Pennock's Fiero Forum
  Technical Discussion & Questions
  Factory cat volume

Post New Topic  Post A Reply
Email This Page to Someone! | Printable Version


next newest topic | next oldest topic
Factory cat volume by f85gtron
Started on: 08-04-2013 09:00 PM
Replies: 13 (208 views)
Last post by: f85gtron on 08-14-2013 09:15 PM
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-04-2013 09:00 PM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would like to know the volume of the factory 85 gt cat...i would like to gutt it out, or replace it with a resonator. The vibrant ultra quiet is about 400+ ci.. if no ci info, then what are the w/h/l measurements? I'm going for a deep blub, blub, blub, instead off the ga, ga, ga, ga... I want to keep it simple, nothing major. Noooooooooooooo droning and low audibles.

While I was doing a search, I found this article on a fiero graveyard. I can't find a fiero in a wrecking yard to save my (fiero's) life!
http://www.thetruthaboutcar...s-the-fiero-factory/
IP: Logged
PFF
System Bot
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-13-2013 06:05 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Bueller? Anyone?
IP: Logged
steve308
Member
Posts: 3617
From: Stafford VA
Registered: Jan 2008


Feedback score: (2)
Leave feedback





Total ratings: 51
Rate this member

Report this Post08-13-2013 06:18 AM Click Here to See the Profile for steve308Send a Private Message to steve308Edit/Delete MessageReply w/QuoteDirect Link to This Post
IP: Logged
Raydar
Member
Posts: 39000
From: Carrollton GA. Out in the... country.
Registered: Oct 1999


Feedback score:    (12)
Leave feedback





Total ratings: 455
Rate this member

Report this Post08-13-2013 06:28 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by steve308:

All you need -----

www.youtube.com/watch?v=ieJUP9O9RG8


OMG! That's freakin' hilarious!
IP: Logged
Raydar
Member
Posts: 39000
From: Carrollton GA. Out in the... country.
Registered: Oct 1999


Feedback score:    (12)
Leave feedback





Total ratings: 455
Rate this member

Report this Post08-13-2013 06:31 AM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post

Raydar

39000 posts
Member since Oct 1999
To the OP...
Sorry. Can't help with specifics, but lots of guys replace the cat with a glasspack of the same length.
When I had my V6, I replaced the cat with a test pipe, and ran an Ocelot system. Sounded great!
IP: Logged
lateFormula
Member
Posts: 992
From: Detroit Rock City
Registered: Jul 2002


Feedback score: (2)
Leave feedback

Rate this member

Report this Post08-13-2013 11:15 AM Click Here to See the Profile for lateFormulaSend a Private Message to lateFormulaEdit/Delete MessageReply w/QuoteDirect Link to This Post
My 2ยข...

I replaced my converter and downpipe with a straight pipe that I made. The rest of the exhaust was stock. The straight pipe made the exhaust sound a bit louder; not a major difference but it was louder. But after a few years with the straight pipe I could no longer stand the stench of the non catalyzed exhaust. So I made another intermediate pipe with a Magnaflow 53004 converter. This new converter had almost no impact on the sound of the exhaust (idle, cruise, or WOT) or the performance of the car, but it did clean up the exhaust coming out of the tailpipes. Now I can start the Fiero in my garage and let it run for a couple minutes without stinking up the place.

This is it with the straight pipe (no converter): http://www.youtube.com/watch?v=Wrqy7rvkzd8
(Yes I know it was running pig rich due to a Hypertech chip in the ECU)

This is it with the new Magnaflow converter (and with the stock PROM chip): http://www.youtube.com/watch?v=f5LeZ8vjnxc
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post08-13-2013 11:33 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
If you need to replace the cat, put a new factory replacement on.

If you want a "deep glub glub glub" sound, swap in an SBC.

If you want a quiet exhaust, then use a stock design cat, and replace the muffler with an OE style that is quiet, and repair any leaks that may exist in the system.

A stock exhaust can actually be pretty quiet. I once looked at a Fiero about 10-11 years ago, that I didn't buy because it was too quiet.

Replacing any single point of the system is unlikely to result in what you want in terms of exhaust sound.
IP: Logged
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-14-2013 05:21 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok thanks for all the info! I have another related question: Can you change the tone of the exhaust note by increasing the volume (ci) of the system? For instance....if I throw a couple resonators on and increase the diameter cat-back?....or am I on the wrong trail? I like the idea of glass pack for the semi-quiet idle, but strong punch of wot action! I do most my driving at highway speed, so I don't want droning at all. Keep in mmind, I haven't even driven the car yet...i'm just anticipating....
IP: Logged
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-14-2013 05:29 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
The fart can innertube was hilarious! I can think of a few people to.....uh...imean..i can think of a few uses for that!

Dobey, what is an sbc?

[This message has been edited by f85gtron (edited 08-14-2013).]

IP: Logged
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-14-2013 06:04 AM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
[B]

This is it with the straight pipe (no converter): http://www.youtube.com/watch?v=Wrqy7rvkzd8
(Yes I know it was running pig rich due to a Hypertech chip in the ECU)

This is it with the new Magnaflow converter (and with the stock PROM chip): http://www.youtube.com/watch?v=f5LeZ8vjnxc


I appreciate the videos. I noticed a difference in sounds between the two...it seemed like the idle was more refined in the second video, while wot was similar. Thanks.
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post08-14-2013 09:22 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by f85gtron:

Ok thanks for all the info! I have another related question: Can you change the tone of the exhaust note by increasing the volume (ci) of the system? For instance....if I throw a couple resonators on and increase the diameter cat-back?....or am I on the wrong trail? I like the idea of glass pack for the semi-quiet idle, but strong punch of wot action! I do most my driving at highway speed, so I don't want droning at all. Keep in mmind, I haven't even driven the car yet...i'm just anticipating....


An SBC is a small block chevy. You're not going to get the V8 glub glub glub burble sound without a V8. Changing the diameter of the exhaust will change the tone, but also will affect performance. Too large an exhaust will give you a "deeper" tone, but the engine will also not perform as well, as the exhaust gases slow down when they expand to fill a larger area. Hollowing out a cat will actually result in worse performance, as the exhaust will expand too much in the cat. You're better off installing a new cat, than just hollowing the old one out. The Fiero's engine control system is also less efficient than modern systems, so there will be unburned fuel in the exhaust gases, especially if using a camshaft with overlap.
IP: Logged
PFF
System Bot
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-14-2013 02:54 PM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ok. Thanks. I'm not interested in motor swaps, or internal hd upgrades....sooooo I'll keep it straight and simple with a cat replacement and factory spec exhaust....for now. I AM, however, interested in REFINEMENTS that will update and create efficiency....
IP: Logged
dobey
Member
Posts: 11572
From:
Registered: Sep 2001


Feedback score: N/A
Leave feedback





Total ratings: 371
User Banned

Report this Post08-14-2013 03:00 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by f85gtron:

Ok. Thanks. I'm not interested in motor swaps, or internal hd upgrades....sooooo I'll keep it straight and simple with a cat replacement and factory spec exhaust....for now. I AM, however, interested in REFINEMENTS that will update and create efficiency....


Short of a drivetrain swap, you won't get much, if anything, out of little mods. Some larger mods may get some useful results, depend on what you're trying to get, and what you're working with. Granted a Gen I/II SBC won't get you any gain in efficiency, even if you did put one in.

IP: Logged
f85gtron
Member
Posts: 657
From: Augusta, Ga. USA
Registered: Jul 2013


Feedback score: (3)
Leave feedback

Rate this member

Report this Post08-14-2013 09:15 PM Click Here to See the Profile for f85gtronSend a Private Message to f85gtronEdit/Delete MessageReply w/QuoteDirect Link to This Post
Got it. The plan is to stay factory for now....maybe...
IP: Logged

next newest topic | next oldest topic

All times are ET (US)

Post New Topic  Post A Reply
Hop to:

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock