Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: dans96u295ft on July 22, 2020, 12:07:41 pm

Title: muffler change today
Post by: dans96u295ft on July 22, 2020, 12:07:41 pm
Getting the trash can muffler replaced with a straight thru resonator today. Buddy of mine who knows his diesels, says 7 lbs of back pressure will keep the torq values peaked so I am having him add the resonator. I'll report back on driving and noise fun!
Title: Re: muffler change today
Post by: kimosabe99 on July 22, 2020, 12:40:07 pm
Post a few photos if you can.

jk
Title: Re: muffler change today
Post by: jor on July 22, 2020, 12:58:57 pm
Quote
Post a few photos if you can.

I second this. It's fun to see the different approaches to this deal.
jor
Title: Re: muffler change today
Post by: bigdog on July 22, 2020, 01:07:21 pm
Along with pictures. Have your lovely assistant positioned in the back with a cell video going on the way to and from the shop. I.E. A before and after. (if it's not to late)
Title: Re: muffler change today
Post by: dans96u295ft on July 22, 2020, 02:46:33 pm
To late. I walked home. My lovely assistant was on a conference call. Ha Ha
Title: Re: muffler change today
Post by: Caflashbob on July 22, 2020, 02:55:12 pm
Yes a certain amount of back pressure is helpful
Title: Re: muffler change today
Post by: Twig on July 22, 2020, 03:07:07 pm
What model resonator? I might do the same.
Title: Re: muffler change today
Post by: bigdog on July 22, 2020, 04:07:05 pm
To late. I walked home. My lovely assistant was on a conference call. Ha Ha
You better take your assistant with you to pick it up and record the sound. Or we will toss wet Rigatoni at you. :))  :))
Title: Re: muffler change today
Post by: dans96u295ft on July 22, 2020, 05:04:42 pm
Ok. Soon as I hit the key, I could hear the turbo spool up and spool down . Soon as I pulled into the 45mph lane I felt more torq! It is still quiet but you can now hear the Cummins turbo. Sounds a bit nasty to be frank! Campgrounds won't know the difference. Next trip pulling hills I know, I'll report back. I'll post pictures soon! He had to cut all the old out from corrosion (hangers, bolts, clamps). $500 well spent. I'm up for hernia surgery so couldn't do it myself anyway. Highly recommend it!
Title: Re: muffler change today
Post by: Tim Fiedler on July 22, 2020, 05:06:29 pm
You will adjust quickly. It will become the new normal
Title: Re: muffler change today
Post by: Caflashbob on July 22, 2020, 05:15:50 pm
Noticeable torque increase.  Even more if you have the correct hydraulic fan controller versus my oem sucked 50 hp when the motor was warmed up every time
Title: Re: muffler change today
Post by: dans96u295ft on July 22, 2020, 07:38:25 pm
Try pics again
Title: Re: muffler change today
Post by: bigdog on July 22, 2020, 07:46:05 pm
I hope that hanger isn't solid mounted from the rez to the frame above. Shouldn't it have a vibration isolator of some sort. Or am I just not seeing it?
Title: Re: muffler change today
Post by: dans96u295ft on July 22, 2020, 07:55:37 pm
It's rubber supported at the mount but there are 3 hangers. I'll keep an eye on it. Thanks
Title: Re: muffler change today
Post by: bigdog on July 22, 2020, 08:33:39 pm
It's rubber supported at the mount but there are 3 hangers. I'll keep an eye on it. Thanks
Ok, I just wasn't seeing it.  ^.^d
Title: Re: muffler change today
Post by: John44 on July 22, 2020, 08:47:26 pm
Some in the past have found the old muffler full of carbon,how does yours look?
Title: Re: muffler change today
Post by: dans96u295ft on July 22, 2020, 11:38:34 pm
I didn't look as my muffler shop did the work. I saw it laying there and didn't say goodbye to the beast!
Title: Re: muffler change today
Post by: dans96u295ft on July 23, 2020, 09:52:58 am
Forgot, My idle cam up appx. 200 rpm's as well. Old muffler had 125,000 on it and must have been partially plugged with carbon
Title: Re: muffler change today
Post by: wolfe10 on July 23, 2020, 10:19:25 am
Forgot, My idle cam up appx. 200 rpm's as well.

You need to have the idle speed set back to factory spec.

Your idle speed may be approaching the RPM where the Allison will not go into gear (to protect itself).  If this happens the shift pad will just flash when you try to put it in gear.
Title: Re: muffler change today
Post by: dans96u295ft on July 23, 2020, 10:30:25 am
Good to know. I believe in gear, 750 rpm is spec on the 8.3, I'll look it up. Thanks for the tip