High flow precat gains?
 

Hey guys,

I just did a mid muffler delete today on my TL.

I'm going to be getting a j-pipe next and then probably high flow cats.

Does anyone know what the gains are on high flow pre-cats and the cat after the j-pipe?

I spoke to the guy at the shop who did my muffler mod and he said I wouldn't gain much from high flow cats. I can't use the PCD's since it would fail emissions. I live in Allegheny county near pittsburgh.

I'm wondering if PCD's would pass emissions too since they would be barely visible anyway.

^you dont say what model your car is.

base cats have a cell count of 900.
type-s cats have a cell count of 600.
High flow cats have a cell count of 200-300
pcds are straight pipe so it has 0 cells.


from the base TL to high flow cats you'll be going from a 900 cell cat to a 300 cell.
pretty big improvement.

My bad its a base 08.

Sounds like that would be a huge difference. I will definitely be getting them then.

So for his 08, is he looking at like 25HP gain?

Seriously? If that's really what I'm looking at that would be awesome.

How did you come up with this number?

No way in hell....its more like 12hp:thumbsup:

^^^ well if that's about 12 hp per HFC, then there's your 25 whp! lol

I meant all toghether....

I know...I guess I should've used red letters......thought the "lol" was good enough...

I whipped it out of thin air, it gives him more hope than saying 1HP :tongue:

:werd:

Would that be a 1 cell instead of a 0 cell? Not to nitpick or anything :tongue:

Wow so if emission is not a factor and you have a type s there is no point to shell out close to $600 for high flow since the oem cats isnt that bad compare to the high flow. You will be better off to get pcd and wield a resonator to ur exhaust?

theres only a 3hp difference.....usually emissions is always a factor...depends on where u live I guess....^^^^^^I love my HF's

Where did u get that 3hp from?

I like the slight growl it gives at idle. I never experience the HFPC without the V2 at WOT, so I couldn't tell you about that. But I notice it on teh butt dyno,

Somebody get some dyno data into this thread

+1 for loving high flow cats

+2 here!

What kind of effects would a PCD have on the Type-S engine??

I know right, one thing i despise about all the forum vendors developing parts for the TL is lack of data and testing. Its just improved so buy it. (sarcasm)

From what I can deduct from Justin's post, a base TL will yield the biggest improvement while PCDs for a type-s will only be a small improvement considering the type-S already has higher flowing cats than the base. Although, the Honda manufacturers decided to add to production costs by making two different sets of cats for the base and type-s and there really isn't that great of a difference in cell count so maybe a little bit does help? You would be going from 600 cells to 1 cell. :tomato:

hfpc or not get ready for your exhaust to have some rasp

http://farm7.staticflickr.com/6139/5...986446c5_b.jpg

Justin 6MT - Rv6 V3 PCDs, RV6 v3 jpipe
Emmanuel 6MT - stock

Not true if your runnin a Atlp j-pipe.....rv6 j-pipe is causing your rasp on your exhaust...Heeltoe did a comparison on the 2 pipes.....I have no rasp at all....

Would just pcd's on my type s yield exhaust rasp?

A Type-S will still gain heavily from the full deletes. Going from 600 cell cats to straight pipes is still a vast improvement. In theory, it's the same flow improvement as going from the stock 900 cell base cats to the 200-300 cell HFC's.

High flow cats do not, in and of themselves. add rasp. I have none.

I read a tech article a while back that said when the type s came out 6hp was gained from going to 600 cell cats from 900 on the base. This makes sense because the 4g TL has the same engine as the type s but is rated at 280 since it has 900 cell cats vs 286 in the type s with 600 cell cats. Using that logic, I bet you would get 6hp for every 300 cell you lost on your primary cats. If I come across that article again, I will post the link.

My best guess is that on a base TL you will get:

6hp going to type s cats
12hp going to HFC
18hp going to PCD

Shameless plug: If you want the most gains possible, buy my V3 RV6 PCD for sale in the Black Market :thumbsup:

Thanks for chiming in wanted someone with experience to give their two cents.

The full deletes are a different story though. There are tons of variables with the different exhaust combos/resonator size, 3rd cat in place or deleted etc. Just know that with PCD's, in most situations, the probability of rasp is high. I don't have them though, so I can't speak from experience.

Nice thing about the HFC's is you don't have to worry about hacking into your exhaust and adding a huge resonator if the rasp gets annoying. My Excelerate cat back is the resonated version, but the resonator is so tiny I don't think it's doing much.

^just wanted to emphasize on the Variables part.
my set up does rasp, but I dont have any plans to quell the sound.
Unless, I were to get the rv6 exhaust.


also, our vee six is designed to sound ugly. lol
its just the way our motor sings!

Just an FYI, back when I had pre-cat deletes, and test pipe. My bumper turned yellow-blackish if I didnt stay on top of my weekly washes. Keep in mind I also have a white care. Im sure it doesn't show up on darker colors.

With windows down at a stop, could you distinctly smell the emissions?

Definitely. I'm not too concerned with emissions. It's not too hard to swap everything out or just swap the factory J-pipe back in. And the smell really isn't that bad. Ever go to a drag strip and smell all the uncatted cars there? Same thing.

It happens to dark colors too.

Taming the beast! PCD Rasp (videos posted) (click here)


http://pic80.picturetrail.com/VOL836.../391172795.jpg

http://pic80.picturetrail.com/VOL836.../391172793.jpg

AbyssPearlTL nailed it, but there isn't a smell with the windows up.

Thanks for clearing that up for me Inaccurate!

So it takes BOTH those to see about 15-20 gain on HP and TQ

You guys are right about on the money. I don't have any dynos, but with no changes other than the HFC's and using Dragtime's DA calc., I picked up a corrected 1.2 mph which equates to roughly 12 whp gained.

Damn, they turned your tips copper!

I usually take care of the copper color during a wash.
the bumper will need to be rubbed with rubbing alcohol and the tips can be taken care of with bar keepers friend