exhaust.. to tune or not to tune?

[MarcusAurelius]

so, took the polo to a highly recommended exhaust fabricator today. i went in thinking "i know what i want"
i came out thinking "wtf"
supposedly there are 2 options:

i get a turbo-back exhaust made, but ill HAVE TO tune it, or get the ecu remapped cause itll throw up engine errors, or

i get a cat-back exhaust made, and i wont need to tune it.

the problem is, my cash flow has been plugged for a while and it looks like ill have to opt for the cat back for now then get the dp and cat done with a tune later on.

my question is, has anyone experimented with an exhaust with out a tune on their cars? (more specifically polo 6R 77tsi's)
and how did you go about it?

[Buller_Scott]

given how small the turbo is on the polo tsi, i would presume / project that any exhaust mods WITHOUT a tune would be a great way of giving the exhaust shop some money, with you receiving nothing noticeably different in return.

i doubt you'd even be able to dyno any differences between stock and aftermarket cat back.

to be honest, if you didnt want to get a tune just yet, but you're keen to do something with the exhaust to "add pace", the best thing you could do would be to chop your rear muffler off (called a mufflerectomy).... trust me when i say the cars sound no different between stock muffler on, and muffler chopped.

the weight saving alone will make your car faster than any aftermarket cat back w/ no tune combo.

what are your objectives in modifying the exhaust?

[MarcusAurelius]

a nice note would be nice, but if id like a performance add if anything.
so if anything, i should invest in a turbo back?
id chip it. buuuttt.. i still feel a bit iffy about chipping it. in the verry unfortunate event that the car, lets say, has problems *touch wood* i dont want my warranty voided..

[Bflat]

A 42DD o2 spacer from Greg Roles at Carformance solved my CEL issues when I got my Turbo-back downpipe plus cat. Give him a yell.

[Greg Roles]

Thanks Bflat, I was about to jump on and say the same thing. Any exhaust spacer for the cat converter O2 sensor will prevent the error light, which is ONLY a warning light anyway, and won't affect the running of the car.

I'd also suggest another exhaust shop if they didn't know this, it's pretty common knowledge!

[SMOK3Y]

the weight saving alone will make your car faster than any aftermarket cat back w/ no tune combo.

how much does the muffler weigh lol

[MarcusAurelius]

Would this also eliminate the potental for the car to run lean? Or cause harm?
Would there be a significant addition in power or just not quite worth it yet?

[GoLfMan]

all an larger diameter exhaust does is help gasses flow from the engine easier. You aren't going to get a HUGE hike in power, nor is your car going to explode. If anything it should run more efficiently due to the freer flowing nature.

Your car should run fine with a freer flowing exhaust. A tune only really will take advantage of the fact, and produce more power accordingly. Your MAF and O2 sensors etc should take care of proper fuelling for your car with the increased air flow

yeh a quality exhaust system is worth it, but do some research first as to which parts of the exhaust are the restrictive parts before you go throwing your cash at an exhaust place.

[Greg Roles]

If you are worried about warranty, let it be. If you want to be a bit more adventurous, and want the best effect from your exhaust mods, get a bigger than stock dump pipe ( turbo to cat ) and an O2 spacer. Allows the turbo to spool quicker, and a bit lower in the rev range on the stock ECU, provides a bit of a power increase. The cat back portion ( the last half ) only changes the sound, and any claims of power increases there are optimistic at best.

Some ECU tunes come with insurance to cover things the tune may cause, and just because you chip the car, doesn't mean your warranty on non involved items, such as the body and interior are voided. If you select a well known, more modest tune it;s doubtful you would have any problems. Pushing the envelope and getting stage 2 + style tunes trying for the last kw is where you can have things go "pop".

[Buller_Scott]

how much does the muffler weigh lol

sorry for the late reply mate.

i'd say stock would be around the 8kg mark, something like that.

i got mine chopped- sounded EXACTLY the same as stock as far as i can tell

[SMOK3Y]

thats cool mate would ya really notice the difference in performance (weight i mean?)

[team_v]

thats cool mate would ya really notice the difference in performance (weight i mean?)

I had my muffler cut off in the tig and it weighed 8kg.
It does sound louder than stock but i have Stage 2 so i was expecting it.

If you want power out of your cat-back system apprently you want to remove the resonator as it reduces the air flow through the system after the downpipe/cat.

The main gain will be from upgradinghte downpipe which will allow you to go to Stage 2 tune however you wil need to have the car re-mapped for this to work.

The weight difference was not so noticeable to me but i noticed the 12kg difference when i upgraded my wheels

[New2vw]

From experience from other turbo cars, any exhaust that reduces backpressure will get gains in response and slight power increase due to boost rise. The AFR might run leaner but it will be fine with factory tune as they tend to make it richer to avoid detonation by cooling the pistons and also for minor variation such as exhaust changes. The key is obviously whether the backpressure on the stock exhaust is high or not in the first place. Being new to VW, I am not sure but the Mitsubishis and Nissans Turbocharged vehicles that I have had in the past all behaved the same after exhaust change. with tuning as well obviously will bring more gains