Got 10 runs in last night at GLD. Not even 30 cars were there.
78 degrees. No wind.
Best run:........................Worst run:.............Best mph--114.24@12.6
12.32@114.01................12.99@113.07
60'--1.75..........................2.1
330'--5.1
1/8--7.9
mph--87.39
1000'--10.33

Got only 3 1.7 60'fts. 2step @ 6000rpms
Yeah I know...my grandmother can shift better.
All shifts were lifted. Full weight, 1/4 tank 93 oct. 52k stock clutch.

Running a test pipe and chucked my H/F cat. Boost went up to 23 from almost 22psi. after pipe swap. Left the boost since no timing was being pulled.
21 psi seen at 7000rpms in 4th. Never saw 23psi since rpms were never below 5500.
All night I was just looking at my traps compared to my H/F cat runs and I guess it did make a difference. 11's on that trap maybe? Hah...not with me driving .
I need 120mph to hit 11's.

Buddy of mine ( Evom member "51" was there with his 9. TB, mbc@23 I think, open air filter and a base flash. 12.3 @ 113. He cuts 1.6's 60ft's.
9's are sick.

 

Which HF-cat was this?

 

No surprise - HFCs are really not worth using. It's $200+ for less gains than a drop-in filter.

 

I agree to some extent, But I pass the sniffer and a visual inspection with a hi flow cat, drive my car every day and don't have to worry about the smell of not having a cat. Where have you seen the HP difference between a hi flow and stock cat to be "less gains than a drop-in filter".

 

Where have you seen them NOT be? You can pass the sniffer and visual inspection by spending no money on the stock cat. The gains from the HFC are negligible, and it's still a federal offense just like a test pipe. That's not a wise way to spend $200+, imo. Others may disagree...

What's the smell you speak of? I drive my car daily with a test pipe and don't smell anything. Do you sit in an enclosed garage with the car running a lot?

 

I gained 10whp and 21wtq on a Mustang Dyno w/o any additional tuning, by simply changing out the stock cat for a Perrin HiFlo cat. Well worth the $200 IMO, eh?

 

You can't even gain that much WTQ with a test pipe, so I don't believe you gained it with an HFC. The only way is if the boost raised due to the lessened backpressure and was not adjusted back down. People often overlook this very important factor...

 

Interesting point about the boost. To my knowledge the boost was not touched.
I'll see if I can locate the before and after graphs, but the #'s just from the Perrin cat:
Before - After
281whp- 290whp
277wtq- 298wtq

 

Most of HFC is better than stock cat. Stock cat is not bad but Even cheap UR HFC gave me obvious gain than stock cat.
However, test pipe is always the best and give you the full potential of you car.

And if you have more mods, effects of these changes are big.

 

Ultimate Racing.
Been on the car since 1100 miles.

It does have a diff. smell to it on stop lights, but tolerable.
I was tuned at 21 psi with the hf. Anything over that, I'd get a degree of timing pulled on the 3rd run during logging.
With the test pipe in place, I can run a little higher boost and not get any timing pulled. ( so far )
Turbocharged engines likes the least back pressure in the exhaust. Esp on high boost applications.
So test pipe is staying and hf cat is back in the box.
.