aviator

Don't you start now taco

Tacoclimber

I couldn't help it. After you've been around this place as long as we have, these kinds of threads start getting boring. I was just trying to make it interesting again.


Before you know it, we'll see another K&N/similar filters vs. OEM filters thread.

Teuf

Oh man here we go again.

Blacktoy

Sorry to bump a 2 month old topic, but I found this page http://www.gadgetonline.com/AirInduction.htm

This is someone who has done the deckplate mod and ran it on the dyno with an increase from the mod. What I am interested in is removing the air elbow. Any support on this?

Blacktoy

Nevermind, I found a step by step process: http://www.4runners.org/writeups/airbox/index.html

cackalak han

I recently did the catplate mod. Punched a big hole in my cat. Awesome.
Also swapped out the rhodium and platinum for the much lighter titanium. Well worth it.

Parker Runner

You will lose some ability if you plan to ford deeper streams. The purpose of the deckplate is to retain the ability to reseal the airbox for fording.

bgmac

Apparently you missed this on the first page!

ESQ

Back to how you measured the pressure... You have to use a pitot tube perpendicular to the flow to measure the static pressure and you have to take a number of measurements across the flow to get enough data to be significant. Otherwise you will get dynamic effects (i.e. velocity head) and the readings won't mean much. Velocity head could cancel any static vacuum and make it appear that there is around zero vacuum.

Measurements must be done correctly in a repeatable and controlled fashion with equipment properly calibrated and sensitive enough to the pressure differences in the range that you are expecting.

That said, I haven't dynoed my deckplate modded engine, but I do feel a difference at 3k rpm plus and this is supported by some dyno measurements that others have taken. Remember also, that this is world vehicle, and not just for the NA market. The Hilux surf is marketed around the world.

kawicowboy

Last year I had a 96 LTD 3.4 that had been in a front end collision, so it did not have a airbox at all just a cheap cone filter, I sold it and bought a 97 LTD completely stock accept for the ISR mod. That 96 with the open filter ran better, was quicker, better passing gear and had way better milliage than the stock 97. I believe the open filter made all the difference.
Just my 2cents

aviator31

Well, I don't think you are a English major, that's for sure. J/K around. I appreciate all of your thorough research and insight, but why is this discussion such a big deal? Why don't we just let people do whatever they want to do and leave it at that? It isn't like anyone on here is making a bunch of money off of this modification or ripping people off. I think this modification is akin to putting a baseball card in my bike spokes when I was a kid. That made ME feel like I was going faster, so what was the harm? Maybe it is just our human nature to always try to prove that we know more than everybody else...

DailyDrive

It is not a big deal, it's a discussion board, for discussing things.
We discuss problems, issues, concerns, and improvement to our vehicles. When someone starts doing "rain dances" to improve gas mileage, and tell everyone that it works, then I think it's worthy to discuss the merits of such practices, while keeping the discussion within the bounds of modern science and scientific methods.

okie81

I gotta look into that! Not only does it sound like major HP increases, but if you sold the metals, you could even MAKE money on that mod

So far the window decal mod and the high performance camper shell mod haven't panned out very well for me.

TacoFitz

You only rev'ed the engine to 4000 rpms... you didn't exceed the flow capacity of the stock intake. If you were to spin the engine higher more air would be required, and the stock hole area would choke the engine vs the modded intake.

DailyDrive

No way!

But realistically, unless you are at the drag strip making everyone jealous with the 3.4, there is no reason to rev it above mid 3000s where the torque peaks.

Just like most people don't need ZR tires to go over 200mph, they don't need to hit the redline while driving. I certainly haven't had the need to do that in 10 years of owning the 3.4. Maybe that's why I haven't ever started a "Where can I buy an engine cheap?" type of thread.

txrider

Sure there is, it's not all about where your RPM's are and where you are in the torque curve at the moment, it is also very much about what your RPM's will be and where you will be in the torque curve after you shift.

If shifting at 3000 RPM in second, will put you at an RPM that has less torque than you get at 4000, you're better off reving on up to 3700.

As for intakes, cars have to pass ever more stringent sound tests these days, and they are getting stricter on intake noise as the years go by. It's not all about what a soccer mom might or might not like.

That said any gain that night be had by opening the air box ahead of the filter is going to small, as in likely not measurable. Unless you do other modes to open air flow up significantly above stock elsewhere. Certainly not enough gain for me to start changing anything on mine.

RELLIM

A larger intake box with a 3.5 intake hole will get you better results than a large hole in a small oem box. Atmospheric air, depending on the density up to something like 14 psi pushes into the air box where the engine pulls it in. At wot there is no atmospheric pressure in the intake tube, the engine vacuum takes over. As the butterfly closes atmospheric air pressure rises. When u draw air from a closed box system you create a higher velocity of air going to the engine. It would help fill your cylinder fill.

As for your Resonator, it works in two ways. The resonator is a tuning method for torque. When ur valves open it releases a pressure wave and the wave comes back up through the intake manifold and the resonator uses it to silence the incoming air.

You will find that if u take your resonator out and put a strait pipe in u change where your torque band hits. Normally it shifts the power band up to a higher rpm when you take out your resonator.

It's very true that the less restriction the less the engine has to work, but you give up your low end torque for high rpm hp. This is K&N's idea for all vehicles, Hp and torque you can only use at high rpm. So an in closed box is better than a filter out in the open or an oem box cut wide open.

I've tested the open filter against the boxed filter. The Boxed filter always did better.

As for exhaust, larger is not always better, muffler flow is everything, pipe size is not as important as muffler flow. For a tuned exhaust like the stock headers, a chambered muffler is best. As strait through or glass pack type is not going to get u much but noise.

A little rule to go by for sizing exhaust flow speaking in terms of aspirated engines.
Take your engine HP x 2.2 EX 236 x 2.2 = 519.2 So a muffler rated around 520 ish should be good.

So if you look at TRD intakes you will see they use a box to draw from and they use the velocity stack built into their intake tube. Starting out with large dia pipe and funneling down to a smaller size is a great way to increase velocity. As for the cat-back, looks like a three chambered muffler that has louvered pipe, just an educated guess.

Well that's my two cents for what its worth to u...

rellim

m_pallas123

"The same reasoning lies behind the deckplate mod you don't increase the vacuum or volume but the engine does not have to work as hard to move the air meaning it can put more power to the ground..." -aviator

this is the correct answer. I deck plated my '97 and there is a noticeable difference above 3000 rpms. The difference isn't how much power my engine now has, but how much easier it has to work to create the same power. I can hear it and feel it working more efficiently.

Knightfir3

just finished reading the entire thread.. very interesting indeed. Here's my two-cents worth:

if you are so desperate for horsepower that you need to do a 1-3ish hp mod, it's time to re-gear. No argument on the sound though!

LINY4Runner

no vacuum huh? stick your hand over the deckplate hole and rev the engine...