SoCA04V

I am doing my cam swap this weekend, and have an appointment scheduled for Wednesday of next week to have it tuned (Ryne at CMS). All of the parts will be here on time, except for the high flow cats. This would be a non issue, but I am on a time crunch and taking the car to Vegas Thursday after getting it tuned. My question is....will adding the high flow cats require another tune, or is the change not significant to worry about it?

Thanks in advance

SkullV

iTrader: (11)

You will need another tune to take advantage of the cats. Also make sure they turn off the rear o2 sensors in the initial tune or you will have a CEL until you get retuned.

BlackSVT03

iTrader: (1)

I didn't have any problems with my car. I installed the cam and got it tuned then installed the high flow mids. I took it to CMS with Pat and Ryne threw it on the dyno, but after running it a couple times he opted out of adjusting the tune because it was running perfectly with the mids.

itsslow98

iTrader: (18)

So I take it you dont have headers? I wouldnt worry too much, you might sacrifice a couple hp but nothing worth the price of a retune. Id just wait until you do a FAST or something else that justifies the tune.

SoCA04V

Thanks guys, my tuner said the same thing...he said he will turn off the rear 02's in preperation for the high flows, but said they wouldn't change the tune much.

shadyLS6

nooob question.. when i installed my headers with cats i connected the rear O2s but when i went for a tune my tunner insisted on turning them off.. if they are there why not use them wouldn't just improve the driveabilty of the car??

my thinking is more data = a more precise burn.

jasonk

iTrader: (29)

as far as I know the rear O2 sensors just validate that your catalytic convertors are working as advertised, they will not do anything to hurt fuel economy, that is determined by your upper O2 sensors working

itsslow98

iTrader: (18)

Once you are full throttle the car runs open loop anyways which doesnt utilize the rear o2s anyways.