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

SE falls flat

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Old Aug 9, 2012 | 05:31 PM
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From: Sandy Eggo
SE falls flat

soo my GSL-SE is falling flat on its face above 3k and at WOT it has a scream like whistle i have no idea what could be wrong just replaced the wires, plugs, coils, cap, and rotor, and its not my clutch either i have no idea what to do. it has a rough idle at times dependent on tps/idle screw adjustment

thanks in advance for any help
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Old Aug 9, 2012 | 06:28 PM
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From: La Habra
do you have a stock exhaust?
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Old Aug 9, 2012 | 06:46 PM
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Not your clutch as in your fan clutch or trans. clutch? How about air filter...is the lid on properly and tight? Air intake open? Just some more suggestions...
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Old Aug 9, 2012 | 07:03 PM
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From: https://www2.mazda.com/en/100th/
if it makes whistling noises, i think i'd look at the exhaust. could be a plugged cat, or a collapsed muffler.

step 2 would be to make sure the #2 throttle valves actually open, there is a thermovalve that keeps them shut before the car warms up, and it fails. i would verify it opens, and if the valve is bad i usually bypass it, as its not cheap. its #2 because it takes 5 minutes to check.

step 3 would be to check fuel pressure. i had one car that had the aftermarket fuel filter rust itself shut. car would be fast and then gradually loose power, so it was fine getting on the freeway, but getting off it could barely make it over the overpass!
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Old Aug 9, 2012 | 07:07 PM
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From: La Habra
the whistling and no power sound like symptoms of a clogged exhaust(cat if you have one). easiest way to test is with a vacuum gauge hooked up and snap the throttle, the gauge should fall below its idle vacuum for a moment when the throttle shuts then go back to normal. if it slowly returns to its idle vacuum and doesn't drop below for a second then you've got a restriction
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Old Aug 9, 2012 | 11:24 PM
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From: Sandy Eggo
Ya the exhaust is stock and that's what i was thinking with the cat clogged or the muffler collapsing it sounds like its coming from the transmission tunnel but the transmission shifts fine and fuel filter is brand new stock replacement ill check the Thermovalve can you tell me where it is
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Old Aug 10, 2012 | 12:54 AM
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From: La Habra
its on the passenger side behind the intake tube at the dynamic chamber on the back. the water thermo valve works by supplying vacuum to the diaphragm to control the plates behind the secondary throttle plates when the engine is cold(vacuum pressent=plates closed). but even when cold, when you rev up the engine, the vacuum is non existant anyway so the plates open. when the engine is hot, the plates are open all the time(because the valve is vented to atmosphere). So even if it got stuck closed, when you rev up the engine, there is no vacuum at the diaphragm and the plates open. only vacuum closes the plates behind the secondaries(but only when cold)! unless the linkage is physically stuck, then the plates wont open but this is hardly ever the case. i would just check the exhaust for a restriction.

Last edited by xXGslseSleeperXx; Aug 10, 2012 at 12:59 AM.
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Old Aug 17, 2012 | 02:13 AM
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From: Sandy Eggo
Sooo put on my racing beat header and presilencer today and holy crap its awesome ya my cats sounded like marracas so that was the problem

thanks for the help

but now its really loud and kinda sounds like crap any recommendations on good mufflers that will quiet it down
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Old Aug 17, 2012 | 05:34 AM
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From: La Habra
Hahaha, ya i run a streetable with no presilencer ant 2 1/4" over axle with magnaflow strait thru at the very end. With auxiliaries open it hurts. Before i ran 2 magnaflows inline and they worked pretty good a deepening the tone and muffling but after alot of track use they burned out and the high pitchedness came back. For the money i couldn't be more satisfied but if you want one youll never replace id go back to racingbeat. Also before i ran the strait thru magnaflows i used a crossflow at the very end and that worked very well at muffling with no feel of loss in power or collapsing under heat.
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Old Aug 17, 2012 | 01:55 PM
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From: Sandy Eggo
what about a spintech think it will hold up?
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Old Aug 17, 2012 | 02:04 PM
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From: https://www2.mazda.com/en/100th/
Originally Posted by SDsa22c
what about a spintech think it will hold up?
just from looking at some pictures, probably not. the rotary's ports open much faster, and the gasses exiting the engine are supersonic, so the rotary is hard on mufflers. it will last for a while, but eventually the baffle/spinny things will break.
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Old Aug 18, 2012 | 10:51 AM
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Originally Posted by SDsa22c
Sooo put on my racing beat header and presilencer today and holy crap its awesome ya my cats sounded like marracas so that was the problem

thanks for the help

but now its really loud and kinda sounds like crap any recommendations on good mufflers that will quiet it down
My old 84 ran the full racing beat system, muffler inclusive, and it sounded great.

The present 83 GSL is running a Monza exhaust system that you can get off http://www.blackdragonauto.com/ - it's fairly docile sounding below 3K.

Since you're running RacingBeat, I'd say stick with the RacingBeat muffler. The power pulse mufflers are nice (RX7 1975-1985: Exhaust - Cat-Back Systems: Power Pulse RX-7 Muffler - 83-85 RX-7 - should fit your GSL-SE)

Of course, I haven't really heard a RX7 1975-1985: Exhaust - Universal Parts: Rotor Muffler - REV25 - on a 12A/13B, so I dunno.

On the Furai it does sound awful good. But that's 3 rotors.

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Old Aug 18, 2012 | 03:12 PM
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From: Sandy Eggo
ya but that kinda out of my price range i have like a 190 bucks

and i dont think SDPD is gonna like my car so i really cant wait off on building something, i can weld so i just want to know what muffler will hold up to the heat

Last edited by SDsa22c; Aug 18, 2012 at 03:18 PM.
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