nope... even a stock evo benifits from a 3" downpipe... the HKS was a poor choice.

 

No offense, but you shouldn't expect 3" number gains with a 2.5" system It's only .25" bigger than your stock setup.

 

yeah. 2.5 inches don't allow too much gains. If I were you, I would have gone with the RS-R, that way it has the cat-delete in it.

 

Any else actually have a 65mm dp and hi flow cat setup and if so what were your gains from it? I wasn't expecting the Dp to pick up that much whether it was 3" or not. I was expecting most of the power from the cat.

The thing is my car has days where it feels really strong and other days when it feels like it takes more throttle to do everything. It doesn't seem to be weather dependant either. I mean obviuosly it will feel stronger in 60 degree weather than in 90 degree weather. Some days it just doesn't feel as strong as it did the day before in similar conditions.

When the car is having a good day you can feel a difference from what it was before I had the cat & DP. It definitely feels like it picked up more than 6 hp on the good days. I think it was just having a down day when I dynoed it because, when I drove up there it didn't seem be as strong as it was the day before on the drive up there. Is there something funky with the mapping that it goes to a more conservative map for certain conditions besides detonation?

 

there's many circumstances that can cause a map to go conservative. Air temps, water temps, fuel, solar flare condition, etc can all be very problematic!

 

When I put the stock cat back with my UR HFC,3 inch megan downpipe and MBC. I was still 20 WHP more than my stock downpipe,stock cat and MBC. I bet that Helix HFC is more restrictive than UR HFC.

 

also remember that all hi-flow cats are not created equal.

A hi flow cat can only flow more air if it's less restrictive. Cats are rated in cells, the more the cells the more restrictive, the fewer cells, the less restrictive. Now the problem with fewer cells is that oftern the cat can't warm up enough to burn off all the dirty toxins. This will throw a code because it's the o2's report it as not working as it should.

In other words what I'm trying to say, is your hi flow cat may not be the same as your neighbors.

Edit: Just what the guy above me said.. sorry for the repost.

 

The Helix cat is a 200 cell metal catalyst and I have thrown the catalyzer efficiency too low code so, I think it is flowing fine. There are a lot of people on here who have made good power with them. I think for whatever reason it went to a conservative map on the way to the dyno from the in-laws. It was parked out side overnight and it was very cold. I don't know if that would somehow cause it to go to a conservative map but, I would think once it warmed up it would go back to the more aggressive mapping. I should have reset the ECM when I got to the dyno. I did it the day before on the way up there.

 

Which AWD dyno did you go too around Chalotte? Your HP figures seem low for replacing those two exhaunst components. Did your boost go up any when you added the DP and the HF cat?

Brian

 

I run the HK$ dp and Helix high-flow cat combo. I dyno'd 265awhp on Gruppe-S's mustang dyno a few weeks ago. I have an HK$ cat-back as well as a 10.5 hotside and a WORKS P2 flash.

 

I went to ride revolution in Bristol. That where the wifes family is at.

I picked up about a pound of boost with the cat and DP. It's good for about 21- 22 lbs of boost depending on the weather now.