He must have had it backwards, Although you will get some additional kick with the more restricted cats, putting a less restrictive system on and also increasing the fueling wil give you some nice added power thoughout the range.

 

do you think i need to now re-reprogram the ecu? I just had the supercharger installed.

 

I have full Fabspeed Headers and exhaust with my evo supercharger and pulled a 389 rwhp on VF Engineering's Dyno.

 

did you make any changes to the fuel flow after the install?

 

drift: that's very impressive for a 3.4 liter. you didn't happen to dyno before and after the exhaust/headers did you? are those numbers corrected or uncorrected?

 

anybody else notice that EVO dropped the price for december by over a 1000 dollars for the SC kit? ouch, i should have waited

 

I'm alittle confused I would have guessed that if I installed headers special cats that the engine would need to be retuned, the airflow through the engine would be higher and boost pressure lower along with the A/F being off.

 

I would be livid! Deputy maybe you can speak with them to give you a discount on headers to lessen your pain. Sqweeky wheel gets the grease.

 

There should be no need to have the computer reprogrammed running a less restrictive exhaust. It has enough range to adjust the amount of fuel it needs. However, it would be a good idea to take a look at your fuel/air mixture at WOT to insure that you are not running too lean.

 

DOH! and instead of buying used i should have bought it new!

 

deputydog, the lower the cell count the less restriction and also less backpressure which can be detrimental to your overall power. You must have some backpressure and without it you may lose power. 300 cell cats give you a slight decrease in backpressure with a slight increase in flow to give more power. I am not an expert on this stuff, but if Mike at EVO claims that hiflo cats (100 cell) don't make a difference in power then it must be due to the loss of valueable backpressure which can rob you of hp. I guess the only way to find out is to dyno before and after exhuast install. I will probably have mine done soon and will post the results.

 

how many cells are the stock cats?

 

Mike actually came up to Toronto to do the install. He said the same to me "our cars need the back pressure or with increased flow you may risk losing power". He also said some kind of fuse or sensor kept blowing in a car that had the evo + highflow cat setup. I don't know if I should install the headers + cats from fabspeed now. What do you guys think?

 

yeah, the high flow cats will set off a check engine light in our SC cars. Todd said he is not sure if it's the cats or their programming.

i would go for just the headers and mufflers for now. rwdrift doesn't seem to have any problems with his setup.

do me a favor though. please dyno your car with the SC before you install the exhaust pieces. it would be really valuable to see exactly how much more power it produced and where the extra power came in at.

besides, it would be great to have a few more of us that have dyno'd their cars for comparisons' sake. wouldn't you like to know how much HP $11K bought you?

 

RWdrift: Did you do dyno runs on your car before and after the SC? You have the 3.4 liter right? Evo's site only shows 352 rwhp for your model? Your almost 40rwhp over that. Did you have a really strong 3.4 liter to begin with, or are you doing something different. Not to mention Evo's listed dyno numbers are way high as they used a mustang dyno (at least fo the 3.6 runs). You made almost the same rwhp as me (402ish) and I have a 3.6 with CG export mufflers (for whatever their worth).