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Re: Turbo V6 Tuniing continued



> In a message dated 5/4/00 2:10:41 AM Eastern Daylight Time,
> tystorm@email.msn.com writes:
>
> << While doing a WOT run, O2 volts were now steady
>  at 946 to 986 (was 1016 before on some areas, no lack of fuel now with 13
> to 15 psi) instead of falling off into the mid 800s with the stock
> injectors. I would also like to add to those who >>

> Jim Testa replied:
> Do TGP's like it that rich?? you might gain more bny leaning it out some.
> My GNB likes .790-.810.  Also, I like to go lean to the convertors stall
> point, helps spool immensly. And play with your timing maps around the
> convertor flash point, there are off the line gains to be had with that.
> Hmm..but then again, you didn't ask for opinions, so, I'll shut up.

Opinions away James, always glad to get-em ;-).  Some more info from me
would of helped but my emails are too long as it is ;-).  With the single
wire TGP GM sensor (new when the tuning efforts started), always showed
actual knocking at about 856 or less, showing 10 degrees knock retard at
low 800s.  From what I have seen with these engines and the cooling system
limits, the coolant temp rises pretty good after a WOT run on a hot day.
Even though the design of the cooling system for the TGP was greatly
improved, it still has it's limits and with over 100K miles, I expect the
radiator to have some mineral build up impeding peak heat transfer.  Add
that it runs aluminum heads and for my friends benefit as he likes to run
his car hard and long, I was shooting to run a cooler combustion temp by
running towards the rich side for now.  The spool up of this turbo is like
no other stock setup I have seen, this T25 (29 lb/min) is usually sized for
an engine from 2.0 to 2.4 liters, so this 3.1 without power breaking will
hit boost in nearly 1 second, and 8 psi in 1.3 sec and 10 psi in 1.8
seconds easy, frying the tires at 15 mph till about 28 to 31 mph (tire
speed, not vehicle).  Nothing like my friends TR or SyTys or Probe GT or
Dusters, but their turbos are larger relative to their displacement than the
setup for the TGP. I actually utilize the boost in the ECM to try to ramp up
the boost a little more gradually, to perform like traction control to keep
just at break point of traction.  This little V6 is a great stop light
warrior, pretty well for FWD but stock 245/50 tires also help.  Now I will
take your suggestion to the big fat 70 lb/min turbo on my Typhoon, though it
still has a 2800-3000 stall 911 converter, lag still happens there ;-).

Jeff M










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