Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

Rockers installed, computer learning issue? (PROBLEM SOLVED)

Thread Tools
 
Search this Thread
 
Old 06-25-2006, 09:17 PM
  #11  
Senior Member
True Car Nut
 
fantastic88's Avatar
 
Join Date: Jan 2004
Location: Lakeville, MN
Posts: 4,328
Likes: 0
Received 1 Like on 1 Post
fantastic88 is on a distinguished road
Default

I got LUCKY not having valve float, even with modified stock rockers because of my mileage. But with rollars its almost guarenteed even with a newer low mileage engine. Then again I do have stock shift points. When I get a DHP with 6K shifts, that may tell another story. Hopefully not though *knocks on wood*
Old 06-25-2006, 11:45 PM
  #12  
Senior Member
Posts like a Camaro
Thread Starter
 
chadow427's Avatar
 
Join Date: Jun 2005
Posts: 1,108
Likes: 0
Received 1 Like on 1 Post
chadow427 is on a distinguished road
Default

Just got back from another spin, I've put about 130 miles on it since the swap, the high end bog has gotten a little better, but not much. I'll just put the springs in and that should solve it.....here goes another rocker swap....if anybody needs help I've gotten it down to a couple hours...
Old 06-27-2006, 01:42 AM
  #13  
Senior Member
Posts like a Camaro
 
MACDRIVE's Avatar
 
Join Date: Dec 2005
Location: Clovis, CA
Posts: 851
Likes: 0
Received 0 Likes on 0 Posts
MACDRIVE is on a distinguished road
Default

What'* the ratio of your new rockers? :o
Old 06-27-2006, 04:28 PM
  #14  
Senior Member
Posts like a Camaro
Thread Starter
 
chadow427's Avatar
 
Join Date: Jun 2005
Posts: 1,108
Likes: 0
Received 1 Like on 1 Post
chadow427 is on a distinguished road
Default

1.9'*...
Old 06-27-2006, 06:06 PM
  #15  
Junior Member
Posts like a Ricer Type-R
 
willwren's Avatar
 
Join Date: Aug 2002
Posts: 11
Likes: 0
Received 4 Likes on 4 Posts
willwren is on a distinguished road
Default

You've done it three times now? Twice at my house, once at yours? Going for #4?

Good thing you bought that spring compressor. Now you need to get that air chuck/spark plug adapter rigged up.
Old 06-27-2006, 08:12 PM
  #16  
Senior Member
Posts like a Corvette
 
Foghorn's Avatar
 
Join Date: Jan 2004
Location: Montréal, QC
Posts: 1,374
Likes: 0
Received 0 Likes on 0 Posts
Foghorn is on a distinguished road
Default

Have you scanned again now you've put more miles on it? Can you post a scan so we can look at it?

You mentioned 14* KR in your first post, that can certainly make the car feel very flat and powerless. The KR you're getting is likely the result of the increased airflow seen by the MAF now you have higher ratio rockers. It'* unlikely your Long Term Fuel Trims (LTFT) are locking in close to zero when in Power Enrichment (PE) mode. The result is lean fuel mixtures, detonation and then Knock Retard (KR).

I've seen lots of SII L6s with rockers do fine on stock springs. I don't think that'* where your trouble lies. Do some more scanning to see your engine status...14* of timing retard by way of KR will kill your performance altogether. You might be walking into further problems.

Scan, scan, scan...it'* the only way to know what'* going on.

Cheers,
Old 06-27-2006, 10:22 PM
  #17  
Senior Member
True Car Nut
 
PontiacDad's Avatar
 
Join Date: Jun 2003
Location: Purgatory
Posts: 6,313
Likes: 0
Received 0 Likes on 0 Posts
PontiacDad is on a distinguished road
Default

I agree with foghorn, the springs are not causing 14* of kr.
There is something else going on, what kind of scanner do you have?
Old 06-27-2006, 11:29 PM
  #18  
Junior Member
Posts like a Ricer Type-R
 
willwren's Avatar
 
Join Date: Aug 2002
Posts: 11
Likes: 0
Received 4 Likes on 4 Posts
willwren is on a distinguished road
Default

A lean mixture (if not too severe) may be resolved with an adjustable FPR.

FALSE KR may be an issue if there'* excessive valvetrain noise. Does it sound louder? Clickety clackity?
Old 06-28-2006, 12:38 AM
  #19  
Junior Member
 
2000SilverBullet's Avatar
 
Join Date: Jun 2002
Posts: 0
Likes: 0
Received 0 Likes on 0 Posts
2000SilverBullet is on a distinguished road
Default

The slight ticking will not set off false knock.

If anything the lower pressure drop caused by opening the valves will lower the boost pressure and should reduce heating effect thus improving knock resistance.

I only had this limiter feeling type problem when I actually increased air flow by going to a smaller pulley.
When I swapped to the rockers I did not have this problem but then I did also do the springs and increased the fuel flow using the pressure regulator. :?
Old 06-28-2006, 04:00 AM
  #20  
Senior Member
Posts like a Camaro
Thread Starter
 
chadow427's Avatar
 
Join Date: Jun 2005
Posts: 1,108
Likes: 0
Received 1 Like on 1 Post
chadow427 is on a distinguished road
Default

It has reduced in severity, but still feels like its tapping the rev limiter at about 5700. I don't have an actual scanner, just an aeroforce interceptor gauge.

-Foghorn "You mentioned 14* KR in your first post, that can certainly make the car feel very flat and powerless. The KR you're getting is likely the result of the increased airflow seen by the MAF now you have higher ratio rockers. It'* unlikely your Long Term Fuel Trims (LTFT) are locking in close to zero when in Power Enrichment (PE) mode. The result is lean fuel mixtures, detonation and then Knock Retard (KR)."

So does that mean the computer needs more time at WOT to re-learn how much fuel is needed? I can do that. That was my initial impression, but then I thought it was springs.....now I don't know. Do the rockers increase the airflow enough that the computer would need a decent amount of time to relearn the fueling?


Quick Reply: Rockers installed, computer learning issue? (PROBLEM SOLVED)



All times are GMT -4. The time now is 02:57 PM.