Outer Limits 4x4 Board

Take a look on that mitsos user has done a dyno test to see the difference with a stock air manifold and a second test with a snorkel. The chart showed us that the Feroza with the snorkel had 3.3 bhp and 0.5 nw more than the first test.



I am also going to have a test since i have fitted a simota air filter (on the passenger side) and a new exhaust manifold 4-2-1 pipes to see how much power i have got.

So a snorkel does help for better airflow? Keep me posted as i am very interested about getting one.

Hello to everybody.
First I have to say that I chose to install a snorkel with a much bigger diameter than the one many people said I needed.

I used a safari snorkel for a 2.5 hilux.
I installed it after the original air filter, so the car has both the daihatsu air intake + filter plus the safari snorkel.

The first dyno run is with the stock air intake, and the second is with the stock intake + snorkel.

Yes it does help and it helps a lot!!

I still need to do some more tests (a run with a bmc carbon filter+snorkel and a snorkel with an even bigger diameter), but still the result is that it runs better with the snorkel!

I still cant post pictures to the forum I hope ferozamaniac will do it for me....

But you can also fit a snorkel made for our Ferozas

http://cgi.ebay.com/ebaymotors/Fibergla ... ccessories

I wish it was 27.3 degrees in tassie. interesting graph though

The dyno run was made with that temperature, because here (in Greece) it still is spring and temperature has not raised yet..... the run was also made 23.45 midnight!! That is why the temperature is so low.....
In summer time (about 3-4 months from now) the average temperature is 35+ degrees, and in daytime under the sun it goes over 40 sometimes....

Still the graph will not change in a higher temperature, because the snorkel always takes cooler air than the original intake witch is near the engine......

which would give you higher power due to the air being cooler and more dense?

alex.tas wrote:which would give you higher power due to the air being cooler and more dense?

The lower intake air temperature you have the most horsepower you get.

At any case the run was made with a low engine temperature because the car was not running for a long time and the engine bay was not heated.
I believe that when the engine bay is really hot (running for a long time) with the original air intake the car would have a warmer intake air, so a loss of horsepower, but with the snorkel the air intake temperature is not much warmed up so the drop of power should be a lot less...... at least in low speed anyway.....

But the most important is that it will not drop power.
You do not put a snorkel in the car to change horsepower (at least I didn't), it is just a side effect.
A good side effect in this case, because I've heard many cars drop horse power when having a snorkel.

The actual horsepower you get (or loose in many cases) is an addition of many factors.
- Air intake temperature
- Air flow
- Air supply
And many more.... these are the ones changed with a snorkel.

In this case all of them seem to be improved or many stayed the same at least so you can see the horsepower increasing.

P.S. My English is not that good and what I am about to say may not make a lot of sense, but still I will make a try:

If you have a straight pipe and in some point there is a bottle neck the speed of the air will increase after that point so a vacuum-type is made within the pipe which allows the car to get a bigger amount of air than the one that would actually get through if the pipe was straight.

That is why I used a much bigger diameter of snorkel and that is one of the reasons I left the original air intake in its original place.

If the extention of that theory is correct maybe if you connect the snorkel straight to the intake throttle (take out the original air intake pipe) you should see a loss of power.

I will make that test and the dyno run within the next days and we shall see the resaults......
I will also make a dyno test to the other feroza I have, which is not a safari but a hand made one to see if it is better or worse than this one!
(that should be an interesting run because the safari costed about 10times more than the hand made one!)

If ambient temperature is making any difference to the dyno runs then something is VERY WRONG. Any reputable dyno operator wil be using a correction system to iron out these differences in output caused by ambient shifts between dyno runs. Being Europe i'd suggest DIN70020

All that should be affecting the runs is the engine performance itself however its never that easy.

If the vehicle is being removed from the dyno between comparisons then errors creep in. Even how hard the vehicle is tied down to the rollers will significantly change the losses - especially with off road tyres.

Its also a factor that as transmission components warm up their losses decrease so that's also a catch with comparrisons. Its not at all unusual to see transmission losses of 50% on a 4WD giving you some idea of the problems involved is getting reliable readings.

To really be sure with such a small change its normal to do a number of runs that are discarded ( to stablize temps ) then a nuber of runs as a base line and the same number of runs modified - without removing the vehicle or wasting lots of time. A decent dyno software package will allow the creation of an "average" run from the multiple "before" and an averaged "after" if these averaged runs compare favorably then you've most likely produced a gain.

Also..... the smallest power increment that can be detected ( felt when driving ) by a trained "test" driver is considered to be 7%.

Working in the field i know what a challenge dyno's can be.

MightyMouse wrote:If ambient temperature is making any difference to the dyno runs then something is VERY WRONG. Any reputable dyno operator wil be using a correction system to iron out these differences in output caused by ambient shifts between dyno runs. Being Europe i'd suggest DIN70020

No. The temperature did not make any difference to the output of the run.
What I am trying to say is that if the car had worked for a long time before the run then the engine bay would have been heated up, so maybe the standard intake would "breathe" air with higher temp than the snorkel.

If the vehicle is being removed from the dyno between comparisons then errors creep in. Even how hard the vehicle is tied down to the rollers will significantly change the losses - especially with off road tyres.

What you see in the diagram is two lines. Each of the two lines is the average of two runs (with + without snorkel). Between these 4 runs we did not turn off the engine nor removed the car from the roller for the exact reason you are refering to.
We made them one after the other (without/with/without/with snorkel).

Even thought the two "without snorkel" run where made with 5-7 min apart, they did not change much, about 0.5bhp, the same with the two "with snorkel" runs also did not have a difference between them still the average of the two kept showing a horsepower increase with the snorkel.

Also..... the smallest power increment that can be detected ( felt when driving ) by a trained "test" driver is considered to be 7%.

When I had installed the snorkel the only thing I said is that "I don't think the car has changed to worse maybe a slight change in high range but still might be my idea because the car's sound changed.
No the power gain is not to be felt I agree with you.

Here I have to say that the MAHA dyno works in a slight different way than others:
The car starts to accelerate in the rollers, and a line of power is drown by the machine (blue line - wheel power). When you reach the most of rpm's you leave the car rolling so the engine "holds it back" till it slows down. Then you get the green line- drag power.
This line shows the "loss" you've got by transmittion+tyres+etc etc.
Τhe machine automatically corrects the "engine power" line by comparing the two above.
Between runs if you see the "drag power" changing more than 0.5hp you delete the run, and go again.
The lines at the diagram above are all made with drag line of 33+-0.5bhp.
Also as the car accelerates in the rollers there is a fan placed about 2-3 meters away from the car that provides an amount of air inceased as the speed of the car increases to make it more "street relieble"
I believe all the above make the MAHA dyno and the way we made the runs as accurate as possible........

It seems you tried to cover all the possible issues - well done ! In reality ignore the absolute numbers its change you are after, it doens't matter if you measue 10kW if your improving thats all that matters.

Just FYI the transmission correction strategy has its limits and is only approximate.

The problem is that transmissions use helical gears etc etc that have different frictional losses in different directions. Even tyres develop a slight 'Set" whcih can result in an asymetrical losses curve. So the losses created in one direction can be significantly different from those measured in the other !

This makes losses correction quite troublesome.

Bikes are even worse - its not unusual for the sprockets to be undercut resulting in significant differences.

Also - ramp rate makes an enermous difference to measured power. The inertial effects of all those tyres etc etc make a real difference. If you have the opportunity run the vehicle up at a slow and rapid ramp rate and see the difference. Nothings wrong the extra power is disapearing in inertial losses - but the curves will look VERY different.

The "correct" use of dyno's is a very very complex subject

So in conclusion does the snorkel give slightly more power?

id say at idle no but at hwy speeds yes but not enough to be noticed.

I'll say the conclusion in my way witch is:
You don't put a snorkel to increase horsepower, and if that is what you want try a different way to do it.
But if you want to install a snorkel for crossing water be sure that the engine will be running better with it.