If I install a complete Perrin exhaust with a Perrin Hi flow cat (not just a catback) do I need a tune? Otherwise it is a stock 2005 Lancer Evolution VIII (with a IX BOV) andI will not be making any other mods or adding an intake, boost controller, etc. I don't want to run much more boost than stock. Maybe a couple psi, whatever a stock car can reliable hold.


I am told anytime I replace the catalytic converter with an aftermarket I MUST tune it. Onlycatback systems don't require a tune, but full aftermarket exhaust must betuned....true? Why? Will it not run fine and/or not throw codes with a full exhaust/cat change?

 

You should be fine with an HFC in there. But a tune really is worth it. The car will run better and smoother than stock, with a lot more power.

 

When I bought my Evo it had a fmic and bov on an otherwise stock car. I added a megan downpipe, test pipe, and a buschur catback. Untuned it ran fine, I got the o2 code but did the defouler mod and haven't had a problem since. Would it run better with tune of coarse, but it runs fine without

 

You have to keep in mind when stating that you or someone you know has done something and the car ran fine or ran great that a car can be running dangerously lean and be running great at the same time.

 

I understand that...I had a guy mess with the jetting on a jetski carb years ago, (2-stroke) the thing ran awesome...until it was at wide open throttle for about 10 seconds then the pistons seized up from being lean, which also meant lake of oil in a two stroke.


Any good tuners in Charleston WV?

 

You aren't far from me, I'm in Hagerstown MD. Theres House of Power in New Oxford PA, about an hour and fifteen minutes away, another fifteen minutes to York PA there's CBRD, and then about two and a half hours in Blairsville PA there's TPG Tuning. Also a little over an hour into Fairfax VA is Moore Automotive.

 

The stock tune is rich, and gets rich as boost gets turned up. Exhaust reduces back pressure, and ups boost a little bit (increasing airflow), and the car runs richer since the MAF sees the extra airflow. It's well known that a turbo back exhaust is fine on these cars without tune. My car was tuned on the stock exhaust with just an intake, and an MBC, installing the turbo back made it richer.

 

Hagerstown is 4.5 hours, Oxford PA is 6 hour drive for me. Too far. I spend all my time in along I-77 from Charleston WV to Canton OH

 

no.

 

Yea my bad, thought I saw one more letter in Charelston. I'm sure I'm not the only one that happens to

 

I live in Hurricane, WV by the way. Do you have a wideband to datalog with?

 

Why no when many others think yes?

 

No wideband, nothing but a stock VIII with a stock IX BOV.

 

I don't see anyone in this thread saying you need to.
Your car won't need a tune . It'll run better and make more power, but that wasn't your question.
You're good to go.

 

If you decide to get a tune and want to go somewhere I would go to TPG Tuning. They are in the Pittsburgh area.