Entire exhaust off, Any engine damage?

[BarlowCummins]

Here is one for ya guys. I took off my cat today and took the rest of the exhaust off as well (except the down pipe). I will be getting a 4 inch piece welded in where the cat was tomarrow. Could there be any damage to the engine or turbo if I drove it around for the night? I'm not sure how much back pressure plays in a cummins. But I have heard that for gasers it could cause pistion ring failures. Any help would be helpful Thanks, Corey

 

[keimmmo]

I see no problem except for the noise and exhaust fumes under the cab. Make sure the exhaust isn't hitting anything that could cause a fire or be damaged by the heat. It won't hurt the motor or turbo a bit.



I have never heard of a lack of backpressure causing ring damage on gas motors. If you were to run the motor right off the heads for any length of time with no manifolds at all, it can damage the valves. If you have ANY kind of manifold or headers on it, it won't hurt a gas motor either.



Steve

 

[jwilliams3]

No damage, you could run it like that forever with no ill effects.

 

[Tomeygun]

Here is one for ya guys. I took off my cat today and took the rest of the exhaust off as well (except the down pipe). I will be getting a 4 inch piece welded in where the cat was tomarrow. Could there be any damage to the engine or turbo if I drove it around for the night? I'm not sure how much back pressure plays in a cummins. But I have heard that for gasers it could cause pistion ring failures. Any help would be helpful Thanks, Corey

I did it for 3 days while waiting for the rest of my system...



Only ill effects would be tke insulation that is now hangs down because I think the heat made it loose its stiffness



Ears still ringing though...

 

[JUeckert]

years ago i put a banks turbo on a gmc with a 6. 2 in it,drove it around for a entire weekend waiting for the muffler shop to open on monday so they could build me a set of 3" straights,anyway the 2' long down pipe was all that i had on it the whole weekend,sure sounded sweet. 12 years and 300+k later shes still hammering.

 

[nickleinonen]

i had the exhaust in my 6. 5td tahoe dumping like that for months [although, i made a turn down to direct most of the exhaust down to the road]. but for a few days or weeks, just straight DP dumping will be fine. .

 

[RJPotts]

I agree, diesel engines need zero backpressure. And if they did, the turbo would make all the necessary backpressure. As stated by others, the only bad thing could be the heat of the exhaust getting to things it shouldn't touch. Otherwise, you're good to go.

-R. J.

 

[NDanecker]

I was told on a gasser you want some back pressure to help build the pressure differential thus spinning the turbo. Not having this back pressure causes the turbo to spin higher RPM's to achieve max boost. I don't see how a diesel is any different. Most turbo’s max out around what, 80k rpms???



Other thing to worry about is exhaust temp. The floor board is probably going to be REALLY HOT!!!



Personally, I’d drive it only what you need to get to the shop and take it easy.



Enjoy your new exhaust!!!

 

[nickleinonen]

Most turbo’s max out around what, 80k rpms???

it all depends on size... you get a small one from a gasser and it can be double that... our stock ones top out about 120k... [the ones i work on at work top out at 20k]



back pressure on any turbo application is not wanted... the turbo is a pressure/heat engine... the greater pressure differential across the turbine, the more speed it can turn and the faster it can get up to speed... that is why opening up the exhaust side of a turbo engine helps spool up so much

 

[RRoton]

On gassers (without a turbo) you will damage valves.



I don't see how you could cause any damage on any engine that has a turbo.

 

[JeepinDoug]

On gassers (without a turbo) you will damage valves.



I don't see how you could cause any damage on any engine that has a turbo.

That's true with shorty headers or exhaust manifolds. The cam timing is scavanging and pulling small jets of cold air back into the exhaust valvewhile the valve is still hot.

You'll notice blown dragstsers with short open headers (zoomies) don't suffer from this because the cam timing is ground with no overlap (no scavanging) and they have a huge air compressor pushing air through the engine.

 

[sootgrinder]

The B series Cummins in our sprayer (5. 9 L) Just has about 2 ft of stack coming off of the Turbo. No problems.