cords.

 

[Truckman4life]

I prefer to use a ratchet strap around the tray and battery. Works awesome! i think the one I have now is the kind for going around something and back through itself.

 

[mrk5]

I prefer to use a ratchet strap around the tray and battery. Works awesome! i think the one I have now is the kind for going around something and back through itself.

I thought that if I used a ratchet strap I would go longer without fixing it. I thought that if I used a zip tie, I would fix it sooner. So far the logic isn't holding though...

 

[Truckman4life]

I thought that if I used a ratchet strap I would go longer without fixing it. I thought that if I used a zip tie, I would fix it sooner. So far the logic isn't holding though...

LOL my ratchet strap has been doing great for like 3+ years. I also trust it in a rollover vs a zip tie. We do have some gigantic 3' long 1/2" wide zip ties at work though.

 

[ashman]

I thought that if I used a ratchet strap I would go longer without fixing it. I thought that if I used a zip tie, I would fix it sooner. So far the logic isn't holding though...

I've been known to use that logic a time or two myself... with similar results.

 

[AJMBLAZER]

The cord on my bench grinder is wire nut’d together and wrapped with electrical tape. I did that in about 2004 to get me by when I needed it one day and I’ve never bother to fix it correctly.

 

[folkenheath]

"it's only temporary..........................unless it works."

Disclaimer: That is not my motto