Cam gears for V6. Add power AND mpg

I’m about 700 miles in to the cam gears. I think I’ve gotten about .5 and mpg better but I’m still at 13.9 MPG average so far, after zeroing the average. Some of those 700 were dirt miles so that dropped the average, but before the dirt I was running about 14.4 mpg. I think I’m going to need the tune to get more performance out of it. As it stands, applying throttle, it seems the ecu just wants to throw fuel at it with no in-between.

Question though, what octane fuel are you guys running? When I bought the truck I was getting some fuel knock in hot weather, so I started running 91 and that took care of it. But I’m not sure if it’s still necessary or having any meaningful value since the change.

 

Thanks for your review man. I bet that half mpg will go up more when dirt roads aren't in play. As for your gas choices-
If you're not forced induction- you should be able to switch back to 87 octane without getting knock in the hot weather. Remember the gears hold the exhaust valve open longer so more hot exhaust gas is pushed out the chamber. Now you have less hot exhaust gases heating you're incoming air. This is why we see an increase in knock threshold when these gears are installed.

 

Been running 87 w/ no issues. Sticking with it.

 

Cool beans. Next tank I’ll try stepping it down and see how it runs.

 

Checking the service history on my truck, it looks like they did the 20TC01 Recall work. Does this mean I am air pump issue-free?

Name - Part #
REPAIR KIT, AIR PUMP - 040083520C
KIT, VALVE ASSY, AIR - 0400834131
COVER, AIR PUMP - 176130P010

 

I had to look into what was involved with that recall. But it looks like you should be good. The new filter shouldn't break down which is what causes the issue

 

To follow up on the efficiency increase, I looked back at my fuel logs from my road trip in the fall and compared it to my most recent fill-ups. Falling right in line w/ other's experiences; On average a 1.5 mpg increase.

 

Gears installed biggest difference I feel off the bat is down shifting doesn’t lurch me forward and I seem to coast longer. Not sure on mileage yet reflashed with battery disconnect. I have an X-runner so 6sp Manual, I assume most have the auto in this thread.

 

Just ordered a 3rd set!

 

6 speed here

 

@nd4spdbh
any further thoughts yet on keeping vs ditching the intake manifold spacer when installing these gears?

 

I have not had the time to dedicate to getting a good log (in easily repeatable weather conditions) then pull it and get another log (i really wanna see how maf numbers are effected by the IMS).

It is still on my radar to do!

 

waiting on this is one of the excuses I've been using for not installing yet lol... this, recovering from an injury, trepidation and pure laziness

 

I chose to leave mine on, as you might've seen from my install post. There's dyno sheets showing the gains from the manifold spacer and we see maf numbers for the gears. Both show improvements. But since they're different parts of the wheelhouse, shouldnt they provide those gains irrespective of each other? On one hand we're talking intake volume, the other, exhaust scavenging. No?

 

Correct. Paired together they will both provide a boost.

My thought process from my perspective was from and MPG stand point. You have cam gears creating a more efficient motor (via increased time for gases to burn) which should in theory provide more MPGs (and seems to have been proven to do so). The intake manifold spacer on the other hand while it creates a more powerful motor (which might help to put the motor in a more efficient operating range) it does so by increasing air flow... more air in = more fuel needs to be burnt.

When i put the cam gears in i slightly tore the paper gasket of the IMS, i got it back together and sealed it well so there are no vacuum leaks, but it hasnt sat well with me. So i figured for science, pull off the IMS (and poke my head under valve covers to verify tightness of cam bolts cus im anal like that), run it without the IMS for a cunk of time to see how i like it while i acquire a new paper gasket. And go from there.

 

Does anybody know how to tell if you screwed up installing these gears? I recently installed cam gears when i rebuilt my supercharger and have been getting black soot at startup. The exhaust note sounds louder also. I can't think of any other reason the truck would have these symptoms, but id like a little more idea before I go back in there.

 

Gotcha. Thought it was more of a question of hp/tq increase/curve than mpg's. I'd be curious to see numbers if you do it tho.

 

Did you change ANYTHING else at the time, like a new tune?
Having the battery disconnected will cause the ECU to relearn, so maybe it is even more rich than before.

 

Do you have any pictures of them right after installing them showing the alignment to the timing marks? Short of that, the only other way to really install them wrong would be upside down or backwards, I suppose.