Cutouts and maf delete? Straight answers?!?
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Teching In
Joined: Jul 2014
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Cutouts and maf delete? Straight answers?!? I did a search but couldn't find the answers I was looking for. Sorry if this has been covered before and if so please provide links!
Ok, so I have an l76 6.0 which has headers, high flow cats and stock (super quiet) catback which I like so I don't draw attention to myself. I also have dual 3" cutouts just after the cats.
I have a 102/102 intake combo and the standard maf was too small so it's sitting on a shelf. It's been tuned without the maf, but with the cutouts plated up (didn't have electronic cutouts at the time) I can get a 100mm maf if necessary.
I heard recently that with the car tuned with them shut, if I open them my car will run dangerously lean, and if I get them tuned open it will run too rich with them shut.
1st, is that last sentence accurate? Is a maf necessary to get the most out of cutouts both open and shut?
2nd, can I get away with tuning them open and just deal with running rich when I go cruising with them shut? Or should I get the 100mm maf and get it tuned that way?
Thanks for the advice! (And let me know if I have my info all backwards lol)
Ok, so I have an l76 6.0 which has headers, high flow cats and stock (super quiet) catback which I like so I don't draw attention to myself. I also have dual 3" cutouts just after the cats.
I have a 102/102 intake combo and the standard maf was too small so it's sitting on a shelf. It's been tuned without the maf, but with the cutouts plated up (didn't have electronic cutouts at the time) I can get a 100mm maf if necessary.
I heard recently that with the car tuned with them shut, if I open them my car will run dangerously lean, and if I get them tuned open it will run too rich with them shut.
1st, is that last sentence accurate? Is a maf necessary to get the most out of cutouts both open and shut?
2nd, can I get away with tuning them open and just deal with running rich when I go cruising with them shut? Or should I get the 100mm maf and get it tuned that way?
Thanks for the advice! (And let me know if I have my info all backwards lol)
Thread Starter
Teching In
Joined: Jul 2014
Posts: 24
Likes: 0
I did a search but couldn't find the answers I was looking for. Sorry if this has been covered before and if so please provide links!
Ok, so I have an l76 6.0 which has headers, high flow cats and stock (super quiet) catback which I like so I don't draw attention to myself. I also have dual 3" cutouts just after the cats.
I have a 102/102 intake combo and the standard maf was too small so it's sitting on a shelf. It's been tuned without the maf, but with the cutouts plated up (didn't have electronic cutouts at the time) I can get a 100mm maf if necessary.
I heard recently that with the car tuned with them shut, if I open them my car will run dangerously lean, and if I get them tuned open it will run too rich with them shut.
1st, is that last sentence accurate? Is a maf necessary to get the most out of cutouts both open and shut?
2nd, can I get away with tuning them open and just deal with running rich when I go cruising with them shut? Or should I get the 100mm maf and get it tuned that way?
Thanks for the advice! (And let me know if I have my info all backwards lol)
Ok, so I have an l76 6.0 which has headers, high flow cats and stock (super quiet) catback which I like so I don't draw attention to myself. I also have dual 3" cutouts just after the cats.
I have a 102/102 intake combo and the standard maf was too small so it's sitting on a shelf. It's been tuned without the maf, but with the cutouts plated up (didn't have electronic cutouts at the time) I can get a 100mm maf if necessary.
I heard recently that with the car tuned with them shut, if I open them my car will run dangerously lean, and if I get them tuned open it will run too rich with them shut.
1st, is that last sentence accurate? Is a maf necessary to get the most out of cutouts both open and shut?
2nd, can I get away with tuning them open and just deal with running rich when I go cruising with them shut? Or should I get the 100mm maf and get it tuned that way?
Thanks for the advice! (And let me know if I have my info all backwards lol)
Depends on where you put the cutouts really...but opening them up shouldn't have too much effect on fueling. In your case, the cutouts being relatively far away from the engine and collectors and past the cats would fall in that category.
It might appear lean to the 02 sensors, but that's most likely from fresh air contamination if you have them placed near the sensors. But again that shouldn't be the case in your situation as they are plenty far away from the sensors so they should still get an accurate measure of the mixture.
It might appear lean to the 02 sensors, but that's most likely from fresh air contamination if you have them placed near the sensors. But again that shouldn't be the case in your situation as they are plenty far away from the sensors so they should still get an accurate measure of the mixture.
Thread Starter
Teching In
Joined: Jul 2014
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Depends on where you put the cutouts really...but opening them up shouldn't have too much effect on fueling. In your case, the cutouts being relatively far away from the engine and collectors and past the cats would fall in that category.
It might appear lean to the 02 sensors, but that's most likely from fresh air contamination if you have them placed near the sensors. But again that shouldn't be the case in your situation as they are plenty far away from the sensors so they should still get an accurate measure of the mixture.
It might appear lean to the 02 sensors, but that's most likely from fresh air contamination if you have them placed near the sensors. But again that shouldn't be the case in your situation as they are plenty far away from the sensors so they should still get an accurate measure of the mixture.
I was more or less under the impression that it wasn't so much the o2 sensors misreading but the change in backpressure from restrictive to high flowing yet without a maf the motor doesn't know to add extra fuel.
Anyway, I'm getting an e85 retune at a later date I'll just not use the cutouts until then.
I was more or less under the impression that it wasn't so much the o2 sensors misreading but the change in backpressure from restrictive to high flowing yet without a maf the motor doesn't know to add extra fuel.
Think about how an engine works. Fresh air enters the manifold, gets mixed with fuel, goes into the cylinder and then out the exhaust. So regardless of what you do to the exahust, if you don't make any changes to the intake side of things you're not going to allow more air in the cylinders thus needing more fuel. You can have the most free flowing exhaust in the world, the amount of air entering the cylinder will be dictated by the intake side of the engine (air filter, tube, intake manifold, head runners, intake valve etc.). Changing the exhaust is not going to magically allow more air into the engine if the same restrictions are present.
The reason you see gains from exhaust is not necessarily from more air, you just lessen the restrictions thus the engine doesn't have to work as hard to pump out the exhaust gasses thus it becomes more efficient.
Thread Starter
Teching In
Joined: Jul 2014
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That's some logic I can understand thanks! I appreciate it. I guess I am just a paranoid person lol. Better to ask a dumb question then make a dumb mistake right!? For what it's worth the cutouts are about 18" and 6" away from the front and rear o2 sensors respectively on either side so hopefully that is indeed far enough back to not change anything. Thanks again.
On The Tree
Joined: Jan 2014
Posts: 100
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From: Pittsburgh PA
Thanks for the response,
I was more or less under the impression that it wasn't so much the o2 sensors misreading but the change in backpressure from restrictive to high flowing yet without a maf the motor doesn't know to add extra fuel.
Anyway, I'm getting an e85 retune at a later date I'll just not use the cutouts until then.
I was more or less under the impression that it wasn't so much the o2 sensors misreading but the change in backpressure from restrictive to high flowing yet without a maf the motor doesn't know to add extra fuel.
Anyway, I'm getting an e85 retune at a later date I'll just not use the cutouts until then.
