Cold air induction/airbox

[SKiddell]

OK Sean

I'd be very interested to hear what the engine-maker says on the subject of cold/hot air intake via airbox/under-bonnet filters.

Why do you need to hear what "the engine-maker" says, why is this engine any different from any other combustion engine?

Why do you always find it so difficult to accept what
1. World renowned engine tuners say
2. Physics says
3. Any one who knows anythng about engines says

I say show me sound data that says that cold air induction does nothing or is detrimental.

Every performance internal combustion engine you can name strives to minimise under bonnet and induction temps, to reduce detonation, improve consistency of fuel air ratios and get maximum power, whats not to like about that


To challenge the logic of cold air induction challenges one of the basic principles of internal combustion engine tuning.....or maybe you've discovered some new law of physics that circumvents basic principles.

It is irrefutable that on a like for like engine, the one with a well designed cold air induction system (versus one drawing hot air from a semi-enclosed engine bay) will perform better.

Plus (my other point) if you run open trumpets, socks, K&Ns etc its more difficult to tune the carburation for "general" use, its jetted to suit the environment in the engine bay and not what is going on in the real world.
Taking air from outside of the semi-enclosed engine bay allows you a better chance to tune the car for the "middle ground"

Discuss (using sound scientific principles not some myth and hyperbole)

 

[SeanDezart]

Steve.

This can become a very educative thread covering future, present and past solutions.

But please tone down your words because as is, I don't feel that any discussion with you will avoid being over emotive.

I didn't return to this site to argue - phrases like'

Why do you always find it so difficult to accept what

Discuss (using sound scientific principles not some myth and hyperbole)

are not going to induce anyone, least of all me to discuss with you.

It is irrefutable that on a like for like engine, the one with a well designed cold air induction system (versus one drawing hot air from a semienclosed engine bay) will perform better.

Agreed.

Why do you need to hear what "the engine-maker" says,

Because you (who have developped the airbox) said "

Ive spoken to Eiji on a number of occasions (emails) and found him very knowledgable,

and

If I didnt build my own engines, I would chose Datsun Spirit EVERY time

So sorry, I've calmed down and I'm staying down. I'll come back here if I'm not to be 'attacked or provoked' and perhaps at best serve as a catalyst (with my limited input and largely less scientific than yours) to open the discussion wider........because I believe that it merits a wider look and I hope that you'll respect that and be curious enough to want to peek.

Later dude.

 

[AliK]

Emotions aside, logic dictates that cold air should be better than warm - but I'm also very interested to see by how much and in real world driving. Is the air temp at carbs that much higher at say 40/50MPH than in front of the car?

I doubt dyno plots would show that, so is there data to show the difference in real world driving and is it significant enough to notice if you're not chasing 100th of seconds?

 

[SKiddell]

Sean
Do not confuse my passion with "emotion" right now im as cold as ice but please dont try and provoke me, im asking you to evidence your reluctance to accept the technology, but all you do is put quotes around my statements as if it somehow vindicates your somewhat stoneage approach......or maybe you havent changed and just love baiting folks, so far you havent produced one shred of evidence to support your sid of the story, whilst I have dyno sheets and real world performance data.

Want more
Johhny Mason, cold air box......Hall of Fame class 1, 13.05 second quarter mile
Terry Taylor, cold air box..........Hall of Fame class 1, 13.1 second quarter mile
Steve Kiddell, cold air box........Hall of Fame class 1, 12.453 second quarter mile

The next closest (to Terry) is a full 0.5 of a second away which doesnt sound a lot but in "real world terms" it equates to 5 car lengths, from me they are 15 car lengths away........they didnt use a cold air box.

There has not been an NA car that could get anywhere near the low 13's without an airbox.......FACT


Your turn, Please evidence REAL proof

And please dont partonise me with "tone down your words"

Lets stick to the facts shall we.

Fact
The automotive world as a whole supports cold air induction
You are challenging cold air induction
I have provided scientific fact as to why it works
You still challenge it
I have asked you to provide scientific fact as to why you don't support it
You can't

 

[SKiddell]

I doubt dyno plots would show that, so is there data to show the difference in real world driving and is it significant enough to notice if you're not chasing 100th of seconds?

Firstly I appreciate your comment but please dont think I purely chase 100ths of a second, I have driven my car on many of the circuits in the UK, not just on Japfest parade laps but serious track days, plus it has done as many road miles as any car on here.

Back on track (excuse the pun) Dynos can simulate things to an extent, the automotive industry uses dyno cells for development.
We tested Airbox versus no airbox, the results were so dramatic that even Dave Walker was suprised, Dave who?, oh just the guy who wrote the Haynes manual on Fuel injection thats all.

Is the air temp at carbs that much higher at say 40/50MPH than in front of the car?

Yes, it is, I ran temperature strips on the inner wing right opposite the inlet tract and they indicated 50 degree plus temps on a moderate warm day, we specifically didnt drive the car hard on a 10 mile round trip to the nearest petrol station that sold 97 octane

Back on the dyno We saw a 20hp drop off without the box at 3000 - 4500 rpm personaly I dont want to lose 20HP but even worse we detected "detonation" and had to put it back on.
Now some of this is due to the cooler, denser air but some of this is due to cooler air plus the management of reflected pulses, which if managed badly will interfer with the inbound fuel/air pulse, if managed correctly can enhance them (see intake resonance pulse tuning)

The tests we have performed demonstrated excellent results, but if you want real world........there is no one better than doing this than the automotive giants like err Nissan, how many Nissans since the late 70's use air drawn from the inside of the engine bay?.......ask yourself why all car manufacturers have moved away from feeding the engine hot air.

We also collected data for a wrapped header versus a none wrapped header, we did several tests with varying inlet tract lengths, several test on different octane fuels right up to 106, over the past 7 years I have spent nearly a couple of grand on dyno testing one thing and another, learning how things work, spending countless hours with an absolute expert.

 

[status]

Skids has a valid point,when we were at bruntinphorpe my car was running a bit rough but skids worked out the quarter mile to about 13.3 correct me if im wrong,i have the said box but nothing to compare,i might be talking total **** but ha ho

 

[AliK]

Skids, agree with what you're saying - I had no idea it made that much of a difference at speed.

On the wrap front, I was seriously considering that for my headers next time I have them off (and the fuel lines). But I read somewhere that they reduce the life of the headers, is that true?

Have to say, never understood the rationale behind non-cross flow engines; especially in Zs given the wasted empty space on the opposite side of the engine.

 

[atomman]

I worked on a project a few years ago and we had our own in house dyno, We built a 22 degree V10 engine that fitted into the car we designed, a supercharged version, NA version with variable length trumpets and a hybrid version,

I spent many, many hours sat on that dyno writing maps, analysing the flow of the different inlet housings we had designed thermo couple data etc...

The only data I ever got that proved that is was better to take warm air from the engine bay rather than outside was when retro fitted out hybrid system on a few Diesel transits vans and sprinters and they gave better MPG with the warm air ,

I have just put triples webers on my car with trumpets and socks but this is just a stop gap until I get round to building a cold air intake for it.

 

[SeanDezart]

Steve.

I apologisie if I gave the impression of provoking and patronising you - not at all my intention which was merely that the tone of the discussion be calmed to launch an open-minded discussion upon variants and methods on coolong the induction.

I have already agreed with you - I do not seek to 'debate' your findings merely add to and broaden them. Whether what I feel I can bring are agreed with or not is not important - it is the discussion of them between all that counts - the raison d'être of a forum.

Right now, I don't feel the atmosphere on this thread is ready.

 

[johnymd]

Oh dear.....

Good to see you back Sean, just a shame it's gone this way. I'll look for another thread to read.

 

[SeanDezart]

I agree John.

I was looking forward to an open-minded discussion between all interested here on the forum based upon Steves' hard-earned research as accepted fact and hopefully enlarging the findings WITHOUT casting doubt upon them !

Steve hasn't grasped that notion, perhaps as a throwback to past clashes so I accept part-responsability....but in my defence, I have agreed with him here and explained why I thought it pertinent to have the engine builders' opinion - even if it is to dismiss it such as occured re harmonic dampers.

Steve is very intense about his findings, he has a right to be proud and yes his observation is correct, Nissan incorporated cool-air induction - look at 280ZXs and I have an S110 Silvia which takes air from in front of and above the rad support panel.

But if a friendly discussion cannot be fomed upon the basis of his data, it'd be bette to fom a tutorial subject and close the thread to allow the reading of only.

I'll come back when the first post has been reworded by Steve and the remainder of this thread cleaned up with most posts deleted.

 

[morbias]

Just curious...

Say you have triple carbs fitted, would it not be beneficial to have an airbox for each carb rather than one airbox for all three carbs?

Would that not allow finer tuning of the resonant pulse and help negate the effect of each intake tract occupying a different position inside the airbox, but also reduce the effect of other cylinders breathing at the same time as would happen in a single airbox?

 

[datsun dave]

Just curious...

Say you have triple carbs fitted, would it not be beneficial to have an airbox for each carb rather than one airbox for all three carbs?

Would that not allow finer tuning of the resonant pulse and help negate the effect of each intake tract occupying a different position inside the airbox, but also reduce the effect of other cylinders breathing at the same time as would happen in a single airbox?

It's a lot of work to have all single air boxes and try and fit them all (x3 airfilters) I have had a air box from Steve on my previous L28 engine and did notice a improvement with it fitted.

 

[morbias]

Theoretically speaking of course! Maybe an airbox for each cylinder would be an optimal setup but logistically close to impossible, I was only wondering about 3 airboxes on the basis of diminishing returns with 6 airboxes regarding cylinders breathing at the same time (the cylinder opening sequence shouldn't really be a problem when 1 & 2, 3 & 4 and 5 & 6 have an airbox each), and there still being a possibility of putting a triple airbox setup into practice

 

[Albrecht]

There has not been an NA car that could get anywhere near the low 13's without an airbox.......FACT

Apart from fifteen years ago....

 

[morbias]

That fuelling setup looks kind of crazy!

 

[ben240z]

Apart from fifteen years ago....

Now play nicely all of you as this is interesting technically

 

[Albrecht]

He's tidied it up a bit now (and gone faster...):

 

[SKiddell]

Sorry Alan (and Ben from a PM) I should have made it clear (my bad at 2 in the morning) that I was refering to the UK Hall Of Fame for which my data is correct. In a global respect you are correct.

I am not disputing that a car will produce adequate power/performance to a certain/acceptable level with open trumpets, my point is given that accepted automotive science supports that cooler cleaner air will produce better results over hot less dense air plus help improve the lifetime of the engine why would anyone choose that latter ? yet people do.

Sean you do a unique way of intimating that you disagree (maybe its a language thing who knows) with comments like

I'd be very interested to hear what the engine-maker says on the subject of cold/hot air intake via airbox/under-bonnet filters.

which I take as a direct challenge then when someone supplies data to the contrary you quickly do an about face with

I do not seek to 'debate' your findings merely add to and broaden them

which isnt quiet right is it

Im not trying to force anything on anyone here, I am just trying to make a point that open trumpets/socks are not the best option for engine longevity or optimal performance
And K&N filters all little better than the latter as they still draw heated air into the engine all be it filtered.

 

[Albrecht]

Now play nicely all of you as this is interesting technically

There's no question that Steve is right, but some of us just don't want to run with filters or airboxes...