TPI Questions

[dzorde]

George,

6 deg is not bad on 87 octane, on leaded (96 octane) I can't run anymore
than 3 deg (allowing for small safety margin) without the engine starting to
ping (well, sound like a machine gun).  With the avgas (BP100) I can safely
run 6 deg.  Mind you I'm not using the standard ecu, so there's no knock
sensing or retard facility, hence it's critical that I leave a safety margin
as well.  However, I had come to the conclusion the pinging was mainly due
to the extremely high compression the engine has (between 220psi and 240psi
per cylinder).

In fact, I can run 10 deg static if I don't load the engine heavily, ie.
stay below 2500rpm in all gears.  Which is fine for city driving (less than
80kph), but you can't put your foot down at all.

Dan     dzorde at geocities.com.au

>Hi Dan, what were you able to set the timing too without getting excessive
>detonation? I could only getabout 6 degrees with my egr plugged.
>
>GMD
>
>
>At 06:10 AM 8/12/97 -0700, you wrote:
>>I'm lost, for a performance engine, do you want egr or not ?  When I built
>>my tpi 350, I pulled the egr valve and stuck a blanking plate over the hole
>>instead, oh, I also put the little metal plates in the manifold gaskets
>>where the egr is meant to breathe through.  Was this a mistake (I don't care
>>about economy, only power)? 
>>
>>Dan     dzorde at geocities.com
>>>> Thanks for the help.
>>>> 
>>>> This P/N thing is confusing.  I have the JTR book (and a bunch others)
>>>and
>>>> most say not to ground this pin.
>>>> If I remember correctly something to do with idle and deceleration. 
>>>Should
>>>> I be concerned????
>>>> I think a lot of this is tied to an automatic transmission, not manual. 
>>>Is
>>>> this true?
>>>
>>>I left mine open..sortta.  I'm using Aluminum Corvette heads that do not
>>>have the internal EGR passages in combination with a '86 VIN "F" TPI
>>>manifold.
>>>
>>>The EGR valve is still present and connected, but doesn't actually do
>>>anything since there isn't a supply of exhaust gas to the valve.
>>>
>>>Grounding the EGR feedback wire will set off the SES light (it simulates
>>>the EGR being stuck in the open position)
>>>
>>>Leaving it disconnected will also occasionally set off the SES light (there
>>>are a few cases where the ECM will command the EGR to actuate, then look to
>>>see what happened.)  Fortunately, temps down here are high enough that this
>>>doesn't happen often.  (been about 4 months since the last time the code
>>>went off) It will also clear itself within a few minutes of driving.
>>>
>>>Someday I'll have an EGR flange welded to one of the exhaust headers to
>>>supply external EGR.. but it's a low priority.
>>>
>>>Curt Martin (cmartin at america.com)
>>>Ormond Beach, FL
>>>http://www.america.com/~cmartin
>>>'87 350 TPI Camaro.. (used to be a 2.8L V6 :)
>>>
>>
>>
>>
>George M. Dailey
>gmd at tecinfo.com
>
>