I have a leak in the flex section of my y-pipe (its the old Jet-Hot kind, so I new it would happen...I've already ordered a Cattman SS one...).

How will this effect performance? The power in the car does not quite feel as even as it normally does...and that little dip in torque that 4th gens have seems to be more noticable.

I am going to the track tonight...will this leak hurt my times?

Also, the leak buzzes when I start the car..really bad! But after driving for 5 minutes, when the exhaust heats up, it gets much, much quiter. Don't know if that makes a difference.

 

Your low end will be hurt. I have a small leak myself on the back end of my muffler. There is a little bit of lag or hesitation when I take off somtimes. I'm having my muffler shop fix the weld next week. Why not just have the flex section repaired instead of spending all that money on a new Y-pipe.

 

Well, I've been wanting a Stainless Y-pipe for a while now. The wonderful Rochester/Buffalo winters are killing the steel exhaust that is down there now.

 

Water and salt do tend to have a taste for metal. If I were you, I would not do the track thing untill the new Y-pipe is installed. Unless you want to see the difference in times between a leaky Y-pipe and a non leaky Y-pipe. You could have a muffler shop fix it before you race. It shouldn't cost you no more than about $50 to fix.

 

Why wouldn't you race? Yeah, my times won't be as good, but there isn't really any harm to be done, right?

 

My Jet-Hot Cattman flex section leaked also. I think it hurt the low end but it mostly made horrible noises. But instead of ordering a new Y, I just had a good shop cut and weld in a new QUALITY flex section(ie.. lined). It helped reduce the noise SIGNIFICANTLY.

 

is the leak the 'hissing' sound that you hear from the exhaust above 3000 rpm when you get on the throttle hard?

if not, what is the hissing sound? not that I don't like it, i think it actually sounds good...

-V

 

as the wise trailer trash hick said...it fixes everything....

and try to keep some ventilation...dont die from carbon monoxide poisning

 

Uh, duct tape would melt(I'm only saying this because I didn't see the smilie at the end of the comment).

 

Ha ha, someone actcually suggested that I use duct tape last night at the track. I thought he was kidding, but now I'm not so sure.

Well, I did run at the track last night, and my times sucked, I feel mainly in part to the exhaust leak. I couldn't get a 60' time less than 2.3. Overall my times where about .3s slower than my previous times.

Guess that answers my questions about performance

 

An exhaust leak won't affect performance that much. The reason you are seeing a .3 slower et is because of the heat. In March and April I was running 14.7/14.8@94 and now I'm running 14.9/15.1@92. The difference is the weather. My best ets were in 50 degree dry weather and now it's 80+ degree humid weather. Heat and humidity suck a ton of life out of the motor. Take a look at your timeslips. I can almost assure you that a majority of your et is lost in the first 1/8th. In hot weather, my car is .3 slower to the 660' vs cooler weather. Your 60 foots are slow because you aren't making as much torque.

Also, you describe a rattley noise on startup. That's not your y-pipe. That's the RT cat. Nearly every RT cat (including mine) has this problem. The bricks become loose in the housing. Once the bricks expand on warmup, the rattle goes away.


Dave

 

I know the RT cat rattle that you're talking about (I have it too), and this is not it. Its more of a buzzing...that and I've gotten under the car and felt the exhaust leaking from the y-pipe

As far as times...I don't think the weather made the entire difference. At the end of the night, it was only around 60-65 out. It wasn't really that warm. I think if the exhaust was in better shape, I think I could have run high 14.8's.

Like I said in my other post, I figure I was running mid to high 14.9's most of the night, but I was backing off at the line to make sure I didn't break out. That and I only dialed a 14.99 because in my first two runs my best was a 15 flat.

 

It depends on how big the leak is. A pinhole leak won't affect it all that much but if it's larger than a few millimeters it'll disrupt the flow. The key to a good exhaust is the least amount of turbulence to keep the exhaust gas velocity high. An exhaust leak will cause the flow to become turbulent since the exhaust gas will want to flow out of the hole and not the rest of the piping (bad for low end flow). You can wrap it with exhaust piping tape which should withstand the higher temps better than duct tape.

 

Turbulence is a good word for my exhaust flow now. Acceleration and power feel a lot less even, and a lot less smooth then normally.

Thanks.

 

i had a cracked y pipe..and this is what happend
1. Lost pressure always had the pedal to the floor
2. NO hp..i think i was at bout 170hp
3. There was an annoying sound similar to a snoring person
4. got left by winnebagos!!
5. Had exhaust fumes everwhere (i.e. inside the car)
6. Couldnt get a date

But thats me. I had a cracked stock pipe.. I upgraded to a Cattman y-pipe cause nissan wanted 7 bills for a new stock one...

 

why does sound sooo familiar? i found out the same thing when i was installing my exhaust... damn nissan... oh well, better for less, why not!?

 

oh i guess nissan must just wanna jerk cats..