Do I need a different tune after installing tp?

[Grk_A4]

My car is currently running the GIAC X-Flash. This week I will be installing a test pipe. I was wondering if my car will still perform the same or better with the same tune.

[Quattro]

i think you would need to add the test pipe file, so you dont get a check engine light...

[Entropy333]

+1 Thats what my local APR dealer told me

[Grk_A4]

yeah I am going to try to use the spark plug anti-fouler trick which plenty of people on vortex were successful with. So other than the check engine light I'm wondering if my car will still run smoothly and perform well without a different tune.

[supamannn99]

it acutally should run better because deleting the cat releases all that back pressure created by the cat, therefore giving you a better freeflowing exhaust outlet

[xX|05:A4|Xx]

i had a revo dealer tell me that most of the restrictive backpressure is from the mufflers. not sure if this is true. I actually got told this about 3 days ago when i had my car reflashed. but yea you will need a tp file in order not to trip a CEL

[Grk_A4]

it acutally should run better because deleting the cat releases all that back pressure created by the cat, therefore giving you a better freeflowing exhaust outlet

Thanks supamann. That's the reason I am installing the tp in order to relieve backpressure. I just wanted to make sure that my ecu could compensate for the increased air flow because I see many people with stage II tunes and wanted to make sure that I would be ok on just the GIAC X-flash.

[Auditude2.0T]

APR offers a TP file but i dnt think giac does.

[RedS-line]

i had a revo dealer tell me that most of the restrictive backpressure is from the mufflers. not sure if this is true. I actually got told this about 3 days ago when i had my car reflashed. but yea you will need a tp file in order not to trip a CEL

interesting. i heard the down pipe was the limiting factor in the exhaust system.

[vtracer20]

i believe both are but most gains come from an aftermarket downpipe rather than a muffler

[B7A4Sport]

Backpressure is mostly created by the smallest gauge pipe along the exhaust's path out of the engine. If the down-pipe is the thinnest, then it will create the most back-pressure; same goes for the cat or the muffler, but your flow is only as good as your thinnest pipe.

[bhvrdr]

It is possible you will see fuel cuts if you put the testpipe on. If that occurs, you'll want a fuel pump upgrade to go with it our you could go with the slightly detuned stage II files out there which would leave you with the same net power as before the testpipe. There arent many gains to be had on a maxed out chip program without fuel upgrades. I spent well over a grand on exhaust components such as catbacks, high flow cats, testpipes, to find that out. cheers! mike

[RedS-line]

what gets increased on the tuning after a test pipe is added? boost and timing or just boost? or is the boost just higher on stage II vs. stage I and the test pipe handles it better? anyone?

[Grk_A4]

Alright thanks Mike. I'll look out for the fuel cuts after I install it. Good information to know.

[bhvrdr]

what gets increased on the tuning after a test pipe is added? boost and timing or just boost? or is the boost just higher on stage II vs. stage I and the test pipe handles it better? anyone?

Most stage 1 files from the major tuners are now maxing out the fuel system. When a person adds a testpipe it may allow a bit more boost and then the person often experiences fuel cut in full load/no load transitions in upper gears around 3800-5000rpm IIRC. In order to combat this, tuners have developed a "stage II" software to tame down that added boost and allow the car to run again within the limits of the fuel system. You could see a bit more power at other rpm spots where the fuel system is not starved but in general once you are running a max performance stage 1 chip you are not seeing significant power increases until you have addressed the fuel system.

Here is an example...

Same car/same dyno...

Maxed out stage 1 chip program (210hp/240tq) versus chip and full 2.75" exhaust (208hp/250tq). If you look at the overlay the difference in hp and torque are negligible...



Now, on the same vehicle and same dyno we add a very high quality HJS 200cpsi high flow catalytic converter to the car that already now has the chip and full exhaust...

Dyno with chip and catback...



Dyno with chip, catback, and HJS 200cpsi high flow cat...



Yup, basically identical performance no matter what you add once the chip is maxed. I believe you can achieve some gains down low and way up top and those who have chips that are not maxed out such as a Revo chip that is set at conservative settings would probably see very significant gains adding an exhaust and testpipe, but yet you could just turn up the settings on such a chip and no longer be able to see those gains bc you'd be bumping the fuel limitations.

cheers! mike

[madrussian]

i dont think that spark plug trick that is on vortex works on our audi's.

i may be wrong, but i remember back in the b6 days that people were trying the same thing on 1.8t's unsuccessfully.

[RedS-line]

thanks for the info mike. do you think that adding s3 injectors simultaneously with an aftermarket fuel pump would help on power or no? seems like a lot of people are running the fuel pump but no one had the injectors....

[bhvrdr]

thanks for the info mike. do you think that adding s3 injectors simultaneously with an aftermarket fuel pump would help on power or no? seems like a lot of people are running the fuel pump but no one had the injectors....

It seems as though the tuners are saving the injectors for the slightly larger K04 turbo in the VW 2.0t FSI applications. When I logged injectors on our cars it looked a bit close but perhaps there is enough there.

http://www.mjbmotorsport.com/fsifuel.html

The true engineers employed by tuning companies know better then me so if they feel comfortable with the oem injectors for maxed out k03 setups it may be just fine. I'd say they are probably at their max capacity though in that configuration. As for upgrading the injectors yourself, I wouldnt recommend it without the proper tune. It would be interesting for someone to log out and dyno how the car responds to a slightly bigger injector and pump upgrade on a maxed out (tespipe and straight through exhaust) k03 setup. That would be fun data to see. Maybe take up a collection from us audiziners and try it out :)

cheers! mike

[CardNation]

I believe this thread just saved me some coin!

[RedS-line]

thanks again. i have read that link. its hard researching the fuel system but that is what i am most interested in since thats where i seem to be having the most problems. i might be oversimplifying, but i just assume that if the (tuned) car wants more fuel, and if the s3 injectors flow more fuel, then it would be beneficial.

[bhvrdr]

thanks again. i have read that link. its hard researching the fuel system but that is what i am most interested in since thats where i seem to be having the most problems. i might be oversimplifying, but i just assume that if the (tuned) car wants more fuel, and if the s3 injectors flow more fuel, then it would be beneficial.

The main problem people see with fuel cuts is the high pressure rail pump that is spun by the camshaft being able to ramp up fuel pressure fast enough when going from no load to full load situations. The aftermarket high pressure fuel pumps such as the ones from APR or the rebuild kits from Autotech are supposed to solve this problem in k03 applications.

cheers! Mike

[AudiWxGuy]

So is the new pump for AWE!