Posted this in the engine mods section but figured I would post the link here too because some of you that don't wonder over there might find the post interesting.

https://www.evolutionm.net/forums/sh...d.php?t=329753

 

How much WGDC did you have to increase to get the boost back up to where it was before it dropped off again at 5500+? I think 2psi lost because of that is very interesting.

 

It always seemed like I had to run more WGDC on the hiflow cat cars, I just never had a direct comparison on the same car between the two like this.

Here are the WGDC tables:



Test pipe on the left, hiflow cat on the right

So about 7.5% more at peak boost and 16.5% more at 7k

 

Wow, at 5500 where you reported the drop off its already to 10% more and starting to lose power. That is very interesting that it makes that much different. I almost wonder if a bigger diesel cat would work better for flow or if the substrate is different because of the type of fuel and needs therein?

 

This was some uber $$$$ JDM apexi cat as well.

We have some 100 cell cats we are going to test out as well. The actual substrate part is more than half shorter than this 130cel so they might flow a bit better.

I have tuned a couple evos with the 100 cell cats and they seem to make pretty good power.

 

Razor, Check these guys out for cats. WRC approved.
http://www.hjs-motorsport.de/english/produkte_kat.php

 

Yea looks like a normal metal substrate. All the metal substrates are pretty much the same, the differences are how many cells (lower, the less restriction) and how long the actual substrate is.

 

Hey, does anyone know about Random Technology Cats?

http://www.randomtechnology.com/products.html

I'm thinking of getting one and adding it, since my car has no cat presently, and I don't really want to get in trouble.

 

I checked into this a few months ago. They only have one US distributor, who would have to special order them at a seriously insane piece-price.

The HJS cats are very nice, though. Notice there is a gradual diffuser section approaching the catalyst brick. Shame that few of the other cats on the market have figured out that this is a good practice.

 

I've been using one now for a couple years. Unfortunately I do not have any hard data that would compare/contrast test pipe or stock cat for that matter.

They do seem to be a good option for those who want a cat. mrfred has run the random tech in the past and now has a avalet 100 (or whatever the cell number is) cats.

 

Razorlab you get my vote for EVO consumer reports guy. You have put up some very informative posts of late.

 

Anyone know where to find a 100 cell cat? I can't find the member that was selling them.

Thanks for sharing your findings razorlab!

 

The HJS units are $550 to $650 a UNIT. I looked into them and Billy Boat in AZ is their distributor, and that price is just insane (if you ask me). I think they may use more expensive PGM coatings (Palladium, Platinum and Rhodium), but I think the ones we sell offer close to the catalyst efficiency for a much more reasonable price.

The Random Tech unit is a 300 cell cat. Ours is 100 cell (formerly atlvalet). I think ours will flow more

BTW, if you call up Random they wil want to charge you $240+ for their unit