Jmc007

For any of you who had installed (or plans to install) a CAI (or even a drop-in filter) , I strongly suggest you to do the by-pass selenoid disabling (see the posts #5 and #6 on the first link below).

Here is the main reason : With a less restrictive filter, I noticed (and others too) that the maximum boost came sooner and max boost increased a few (depending of some conditions like the weather).

For example, those who usually saw a max boost of 10,5 PSI stock saw it went up to 12 PSI, but those who already boosted a max of 12 PSI stock saw it went up to 12,5 PSI, but not more (like mine).

About the stock Electrical Autometer gauge, there is a misconception about it. NO the stock gauge itself isn't max out to 12,5 PSI !!! The pressure (physical air) is read mechanically from a sensor and then the data is being transferred electronically to the stock electrical gauge, which shows EXACTLY the boost in the intake manifold. For those who always see a max boost lower than 12 PSI, it can be caused by several factors. Like the weather and / or the by-pass valve (butterfly) itself who isn't properly sitten (closed), because of the Allen screw on the by-pass valve actuator (little motor on the side of the supercharger) who isn't set properly.

Today I understood the TRUE reason why I got a dyno LOSS with a replaced drop-in filter. With the less restrictive filter, the boost came up quicker, but mainly tried to goes past 12,5 PSI, exactly the point that the PCM "says" to the by-pass valve selenoid to open (to vent the extra boost) (it happens somewhere around 5700 to 6000 RPM's). The dyno loss I saw for myself is clearly visible (see my first dyno graph on the post #20 of the second link below); there is a hollow at 5700 RPM.

I think that a dyno loss (at very high RPM's) is only possible for those who are already close to 12 PSI ...

About the Fujita dyno graph ... We can see on the stock baseline pull there is a hollow at 5700 RPM. But on the CAI pull, there isn't any hollow. Even if I couldn't be 100 % sure, I think Fujita disable the by-pass valve selenoid to produce a max increase of 14 HP. I think K&N didn't disable it for the 8HP gain on the Cobalt SS CAI, and I think K&N disable it on the 14 HP gain on the Ion Redline.

Those who already installed a CAI (or even a replacement filter) said that the butt dyno indicate it pulls harder between 2000 and 6000 RPM's. It's definitly true, but maximum gains will only be achieved by disabling the by-pass valve selenoid.

http://www.******************/forums/...2&page=2&pp=10
https://www.cobaltss.net/forums/2-0l-lsj-performance-tech-47/3-0-pulley-technology-pulley-dyno-results-5914/

Have a nice day !!!

eastcoastz

I agree 100%.

Xenozx

Very interesting read.

CobaltSS422

Awesome Post Jmc007

Hot Carls R/T

Do you have pics on were the bypass mod goes and instructions on how too install it?

Jmc007

I have changed the first web link for one with a pic. There is nothing to install but only a screw to plug a hose.

johnkb8

anymore info on this and if it is really good for gains and what not, any pros and cons...thanks

BeastlyTA

Im confused I guess. When you plug the end of the hose with a screw, what do you do then? The hose wont go back onto the supercharger, so do you have to plug the connector where the hose connected too?

BlAckOnBLaCK

No....you just leave the hose alone. The part that is now open on the supercharger you just leave alone. Some people put on a small filter on that side but I don't think most people do that.

BeastlyTA

Ok cool I will have to try doing that then sometime.

Roger@AEM

I doubt it. I saw bigger gains that 14whp on the dyno and never touched the bypass valve.

and butt dynos = pulling number out of your ass

LOL

No, but seriously, a butt dyno is very inaccurate, and I've felt things that have felt like more power, but when its on the dyno the numbers come out the opposite direction. Never trust a butt dyno, unless its drasticly different. But 10 or 20 hp is very hard to feel.