2.5 or 3 Inch Exhaust??

[importwarrior]

Maybe i am wrong. BUT the whole idea of getting the 3 inch was to eliminate back pressure AFTER the turbo

to better spool.

the presure between the head and turbo along with the heat of the exhaust spool the turbo buy openning the exhaust behind the turbo

you help the flow of exhaust out of the system with less pressure to aid in faster spool by less back presssure and less restriction on the turbine.

i think?????

Edited July 25, 2013 by importwarrior

[Dred_85.5_TSI]

Yeah back pressure on a turbo car is a bad thing.

[Cloud81918]

Back pressure is widely know to be a myth anymore. The issue isn't backpressure, you want to avoid all back pressure is possible. The issue is velocity. Going too big will mean hot fast moving gasses will run into stagnant lazy cooling gases.

 

I have 2.5 inch on non-NA cars under 2 liters in size. I will admit it is a bit too big, but more of an issue of weight than any other performance measure,

 

There are lots o way to look at engines. It sometimes helps to look at a turbo engine as a NA engine. Basicly producing an extra atmosphere of pressure will double the total flow through an engine (not really, but it is a simple model). Playing with this model a 2.6 pushing nearly 15 PSI is basically moving the same amount of air as a 5.0 if both are at the same RPM. People run 2.5 inch dual exhaust on small block Fords all the time. So I think if you have plans for anything like that you are probably choking the engine a bit with a single 2.5.

 

If you are at 7 PSI. Using that model practice again, a 2.6 at about 7 psi should be seen as about a 4 liter engine. Is 3 inch exhaust pipe a bit big.

 

My goal is the 300+ club. I needed an new exhaust and didn't want to buy twice. In current stock tune all I see from it is faster spool and louder exhaust. I doubt I've added much power. Probably haven't broken 200hp, other mods in the mix as well. As I said gunning for 300, if I had got to 280 and was on a 2.5 inch I would have been kind of irritated with myself that I didn't go for 3.

 

I think you will be happy with the MK1.

Edited July 26, 2013 by Cloud81918

[RonnieJ]

Under 400whp 3" downpipe to 2.5" catback is fine. shop FRS made 400whp with a 3" downpipe 2.5" catback and high flow cat. If you dont want the added noise and drone do this

 

Edited July 25, 2013 by RonnieJ

['87quest]

someday I too want to join the 300+ club as well

[traps]

I am guessing turbo lag is a myth too.....but with new turbo technology and variable vanes and vane position sensors who needs lag with a 25 yr old car. bigger isn't always better when your looking for fast spool. Once again ask yourself...track car, daily or stoplight assasin. My porsche had open headers and after " no back pressure" the valves bent and even my mechanic warned my from running her the way I did all the time. Is restriction what we are gettin rid of from our overdone oem vehicles yes but am just adding two cents

[Fuze]

I hear guys debating backpressure. All you have to do is bolt on a downpipe and see the difference created from the reduction in backpressure, it's obvious. When is too little backpressure a problem on a turbo car? Never. The faster the exhaust can leave the car, the faster the spool.

['87quest]

Installed my mk1 exhaust and downpipe and had my local guy build me the missing pipe. Love the 3in exhaust!

[importwarrior]

Glad to hear it

Thanks for the update. did you notice anything better or worse now that you have a 3 inch?

[Fuze]

Installed my mk1 exhaust and downpipe and had my local guy build me the missing pipe. Love the 3in exhaust!

 

Good deal. It's the last exhaust you will probably need to buy regardless of whatever else you do.

['87quest]

yeah you can really feel a pretty good power gain and acceleration is much better.. It totaled around $500 but i figured if I'm going to do it why have to do it twice.. I'm very happy with it.. looks better, sounds better, more power = happy owner

[krudmuphin]

I might get the same setup as you after reading through this entire old thread today, lol

 

Do you have a sound clip of you 3" setup?

Although I'm assuming it sounds like a tractor just like every 2.6 Starion anyways (not a bad thing, haha)

Edited August 9, 2013 by krudmuphin

['87quest]

No I don't.. it sounds pretty good.. kinda cackles a bit when you let off which sounds cool haha

 

Want me to go take a video of it for you? Or can I not even upload a video here?

[Force Fed Mopar]

A video would be great I have a 2.5" turbo back exhaust on mine, no cat and a wore out Greddy muffler that drones bad. I'll leave the 2.5" pipe on it but need another muffler bad. A vid and description of yours would be helpful. I have been considering a Magnaflow.

['87quest]

Alright I'll try to get a video up today

[krudmuphin]

Sweet! YOu can always post it to youtube or another video site and just link the video. I'm not sure if this forum supports uploading video files...

['87quest]

Well here goes.. I hope it works! Haha I don't know if it's my phone or what but it's much smoother in person

 

http://i1321.photobucket.com/albums/u560/drakelehr/th_20130810_090215_zps5fe29f5d.jpg

[Force Fed Mopar]

You need to stand 30-40 ft away when recording with a phone to get decent sound, the mics are too sensitive and make it buzz like that when close up.

[Technology]

Here's a couple lame videos I made, it's interior, but you can hear the exhaust. It's 3" with only a magnaflow 3" offset in/out and the tip extends about 2-3" past the bumper. It was really reasonable inside.

 

 

 

Don't mind that dang fuel pump or the commentary (lol) in the second video, but you do hear the sound from the hatch area since the camera was there.

 

Setup was a 292 cam, larger turbo, MPI, but stock head and cast log manifold.

 

For bigger power, remember, you drive the turbo, and no matter what people say, there's still a trade off, the bigger the turbo, the more lag you'll have, but for only 300 HP, you don't need a huge turbo, any 16G will get you there. It's always going to be easier with MPI, but just adding a big turbo will give you the right starting point.

[TexasQuest]

Wow 3 inch is a lot quieter with a muffler lol. What kind of fuel pump is that?

['87quest]

Here's another video from a bit farther away.. you can hear the exhaust and you can see that it sounds good, not annoying like some other ones I've heard

 

http://i1321.photobucket.com/albums/u560/drakelehr/th_20130813_141645_zps7859c179.jpg

[Technology]

That was the Aeromotive A1000. I swapped to dual walbro 255s after that. It was a million times better.

[krudmuphin]

Wow that's loud. But I probably want to get the same setup for mine! Loud is good

 

I would get a different muffler though. I like the looks of the stock dual-tip muffler.

['87quest]

Yeah I like the dual tip better too but this came in the kit.. I'll change it when I find a few bucks haha

[PhenomTSi]

My '87 has a 2.5" (no cat) with a Dynomax muffler and I can hardly hear it when cruising, but it gives you a nice growl when you get on it.

My buddy's '83 has a 2.5" (no cat) with a Borla muffler and it's much louder, but still doesn't sound too droney (spelling? LOL).

 

Either way will definitely give you a performance boost, but like most people have said, 2.5" is plenty unless you plan on doing quite a few more mods later on.

Just my .02 cents