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Is this exhaust to big?

B

bdemutis

Active Member
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Is this exhaust to big that my truck won't have enough back pressure. Today I did all my glow plugs and took the downpipe off and noticed that it's a 3" downpipe but after it connects to the flange it bumps out to a 6" all the way back. It's literally a cannon I never noticed it before until know I thought it was a 4". It bottlenecks from 3 to 6 I never seen anything like that.
a305dec8837274facdffb9a1f5649b13.jpg
 
Jorge6.5 said:
It sure can't hurt, I bet it sounds bad ass!
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It's really droney but I just noticed that it was that big but I have an exhaust leak at the cross over pipes some one did a shabby weld job so I have to get a new cross over because they cut the stock one and dropped it lower to go under the 4x4 shaft. So cross over and next cold air it should sound pretty good
 
Jorge6.5 said:
Get yourself a nice mandrel bent crossover.

Maybe yours was extended for the suspension lift
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Hmm maybe but the weld job is so crappy I mean it looks like they welded it with a mig not using Flux core wire or any gas. If it was extended for that purpose I'll just get the mandral bent one and cut it and mig weld it I just got another new welder I have to test out anyway. But I hope it fits without cutting it.
 
6.5 Diesels don't need back pressure they don't have throttle plates and a turbo negates traditional exhaust scavenging requirements at the HP output levels of a 6.5 td. EXAMPLE: A 3" pipe can flow 850 cfm+- under good boost levels and 740 cfm+- normally aspired, bigger is always better
 
FellowTraveler said:
6.5 Diesels don't need back pressure they don't have throttle plates and a turbo negates traditional exhaust scavenging requirements at the HP output levels of a 6.5 td. EXAMPLE: A 3" pipe can flow 850 cfm+- under good boost levels and 740 cfm+- normally aspired, bigger is always better
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Ok so it's not like a naturally aspirated gas motor. So with a nice air filter it should be awesome.
 
bdemutis said:
They always say that but a new study shows the average male is only 6" o wait wrong thread lol. [emoji38]
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Well I was going to say you need to punch your man card. There are thing never said about trucks:
Those tires are too big for that there truck.
The exhaust is too big for that there truck.
It's too loud. Let the Woman complain about than then 'fix it for her'
 
WarWagon said:
Well I was going to say you need to punch your man card. There are thing never said about trucks:
Those tires are too big for that there truck.
The exhaust is too big for that there truck.
It's too loud. Let the Woman complain about than then 'fix it for her'
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I just thought it needed some back pressure like a gas job. Also she won't complain because she keeps trying to lift her truck higher but she can barely get in it now we had to put steps on it. I wish I still had the 35s I put 265s on lol.
 
I don't think its 6" diameter pipe (from the picture anyway). It looks like a DiamondEye system to me, great system. 6" would never get over the axle (but your truck is lifted so maybe???).
 
bdemutis said:
I just thought it needed some back pressure like a gas job. Also she won't complain because she keeps trying to lift her truck higher but she can barely get in it now we had to put steps on it. I wish I still had the 35s I put 265s on lol.
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No engine needs backpressure, IE diesel or gas and especially turbo engines. Believe it or not, you can go too big, but in this case, it looks like a 4" system and that's fine.
 
turbovanman said:
No engine needs backpressure, IE diesel or gas and especially turbo engines. Believe it or not, you can go too big, but in this case, it looks like a 4" system and that's fine.
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Aside of 2 stroke tuned exhaust, some engines like a 1995 350 require a specific amount of backpressure so the EGR works as designed. These would be the vacuum operated with the exhaust pressure valve in them. When the exhaust pressure valve fails the EGR valve flops wide open just off idle and kills the engine from too much EGR. A less restrictive exhaust results in excessive spark knock under high load due to lack of EGR. Needs a tune to fix.
 
WarWagon said:
Aside of 2 stroke tuned exhaust, some engines like a 1995 350 require a specific amount of backpressure so the EGR works as designed. These would be the vacuum operated with the exhaust pressure valve in them. When the exhaust pressure valve fails the EGR valve flops wide open just off idle and kills the engine from too much EGR. A less restrictive exhaust results in excessive spark knock under high load due to lack of EGR. Needs a tune to fix.
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Correct, if the engine has EGR, if not, all bets are off, :D
 
Correct me if I'm wrong, I seem to remember when building a gas motor for lots of low end torque an exhaust restriction at low rpms helps to increases the torque output.
 
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