Exhaust tip size for stock pipe

Exhaust tip size for stock pipe

Postby miniVan [OP] » March 1st 2015, 9:52pm

I've been considering to put on an exhaust tip on the stock exhaust pipe I have on the 97 Safari. I was wondering what size tip would work on the stock pipe, would an inlet size (clamp on size) of 2.5" with an outlet size (diameter) of 3" work?
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Re: Exhaust tip size for stock pipe

Postby WoodButcher » March 1st 2015, 11:46pm

Should...
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Re: Exhaust tip size for stock pipe

Postby miniVan [OP] » March 1st 2015, 11:59pm

Thanks. What should the maximum length of the pipe be? If I were to go with a longer tip like 8" or 12", does the tip only bolt onto the very end of my stock pipe, or can I "push it in" or overlap the tip with the stock pipe so it doesn't stick out so much at the end?
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Re: Exhaust tip size for stock pipe

Postby WoodButcher » March 2nd 2015, 12:11am

Look at your van, there should be a straight section on the end that brings it out past the fender. I really can't say because your van is at least 10 years old at the minimum so the possibility that the exhaust is not the original is pretty fair.
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Re: Exhaust tip size for stock pipe

Postby Lumpy » March 2nd 2015, 12:42am

Here's the formula -

First figure the area(s) of the smaller and larger exhaust pipe sections [2pi x r]

2 x 3.14 x 2.5 = 15.70 inch [smaller pipe area]]
2 x 3.14 x 3.0 = 18.84 inch [larger pipe area]

Convert both measurements to beard seconds.
[Substitute angstroms x 100 if more convenient]

[Smaller] 15.7 = 79,756,000 b.s.
[Larger] 18.84 = 95,707,200 b.s.


600 [Idle RPM] x 95,707,200 [large area]
--------------------------------------------------- / 4300 [cc eng displacement] = .17
79,756,000 [small area]

The answer (0.17) is the index of HP increase (17% rounded) expected when increasing resonator diameter over stock.

Above assumes you have NGK spark plugs, do NOT have exhaust header wrap and have charged your primary battery for at least an hour.

Figures are not accurate if you have either red or blue body effect lights due to the doppler shift created by the red or blue spectrum saturation.


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Re: Exhaust tip size for stock pipe

Postby jaywoo65 » March 2nd 2015, 12:48am

Maybe something like this.
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Re: Exhaust tip size for stock pipe

Postby chevymaher » March 2nd 2015, 1:33am

jaywoo65 wrote:Maybe something like this.

Believe it or not I almost posted that.
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Re: Exhaust tip size for stock pipe

Postby miniVan [OP] » March 13th 2015, 5:23am

So I've been trying to install the bolt on exhaust tip I bought a while back, but it seems to move along on top of my stock exhaust pipe even when I hand tightened it with my locking pliers. The spec of the tip sais the inlet is for 2.75" to 2.5" diameter pipes, and it seems that the exhaust pipe of my 97 is around 2.5" in diameter. Also, on the tip I received, it said to tighten the clamp bolt on the tip by "torquing it to 40lb-ft". I've tried hand tightening the tip's clamp bolt with my locking hand held pliers to the max I can, but the exhaust tip still had a tendency to slide and wiggle on my stock exhaust pipe. Am I supposed to use a special wrench for the bolt on the clamp when it refers to torquing it to 40lb-ft in the instructions?
I was considering to probably pay a shop to weld it for me if I can't get it clamped on myself.
Anyways, do you guys think using a torque wrench at 40lb-ft would tighten the bolt on the clamp even more than I am capable with using locking pliers, since it seems like it can't tighten the bolt anymore if I only use arm strength with locking pliers. Would the bolt be able to rotate some more if I tried using a torque wrench.?..I haven't tried it yet
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Re: Exhaust tip size for stock pipe

Postby Lumpy » March 13th 2015, 6:56am

You probably need to tighten it with something more substantial. Have you got sockets and a ratchet or breaker bar? How about a box end wrench? 40 ft/lbs means you're putting the equivalnt of 40 lbs force on the wrench at 1 ft away from the bolt. Probably pretty hard to do with any kind of pliers. Don't use a torque wrench to "muscle" the thing. That's only for checking final torque or tightness. Actual torque here isn't critical, only that you get it tight enough to stay on.

If the inlet of the new tip is indeed 2.75 and your tail pipe is 2.5, that's a lot of crush to make happen. Crushing a steel cylinder to 1/4 inch smaller diameter means that steel has to go somewhere. The hydraulic expander/compressor machines that muffler shops use exert several TONS of pressure on the pipe to literally stretch or compress the steel. Pretty difficult to do with any kind of hand tool. Having it welded on would be the best solution. It's not expensive if you find a small mom and pop shop. Midas and similar will cost a lot or might not want to do it at all.

The redneck engineering way, not my first choice, would be to cut some slits lengthwise into the pipe inlet. THEN tighten your clamp thing. It'll leak exhaust but that might not be a concern at the distal end of the exhaust, except to the smog station if you have that where you are. Cleaner function and looks would be a weld.


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Re: Exhaust tip size for stock pipe

Postby Silverhawk » March 14th 2015, 6:14pm

Do yourself a favor and throw the tip away! They are a much thinner mete land will rust away in less than a year. Welding it on would only result in having to cut it off latter. If you try to torque the bolts tight, the threaded holes will strip out! If you insist on putting it on, use a short sleeve pipe of in between size as a spacer. This will give more surface compression to the tailpipe than just the bolt tips.
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Re: Exhaust tip size for stock pipe

Postby Silverhawk » March 14th 2015, 6:30pm

If you want to dress up your exhaust, you can simply spray it with BBQ Black Heat Temp Paint like I do!
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Re: Exhaust tip size for stock pipe

Postby Silverhawk » March 18th 2015, 7:06pm

If you feel you must use it just because you have it, cut down both sides of the inner end and use a real muffler clamp on it!
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