I have a Yank SS3800 in a 4800lb 4wd truck with an ATI procharger running 11psi.

When I first got my Yank SS3800, it stalled to about 3900 and shift extension was about 4900. Since then, I've added about 70 flywheel hp. It's now stalling to about 4300, and shift extension is about 5300.

Logging TCC slip speed shows slip through the converter at 400-1100rpm in second gear, and 700-1600 in third gear. The highest slip is at about 5400rpm in both gears. It looks like a big spike slowly tapering in my logs. (the TCC is unlocked the whole time BTW)

My question is, when do you know you're blowing through a converter? Are there any hard numbers to go by?

Anyone ever blown through a converter before?

 

That converter is not for a s/c use in a truck and you will need to shift at 6400 and thats out of your power band!
your better choice will be an ss3200 or a pt3200
we can rework you ss3800 to an ss3200 for you!
call DAVE at 775 826 9955

 

So are these the symptoms of blowing through it? Or am I just shifting too low?

 

You are not blowing thru the converter!
that is when you do not have very much around 200 or no drop in rpm after the shift .
what you have might be too much stall for your Taste or driving style.

But more rear gear or a tighter converter might help drivabilty for you.
but it may also go slower with a change as now you ar getting extra torque from the extra shift extention.
shifting at a higher rpm will also help in the ET and mph dept.
you might try 200 rpm at a time increase and see what happens

 

To know whether you're blowing through it, it helps to know where peak TQ and peak HP occur and the shape of the HP curve from ~ 500 rpm below peak tq to 500 rpm above peak HP.

 

Thanks. It's good to know I'm not blowing through it.

Driveability isn't that great, but I did gain 1.5 seconds and 7 mph from a TT3000. So I have to say, it kicks *** at the track!

I'll try a little higher shiftpoint.

 

I've never had it dynoed, but it is a centrifugal charger, so I would imagine they both peak pretty high.

 

What rpm are you shifting at? 5400 extension with 6200 rpm shift or higher isn't bad.

At what rpm do you reach 11lbs? If you acheive 11lbs by 5000 rpm, you may do better with a tighter converter. If it doesn't show up untill 5500 rpm and you shift over 6k, you're ok.

 

I'm shifting at 6000. I see 11psi at 6000, and about 9 at 5300.