# Intake rant



## AZ007 (Sep 26, 2014)

This is my little rant about why you should *not* buy an intake. I was considering one myself, but I've done enough research to know it's a bad idea, and here's why.

1) You'll be messing with one of the 1.8's most carefully-engineered features: a variable length intake. At low rpm's the intake is 36" long for better low-end torque. At 4000 rpm a shorter intake path opens up. I'll take low-end torque over high-rpm torque or horsepower any day. Read more here:
Chevrolet Cruze: Fuel-Efficient Powertrain Offerings Led By Technically Advanced Ecotec 1.4L Turbo

2) K&N advertising is misleading. Take a close look at this dyno chart:
http://www.knfilters.com/dynocharts/69-4522_dyno.pdf
You notice it cuts off at ~2200 rpm? I would bet that's because a K&N yields less low-end torque.

With that being said, there might be a few people who would benefit. If you're driving almost purely on the highway or full-throttle, I could understand why you might want more airflow.


----------



## spacedout (Dec 7, 2010)

Your first bullet point is incorrect, the 1.8L has a variable intake Manifold, not the air intake(air filter and piping). Changing the stock air intake with any aftermarket one would not effect how the 1.8L intake manifold works in any way.


----------



## LS6rally (Dec 2, 2014)

Your Second Bullet point is silly as well. K&N doesnt "deceive" anything. First off, its a 3rd gear pull, how low do you want the RPMs? K&N never claimed that you would gain in the low end, they are showing peak gains, just like any other aftermarket performance part manufacturer. When you buy a cam that claims 60HP, you dont get 60 horse more across the board, there is an RPM range where you will see your best gains.


----------



## dirt dauber (Dec 24, 2014)

he's talking about a 1.8 litre then his info is about a 1.4 litre turbo?


----------



## AZ007 (Sep 26, 2014)

dirt dauber said:


> he's talking about a 1.8 litre then his info is about a 1.4 litre turbo?


What do you mean? Everything was about the 1.8.


----------



## AZ007 (Sep 26, 2014)

LS6rally said:


> First off, its a 3rd gear pull, how low do you want the RPMs?


It doesn't matter what gear it's in, the engine rpm/torque and rpm/hp curves will look the same. Just scaled up or down. So I guess you'd rather be oblivious to how much low-end torque you lost?


----------



## SneakerFix (Jul 28, 2013)

AZ007 said:


> It doesn't matter what gear it's in, the engine rpm/torque and rpm/hp curves will look the same. Just scaled up or down. So I guess you'd rather be oblivious to how much low-end torque you lost?



When your on the dyno it does matter what gear your in.. 
Have you tested this out for yourself? 

Short ram intakes gain more low and mid range HP 3-5 and 4-6TQ. Now adding a cold air intake will make you lose the low and mid range power and torque because your gains will now be in the mid and upper range of the power band this is where tuning comes into play with HPT or efilive


----------



## nick993 (Dec 30, 2013)

I thought it was the other way around? sri loses low end and cai makes less top end.


Sent from AutoGuide.com Free App


----------



## Slammed2014Eco (Feb 13, 2014)

nick993 said:


> I thought it was the other way around? sri loses low end and cai makes less top end.
> 
> 
> Sent from AutoGuide.com Free App


Pretty sure sneaker is correct air has less time to travel on a sri so it makes the power quicker but has more heat soak, as to the cai which has more time to travel resulting in colder air and more power up top. Correct me if I'm wrong not my area of expertise lol


----------



## SneakerFix (Jul 28, 2013)

Slammed2014Eco said:


> Pretty sure sneaker is correct air has less time to travel on a sri so it makes the power quicker but has more heat soak, as to the cai which has more time to travel resulting in colder air and more power up top. Correct me if I'm wrong not my area of expertise lol



I think I'm right and wrong lol. Pipe diameter, filter used, engine set up N/A, F/I, air box all play a role in your power band when using a CAI or SRI


----------



## Blue Angel (Feb 18, 2011)

SneakerFix said:


> I think I'm right and wrong lol. Pipe diameter, filter used, engine set up N/A, F/I, air box all play a role in your power band when using a CAI or SRI


Yeah, you can't really generalize too much when it comes to intake piping. Every engine is going to react differently, every intake will be designed differently and with its own compromises.

GENERALLY speaking, a short intake with the filter under the hood will draw warmer air than a longer cold air intake will if its filter is in a good spot. Colder air makes more power.

The length of the intake track CAN have an effect on low end torque, but it would have to be a significant difference in length before you would notice a change, and you would have to do dyno testing to quantify it. Seat of the pants impressions on small changes are rarely correct.

I doubt K&N are hiding anything intentionally with their dyno chart. If anything, people are generally guilty of fudging high RPM results, not low ones. It is common practice to start a dyno pull somewhere between 2-3000 RPM. I personally wish every dyno pull started at idle, mostly because I'm a geek, but that's not the way it's done very often.


----------



## XtremeRevolution (Jan 19, 2012)

Blue Angel said:


> Yeah, you can't really generalize too much when it comes to intake piping. Every engine is going to react differently, every intake will be designed differently and with its own compromises.
> 
> GENERALLY speaking, a short intake with the filter under the hood will draw warmer air than a longer cold air intake will if its filter is in a good spot. Colder air makes more power.
> 
> ...


K&N is known to do the following with their testing:

1. Dyno pull with the hood open on an SRI so it doesn't pull hot air.
2. Compare worst or pulls from stock to best of pulls with intake to present power gains.
3. Dyno immediately after an ECU reset with their intake. 

A while back I went out and looked up a good number of dyno charts with their intake and discovered actual power gains were less than 1/4 of advertised. There was a K&N Typhoon intake for a Lexus IS that advertised 28hp. The owner gained 3-4hp on the dyno. 

You're right, they aren't hiding anything. They're blatantly fudging the numbers.

http://my.is/forums/f136/dyno-tested-k-n-typhoon-intake-vs-stock-airbox-vs-diy-intake-mod-413122/


----------



## SneakerFix (Jul 28, 2013)

Guess they updated since the new findings 

Lexus IS250 Cold Air Intake - Performance Air Intakes


----------



## Dragonsys (May 27, 2013)

AZ007 said:


> What do you mean? Everything was about the 1.8.





AZ007 said:


> Chevrolet Cruze: Fuel-Efficient Powertrain Offerings Led By Technically Advanced Ecotec 1.4L Turbo


This link is about the 1.4L Turbo, not the 1.8L N/A


----------



## Blue Angel (Feb 18, 2011)

XtremeRevolution said:


> K&N is known to do the following with their testing:


Sorry, I wasn't clear. I meant hiding anything WRT low RPM torque losses.

Absolutely, almost EVERY SINGLE PART MFR will give you the best case, stars aligned, wind blowing just the right way, glass half-full outcome. In no way are they going to tell you that their mod costs you $100/hp gained! How would they sell anything?


----------



## obermd (Mar 3, 2012)

Blue Angel said:


> Absolutely, almost EVERY SINGLE PART MFR will give you the best case, stars aligned, wind blowing just the right way, glass half-full outcome. In no way are they going to tell you that their mod costs you $100/hp gained! How would they sell anything?


And they will always compare against the worst of the competition.


----------



## Blue Angel (Feb 18, 2011)

obermd said:


> And they will always compare against the worst of the competition.


The best is when they take a baseline dyno of a completely stock car, then compare that to a dyno of the car with their product AND a tune to optimize everything! They fail to tell you that 2/3 of the improvement came from the tune! This is the case with the headers I bought for my ZO6... they used to claim 40hp increase and compare to an otherwise stock car!

https://www.lgmotorsports.com/corve...g-motorsports-c5-1-3-4-super-pro-headers.html

Little did I know at the time, 25 of those 40hp came from the tune itself...


----------



## AZ007 (Sep 26, 2014)

The chance that the dyno pull "happened" to start right where the K&N curve crosses the stock curve is slim.



Dragonsys said:


> This link is about the 1.4L Turbo, not the 1.8L N/A


Read the link. It goes into some detail about the 1.8 towards the end.


----------



## daasian (Feb 5, 2014)

The point of the cai is to take cool air outside the engine Compartment. The cooler the air the more power you make. "Theoretically"


----------

