Questions about tuning an 8746
07-27-2005, 07:47 PM
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Car: 1991 Firebird
Engine: 350,Dart Heads,Weiand In,Roller Cam
Transmission: 2400-Stall, 700R4 w/ Kit
Axle/Gears: 4th Gen 3.42 disc (I wish)
Questions about tuning an 8746 w/ TPRT
TunerPro RT and an 8746
Pumpshot:
AE - Pumpshot vs. Differential TPS
is the name of the table
Is this the change in the TPS value from 0 - 12.5% determines how much usec to add. So if I blurp the pedel only 6.3% it would only add that much usec and if I did 0 to 100% WOT slam than it would add the 12.5% usec value? BTW, usec means units per second right? So increasing will add fuel?
Power Enrichment:
PE - WOT air fuel ratio vs. RPM
is the name of the table
Is this the actual PE adder to the main VE tables?
Pumpshot:
AE - Pumpshot vs. Differential TPS
is the name of the table
Is this the change in the TPS value from 0 - 12.5% determines how much usec to add. So if I blurp the pedel only 6.3% it would only add that much usec and if I did 0 to 100% WOT slam than it would add the 12.5% usec value? BTW, usec means units per second right? So increasing will add fuel?
Power Enrichment:
PE - WOT air fuel ratio vs. RPM
is the name of the table
Is this the actual PE adder to the main VE tables?
Last edited by WhiteHawk; 07-27-2005 at 09:00 PM.
07-27-2005, 10:02 PM
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Car: 91 Red Sled
Axle/Gears: 10bolt Richmond 3.73 Torsen
usec isn't units per second it's microseconds. I haven't sat down and calculated the "12.5% TPS" but it's a delta meaning 12.5% TPS movement over some specific time value (usually very small). If RBob's reading this he might know off the top of his head and I can change the table to display an easier to visualize term instead of %.
From memory, it's actually very hard to even get to the 12.5% table entry. You need to be superman according to RBob. The 7747's TPS AE table goes up to 25% but it uses a different time so it's easier to get up to those "larger" values.
Just experiment but it's mostly the first 3 tables in the entry that'll ever get used, even when slamming the throttle to the floor. For this reason, the MAP AE is worth more to getting the AE dialed in.
As for the PE AFR table... well that's not an adder. Those are actual desired AFR's. With the 8746, it will lock the BLM's to 128 so then it's assuming the VE table values are for a 14.7 AFR (stoich). Now let's say the PE AFR table entry is 12. The ecm will then command for an AFR of 12 instead of 14.7 . Richening the mix through whatever math it uses. This is why it's good to get the VE tables close to 128, this way the commanded AFRs are closer to actual.
So to review, it's not an adder, it's a multiplier.
From memory, it's actually very hard to even get to the 12.5% table entry. You need to be superman according to RBob. The 7747's TPS AE table goes up to 25% but it uses a different time so it's easier to get up to those "larger" values.
Just experiment but it's mostly the first 3 tables in the entry that'll ever get used, even when slamming the throttle to the floor. For this reason, the MAP AE is worth more to getting the AE dialed in.
As for the PE AFR table... well that's not an adder. Those are actual desired AFR's. With the 8746, it will lock the BLM's to 128 so then it's assuming the VE table values are for a 14.7 AFR (stoich). Now let's say the PE AFR table entry is 12. The ecm will then command for an AFR of 12 instead of 14.7 . Richening the mix through whatever math it uses. This is why it's good to get the VE tables close to 128, this way the commanded AFRs are closer to actual.
So to review, it's not an adder, it's a multiplier.
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