Basic Air-Intake and Exhaust Modifications for Auto Cars

[Kelpie]

1. I read this from Option Mag on topic regarding the myth of modding air-intake and exos, page 110 for Dec 07 issue. They did 3 tests to a stock auto car:

a) only install aftermarket air-intake (sponsored by Simota, not drop-in type)

b) install both aftermarket exo and air-intake

c) only install aftermarket exo(branded exo was used but no name mentioned)

 

The on the road D-Box test results (air-intake, expel air, intake+expel):

a) marginal improvement than stock condition

b) Not better than stock condition

c) Better result than a) & b).

 

2. I tried to summarize. The principle of modifying air-intake is simple, i.e. aim to enhance air-exchange efficiency. At high rpm, high rev, you wanted the most unobstructed air passage to aid the combustion in the engine and at the sametimes expel out expanded air as fast as possible. So therotically speaking, it should enhance horsepower. At low-end, if the intake is too great, it actually obstructs the expanded air as it is more difficult to expel them, causing obstruction instead. It doesn't mean enhancing air-intake is no good, but its actual performance boost comes better at high rpm. So for a stop-start traffic, enhancing air-intake is not going to help alot or not at all.

 

3. They went on to do the test, very long articule. For air-intake alone, at high rev, the engine performance benefited most but at 3K rpm, the torque

figure was not impressive, Hence, air-intake alone is more suited to drivers who constantly high rev their cars. but no one drives like that on city roads. At 1K rpm, lose of pick-up is felt , it is only when the car rev up to 3k rpm above, then the speed is gradually felt.

 

4. The performance on exo alone was impressive, best D-Box result. Though torque figure was also affected but at low rpm and 2.5K rpm , an obvious performance gain is felt. Car is more lively, smoother acceleration and more eager to trust.

 

5. The combined option has the worse result. They attributed this to the need for the car to even rev harder to climb the acceleration curve.

 

6. Anyway, in conclusion, they mentioned that this is the true result but up to the reader to believe it or not. In fact, in their Q&A page, they also mentioned that no point having big air-intake but the exo can't cope and resulted in "constipation". The car manufacturers already factored in the optimal air-intake for the stock car but the exo is always a constraint because they need to run loops and ends to reduce nosie and emission to meet legal requirement. Hence, for auto car, the better mod is to start from the exo.

 

7. I thought sometimes back, someone also posted a video where an FD with aftermarket intake and exo was beaten flat by a stock FD?

 

8. Anyway, modding and tuning is a never ending story, one must really experiment and to test to confirm whether there is gain at the end of the day.

 

Anyway, this is my 2 cents worth. Please comment and feedback.

 

Thank you very much.

 

Regards,

[Adawang]

ECU tuning after intake & exhaust mods makes a difference.

If above done without ECU tune , only marginal or minimal improvement.

[Kelpie]

  Quote

ECU tuning after intake & exhaust mods makes a difference.

If above done without ECU tune , only marginal or minimal improvement.

 

Agreed. However, the scenairo is without ECU mod, so comparing air-intake versus Exos mod, Exo will have a better yield than air-intake mode.

 

Regards,

[Seanboi]

Great article. Btw tis oso applies to MT car.

 

Changing the intake alone will affect low end.

 

Btw hw abt changing the extractor to compliment the exos?

Edited March 27, 2008 by Seanboi

[Accordvtec]

so stock is the best?

[Kevs]

Well, my perspective is that the above 3 scenarios hardly provide a good comparison to draw any conclusion. For NA cars, it is really essential to design and consider i/h/e in totality, to optimise and match the intake and outflow across the entire cycle. i/h/e are typically bolt-on parts, leading to the pitfall where oftentimes, fatally considered as individual separate components for modding.

[Accordvtec]

how does a close pod filter perform then?

does it have characteristics of both drop-in and open pod?

http://www.knfilters.com/universal/apollo.htm

Edited April 24, 2008 by Accordvtec

[Kyomed]

i always thought for manual car, more air in = more combustion = more energy output, bigger xos from xtractor onwards = less hot air inside engine

 

auto cars if put open pod will hav a nice humming sound..but low end pickup suffers alot;torque oni comes in arnd 50-60km/hr..something about not enough back pressure, a problem manual cars will nv face..

[Accordvtec]

how about close pod type?

i tried before many brands.

yes, open pod kills the low end.

[Kyomed]

ur definition of closed pod = ?

an open pod inside an insulator box?

[Accordvtec]

[Kyomed]

looks like an air charger fitted with a CAI tube ley..

 

nv liked the idea of a CAI..put too close engine, useless.put too far away,cannot travel thru flood waters.

[Kyomed]

and if im nt wrong ders dis fan like thing inside the air charger..it works for low revs..

mid to high rev wise, the fan carn turn as fast as the air goes in..den ur engine will get chocked..correct me if im wrong..

[Accordvtec]

am running on stock configurations(box + resonator) with drop-in filter + CAI...

wonder will this 'apollo' increase the performance anot?

[Kyomed]

haha..depends on wad performance u lookin at ma..

 

urs is auto..?

 

CAI will definitely help due to the colder air being more densely packed with oxygen..u shud have an improved pickup at least?

[Accordvtec]

looking at better pickup at low end and slightly louder sound than current

yes, mine is auto.

backside itchy again....

tried many different brands of open pod, closed pod,etc.

Finally back to stock setup and now tempted again.

sigh...

[Kyomed]

abit OOT but i was on auto b4 and tried alota funny tings also..open pod la bigger xos la all the have and dun hav tings..nt much help cos of the way auto works..

 

i remb my gd fwen told me 'dun mod alr la..auto car canot play one..jus wasting money..'

 

den i decided to go manual..din regret it eva since;auto is v restricted due to the backpressure problem..too much air into and out is no good at all..

[Accordvtec]

hmmm...

think i got your hint.

dun waste $$

even the person selling this filter told me wont have much diff from my current set up