Is 3" all the way a good thing!!
#21
Former Vendor
iTrader: (31)
Join Date: Nov 2006
Location: Sunnyvale, CA
Posts: 15,442
Total Cats: 2,099
Corky's engineering goal is obviously good, since it keeps heat down, but given equal IATs, a car making 220whp at 15psi is going to be more fun to drive than a car making 220whp at 6psi or 8psi.
#22
Exhaust cools the further down stream it gets. A lot of Suby guys run 3 inch DP->midpipe into a 2.5 inch axleback. There isn't a significant difference (above the dyno error) in sub 350 whp cars when switching to a 3 inch axleback. ~5 whp difference which falls well within the dynos error.
Frank
#24
Boost Czar
iTrader: (62)
Join Date: May 2005
Location: Chantilly, VA
Posts: 79,490
Total Cats: 4,079
ben, the blast of torque when the turbo spools most likely.
fmowry, Mark probably is saying. a 2.5" with one muffler will be about the same noise level as a 3" with one muffler. all things being equal as in the components on and before the exhaust. the variable being the size of the exhaust piping.
The only reason I dropped the hat on a 3" was because I've heard one that isn't any "louder" than my 2.25", just deeper. Granted it used one large muffler, but if need be I'll add a cylinder muffler between the cat and diff.
fmowry, Mark probably is saying. a 2.5" with one muffler will be about the same noise level as a 3" with one muffler. all things being equal as in the components on and before the exhaust. the variable being the size of the exhaust piping.
The only reason I dropped the hat on a 3" was because I've heard one that isn't any "louder" than my 2.25", just deeper. Granted it used one large muffler, but if need be I'll add a cylinder muffler between the cat and diff.
#26
The way I imagine it right now is that the 15psi is like that super hot chick that is showing massive clevage and gets every guy to look at her, but if you dated her she would take all your money and be a total bitch and thinks she's amazing in bed but isn't, and just wants to party and hang out with her friends instead of you.
the 8psi sounds like a decent looking girl who dresses conservatively, but you can talk intellectually to her and she happens to be a nyphomaniac and bi-curious.
i just join the rest of the guys in checking out the hot chick with massive clevage, then turn to my girlfriend and she says "damn i'd like to see her naked"
#27
I want to see what the torque curves on a dyno look like with the same engine, but one setup at 220hp @ 15psi, and one at 220hp @ 8psi. then i'll figure out which I like best.
The way I imagine it right now is that the 15psi is like that super hot chick that is showing massive clevage and gets every guy to look at her, but if you dated her she would take all your money and be a total bitch and thinks she's amazing in bed but isn't, and just wants to party and hang out with her friends instead of you.
the 8psi sounds like a decent looking girl who dresses conservatively, but you can talk intellectually to her and she happens to be a nyphomaniac and bi-curious.
i just join the rest of the guys in checking out the hot chick with massive clevage, then turn to my girlfriend and she says "damn i'd like to see her naked"
The way I imagine it right now is that the 15psi is like that super hot chick that is showing massive clevage and gets every guy to look at her, but if you dated her she would take all your money and be a total bitch and thinks she's amazing in bed but isn't, and just wants to party and hang out with her friends instead of you.
the 8psi sounds like a decent looking girl who dresses conservatively, but you can talk intellectually to her and she happens to be a nyphomaniac and bi-curious.
i just join the rest of the guys in checking out the hot chick with massive clevage, then turn to my girlfriend and she says "damn i'd like to see her naked"
#28
The 3-inch turboback on my car does pretty much what Corky describes -- only has slight bends, and keeps the wastegate pipe separate from the main pipe for as long as possible (in this case, almost all the way into a high-flow cat).
https://www.miataturbo.net/general-miata-chat-9/pics-my-3-inch-mazdaspeed-exhaust-divorced-downpipe-10096/
Do I really need this big of a pipe for 200 rwhp? No, but it's nice headroom for when I have more $$ and build a 300 rwhp beast someday.
Oh and it sounds awesome. Not obnoxious but a really nice rumble.
https://www.miataturbo.net/general-miata-chat-9/pics-my-3-inch-mazdaspeed-exhaust-divorced-downpipe-10096/
Do I really need this big of a pipe for 200 rwhp? No, but it's nice headroom for when I have more $$ and build a 300 rwhp beast someday.
Oh and it sounds awesome. Not obnoxious but a really nice rumble.
#29
My setup is 2.5" DP and 3" from the DP back... I decided (For the looks) to go with dual exhaust, with 3" thus meaning a larger area for exhaust gases, but my design wasn't the best and I believe I have turbulence where the pipe splits... And I also added more weight, so my $0.02 would be to stay with a single pipe...
\
miatex
\
miatex
#31
15psi and 220whp makes me think late spool, and a huge, quick rise in torque near late in the rev band, whereas a 6-8psi setup would more than likely build boost much earlier in the rpm band, to perhaps a lower peak torque, but much more flat. I guess you could have a quick, early spooling 15psi setup only reach 220whp, but it's be horrible inefficient/poorly tuned!
#34
It wouldn't necessarily poop out in the upper RPM range. It's got a turbocharger, so boost pressure is controlled. This means, as long as you're not out of the flow range of the 'charger, torque curve should remain relatively flat.
There are so many variables, though, it's silly to make sweeping statements like these.
There are so many variables, though, it's silly to make sweeping statements like these.
#35
a decent looking girl who dresses conservatively, but you can talk intellectually to her and she happens to be a nyphomaniac and bi-curious.
i just join the rest of the guys in checking out the hot chick with massive clevage, then turn to my girlfriend and she says "damn i'd like to see her naked"
i just join the rest of the guys in checking out the hot chick with massive clevage, then turn to my girlfriend and she says "damn i'd like to see her naked"
Well there's one thing to be said though. If you can make 220 hp on 6psi you probably have a much safer engine. Besides, no one is going to think you are a tuning guru if you can only make more hp by blasting the **** out of psi. If you have over 1 bar of boost you better be making at least 350 hp and in my opinion..more than that.
#36
Well, it goes without saying that if you and your buddy have the exact same turbocharger setup, but he's making 220rwhp out of 10-12psi and you're pushing 15psi to make the same 220rwhp, either you're engine is tired, you're tuning too conservatively or he's tuning to aggressively.
It obvious that you'd want the most amount of power per PSI without sacrificing spool.
It obvious that you'd want the most amount of power per PSI without sacrificing spool.