Thread: cut-out

I don't plan on closing mine unless i need to run through emissions or if I can help, close it before a cop pulls me over

Originally Posted by Quicklynx

I don't plan on closing mine unless i need to run through emissions or if I can help, close it before a cop pulls me over

Even if you close it he can still get you for running it open. He heard it open, and you have a cutout. That's enough. Cops aren't stupid... Most of them are car guys too.

i understand that, but im taking the risk

they dont seem to bother for exhaust here in MD that bad... if i do 70 in a 55 mph zone on the highway they dont pull us over

Originally Posted by Sabrewings

Then you'd run pig rich any time it was closed.

I have to disagree with your theory Fuel related to the cutout being Opened/Closed.

I have a DMH electric cutout on my SSEI with headers and a catback, wideband, DHP, and all the supporting. My Fuel Trims, Wideband, IPW, and MAF are the same while scanning at the track with the cutout opened or closed. Also there is no difference in the WB02 reading while cycling the cutout opened/ closed while driving..

While in theory your statement is true, its not true in the real world application

Originally Posted by 2003 SSEi

I have to disagree with your theory Fuel related to the cutout being Opened/Closed.

I have a DMH electric cutout on my SSEI with headers and a catback, wideband, DHP, and all the supporting. My Fuel Trims, Wideband, IPW, and MAF are the same while scanning at the track with the cutout opened or closed. Also there is no difference in the WB02 reading while cycling the cutout opened/ closed while driving..

While in theory your statement is true, its not true in the real world application

Well even if you figure your "theoretical" approach to the matter...the car will still run differently no matter how you slice it. Exhaust flow changes. That will throw off your tune even IF you have a wideband...how is that no real world? Enlighten me.

Originally Posted by 2003 SSEi

I have to disagree with your theory Fuel related to the cutout being Opened/Closed.

I have a DMH electric cutout on my SSEI with headers and a catback, wideband, DHP, and all the supporting. My Fuel Trims, Wideband, IPW, and MAF are the same while scanning at the track with the cutout opened or closed. Also there is no difference in the WB02 reading while cycling the cutout opened/ closed while driving..

While in theory your statement is true, its not true in the real world application

If all that is true then opening the cutout does nothing but make noise. Still a useless mod. If you get more flow it's evident in the tune.

what im saying is that the cutout has no effect of the air coming in, aka MAF freq. Thus effecting the fuel, and LTFT, and WB02 Yes it does affect the air coming out, but the car uses the air coming in, and combustion in the cylinder to make its power. After your exhaust valve opens the car dosent care how fast, or faster your exhaust is going out. Yes there might be a small reduction in the "low" end torque, but i can still rip the tires from a 20+ roll with the cutout open....


by saying that a cutout changes your tune, and fueling is like telling people if you put a catack or a mufflers (because they flow more) you need a special tune.

well... i can easily do some research on this in the coming weeks. Anyone want to help me set up a test for this?

Originally Posted by 2003 SSEi

what im saying is that the cutout has no effect of the air coming in, aka MAF freq. Thus effecting the fuel, and LTFT, and WB02 Yes it does affect the air coming out, but the car uses the air coming in, and combustion in the cylinder to make its power. After your exhaust valve opens the car dosent care how fast, or faster your exhaust is going out. Yes there might be a small reduction in the "low" end torque, but i can still rip the tires from a 20+ roll with the cutout open....


by saying that a cutout changes your tune, and fueling is like telling people if you put a catack or a mufflers (because they flow more) you need a special tune.

By your rational you don't need a tune for headers, which we all know isn't the case. Your theory is sound, but not practical. To maintain the same O2s you have to add fuel to the MAF table up top when you open up the exhaust. Otherwise there isn't any additional flow.

I am going to put them on my Trans AM but that thing is load as it is but even laouder with cutouts