I'm confused so I figure I will ask. Ever since I became a member of the Evo forums I have read that Evo's run rich. While getting the driveline fluids changed the other day one of the guys at the shop said "I see you have the ETS intake and UR CB exhaust. You better be careful without a tune because the Evo runs very lean from the factory and those parts will make it leaner." Have i been misreadung what I have been reading on the forums?

Thanks

 

Do not run lean from the factory, but adding parts can/will lean it out a bit. Your exhaust is not a biggie, but the intake may be. Im not familiar with the ETS intake and if it requires a maf scaling calibration, someone else can chime in on that. Wideband wouldn't be a bad idea.

 

hell no they don't run lean stock

here is my post of my dyno run today :

https://www.evolutionm.net/forums/ev...riance-27.html

the only hiccup was the first one.. but the sniffer was almost coming out ( I think now that i think of it they said they had a bad contact on the sniffer)

 

True. Evo Xs typically don't run lean from the factory, though every car is a little different and can be somewhat affected by temperature, humidity, altitude, etc. An intake will certainly push the car further to the lean side.

There are plenty of posts where people have said their cars are fine, not lean, not too lean - probably ok, etc with an intake installed. My question is, why take the risk? It's a pretty expensive car and taking a bet that your car will be fine with an intake and no tune seems not a particularly smart risk to take. I might suggest just getting the car tuned and being gentle until you do.

 

the risk gets exponentially worst when you mod.

Its the nature of the beast , how you determine how to mod is entirely up to the owner.

Adding a intake will probably be safe to do without a tune unless you are changing the maf sensor housing ( like the AMS intake) , but again the risk must be taken by the owner.
By giving him data that cars are rich from factory , he can use that information to make a informed decision if he wants to add it without a retune.

Personally like you I wouldn't take a risk on an expensive car , and my method of modding is entirely on getting a re-tune.

I am doing mine by stages essentially

1) Catback + Intake = Retune right after install
2) Downpipe HFC + Intercooler and Harpipes = Retune right after install

Then I am done until I pay off the car

 

Cars come rich from factory like others have stated. Intake would likely even it out from what I've read. Not sure about the exhaust, but I'm sure youre fine. One of my friends ran an intake, intercooler, piping and exhaust w/o a tune for a few months. Everything seemed fine, but I myself wouldn't run that much without a tune

 

Yea I'm doing stages as well. Just more to each stage. Once I add the bigger IC, piping, down pipe and test pipe I will get a tune. Then save up for a larger turbo and all the supporting mods before tuning again. Thanks all for the responses. I did research prior to getting the intake and CB exhaust and feel its safe. I just found it odd that EVERY post I have ever read on the Evo states it runs rich but this shop says the opposite. And it's not some random shop. They have been racing and building race Evo's for over a decade from what I recall so it's not as though they are ignorant to the evo.

What afr is considered lean/rich and what has the 2012 evo shown in that area prior to tuning? I don't know a lot about tuning but I have learned a lot over the 8 months I have owned the Evo and have been coming here. Something like running rich or lean from the factory doesn't seem like the "what's the best oil,tires,brakes discussion that is open to opinion. AFR should be able to be shown EXACT right?

 

Most say the sweet spot for the afrs are anything between 11.2-11.5 on 91/93 octane respectively is a good area.

anything above that is lean and everything below its rich.

as you can see on my car on a stock tune ( see the link I gave you). my afrs are way below the chart.. its probably running like 8 to 1.. the first run was a fluke with a bad connection to the sensor.

 

This would of been me 100% to that guy at that shop...

 

I had my checked when it was stock and it was 10.2:1.
Safe on the OE tune:
--Any intake using an OE sized MAF (like K&N, AEM, Injen, ETS, etc)
--Upper and Lower IC pipe
--FMIC
--CBE

If you run a TP, you'll likely not have problems running lean, but it *could* cause you to start to overboost, and that will create problems...so it's really not suggested, but plenty of owners have done it without a problem. I choose to to install my TP and 3port the day I got tuned, because I didn't want to risk it.

 

Interesting. Looks like I can run my first stage mods w/o a tune. Thanks for the input