Scrib

I finally got the AEM coupling in the mail today, so I could remove my bypass valve.

I took the car out so see if:

a) it was any quieter
b) if the horrible humming was gone
and
4) to see if there was any difference in power

a) and b) were yes and so was c) err.. 4)

Or am I losing my mind???

I'm not saying I gained 10whp from removing the thing, but now my tires break loose through first gear and I get a little chirp when going into second. I NEVER got this when I had the bypass valve on.

Maybe it's road conditions combined with cold temps. But I've driven many times in the exact same conditions as today and never had these increased power feelings and poor traction through 1st gear.

Is my mind playing Jedi tricks on me again???

SiGGy

Did you try the test with it both on and off? I'd try both on and off with the same roads, and within an hour of each setup.

I have a g-tech pro in my car. I'll give it a whirl tonight once traffic settles down. I'm hoping for a 14.1 with my new tires anyway . Maybe even a 14.0 if a do a lil work.

Had a 14.29 on a 50 degree day and near bald stock tires.

24deg 53% humidity right now, probably be a bit colder in a few hours.

b.t.w.

What did you use to join the pipes where the valve was?

edgalang

Maybe...but for sure, you are definitely taking in cleaner air now.

EricL

The bypass valve kills power -- you're not dreaming.

It kills power by:


1. Creating turbulent airflow in the intake.

2. Pulling in hot air from the engine compartment. The flaps open with the greatest of ease and you're pulling in plenty of hot air at WOT.

3. Changing the resonance in the intake.


Note: the loss from turbulence is only supposed to be around 2-3HP (from a few AEM folks).

Note: the hot air ingestion depends on myriad conditions and factors. For example, how long has the car been sitting? Has the car been moving along in slow traffic?

I did some measurements one day with an electric thermometer in the area where I would have put my bypass valve -- that will continue to sit in its box -- and the temps were in the 180-200+ F range. The temp goes down as the car moves at higher speeds on the freeway, etc...

YMMV

EricL

That too!

Anyone who buys the bypass valve should try breathing through it with their hand over one end and see how easy it is to "breathe" through it. IMO, the flaps open way too easily.

Scrib

I ordered another one of the couplers that joins the CAI to the throttle body. Another application for that part is to take the place of the bypass.

Don't even ask what I had to pay for it with taxes and shipping... :o

Scrib

Just came back from swapping the bypass back in and trying it on the same road. The results were NOT the same. While there was plenty of "get", the bypass-less CAI seems to scoot my car a little quicker.

Again though, my bypass is a little borked. When installed, it produces an awful humming noise from the engine bay.

EricL

It's just 3" silicone hose...

Scrib

I know... But I went EVERYWHERE and nobody had anything close. Autozone, PepBoys, Home Depot, Lowes, plumbing stores... The closest thing was a PVC pipe coupler. The problem was it was 1/2" inch thick rubber and the internal diameter was 3.5". That'd never make a good seal on the CAI.

I just gave up and ordered one from an AEM reseller.

EricL

Actually, some of this would have done (for future reference):

"Nitrile/SBR Rubber Hose
Black 3 ply reinforced rubber hose for intercooler pipe connections

It's down the page. The silicone is about $2.60 an inch for the 3" diameter stuff.

The "Nitrile/SBR Rubber Hose" is fine at $18 per foot ($4.50 each -> four 3x3” chunks)

http://www.roadraceengineering.com/hoseandclamps.htm

Scrib

Thanks EricL.

SiGGy

Ran a 14.150 /wo bypass and a 14.190 /w bypass. I need to wait for it to warm up a bit and try again. I still had some wheel spin. Best runs to date! 19 degrees out. I need to get my launch perfected with these new tires.

I definetly agree it's better without the bypass. Oh ya, and my second bypass now is broken too. The bonding agent they used to adhere the 2 molds together has started to give. At least I guess I can glue them back together.

mattg

is that w/ n2o, SiGGy?

SiGGy

no that was N/A. I don't have a shot in my car anymore

Best I could do was 14.29 (14.3) with the old tires. Guess these new Sumitomo HTR+ 235/45-17's helped a bit. But it's still cold out right now. Probably get a little better traction in the spring.

danny25

I took mine out the other day too, just for the hell of it, and replaced it with some of the tubing used for turbo applications.

EricL

This is just a FYI -- here is the Patent Page for the bypass valve (if anyone is interested):

AEM BYPASS PATENT (US #6,394,128)

Note: IMO, the design has changed a bit.

Exploded image of device from patent app (need plug-in):

Exploded view of bypass valve (from patent)