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Pettit Super Charger Owners

Old Mar 12, 2008 | 05:33 AM
  #1451  
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Originally Posted by MazdaManiac
I'm not sure if the vehicle that I just worked with had a screen or not.
Since the idle is so high on the Pettit application, the accuracy of the low-end flow isn't as important.
I'd suggest it, but getting the MAF tube out to a proper length is going to be more important.
Jeff, were you able to address the high idle?
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Old Mar 12, 2008 | 09:24 AM
  #1452  
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My understanding Lola is since the s.c places a load on the engine from idle upward--it requires a faster idle than oem. personnally i have always preferred an idle of around 1 k on this engine. it seems happier.
olddragger
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Old Mar 12, 2008 | 10:57 AM
  #1453  
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I must be lucky. My idle has always been stable and "rock solid" at 1100 rpm after the SC install, everytime, even after I reset the PCM (pull the room fuse). And I'm running a screen.
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Old Mar 12, 2008 | 12:14 PM
  #1454  
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Zen, the 1,100 rpm idle speed has always been smooth. The idea was whether ot not 1,100 was a desirable idle speed or not.
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Old Mar 12, 2008 | 12:27 PM
  #1455  
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As the S/C places more load on the engine, as does an A/C compressor or alternator, the speed of idle need not change. The trick is to automatically get more thottle opening to conteract the load, but not exceed it, so the target RPM remains the same.

Cheers,
Hymee.
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Old Mar 12, 2008 | 12:32 PM
  #1456  
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MM was thinking, last I knew, that the S/C may have been wreaking havoc on the MAF sensor as a result of a few issues. Any ideas, Hymee?
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Old Mar 12, 2008 | 12:40 PM
  #1457  
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Originally Posted by Charles R. Hill
MM was thinking, last I knew, that the S/C may have been wreaking havoc on the MAF sensor as a result of a few issues. Any ideas, Hymee?
In theory, at idle the S/C isn't "there" as the bypass valve is open. In practice the bypass is actually open. What this means is that the S/C is no putting any boost into the intake, or drawing in any more are than what the engine wants. So in this repsect, theory matches practice.

I assume what your getting at is the concept of "reversion" (i.e. the S/C creating pulses back up the MAF tube), which needs more study I guess, rather than postulation.

That said, the engine still has a net postive flow of air that is all being measured by the MAF...

Cheers,
Hymee.
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Old Mar 12, 2008 | 12:50 PM
  #1458  
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Yep, the reversion-pulse theory.
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Old Mar 12, 2008 | 12:54 PM
  #1459  
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You go, guys. I can't wait until you work the bugs out of this piece of crap
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Old Mar 12, 2008 | 12:55 PM
  #1460  
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Originally Posted by MazdaManiac
I'm not sure if the vehicle that I just worked with had a screen or not.
Since the idle is so high on the Pettit application, the accuracy of the low-end flow isn't as important.
I'd suggest it, but getting the MAF tube out to a proper length is going to be more important.
Could you find out, because i'm thinking it wouldn't be hard at all to glue the stock screen to the front of the new MAF housing?
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Old Mar 12, 2008 | 01:07 PM
  #1461  
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Yeah, it has to be kept up to 1100 because of the way the kit is designed.
If it had been done right, there wouldn't be a load at idle.
I can set the idle anywhere I want, but it seeks pretty heavily at anything under 1k.
The BPV flutters, too, which makes it even more difficult.
A clutch (like the OEMs) would have fixed this.

Last edited by MazdaManiac; Mar 12, 2008 at 01:10 PM.
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Old Mar 12, 2008 | 01:40 PM
  #1462  
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A couple of points (before people get their panties in a wad):

The cause of the bad idle is not totally clear to me, but it appears to be a combination of "chopping" from the blower, odd spring tension on the BPV, bad MAF housing design and load.
That said, at 1100 RPM, it is quite nice.
I don't know that I hate it. lol.
Honestly, the twin-screw makes some really musical noises and the power delivery is more than satisfactory.
From the beginning, my assault on the Pettit is not because it is an SC but because the engineering of the kit was so lax.
Fortunately, the issues are being met one by one and it will ultimately be an excellent system.
Its just too bad that the owners need to bear the brunt of this re-engineering effort.
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Old Mar 12, 2008 | 01:47 PM
  #1463  
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Originally Posted by MazdaManiac
A couple of points (before people get their panties in a wad):

The cause of the bad idle is not totally clear to me, but it appears to be a combination of "chopping" from the blower, odd spring tension on the BPV, bad MAF housing design and load.
That said, at 1100 RPM, it is quite nice.
I don't know that I hate it. lol.
Honestly, the twin-screw makes some really musical noises and the power delivery is more than satisfactory.
From the beginning, my assault on the Pettit is not because it is an SC but because the engineering of the kit was so lax.
Fortunately, the issues are being met one by one and it will ultimately be an excellent system.
Its just too bad that the owners need to bear the brunt of this re-engineering effort.
sounds like the first run's of the greddy kit. Just my thoughts haha.
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Old Mar 12, 2008 | 01:50 PM
  #1464  
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first run? greddy never fixed anything of substance even today. That's why we replace the fuel management, and better yet, replace the turbo. Then it's a damn fine kit.
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Old Mar 12, 2008 | 01:51 PM
  #1465  
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Yes, Varney. There is the engineering and then there is the politics. Rarely do they have much to do with one another.
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Old Mar 12, 2008 | 01:59 PM
  #1466  
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Think - Army Corps of Engineering.
Then think - New Orleans.
Then think - Katrina.

Politics and engineering mixed into the finest broth!
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Old Mar 12, 2008 | 02:03 PM
  #1467  
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Originally Posted by MazdaManiac
Think - Army Corps of Engineering.
Then think - New Orleans.
Then think - Katrina.

Politics and engineering mixed into the finest broth!
Think humans...
Think stupid idea to place a city...
Think nature...

Even after centuries and countless lives lost...humans still have not learned...

Stupidity trumps politics every time...

Carry on...
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Old Mar 12, 2008 | 02:07 PM
  #1468  
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Originally Posted by MazdaManiac
I'm not sure if the vehicle that I just worked with had a screen or not.
Since the idle is so high on the Pettit application, the accuracy of the low-end flow isn't as important.
I'd suggest it, but getting the MAF tube out to a proper length is going to be more important.
No it does not.
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Old Mar 12, 2008 | 02:15 PM
  #1469  
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Originally Posted by eviltwinkie
Think humans...
Think stupid idea to place a city...
Think nature...

Even after centuries and countless lives lost...humans still have not learned...

Stupidity trumps politics every time...

Carry on...
Oh yes and it's all your fault as you are supposed to watching the gene pool - FAIL
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Old Mar 12, 2008 | 02:18 PM
  #1470  
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Originally Posted by Phil's 8
Oh yes and it's all your fault as you are supposed to watching the gene pool - FAIL
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Old Mar 12, 2008 | 05:03 PM
  #1471  
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Originally Posted by MazdaManiac
Fortunately, the issues are being met one by one and it will ultimately be an excellent system.
Oh, Oh! Jeff is going softy on us again. WTF, can someone please get him back on track. Bastage, Shinka, OD, anyone...pleaseeeee.
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Old Mar 12, 2008 | 05:08 PM
  #1472  
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Originally Posted by marsredr100
Oh, Oh! Jeff is going softy on us again. WTF, can someone please get him back on track. Bastage, Shinka, OD, anyone...pleaseeeee.
Don't jump to conclusions, Juan.
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Old Mar 12, 2008 | 05:39 PM
  #1473  
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Originally Posted by marsredr100
Oh, Oh! Jeff is going softy on us again. WTF, can someone please get him back on track. Bastage, Shinka, OD, anyone...pleaseeeee.
OK... I'll start by saying...

Nah nevermind, not worth it.
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Old Mar 12, 2008 | 06:15 PM
  #1474  
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Anyone now who won the BP car, maybe a friend of a friend. Who ever did is one lucky basterd.
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Old Mar 12, 2008 | 06:42 PM
  #1475  
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I got inspired and started playing with the Electronic Throttle Control stuff a bit. I had the idle down to 950 and the ETC caught the rapid throttle off about 85% of the time after a hard pull but it would still stall from time to time.
I know, I know…. That is not good enough and I agree but it was a lot better. You can also let the clutch out now without touching the gas and it will drive away (like a proper ETC car should).
I'll keep at it when I find spare time and maybe I will get lucky.
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