any feedback is appreciated!! good or bad

I am thinking to have 2.5 inch full custom mandrel bent exhaust with a resonator and a dynomax super turbo muffler... from what i have read, that muffler is the best for quietness and high flow capabilities

i am running a garrett 60trim turbo with a 38mm tial wastegate, and i heard the less back pressure the faster the turbo spools up and the better it is for the turbo's "life span"...

my concern is this idea having to much backpressure and being to restrictive, and i dont want to have another exhaust made, ever! lol.... i plan on running 15psi after getting all the supporting mods, and later this year fully building the motor and running about 20-25psi or maybe less and run nitrious... im hoping for around 300-350whp, and of course my project will never end

I was not sure if i should run an open dump because its only 2.5" and not 3" (like i am now, but im having it atleast re done because of exhaust leaks and a poorly constructed garage built downpipe) except i would add a resonator this time around...

do you guys think 2.5 would be good enough to last me, or if i should get the 3"? or is 3" overkill for our cars?

i have done my reading, i read the faqs, and i searched this forum and the performance forum, and i do kno 20-25psi is a lot and dangerous, i am asking about my specific setup and what you guys think

p.s. im not sure if its a good analogy, but my friends srt4 makes 300+whp on the stock exhaust which is 2.25", he has a cut out, but he dyno'ed with it closed at 300+ i forget the exact number, but i think it was high 300s

http://www.j-body.org/forums/read.php?f=40&i=106367&t=106367#106367, most threads in performance dont mention if its good for turbo applications



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

Typically, you don't want an exhaust (for your application) smaller than 2.5", so you're off to a good start. I have the same EXACT exhaust setup you outlined in the second section and it sounds amazing!

But if you really want to boost as high as 20-25psi and don't ever want another setup installed, I would absolutely go with at least a 3" exhaust. You're right about the "bigger exhaust = faster spool up" and when you're putting out that type of pressure, you definitely want your car to breathe.

The one thing I think you're way off about is your hp goals on that high a boost. I have a video of an eclipse running 24 psi and putting down well over 550 h.p. If you do it right, you should be WAY above what you're planning.

i like to think low so i get more then i am expecting.... plus, 550HP Ecotec... is there even one on here?!?!!?!? that would be awesome... lol

you think a 2.5" open dump would be equvialent to a 3" full exhaust? or does it not work that way? im just thinking because of the extra restriction the 3" would have being a full exhuast system....

up to what hp/psi would the 2.5 full exhaust be good for? and up to what psi/hp would a 2.5" open dump be good for?

sry if the questions are newbish... i think they might be i just want to make sure exactly what im getting into, thanks again

nice sunfire agent omega...



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

2.5" will be fine... dont bother going open dump... you dont gain any thing to make it worth while trust me... i had a 3" turbo back with a dump and it was usless... i scraped it and went back to a 2.5" turbo back ... my opinion after having 4 different exhaust set ups on my car... ranging from stock to 3" i would say 2.5" is perfect for our cars... 3" is a waste... the air unless your pushing over 350+hp does not flow properly as i was told by the performance shop who makes my exhaust... who also adivesed against putting the 3" on but i did it any way as it came with my turbo kit... think of it this way... our 02 ws6 trans am that dynoed at 318whp bone stock.. and it came with a 2.5" exhaust which flowed perfectly for the power it was putting out... so unless your putting out big hp numbers 2.5" is more then enough...



The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno

thanks for the input!!

sexy twin charge idea by the way, good luck with that!!!



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

The bigger the piping the better for a turbo car...you almost can't go too big. The more restriction you can get off the turbine the quicker it'll spool, producing more low end power. Then the larger piping also flows better at high rpms, producing more high end power. So you get gains throughout the entire rpm range. Go with 3"...especially if you're planning on pushing more than 20psi and over 300hp.....that's a whole lot of air to flow. I personally have a 3" turbo-back on my turbo 2.4 pushing only 8psi and I've been completely happy with it. Just make sure any mufflers or resonators you use are stright through perforated core for the least amount of restriction.


_________________________________________
450WHP Turbo Ecotec swap in the works...

Spilner521 wrote:The bigger the piping the better for a turbo car...you almost can't go too big. The more restriction you can get off the turbine the quicker it'll spool, producing more low end power. Then the larger piping also flows better at high rpms, producing more high end power. So you get gains throughout the entire rpm range. Go with 3"...especially if you're planning on pushing more than 20psi and over 300hp.....that's a whole lot of air to flow. I personally have a 3" turbo-back on my turbo 2.4 pushing only 8psi and I've been completely happy with it. Just make sure any mufflers or resonators you use are stright through perforated core for the least amount of restriction.

x2. this guy knows what he's talking about, 3" is not overkill on a turbo car

well... i have decided to go with the 2.5" back exhaust with a 3" cut out....

is this a good muffler for a turbo application? MPE-12265

http://store.summitracing.com/partdetail.asp?autofilter=1&part=MPE%2D12265&N=4294922711+400636+115&autoview=sku

yea, im gunna get dual tips for no reason but looks and to spend more money!

im guessing its good because in the description for it says that its a straight through design for unrestricted flow just wanted your opinions on it... i was going to go with the dynomax superturbo but the dual exhaust version doesnt have the outlets like this one and im hoping to install it like the camaros do... http://www.j-body.org/forums/read.php?f=2&i=361139&t=361139 , http://www.j-body.org/~dave/exhaustpics.html

let me know what you think about brand, use for turbo application, size, sound, performance, all the good stuff...



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

So, that'll be 3" up until the point where the cutout is and then 2.5" the rest of the way back, right?

yea... so when i open the cut out i have the 3" dump and when i bolt it shut i have a 2.5" full exhaust with a resonator and muffler....



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

i dont think its a good idea to shrink the exhaust.

if i were you, id go 2.5 with cut out for now. then when you build the motor and up the boost. if you so desire, or think you need it, go with the 3 inch with, or without a cut out, and you can some of the money for that by selling the 2.5 system.