davidarmy

my downpipe getting red hot. I know it is not the cat, because I switched it with a midpipe for test purpose. No check engine lite.

dgeesaman

iTrader: (7)

is it the stock downpipe?

If so, change it out now for a straight-through aftermarket.

TwinTurbo93

I've seen my DP getting red hot at night after a hard summer drive, that's common.

davidarmy

yes I have an aftermarket downpipe. it gets hot almost right away.

aw101584

I agree, mine gets red after a long hard run...

911GT2

I've never seen mine get red, and I have the rest of the exhaust completely stock. The downpipe is aftermarket, but the cat and cat-back are stock.

For those that have glowing dps, are your temp gauges reading unusually high? Do any of you have a way of monitoring intake temps (just to see if ambient engine bay temps are significantly higher than those of us without glowing pipes.)?

clayne

After a hard run I definitely see glowing on the downpipe (mild steel) where it meets the exhaust manifold.

Totally common. However glowing right way without putting the car through hard duty is caused for concern.

Sorjae

i got hks downpipe and hks carbon ti cat back exhaust, both of them lite up at night.....it's pretty scary looking at it like that....but everyone seems to says it's normal....

Recipe7

i dont have a downpipe, but im sure its normal

RotorMotor

iTrader: (5)

i cant say for the DP cause its wrapped.... but after putting on the DP i noticed my turbo exhaust manifold was completely glowing after a long run!!!! this seems bad to me...... anyone else get this? my manifold already has a few nice cracks in it and im affraid this will cause many more

TwinTurbo93

Summer time If I run my car hard I keep the fan running at medium speed so the temps don't go sky high, but otherwise I don't see crazy high temps, the DP gets pretty easy red hot, I even seen the the turbo manifold getting pretty red at times.
I'm thinking of gettind some exhaust wrap for the DP to reduce at least a little the engine bay temps.

I don't have a way to check intake temps so I wouldn't know about it.

EdwardNorth

Most people seem to think that it's normal. Mine starts glowing a couple minutes after starting the car, and then disappears completely after the car is completely warmed up and the idle settles around 800 RPM. (Usually about 5-10 minutes in this cold weather)

From what I understand (and have been told by a reputable RX-7 mechanic), the car runs very rich at startup. This causes the pipe to heat up this hot, and once the mixture stabilizes the glowing disappears.

But there doesn't seem to be any "official" answer to this.

TwinTurbo93

That is such a big bull right there what the mechanic said.
You have a DP (as your sig. says) so take your car for a nice hard run at night and then just pull over where there is not much light around, open the hood and look for yourself, that sucka will be red hot, that is very normal for a turbo charged rotaries.

Hyperite

Also, running rich makes the car run colder...LEAN = hot hot hot.

SoloKK

Yup, running lean makes the car run hot.

TwinTurbo93

Yes exactly, leaner=hotter...

felix_is_alive

do any of you guys(glowing dp) have a egt gauge ,that could help
different materials react differently ,ss is known to heat up rather quickly

spurvo

And from this corner..

I too have experienced almost white hot glowing DP on cold startup, which goes away once warmed to operating temp. Lean runs hotter UNLESS you pour enough fuel in to cause combustion AFTER the exhaust ports and turbos (betcha timing get's played with too). As I understand it, this is done to heat the pre-cat quickly on startup, part of the so-called accelerated warm up, so that it will function as it's supposed too, namely to clean the cold start emissions. Any confirms?

MazdaRx7Racer4Life

I am not 100% sure on this, but someone told me that used to happen to their turbo and dp and it turned out to be thatvtheir cat was clogged. Check that out, won't hurt.