Hey guys, currently just installed some parts on my 2003 Evo 8...which include STM 02 housing/downpipe with the dump tube attachment so she screams, Buschur test pipe (defouler in place), Buschur Catback, and STM stock MAF Intake. No engine lights so far and car seems to be running great. Exhaust smells aren’t too much different it seems. Everything else is completely stock on the car as of now. Would you guys says it’s fine to continue like this without a tune and go WOT here and there? Or a tune is recommended. Mainly worried about the dump tube portion and boost creep/AFR’s being off. Was reading previous past post from like 2005-2011 and seems like a 50/50 chance to take. So I just wanted a straight-up more up to date answer. Also gonna be doing an STM intercooler with piping, e85, injectors, and an upgraded clutch as well in time though and that’s when I planned on doing a tune obviously due to the e85. Let me know what you guys think and thank you in advance.

 

Are you monitoring your AFRs and boost pressure?

 

Yes I am I have 3 gauges. Two of which consist of AFR & Boost of course.

 

Pull some logs if you have a Tactrix cable or at the very least pay attention to your wideband and boost pressure to make sure you're not over/under shooting your targets.

 

Let me rephrase that. I have all 3 but have not installed them as of yet. My local shop isn’t opening up till about another week or so due to COVID situation. So for now just running her as is.

 

Taking it to AG?

 

You could log the knock count with Evoscan and a Tactix cable. From what I've read, adding breathing mods will increase the knock count in the higher rpms on 91 octane so a tune is strongly recommended. You guys with 93 octane may get away without it, though.

 

Yes sir, I just might have to or another shop I have in mind that’s fine my previous gauges.

 

Yeah thats also what I’ve been told. We have 93 down here in Miami and that’s all I use so.

 

a screamer pipe is not going to affect your o2 readings much if at all

plus when the wastegate is open you will be in open loop which the o2 readings don't matter

the test pipe may change your VE but nothing too significant

plus the oem fuel maps are so rich. you don't have to worry

 

Ok perfect, thanks! I’ll be getting tuned hopefully soon anyways.

 

Fwiw, my car is 100% stock and I am on a stock map 93 oct and when data logging I was consistently getting 3+ knock counts from 5.8k - 7k rpm. The stock timing is pretty aggressive up there around 15-17 degrees so I wouldn't just "send it". I lowered my timing to 12-13 in that area to eliminate knock. From what I understand, the oem compensates for high timing with extra rich fuel map. Adding those mods will lean it out some, and I wouldn't recommend leaner + questionable timing imo.