Charlie207
Full Access Member
I assure you that's not the case.
Black Bear Performance review after several months - engine, trans, AFM/DOD
- Thread starter LurkingLuke
- Start date
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Marky Dissod
Full Access Member
2. As an 'intermediate' IronHead LT1 tuner familiar with other powertrains that came with 4L60Es,
I know that 4L60E vehicles had SEPARATE 'Normal', 'Cruise', 'Performance' aka 'Tow/Haul', 'Manual', and 'Hot' shift tables.
EACH and EVERY one of them painted as conservatively as GM could get away with.
These tables (and their less obvious companion tables) are where the 'vehicle's personality are most obviously made to suit the driver -
IFF the tuner is either self-inclined, or the client encourages the tuner to do so.
'Cruise' should be the most conservative if it is available.
'Normal' should be conservative enough UNDER 31%-50% TPS that a secondary driver might never notice that the vehicle has been tuned,
but should come alive beyond a TPS percentage agreed upon by the tuner and the client.
*'Tow/Haul' should be tuned to protect the transmission and the engine equally, assuming it is towing/hauling 1500lb OVER its max tow rating.*
*'Performance' should be tuned to help the driver race / beat the ambulance to hospital, possibly at the cost of powertrain longevity at the client's insistent demand.*
*If the vehicle DOES NOT Tow/Haul, the Tow/Haul shift table can be used as a 'Performance' table, at the client's request.*
(My Tow/Haul behaves pretty much a Performance shift mode.)
'Manual' & 'Hot' shift tables should be written with an understanding that all the other shift tables were written to avoid using 'Manual' and 'Hot'.
These should be considered 'last resort', to be used only in the event of mechanical faults ... unless the client desires otherwise.
Everything above applies to 4L60E vehicles with pcms.
Vehicles with 6L80E 8L90E or 10L80 have even more shift tables and even more less obvious companion tables,
so schidt gets an order of magnitude more complex, but the gist should be more or less the same.
For now point is GM OE tunes so conservatively, that ANY tuner improvements are deeply appreciated;
but that does help tuners not go as far as they can, knowing full well that their clients will notice and appreciate whatever they'll do.
I know that 4L60E vehicles had SEPARATE 'Normal', 'Cruise', 'Performance' aka 'Tow/Haul', 'Manual', and 'Hot' shift tables.
EACH and EVERY one of them painted as conservatively as GM could get away with.
These tables (and their less obvious companion tables) are where the 'vehicle's personality are most obviously made to suit the driver -
IFF the tuner is either self-inclined, or the client encourages the tuner to do so.
'Cruise' should be the most conservative if it is available.
'Normal' should be conservative enough UNDER 31%-50% TPS that a secondary driver might never notice that the vehicle has been tuned,
but should come alive beyond a TPS percentage agreed upon by the tuner and the client.
*'Tow/Haul' should be tuned to protect the transmission and the engine equally, assuming it is towing/hauling 1500lb OVER its max tow rating.*
*'Performance' should be tuned to help the driver race / beat the ambulance to hospital, possibly at the cost of powertrain longevity at the client's insistent demand.*
*If the vehicle DOES NOT Tow/Haul, the Tow/Haul shift table can be used as a 'Performance' table, at the client's request.*
(My Tow/Haul behaves pretty much a Performance shift mode.)
'Manual' & 'Hot' shift tables should be written with an understanding that all the other shift tables were written to avoid using 'Manual' and 'Hot'.
These should be considered 'last resort', to be used only in the event of mechanical faults ... unless the client desires otherwise.
Everything above applies to 4L60E vehicles with pcms.
Vehicles with 6L80E 8L90E or 10L80 have even more shift tables and even more less obvious companion tables,
so schidt gets an order of magnitude more complex, but the gist should be more or less the same.
For now point is GM OE tunes so conservatively, that ANY tuner improvements are deeply appreciated;
but that does help tuners not go as far as they can, knowing full well that their clients will notice and appreciate whatever they'll do.
Granted / so stipulated.
Charlie207
Full Access Member
I just think this highlights one of the important shortcomings of "email tunes". There is basically no one nearby that can do a road tune or a dyno (rolling road) tune. So even though I log and log and log, the tuner isn't capable of experiencing the vehicle dynamics in person.
Marky Dissod
Full Access Member
Once, I was lucky enough to tune a Fleetwood V4P (the only LT1 sedans that came with 3.42, for a 7000lb Tow/Haul capacity rating).
Because I REALLY wanted him to be VERY happy with it, his pcm did 4 round trips to make Goldilocks come correct.
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