feel underpowered at low end - cat back

[accel]

I googled a lot and know it's controversial topic.

But I do feel less power at low end. I only have XForce Varex catback system, no other mods.

And it's not only subjective. I still have stock pirelli tires. I remember how easy it was to unintentially spin them.

Now rear tires are worn a bit, and I can spin them but only when I intend to do so.

So i have a catback as the only mod I have. And I can only blame it for this situation. I did not notice the difference right away after catback install though.... so, who knows... can pirellis have better grip once you shave them a little?

Seems doubtful, but possible. I remember how slippery they were, and how I felt they got more grip after I scrubbed them a little at autox event. This feeling is more subjective than being unable to spin them though. Tires still have some thread left.

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[Grimace427]

I'm not aware of any controversy. Catbacks don't affect low end torque to any measurable degree.

 

[Genxer]

Maybe with a louder exhaust, you are being easier on the throttle than you think?

 

[NoVaGT]

Well, here's your options;

1. That cat-back exhaust I've never heard of is actually reducing low end-power.
2. It's your imagination.
3. Something else is wrong with your car.

Now, as far as the tires, consider what time of year it was when you first got your car. Were the temps lower? If so, the lower temps would largely explain the increased traction you're feeling now. And certainly the tires get grippier when worn in a bit. But I'd think that it was cold when you got the car, and those tires don't work when it's below 60 degrees.

 

[texasboy21]

Do you have any data you can provide, or are you simply going by the butt dyno?

 

[gameovergt]

to go faster you really don't want to spin the tires. We get used to the power of our cars. Also the 5.0 is not a torque monster down low. If you want that feeling I suggest an f150 intake manifold. I had one on my car but switched to the '18. The f150 has more low end grunt and is great for a DD.

 

[accel]

I'm not aware of any controversy. Catbacks don't affect low end torque to any measurable degree.[

Ive heard that in case piping diameter is bigger, you might be loosing low end torque due to lower backpressure.

And supposedly you'd gain more on the high end.

I'm not sure if I'm gaining anything on the high ebd though.

 

[accel]

Do you have any data you can provide, or are you simply going by the butt dyno?

Just clear memory that the cars used to spin rear wheels when not needed on takeoffs.

And now when tires are worn out a little, I have to really try to do that.

 

[accel]

Well, here's your options;

1. That cat-back exhaust I've never heard of is actually reducing low end-power.
2. It's your imagination.
3. Something else is wrong with your car.

Now, as far as the tires, consider what time of year it was when you first got your car. Were the temps lower? If so, the lower temps would largely explain the increased traction you're feeling now. And certainly the tires get grippier when worn in a bit. But I'd think that it was cold when you got the car, and those tires don't work when it's below 60 degrees.

Tire were initially really scary when temperatures were low. But I'm in CA, so it's not very low on average.

I got yhe car on Summer, and now it is still Summer, just next year.

Well I'd really like to believe tires are to blame

A I said - I scrubbed them once at autoX and it _felt_ like some pladtic coating was gone or something else. I felt more grip afterwards, but that's just a feeling with no numbers.

Unfortunately I haven't made a correlation between wheelspin on takeoffs back then.

 

[texasboy21]

Ive heard that in case piping diameter is bigger, you might be loosing low end torque due to lower backpressure.

And supposedly you'd gain more on the high end.

I'm not sure if I'm gaining anything on the high ebd though.

Over sized exhausts (which yours is not) dont reduce power via a change in back pressure, they have a detrimental effect on the exhaust gas scavenging. In short, there is a reduction in the exhaust 'pulling' the gases out of the cylinders. Since your headers are cats were unchanged, I highly doubt there is anything to be concerned about.

 

[SVT-DADDY]

The car sounds like its working a lot harder to do the same work, thats all it is.

 

[West TX GT]

Perhaps you have grown "used" to the car and the pedals modulation. Any changes in the fuel you are using?

 

[JCFoster]

The car sounds like its working a lot harder to do the same work, thats all it is.

Agreed.

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