How much power will stock ALH exhaust support?

Mike_D · Apr 13, 2016

I know that the least amount of restriction in the exhaust the better. But, I like this car as quiet as possible. I do have a kerma downpipe now, but don't want to make any other mods to the exhaust if not necessary.

How much hp will the factory exhaust (with an aftermarket downpipe) efficiently support?

Fix_Until_Broke · Apr 13, 2016

With or without the feline? The muffler does next to nothing for sound in and of itself. If you leave the cat in and cut the muffler out you may not even notice.

If you run no cat and no muffler, it will definitely be louder, lots of turbo whistle, and likely a drone on the highway depending on what you do for a tip.

I've got data somewhere (can't seem to find it now) that I took with an OEM downpipe and CAT vs my 3" downpipe, no cat.

If I remember, there was a ~7psi difference in pressure in the downpipe on a ~150HP setup at the time.

Mike_D · Apr 14, 2016

No feline.
If I understand correctly this down pipe with the stock exhaust should be good around 150hp? 160'ish hp is probably as far as I will go.

Fix_Until_Broke · Apr 14, 2016

Support is really hard to define.

With no cat, I'd think 160hp would not be a problem on stock exhaust and larger down pipe.

The cat and down pipe are probably the most significant restrictions.

john.jackson9213 · Apr 14, 2016

Just for what ever it may be worth:

I am running a 2.5 inch down pipe to the stock convertor. From the convertor back is completely stock with all 3 factory mufflers and the stock pipe diameters.

My ecu has 2 different tunes: My low smoke tune measures 162 hp 285 ft/lb torque. My higher smoke tune measures 173 hp 313 ft/lb These numbers are at the front wheels, on the dyno. Neither one of these tunes is set for maximum horsepower.

Mike_D · Apr 15, 2016

I think I will just leave the exhaust alone. Sounds like it should be fine. Thanks for the feedback.

millere5815 · May 10, 2016

running no cat on my car, all else stock, was 156hp to the wheels. I do need to upgrade

Mike_D · May 11, 2016

millere5815 said:
running no cat on my car, all else stock, was 156hp to the wheels. I do need to upgrade

Have you tested exhaust back pressure, or are there other signs that you need to upgrade at your power level?

52172 · May 11, 2016

Im running 160hp through stock exhaust but gutted cat and mufflerectomy

millere5815 · May 11, 2016

Mike_D said:
Have you tested exhaust back pressure, or are there other signs that you need to upgrade at your power level?

No signs i need to upgrade that I can tell. Once I get my PD150 intake and upgraded pancake pipe installed, the exhaust is the only upgrade I plan on doing.

Seatman · May 11, 2016

From what I've read on here it seems unless you're going fairly big power the only downside of the stock pipe is maybe heat, higher egt's.

millere5815 · May 12, 2016

Seatman said:
From what I've read on here it seems unless you're going fairly big power the only downside of the stock pipe is maybe heat, higher egt's.

Only thing I really want to change is a larger down pipe. Eventually.

Layerz · May 13, 2016

Stock muffler imo is awful for flow, I've cut mine up and welding in a new pipe. Can post/share pics but know there are others out there.

I'm trying to keep the stock looking appearance, but have taken an S3 pipe and already has a mid silencer delete. My Cat is long gone too.
I've ground back and opened up the back box/muffler and taken out the collector and will weld onto/clamp the existing pipe and then weld and close it all back up.

turbovan+tdi · Jun 19, 2016

Layerz said:
Stock muffler imo is awful for flow, I've cut mine up and welding in a new pipe. Can post/share pics but know there are others out there.

I'm trying to keep the stock looking appearance, but have taken an S3 pipe and already has a mid silencer delete. My Cat is long gone too.
I've ground back and opened up the back box/muffler and taken out the collector and will weld onto/clamp the existing pipe and then weld and close it all back up.

Late to the party but agree'd. My 00 Sedan, has 205 nozzles, cat delete but stock dp, Colt stag 2 cam, 1.5 Malone tune, and ran the stock muffler for at least 6-8 months, then bought an Ebay 3" kit for the 1.8T and immediate difference on power and throttle, gained a solid 1 mpg. The wife commented on the difference so you know it made a difference.

Mike_D · Jun 20, 2016

Which ebay exhaust did you get?

turbovan+tdi · Jun 20, 2016

Mike_D said:
Which ebay exhaust did you get?

This one. I got this one first, just made a stock exhaust to 3" adapter and it was a good pic, fit like crap but I fixed that with some time. Sounded mean, had a nice bark to it. With a turn down, it was loud inside, straight out the back, no drone inside. I bought another kit as this one was out of stock, fit great but didn't sound as good.

http://www.ebay.com/itm/361202727693?_trksid=p2060353.m1438.l2649&ssPageName=STRK:MEBIDX:IT

Mike_D · Jun 21, 2016

Thanks for sending the link. If you wouldn't mind, could you send the link for the exhaust that fit well?

turbovan+tdi · Jun 22, 2016

Mike_D said:
Thanks for sending the link. If you wouldn't mind, could you send the link for the exhaust that fit well?

Can't find it.

How much power will stock ALH exhaust support?

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