Texas_Ace

Like I said I could not believe it either so I ran the test twice.

With the stock box ALLL the air comes from the fender. With an aftermarket intake there are all sorts of holes and cracks that allow air to come from the engine bay. Plus the big hole behind the headlight that gets some of the hot air from the radiator ect. The thin metal heat shield is also not all that great, it transfers heat real well vs plastic like the stock airbox.

Not to mention like I said, even in a perfect world the aftermarket intake is not going to improve on the stock design, there is nothing to really be improved on. Filter is plenty big, piping is also properly sized, no harsh bends, no restrictions and pulls ALL of it's air from the fender. Where are they going to improve on the design?

2ShotTuck

Well if I do what I was thinking, only expand on the idea and improve the heat shield for the filter, it may do better

Texas_Ace

No, the aftermarket intake starts at a loss, the best you can hope for is to match the stocker. Sorry but just the way it is. These same results were found by URD which is why they do not offer an intake for the 5vz but they do most others.

2ShotTuck

10-4 rubber ducky, thanks for the info. Like I said ill stick with it until I find out its a problem causer, till then I'm happy with it.

2ShotTuck

Hey Texas, do you know anything about aftermarket headers? Recomendations?

Texas_Ace

Yeah, I got them on my truck. Not worth the money or time (NIGHTMARE to install) for an NA truck IMO, only ~10-15hp for ~$1500+. You can get a supercharger for that price and have an extra 75hp.

2ShotTuck

Alright, I was going to do the install with a friend in his garage. Throw him a 6 pack of good beer and a couple cigars, call it even. You probably figured I'd ask, but any notice in fuel economy?

Texas_Ace

You have NO idea what you are getting into with a header install. It took me a full 3 days to get mine installed, most of that time was spent on the drivers side stock manifold, that thing will not come off, you can not get a socket/wrench on most of the bolts and if you do they usually just round off.

Seriously, don't waste your time, spend the money on a supercharger. You will get 10x the effects and it will be WAY more fun.

I can not emphasize enough how pointless it is to try to get power out of a 5vz while NA. I am NA right now with every power mod you can do, it is hardly any faster then stock. The most noticeable difference is the high stall converter, that was worth the money. I would take a bone stock motor in every other way with a supercharger bolted on, stock pulley and all over all the NA mods you could do. It will be a lot cheaper too.

Between the SC and the headers yes I saw an improvement in MPG, about +2mpg or so.

Dirt Driver

It occurred to me that a "hot air" intake could possibly improve fuel economy. I'm thinking that the hotter air will reduce power at any given throttle opening, therefore requiring the throttle to be open more during normal driving. This reduces pumping losses and tends to reduce brake specific fuel consumption.

A TB spacer just increases plenum volume by a very small amount, which isn't bad, but won't show any gain on the butt dyno. The swirly grooves that some have on the inside are simply a gimmick.

What are the rest of the specs on your truck?

2ShotTuck

Oh I know its gunna be a Bitch, I read about installs trying to find the info you just told me, I planned on cutting the crossover pipe, pulling the motor, and removing the the stock ones, placing the aftermarkets while on the stand, ever so carefully dropping the motor back in and then installing the aftermarket cross over. It's a lot of work but a lot less headache. In my mind at least.

2ShotTuck

Nothing spectacular. I bought the truck with the lift, its either pro comp or fabtech. A cat back flowmaster 2.5" exhaust with 40 series muffler & dual outlet, spectre cold ( hot) air intake, airaid throttlebody spacer. Wanting the magnaflow cats, Jba headers, spray in bed liner,complete audio overhaul, and when I can aford it, supercharged. It's a good rig, does need some love in the interior. dash rattles, ac rattles, door pannels are falling off and passenger seat just busted. Would like to re-do the paint. She's 12 years old and has her scratches and a few minor dings.

Dirt Driver

I meant factory specs that have a bearing on fuel economy. Is it a 2wd, 4wd, or PreRunner? 5-speed or automatic? Tire size and type?

Texas_Ace

I see where you are coming from but sadly that is not how it works. The pumping losses would be less yes but you would be injecting more fuel to maintain/accelerate the same. So the net result is a loss of MPG.

Now a factor for hotter air that would be more likely to improve efficiency would be the fact that the hotter air will help the fuel atomize better which leads to a more complete burn and thus better BSFC.

Although this also does not work in the real world, it is used commonly on alcohol powered cars though since it is very hard to get the fuel to fully atomize. So they will not run intercoolers and raise the compression to help the fuel atomize.

In the real world making more power easier will generally net you the better MPG. For example most see an improvement in MPG when adding a supercharger or turbo.

You are right on the TB spacer as well.

No need to cut the crossover pipe, particularly if pulling the motor. I was able to get mine to drop out without cutting it no problem, just takes some wiggling and a jack.

With the motor out the install will not be hard but that is a lot of work when bolting on a supercharger will net you better performance in every way by a LONG shot. More reliable as well since header like to crack/come loose. Took me a few years to finally get my headers to stay sealed up.

If you are determined to waste your money on the most inefficient power mods (or very efficient power losses as the case may be) and pull the motor. Then you should get yourself a high stall converter for the transmission while the motor is out. That will make the single biggest change in how the truck feels to drive.

When my truck was supercharged in AWD mode I could launch from a stop and it would just kind of go till around ~3500rpm and then it would take off. After getting a high stall converter I would chirp all 4 tires on the launch and it would TAKE OFF. I was pulling a 2.0 60ft on the street in a 4700lb+ truck!

Boost is the ONLY way to get any kind of reasonable power gains that you can really notice on these motors. Why are you so against it?

2ShotTuck

Oh I gotcha, 4x4 trd off road, 31-10 1/2 bf mud terains... Automatic (sigh)

2ShotTuck

Ha I'm not against boost at all, I was considering a turbo for a while then lost interest in it after thinking about turbo lag, and how much more work would go into it. I considered nos just for the great gains it gives for the little work that needs done, and then realized I'd be dumping more fuel in and that's the opposite direction I'm going. Like I said a few minutes ago supercharged is a direction I'd like to go, but financially, just buying $750 headers would be almost 1 year down the line.

Texas_Ace

If you have a year to look around you can find a supercharger for that same $750. Heck I got mine for $300 and then rebuilt it for another $300.

Also turbo lag is WAY WAY overblown. Properly size a turbo and you wont have any lag, particularly on an automatic transmission you can set it up so you have no lag at all.

Check out some threads by clownmeat, he built his own turbo kit that works good and is cheap if you can fab up some basic parts yourself. This will give you more performance then a supercharger at the cost of being more complicated.

Lastly you can't have your cake and eat it too, if you want more power then you will be injecting more fuel, this is the way of life.

But you are only injecting that extra fuel when you are using the power, driven in the same exact manner (same speeds, same acceleration rate ect) the boosted engine should get a little better MPG.

Even when going WOT, a higher powered car only needs to be WOT for lets say ~20 seconds to reach 100mph but a lower powered car will need to be WOT for say 40 seconds.

So even though you are injecting more fuel in the higher powered engine you are not staying WOT for as long so your net result is less overall fuel being used to reach the same speed.

Really though, your driving habits will determine your MPG more then everything else put together. I can get as low as 8mpg when tuning a car (aka, constantly going WOT), that same car driven like grandma will get mid-low 30's mpg.

2ShotTuck

How in the hell did you find one for less than a grand? You must live in bigger area than me

Texas_Ace

I have seen them go for under a grand all the time. Heck I have had the chance to buy more then a few for $500.

Just got to keep an eye out and watch for them to pop up for sale. Where you live doesn't matter, mine came from someplace up north.

Watch ebay, the various boards, Craigslist ect. If you have a year to find one something will pop up. Saw a few go on ebay just a few months ago for less then a grand (never really check, just checked once and saw a few closed listings).

2ShotTuck

Yeah, locally here tho, you never find anything other than a 350 and some straight axles, and I'm not about that for this rig

Texas_Ace

Screw local, even around me you never see them pop up at all much less for a good deal. Ebay is where I have seen the most consistent good deals although they do pop up on the boards regularly as well. Just got to keep an eye out.