Cobb DP + SPT CB = Bad MPG?

1805 Views 10 Replies 5 Participants Last post by dewey, Sep 4, 2013

jas0ndotc0m

Discussion Starter · Sep 2, 2013

I got to install an used SPT catback on my '11 sedan, and it sounds amazing! Saddly, I noticed a huge drop in MPG afterwards. Went from 19~20 to 15~16. For a noise maker, that's crazy...

Could a leak cause this huge of a drop? I looked up several forums already and the only solution I found people talking about was the o2 sensor. I never touched the thing, or even got near it. Any solution to this?

Cobb Catted DP
SPT Catback
Cobb AP 003

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twister8008

· #2 · Sep 2, 2013

This is interesting, because I will have this same setup soon. Did you try to reflash your map? I have never heard this before. We're you stock with a DP before?

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jas0ndotc0m

Discussion Starter · #3 · Sep 3, 2013

Nope, will try that next. Yeah, AP was my first mod, then sway(irrevelent), then DP, then spt cb

My 15,000 maintenance is up soon, will have subaru check it out.

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Chenstah

· #4 · Sep 3, 2013

It could be the way you drive...
Stock i was getting 18-19mpg but with invidia dp with greddy tic catback, i get 16-17 but i think its because i wot more just to hear it rumble

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jas0ndotc0m

Discussion Starter · #5 · Sep 3, 2013

Chenstah said:
It could be the way you drive...
Stock i was getting 18-19mpg but with invidia dp with greddy tic catback, i get 16-17 but i think its because i wot more just to hear it rumble

funny you say that, because the first two tank of gas was true rofl but then the last two.......proved it wasnt in my head

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dewey

· #6 · Sep 3, 2013

The turbo spools much fast now and now you're getting boost earlier. That's why you're seeing less MPGs, Get a protune it'll bring it back up, at least in my GD it did.

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jas0ndotc0m

Discussion Starter · #7 · Sep 3, 2013

dewey said:
The turbo spools much fast now and now you're getting boost earlier. That's why you're seeing less MPGs, Get a protune it'll bring it back up, at least in my GD it did.

that...actually makes a lot of sense...logically. I was going to save up and get some things ready before a protune, mainly sleeper mods that will keep my car looking stock so no one see anything under the hood like a boost controller

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Robm129

· #8 · Sep 3, 2013

I ran that same setup on my 2011 sedan. Cobb chatted DP to SPT cb. Protune on Stage 2 on 92 octane. Averaged 20 mpg.

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jas0ndotc0m

Discussion Starter · #9 · Sep 3, 2013

Robm129 said:
I ran that same setup on my 2011 sedan. Cobb chatted DP to SPT cb. Protune on Stage 2 on 92 octane. Averaged 20 mpg.

what was your MPG like before the protune?

On a side note, I shift before 2500RPM this morning and got up to 17mpg, when I normally shift around 3k.

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jas0ndotc0m

Discussion Starter · #10 · Sep 4, 2013

dewey said:
The turbo spools much fast now and now you're getting boost earlier. That's why you're seeing less MPGs, Get a protune it'll bring it back up, at least in my GD it did.

Actually now that I had more time to think about it, I realized when I first installed it that "hm, for a mod that should yield no power, it sure feels a lot faster"

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dewey

· #11 · Sep 4, 2013

jas0ndotc0m said:
Actually now that I had more time to think about it, I realized when I first installed it that "hm, for a mod that should yield no power, it sure feels a lot faster"

Actually its a mod that yields the most power and you spool faster a win in all categories. Assuming you flashed stage 2 on the AP.

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