yank py3400 TIGHT
08-18-2011, 04:10 PM
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yank py3400 TIGHT I have a 4l80 with a yank py3400 and got it broke in. When trying to foot brake it, it goes to about 2200rpm's then it starts pushing the car or spinning the tires. My car doesn't make power till about 3500 rpms and it won't even spin the tires on the street with 450whp. Any thoughts?
08-18-2011, 04:19 PM
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Well, foot-braking my probably-"looser" Fuddle
(3500/2.0) will also overwhelm the rear brakes
before I get past 2500 or so. That's where the
max torque multiplication is. But it doesn't mean
a whole lot in my book; you want more RPMs
while going nowhere? No, you want a converter
that keeps your shift-to RPM up near peak power
and your shift-from RPM about the same power
on the other side of peak.
Sounds like it's decently streetable, question is
more whether it's a good fit to the motor power
band. Log something like a 1-2-3 gear WOT pull
and see top of 2nd RPM and bottom of 3rd, and
mark those on your dyno graph. If you're straddling
the peak pretty well, call it good. You're looking to
minimize "time away from max HP".
(3500/2.0) will also overwhelm the rear brakes
before I get past 2500 or so. That's where the
max torque multiplication is. But it doesn't mean
a whole lot in my book; you want more RPMs
while going nowhere? No, you want a converter
that keeps your shift-to RPM up near peak power
and your shift-from RPM about the same power
on the other side of peak.
Sounds like it's decently streetable, question is
more whether it's a good fit to the motor power
band. Log something like a 1-2-3 gear WOT pull
and see top of 2nd RPM and bottom of 3rd, and
mark those on your dyno graph. If you're straddling
the peak pretty well, call it good. You're looking to
minimize "time away from max HP".
08-18-2011, 08:51 PM
#3
How high does the engine go when you flash it? Meaning, when you launch in 1st gear from an idle.
And Jimmyblue is spot on... Just because the rear tires break loose when foot braking the converter does not mean it's too tight.
Another term for what he's talking about is shift extension. Let's say that the tranny shifts at 6,500 rpm. The question is how far does the converter tug the motor down after the gear change..if it's 400 to say 600 rpm, then thats ideal. But if it falls more than 900 rpms then yeah the converter is too tight.
g
And Jimmyblue is spot on... Just because the rear tires break loose when foot braking the converter does not mean it's too tight.
Another term for what he's talking about is shift extension. Let's say that the tranny shifts at 6,500 rpm. The question is how far does the converter tug the motor down after the gear change..if it's 400 to say 600 rpm, then thats ideal. But if it falls more than 900 rpms then yeah the converter is too tight.
g
08-18-2011, 09:17 PM
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I understand about the shift extensions but when I hit it from idle it goes about 2500 rpms and won't even spin. It does great up top. I'll try and get a video of what I am talking about. It was built for nitrous but just doesn't feel like it would 60ft good on the motor.
08-19-2011, 10:45 AM
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450hp and cant break street tires loose on the street is a huge problem IMO. Something is amiss. I would gather as much info as possible (brake stall speed, flash speed, shift extension) and call Dave at Yank and tell him what you've got. Maybe he spec'd it for you to spray out of the hole.....
08-19-2011, 02:49 PM
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The 4L80 does have a shallower 1st gear than the
4L60. Don't remember how much so.
I don't understand. First post says they spin at 2200,
now they don't.
On my setup it will light off from sitting or a roll, up to
40+ MPH and I probably put less to the wheels than
you say. But wheel HP is not the story when it comes
to that, low RPM torque is. You sacrfice some of that
(perhaps) with a big cam.
But I am not seeing a clear story here anymore.
4L60. Don't remember how much so.
I don't understand. First post says they spin at 2200,
now they don't.
On my setup it will light off from sitting or a roll, up to
40+ MPH and I probably put less to the wheels than
you say. But wheel HP is not the story when it comes
to that, low RPM torque is. You sacrfice some of that
(perhaps) with a big cam.
But I am not seeing a clear story here anymore.
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08-19-2011, 02:56 PM
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i dont have a big cam, lol i have a torquer v.2 with 461tq in a stroked 408 with 4.11 gears. it spins them in my slick garage floor, not on the road. Sorry for the misleading comment. It should blow the tires off anytime i want it to. With the 6speed it made 470hp 490tq with no problems burning the hides. ran a 7.50 @ 94mph in a 3900lb car. Switched to an auto for better 60ft's and i cant even turn a tire. Im just venting i guess.
08-21-2011, 11:45 PM
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I'm assuming you have decided to send in into Yank and get it restalled. We use PY3400's for Big hit N2o and Supercharges/Turbo motors. Way to tight for your combo. Something that flashes to atleast 4000 rpm will make a world of difference.
08-22-2011, 12:05 AM
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^^^agreed....
Well then you have defective tires or a factory freak....though my car hasn't been bone stock since I have owned it (came with mods), I seriously doubt when I first bought it that it would light up ET Radials.
Well then you have defective tires or a factory freak....though my car hasn't been bone stock since I have owned it (came with mods), I seriously doubt when I first bought it that it would light up ET Radials.
