Downpipe worth it?

TDI_M

Active member
Joined
May 12, 2014
Location
Crestview, FL
TDI
2002 Jetta
My '02 ALH is completely stock and will probably never see major upgrades. Maybe injectors and a tune, but drive-ability and mileage are still priority. I'm looking at exhaust systems and wondering if a downpipe would be worth looking into, just a 2.25 or 2.5 inch. Thoughts? Thanks for your time.
 

50harleyrider

Top Post Dawg
Joined
Jun 16, 2007
Location
charleston,wv
TDI
2005 B5.5 TDI/geared BSM, BV43A turbo,stage 2 TDTUNING. 2005 5sp manual passat tdi stage 2 tdtuning,BSM delete. 2015 Passat TDI 6sp manual.
It's pretty much recognized that a larger diameter exhaust makes a positive difference on any diesel. If you plan on a bigger turbo, IC, intake,etc. probably should get one. Otherwise I wouldn't bother. You will make more noise with one too so factor that in. I've heard pros and cons about how much they help. Your turbo takes most of the energy out of the exhaust anyways. Oh, a big pipe sticking out the back looks cool too.
 
Last edited:

kd8cgo

Veteran Member
Joined
Aug 21, 2007
Location
Salem, Ohio USA
TDI
'02 Jetta
Downpipes and exhausts are a little pricey for the common options for the TDI vs. many other cars and trucks. Bigger is better on diesel to a point, yes - but bang for buck it is not on my list of 'first steps' especially on a stock turbo. Retaining the catalytic converter and going to larger pipes also adds cost, that depends on your State and priorities. Some people value the sound and look highly too, so it's a bit of a subjective mod.

For raw power for money, sticking a bigger turbo on plus your other listed mods - either low miles used or a new VNT-17 series has a similar cost to a downpipe and/or turbo back and will get you more power, even on a stock exhaust, for the money. You don't find 2.5" or 3" exhausts on 150-200HP production cars for a reason, it's not necessary or economical to attain those power levels vs. doing other stuff. I consider it more of stretching the last few % out of an already modded car, especially at TDI pipe prices.

You can take a TDI pretty far into the mod list without negatively impacting either mileage or drive-ability - and in fact a lot of people who can keep their foot out of it see mileage improvements after mods and tunes. For instance, there is no bolt on 17-series turbo that I would say negatively impacts your daily driving or reliability when driven in a sane manner.
 

TDI_M

Active member
Joined
May 12, 2014
Location
Crestview, FL
TDI
2002 Jetta
For raw power for money, sticking a bigger turbo on plus your other listed mods - either low miles used or a new VNT-17 series has a similar cost to a downpipe and/or turbo back and will get you more power, even on a stock exhaust, for the money. You don't find 2.5" or 3" exhausts on 150-200HP production cars for a reason, it's not necessary or economical to attain those power levels vs. doing other stuff. I consider it more of stretching the last few % out of an already modded car, especially at TDI pipe prices.
This is incredibly helpful, thank you so much. I'm not really interested in a different sound or look, I just enjoy driving so if something can be done to give a better experience without breaking the bank or negatively impacting mileage or reliability then I'm interested in exploring those options.
You'll definitely go faster with a big downpipe...
Well, at least I thought I wasn't interested in a different look. That's hawt mang. :D
 

duwem

Veteran Member
Joined
Apr 11, 2012
Location
Wi
TDI
2002 Golf GLS TDI 5 Speed
I would leave it stock in your case.

If you want some more flow or noise cut your muffler or cat off and straight pipe it, no point in going bigger DP if you still have all that stuff behind it.
 

deejaaa

Veteran Member
Joined
Apr 15, 2007
Location
Baytown, Texas
TDI
FOR SALE, 2002 Jetta GLS, 5 speed
............... Oh, a big pipe sticking out the back looks cool too.
score!
You'll definitely go faster with a big downpipe...
I would leave it stock in your case.

If you want some more flow or noise cut your muffler or cat off and straight pipe it, no point in going bigger DP if you still have all that stuff behind it.
i agree with this. i have straight pipe, not much louder. i get 60 mpg if i can keep it at 55 mph.
 

LNXGUY

Top Post Dawg
Joined
Jan 10, 2004
Location
Barrie, Ont, Canada
TDI
'05 Jetta TDI Wagon
My '02 ALH is completely stock and will probably never see major upgrades. Maybe injectors and a tune, but drive-ability and mileage are still priority. I'm looking at exhaust systems and wondering if a downpipe would be worth looking into, just a 2.25 or 2.5 inch. Thoughts? Thanks for your time.

Save your $$$.. The only thing I'd do to that car is maybe install a set of .205 nozzles for a nice little bump in hp/trq and fuel mileage.
 

Votblindub

Veteran Member
Joined
Dec 22, 2010
Location
NY
TDI
MK4 Jetta Wagon
It's more about if it's worth it to you. My sedan is automatic, it's not going have a race transmission, it's not going to be raced, but I still upgraded it a little. It felt a little anemic to me, so I did a little bit to get a little more out of it. Personally, I just wanted more power out of it, for what I need when driving in it. It needed a little help making that left turn quicker, or getting up to highway speeds. For a daily, it's okay, but I wanted a little more out of it. It wasn't about spending the dollars and cents(to a point), but making it get where I thought it should be. Obviously, your needs and finances are different from mine. I would say that, yes, it is worth it. It won't be a night and day difference, but since it's such a low hp motor, it's more palpable. The more open exhaust will let the turbo spool quicker and you can gain a little bit of power. The dollar to benefit is a ratio that you can determine.
 

dhangejr

Veteran Member
Joined
Mar 1, 2017
Location
PNW is my home
TDI
mk4 Jetta
Bump an old thread or start new? Ha

Thinking basically stock , tune and nozzles. Are EGT temps not a concern with these mods.
 
Last edited:

gibbswrecker

Member
Joined
Aug 6, 2017
Location
NC
TDI
04 jetta TDI
In most of any other diesel a bigger downpipe is used to get egt down while a tune and nozzles raise egt. I haven't personally seen what these cars egt are since i just bought my first tdi thursday so ive been trying to learn what one i have and such first. but i plan to do a larger exhaust tune injectors and pump mods if i have the ve one my old girl has 296k miles with an automatic. but my 06 f250 with a 6.0 runs near 1200* on the egt with half throttle almost with the mods i have to it just my .02
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
On the ALH, you can retain a stock exhaust from the turbo all the way to the tailpipe and still benefit power gains from different software and injector nozzles. The turbocharger itself is going to be the biggest limiting factor in the air coming in to and out of the engine.

Both my ALHs have such mods, and both have stock downpipes and catalysts in place. And they've both been like that for a VERY long time, run great, do not smoke, and get excellent fuel economy.
 

dhangejr

Veteran Member
Joined
Mar 1, 2017
Location
PNW is my home
TDI
mk4 Jetta
On the ALH, you can retain a stock exhaust from the turbo all the way to the tailpipe and still benefit power gains from different software and injector nozzles. The turbocharger itself is going to be the biggest limiting factor in the air coming in to and out of the engine.
Both my ALHs have such mods, and both have stock downpipes and catalysts in place. And they've both been like that for a VERY long time, run great, do not smoke, and get excellent fuel economy.

What nozzles ? Does it smoke on WOT?
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis, MO
TDI
There are just too many to list....
One has a very slight haze if you stand on it, the other has nothing visible.

They both have 11mm pumps, the one with no smoke is a MAF delete tune, and has good power down low but not much on the top end. The other has stock sofwtare, with a little more power above 3500.

I think the nozzles I have in the one are the one step up Bosch ones, same as what the 2.5L 5 cyl Transporters got. The other I have no idea.
 
Top