Is a 2.5" full exhaust with E3 16g ok?

[desant78]

Hello gvr4.org

I have upgraded to a E3 16g, and when I went to install my 2.5" DP, the flange did not fit. This forced my hand to use the full 3" exhaust I have. Unfortunately, while it bolts up it's stupid loud. With a e3 16g pushed, from 18 to 22psi, am I going to see a major advantage using the 3" over 2.5"?

I'd prefer the 2.5" because it' smuch quiter, and the 3" is VERY low to the ground, while the 2.5" is tucked very nicely.

As always, opinions appreciated.

thanks again!

 

[LIV4PSI]

Go with a 3in downpipe, and a 2.5in catback. The downpipe is what makes all of the power. Or you could always add some resonators or switch to a quieter muffler.

 

[DynastyLCD]

i used a 2.5" turbo back on 73, no ill issues. i was using an external wastegate though.

i don't think it would be a huge downgrade with your setup really

 

[Ian M]

I remember way back in the day,at least one person with a GVR4 running in the 12's with a "3in downpipe and the stock catback. I doubt you'll see any real gain with "3 versus "2.5 on a avaerage 16g setup.

 

[ktmrider]

Quoting desant78:
I have upgraded to a E3 16g, and when I went to install my 2.5" DP, the flange did not fit. This forced my hand to use the full 3" exhaust I have. Unfortunately, while it bolts up it's stupid loud. With a e3 16g pushed, from 18 to 22psi, am I going to see a major advantage using the 3" over 2.5"?

Did you also install an E3 O2 housing?!? If so the DSM/MMC O2 flange angle is different as you likely have found out. Some DP's fit, some do not, no rhyme or reason to what works.

I also assume you're non-catted, a nice HF cat will quiet things down hugely and be better on the smog stuff too.... /ubbthreads/images/graemlins/wink.gif Otherwise get a resonator or cherry bomb muffler in the cat position to help knock the dB's down.

 

[5OF2k]

Id personally keep the 3" and do the cherry bomb/resonator/HFcat thing if I were you. It does make a difference, FWIW. Whatever tickles your pickle though, I suppose.

-Jake

 

[rdomeck]

I am currently running a full 3" with an eve 3 16g and it was load enough to get pulled over and handing a warning. I drove it into my shop and installed the new cat that I had on the shelf and although quieter it does not spool as fast as it did. I will be ordering a resonator soon to replace the cat and maybe getting a better high flow cat. I believe the 2.5" to 3" you will notice a difference. I am also using an evo 3 manifold and O2 housing.

 

[turbofonz]

Full 3" with just the CM muffler and my Galant isn't loud at all, IMO, of course. A resonator or cat would make it very quiet for being such a big exhaust.

At 18-22psi, I think that's right where you'll be seeing gains from a full 3". Guys have run fast on smaller systems, but it doesn't prove anything.

 

[5OF2k]

Agreed.

Im running an E3 at about 26lbs and have a full 3" with a high flow cat and a tiny vibrant bullt style straight through muffler, no resonators or anything else and it's not all that loud, and it definitely makes a difference over the 2.5". Even running open downpipe alone makes a massive difference from that, for what its worth. It all boils down to your goals, and honestly, once you have an upgraded turbo, you're going to want to go even further with the car at some point power wise. Keep the 3", it'll be worth it in the long run. Besides, turbo cars LOVE to breathe. Period. Even on smaller turbos like the factory and 16gs...

Then again, i happen to be a firm believer and quite fond of the 4G63 exhaust note, and plan to remove my cat shortly. Then, it'll be loud. But the good kind of loud, if that makes sense?

-Jake

 

[turbofonz]

Now that I think about it, with my 1g, going from a 2.5" downpipe/HKS 2 3/8" catback the car would trap 112mph. Putting a 3" turboback on the next time out the car went 116.5. This was a big 16g at low 20's psi but that's the only specifics I remember. The car's best ever on a 2.5" exhaust (full buschur) was a 12.0@113mph, but the next year I swapped the intercooler (and was running that HKS catback in the winter). The Buschur 3" woke the thing the f*** up.

But the Buschur on my Talon is loud. Even with a resonator, it's a good deal louder than my galant. And now that it has a 30r, its just that much louder lol.

Just from my experience

 

Quoting 5OF2k:
Id personally keep the 3" and do the cherry bomb/resonator/HFcat thing if I were you. It does make a difference, FWIW. Whatever tickles your pickle though, I suppose.

-Jake


+1

 

[desant78]

Quoting 5OF2k:
Agreed.

Im running an E3 at about 26lbs and have a full 3" with a high flow cat and a tiny vibrant bullt style straight through muffler, no resonators or anything else and it's not all that loud, and it definitely makes a difference over the 2.5". Even running open downpipe alone makes a massive difference from that, for what its worth. It all boils down to your goals, and honestly, once you have an upgraded turbo, you're going to want to go even further with the car at some point power wise. Keep the 3", it'll be worth it in the long run. Besides, turbo cars LOVE to breathe. Period. Even on smaller turbos like the factory and 16gs...

Then again, i happen to be a firm believer and quite fond of the 4G63 exhaust note, and plan to remove my cat shortly. Then, it'll be loud. But the good kind of loud, if that makes sense?

-Jake



exactly what I am pursuing here, the "good" kind of loud. I think i'll just cut up the 3in so ti's tucked better, add a vibrant muffler (vs. the magnaflow) and if i'm still un-happy, add a resonator and perhaps *gasp* hi-flow cat.

thanks! I'll post up results, but thats far in teh future, until then ima drive this thing /ubbthreads/images/graemlins/devil.gif

 

[ghostinthevr4]

Go 3 inch and never look back, here's a lil trick. If you want the exhaust note quieter get an aluminized exhaust, stainless are louder than aluminized. Many moons ago I had a 1g with a buschur 3 inch it was pretty loud but I loved it. With my galant I have a CMP exhaust system and its aluminized, I didn't want to pay extra for the stainless. After the install the first thing I noticed was the difference in sound.

The stainless will sound louder and will crackle more. The aluminized has a lower deeper tone, it worked out great for me because I try to keep the car on sleeper status.

 

[4thStroke]

3" downpipe with an eBay wastegate mounted to it that vents to atmosphere, set to open at a low pressure (a lot of them are adjustable, too), then a small catback from there. That way you get the flow of the 3" and the open dump off the downpipe, but the car will be quiet while cruising around out of boost (or low boost, as long as you are below the point where the wastegate opens).

Adding a cat may or may not help. While others say they have seen a big difference in noise, I saw little to no difference. I used a Magnaflow high flow cat in my 3" setup and notice almost nothing. I'm sure there are cats that will make more of a difference, however. But, placement of the cat and/or resonator will also make a difference. Tuning an exhaust system is not as simple as throwing mufflers, cats, and resonators into the exhaust systems and assuming you've quieted the exhaust down as much as the given number of pieces will allow.

 

[DynastyLCD]

Quoting turbofonz:
But the Buschur on my Talon is loud. Even with a resonator, it's a good deal louder than my galant. And now that it has a 30r, its just that much louder lol.

Just from my experience




very interesting, Fonz. i had the FPgreen in the stock bolton housing on my blue car, with the FP race manifold and a 3" exhaust... it was really loud. like, almost obnoxious loud. but when i bolted my 30r back on, it actually quieted it down a great deal