11% Slip with locked single disc

[Alky V6]

You're right. Just wanted to be sure everything was being considered. That's a lot of slippage locked up.

You're right too, Dave.:tongue:

 

[BEATAV8]

Since you're running the stock computer and 28" tall tires have you changed your speedometer gears out so your MPH is reading accurate? Your actual speed is MORE than your power logger shows since the car is set up for 26" tall tires. This will effect converter slip numbers. Am I correct?

I've been using timeslip MPH. But either way 5700 rpm for 26" @ 115mph or 28" @ 125mph is just about the same slippage.

 

[Turbo1dr]

Well I tried locking my Vigilante single disc this weekend.

Previously: ~18% slip unlocked (6000RPM @ 125.6 on 28" tire)
This weekend: ~11% slip locked (5700RPM @ 125)

Car has been running 10.70-11.00 @ 125 with relatively soft launches.

Drops 600 RPM on shifts
Drops 300 RPM when it locks @ ~92MPH
Stalls ~2000RPM 0 boost and ~3600RPM 15 PSI boost (does this make sense or am I reading my data wrong?)

I'm thinking it's just a tad too loose for my turbo. The double ball bearing 6776 is spooling really fast with this converter.
I'm gonna talk to them and see if they will tighten it up a bit and ask if they can upgrade my unit to a multi-disc.

What do you guys think I could expect from tightening it up a couple hundred RPM? Will I see the un-locked RPM come down by a couple hundred RPM on the big end? Will my shifts see the drops of 800 RPM instead of 600 RPM?

I have been playing with converter slippage on my car now that this thread seems popular.

MJRWOOD, do you have the part number on your converter? It should start with a 239*** number.

I've been testing torque converter slippage using the figures below in an on-line slip calculator.

Here is what I get with my converter. Vig part number 239425

TIRES = 28"
REAR = 3.42
TRANS RATIO = 1.1


RPM = 5300
MPH= 75 56% slip

RPM = 5950
MPH= 109 21%

Below is with the converter locked up...

RPM = 4200
MPH= 84 <--- data log looked like the converter clutch was slipping at this speed even though the converter was locked. It had a nice rise in rpm in that area.

RPM = 5950
MPH= 130

Here's what it does foot braking it...
Boost...... RPM
0............2700
3............3050
5............3250
7............3450
10...........3700
12...........3900

TIRES STARTED SPINNING...
15...........4150 mph showed 4 on data log
17.5........4500 mph showed 8 on data log


According to Precision if your converter has a "1" second to the last number it doesn't have what they call a "turbo stator" in the converter. If it has a "2" it does. Like these units I've had... 239615 and 239425.
The numbers "6" and "4" is what pump it is.

 

[wickedtt]

And what does a turbo stator do for you that the reg. one doesn't?

 

[Turbo1dr]

And what does a turbo stator do for you that the reg. one doesn't?

I have no idea. Maybe he was blowing wind up my arse for all I know?

 

[BEATAV8]

MJRWOOD, do you have the part number on your converter? It should start with a 239*** number.

I dunno which one I have I'll have to post when I pull it out and have a look.

 

[Dusty Bradford]

The turbo stator is what you want. When I ran the Vig I sent it back 3 times until they got it right. I ended up with the 0 pump and turbo stator. I could blow right through the version without the turbo stator.

 

[BEATAV8]

My PTC is in the car!

Thanks Dusty, converter feels great. No data yet but I can definitely feel more thrust and fewer engine revs.

Turbo1dr.. I owe you a precision P/N. Will post it shortly.

The trans looked great when we had it opened up.

 

[Dusty Bradford]

Great. Let me know how it works..

 

[BEATAV8]

Turbo1dr... the only number stamped on the Precision converter is 37595s. I'll look it over really closely once again in the morning, but that's all I've found so far.

 

[Turbo1dr]

I have already gotten mine restalled down to a 2800 (#239425).


I talked to Precision and this is what they said...

part number:
239425 is a 2800 stall
239025 is a 3200-3400 stall
239615 (no turbo stator) is 3600+ stall
239725 is a 3800+ stall



Below is an XFI datalog of the 2800 stall converter while foot braking.

Boost..... RPM
0............2500
3............2850
5............3000
7............3200
10...........3500
12...........3650
14...........3800