SY 3500 kills Fuel Economy??
11-11-2004, 02:38 PM
#1
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SY 3500 kills Fuel Economy?? Hey Everyone,
I got my Stall converter installed last week and now it seems that my Fuel Economy is going down hill. I used to get 250-260 now am getting 230-240. I thought that the SY 3500 didnt kill fuel economy... Anyone care to enlighten me?Thanks
I got my Stall converter installed last week and now it seems that my Fuel Economy is going down hill. I used to get 250-260 now am getting 230-240. I thought that the SY 3500 didnt kill fuel economy... Anyone care to enlighten me?Thanks
11-11-2004, 04:23 PM
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yeah i havent tuned it yet... hopefully after the cam i want to get it tuned. Just wanted to make sure that it wasnt an isolated incident. .. Thanks ya'll
11-11-2004, 05:14 PM
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I saw no economy drop going from stock to my
TCI SF3000, but I never saw any 250 miles to
the tank, neither, to begin with. Maybe on straight
highway, but I never did a long highway trip with
the stock converter.
If it's your highway mileage dropping, might want
to check out whether the lockup clutch has more
slip than the stocker (my TCI does, not bad at
light load but slipped a lot more on hills; I had to
up the line pressure a lot in the light-load region
to make the TCC hold).
TCI SF3000, but I never saw any 250 miles to
the tank, neither, to begin with. Maybe on straight
highway, but I never did a long highway trip with
the stock converter.
If it's your highway mileage dropping, might want
to check out whether the lockup clutch has more
slip than the stocker (my TCI does, not bad at
light load but slipped a lot more on hills; I had to
up the line pressure a lot in the light-load region
to make the TCC hold).
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11-11-2004, 05:58 PM
#8
Must have more of a lead foot than I do, although I floor it every chance I can get. lol. My highway driving never gets out of the city either. I've never heard of tcc slip after it locks up under light load. Wouldn't that burn the clutch up right away?
11-11-2004, 06:44 PM
#9
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No, the clutch is in the converter and is a wet clutch
so it gets some cooling. The clutch is "expected" to
slip under load, I think, just seems to happen mighty
early on mine.
I'm talking about maybe 100-200RPM
but on hills, I even got a slip code (trans got hot, line
pressure came down, holding power dropped). I had to
redo the force motor table temperature profile, it was
sort of a positive-feedback deal (more slip = more heat
= lower line pressure = more slip).
The SY3500 is supposed to be about the most efficient
converter out there if I recall right.
so it gets some cooling. The clutch is "expected" to
slip under load, I think, just seems to happen mighty
early on mine.
I'm talking about maybe 100-200RPMbut on hills, I even got a slip code (trans got hot, line
pressure came down, holding power dropped). I had to
redo the force motor table temperature profile, it was
sort of a positive-feedback deal (more slip = more heat
= lower line pressure = more slip).
The SY3500 is supposed to be about the most efficient
converter out there if I recall right.
11-11-2004, 09:17 PM
#11
Jimmy, Sounds like it is starting to get worn. Mine feels like a stocker when in lockup mode, almost m6 ish. if i'm coasting and nail the gas right up to the point before it'll unlock i'll get about 100rpm of tip in slip but it'll fall back in half a second while under accleration
11-12-2004, 05:46 AM
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Originally Posted by Ragtop 99
If that was a mix of city and highway, a 1 mpg drop is not bad for a 3500 stall. Wait till the cam is in. if it is decent size, you'll lose another 2+ MPG in town. 
2 MPG? I wish....More like 10 for me but I wouldnt go back to stock for anything. Its well worth the smile on my face every time I start it up
11-12-2004, 10:17 AM
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Mine has never been right since the B&M Trick Shift
fiasco (put in at install, emergency flush 500 miles
later). Couldn't say whether a TCI SF3000 that was
properly fed, acts the same or not. I would be interested
to see anybody's highway, TCC slip vs TPS% logs to
compare the same converter un-buggered.
fiasco (put in at install, emergency flush 500 miles
later). Couldn't say whether a TCI SF3000 that was
properly fed, acts the same or not. I would be interested
to see anybody's highway, TCC slip vs TPS% logs to
compare the same converter un-buggered.