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Another my MPGs such thread


deerhurst
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Hey guys, anyone else running a VG33 with TBI? I've got a VG33 running TBI in my 86.5 Hardbody. Its a single cab short box 4wd on 31s and a 4.1:1 rear end and long tube headers. I'm currently at about 18 degrees BTDC of timing which made it come alive. I was hoping for similar MPGs to my old 3.0 which was getting 16-17MPG on 5 cylinders and up to 25MPG on the open highway when healthy.

 

At 12degrees BTDC I was getting 15.6MPG and the VG33 was a dog.

 

At 15degrees BTDC I was getting 14MPG and it started to wake up.

 

Currently at about 18degrees BTDC and its running great. Seems like the valve train it a little loud when cold though. I'm getting about 16MPG and close to 17MPG on the open highway. Any suggestions for an MPG or two? I'd love to be back at 20MPG but right now even 18MPG would be nice.

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I'm not sure what all you have done, but have you made sure the o2 sensor is in good shape? It made a big difference on my wd21 and my 3.3L xterra. The TBI probably can't regulate fuel as well as the newer injected models.

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I have mostly been playing with timing. The old motor did fail with a cracked piston and was pressurizing oil into the air filter assembly. I wouldn't be surprised if that took out the O2 sensor. Only other new sensor is the cyl head temp sensor that bolts into the driver side head. The rest is all factory from 4/86.

 

I talked to a guy at Jim Wolf Technologies yesterday and he said O2 sensor as well and have me some ideas for making more power. He said with how old the sensor is he would just replace it anyways. I plan to replace it later this week. Gotta source one first.

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Let us know what the difference is. Also just curious, how did the swap go? Does sticking with the TBI make it a lot more straightforward?

 

25mpg seems incredible, how fast would you drive to get that?

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+1 on checking that O2 sensor. My Pathy used to get upwards of 20-22MPG on the highway until my O2 sensor started to crap out. Caused it to stutter, run rich when idling at stop lights, the whole nine yards. Swapped it and all those issues are gone and I'm getting roughly 18MPG again. Good luck!

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Yeah, I can easily get 24mpg in my stock 95. Last year my brother and I drove it from Ontario Canada all the way to the west coast and back. It was averaging 20-25mpg the whole time. Ran flawlessly.

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Let us know what the difference is. Also just curious, how did the swap go? Does sticking with the TBI make it a lot more straightforward?

 

25mpg seems incredible, how fast would you drive to get that?

Swap was stupid simple once the details were worked out. My motor is a JDM motor converted to use Xterra/Frontier spec accessories and belts. It was pathfinder configuration. It all just plops in there. The VG33 doesn't have the head temp sensor in the driver side head and I think that's all I had to add. Used VG30 plenum gaskets too. Ive got a 6 puck ceramic clutch, long tubes and a vacuum delete going on in there. A lot more power than the old VG30i.

 

I drive 65-70MPH. I have a HG41 rear end and its a single cab short box 4wd Hardbody so its a little lighter than a pathy. Was getting 17MPG as my old motor was finishing giving up the ghost and choking on oil.

 

Just got the sensor replaced yesterday. Got a whole maybe 5 miles on it so far.

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Starter crapped out on me after only 3 years. Replacing that today. Still have yet to get through a full tank. Gotta do the first oil change on my new motor too.

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  • 2 weeks later...

So, still sitting around 16ish MPG. Got 15.7MPG doing a little "light" towing (a small flatbed trailer and about 800lbs of cargo) and some gnarly head winds to go along with our crap weather around here.

 

So, Im guessing the old one was good. Glad I saved it.

 

Any ideas?

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  • 2 weeks later...

Still around the same. Bumped timing up to about 22BTDC ish. Tried to lug it around a bit to find issues and found none. Gonna do a couple tanks at this timing. Cant believe Im getting 10 more degrees out of it than the stock VG30i is recommended to run.

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I haven’t done any mileage tests yet to confirm this, but I’m definitely getting significantly better gas mileage with my tires at 38psi. They were at 25psi per the chalk test and it was like having the brakes depressed slightly all the time.

 

Many times I could just let off the gas at a reasonable distance before a turn and I barely had to hit the brakes to make the turn...

 

Also the howl, which I liked at first but is a nuisance, is muuuuuuch quieter!

 

I was getting 13.5-14.5 miles per gallon before and I bet I’m getting 16 now. We’ll see though..

 

 

Sent from my iPhone using Tapatalk

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