Flowmaster upgrade on my Hummer H3
#1
08-23-2010, 01:55 PM
Flowmaster upgrade on my Hummer H3
Hey all, I just wanted to share with you my recent exhaust upgrade on my 2007 Hummer H3 (3.7 5-cylinder).
I was unhappy with the stock HP of the H3 with poor take-off and acceleration, so I looked into ways of increasing HP with minimal costs. First, I upgraded the stock air filter with a K&N brand ($50) from my local AutoZone. I did not get any noticeable gains from the new ait filter. Next, I added a Tuner GT+ chip ($10 on eBay) to the MAF sensor. I noticed a slight increase in acceleration from the chip, but I did not notice any improvement in gas mileage from the chip. I still was not satified.
After doing some extensive research on exhaust systems, I decided to purchase a Flowmaster Super 44 muffler ($90 on eBay) for my H3. I brought it to my local Big Al's Muffler Shop and paid $150 out-the-door for labor and parts. I had them cutt off the resonator, and put the Flowmaster in its place. I had purchased a muffler with an offset, same-side inlet/outlet configuration so it would clear the drivetrain okay. I had the stock "suitcase" muffler completely cut-out and removed, and re-routed the tailpipe to exit strait out the back on the passenger side. The tailpipe points down slightly to direct exhaust downward.
I noticed a definite HP increase with the new hi-flow muffler and strait pipe design. It had a nice rumble at idle and a mean growl on acceleration. I estimate an improvement in gas mileage by 1-2 mpg depending on my driving. I may have lost some low-end torque due to the decreased back-pressure, but it is a trade-off for the increased HP and improved gas mileage.
I had one issue that almost ruined the exhaust upgarde for me: I had a horrible exhaust drone at about 2000 rpm, which is my typical cruising rpm on the highway (60 - 70 mph). It was an unpleasant hum from my exhaust that eveloped the entire cabin of my H3, and it was unbearable for me on extensive roadtrips. I thought maybe I could live with it and find ways to drive around the drone; but since I normally drive around 60 - 70 mph, it was pretty much unavoidable. Or, I thought maybe there would be a break-in period for the muffler to mellow out. But a metal, chambered muffler has no real break-in period. Some posts say that a gradual build-up of carbon in the muffler with mellow the sound in time, but I'm not sure if that is true.
Solution: I bought an inexpensive, bolt-on, chrome resonating exhaust tip from Wal-mart ($12). It is about a foot long from end-to-end. I attached it to the end of my tailpipe and the DRONE IS GONE!! It also gave me a richer, deeper idle sound. And, now it purrs at acceleration instead of an obnoxious growl. It sticks out about 3" past my bumper, and looks nicer than the plain tailpipe. I couldn't be more happy.
I believe it was a worthwhile upgrade for a relatively low cost.
I was unhappy with the stock HP of the H3 with poor take-off and acceleration, so I looked into ways of increasing HP with minimal costs. First, I upgraded the stock air filter with a K&N brand ($50) from my local AutoZone. I did not get any noticeable gains from the new ait filter. Next, I added a Tuner GT+ chip ($10 on eBay) to the MAF sensor. I noticed a slight increase in acceleration from the chip, but I did not notice any improvement in gas mileage from the chip. I still was not satified.
After doing some extensive research on exhaust systems, I decided to purchase a Flowmaster Super 44 muffler ($90 on eBay) for my H3. I brought it to my local Big Al's Muffler Shop and paid $150 out-the-door for labor and parts. I had them cutt off the resonator, and put the Flowmaster in its place. I had purchased a muffler with an offset, same-side inlet/outlet configuration so it would clear the drivetrain okay. I had the stock "suitcase" muffler completely cut-out and removed, and re-routed the tailpipe to exit strait out the back on the passenger side. The tailpipe points down slightly to direct exhaust downward.
I noticed a definite HP increase with the new hi-flow muffler and strait pipe design. It had a nice rumble at idle and a mean growl on acceleration. I estimate an improvement in gas mileage by 1-2 mpg depending on my driving. I may have lost some low-end torque due to the decreased back-pressure, but it is a trade-off for the increased HP and improved gas mileage.
I had one issue that almost ruined the exhaust upgarde for me: I had a horrible exhaust drone at about 2000 rpm, which is my typical cruising rpm on the highway (60 - 70 mph). It was an unpleasant hum from my exhaust that eveloped the entire cabin of my H3, and it was unbearable for me on extensive roadtrips. I thought maybe I could live with it and find ways to drive around the drone; but since I normally drive around 60 - 70 mph, it was pretty much unavoidable. Or, I thought maybe there would be a break-in period for the muffler to mellow out. But a metal, chambered muffler has no real break-in period. Some posts say that a gradual build-up of carbon in the muffler with mellow the sound in time, but I'm not sure if that is true.
Solution: I bought an inexpensive, bolt-on, chrome resonating exhaust tip from Wal-mart ($12). It is about a foot long from end-to-end. I attached it to the end of my tailpipe and the DRONE IS GONE!! It also gave me a richer, deeper idle sound. And, now it purrs at acceleration instead of an obnoxious growl. It sticks out about 3" past my bumper, and looks nicer than the plain tailpipe. I couldn't be more happy.
I believe it was a worthwhile upgrade for a relatively low cost.
#3
08-23-2010, 05:39 PM
#4
08-23-2010, 06:26 PM
#5
08-23-2010, 09:36 PM
I'm getting about 25 more miles on a full tank of gas with mixed city and highway driving. I have yet to take it on a road trip to see how far I can get on all highway driving, but I imagine I may be able to squeeze out another 25 miles. The engine definitely seems to be under a lot less strain, and it rides ultra smooth at high speeds (over 75 mph). And, I have to lighten up on the gas pedal a bit because it's easy to speed without realizing it. My engine seems much more responsive, and she takes off the line pretty quickly now.
Thread
Thread Starter
Forum
Replies
Last Post
iqbal
PRIVATE For Sale / Trade Classifieds
4
02-28-2011 02:47 PM
07HummerH3
PRIVATE For Sale / Trade Classifieds
17
09-11-2009 12:53 PM
shawnnlivier
PRIVATE For Sale / Trade Classifieds
9
11-16-2006 02:27 PM
