1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Rode in a LOUD 12a last night..

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Old Jan 24, 2002 | 09:00 AM
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Rode in a LOUD 12a last night..

Alright, a friend of mine just installed a new exhaust on his 85 GS. Consisting of, a cleaned up pacesetter header, a huge *** glasspack where the cats usually go, custom straight piped (3.5") to a Cherry bomb(?) muffler. (the thing is a canister about a foot and a half long, 6" in dia, with a 4" outlet)

HOLY CRAP is that thing loud... I thought mine was pretty loud with a leaky exhaust manifild gasket and rapidly dying muffler, but you couldn't even hear it over his AT IDLE! Christ it was loud... I could hear it miles away..
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Old Jan 24, 2002 | 10:03 AM
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sounds like my stage 5 mindtrain setup....but it had a cool deep groul at idle and was load as hell off it
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Old Jan 24, 2002 | 10:22 AM
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Sounds like 'get busted' time to me.
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Old Jan 24, 2002 | 11:20 AM
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Originally posted by MIKE-P-29
Sounds like 'get busted' time to me.
I've been worried about getting busted for my exhast. I have the stock header and a straight pipe, no cats, no presilencer, and straight through muffler(you can actually see through on end to the other). It is LOUD.
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Old Jan 24, 2002 | 02:08 PM
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Wait 'till the mufflers burn out, then it'll be even louder!
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Old Jan 24, 2002 | 06:49 PM
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Re: Rode in a LOUD 12a last night..

Originally posted by rx7gslse
Alright, a friend of mine just installed a new exhaust on his 85 GS... a huge *** glasspack where the cats usually go...
Hehe, the glasspack will be lucky to last a week. If you do a search for "glasspack" here on the board you'll get a lot of results sayiong somthing to the effect of "DON'T do it, it can't handle the heat!"
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Old Jan 24, 2002 | 07:00 PM
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Yeah they said on Mazdatrix that glass packs life can be measured in 'blocks driven' Not much stands up to the hot breathe of a rotary
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Old Jan 24, 2002 | 08:23 PM
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Minutes or Blocks Driven.

Hehe... I can just imagine Mazdatrix's log.

RIP: Shop to the McDonalds

RIP: 5 Minutes on the Dyno

RIP: 2 Minutes on lift checking for leaks

RIP: Shop to gas station

RIP: Exploded on first backfire
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Old Jan 24, 2002 | 08:36 PM
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Got that Glasspack?
Sure, that sound can be felt...
Rotary heat in just one sack,
Melt, melt, melt!
Good-bye Glasspack!

~FuLLsMoKe
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Old Jan 24, 2002 | 09:28 PM
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LOUD

When I put the exhaust on my 83, i wanted to see how loud it realy was. Bolted up the header and took it for a spin. Talk about loud enough to FEEL. At 7000 RPM it would make the fillings in you teeth shake. Boy that was fun.

Tried the glass pack deal to. It lasted about a week. Pulled it off, cut it in half and sure enough it was empty. I stuffed it full of stainless steel wool and welded it back together and it has been on the car for about a year now and works great.
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Old Jan 24, 2002 | 10:40 PM
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About 2 weeks ago I took my rx-3 out and it had jsut a header on it for a drive. (still stock 12a). I was wearing ear mufs and they were shaking on my head. Then about 4k it would set up a harmonic that you could feel in your chest then at 7.2k it sounded like a jet. Any ways I only got about 3 miles then the carpet started to get hot from where the header was flowing under the floor board. I got home and it had just started to melt so i am glad I did not drive it any more or I would have had a fire. I will say though that the 12a's are a lot louder than 13b's. I think because they are higher pitch. I have a street ported 13b in my truck and that was nothing compared to the 12a off the header.

CJG
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Old Jan 24, 2002 | 10:55 PM
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Not to self: Route pipe out from side of car if running open header.
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Old Jan 25, 2002 | 12:05 AM
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Re: LOUD

Originally posted by toyman
When I put the exhaust on my 83, i wanted to see how loud it realy was. Bolted up the header and took it for a spin. Talk about loud enough to FEEL. At 7000 RPM it would make the fillings in you teeth shake. Boy that was fun.

Tried the glass pack deal to. It lasted about a week. Pulled it off, cut it in half and sure enough it was empty. I stuffed it full of stainless steel wool and welded it back together and it has been on the car for about a year now and works great.
Toyman, did it really work? I have been considering re- stuffing this glasspack my friend is willing to give me with stainless steel. Does it actully muffle anything?
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Old Jan 25, 2002 | 12:12 AM
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Originally posted by Rotortuner
About 2 weeks ago I took my rx-3 out and it had jsut a header on it for a drive. (still stock 12a). I was wearing ear mufs and they were shaking on my head. Then about 4k it would set up a harmonic that you could feel in your chest then at 7.2k it sounded like a jet. Any ways I only got about 3 miles then the carpet started to get hot from where the header was flowing under the floor board. I got home and it had just started to melt so i am glad I did not drive it any more or I would have had a fire. I will say though that the 12a's are a lot louder than 13b's. I think because they are higher pitch. I have a street ported 13b in my truck and that was nothing compared to the 12a off the header.

CJG
That's why I routed my dump pipe down and towards the side of the car! Plus I only run it for a minute or two at a time with the dump cap off.



- PJ (Loud and Proud!)
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Old Jan 25, 2002 | 05:16 PM
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Re: LOUD

Originally posted by toyman
When I put the exhaust on my 83, i wanted to see how loud it realy was. Bolted up the header and took it for a spin. Talk about loud enough to FEEL. At 7000 RPM it would make the fillings in you teeth shake. Boy that was fun.

Tried the glass pack deal to. It lasted about a week. Pulled it off, cut it in half and sure enough it was empty. I stuffed it full of stainless steel wool and welded it back together and it has been on the car for about a year now and works great.
That's pretty much how a pre-silencer works. A glasspack with steel wool instead of fibreglass.
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Old Jan 25, 2002 | 06:44 PM
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Hey Peejay, just wondering how did you set up your dump? Do you have control over it from inside the car or do you have to jack it and change it? Thanks. -George
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Old Jan 26, 2002 | 12:08 AM
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Started up YaYa with just the header. It could be felt blocks away. Put the road race midsection with the presilencers on and it could be heard miles away at full throttle. I did not get to put the borla muffler on as the thing blew up before I got to the muffler shop.


I got two cars with bad rear compression


And I just ran out of 12a's.....DAMN

Anybody got a really cheap one?
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Old Jan 26, 2002 | 12:16 AM
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Originally posted by NanaimoRx-7
Hey Peejay, just wondering how did you set up your dump? Do you have control over it from inside the car or do you have to jack it and change it? Thanks. -George
I had a setup where i could contol it fron the dash, but it didn't seal right and ended up sounding to loud all of the time. It was a crappy one from jc whitney though. Supposedly the ones from www.exhaustcutouts.com will seal correctly
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Old Jan 26, 2002 | 01:26 AM
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No jack, no in-car switch. Just drive it to the track, lay down in to grass, pull off three wingnuts (Race Readies gives you a neat little tool that gives you plenty of leverage on 'em) and take the cap off. Race around, when the track closes pop it back on and drive home.

One thing though... the car runs a lot leaner with the cap off. The fuel pump I had was internally regulated to about 5-6psi, and what I found gave the best results was running 3-3.5psi through the exhaust (Holley regulator), and when I'd run with the cap off, I'd bypass the regulator entirely. I also eliminated the return line with this setup for max fuel flow - I was running lean at the top end until I capped off the return line. A bigger fuelpump than my part-store $30 special would have solved that problem. If I'd spent the $68 on the Holley pump in the first place, it would have come with the $25 regulator, so I would have only spent $13 more by getting the Holley instead of my rig-job.

Yes I know I could have just rejetted the carb... but jets cost something like $10-15 a pair, and how many do you need to buy to dial it in? I'm too cheap for that, the car wasn't worth it
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Old Jan 26, 2002 | 09:57 AM
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back in high school, i blew out a fist sized hole in the side of my old '79s thermal reactor. i had to drive it for a week like that! OMFG! it was hellaciously loud at idle.... give it gas and BRAAAAAAAAAAP! it sounded like the hell's angels were having chainsaw fights in my engine compartment after eating taco bell!
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