If you have been following the saga of Nix, you might remember one of the While I'm At Its was a cool air intake.

Husband fabricated the snoozel hole in the front and scrounged the air tube somewhere. This evening I Finally got the chance to see just what difference it makes. A LOT!!

Until tonight I've had traffic to deal with so couldn't discover the full potential of this addition. But, well, ya see, there was this car, poking along, and we were past the Passing Zone, and well, there was sort of a short Merge lane for an intersection, that sort of makes a Very Short passing zone if one is set up to use it. It's all quite safe, and I don't even think it's terribly illegal.

So anyway, the air was cool, and this short lane was coming up, and this pokey car was poking along, so I got set up, and I stuck my foot through the firewall, and that 700R kicked down into Pursuit Mode, and Nix took off like she'd been shot off the flight deck if the Carrier Nimitz!

I was sort of watching the road, because it was dark as I mentioned, but Man she was pulling strong and just kept pulling, and I glanced at the tach, and the needle was a little after 3 o'clock and she was Still pulling, but I was Well past the slow poke having Soundly blown his doors off, and one of the S-curves was coming up, so I let up just a bit and it shifted into 4th, and the needle dropped back to 12 o'clock and I took the "S" lickity split!

WOW!!

Nix has Never performed like that, no matter the weather, terrain, traffic, wind conditions, Nothing!

If the speedometer worked I'd have some idea of my speed, but those positions on my tach are 4700rpm and 3000rpm, a bit past comfortable cruise.

Oh Boy was that Ever worth the trouble!
I'll have to gas up again tomorrow I suppose, but WOW!!
(';')

 

Sounds like you will be gassing up regularly! Enjoy

 

Well, I really like what you did to Nix!

But I have never seen a dyno-test in which a cold air intake or an open air filter made a difference of more than a single horsepower, or torque.

So your car may run well, it has nothing to do with the air intake... really.

An example:

 

Clarke:
Oh Yeah! Lotsa full ups!

Willfred:
Thank you for the complement, but:
First, their car DID have an increase in power output of 3%, which in the real world would be the difference between winning or not as one of the guys mentioned.

Second, their car is on a DYNO, not Real World Road conditions. It might very well be true that a new Honda's stock air intake system is superior to that possible on a 40 year old Chevy engine but wouldn't we be surprised if it wasn't?! I mean, Really!! 40 years?!

Third, the movement of the car through the air, thus forcing cooler air into the engine at whatever speed (in my case at Least 90mph) is not Even taken into account with Any of their DYNO tests.

When they put a car on a DYNO, AND do this test in a wind tunnel, they Might have something to crow about depending on the outcome. Until that time, it's Only a DYNO test, and as with All DYNO testing, it does not reflect Real World Conditions as is always stated in the fine print.
(';')

 

You won't notice an increase of just 3%.

rule of thumb is that a 10% increase is required before you can exprerience it.

Adding to that, this video was just an example. There are more with probably better conditions. I will look for them and let you know.

 

Next time, use a GoPro and post the video here for all to enjoy!

 

I agree, I probably wouldn't notice a mere 3% unless it was switched on and off in the same run. Since I DID notice, it had to be more than a measly 3%, and besides that, I don't live by 'rules of thumb.' Whose thumb? Those are only *suggested outcomes.*

I'm not going to take up server space arguing this point, I KNOW what this engine has done before and what it does now with the Only change made. When there's a *Proper* test, reflecting Real World conditions, with and without cool air intake, I'll take it under advisement.... maybe. Or I might just ignore all such poo-pooing and and nay-saying, and continue to drive the wheels off.
(';')

 

I'll look into that! Thank you.
(';')

 

Interesting, no question.
1. 3 vs 10. If the base is poor, a decided advantage will show. Conversely, if the bas is not all that bad, the improvement will be less.


2. Dyno vs real world. Air intake in a hot shop vs lots of fresh air n the road. or not so much in stop and go traffic. Hot day vs cool and raining, etc.


3. I think Elinor and NIX got lucky. assisted by Hubby's skills though. A fussy SMOG tech might have flunked it for a :"non CARB approved air intake"!!!


4. Air density and the IC engine are well known to the trade.


But, that is one of the reasons we have a forum. Exchange of views and learn.
Not to mention fun!!!


Good work.


Carl

 

Ah, the old butt dyno vs. laws of physics debate.

I'm afraid that the point goes to Wilfred on this one. Gains from a cold air intake even in the best circumstances are almost negligible and are certainly below the threshold of what can be detected honestly by even a well calibrated butt dyno.

The science behind it is not that complicated.

The primary advantage of a CAI as it's name suggests is 'cold air'. The colder the air entering the engine, the denser it is. Denser equals more power. The rules of thermodynamics shows us that for each decrease of 11*F in air intake temp, engine power will increase by 1%.

Unfortunately, this also means that the referenced 10% power increase required for a driver to notice a before/after difference would require a drop of 90*F intake temp through the addition of a CAI. I've never seen a car that heats it's own intake air by even a fraction of that.

The 3% difference seen in the video, assuming it's not just dyno scatter, might be attributable to the engine ingesting the above mentioned hot air with the stock system. A 33*F increase in engine bay temps while sitting static is not unimaginable.

Again this also unfortunately works against the real world gains of a CAI as there is considerable under hood air circulation once a car is in motion which means that a 90*F or even a 33*F difference just does not exist. This supports the idea of static dyno test results being misleading.

The concept of the forward motion of the car 'forcing' air into the intake has merit but the gains at typical road speeds again are negligible. Essentially, a vehicle speed of at least 100 MPH is required to create a noticeable gain and also requires an unobstructed path for the air, well outside the turbulent air behind a grill and outside the boundary flow of typical body panels. None of the foregoing exists in the present discussion.

It's also possible that the ducting losses introduced with a CAI offsets what little the reduced intake air temps have gained.


Background:

My other car hobby is old Corvettes. The 1973-'75 models featured a factory ram air/cold air induction system that would supposedly reduce 1/4 mile times by a full second compared to the open underhood system of previous years.

For grin and giggles, I tested the effectivity of the system on a stock '73 small block, most likely producing similar or more horsepower then the Jag in question here.

Long story short, the system was all 'show' and no 'go'. Net gain with the factory system, (using the formula of 1% more power for 11*F temp drop) was a miserable 3/4 of one horsepower being seen only at speeds of 100MPH and proportionally less at 'legal' speeds.

Thermocouples installed under the hood and inside the intake indicated local temps of 20-40*F higher than ambient while the car was stopped or crawling in traffic, but the difference dropped to almost zero once the car was in constant motion. Notably, the best results were noted while the car was being driven into the wind, blowing a constant 20MPH at the time.

It is thought that the extra weight of the factory system would more than eat up the power gained, not to mention the increased aerodynamic drag of a net 120MPH headwind.

 

My feeling is it is Elenors **** and elenors foot and elenors car. If she says it feels faster, then it IS faster. No need for science and arguments. The warm air/cold air debate is probably not even relavent. My guess is that not enough free flowing air was getting under the hood to be sucked in cleanly and fast enough under full throttle before the snorkeling was done. well done Elenor and hubby. Nix is definitely NOT sulking in the corner anymore :-)

 

Forget about cold air intakes, and if they work or not, EVERYBODY knows that a good wash and wax adds horse power!


The way NIX shines, that alone should be worth more than 10%!

 

Carl might be right, we got lucky. Up until now, this car has suffered with the same malady as all 70s cars, air intake in the engine compartment, which won't be much cooler than the 180F thermostat. This time the engine was getting 60F air from outside and it was being rammed in at considerable speed.

I don't have an engineering degree nor do I have access to sophisticated test equipment, but one of the Concrete Principles we all recognize in this section is the Feel Good Factor which never lets "science" get in the way. That run Felt Really Good (better than the Z06 felt and with a Lot more class) and I make no apologies for it nor for sharing the excitement. However, in view of the controversy I've started here I'll try to be more, "objective," in my reporting of such experiences in future.
(';')

 

I had no intention of diminishing your feel good experience. I get the same kick after a good wash and wax job- I guess I should try it sometime on the car too.

You did say "When there's a *Proper* test, reflecting Real World conditions, with and without cool air intake, I'll take it under advisement.... maybe. "

So I responded with a proper test.....


There's nothing quite as cramped and restrictive as a '70s Corvette engine compartment. An XJ is the 'wide open prairies' by comparison. At no time during the tests I performed did the temps exceed 120ish (40*F above the 80* ambient) and that was only with the car stopped dead for an extended period in traffic.

As stated above, once moving the engine compartment temps dropped to only a few degrees above ambient. This explains why the CAI would had negligible effect.

 

With everything you do, there is always a risk that you think an improvement is due to what you have done. Just the thought of improving something can make you feel like things have improved indeed.

Still, if you FEEL better in your car, it was worth it, right!

And I can agree that my car runs better when I cleaned it inside and outside. Just like my brakes worked better after I painted them red.

My only concern for the cold air intake was that you could make other people follow your example, while it is far from certain the power increasement is due to your air intake modification.

 

If there is genuinely no science behind the long regarded premise that rammed cold air creates stronger combustion than comparatively trickled hot air, then all I can say is, we've been well and truly duped for donkey's years! Should the whole thing be a myth, then there are mammoth sectors of the car industry (vehicle manufacturers and after-market component makers) that have dined out on our ignorance (at worst) or perception (at best), the spoils from which would be incalculable - all in the name of creating and perpetuating a myth.

I suspect that consensus will never be reached on this topic, so little point going round in circles methinks.

 

There is science behind it. Cold air does improve engine performance. But in a naturally aspirated engine the difference is too small.

When you have a turbo, for example, the air gets really hot. That is why an intercooler DOES make sense.

 

So assuming the science is factual, but miniscule in effect on a NA engine, surely my point stands. I suspect most buyers investing in CAI paraphernalia would be bolting it onto a NA engine believing it will make an impact worthy of the outlay.

 

I think you are right, and that is exactly the reason why I shared my doubts/concers regarding CAI. To prevent people from buying expensive Open Air filters, Relocating air intakes etc for almost no reason.

Even for a turbo engine, a CAI is not relevant. Because the air will get so hot due to the turbo (this thing can be literally red hot on a good run), that it won't make a difference if your incoming air was 10 degrees cooler.
I dont have a lot of experience with superchargers. These warm up the air less, but I can't say what the effect will be.

 

So those Ram Air Suzuki's I shelled out for in my youth just made me feel good and fed Michio Suzuki's offspring and executives.
I certainly felt like I was getting value for money.



Elinor, if it feels better it must be better. When I head to higher colder parts of NSW my car runs and feels so much better.
I always put it down to the altitude and colder air.