[Supras] Lexus AFM + 550cc + head removal advice

[berniek at technicaldevelop.com]

Brian:

    I've spoken with Reg a few times, but he is so busy it is difficult 
to get him on the phone.  I'm satisfied enough with the replies from 
list guys (thanks!) that I'll go forward with the 550's and Lex without 
further consideration. 

    One fly in the ointment is the time it may take to get a Texas 
titled car transferred to NJ registration.  The car will be here on the 
27th, and I'll be doing block lapping and the MHG the next week when my 
workplace is shut down.  I did buy a genuine Cometic HG rather than 
Titan.  I'd really like to put in the 550cc injectors and Lex while 
everything is apart, but will then need to pass NJ inspection.  With 
only a couple of days to transfer to NJ registration and sit in an 
inspection line, I don't think I'll make it if the transfer from Texas 
cannot be done the same day at the DMV here.  So, Murphy's law seems to 
rule, doing partially double work. 

    Never had a head off in the car before.  Advice, "gotchas", etc. 
would be appreciated.  What about the stock exhaust studs on the elbow?  
Do they customarily rust solid?

       Bernie

Walker, Brian (Rich. Dist) wrote:
>
> Bernie, have you tried discussing this with Reg? He's busy with many 
> other things these days but might be able to respond in his free time.
>
> FWIW, I've been running the 550/Lex combo for a few years along with 
> the RCTS screw and an AFPR. I also use a techtom ecu, which has an 
> advanced timing map (not sure if it's supposed to retard more under 
> boost than stock) I've never run the 550's without this program (was 
> set for 440s/stock AFM) and eg has no more rom boards so I can't get 
> an updated map. On an interesting note he advised that it was probably 
> the timing map needing the most work with the switch to 550's, not the 
> fuel map. Again, he does not have any rom boards left so I guess I 
> won't find out but that was his view. I'm hoping to get the speed 
> density setup going soon so I can monitor timing and get an idea of 
> how different the map is.
>
> Brian
>
> Date: Sun, 17 Jun 2007 02:33:34 -0400
> From: berniek at technicaldevelop.com
> Subject: [Supras] Lexus AFM + 550cc injector head scratcher
> To: Supras at supras.com
> Message-ID: <010101c7b0a9$6e02fe40$0f01a8c0 at Adminisrator>
> Content-Type: text/plain; charset=Windows-1252
>
> Hi list.
>
>     The original Reg information about the AFM-injector modification 
> painted a pretty simple picture.  Some list members I've exchanged 
> information with have done the mod without additional electronics by 
> setting the AFM bypass screw and pressure of a replacement FPR.
>
>     However, in reading some old tech postings, the point was made 
> that the ECU calculates spark retard values under boost by reading the 
> Karman vortex frequency.  Since it will be about 20% less for a given 
> air flow with the Lex-550cc modification, the ECU will not retard the 
> spark as much as with the standard setup.
>
>     Of course, the knock sensors will cause the spark to retard, but 
> should not be relied upon in the normal course of operation.  I'm 
> curious if anyone has considered this point or has had any problems in 
> running the Lex mod without electronic add-ons.
>
>     Thanks.
>
>         BernieK
>