so i just got my cat back and downpipe. How much hp increase should i expect before a tune? Do I really need a tune?

 

Yes, you always need a tune.

 

I don't think its anything significant unless you get anything else done

 

does the car run lean or rich without a tune and my mods?

 

It'll still be running rich, but a tune will get you gains and lean it out. It'll also reduce knock as even from the factory you'll get knock. Just buy a Tactrix cable and contact either Mellon or Jestr.

 

You will be hitting different load cells In your map that have less timing and more fuel that could potentially make you lose some grunt.

Your spool will still be quicker, and the car will be louder, but dont let that fool you. The car should be safe AFR wise, but you will maximize your power (and ease your mind) if you get tuned.

Good luck man

 

this is my dyno from Friday. Not a before and after dyno of the TBE, but a dyno of TBE only, then TBE with a tune:

https://www.evolutionm.net/forums/sh...highlight=dyno

As you can see, it's worth getting tuned. No you don't NEED a tune, but you will not see the maximum gains from your mods until you get one, and that's the main purpose of the exhaust in the first place.

 

thanks for the referral

 

yes, you need to get a tune because now you're moving more air through the engine than before and hitting some load columns in the timing map with negative values.

If you haven't already, pick up a manual boost controller to compliment the new exhaust system and a k&n drop in air filter.

then get it tuned, most of my customers pick up 30-50awhp.