So I recently upgraded to a Rancho Quicklift, rear spacer, and 33's and, over time, I've been able to tell a big difference in fuel mileage as well as power. I'm thinking of dropping in a bully dog tuner and a K&N filter in order to try and level it back out. Anyone with experience on this and any gains? Also, did I need to add an exhaust modification in order to balance out the increased in flow of air? I looked at the VQ40de's specs and couldn't find any backpressure reading in order to form an opinion. If so, I want to get a higher flow, but not change the sound of the engine. I'm not really a fan of V6's with pipes..

Any info helps,
Thomas

The intake spacer increased my midrange power and mileage a bit. Truck downshifts a lot less often on the uphills.

Several people here who've added heavy wheels and a lift are happy with the spacer.

ShipFixer wrote:The intake spacer increased my midrange power and mileage a bit. Truck downshifts a lot less often on the uphills.

Several people here who've added heavy wheels and a lift are happy with the spacer.

Ok, so I haven't looked to much into a spacer for the intake. Could you give me some info on those? I see what it does, I just don't get why and/or how haha. But also, would I be able to run a K&N with that and still benefit from both?

Extreme truck preformance intake manifold spacer. Best mod by far. And Gray is a hell of a nice guy to do business with

I did a k+n filter with the airbox mod from the titan/armada forums. You basically just open it up and shorten up the snorkel so as the air comes in, it disperses across the filter more broadly instead of just in one little corner

I also chopped the y-pipe and ran a magnaflow 12580 muffler. It's 2 in and 1 out and it definitely frees up the exhaust gasses. No backpressure issues to think about unless you are using huge pipes and huge headers.

A bully dog is a good investment too. Definitely my next mod for sure.

So what I'm actually looking for is the manifold spacer, not the small square shaped intake/throttle spacer? I figured a lot of K&N was just the cone shaped filter tho. Seems to just allow for more surface area to be used when taking in air. Could I just buy a filter and pvc pipe it to the intake hose? Jk but I'd do it if it worked! With your magnaflow, any changes there? Like gains and/or sound? I like the growl but I just can't get over the high end whine.

I think you're over-estimating how much increase in performance is gained by a K&N air filter install. You might get a small gain and primarily at high RPM, but not enough to necessitate changing the exhaust. Now that said, freeing up the exhaust will "usually" add some gain in performance in and of itself. But, like with the air filter, don't expect "huge" gains in power. Performance exhaust companies often taught gains of 35-50 hp or more, but you're not going to see that out of a VQ40DE unless you do a lot more work to the engine and programming.
The intake spacer makes the intake runners longer, which changes the power band. The stock intake runners have a pretty tight bend as they enter the lower intake manifold, so I could see where the spacer might be beneficial to the flow of air into the engine. The site for the spacer most of the forum uses is here:

http://extremetruckperformance.com/

As far as the gas mileage, bigger tires usually hurts gas mileage, especially if you do a lot of stop-and-go or city driving. Keep in mind that the change in tire size also affects your speedometer and odometer readings, something to keep in mind if you are computing your fuel mileage based on your odometer.

Funky_ChPimp wrote:So what I'm actually looking for is the manifold spacer, not the small square shaped intake/throttle spacer? I figured a lot of K&N was just the cone shaped filter tho. Seems to just allow for more surface area to be used when taking in air. Could I just buy a filter and pvc pipe it to the intake hose? Jk but I'd do it if it worked! With your magnaflow, any changes there? Like gains and/or sound? I like the growl but I just can't get over the high end whine.

yes. the intake manifold spacer. www.extremetruckperformance.com

not a throttle body spacer. those things are worthless.

our trucks have a sealed cold air intake which draws air from the bumper. there are a few aftermarket ones that are sealed as well. a cone filter and pvc pipe wouldn't be a cold air intake anymore. you'd be drawing hot air form the engine bay.

with the magnaflow, virtually no changes at idle and when coasting along. beautiful growl as it goes through the power band. no high end whine. then again, how high are you taking your rpms in a lifted truck. it's not a dragster, it's a truck/suv. I mean, I wind it out when I get on the highway sometimes, but it doesn't whine at all .

smj said it best. you shouldn't expect "huge" gains in power from these mods, but the are noticeable with the butt dyno test. the power band change from the intake manifold spacer makes the truck, particularly once lifted with larger tires, far more driveable. you get more low end response. which is what you need in a heavy lifted truck.

I always calculate my mileage and factor for the increase in tire size. like I posted in another thread, I went from 18mpg to 15mpg with the lift and tires. I got 2mpg back with the mods I did. so I am right around 17mpg as a daily driver on country/county roads. hard to complain about that

i have both the K&N and Bullydog. I think I might have gotten .5 mpg IF any.

Intake sounds good, that's about it.

Excellent info guys. I am expecting gains from $600 worth of mods, maybe not better than stock mpg's and power, but just a noticable difference. I think I'll go with the bully dog and an intake spacer, hold off on the K&N. The way I look at it now, my engine just has to compensate for added weight and can't do so with the stock computer running things, thinking it has a stock load on it. I know I have the power to turn the tires, so really all I need is something to adjust my engine's timing in order to allow it to fire in an order that effectively and more efficiently turns them. I dont think adding a K&N allows for more combustable air to enter the block, just gives less restriction in bringing it in, which sounds like it could even harm my mpg's. I do have a pretty heavy foot so allowing my engine to just pop up to a high rpm at any time might not be exactly what I'm looking for.

sounds like a good plan. the spacer and bullydog are 2 great mods.

fyi, here's a link to the titan airbox mod. it's simple stuff. that combined with a k+N drop in filter should yield you just about all the intake gains that any other aftermarket intake could possibly give you and the drop-in is like $50

http://www.titantalk.com/forums/titan-p ... x-mod.html

not on the rug wrote: fyi, here's a link to the titan airbox mod. it's simple stuff.

I mentioned this one in another post a couple of years ago, but related to info I found on one of the Xterra sites. So far, the only benefit I've read about is a louder engine noise from under the hood. I've seen people post until they were blue in the face trying to argue for the mod or against. Many stupid theories out there on the forum, but absolutely no facts or proof of anything. I'm still planning on doing this as I have one of the intake tubes on hand as a spare (foam was shredded on my previous one). All I expect is more noise, preferably a deeper growl. Most people equate that to meaning more power, but it's all a mental thing.

NVSteve wrote:

not on the rug wrote: fyi, here's a link to the titan airbox mod. it's simple stuff.

I mentioned this one in another post a couple of years ago, but related to info I found on one of the Xterra sites. So far, the only benefit I've read about is a louder engine noise from under the hood. I've seen people post until they were blue in the face trying to argue for the mod or against. Many stupid theories out there on the forum, but absolutely no facts or proof of anything. I'm still planning on doing this as I have one of the intake tubes on hand as a spare (foam was shredded on my previous one). All I expect is more noise, preferably a deeper growl. Most people equate that to meaning more power, but it's all a mental thing.

Hard to say what it actually did because it's not like I only did that mod and then dyno'd the pathy. From the pics I've seen posted, it does seemingly help the air disperse in the airbox better as evidenced by a mostly dirty air filter as opposed to an air filter that was only dirty in the corner. Now what does that mean exactly? Who knows...the way I looked at it was that it can't hurt to do it, so why not? Ya know?