Exhaust "crackling" from 2500-3000RPM

Greystang302 · 05-07-2001, 10:42 PM

My current mods can be found in the signature. I never noticed this crackling sound while I had my tailpipes hooked up, but I removed them the other day for the hell of it. With the tailpipes removed, if I am giving it any gas AT ALL, it makes a nasty crackly/rattling sound through the exhaust. I am putting the tailpipes back on tomorrow, to see if it is still there and I just never noticed it. The car is tuned well, with no detonation present. I am currently at 42 psi of fuel pressure, and 20^BTDC timing on 93 octane. The TW heads like this much timing, I am not insane.

Oh, my Accel 300+ ignition is also off the car right now, it is about to get sent back to Mr. Gasket because it quit working again.

BTW, my CVX mufflers are a straight-through design with perforations around the inside of the pipe, and packing inside the muffler... if you aren't familiar with them.

Is this just the typical X-pipe sound? I can't help but wonder if it's normal to have this sound when running dumps? I will let ya know what I find out when I install the tailpipes again tomorrow.

------------------
1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/245/50ZR16 SZ50s, Factory Five upper and lower rear control arms, SVO pulleys, Accel 300+ and Race Wires, K&N conical, '93 Cobra valance, Auto Meter, 130G<A HREF="ht

[This message has been edited by Greystang302 (edited 05-07-2001).]

FroMack · 05-08-2001, 12:45 AM

Maybe you have a leak in your exhaust system.
My buddy had a leak in his header gasket and his exhaust was alway crackling.

Greystang302 · 05-08-2001, 02:50 PM

Thanks for the idea, but the crackle is coming from inside the exhaust system... I know what exhaust leaks sound like, and this is something different. I installed the tailpipes this morning, and the sound is still present, but it is subdued now. I guess that big turn over the axles tones the sound down some, not to mention the added length of pipe. I guess that's why I never noticed it before.

------------------
1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

13sec95vert · 05-08-2001, 04:07 PM

this crackling sound can be from not enough backpressure which was created when you took off the tailpipes

------------------
1995 gt convertible:
3.55 gears, underdrive pulleys, cobra intake , fenderwell cold air, 65mm throttle body, 75mm mass air meter, off-road h pipe, borla cat back, custom diablo chip, 155lph fuel pump lentech aode street terminator w/ 10" converter stalls at 2800 rpms, yokohama a520(drag radials) 275s

Greystang302 · 05-09-2001, 08:16 AM

That does make sense... the tailpipes would provide a little bit more backpressure in the system with their big turn over the axles.

------------------
1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

LX XLR8R · 05-09-2001, 12:34 PM

hey i just blew my second accel 300+ also.....whats the deal with these..i need to send mine back also..i wonder how many of thses things are bad..its so easy to hook up a blind retard would have no problems..they tried to tell me i have a bad ground..no way in he11..i well ill keep sending them back till i get one that lasts longer than 3 weeks

------------------
1987 black notch(ex 4 banger)
DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one..
AIM=onesillynotch

Demon69 · 05-09-2001, 08:28 PM

Exhaust systems always crackle when a pipe is taken off, either the pipe from the muffler back, or taking the muffler directly off. This is a normal sound when anything from the exhaust is taken off. I suggest you replace the pipe soon, though. Running a shorter than stock exhaust will cause numerous problems within your lower block.

Greystang302 · 05-10-2001, 12:26 PM

What kinds of problems could possibly be caused within the short block, by running a shorter exhaust system? People run open headers at the track all the time, tons of people run mufflers with dumps on them and no tailpipes. Please explain.

I'm not sure what the deal is with the Accel 300+ ignition... If they would let me, I would trade the damn thing in on an MSD 6AL!!! I hope they replace it for me again for free though.

------------------
1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

05-11-2001, 02:57 AM

I've heard that if you run open headers or manifolds what happens is the heating and rapid cooling within the exhaust actually causes temperature waves that will cause the exhaust valves to crack and start leaking (if you've ever heard the term "burnt" exhaust valves that's what this is), and when you shut off the vehicle cool air is rapidly sucked in and cools off the valves too quickly, which is why some people stuff rags in open headers when they shut them off. Open headers shed heat alot faster than tailpipes do and if you shut off the engine with full exhaust it's likely to suck back in exhaust instead of cool air. you should be safe running an X-pipe and mufflers. I also agree with Demon 69. There's a Volkwagen Scirocco around my neighbor hood that has the same loud crackle from the lack of exhaust it has and i can hear it in my exhaust even though it's full exhaust, you're just more prone to hear it because your exhaust has such little restriction and is probably loud anyway.

05-07-2001, 10:42 PM	#1
Greystang302 Registered Member Join Date: Oct 1999 Location: Round Hill, VA Posts: 339	Exhaust "crackling" from 2500-3000RPM My current mods can be found in the signature. I never noticed this crackling sound while I had my tailpipes hooked up, but I removed them the other day for the hell of it. With the tailpipes removed, if I am giving it any gas AT ALL, it makes a nasty crackly/rattling sound through the exhaust. I am putting the tailpipes back on tomorrow, to see if it is still there and I just never noticed it. The car is tuned well, with no detonation present. I am currently at 42 psi of fuel pressure, and 20^BTDC timing on 93 octane. The TW heads like this much timing, I am not insane. Oh, my Accel 300+ ignition is also off the car right now, it is about to get sent back to Mr. Gasket because it quit working again. BTW, my CVX mufflers are a straight-through design with perforations around the inside of the pipe, and packing inside the muffler... if you aren't familiar with them. Is this just the typical X-pipe sound? I can't help but wonder if it's normal to have this sound when running dumps? I will let ya know what I find out when I install the tailpipes again tomorrow. ------------------ 1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/245/50ZR16 SZ50s, Factory Five upper and lower rear control arms, SVO pulleys, Accel 300+ and Race Wires, K&N conical, '93 Cobra valance, Auto Meter, 130G<A HREF="ht [This message has been edited by Greystang302 (edited 05-07-2001).]

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05-08-2001, 12:45 AM	#2
FroMack Registered Member Join Date: Mar 2001 Posts: 24	Maybe you have a leak in your exhaust system. My buddy had a leak in his header gasket and his exhaust was alway crackling.

05-08-2001, 02:50 PM	#3
Greystang302 Registered Member Join Date: Oct 1999 Location: Round Hill, VA Posts: 339	Thanks for the idea, but the crackle is coming from inside the exhaust system... I know what exhaust leaks sound like, and this is something different. I installed the tailpipes this morning, and the sound is still present, but it is subdued now. I guess that big turn over the axles tones the sound down some, not to mention the added length of pipe. I guess that's why I never noticed it before. ------------------ 1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

05-08-2001, 04:07 PM	#4
13sec95vert Registered Member Join Date: Dec 2000 Location: Katy Texas Posts: 70	this crackling sound can be from not enough backpressure which was created when you took off the tailpipes ------------------ 1995 gt convertible: 3.55 gears, underdrive pulleys, cobra intake , fenderwell cold air, 65mm throttle body, 75mm mass air meter, off-road h pipe, borla cat back, custom diablo chip, 155lph fuel pump lentech aode street terminator w/ 10" converter stalls at 2800 rpms, yokohama a520(drag radials) 275s

05-09-2001, 08:16 AM	#5
Greystang302 Registered Member Join Date: Oct 1999 Location: Round Hill, VA Posts: 339	That does make sense... the tailpipes would provide a little bit more backpressure in the system with their big turn over the axles. ------------------ 1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

05-09-2001, 12:34 PM	#6
LX XLR8R Dirk Diggler Join Date: Feb 1999 Location: SLOATSBURG, NY Posts: 1,931	hey i just blew my second accel 300+ also.....whats the deal with these..i need to send mine back also..i wonder how many of thses things are bad..its so easy to hook up a blind retard would have no problems..they tried to tell me i have a bad ground..no way in he11..i well ill keep sending them back till i get one that lasts longer than 3 weeks ------------------ 1987 black notch(ex 4 banger) DSS 306 w/ main support...Elderbrock 6028 heads..gt-40 intake..24# injectors...70 mm tb..77 pro-m...accel 300+..mac full legnth..tremec w/ pro5oh...full MAC exhaust,off road h-pipe,long tubes, catback...ron davis radiator..subframes, control arms...CFDF II..o yea holley FPR sucks..dont buy one.. AIM=onesillynotch

05-09-2001, 08:28 PM	#7
Demon69 Registered Member Join Date: May 2001 Posts: 2	Exhaust systems always crackle when a pipe is taken off, either the pipe from the muffler back, or taking the muffler directly off. This is a normal sound when anything from the exhaust is taken off. I suggest you replace the pipe soon, though. Running a shorter than stock exhaust will cause numerous problems within your lower block.

05-10-2001, 12:26 PM	#8
Greystang302 Registered Member Join Date: Oct 1999 Location: Round Hill, VA Posts: 339	What kinds of problems could possibly be caused within the short block, by running a shorter exhaust system? People run open headers at the track all the time, tons of people run mufflers with dumps on them and no tailpipes. Please explain. I'm not sure what the deal is with the Accel 300+ ignition... If they would let me, I would trade the damn thing in on an MSD 6AL!!! I hope they replace it for me again for free though. ------------------ 1989 Mustang GT, Charcoal Gray w/Titanium, 80k miles -- Stage III TW heads, E-cam, ported Cobra intake, Compucar N2O, 65mm TB, Kirban FPR @ 42psi, C&L 76mm MAF w/30#'ers, BBK 1 5/8" Jet-Hot long tubes, Dr. Gas X-pipe, Dynomax CVX cat-back, 3.55 gears, Tremec 3550 w/Hurst Comp. Plus, Steeda quadrant, Zoom HD clutch, 16"x8.5" OZ Monte Carlos w/Nitto DRs, Factory Five control arms, SVO pulleys, Accel 300+, K&N, '93 Cobra valance, Auto Meter, 130G<A HREF="http://race.aplus.net/" TARGE

05-11-2001, 02:57 AM	#9
84stangLX Guest Posts: n/a	I've heard that if you run open headers or manifolds what happens is the heating and rapid cooling within the exhaust actually causes temperature waves that will cause the exhaust valves to crack and start leaking (if you've ever heard the term "burnt" exhaust valves that's what this is), and when you shut off the vehicle cool air is rapidly sucked in and cools off the valves too quickly, which is why some people stuff rags in open headers when they shut them off. Open headers shed heat alot faster than tailpipes do and if you shut off the engine with full exhaust it's likely to suck back in exhaust instead of cool air. you should be safe running an X-pipe and mufflers. I also agree with Demon 69. There's a Volkwagen Scirocco around my neighbor hood that has the same loud crackle from the lack of exhaust it has and i can hear it in my exhaust even though it's full exhaust, you're just more prone to hear it because your exhaust has such little restriction and is probably loud anyway.