flowmaster upgrate = power loss ?

**hit747** · 09-15-2009

I have a 07 GP GXP, today i installed flowmaster 40's. After the installation the car feels more sluggish and dose not have that kick of power anymore. Is the engine chocking? What can be the problem? Plz help bcuz the car realy feels a bit weaker.

**BwolfGT** · 09-15-2009

Is that just mufflers or a full exhaust? Mufflers shouldn't change anything, but if an exhaust is too big there will be no back pressure and you'll lose power.

**hit747** · 09-15-2009

Its just the mufflers. I know it sounds weird but when you rev it and let go and immediately rev it again it sounds and feels like the 2nd rev is much weaker and the engine struggles with it. Same thing on the freeway when you floor it it dosent throw you back into the seat as much as it did before the install

**skidoojames151** · 09-15-2009

well then put the stockers back on and see if that fixes it...they sound the best anyway

**blueguy** · 09-15-2009

^^It's a GXP...they sound better with aftermarket muffs anyways IMO. V8...

Just cut them off...that way there is NO muffler...at least that is what I would do...and it is free

**skidoojames151** · 09-15-2009

ah yea didnt see that, and agreed with the no mufflers...V8's are sexy without muffs...

**PowerStroker** · 09-17-2009

From my personal experiences, I have noticed the same problems with putting Flowmaster mufflers on any of my cars/trucks (except my 98 Z71). Their mufflers are built to support a bigger small block and big block apps. With all the new BS that's integrated on these new V8's, the back pressure is dropped at some point in the system.

I don't know a lot about the new GM V8's but I know that what I see more than anything on the 5.4L Triton V8 (Ford) is Magnaflow and Borla. Flowmaster is on its way out as far as I'm concerned.

Don't know if it helps at all, but I don't want to make you feel bad

**GTPJOE90** · 09-17-2009

flowmasters suck on our cars..... stop wasting money

**Bio248** · 09-17-2009

Originally Posted by GTPJOE90

flowmasters suck on our cars..... stop wasting money

did you read anything? its a GXP. itd sound good with no mufflers so i bet it wounds good with flowmasters too.

**dagger** · 09-17-2009

I have flows on my 01 GTP and I didn't feel any kind of power loss and they sound good. Raspy at high RPMS but thats because of the engine, I'm going to get a better resonator to try and help that.

**sasquatch094** · 09-18-2009

Flowmasters were proven to lose horsepower on tons of shows and such.. no mufflers tho, lost more horsepower then with the flowmasters on..

**PowerStroker** · 09-18-2009

Originally Posted by Bio248

did you read anything? its a GXP. itd sound good with no mufflers so i bet it wounds good with flowmasters too.

I think the "suck" he was talking about was performance-wise, not sound-wise. Why would you spend money on exhaust for sound? I thought this forum was all about performance?

Sasquatch lost power with straight pipes due to loss of back pressure. Stock exhaust is fine on these cars. Why straight pipe a small V8? Much less a larger V6 with mufflers? No benefit comes with it in my book. Just money spent you'll never EVER see again when you sell it...