Tuning help
Thread Starter
TECH Enthusiast
Joined: Feb 2002
Posts: 551
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From: chicago
Tuning help Taking the plunge this weekend. I have purchased HPTuners and I am going to learn if it kills me. I have a 422 with LS1 heads. 236/242 112 .599/.603. FAST 90mm 90mm mafs. 11:1 compression 42# injectors. Automatic TCI Super Street Fighter. About 4000 stall. Any help would greatly appreciated.
In my book the first thing to do is get a handle on your
fuel pressure and then make sure the injector table is
right for the injector model and that. There's a good
spreadsheet for it. You can probably find some good
info on the offset and short-pulse stuff in the tune
repository and 'board discussions. The reason is, this
is stuff you can do from "first principles" with a pretty
good accuracy and get it off the table. Then AFR
tuning is all about air model (MAF, VE) and intention
(PE, EQ vs ECT vs MAP). You have to knock down as
many unknowns as you can or you'll tangle yourself up.
Now that MAF is probably a "mystery piece" but you
may try hitting up the mfr for a proper flow/freq table.
I'm not too optimistic about your TSI SSF holding motor
torque at cruise. You may want to work over the General
Pressure, TCC Locked (if that's available to you) or the
force motor table otherwise the lockup clutch will have
nothing to work with, is my experience with that. You
will probably do a lot of playing with lock/unlock points
as well. Don't bother trying to lock it on the dyno, it's
way too weak a piece for that.
fuel pressure and then make sure the injector table is
right for the injector model and that. There's a good
spreadsheet for it. You can probably find some good
info on the offset and short-pulse stuff in the tune
repository and 'board discussions. The reason is, this
is stuff you can do from "first principles" with a pretty
good accuracy and get it off the table. Then AFR
tuning is all about air model (MAF, VE) and intention
(PE, EQ vs ECT vs MAP). You have to knock down as
many unknowns as you can or you'll tangle yourself up.
Now that MAF is probably a "mystery piece" but you
may try hitting up the mfr for a proper flow/freq table.
I'm not too optimistic about your TSI SSF holding motor
torque at cruise. You may want to work over the General
Pressure, TCC Locked (if that's available to you) or the
force motor table otherwise the lockup clutch will have
nothing to work with, is my experience with that. You
will probably do a lot of playing with lock/unlock points
as well. Don't bother trying to lock it on the dyno, it's
way too weak a piece for that.
Thread Starter
TECH Enthusiast
Joined: Feb 2002
Posts: 551
Likes: 0
From: chicago
Thank you the maf is a later model 5 wire with the iat sensor included. The car was tuned by a shop in the past. It was never right. Idle timing is at 36° and it ghost idle cruises at 40mph. I have just added the bigger intake and related components. The trans is a pure evil stage 4 with vacuum modulator to control trans pressures. If I can lock up will be cruising high gear only.
In that case, if the MAF is a true unmolested Delphi piece (not a SLP)
then I'd check the table in the tune against a Z06 MAF (if no screen)
or a truck MAF (w/ screen, but I think that motor wants no steenkin'
screen). You're in a position of checking other peoples' work. To that
end the "compare" function against a stock F-body tune for your year
(or the year appropriate to the OS the tuner used) will be a good way
to see what-all has been touched; might want to make yourself a list
and check it twice, because somebody's been naughty.
then I'd check the table in the tune against a Z06 MAF (if no screen)
or a truck MAF (w/ screen, but I think that motor wants no steenkin'
screen). You're in a position of checking other peoples' work. To that
end the "compare" function against a stock F-body tune for your year
(or the year appropriate to the OS the tuner used) will be a good way
to see what-all has been touched; might want to make yourself a list
and check it twice, because somebody's been naughty.
Thread Starter
TECH Enthusiast
Joined: Feb 2002
Posts: 551
Likes: 0
From: chicago
Yes truck maf no screen. Unmolested. At 950 rpm the tb is showing 1% with .63volts the iac is at 70 with 36° of timing. Surging mess trying to come back down to idle and will die out most of the time. This is PSJ's original 422 I bought from him in 01 02 ish. Thanks for your help. I may message you if I get totally lost.
