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Discussion Starter · #1 · (Edited)
A performance shop I know got some testing on 2 Cobalt SS/SC (including mine today).

The dyno numbers are low, since it's a Mustang dyno. But the most important is that they are constants. All test in 4th gear.

1: Stock average is 192 WHP.
2: Stock + Magnaflow 2,5" rear muffler average is 200 to 202 WHP.
3: Stock + Magnaflow 2,5" + K&N filter average is 192 WHP. ***

The Magnaflow show an average of 8 to 10 WHP GAIN.

I repeat: Test have been made on BOTH cars and show exactly the same results !

*** ADDED : About the K&N high flow filter itself, gains are not easy to measure with the by-pass valve selenoid bleeding some boost. ***

My advice is to never trust a butt dyno. I know the supercharger sound is better with the airbox cover removed, but dyno shows it is running richer.

Next week I'll install a 3" pulley and will dyno it too.

Have a nice day !
 

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Interisting. Stock vs. just a cone filter with the airbox removed gave me 5whp.
 

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jmc007 said:
A performance shop I know got some testing on 2 Cobalt SS/SC (including mine today).

1: Stock average is 192 WHP.
2: Stock + Magnaflow 2,5" rear muffler average is 200 to 202 WHP.
3: Stock + Magnaflow 2,5" + K&N filter average is 192 WHP.

The Magnaflow show an average of 8 to 10 WHP GAIN.
The K&N filter makes the engine running too rich (a wideband sensor has been used) and show a 8 to 10 WHP LOST.

ok so your 2 cobalts dyno'd at EXACTLY the same hp? you cannot guage the filter + exhaust from one car and expect another car to be exactly the same

here's a link to show you the filter gives about 5 hp just from the drop in filter.


did you reset your computer after the exhaust and filter were put on? did you run the same type of gas from the same station, after driving your car for a few hundred miles so the computer remapped? you should post up some sheets.
 

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Discussion Starter · #4 ·
Hi !

First of all, yes we reset and drive some miles between the dyno runs.

Second, on the Modern Performance graph that you posted, the 221 max HP from the K&N drop in filter is a uncontrolled (unsmoothed) peak, since we can see that both lines are very next to each other. Is is very easy to copy and paste runs, even with 2 stocks runs you could see as many difference as we see on this graph. But I am not telling that MP does'nt post true tests ...

The Mustang dyno we used does'nt count those peaks (sure we saw during the runs the rising numbers as high as 196 HP for the stock runs, but the dyno software once smoothed and normalized has give a max of 192 HP.

Why did K&N does'nt offer their CAI yet ?
Why did MP (or Revitup ?) installed a Apexi AFC, and didn't post the results ?

I think all these are related to the fact that the PCM is hard to be fooled, and it make the engine running richer when the flow is higher.
 

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Discussion Starter · #5 ·
Loungelizard the fact that you gain 5whp maybe true, since the stock airbox of the redline is more restrictive.
 

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Discussion Starter · #6 ·
I also think that is for that reason that K&N doesn't suggest the E-0774 Ion Redline filter as a stock filter replacement for the SS ...
 

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Track numbers please. Make 2-3 runs with a stock filter and 2-3 runs with the K&N. Average them and compare. I'd like to see the results. I cant see why a higher flowing filter would cause a rich condition, it just doesnt make sense. Unless the flow its creating is playing tricks on the mass air sensor for some reason. It should cause the A/F to go a bit leaner if anything from the increaed airflow.
 

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MY GTP 8 U said:
Track numbers please. Make 2-3 runs with a stock filter and 2-3 runs with the K&N. Average them and compare. I'd like to see the results. I cant see why a higher flowing filter would cause a rich condition, it just doesnt make sense. Unless the flow its creating is playing tricks on the mass air sensor for some reason. It should cause the A/F to go a bit leaner if anything from the increaed airflow.
why would you want to lean out something that is getting more air. read what you just wrote. if you are getting more air in you dont reduce fuel you increase it
 

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Discussion Starter · #9 ·
Car #1

Run #1 stock : 193 WHP
Run #2 with exhaust : 203 WHP
Run #3 with exhaust and K&N drop in : 193 WHP

Car #2

Run #1 stock : 190 WHP
Run #2 stock : 191 WHP
Run #3 with exhaust and K&N drop in less lower cover of the airbox: 191 WHP
Run #4 with exhaust and K&N drop in less lower cover of the airbox: 192 WHP

Air fuel ratio for Car #2 (runs #3 and 4) was 10.5 to 10.8 at higher RPM's, so that is pretty rich.

So the conclusion is that the MAF is reading more CFM from the K&N higher flow filter, then the PCM program make the car runs richer !
 

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MY GTP 8 U said:
Track numbers please. Make 2-3 runs with a stock filter and 2-3 runs with the K&N. Average them and compare. I'd like to see the results. I cant see why a higher flowing filter would cause a rich condition, it just doesnt make sense. Unless the flow its creating is playing tricks on the mass air sensor for some reason. It should cause the A/F to go a bit leaner if anything from the increaed airflow.

who cares about the track numbers. no one gives a shit about how much faster a filter will make them on the 1/4 mile. most of us have more access to a dyno on a daily basis than we do a 1/4 track. no one is going to measure how much a filter helps out, they measure it by dyno because it is more of a controlled environment. you need to get over your track times, it's not the only way to measure the improvements made by aftermarket parts
 

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Discussion Starter · #11 ·
Selfinfiction you're damn right, and I think dyno runs are much more precise (on a same day and the same dyno) that 1/4 mile runs, since it is easy to make some driving errors with 1/4 mile runs.
 

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Rocky, if the motor is running rich, and its bringing power down by doing so, guess what youre going to want to do....LEAN IT OUT!!!

jmc, if its reading more air, which it probably is, it shouldnt add more fuel than what was already being given if the AFR was already stable. It doesnt make sense that the PCM is adding more fuel than needed and causing the engine to run richer than it was with the stock air filter. Something doesnt add up withy your logic. I know what youre trying to say, it just doesnt make sense. Why would the PCM over compensate because the MAS is reading a little more air than before?

self, are you trying to say that all that matters is that the air filter makes more power on the dyno? Yeah I guess youre right, who cares if it makes your car faster at the track. As long as you have more whp to brag about, thats all that matters!! Thumbs up to your way of thinking!!!
 

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what you said was it should lean it out due to the increased airflow.

due to increased airflow it should richen it.

yes if it sees its running rich it would lean it out.
 

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What I meant was the air filter should make the AFR leaner, if the PCM didnt overcompensate for the increased airflow. Sorry if I was a bit vague.
 

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MY GTP 8 U said:
What I meant was the air filter should make the AFR leaner, if the PCM didnt overcompensate for the increased airflow. Sorry if I was a bit vague.
gotcha now
 

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Discussion Starter · #16 ·
About the dyno loss, it wasn't cause by the MAF ... I am pretty damn sure it was caused by the by-pass valve selenoid.
 
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