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

Turbo Troubles........How Hot is Too Hot ?

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Old Mar 15, 2003 | 04:46 PM
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Unhappy Turbo Troubles........How Hot is Too Hot ?

Recently purchased an 82 'Kit' that was built by a local Rotaray hero. Honestly he owned and operated a local RX-7 shop for 30 years until his recent retirement.

The car is a hybrid of a 1982 chasis with a new 13B four port engine. He told me that he purchased the engine new directly from Mazda for his showroom. Also from his showroom was the wide body kit, a RAJAY turbo, a Holly 600CFM carb, centerforce clutch, and performance exhaust system. The motor is reported to have only 20,000 miles on it now.

After sitting up in a barn for ten years I bought it for a project. Yesterday I finally got it cranked. It sounds really good. Two points of concern that I have is the fact that it has no intercooler and - here's the main concern - after allowing it to run for about 7 - 8 minutes, the exhaust manifold began to G L O W red hot ..... I have no way to know how hot it actually gets. What is normal ? Doesn't this seem to be excessive heat generation ?

Any sugestions would be appreciated....

Jeff

Last edited by Hootster; Mar 15, 2003 at 04:49 PM.
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Old Mar 15, 2003 | 05:51 PM
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From: chatsworth,Ca.
how high was the car idling? 3-4k rpm's constant will cause a lean mixture becaust of no load,not driving, .. driving the car will put the carb into the main circut allowing it to keep the proper mixture instead of transitioning on and off if its set at such a high idle
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Old Mar 15, 2003 | 05:53 PM
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From: chatsworth,Ca.
also make sure your timing is set correctly as that could cause extremly high exh. temps also
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Old Mar 15, 2003 | 06:36 PM
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Good advise, but I also just want to add that my header was glowing red hot when my trailing ignition wasnt working once. Maybe check spark, and get some new plugs .

~T.J.
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Old Mar 15, 2003 | 08:39 PM
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I thought glowing exhaust indicated a rich condition.... Maybe I'm wrong.

Conway
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Old Mar 15, 2003 | 08:52 PM
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I have no way to know how hot it actually gets.
They make infra-red thermometers that are good for this kind of stuff. Some guys use em to measure their CPU operating temp, I think it'd be handy for exhaust manifolds and stuff =P

Point, shoot, look at the little screen. Doesn't get simpler

(not worth buying for this one situation, though, check your timing/plugs)
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Old Mar 16, 2003 | 12:21 AM
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Originally posted by Conway
I thought glowing exhaust indicated a rich condition.... Maybe I'm wrong.

Conway
Lean makes more heat, weird eh?

~T.J.
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Old Mar 16, 2003 | 09:59 AM
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Yeah, I know leaner means hotter, but glowing headers/exhaust indicates a rich condition where unburned fuel burns in the exhaust. Here are the threads to proove it:

https://www.rx7club.com/forum/showth...hlight=glowing

And RacerMike's comments in:

https://www.rx7club.com/forum/showth...hlight=glowing


Right?

Conway
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Old Mar 16, 2003 | 11:49 AM
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From: lol
what part of tejas you in?



And what shop did this retired guy own?


Did you rebuild the carb?

Redo the entire fuel system, and then get an air/fuel ratio gauge, and start tuning.... also, if its a blow through, get a intercooler, if its a draw thru, cant use it....

Well, tell us what you have done to it since you have gotten it...........


and get some damn pics

Laterz, Andrew
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Old Mar 16, 2003 | 07:08 PM
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Originally posted by RotorMotorDriver
Lean makes more heat, weird eh?

~T.J.
Nope not at all, makes perfect sense

Ever see a cutting torch? i cant spell the gas name for some reason LOL its abbrev. is AXY , but it wont cut didly ****, until you throw oxygen to it, and then it will cut anything almost
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Old Mar 16, 2003 | 07:21 PM
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Originally posted by MIKE-P-28
Nope not at all, makes perfect sense

Ever see a cutting torch? i cant spell the gas name for some reason LOL its abbrev. is AXY , but it wont cut didly ****, until you throw oxygen to it, and then it will cut anything almost
Axytelene

EDIT: Acetylene

Can't use one for crap... I ended up destroying an exhaust flange on my old honda instead of melting out the studs... Now I've gotta figure out how to put regular bolts through some fucked up lookin holes...

Oh well, didn't make a 10 foot fireball when I lit it... I should be happy.

Last edited by Pele; Mar 16, 2003 at 07:33 PM.
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