4" vs. 3" straight pipe

[MOstrowski]

Is a 4" exhaust w/o muffler any louder than 3" straight piped?



My 93 currently has a 3" straight pipe, which was fine when the sound only came out the tail pipe, but its a tiny bit loud lately with all the holes in the system. I plan on going with the 4" parts that I need from bigexhaust.com and was debating wether or not to get a muffler.



thanks to all who reply,

Michael

 

[MGosciewski]

Although my 3" stock system didn't have holes, I am pretty sure my current 4" straight pipe is louder than my 3" would have been with a muffler delete.



Does this bigexhaust.com have a way for me to get over the rear axle with my current custom system that dumps underneath?

 

[MOstrowski]

Does this bigexhaust.com have a way for me to get over the rear axle with my current custom system that dumps underneath?

Yes, they have complete systems available or just individual parts in the shopdiesel performance exhaust line. Not sure about the other brands.

 

[pepecat]

I think it is louder for 3" than four, I have herad tkingsbury's 3"

but I think in cab a 3" system that dumps out in the front of the rear wheel is louder than 4" all the way back

try it without muffler first, then add one on later, like a high flow donaldson

 

[MGosciewski]

Yes, they have complete systems available or just individual parts in the shopdiesel performance exhaust line. Not sure about the other brands.

Hey up there in the Lansing area! Yeah, I checked out shopdiesel and sure enough they break down the exhaust system so that I can just buy the tailpipe. Man, thanks, I learned something again off this forum. Instead of my 6" tip coming out and sooting the rear rim I can get it out the back corner. Right now it just shoots straight back... it's hidden, but it sure isn't silent!!! :-laf

 

[CHolman]

Muffler

I got a muffler from big exhaust.com "their muffler" when I got their 5" system and it sounded bad... I ordered a replacemnt stright pipe and was :-laf after that... I wouldn't get that muffler.

 

[JLEONARD]

I got my 4 inch system from Janetty. . it was "standard" paarts put together to make a kit.

The muffler was an Allied as I recall. Long sucker. Has an ok tone, but I can't hear it in the cab over the engine noise and no drone on the highway... all things that I wanted along with the performance gains... 3 psi boost, quicker spoolup, etc.

Jay

 

[Greenleaf]

Jay,



That a TOTAL of 3 psi boost to accompany that 15 RWHP?

If I'd order the Janetty kit for say a 300 hp engine, do they auto upgrade that "Standard" to the 6 inch system?

I didn't know ISSPRO made an Exhaust Temp Gauge that reads under 100 °F



I'm through for now... .

 

[hotram03]

What do these trucks have factory, and does it help the truck if you straight pipe the factory system? As far as spool up and fuel mileage?

 

[TKingsbury]

1st gens have 3" pipe stock. I think a straight pipe can only help with efficiency. The stock tailpipes do have some nasty bends though. I put a stock tailpipe off of an 01 24v on mine, it has less and smoother bends than the stocker. It also tucks up ender the bed better and has a better looking tip.

Travis. .

 

[tugboatphil]

Jay,

That a TOTAL of 3 psi boost to accompany that 15 RWHP? I didn't know ISSPRO made an Exhaust Temp Gauge that reads under 100 °F

Scott,



Quit it! You're killing me! :-laf :-laf Let up already!

 

[Sled Puller]

I think straight 4 has a bleating sound, straight 5" all the way back has a nice roar. Straight 3 sounds normal.

 

[MGosciewski]

I got a muffler from big exhaust.com "their muffler" when I got their 5" system and it sounded bad... I ordered a replacemnt stright pipe and was :-laf after that... I wouldn't get that muffler.

Muffler on my Cummins???? NO WAY!!

 

[BushWakr - RIP]

One thing I discovered when changing my exhaust system was that the "loudness" was noticably different when using a turn down tip as opposed to a straight cut tip.

In town the the straight tip just bounced the noise off the buildings like crazy. This did not happen near as much with a turn down tip.

The up side of this is that the turn down tip directs the exhaust noise AND the exhaust smoke downward to the pavement.



Just a thought... .



pb...

 

[TKingsbury]

One thing I discovered when changing my exhaust system was that the "loudness" was noticably different when using a turn down tip as opposed to a straight cut tip.

In town the the straight tip just bounced the noise off the buildings like crazy. This did not happen near as much with a turn down tip.

The up side of this is that the turn down tip directs the exhaust noise AND the exhaust smoke downward to the pavement.



Just a thought... .



pb...

Good point, I noticed this too. When my tailpipe was broken off just behind the rear axle and pointing back/down it was very liveable. Then I welded the tailpipe back together, WOW it was loud, especially in my neighborhood where it bounced back off of houses. When I put on the 24v pipe, the tip angles down and back a bit so the noise (at least what I hear) is minimized.

Travis. .

 

[JLEONARD]

I'm through for now

Quit it! You're killing me!

Ok youse guys... have your fun now at my expense... . but once we meet on the street... ..... it's no more mister nice guy for me baby!!!! Your turbo will be gaggin' on my smoke!!!! All 15. 6 horsepower of it.



Jay

 

[DKasper]

I'll echo PB on this one -- my D350 w/turndown has much less percieved volume -- by people who have heard both of mine -- than my w350 with just an open end. I think the turn-down sounds better.

JMO



Dave

 

[Greenleaf]

LOL You guys. You otta try two short stacks terminating @ the top of the rear window.

 

[DKasper]

Hey Scott -- what was that you said??



I'd need a hearing aid for sure after driving that setup!