The Stovebolt Site Forums The Shop Area Engine Shop Fentons Sound Lousy!

I just finished installing Fenton exhaust headers with 2 inch pipes running all the way to the rear. It's a 216 with original intake and carb. When I let off the accelerator, I get an annoying "bbrrraaaaappp!!!!" sound as the exhaust pressure drops. I tried the straight pipe approach first, and have read on the forum some guys prefer this. Now, my question is what type of mufflers to install to get that pleasing rumble I've read about but never experienced. Thanks.

Ummmm I thought that WAS the desired effect!!????

I have Flowmasters on my setup but first is the noise you hear backfiring?

Not this, it is down right annoying. I'm hoping to get a pleasing rumble similar to a Harley sound, if possible. Glass packs? Smitty's? Flowmaster? Any good advice is appreciated and hopefully I can do this right the first time!

An inline six is never going to sound like a V twin no matter what you do. Also exhaust sounds are so subjective it really gets you little in discussing them unfortunately. It is something you need to hear and then ask the owner what he has if you like or even if you don't so you don't go that way with yours.

I remember the old Chevy school buses we had when I was in school (40's-50's) and they all had straight pipe completely to the rear. They had what I think is that unmistakable old GM Inliner sound.

Best of luck on this really difficult subject.

I don't think so, but not sure I know the difference. A lot of popping sound during deceleration. I get the same annoying sound at around 50mph. If it helps, the stock setup ran just fine with good throttle response, acceleration, and no backfiring.

I had the same generic glaspaks put on my Suburban as I had installed on the '56 with a 350. I love the sound of the '56 but on the burb they were too loud, as you describe. I added a pair of Walker mufflers near the outlet of the pipes and I love the sound.

My theory is the long section of pipe after the first set allowed the noise build up. I'd suggest putting what ever you use near the end of the run.

You engine doesn't have enough cam shaft or compression to make a lot of deep rumble sound, so pick a mid priced turbo type muffler and call it good. The hollow Flowmaster type muffler isn't going to sound much better. Look into some Dynomax mufflers, they absorb the noise yet still flow great.

Joe

I can't speak specifically to a 216 but the condition you mention is common with motorcycles that have had high flow exhaust installed without also adding a larger jet to the carb. The cause on a bike is a lean condition. I suspect it's the same issue with your truck. Restrict the exhaust or up the fuel input and your popping might go away.

A short read on the issue I referred to.

Well for example there is this and it
Sounds good to me

Lot's of info here and here.

I used a pair of Walker mufflers for a CJ-7, they're fairly quiet. Actually, a little too quiet for my tastes.

Thanks guys for all the insight; especially Cletis for the links to previous discussion on this issue. This is something that obviously is very subjective and there are a number of ways to approach it. Does anyone have any experience with my setup (216, stock intake, fenton exhaust, 2 inch pipes all the way to rear, 4 speed)with Smithy mufflers. I've been told this was the most popular choice "back in the day.". The Smithy's are 30 inches long. The Walkers Cletis likes are 20 inches long. I assume they'll be a little louder than the Smithy's.

I did have the backfiring issue really bad when I installed my exhaust. Adjust your fuel mixure a little and it will help.

Are your pipes joined at any point to help equalize them? I did this to mine on the 235 and frankly I think it may have contributed to the quiteness of the setup.

That "brrrrraaaaaaaaaap!" is the sound your set up makes, and the sound that guys liked back then. I had the same set up as you on my 1 ton, changing to dual intake made no difference. I had 24" cherry bombs on the truck. If you don't like the brap, then actual mufflers is what you want, as has been suggested. I like that brap!

Back firing on deceleration can be reduced by making the idle mixture more rich. But, the truck will still be louder with glasspacks than with mufflers.

Inliners Int Minden NV Chapter has a show "Rappin to Minden" judge vehicles and award trophys to the best RAPPIN pipes. Was the Natl Club's convention this year, had a ball. I'll try to attach a link to contest.

I did not use a muffler on mine I used a resonator on mine.

I used a resonator (Glass pack)about 3" from the first bend and 6" from the resonator I used a Hush Thush muffler. I don't know if you can still get the Hush Thush, it sounded kind of deep and low. Later I moved the exaust just in front of the rear tires. It got louder, but seemed to sound the same. Good luck

Cletus-wake up!

On a stock '54 235 I put a set of Smith-Rieser pressed steel headers (just a sheetmetal version of a 'vette exhaust manifold). This was in 1961-2. I used a stock tail pipe, slightly bent to suit, for the dual side. The header end was 2" dia, the tail pipes were !-7/8"(?). I used the long Smithy steelpaks (under the front seat)L_O_U_D! when in the Raaap mode they could break glass it seemed. Later went to some oval glasspaks (douglas (?). A lot nicer(meaning quieter). After inital installation, I had to change the idle mixture in order to start it (no main jet change was necessary). When backing off it had a pleasant "rack-back" with random popping. The quietness of the mufflers did not affect these characteristics-just the loudness of them. To me stock mufflers were 'way too quiet, for all the hacksaw/welding work, I wanted some noise!

If you are old enough to remember the first of the emissions cars with smog pumps on the stick shift models (1968+), the V8s would really sound bad with loud pipes when you backed off- the super lean stuff (which was a controlled vacuum leak) with retarded timing really messed with the exhaust sound when compared to the '67 models which were still rich and smoggy, but sounded right (the way God intended Chevys to sound).

A crossover pipe will just about wipe out the good split manifold sound - if it is a split manifold with a welded up plate seperating the manifold into two seperate chambers, a small (1/4" dia hole) will cut down on the harshness of its sound, it will tend to sound more like a 6 cyl Porsche's growl. Not bad but not the classic split manifolds sound that we all loved to hear in a tunnel!!!

I think the length of the tail pipe determines the "rackback" and popping on decelleration. Split manifold chevy ll's(mufflers under the BACK seat=short tailpipes) did not rack back with the vigor of the longer piped predessors.

Had a 250 '67 pickup with Hedmens and two flowmasters-wow. It had a snarl due to the collectors with very short (in front of short wheelbase rear tires)tailpipes. Really a slap yo' face sound-almost had an aluminum flywheel abruptness, you could really make the pedestrians jump when you went by them with a little blip of the throttle! Of course, the car alarms in a parking garage were fun too! I was the king of pipes in a tunnel.

Have personally removed glasspaks from a very pleasant '56 265 V-8 and put them on a'52 216 chevy and got tickets the first night out (the old split manifold strikes again).

Its all really trial and error, and these are my results over the years, I hope this kinda sets you in the right direction.

Edski