Flowmaster / H Pipe / CA Smog laws
Thread Starter
Instructor
Joined: Jul 2008
Posts: 154
Likes: 0
From: CA
Flowmaster / H Pipe / CA Smog laws
Hello,
So far everything on my 1978 Pace vette is Stock! All I've been doing is restoring it.
I think its time for just one mod, and I'm thinking of replacing the Stock Y pipe to an H Pipe, and the mufflers switched out to Super 40's Flowmaster.
My concern is smog test. I live in California and I remember reading about that anything under 1975 does not require a smog test. and anything above does.
Would an H-Pipe / Flow 40's past smog test? and also what would I need to actually convert my Y Pipe to an H Pipe.
H Pipe
Cat conv
brackets
Flow 40's
OR
if anything would there be a noticeable sound difference if I were to keep the Y pipe and just change the mufflers to flow 40's ?
So far everything on my 1978 Pace vette is Stock! All I've been doing is restoring it.
I think its time for just one mod, and I'm thinking of replacing the Stock Y pipe to an H Pipe, and the mufflers switched out to Super 40's Flowmaster.
My concern is smog test. I live in California and I remember reading about that anything under 1975 does not require a smog test. and anything above does.
Would an H-Pipe / Flow 40's past smog test? and also what would I need to actually convert my Y Pipe to an H Pipe.
H Pipe
Cat conv
brackets
Flow 40's
OR
if anything would there be a noticeable sound difference if I were to keep the Y pipe and just change the mufflers to flow 40's ?
Burning Brakes
Joined: Feb 2003
Posts: 1,128
Likes: 4
From: Upland Ca
It may pass the sniffer test but will not pass a visual. I would buy the parts, swap out after the next smog (if not to far away) and change back every two years for smog test. Only a couple of hour every two years for the swap.
Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
Hello,
So far everything on my 1978 Pace vette is Stock! All I've been doing is restoring it.
I think its time for just one mod, and I'm thinking of replacing the Stock Y pipe to an H Pipe, and the mufflers switched out to Super 40's Flowmaster.
My concern is smog test. I live in California and I remember reading about that anything under 1975 does not require a smog test. and anything above does.
Would an H-Pipe / Flow 40's past smog test? and also what would I need to actually convert my Y Pipe to an H Pipe.
H Pipe
Cat conv
brackets
Flow 40's
OR
if anything would there be a noticeable sound difference if I were to keep the Y pipe and just change the mufflers to flow 40's ?
So far everything on my 1978 Pace vette is Stock! All I've been doing is restoring it.
I think its time for just one mod, and I'm thinking of replacing the Stock Y pipe to an H Pipe, and the mufflers switched out to Super 40's Flowmaster.
My concern is smog test. I live in California and I remember reading about that anything under 1975 does not require a smog test. and anything above does.
Would an H-Pipe / Flow 40's past smog test? and also what would I need to actually convert my Y Pipe to an H Pipe.
H Pipe
Cat conv
brackets
Flow 40's
OR
if anything would there be a noticeable sound difference if I were to keep the Y pipe and just change the mufflers to flow 40's ?
What can change is for example, you can increase your y-pipe to 2 1/2" reducing to a single 3" pipe, then run a new 3" monolythic hi-flow cat, they y back out to whichever size you prefer and mufflers you prefer.
An h-pipe before a single cat is a waste.
Legally you cannot run dual cats either.
All of this depends on the zip cosde within california, as there are some zip code where testing is not as stringent, or non existant all-together.
Yes there will be a noticable sound diff between factory and flowmaster mufflers, more so if you run a hi-flow cat.
Drifting
Joined: Aug 2007
Posts: 1,838
Likes: 13
From: Kingman AZ
This is exactlly what I was told when I started to plan for a better exhaust. Only one cat after a single y pipe. As stated , from the cat back are fair game and completely legal. Therfore the only legal way to make it work is a bigger Y pipe and hi flow cat with Flowmasters or your preference.
Last edited by rayluka; Jan 3, 2009 at 02:37 AM.
Burning Brakes
Joined: Aug 2006
Posts: 1,155
Likes: 0
From: San Diego California
I dont know how you can do a H pipe before a single cat. in california the ONLY legal configuration is the y-pipe to a single cat.. after the cat you can do whatever you want...Flowmaswters, striaght pipes.. doesnt matter..before the Catalitic convertor must remain at least the factory configuration.
What can change is for example, you can increase your y-pipe to 2 1/2" reducing to a single 3" pipe, then run a new 3" monolythic hi-flow cat, they y back out to whichever size you prefer and mufflers you prefer.
An h-pipe before a single cat is a waste.
Legally you cannot run dual cats either.
All of this depends on the zip cosde within california, as there are some zip code where testing is not as stringent, or non existant all-together.
Yes there will be a noticable sound diff between factory and flowmaster mufflers, more so if you run a hi-flow cat.
What can change is for example, you can increase your y-pipe to 2 1/2" reducing to a single 3" pipe, then run a new 3" monolythic hi-flow cat, they y back out to whichever size you prefer and mufflers you prefer.
An h-pipe before a single cat is a waste.
Legally you cannot run dual cats either.
All of this depends on the zip cosde within california, as there are some zip code where testing is not as stringent, or non existant all-together.
Yes there will be a noticable sound diff between factory and flowmaster mufflers, more so if you run a hi-flow cat.
