hole in downpipe

[Kprime911]

i have this big hole on my downpipe and i was wondering would this effect performance? since i got the hole my car has been running pretty slow.

thank you

 

[Spooling99]

Well im not sure how much but I bet that it will effect your performance a little. If your car seems like its running slower then normal i'd also peform a boost leak test. Good luck.
-ADAM-

 

[Blitzeclips]

Be VERY careful about this problem. My buddy had an exhaust leak in his Pontiac Grand Prix. It seemed fine for about 3-4 weks, but afterwards the transmission eventually gave out on his. The Exhaust gases were heating up the tranny, causing it to wear and damage much quicker and aggressively. He had to replace the tranny, and exhaust.

This may depen on where the leak is. Are the gases shooting torwards any mechanical parts, or at the ground?

 

[No_Skillz]

Be VERY careful about this problem. My buddy had an exhaust leak in his Pontiac Grand Prix. It seemed fine for about 3-4 weks, but afterwards the transmission eventually gave out on his. The Exhaust gases were heating up the tranny, causing it to wear and damage much quicker and aggressively. He had to replace the tranny, and exhaust.

Other than this scenario, you will have absolutely no performance problems with a hole in your downpipe. It might actually increase performance by increasing exhaust flow. (You might boost creep, but that's more of a problem uncovered by your hole, not caused by it.)
Keep in mind this is for the vehicle in your profile. If this is about an N/T then it's a whole different story.

 

[xveganxcowboyx]

Other than this scenario, you will have absolutely no performance problems with a hole in your downpipe. It might actually increase performance by increasing exhaust flow. (You might boost creep, but that's more of a problem uncovered by your hole, not caused by it.)
Keep in mind this is for the vehicle in your profile. If this is about an N/T then it's a whole different story.

I disagree. A hole along any section of the exhaust will induce turbulence which will result in back pressure which will hurt performance. How much I can't say, but exhaust leaks do not help performance.

 

[fastalon82]

I however completely agree with skillz. More flow=More power. Simple. But lets not start a pissing match.

 

[Blitzeclips]

Other than this scenario, you will have absolutely no performance problems with a hole in your downpipe. It might actually increase performance by increasing exhaust flow. (You might boost creep, but that's more of a problem uncovered by your hole, not caused by it.)
Keep in mind this is for the vehicle in your profile. If this is about an N/T then it's a whole different story.

I disagree as well. Let's think about this a little further. You say it doesn't fit my vehicle profile and it's a different story. OK, but let's think about the exhaust difference in N/T vs. Turbo..... ready.... NONE. It may help if you opened up a system for turbo's because they are morely exhaust dependant. In this case, it would actually lose backpressure (which is needed more then N/T) therefore loss of power.

Regardless, all performance exhaust systems are dependant on exhaust velocity. If you decrease this, you will cause an imbalance in the exhaust cycle. If a hole in your exhaust created more HP, why havent we seen exhaust systems sold in aftermarket with holes in them? (okay, so there are cut-outs avaiable, but let's not go there...) You want a smooth, fast flowing exhaust...

It may be a boost leak. But once again, I'm going to disagree. A boost leak would benefit torwards NOT blowing a hole in the exhaust. Why would something that decreases HP and pressure within the engine CAUSE something like that? Doesn't add up...

 

[fastalon82]

Okay, he said hole, not leak. If there were a leak this would increase turbulence and slow the flow of exhaust however, if there is a HOLE like described then this would serve as the release point of most of the exhaust and being that its in the downpipe it would relieve most of the restriction of the rest of the exhaust. And since turbo cars dont need backpressure this would benefit greatly.

 

[No_Skillz]

OK, but let's think about the exhaust difference in N/T vs. Turbo..... ready.... NONE. It may help if you opened up a system for turbo's because they are morely exhaust dependant. In this case, it would actually lose backpressure (which is needed more then N/T) therefore loss of power.

There actually is a big difference. Backpressure is important for an N/T at lower rpms. Backpressure is not needed for a turbo. The more flow the better.

Regardless, all performance exhaust systems are dependant on exhaust velocity. If you decrease this, you will cause an imbalance in the exhaust cycle. If a hole in your exhaust created more HP, why havent we seen exhaust systems sold in aftermarket with holes in them? (okay, so there are cut-outs avaiable, but let's not go there...) You want a smooth, fast flowing exhaust...

Nothing is smoother and faster than an open header. That is basically a giant hole. Exhausts are not sold with holes in them because they are harmful to the environment and illegal. You mention cut-outs... and we should certainly go there because the purpose for one is exactly what we're talking about. In racing, exhausts are a restriction... cars can be seperated into street muffled, catless, just past the door seam, ect (not sure about the technicalities but you get the idea).

It may be a boost leak. But once again, I'm going to disagree. A boost leak would benefit torwards NOT blowing a hole in the exhaust. Why would something that decreases HP and pressure within the engine CAUSE something like that? Doesn't add up...

I am only talking about exhaust leak. If there is a loss of power in the car, it is for some other reason and another thread should be made to address it.

That's my story and I'm stickin' to it.

 

[Blitzeclips]

Okay, he said hole, not leak. If there were a leak this would increase turbulence and slow the flow of exhaust however, if there is a HOLE like described then this would serve as the release point of most of the exhaust and being that its in the downpipe it would relieve most of the restriction of the rest of the exhaust. And since turbo cars dont need backpressure this would benefit greatly.

I completely disagree. I mine as well go drill a bigass hole in my downpipe if what you are saying is true. We're not talking about a full out drag car here, it's probably his DD. You do NOT want holes in your exhaust if you have a full cat-back exhaust system. Like i said, it will disrupt the exhaust cycle and probably flucuate idle.

No skillz- I understand what you're saying but No, there really isn't a big difference. Back pressure is needed for any car, turbo or not. To say you dont need back pressure for a turbo car is not correct.
You're preaching away from the topic here. A open header is benefitcial in the way you described, but we aren't talking about headers here. Once again, its his downpipe, and a daily driven car with a cat-back system, NOT A FULL OUT DRAG CAR. Not to mention to extra heat being spewed somewhere under his car and hopefully not on a vital part to keep it running.

Cut-outs should not be mentioned because it was never referred or mentioned in the primary post/thread starter. I see what you're getting at, but If he wanted a cut-out, I'd encourage him to do so, but that's not the case here. It's a hole in a downpipe for a dialy driven car. Cut-outs are effective if they are done properly, not just having a hole blown thru a downpipe where it was never intended. I know what a cut-out is, as we've installed a couple setups on my buddy's z24, and z28.

The con's here outnumber the pro's.... So get that ish fixed!!

 

[fallenauthority]

Get it fixed yes, but is it hurting performance? No. Any escape for exhaust to go through without going through the cat and muffler are better for performance. Im not saying its good to run around with holes in your exhaust cause it will sound retarded and of course is not emissions friendly. If its actually a HOLE, it will help performance, maybe not by a lot but the gasses will flow free-er(?), if its just a tiny hole/leak, it will hurt because then it will cause turbulence in the flow.

 

[Blitzeclips]

Get it fixed yes, but is it hurting performance? No. Any escape for exhaust to go through without going through the cat and muffler are better for performance. Im not saying its good to run around with holes in your exhaust cause it will sound retarded and of course is not emissions friendly. If its actually a HOLE, it will help performance, maybe not by a lot but the gasses will flow free-er(?), if its just a tiny hole/leak, it will hurt because then it will cause turbulence in the flow.

NO!

Just, no...

 

[No_Skillz]

Ok for you NT guys out there who are arguing the the point... a turbo system does NOT need back pressure.

It's funny that the NT guys are arguing about the this to the turbo guys. Not saying that you guys don't know anything about turbo, it's just an observation.

 

[danny_l_2005]

our turbo cars have alot of backpressure in the manifold theres no reason having backpressure after the o2 housing. If it was up to me without neighbors complaining i would be running my exhaust after the o2 housing so i could get a pretty fast spool

 

[Blitzeclips]

o00oOOO0oooooo mann..... Eh, I quit. Later fellas.

 

[blackz2k]

Ok so its generally accepted that less or no backpressure is better for boosted applications. However, a random hole in the downpipe is going to redirect the exhaust flow very abruptly, thus causing a disturbance in this flow, whereas a properly done cutout will redirect the exhaust flow to a shorter, less restricted route. I just don't see where a hole in a downpipe could be useful for performance...

 

[fallenauthority]

Ok so its generally accepted that less or no backpressure is better for boosted applications. However, a random hole in the downpipe is going to redirect the exhaust flow very abruptly, thus causing a disturbance in this flow, whereas a properly done cutout will redirect the exhaust flow to a shorter, less restricted route. I just don't see where a hole in a downpipe could be useful for performance...

Dont get me wrong its certainly not going to be the next thing on the "Free Mods" list. But it certainly wont have some god awful negative affect.

 

[blackz2k]

Dont get me wrong its certainly not going to be the next thing on the "Free Mods" list. But it certainly wont have some god awful negative affect.

Oh well of course not, I would just recommend getting it fixed was all

 

[Kprime911]

i guess its more of a small leak out a small hole from rust rather than a hole perfectly cut out and it makes my exhaust loud. I was also wondering will it affect gas mileage?

thanks

 

[No_Skillz]

i guess its more of a small leak out a small hole from rust rather than a hole perfectly cut out and it makes my exhaust loud. I was also wondering will it affect gas mileage?

thanks

Nope.