This made some serious noise.....
12-22-2007, 08:53 PM
#1
Le Mans Master
Thread Starter
This made some serious noise.....
While at VIR a couple of weeks ago, I was coming out of Oak Tree, and all of a sudden, I heard a pop and the exhaust sounded like it was in the cabin me.
Here is what happened. The top blew out of the X pipe.
I took the exhaust off this afternoon and will get it fixed next week.
Here is what happened. The top blew out of the X pipe.
I took the exhaust off this afternoon and will get it fixed next week.
12-22-2007, 11:57 PM
#3
Team Owner
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CI 3-5-6-7-8 Veteran
Geeze... guess it's a cheap stamped x-pipe part. I blew an air tube off my left header a few years back comming out of turn 5 at VIR... that scared the crap out of me because I thought the motor let go.
12-23-2007, 09:06 AM
#4
Melting Slicks
You ought to get that fixed by getting rid of that junk........The x-pipe is placed to rearward in the system to be REALLY effective. I was seeing the post made by Cass about the shocks.....You'd better work on more than just shocks, buddy.......ST classes are about to get nutty.
12-23-2007, 09:19 AM
#5
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You ought to get that fixed by getting rid of that junk........The x-pipe is placed to rearward in the system to be REALLY effective. I was seeing the post made by Cass about the shocks.....You'd better work on more than just shocks, buddy.......ST classes are about to get nutty.
Very Nutty
12-23-2007, 12:27 PM
#6
Former Vendor
I bet when it went pop. You thought of everything it could be from rear-end to the engine letting go. I had that happen to a turbo manifold, and in 2 senconds,I spent about 2000 bucks in my head.
Randy
Randy
12-23-2007, 08:59 PM
#9
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From the DR Gas Website
Originally Posted by DR GAS
Remember that radio and TV commercial about the piston engine going "Boing-Boing," when it out to go HUMM? Well, all V8 engines with 90 degree cranks, have an out of sync imbalance in their firing order between the right and left cylinder banks. Yes, they do go "Boing-Boing." The firing order imbalance is a necessary sacrifice for dynamic balance of the rotating and reciprocating crank, rods and pistons. Each time the firing order is completed (two full revolutional), two cylinders within each bank will fire and exhaust within 90 degrees of each other. These two cylinders will be exhausting into the header collector or exhaust manifold almost simultaneously. This overlapping condition creates a lot of back pressure and a pop sound. Meanwhile, the opposite exhaust manifold has no activity (or pressure) in it at all. This is where the characteristic, low harsh popping V8 sound comes from.
The most common way of reducing this out of sync imbalance is with rebalancing crossovers such as H pipes and over-and-under X style crossovers. These provide both noise reductions and efficiency (power) improvements. H pipes are effective only at low and mid range. The over-and-under X crossover works a little better but still does not completely rebalance the exhaust at high RPM.
Dr. Gas, Inc. has developed a new generation of crossovers that uses a tangentially siamese junction, in place of the H or over-and-under X. It evenly splits, smoothes, and synchronizes exhaust pressures at all engine speeds. The high and low pressure pulses in the two pipes are evenly imposed on each other, leveling out the pulse time history pressure differences between right and left cylinder banks. Re-synchronizing the exhaust pulses reduces back pressure, cancels sound, and provides additional scavenging. Tests have sound 6 dBa (75%) reduction in sound levels, and increases of 10 to 30 hp, and up to 40 ft-lbs. of torque! Economy, and throttle response are improved. Exhaust flow after the crossover is completely smoothed out. The job the headers started is finished.
One of the most appealing benefits of this system is the modified exhaust note. The deep growling and popping sound is replaced by a higher pitched smooth sound. The exhaust note is similar to a 180 degree header system without the nightmare of tubing.
Dr. Gas crossover kits replace the first 3 to 4 feet of the exhaust system with pre-bent mandrels pieces. Simply measure, cut and weld into place. The system is universal fit for most header applications. After the crossover, any type of dual exhaust, converters, or mufflers may be used with little or no effect on power. Vehicles that have problems meeting sound limits at local area tracks can also benefit with an increase in power tool. And so, the piston engine can go HUMM!
The most common way of reducing this out of sync imbalance is with rebalancing crossovers such as H pipes and over-and-under X style crossovers. These provide both noise reductions and efficiency (power) improvements. H pipes are effective only at low and mid range. The over-and-under X crossover works a little better but still does not completely rebalance the exhaust at high RPM.
Dr. Gas, Inc. has developed a new generation of crossovers that uses a tangentially siamese junction, in place of the H or over-and-under X. It evenly splits, smoothes, and synchronizes exhaust pressures at all engine speeds. The high and low pressure pulses in the two pipes are evenly imposed on each other, leveling out the pulse time history pressure differences between right and left cylinder banks. Re-synchronizing the exhaust pulses reduces back pressure, cancels sound, and provides additional scavenging. Tests have sound 6 dBa (75%) reduction in sound levels, and increases of 10 to 30 hp, and up to 40 ft-lbs. of torque! Economy, and throttle response are improved. Exhaust flow after the crossover is completely smoothed out. The job the headers started is finished.
One of the most appealing benefits of this system is the modified exhaust note. The deep growling and popping sound is replaced by a higher pitched smooth sound. The exhaust note is similar to a 180 degree header system without the nightmare of tubing.
Dr. Gas crossover kits replace the first 3 to 4 feet of the exhaust system with pre-bent mandrels pieces. Simply measure, cut and weld into place. The system is universal fit for most header applications. After the crossover, any type of dual exhaust, converters, or mufflers may be used with little or no effect on power. Vehicles that have problems meeting sound limits at local area tracks can also benefit with an increase in power tool. And so, the piston engine can go HUMM!
12-24-2007, 06:35 PM
#11
Racer
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very informative post sir TAF !
and here is my qestion:
what about a flat plane v8 ?
with all the light weight forged pistons and titanium rods its starting to sound interesting... even doable in a street car
and here is my qestion:
what about a flat plane v8 ?
with all the light weight forged pistons and titanium rods its starting to sound interesting... even doable in a street car
12-25-2007, 03:47 PM
#15
Le Mans Master
Thread Starter
12-27-2007, 09:19 PM
#16
Premium Supporting Vendor
That's ugly. Not a lot of shielding in the floor panel either. Never really thought about getting fragged by my own exhaust before. 
I guess an upside to my wreck last year is that I have a brand new exhaust (without cats - new SCCA T1 rule) on my more or less brand new car.
I guess an upside to my wreck last year is that I have a brand new exhaust (without cats - new SCCA T1 rule) on my more or less brand new car.
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12-27-2007, 09:36 PM
#17
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All of this sounds like a great reason to switch to a rotary. Three moving parts and no imbalance in the exhaust. What a wonderful world we live in, all of these options.
12-27-2007, 09:43 PM
#18
Safety Car
Know any good rotary folks in NorCal? I really want to get my '87 RX7 TurboII out on track this year... even if it will be slower than my mostly stock '06 'vette. :-)
12-27-2007, 11:10 PM
#19
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Jody....you might want to ask Fred about that little hole in your X pipe. Looks a bit fishy to me
Bob
12-27-2007, 11:36 PM
#20
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Eh. Broke the downpipe on my 13BT at Shannonville Motorsports Park one time. Exhaust gets so hot on those cars that it's really hard to keep the downpipe happy.
Know any good rotary folks in NorCal? I really want to get my '87 RX7 TurboII out on track this year... even if it will be slower than my mostly stock '06 'vette. :-)
Know any good rotary folks in NorCal? I really want to get my '87 RX7 TurboII out on track this year... even if it will be slower than my mostly stock '06 'vette. :-)
Are you single turbo? I thought that most twin turbos could beat the corvette on the same size tire. Don't forget, most Mazdas run on 225 or 245's. The Corvette guys I know are all running on 275's and up, mostly up. Granted, my little 13B motor can barely push me around, much less me and some big fat tires. However, if it could I would give them a run for their money. Or at least wreck trying.
