Freebs

iTrader: (1)

Just wondering who is running the Greddy Spectrum Elite SE exhaust as I have a few questions

1. Being that it is only 2.75" vs. the 3" that most of the other companies offer, has anyone done a before and after dyno with this exhaust?

2. How is the interior drone? Let me know what downpipe and cat/test pipe you are running since these (mainly the cat) seem to be the factor that gives an exhaust system its drone or not.

raytrix

iTrader: (12)

Please check out my review. With test pipe and with stock cat.
https://www.evolutionm.net/forums/ev...pe-review.html

Freebs

iTrader: (1)

WOW! thank you.. Everything I needed to know
Only thing that I don't understand is how you said you had more low end with more back pressure. A Turbo charged engine with back pressure will make less low end because the turbo can not spool up as quick inturn can not produce as much power in the low end. Even more on the Evo which has TERRIBLE low end


Only thing that bugs me about this exhaust is the 2.75" diameter, because I know how much more that 0.25" can flow. But will the 2.75" tubing be ok to reach my 350-375whp on a mustang dyno goal...

raytrix

iTrader: (12)

I don't see any point in going 3" or higher unless you plan to make a drag car out of your evo. 2.75" is good enough for autox-ing and street driving. 2.75" should net you upto 400-450whp before you need a bigger exhaust for more flow. The backpressure is a terrible analogy that I made in that review. All i know is the way the Greddy SE was designed seemed to gave the car better low end response vs the HKS Hi Power exhaust which had straight through piping with no resonator and just a muffler at the end.

raytrix

iTrader: (12)

read this thread. Has everything about back pressure compared to hole size.

http://www.fullsizechevy.com/forums/...st-piping.html

http://www.fullsizechevy.com/forums/...ckpresure.html

350z forum
http://www.the370z.com/intake-exhaus...c-exhaust.html

Freebs

iTrader: (1)

Thoughts links have nothing to do with a turbo charged engine though. With a turbo charged engine the less back pressure you have on the turbine the easier it is for the turbo to spool up there for you are making power faster. A 3" diameter pipe will flow quite a bit more than a 2.75" even though it doesn't seem like that much of a difference.

Being that the Evo X could use all the advantage it can get for low end pick up and even more so because I have an MR which is the worst of the 2 for bottom end/off the line get up and go. When I ran an open down pipe on my other turbo car (just a tube straight off the turbo pointed out the side of the car) that turbo spooled up incredibly fast compared to when I had a exhaust system bolted up.

I think the Greddy exhaust is incredibly nice and has a very nice tone to it, but I think it will hold me back to some extent, maybe not in peak hp numbers but if there is one thing I have learned over the years of building fast cars is that it’s not always about peak power numbers but how you get there, power under the curve so to speak.

EVOFreak27

You have it backwards. A smaller pipe diameter will create more backpressure which will hold you back on the top end but will give you better torque in the bottom of the power band. A 3" pipe will flow better up top and net you better top end while sacrificing a little bottom end. This is the same idea with turbochargers. Generally and smaller exhaust housing will net you better torque gains while sacrificing some top end because the higher pressure in the exhaust housing will spool the turbo faster but the backpressure will slow exhaust flow on the top end. A larger exhaust housing will flow better up top with very good top end power but will take longer to spool due to the lower pressure not being able to spool the turbine as quickly.

Freebs

iTrader: (1)

I am sorry a smaller exhaust on a turbo application isn’t going to give you better low end. Smaller turbine housing would, but not a smaller diameter exhaust.

Again less back pressure in your exhaust system will allow the turbine to spin up easier thus making more power in the low end because you are going to see more boost at a lower RPM. You stick a smaller diameter exhaust on and your turbine isn’t going to spin as freely and there for you will not create boost as fast in turn you won’t create as much low end pull. I could see smaller tubing used in the turbo manifold to create more velocity threw the turbine but that’s about it.

Lonestar

I just had my Greddy SE removed in favor of the single JIC Ti-sus, with resonator. When I set out to purchase the Greddy, I was looking for more performance and definitely more sound, more edge then the stock piece. I can't tell you how disappointed I was with the Greddy piece, the only time I could hear was when standing right behind it. It looks amazing from most angles but the way the tips taper looks awkward sometimes. A show piece to me but I also still have stock cat and DP. JIC is magic, silencer in louder than greddy but not great sky tearing sound at around 6K rpm, w/o silencer the car rumbles, and screams. Haven't had one person complain of it being too loud inside the car, including geriatrics...but with test pipe/ DP that could be another story, oh and this new pops alot more between shifts and on overun which I love.