I made a mistake,
10-08-2014, 09:35 AM
#1
Senior Member
Thread Starter
Join Date: 04-26-2009
Location: City of Champions
Posts: 666
I made a mistake,
in thinking that a 2.5" exhaust system was ok with an E47 "tune"…
After reading up on some Ethanol articles, I now realize that there
is an increase in exhaust volume, because of the need of more Ethanol
contant, in the E47 "mix".
So, I just put in a custom made, 3" resonator/muffler, in place of my 2.5"
resonator/muffler, to see if it would make a difference.
It did, I've just done a little testing on the street.
At full throttle, it holds my desired 25lb boost.
With the 2.5" resonator/muffler, boost would slowly decrease.
I need to get to the track, to see if there are any gains to be had...
Hmm... Test-n-Tune tomorrow night at my local track.
Temps in the 50s, should get so good runs in...
After reading up on some Ethanol articles, I now realize that there
is an increase in exhaust volume, because of the need of more Ethanol
contant, in the E47 "mix".
So, I just put in a custom made, 3" resonator/muffler, in place of my 2.5"
resonator/muffler, to see if it would make a difference.
It did, I've just done a little testing on the street.
At full throttle, it holds my desired 25lb boost.
With the 2.5" resonator/muffler, boost would slowly decrease.
I need to get to the track, to see if there are any gains to be had...
Hmm... Test-n-Tune tomorrow night at my local track.
Temps in the 50s, should get so good runs in...
Last edited by 2005HHRauto; 10-08-2014 at 02:24 PM.
10-20-2014, 12:38 PM
#2
Senior Member
Thread Starter
Join Date: 04-26-2009
Location: City of Champions
Posts: 666
Yes, I did make it to the track the next day 10/9/14.
Yes, the 3" muffler/resonator did help.
At 1st, when looking at my logs of my runs down the track,
I really didn't see anything that stood out, until I realized that there
was a very slight change in acceleration...
A good night at the track, 6 runs, all in the 12.3s,
with about a 1 MPH better trap speed, compared to when I ran 12.4s,
the last 3 times out at the track last year.
Yes, the 3" muffler/resonator did help.
At 1st, when looking at my logs of my runs down the track,
I really didn't see anything that stood out, until I realized that there
was a very slight change in acceleration...
A good night at the track, 6 runs, all in the 12.3s,
with about a 1 MPH better trap speed, compared to when I ran 12.4s,
the last 3 times out at the track last year.
10-22-2014, 01:50 PM
#4
Senior Member
Thread Starter
Join Date: 04-26-2009
Location: City of Champions
Posts: 666
I'm running a stock 1st cat, with a 100 cell 5" diameter 2nd cat.
Also I still have a, 5"x8" X18" Magnaflow 2.5" ID center/offset, muffler at the back, with a stock HHR SS tip at the end.
A 2.5" ID muffler at the end is ok as the hot exhaust gases have cooled down, alot at that point.
Even though, the stock muffler is a larger, 2.75" ID...
I'm using Magnaflow 3" tubing, between the 2 mufflers.
The 5"x8"x24" 3" ID straight thru, Magnaflow muffler, bolted to the stock DP, has also been modified.
I welded a piece of stainless steel sheet metal, 2.9"x24"x 11 gauge , into the muffler.
This splits the muffler, to create 2 passages, to break up the sound waves.
Sounds good, & it's quiet...
Also I still have a, 5"x8" X18" Magnaflow 2.5" ID center/offset, muffler at the back, with a stock HHR SS tip at the end.
A 2.5" ID muffler at the end is ok as the hot exhaust gases have cooled down, alot at that point.
Even though, the stock muffler is a larger, 2.75" ID...
I'm using Magnaflow 3" tubing, between the 2 mufflers.
The 5"x8"x24" 3" ID straight thru, Magnaflow muffler, bolted to the stock DP, has also been modified.
I welded a piece of stainless steel sheet metal, 2.9"x24"x 11 gauge , into the muffler.
This splits the muffler, to create 2 passages, to break up the sound waves.
Sounds good, & it's quiet...
10-22-2014, 02:38 PM
#5
Senior Member
Join Date: 02-13-2010
Location: HuskerNation
Posts: 698
I'm running a stock 1st cat, with a 100 cell 5" diameter 2nd cat.
Also I still have a, 5"x8" X18" Magnaflow 2.5" ID center/offset, muffler at the back, with a stock HHR SS tip at the end.
A 2.5" ID muffler at the end is ok as the hot exhaust gases have cooled down, alot at that point.
Even though, the stock muffler is a larger, 2.75" ID...
I'm using Magnaflow 3" tubing, between the 2 mufflers.
The 5"x8"x24" 3" ID straight thru, Magnaflow muffler, bolted to the stock DP, has also been modified.
I welded a piece of stainless steel sheet metal, 2.9"x24"x 11 gauge , into the muffler.
This splits the muffler, to create 2 passages, to break up the sound waves.
Sounds good, & it's quiet...
Also I still have a, 5"x8" X18" Magnaflow 2.5" ID center/offset, muffler at the back, with a stock HHR SS tip at the end.
A 2.5" ID muffler at the end is ok as the hot exhaust gases have cooled down, alot at that point.
Even though, the stock muffler is a larger, 2.75" ID...
I'm using Magnaflow 3" tubing, between the 2 mufflers.
The 5"x8"x24" 3" ID straight thru, Magnaflow muffler, bolted to the stock DP, has also been modified.
I welded a piece of stainless steel sheet metal, 2.9"x24"x 11 gauge , into the muffler.
This splits the muffler, to create 2 passages, to break up the sound waves.
Sounds good, & it's quiet...
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