Fat or slim? (Exhaust decision)
01-18-14, 09:12 PM
#1
Fat or slim? (Exhaust decision)
So today I went to put on a single n1 apexi muffler. With out doing much research at all, I chose a 2.25 piping from the last cat to the muffler.
The performance is stellar, heel toe like a boss, revving much better, still keeps plenty back pressure.
My question/ problem is that I noticed the exhaust get much much hotter than stock. MUCH. Should I be worried? heat shield it more? Increase piping size to 2.5 like all other after markets?
What should I do?
If you have stories, it'll help.
thanks.
The performance is stellar, heel toe like a boss, revving much better, still keeps plenty back pressure.
My question/ problem is that I noticed the exhaust get much much hotter than stock. MUCH. Should I be worried? heat shield it more? Increase piping size to 2.5 like all other after markets?
What should I do?
If you have stories, it'll help.
thanks.
Last edited by misterstyx69; 01-22-14 at 10:19 PM. Reason: spelling in title.fixed.
01-19-14, 03:38 AM
#4
I felt the air coming out was super hot. Even like a good 8 inches away my hand was barely able to with stand the heat.
I was wondering if airflow wasn't passing through thoroughly enough and getting caught and heating up way more that it's suppose to.
Never had an exhaust on this car.
I was wondering if airflow wasn't passing through thoroughly enough and getting caught and heating up way more that it's suppose to.
Never had an exhaust on this car.
01-19-14, 09:51 AM
#5
MECP Certified Installer
When you say air, do you mean the exhaust coming out of the pipe?
If so, I would chalk it up to higher exhaust gas velocity. Lower exhaust gas velocity means it stays in the pipe longer and cools.
If so, I would chalk it up to higher exhaust gas velocity. Lower exhaust gas velocity means it stays in the pipe longer and cools.
01-19-14, 10:43 AM
#6
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The temperature at the header is typically about 900F at idle and about 1,700F at full load. The metal in the exhaust system absorbs some of this heat, but the output at the tail pipe is still extremely hot. This is why you don't want to park your RX-7 over dry leaves or tall dry grass. 
01-20-14, 01:35 AM
#7
And that would make sense.
I just thought it might be something to do with too much pressure making the temperature extremely hot or something.
The temperature at the header is typically about 900F at idle and about 1,700F at full load. The metal in the exhaust system absorbs some of this heat, but the output at the tail pipe is still extremely hot. This is why you don't want to park your RX-7 over dry leaves or tall dry grass.
But okay I see. Thanks for the data.
I'm guessing that the old stock piping was just REALLY good with cooling down that air and not letting it all come out at once.
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01-20-14, 10:16 AM
#8
MECP Certified Installer
If your butt dyno says the new exhaust is good, than keep it.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
01-20-14, 12:04 PM
#9
I put a racing beat header and went straight back into 2 magnaflows on my 88 n/a, even when its first fired the exhause coming out've the mufflers is HOT, so its to be expected. Gotta remember too that a rotary runs hotter than the piston counterpart
01-22-14, 12:43 PM
#10
If your butt dyno says the new exhaust is good, than keep it.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
I'm that type of owner who gets worried when the slightest thing seems off.
01-22-14, 12:49 PM
#11
If your butt dyno says the new exhaust is good, than keep it.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
The stock muffler are good at slowing the exhaust down. Also, since you went single exhaust, its all coming out of one pipe now. Don't worry about it being hot, you want it to be hot and coming out as fast as possible.
a 3" single exhaust with Borla XR-1 puts down nearly the same as the stock dual catback does at 300-325whp. perhaps the cans are blown but you still can't hear the car from 2+ blocks away so i doubt it. i actually keep the stock catback on my car more than it sees the single these days, it's quieter than even the racing beat duals but i'm sure the stocker is restrictive quicker than they are.
Last edited by RotaryEvolution; 01-22-14 at 12:53 PM.
01-22-14, 09:49 PM
#12
the stock exhaust is good at absorbing sound waves, it is actually not a huge source of restriction.
a 3" single exhaust with Borla XR-1 puts down nearly the same as the stock dual catback does at 300-325whp. perhaps the cans are blown but you still can't hear the car from 2+ blocks away so i doubt it. i actually keep the stock catback on my car more than it sees the single these days, it's quieter than even the racing beat duals but i'm sure the stocker is restrictive quicker than they are.
a 3" single exhaust with Borla XR-1 puts down nearly the same as the stock dual catback does at 300-325whp. perhaps the cans are blown but you still can't hear the car from 2+ blocks away so i doubt it. i actually keep the stock catback on my car more than it sees the single these days, it's quieter than even the racing beat duals but i'm sure the stocker is restrictive quicker than they are.
the stock is definitely good at absorbing sound. I think since it is SO good at trapping the sound in the can, that it does create a bit of restriction.
And also, I'm guessing since all the filling in the can is slowing down the air, its getting time to cool and lose velocity when flowing out; which is probably why it wasn't nearly as hot as now.
At least this is what I interpreted from the poster above
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