Thread: GXP Exhaust

I'll probably do some more tuning in a week. I'm real busy with the business.

Originally Posted by Beamie

Just thinking and knowing the principle theory about it, you definitely will through a code. I'm trying to learn more about the HP Tuners program and when I get better at it I'll probably be doing a lot more mods. I'm ol' skool. Give me time to catch up. we ol' men are like fine wine. We might not be as quick as we used to be, but we're still fast enough to kick your A _ _! Well, you know what I mean.

Beamie,
I've got the code issue. I'm running a magnaflow exhaust which sounds beautiful. My exhaust is not throwing the code. However, my GXP has an electronic cut out which allows it to bypass the mufflers and go straight exhaust from the cat. every time I open this it throws the check engine light.... Do you have any suggestions on how to correct this code or are you aware of a tuner system that will correct this? My computer throws the code b/c of too much air flow then the exhaust is wide open. Thanks for your help.

http://s75.photobucket.com/albums/i288/ucquality/?action=view¤t=MOV02869.flv

i got flowmaster single chamber,res delete and knn cai, man it just dont look like that car should make that kinda sound lol i love it. only set me back maybe 600 for everything

dont remove the resonator unless you want rasp...get some new mufflers if you want a deeper sound

^^GXP dude...he's got a V8

Originally Posted by GXPFiend

is the magnaflow kit worth it? or should i just get some mufflers and remove the resonator. BTW I have an 08 GXP

A lot of people like the magnaflow sound with the matched resonator, and instead of 2.5" to the Y and then 2" to the muffler you get 2.5" the whole way. Plus it bolts on easy and looks really clean, and you get measurable HP gains. As far as bolt on mods go, I've never heard anyone complain after they bought one.

That said, I saw an article by a Dynomax engineer that claimed there is only 2-4 HP to be found in the piping if you keep the same size or make a small increase. Now if you were making a lot more HP than stock, or had a power adder, then the exhaust pipe size will become a restriction and rob more power, but for a mostly stock car there isn't much power there.

You DO take a big hit in the cat and the mufflers. You can buy most aftermarket mufflers for about $70 each in a 2.25" size, and a Hogan downpipe with a high-flow cat is $300. Throw in a trip to your exhaust shop to get the mufflers welded on, res delete, and maybe some tips, and I think you get more bang for your buck. But since there are so few bolt-ons for this engine and every HP counts, I think the Magnaflow kit will max out your performance even if it costs more.

Personally, I'm eyeballing a set of Hooker Maxflows (quiet at idle and cruise, really loud at WOT, nice power gains) if they fit (I haven't measured yet), but Magnaflows are my second choice. I like glasspacks over chambered mufflers, but a lot of guys love that flowmaster sound too.

BTW, I heard there are ways to get the kit cheaper than $698 just by shopping around and asking. The cheapest I've read is $516 shipped, but I don't have any personal experience.

$280 for mufflers and install?

Your getting bent over

I'd get a catless 3" DP and have someone that does good work custom make a catback..its cheaper

wow, I didnt pay but $250 for 2 flowmasters, res delete and new tips all installed. may not the cheapest but it was where im at.

they are beast if you get the single chambers, I had the dual chamber first but they didnt quite put out the noise I wanted...I mean they sounded good just not loud enough. just look at my videos on youtube to see what singles sound like for the newer vids, the older ones like the accel. and the dyno are the dual chamber.---------oops just went and checked, youve already commented on a couple of vids

If you don't mind me asking. What is the intended purpose of you modifying your vehicle. Race, Street, or Bragging rights?

My primary goal is to have a true 12 second car. I don't want to go faster than that. I drive me car on the highway and have to be realistic about it.

To keep a little low end torque you need a little back pressure to maintain drivability.

Talk to engine builders and pro racers to get a better insight on this whole exhaust thing. Let not get too crazy for the street.

i didnt say they were too loud, what are super 44's? possibly the next level for me?