When IAT is unhooked it reads -39...how about modifying these tables for nitrous.
06-21-2009, 05:17 PM
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When IAT is unhooked it reads -39...how about modifying these tables for nitrous. If we un hook our iat sensor, it registers as -39 degrees. When viewing hp tuners, the iat tables do not go that low. My question is when the iat is unhooked, does the computer just default to the lowest tables in the ecu? I believe this is around 32 degrees.
What I am getting at here is it possible to unhook the iat then use this as a timing retard for nitrous. Basically modify the lowest tables in hp tuners to pull 8 degrees of timing, or whatever it ends up being?
What I am getting at here is it possible to unhook the iat then use this as a timing retard for nitrous. Basically modify the lowest tables in hp tuners to pull 8 degrees of timing, or whatever it ends up being?
06-21-2009, 06:48 PM
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Yes, thats an old trick from the way-back machine. Put a toggle switch in the IAT wire to break the circuit then reprogram the table and you have a simple timing retard setup.
06-21-2009, 08:00 PM
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find someone with EFI LIVE and get them to use Custom OS5 with its NOS support. You then wire a switch to a spare pin on J2 Pin 56. when the switch is grounded the nos talbes come into action which not only trim timing to your choice but also gives modified fuel control, which the hack method mentioned above wont do.
06-21-2009, 08:08 PM
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find someone with EFI LIVE and get them to use Custom OS5 with its NOS support. You then wire a switch to a spare pin on J2 Pin 56. when the switch is grounded the nos talbes come into action which not only trim timing to your choice but also gives modified fuel control, which the hack method mentioned above wont do.
Well I have a iat tricker that activates when the nitrous is active. It is a resister hooked to a relay. When hooked up normally it reads 201 degrees. When hooked up backwards it reads -38.
What I want to do here is retard the 201 table to cover a 100 shot, and retard the -38 table to cover a 175-200 shot.
Is this possible?
That way, when I change jets I can just reverse the leads.
06-21-2009, 09:28 PM
#5
find someone with EFI LIVE and get them to use Custom OS5 with its NOS support. You then wire a switch to a spare pin on J2 Pin 56. when the switch is grounded the nos talbes come into action which not only trim timing to your choice but also gives modified fuel control, which the hack method mentioned above wont do.
Actually the 'hack' method DOES provide fueling changes at WOT only when active too... You should know since we have Holden to thank for the tables becoming active in our cals. There is an IAT PE modifer that can, with a little forethought and understanding be used to either add OR subtract fuel at WOT on the jug, besides being able to modify timing.
06-21-2009, 10:53 PM
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Actually the 'hack' method DOES provide fueling changes at WOT only when active too... You should know since we have Holden to thank for the tables becoming active in our cals. There is an IAT PE modifer that can, with a little forethought and understanding be used to either add OR subtract fuel at WOT on the jug, besides being able to modify timing.
Thats a good point, so the hack method does provide enough scope for control. I forgot about that table as I never use it. But what do you have for IAT compensation control once on the bottle? If you bottom out the IAT and run the bottle at 0c ambient and then again at 40c ambient you have no control to compensate between the two. If you just choose a suitable resistor to fit to effectively drop IAT 40c there might be minimal crossover.. But I still think there may be situations where there will be and hence its still not a perfect solution.
06-21-2009, 11:17 PM
#7
You have some AFR wiggle room on the spray, so it's not really an issue. I have used 2 stages of resistors and sprayed as much as 350whp worth very successfully like this using the PE modifier to tweak WOT. There was a 200 DP shot and 150 from a nozzle. To avoid jet changes we did it in the PE modifier. This guy has gone through some nitrous too...
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06-22-2009, 05:16 AM
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Does anyone know if I make the lowest tables in the ecu (the 32 degree ones) pull 8 degrees of timing. Then unhook the iat sensor to make the -39 show up. Then make a full throttle run will the 8 degrees of timing be pulled?
06-22-2009, 08:30 AM
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You can cobble up a relay that runs off the arming
(-40 all the way) or solenoid (-40 only when shot)
to "trick it" automatically. Cut the wire, attach across
the NC/COM terminals of the relay. So normally you
read IAT straight up, until it energizes.
(-40 all the way) or solenoid (-40 only when shot)
to "trick it" automatically. Cut the wire, attach across
the NC/COM terminals of the relay. So normally you
read IAT straight up, until it energizes.
06-22-2009, 09:12 AM
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I want to have the ability to run more than one shot. Let's say I set the 201 up to pull 12 degrees and run a 175 shot.
Could I set the 32 one up to pull 6 degrees and unhook the iat and run a 100 shot?
06-22-2009, 04:16 PM
#11
It will work, but keep in mind that from what I can see, opening up the IAT ckt instead of replacing it with a ranged load will put the car in open loop. Obviously this isn't an issue during the run, but if some hack shop tuned your car, you can count on it to run poorly in OL.
06-22-2009, 08:05 PM
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06-22-2009, 08:33 PM
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Also have a wideband and aeroforce scangauge to monitor things.
