hey im about to redo my exhaust system on my supercharged 2.4 and im still running the stock 4.5-5psi and everyone's been telling me to get rid of my 2.25" catback and get 2.5", is it really gonna make that much differance or what? thanks cause im wondering.
hmmmmm yea. it'll be really noticable when you have a smaller pulley making like 8 or 9 psi.
I was a retard, and now I'm permanently banned.
listening for anyone else whos got comments on this
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- Sold my beloved J in April 2010 -
I'm swapping mine in a few days. I have a hahn kit on
an ecotec. I"ll let you know
In my case...
I have 2.5in all around now on the stock dual mufflers w/28in resonator.
I had the dynomax super turbo with the 2.5 in mandrel pipes. Those mufflers were loud as hell in the cabin, my gas mileage dropped from 21-22City to 18city (yes with the easiest driving so I would not hear the resonance). My low-end torque was gone, top-end hp suffered slightly too but not as bad as the low-end tq.
After like 5 days I told the muffler shop to put my stock mufflers back. First... peace and quiet with a better tone (ty 28in resonator). Drove it back out, the low-end torque was better then ever, traction became an issue again lol. Top-end improved slightly. Best of all I am doing consistently 22mpgs again.
Moral of the story and in my case 2.5in (maybe) to big on the S/C, not so on the turbo though. What I have is like a hybrid: 2.5in mandrel pipes on the stock 2in muffler and 1.75in little muffler. With this combination it is working better then ever.
You know, 4 muffler shops all said the same, don't want to go to big and you want to have some sort of back pressure, in the end they were all right.
Stay with 2.25in, honestly I think that is the optimum size for the standard GM S/C unit.
Thats my experience and suggestion.
Good luck.
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
at least the mufflers were cheap in price.
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- Sold my beloved J in April 2010 -
^True, I had a rebate to go along with it too. I got to sell both later and at the same price I paid for.
When my friends put it on their cars (04 Galant & 00 Accord), the mufflers were quiet and exactly how I wanted it to be. Go figure, I guess the super turbo does that on the auto tranny as on the sound clip you sent me was quiet too.
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
well first of all, you're using duals, and secondly, perhaps the stock header creates an odd flow when transfering to a 2.5 piping...
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- Sold my beloved J in April 2010 -
I also have a pacesetter header, Vortech Supercharer with 2.25" exhaust all the way back.
Seems to be the perfect set-up running close to 8PSI
ive got all 2 1/4"pipe i had it before the s/c went on , and the s/c has been on since sunday
it runs really good , so i doubt ill change it to anything else , other than adding a resonator , and maybe changing out the magnaflow muffler for a different 1 so its quiter out side , ive got the rk single cat back
Well friends, now I am really confused with this info. Please can you elaborate why a 2.25" exhaust will be the optimal exhaust for supercharged LD9? Or it will be enough at it limit for stock SC engine seeing 4-5psi with the stock 2.8" pulley? so what happends if I will like to install a smaller pulley like 2.6" looking for 7-8psi and more power? the same 2.25" will begins to be a restriction? Maybe this is the fact that I can conclude about the words of Mr.Goodwrench-GT.
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MAKING MY DREAMS A REALITY
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ELIOT. Now.....boosted.
2.25" is TOO RESTRICTIVE in even a n/a application. We dont have small 1.6 - 2.0L motors here. For a 2.4L motor 2.5" exhaust is optimal. It has been DYNO proven.
I dunno how many times I have to post this.
blue is stock, red is 2.25, green is 2.5"
Notice more power AND torque? Now just think if you had a blower on your car as well. I convinced the guys with spec v's of this as well as they THOUGHT 2.25" was right for there car and they have a similar size motor (2.5L).
2.25" is gonna be a upgrade from stock sure, but your not gonna get the full power you need... and you WILL choke your blower, especially with a smaller pulley.
like BlackZ2401 said^^^^...2.5" is the way to go. and you dont want any backpressure at all no matter how many muffler shops tell you that you do. backpressure is the worst thing for an exhaust system. you want the most free flowing exhaust you can get with the proper pipe size to maintain velocity. and with superchargers, or any forced induction for that matter, the air is forced into the cylinders so the engine doesnt have to rely on the exhaust gas velocity exiting the cylinder to pull in the intake air. plus there's a lot more exhaust to get rid of from a boosted engine than a N/A engine, so you can go even a little bigger with the exhaust piping.
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450WHP Turbo Ecotec swap in the works...
you know funny thing about a dyno
they dont really tell you real world daily stuff , just cause it shows you a increase on the dyno , doesnt mean you will make power on the street while daily driving
[quote=97cavie24ls(JDM&00s/c sedans™)]you know funny thing about a dyno
they dont really tell you real world daily stuff , just cause it shows you a increase on the dyno , doesnt mean you will make power on the street while daily driving
First. Very well said.^^
Second I am not go out here and argue on what I have expirianced to a product dyno sheet. If you want to go really big on the exhaust go ahead. I went to the exhaust shops with a similar mentality that with the standard GM boost would increase power, when in the end the power was immidiatly felt was less, with that that came MPG decrease that was just unjustified.
Maybe if you are running on boost all the time with the standard psi you may see a gain (I certainly did not) or maybe if you are running 8psi, the 2.5in pipes maybe more favorable, but in my case it was a waste of money.
Still say 2.25in is the way to go if you want to maintain low end torque, increased top-end HP and still have a appropriate MPGs. Again that is my suggestion from my expiriance.
>>>For Sale? Clicky!<<<
-----The orginal Mr.Goodwrench on the JBO since 11/99-----
OK my 2 Z24's that Ive had I ran 2.5" piping with next to no other mods (intake and throttle body) and guess what I still had all my low end and gained a good amount of top end. My friend with a spec v went from 2.25 to 2.5" and it made a nice noticable gain in the top end of second adn third gear especially.
Now when I had my 1.6L civic si, then yes I used 2.25".
I mean I really dont care what you guys do its not my car and doesnt affect me any, but 2.25" IS TOO SMALL for our motors
[quote=97cavie24ls(JDM&00s/c sedans™)]you know funny thing about a dyno
they dont really tell you real world daily stuff , just cause it shows you a increase on the dyno , doesnt mean you will make power on the street while daily driving
Ok that statement really confused me...so you're saying that even though it SHOWS a power increase on a dyno...you mean to tell me you won't make that power on the street? Or are you just talking about a daily commute...not taking the car into boost?
Either way doesn't make sense to me.
I'd rather go ahead and get 2.5" anyway....2.25" might be fine if you plan on just running the s/c and a few bolt ons. But if you plan on getting some good numbers from the M45 LD9, then 2.5" would be your best bet.
