[oldman]

Originally Posted by Nicul15

I haven’t noticed any part throttle loss with cat deletes or catless 2” LTHs on a m6 I’ve driven. Definitely strange

So you can do 6th gear at about 57 MPH no problem? Just leave it there set the cruse. Hmm... you sure now. I could do that bone stock, but that was a long time ago and many mods ago.

Since I've had the MSD since it was introduced, maybe it is a combo of MSD, 103 MM TB and LT with no cats.

With cats I have no issues, so I won't investigate this further. Please get back to me on the top question.

[Umbriel]

Originally Posted by RobbyBeefcake87

This is what I was thinking, but I could be wrong. Is a tune necessary with CA cat delete pipes? I like them because they bolt on without cutting or welding and have o2 sensors. I'm just looking for tuneless bolt ons at the moment.

Not familiar with them but if they delete the primary cats you will need a tune to get rid of the check engine light but the car will run fine with the light on. Secondary cats aren't monitored and you can do whatever you want with them and the car will not care.

[Markoz28]

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[Umbriel]

Originally Posted by oldman

So you can do 6th gear at about 57 MPH no problem? Just leave it there set the cruse. Hmm... you sure now. I could do that bone stock, but that was a long time ago and many mods ago.

Since I've had the MSD since it was introduced, maybe it is a combo of MSD, 103 MM TB and LT with no cats.

With cats I have no issues, so I won't investigate this further. Please get back to me on the top question.

Honestly sound like you might need a new tuner and I am not trying to be an ass or anything. I know the MSD causes some mid range loss of power but not sure how much. I would definitely mean towards MSD and tune over cats and headers size for that issue.

[6spdhyperblue]

Originally Posted by oldman

So you can do 6th gear at about 57 MPH no problem? Just leave it there set the cruse. Hmm... you sure now. I could do that bone stock, but that was a long time ago and many mods ago.

Since I've had the MSD since it was introduced, maybe it is a combo of MSD, 103 MM TB and LT with no cats.

With cats I have no issues, so I won't investigate this further. Please get back to me on the top question.

Yes I love driving in low rpms and skipping gears during commutes. I haven’t noticed a change and you can bet your ass we would rip the LTH right back out if it did

Prob will add msd to the car at some point so maybe that may add some more data to the situation

Will be testing the L86 intake first tho


I really hate to speculate like this but I have notorious paranoia of vacuum leaks. Tuning the MAF to inenvertily allocate for a vacuum leak will send transient part throttle driving to hell

[KingLT1]

Originally Posted by Umbriel

Not familiar with them but if they delete the primary cats you will need a tune to get rid of the check engine light but the car will run fine with the light on. Secondary cats aren't monitored and you can do whatever you want with them and the car will not care.

I have them and you definitely want to tune to maximize their potential just like headers. I have ran them both ways. The car was slower with CA cat deletes and no tune. With tune they picked up about .2 tenths. My best run with current mods is: 3.4 0-60, 7.6 0-100, 11.5 1/4 mile according to the performance page.

[Umbriel]

A lot of tuners will take cars that have light mods like that and do a couple of WOT pulls on the dyno to make sure AFR is correct and then push it out as quick as possible since it is just bolt ons. The guy that tunes mine does WOT on dyno and then drives it around for half a day and logs everything to make sure drive ability is correct. Maybe the guy who tuned yours didn't look into that? Just trying to help figure out because you shouldn't have that issue with your mods honestly.

[Umbriel]

Originally Posted by KingLT1

I have them and you definitely want to tune to maximize their potential just like headers. I have ran them both ways. The car was slower with CA cat deletes and no tune. With tune they picked up about .2 tenths. My best run with current mods is: 3.4 0-60, 7.6 0-100, 11.5 1/4 mile according to the performance page.

Yeah anytime you change something you want to tune it to maximize the potential but the car will run fine other than the light is all I was saying.

[JonD]

Originally Posted by oldman

Dude, I'm talking part throttle driving, how is that going to show on a dyno?????

Dude, talking about a subjective real world benefit is just that.
Subjective... but hey I don’t know too much

[RobbyBeefcake87]

Yea tuning is not an option at the moment so I'll just stick to ported stock tb and cai at the moment, and anything else that has perfomance benefits without a tune, like maybe a ported stock im. Too bad there's no direct bolt on secondary cat delete option lol

[oldman]

Originally Posted by Umbriel

Not familiar with them but if they delete the primary cats you will need a tune to get rid of the check engine light but the car will run fine with the light on. Secondary cats aren't monitored and you can do whatever you want with them and the car will not care.

I wanted (did not get around to it), put in the factory O2s behind the second set of cats. Back then, since I knew I was going to mod, I just got an Hp Tuner.

[oldman]

Originally Posted by Umbriel

Honestly sound like you might need a new tuner and I am not trying to be an ass or anything. I know the MSD causes some mid range loss of power but not sure how much. I would definitely mean towards MSD and tune over cats and headers size for that issue.

So can you use 6th gear at 57 MPH with LT and no cats?

[oldman]

Originally Posted by JonD

Dude, talking about a subjective real world benefit is just that.
Subjective... but hey I don’t know too much

Um it ain't me asking for dyno proof of a subjective part throttle low RPM issue.

[oldman]

Originally Posted by RobbyBeefcake87

Yea tuning is not an option at the moment so I'll just stick to ported stock tb and cai at the moment, and anything else that has perfomance benefits without a tune, like maybe a ported stock im. Too bad there's no direct bolt on secondary cat delete option lol

Well there are a few that delete the secondary cat that includes the rest of the x pipe all the way to the stock muffler. They are not unreasonably expensive.
That said the general consensus is that the primary cats are the biggest restriction.