Community Forums

CC38EL · 09-30-2021, 10:12 AM

Well, out with the old and in with the new. Had my local muffler guy put the Dynomas Super Turbo in place of the stock muffler. No increase in sound (thankfully) but there is definitely an increase in throttle response and the perception of additional 'quickness'.

Don't have any details yet on hills, grades or mpg. Don't have a trip for a few weeks. When I do, I'll update.

Apparently, no matter what I do, that second photo will remain upside down. Sorry about that.

whem2fish · 09-30-2021, 10:44 AM

Quote:

Originally Posted by 77Travco

Performance testing with a motorhome?.. Your my kind of people! ... LOL

Ask him about his motor

Daveinet · 10-01-2021, 06:57 AM

Quote:

Originally Posted by CC38EL

...No increase in sound (thankfully) but there is definitely an increase in throttle response and the perception of additional 'quickness'.

But loud makes it fast LOL.

Quote:

Don't have any details yet on hills, grades or mpg. Don't have a trip for a few weeks. When I do, I'll update.

While there is a comment about performance testing a motorhome, that is really the only way to know what you got. A zero to 60 test gives you a benchmark to compare. Per my above comment, I can easily be deceived about how quick something feels, when you have a little rumble to go along with it, or when you want to see it better, you can fool your mind into thinking you feel a difference. A stopwatch was always less subjective.

When I was tuning the 502 in the Revcon, I had the advantage of graphing engine RPM over time. So I could sit in second gear with it floored, and see how long it to gain RPM. I couldn't do the test in 1st, because it would just spin the front wheels. Even punching it at 20 mph, it would still light 'em up. The second thing that was interesting is watching the vacuum. Above 4000 RPM, it would start to increase, which means my intake was hurting the flow. I did a lot of experimenting with different intake designs. I ended up with two PVC tubes about 25 inches long, feeding the throttle plate. That gave me the least vacuum drop in the top end. If you can put a reader on it and watch the vacuum, it will tell you if you are loosing power in the top end. Ford was notorious for poor air flow. 1st gen v10 was much worse than the 2nd gen v10.

CC38EL · 10-01-2021, 07:43 AM

When we had diesel MHs, it was always fun to floor it at intersections when competing with cars. Torque always wins....for about 10 feet.

Coming home from the muffler shop this week, I had the opportunity to do the same thing. Before the muffler swap, I would make a lot of noise and fade slowly into the sunset....after, we held our own and kept up pretty good. I know my fuel was taking a hit, but I didn't do the swap for mpg. I sense that this setup will work for us in the mountains better than stock.

I do have a reader and it is setup....but I'm going to have to find the vacuum setting. The app I use gives me about 100 different things and I find 6 of them useful.

Also, I'm at the $$ limit on what I would do to this engine/transmission. I'm not spending $$$ on Banks or a tune as, for me, the ROI isn't there. Not because the value isn't there, but because our time remaining in the RV world is stopping in the next few years. Just wanted to open it up a bit.

THenne1713 · 10-01-2021, 12:19 PM

Quote:

Originally Posted by CC38EL

I've read where several of us have looked at muffler change outs to improve performance and noise and heat distribution. Was wondering if anyone has actually done that on a 2015 or newer F53 chassis.

If you have, what muffler did you settle on? Walker BTM, MagnaFlow, or other?

Our last trip was into the mountains of east TN and west NC. 22K chassis towing 4200lb Cadillac SRX. Going up, it sure seemed like the engine was choking slowly almost like it was restricted (obviously, that is only a seat of the pants feeling, I'm not an engineer).

Going down.....now that was exciting and loud...but perfectly safe with T/H mode.

I'm not looking at a tune or a Banks mod or other tweak. Just looking for muffler information. TIA.

After putting n a temporary bypass after CAT stolen, it is amazing just the difference in airflow volume at tailpipe at idle? Makes me suspect old CAT (42k miles) was failing/ clogged? Did have a history of two cylinders missing when I bought it, which may have been the cause of CAT clog/ (melt?)? Two COPS coils had water damage, for unknown reason?

sibe · 10-01-2021, 01:04 PM

I with this one on my last RV. 8years ago and it is still ok with new owner,, out one on my current RV..

https://www.dynomax.com/super-turbo-...set-18015.html

I can hear it a tad going close to a concrete divider,, I have no Cat as it was not required for my old stead in my state, It is a straight 3" from ypipe to muffler then 2 turns and it dumps infront of tires..
It did not really help fuel miles per gallon but it doese run way better and cooler..

twinboat · 10-01-2021, 03:36 PM

Quote:

Originally Posted by THenne1713

After putting n a temporary bypass after CAT stolen, it is amazing just the difference in airflow volume at tailpipe at idle? Makes me suspect old CAT (42k miles) was failing/ clogged? Did have a history of two cylinders missing when I bought it, which may have been the cause of CAT clog/ (melt?)? Two COPS coils had water damage, for unknown reason?

Where was the air flow going before the change ?

The throttle controls the air going into an engine. More air, more RPMs.

THenne1713 · 10-01-2021, 11:01 PM

Quote:

Originally Posted by twinboat

Where was the air flow going before the change ?

The throttle controls the air going into an engine. More air, more RPMs.

I can only assume into "backpressure", partially, but not completely clogged? Just putting your hand at tailpipe, tremendous difference in idle airflow, and much cooler when CAT was there?

Amazing CAT glows red in the youtube with PROJECT FARM, ever see it? Demo is using Small engines w/ CATS honeycomb attached.

Daveinet · 10-02-2021, 07:49 AM

I could not find the video you are referring to, but I would be careful inferring too much from a video like that. The ECM in your car is specifically designed to feed that cat. They toggle the mixture back and forth from rich to lean. The spurts of rich mixture send fuel down the exhaust to feed the cat so it stays hot enough to burn off the unburnt fuel. There is always some amount of unburned fuel in the exhaust, but that is not enough to get the cat hot enough to burn it off. By dumping small spurts of fuel into the exhuast, it stays hot enough to burn off all the extra unburnt fuel, this reducing emissions. GM actually got in trouble with the EPA in the early 90s for creating a lean burn mode for fuel economy. There was a delay in turning on the mode, so that it would not be sensed by the EPA tests. The problem was that it did not feed the cats, so there was increased emissions. GM went back and disabled the feature once they were caught. Tuners like that model ECM, as it is very easy to enable it again. There are ways to make the later ECMs to simulate that mode, but only ECMs prior to '92 had it.

I suspect if the cat was glowing in the video, the engine was running richer than designed. Having said that, under severe load, the ECM will go into a self preservation mode and dump extra fuel in the engine to cool it down. This mode may put enough fuel into the cat to make it glow. But its not just the engine heat that makes it glow, but rather a rich mixture.

THenne1713 · 10-02-2021, 11:12 PM

Davinet, I recall reading a MSDS on CO, about 10yrs ago, seeing where it said HAZARD: FLAMMABLE/ COMBUSTIBLE GAS or similar, thinking "I had never thought of CO as flammable gas before".... thinking all combustibles already burned, I guess... not so much :-)

THenne1713 · 10-02-2021, 11:26 PM

Found this:

https://www.youtube.com/watch?v=ekQcy6GN1pM&t=397s

donr103 · 10-10-2021, 08:03 PM

Glaspacks are easily changed out.. when fiberglass burns out.. can be done at home.. in short time.. also use ss slip clamps and job is mins.. but like opinions there are just as many mufflers.. so experiment get balance of back pressure and sound that you are comfortable with.. it's your coach.. enjoy
As always good luck and let us know what you did and maybe better members then me will help.. love the pictures by the way.. good job.. maybe others will catch on.. but with rv.. usually last thing anyone thinks about.. until there is a problem.. too bad..

CC38EL · 12-06-2021, 08:58 AM

So, after installing the new muffler, we took off for the winter. Going east to west, we encountered 6% grades and headwinds. We're limited to 65mph because of the toad.

I can tell you that it is well worth the change out. Our throttle response was much improved. Even my wife who really doesn't notice stuff I do to the vehicles noticed it was much much better than when we went to the mountains of NC. Our at the top speed was much improved, on ramp speed ups were great, and passing was a lot less dramatic.

Power felt great (perception, not fact). MPG improved about .5 over NC trip and that was going into headwinds.

All in all, very happy.

THenne1713 · 12-07-2021, 12:20 AM

Since O2 sensor (thru the computer) affects INJECTOR/ MIXTURE, IMHO it is a WASTE of time to TRY to run without O2 sensor in stream to "check for performance change/ improvement", when ACTUAL will be so much different w/ sensor in use and Mixture where it belongs in range? About as worthless as disconnecting two cylinders on a V-8 to see how a six cylinder might run?