Just wanted to know what people were using for a shift point with their nitrous. I haven't had a chance to datalog yet so just curious how high of an RPM to set the window switch. Also with the predator can I set the shift point? I'm not sure which parameter that is. (rev limiter in drive?) Thanks
Edit: I am also curious about my AF readings on the stock tune as I am getting mid 11's. I believe that this is a little rich should I remove some fule with the predator and if you think so what's you best guess as to how much? I am shooting for low to mid 12's if I'm not mistaken.
Last edited by Padre Prince; 10-28-2009 at 04:45 PM.
"THAT'S WHAT'S UP"
If you dyno your car, you might be surprised that with nitrous, peak power and peak torque may happen at a lower rpm than even stock. My RT Magnum without the Sidewinder= Max power 294.3hp@5145rpm and max torque was 314.1ft/lbs@ 4813rpms. With the Sidewinder and a 100 shot Max power was 401.8hp@ 5001rpms and a stump pulling 452.2 ft/lbs@ 4667rpms. Now I can't say if the cam or the nitrous actually lowered the rpm power range, suspect the nitrous more than the Sidewinder. This was on a very conservative Mustang dyno. Probably add 35-50 hp and ft/lbs with a DynaJet. I wouldn't go over 6,000 rpms on the shifts, might try even lower. As far as A/F ratio I would defer to the tech support guys from your kit Zex, Nitrous Express, etc. I always either run race gas or a bottle of NOS brand octane booster when I spray. My track is only an eighth mile, so are you running around 7.5/90-91 mph in the eighth? I would set the bottom window switch at 2800-3000 as long as you can keep from breaking traction. The MT's let me spray at just above 2800 with good track prep. I would flash the converter to 2800, it would spin 1 revolution then upon hook-up I would hit the blast-off button. (No window switch)
Last edited by formerice; 10-25-2009 at 01:56 PM.
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mine is set to 2700-5900 gears 2 and up
You can increase the shifts through the Predator. Just go into the transmission menu and select raised shift points. You'll also want to raise your rev limiter to about 6600.
Also, you want to stay around 11.5:1 a/f on nitrous. N/A you can get away with 12.5:1 but no with the nitrous.
You'll have to play around with the window switch to see how your car launches best. If you're using drag radials you should be able to spray out the hole not need the window switch.
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Thanks guys! I have run the car once on the track and I guess that my shift point is a little low @ 5400. I set the spray to engauge at 2800 and my tires held fine I think they have 2700 in them (255/55/18 Toyo Proxies STII) even lower if I get to try out Nate's radials. Although I am not sure if the axles will take a 100-125 out the hole on DRs? Anyway thanks for the help I think I will see some lower times in the near future.
typically our axles can take the abuse as long as you dont *wheel hop*
if you load up the axles, hop (unload), then stick em, thats when bad things happen.
so if you feel the wheels bouncing, get out of the gas lol.
give me a call if you have any questions about Shiftpoint/Rev Limiter, i can walk you thru it with the predator and explain how they relate (there is a difference between those two)
stock shifts points are pretty low, and you may not need to raise em at all really, the stock cam doesnt breath as well up past 5800, but i did find some gains from raising it to 6000 rpm because of the shift recovery into the next gear.
'99 FRC Corvette - Far From Stock
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I don't think I have the feature to change the shift points. Is this not included in the predator for a 2008? WTF
i believe u need the upgraded tcm for the 2008 model to have a higher shift point. its like 1000$
i thought that didnt come around until 2009?
are you modifying the tune? or trying to do quick adjusts?
I have looked at both ( I think ) and saw nothing that would allow me to change the shift points. I am trying to get a tune for the 125 shot maybe the 100 as well. Hopefully the tuner can adjust the parameters for me.
Wow, only 1000 dollars. What a deal. Ok so I guess that for now I will use the stock points. Correct me if I'm wrong, but is that 5800?
i think its 5500 in first and 5800 in the rest, been too long since ive looked,
do you have EVIC? (hold the music note and the compass buttons for 10 seconds)
if you have the steering wheel options
this will give you a diagnostic mode, you can use the up/down arrows to scan thru them til you get to the one with the digital Tach readout,
you can watch exactly where it shifts there (if you have it)
to change the shift point you have to
-custom tunes (or diablo tunes if your using a canned tune
-select your tune
-it asks if you want to install tune or modify
-select shift point
-set for 6000
-select rev limiter
-set for 6400 or more
-press ESC button a few times
-it asks do you want to write this tune?
or... if there is no rev limit/shift point under the "transmission" section of the modify tune... then i guess you dont have it :( :( :( :(
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the idea of setting the limiter way high is so that you dont rev thru your shiftpoint in first gear and smack the limiter causing power loss/slow shift.
i set my limiter at 6750. period. even if my shift point was at 5500.