Catalytic Converter: Suggestions - Page 2 - RX7Club.com - Mazda RX7 Forum

3rd Generation Specific (1993-2002) 1993-2002 Discussion including performance modifications and Technical Support Sections.

Catalytic Converter: Suggestions

Reply

 
 
 
Old 08-28-17, 10:00 AM
  #26  
Quietude of heart.
Thread Starter
iTrader: (6)
 
MK3Brent's Avatar
 
Join Date: Jul 2010
Location: North Carolina
Posts: 456
Thanked 9 Times in 7 Posts
Originally Posted by IRPerformance View Post
461 whp/372 tq with our ported and studded motor, S360 single turbo kit, Bonez high flow cat, and Racing Beat catback. These numbers would equate to about 530hp on a Dynojet factoring in the 15% difference commonly found. The cat is not the issue.
Definitely not the original direction intended for this thread, but I am more than happy to help with education.

Wouldn't it be logical to say that w/o the cat, the numbers you posted could only be improved?
It would be interesting to see two back to back runs w/ and w/o the cat to show no difference at all.
MK3Brent is offline  
Reply With Quote
Old 08-28-17, 10:02 AM
  #27  
Lives on the Forum

iTrader: (6)
 
7_rocket's Avatar
 
Join Date: Jul 2003
Location: Toronto
Posts: 7,066
Thanked 10 Times in 9 Posts
Does the Bonez not reduce/eliminate most of the smell? I was thinking about going with the Bonez this fall because my car stinks (midpipe)
7_rocket is online now  
Reply With Quote
Old 08-28-17, 10:35 AM
  #28  
Rotary Freak
iTrader: (12)
 
moehler's Avatar
 
Join Date: Mar 2003
Location: South Jersey
Posts: 2,237
Thanks: 0
Thanked 8 Times in 7 Posts
Originally Posted by MK3Brent View Post
Definitely not the original direction intended for this thread, but I am more than happy to help with education.

Wouldn't it be logical to say that w/o the cat, the numbers you posted could only be improved?
It would be interesting to see two back to back runs w/ and w/o the cat to show no difference at all.
I'm sure the cat reduces power over a midpipe. The point is that if want a cat (for smell, etc.) that you can still make good power with them.
moehler is offline  
Reply With Quote
Old 08-28-17, 10:36 AM
  #29  
Rotary Freak
iTrader: (12)
 
moehler's Avatar
 
Join Date: Mar 2003
Location: South Jersey
Posts: 2,237
Thanks: 0
Thanked 8 Times in 7 Posts
Originally Posted by 7_rocket View Post
Does the Bonez not reduce/eliminate most of the smell? I was thinking about going with the Bonez this fall because my car stinks (midpipe)
With an air pump, yes it eliminates 100% of the smell. W/o an air pump it eliminates most of the smell.
moehler is offline  
Reply With Quote
The Following User Says Thank You to moehler For This Useful Post:
7_rocket (08-28-17)
Old 08-28-17, 01:06 PM
  #30  
Sponsor
RX7Club Vendor
iTrader: (41)
 
IRPerformance's Avatar
 
Join Date: Apr 2003
Location: NJ
Posts: 10,844
Thanked 20 Times in 18 Posts
Originally Posted by MK3Brent View Post
Definitely not the original direction intended for this thread, but I am more than happy to help with education.

Wouldn't it be logical to say that w/o the cat, the numbers you posted could only be improved?
It would be interesting to see two back to back runs w/ and w/o the cat to show no difference at all.
We have seen gains up to 20 hp at this power level by replacing the high flow cat with a midpipe and installing a better flowing exhaust than the Racing Beat, which is on the restrictive side vs some of the other offerings on the market. My point is you can still make solid numbers with a high flow cat, unlike some who post ignorant comments that you can't or shouldn't run a cat above a certain power level with no factual data. Some people are willing to give up a few hp to remain compliant or avoid the smell of running catless. I'm actually going to dyno another car within the next few weeks with a similar setup to the one who's dyno sheet I posted, but with a Magnaflow midpipe and a different exhaust. I'll post the results when I get them.
IRPerformance is offline  
Reply With Quote
The Following 2 Users Say Thank You to IRPerformance For This Useful Post:
bajaman (08-29-17), MK3Brent (08-28-17)
Old 12-13-17, 10:06 AM
  #31  
Full Member
iTrader: (5)
 
Hi Im Simon's Avatar
 
Join Date: Oct 2004
Location: so cal
Posts: 152
Thanked 1 Time in 1 Post
Originally Posted by Topolino View Post
Recently went with a Vibrant Ultra High output cat (p/n 7830 from the link above) on my FD in conjunction with an EFR 7670 turbo. Have mostly used a Bonez high flow cat the last 10 yrs or so with Efini twins, and wanted to give the Vibrant unit a test run. Interestingly enough, we weren't able to boost higher than 10-11 psi on the new turbo setup. Not sure if the Vibrant cat is the primary restriction or not (but obviously no boost creep with it, either).

Seems to knock down the odors well-enough. Not sure if it can pass a legitimate emissions test, though.
Damn I thought the Vibrant cat would work well. I was looking into the Vibrant and HJS high flow cats. Anyone have any experience with HJS? The BMW and Porsche guys seem to love it and they are expensive, $600-1000 USD. I was mainly looking to get rid of the exhaust stink.

Universal catalysts - HJS Motorsport & Tuning
Hi Im Simon is offline  
Reply With Quote
Old 12-15-17, 07:12 AM
  #32  
Lives on the Forum
iTrader: (4)
 
David Hayes's Avatar
 
Join Date: Jun 2002
Location: FL
Posts: 6,081
Thanks: 0
Thanked 11 Times in 8 Posts
I may be the only 3 rotor guy to run a cat on his/her car. Wanted to get rid of the stink so tried a few units. Settled on the MBS 100 cell unit and have had it installed for around 3 years:

High Flow Catalytic Converters - Mandrel Bending Solutions

Holds up to the heat of the rotary and eliminates a good bit of the stink. The 200 cell would eliminate more of the smell but I was worried about the restriction. And yes, you can make good power using a high-flow cat. Here is my dyno at 20 PSI:



Made 716 WHP and 570 ft. lbs.
Attached Thumbnails Catalytic Converter: Suggestions-img_20171004_0002.jpg  
David Hayes is offline  
Reply With Quote
The Following 2 Users Say Thank You to David Hayes For This Useful Post:
cib24 (01-04-18), Natey (01-01-18)
Old 01-01-18, 02:25 PM
  #33  
Retired Moderator
iTrader: (204)
 
GoodfellaFD3S's Avatar
 
Join Date: Mar 2001
Location: FL-->NJ/NYC again!
Posts: 29,960
Thanked 95 Times in 84 Posts
David, do you have any pics of that converter installed on your setup? Assuming it's mounted pretty far downstream. The price sure as hell is right, and they seem to be nice and compact based on the pics on the site you linked to.

I may have to change my tune on this subject, once you stop learning and growing you may as well be six feet under, right?

Happy New Year all
GoodfellaFD3S is offline  
Reply With Quote
Old 01-01-18, 04:27 PM
  #34  
Lives on the Forum
iTrader: (4)
 
David Hayes's Avatar
 
Join Date: Jun 2002
Location: FL
Posts: 6,081
Thanks: 0
Thanked 11 Times in 8 Posts
Hey Rich. I don't seem to have a pic handy but will take one - once the car comes back from the body shop. A lady with a 1994 Buick Roadmaster station wagon backed into me a few weeks ago and it crunched the left side of my bumper.

As I recall, the converter is placed forward in the midpipe, not back, but I'd need to verify this as the work was done some time ago. Has held up well and cleans up most of the rotary stink. Zach at Addicted and I think there is little to no impact of the converter on WHP. If you were to use a higher cell count one (say 400 or higher) you'd definitely get a restriction so it's a matter of using a lower cell count and giving up some of its cleaning abilities.
David Hayes is offline  
Reply With Quote
Old 01-04-18, 06:06 AM
  #35  
Senior Member
 
Join Date: May 2015
Location: UK
Posts: 320
Thanked 7 Times in 6 Posts
People need to stop thinking that a cat is going to inhibit your ability to make power. High flow cats are not really that much of a restriction at all and like IR Performance says, at 450, 500, 600, whatever horsepower you aren't going to notice 10 or 20 hp. You probably wouldn't even notice that difference on a car with stock twins.

Manufacturers today have cars like the Corvette pushing 700+ horsepower and they have 2-4 cats. Set your exhaust up right and you will have plenty of flow and stay away from the headaches and poison to your lungs and the environment associated with running catless.
cib24 is offline  
Reply With Quote
The Following User Says Thank You to cib24 For This Useful Post:
NJ-JDM (01-04-18)
 
 
 


Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.