PCM Diagnostics & Tuning HP Tuners | Holley | Diablo
Sponsored by:
Sponsored by:

If Catalytic deleted...

Thread Tools
 
Search this Thread
 
Old 11-30-2008, 02:12 PM
  #1  
12 Second Club
Thread Starter
iTrader: (7)
 
C_Rules's Avatar
 
Join Date: Oct 2005
Location: NYC
Posts: 1,666
Likes: 0
Received 0 Likes on 0 Posts

Default If Catalytic deleted...

Just a hypothetical question...When deleting your Catalytic converter should you max out all Catalytic overtemp tables? What does the CAT overtemp AFR table do?
Old 11-30-2008, 07:24 PM
  #2  
TECH Senior Member
iTrader: (7)
 
slow's Avatar
 
Join Date: Dec 2001
Location: Orlando
Posts: 6,151
Likes: 0
Received 1 Like on 1 Post

Default

Just turn off the COT fueling (if a scalar) (and disable the spark retard for catalytist lightoff tables if they exist)

If you cannot turn off COT, just raise the values.

Ryan
Old 11-30-2008, 09:33 PM
  #3  
12 Second Club
Thread Starter
iTrader: (7)
 
C_Rules's Avatar
 
Join Date: Oct 2005
Location: NYC
Posts: 1,666
Likes: 0
Received 0 Likes on 0 Posts

Default

I have an LT1 and use tunercats. I don't think there is an option to trun off COT fueling so I'll have to raise the values.

I'm still curious as to what the CAT overtemp AFR table does? Is that the AFR that is commanded when a certain temp is detected or is that the lowest afr that can be attained when a certain temp is detected?
Old 12-01-2008, 09:25 AM
  #4  
12 Second Club
Thread Starter
iTrader: (7)
 
C_Rules's Avatar
 
Join Date: Oct 2005
Location: NYC
Posts: 1,666
Likes: 0
Received 0 Likes on 0 Posts

Default

thanks. i dont believe tuner cats for the lt1 has a disable option but you can raise the overtemp values which in a sense would do the same thing.

if a vehicle does not have a cat how does the pcm monitor the temperature?
Old 12-01-2008, 11:28 AM
  #5  
Moderator
iTrader: (11)
 
jimmyblue's Avatar
 
Join Date: Mar 2002
Location: East Central Florida
Posts: 12,605
Likes: 0
Received 6 Likes on 6 Posts

Default

PCM does not monitor temp, it only makes a
prediction based on motor load, AFR and so on.

Setting the COT EQ value to the same as your
commanded PE is a pretty harmless way to go.
Old 12-01-2008, 12:17 PM
  #6  
12 Second Club
Thread Starter
iTrader: (7)
 
C_Rules's Avatar
 
Join Date: Oct 2005
Location: NYC
Posts: 1,666
Likes: 0
Received 0 Likes on 0 Posts

Default

Originally Posted by jimmyblue
PCM does not monitor temp, it only makes a
prediction based on motor load, AFR and so on.

Setting the COT EQ value to the same as your
commanded PE is a pretty harmless way to go.
That is a good idea too. Last time i was on the dyno the car was stuck at around 12.2 no matter what i was setting the PE at. I didn't know what was going on as i was trying to get it to 11.8 and it wasn't working. While I was working on my regular non WOT tune I came across the CAT Overtemp AFR constant and a light bulb went off in my head. I've tuned the car before and that did not happen to me before on the dyno. Anyway the car likes to be around 11.8 AFR naturally aspirated. Might be because of the overlap (224/236) of the cam. My graphs show the richer the a/f the more power to about 11.8.
Old 12-01-2008, 04:42 PM
  #7  
On The Tree
 
ssvolvo's Avatar
 
Join Date: Jul 2006
Location: great white northeast
Posts: 143
Likes: 0
Received 0 Likes on 0 Posts
Default

I have an 08 2500 HD. 6.0 LY6.

In the process of tuning it. ANY Power Enrichment is only done at WOT. The mid range open loop towing, hard driving but not wide open is ALL done by CAT protection.

Let me tell you it runs rich. 11.8-1.

Not really sure what GM is thinking but the stock VE table is stupid lean on top and pig rich on the bottom.

Looks like GM uses Cat protection for more than cat protection.

Stock truck, not even a K+N filter.

You should see the logs....The Arabs love me at the pump!
Old 12-01-2008, 05:08 PM
  #8  
TECH Resident
iTrader: (7)
 
BackinBlack02SS's Avatar
 
Join Date: Feb 2004
Posts: 879
Likes: 0
Received 0 Likes on 0 Posts

Default

I disabled it. Also set everything to 0, including the tables. If you do a search, there are some older posts with good info. Some guys were able to see some pretty nice dyno gains.




All times are GMT -5. The time now is 09:09 AM.