CONVERTER SLIP %

hensleyt

hensleyt

Well-Known Member
Joined
Feb 20, 2008
Took my power logger and ran the numbers,my though was locking it to help my ET,it looks good or dose it?
MPH RPM %
80 4795 31.56
85 4771 26.9
90 4890 24..5
95 4964 21.49
100 5066 19.0
105 5200 17.0
110 5284 14.6
115 5372 11.69
This is from the Wallace calculator
 
You can put the gear ratio numbers in the powerlogger and it will automatically show the converter slip. Little easier than having to calculate them yourself.
There is a thread that shows the figures you need to input.
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(69 RS Clone)your build is like mine What dose you converter % show at those speeds? My car ET 11.82 @115 mph ,my goal of 11.5 @ 117-118.
I was trying to decide with these numbers should I be locking this converter or not? Track prep is poor all the time so I'm trying to keep my 60 foot in the 1.7 range and work the top part of the track .
 
First, the tire size won't affect the ratio of the converter slip. It is comparing the engine rpm to the tailshaft rpm. Regardless of tire size and rear end gears, it won't change the output.
The one and only time I made it to the track the past year I ran 11.88 at 112mph. 1.67 60'. Was running 24 psi with base chip settings, and chip is for a stock D5 converter. I was taking it easy due to an early season head gasket failure. I will look into my logs and see the slip.

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OK, looked into my log and I was turning 5300 across the line with 8.8-9.6 % slip. I am running 26" tires so that explains the higher rpm.
 
i wish i could get a 1.67 ,1.75 is the norm on a slick,with good suspension work.
yes I have moved the numbers around on the logger for slip % .I think the calculator will be a little closer
I see you have a new Husk converter is it a lockup?
 
Yes, it is a lock up. I have virtually nothing done to the suspension other than boxed rear control arms, bilstein shocks and some homemade braces. Running worn-out 255 DR's and still on original springs, no bags. I am leaving on the 2 step which definitely helps. Set to 2600 rpm, 8 psi when I let off the brake and 24psi in 0.5 seconds. The powerlogger doesn't even register mph before I'm at 24 psi.

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I don't think your converter is meant to be locked at WOT, I would check to make sure. While you're slippage isn't the worst I've seen, it looks like you could benefit from a better matched converter. If you had 3% less slip you'd be in the 118mph range. Throw in a better 60ft and you are in the low 11 range. If you want to keep lockup you'd need to go to a multidisc setup, or you could go to a nonlock converter which is more efficient unlocked but you will lose lockup for cruising and daily driving.

And 1.75 is a pretty bad 60ft at that power level. I would go through the suspension to see whats going on if its spinning, maybe its unloading or something. Even with an average track you should be able to get 1.6s. And you are on slicks which recover well compared to drag radials so you can spin through the initial hit.
 
Its a EDGE convertor and they say lock it if i want to.
murphstr do you think I should be that tight 3% .what about my 85-90 mph %
I have picket up my 1/4 speed up from 112 to115 but my 1/8 is 91 still
its vary disappointing to have such a slow 60,I have UMI uppers and lowers KYB shocks and back to the stock spring (It had cargo springs) my best bolt on was the Helwig bar,went from 2.2 to 1.75.
Im going to ask in the suspension part about the HR bar at my power.
Thank you for your time
 
What rpm and/or boost are you leaving at? How fast is your turbo spooling up? I do 1.6's on 60ft leaving at 2800rpm and no boost. All stock bushing from '87, ATR rear bar and 36mm IROC front bar, stock replacement shocks.
3928.jpg
 
hensleyt said:
Its a EDGE convertor and they say lock it if i want to.
murphstr do you think I should be that tight 3% .what about my 85-90 mph %
I have picket up my 1/4 speed up from 112 to115 but my 1/8 is 91 still
its vary disappointing to have such a slow 60,I have UMI uppers and lowers KYB shocks and back to the stock spring (It had cargo springs) my best bolt on was the Helwig bar,went from 2.2 to 1.75.
Im going to ask in the suspension part about the HR bar at my power.
Thank you for your time
Click to expand...
Let me spare you the trouble.without any mods to the suspension I went 1.58 with a 49 turbo years ago at 3800lbs with suspension mods and a hotter tune,high 1.4s .converter and tune and tires are huge.need to look at the converter because I have chased my own tail in the past trying a few,too loose and it leaves good but no mph too tight and it doesn't 60ft well.yours looks loose but you have no 60ft,need to leave on more power and lock that converter down up top if it can handle it.
 
All of you are right. My biggest problem is my 60 it is so inconsistent .I have a two steep,my breaks can hold about 8 lb at the light,i run 28X9 Hooser,I let go of the break and all i do is spin the tires ,the street in front of my house has more traction .I think by slowing car down in the 1/8 this year it will be a little more consistent in the 1/8 ET and 60. then run it out a little harder on top,it shifts into 3ed just before the 1/8.
I look at the numbers on slip % and it looks a little loose to me.
Mr.spool if it looks loose up top to you,then i think ill try locking it around 85 - 90 around 4800rpm
PS i have a good D5
 
I hear tractor fluid will slightly tighten a loose converter a little. Could try that.

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If it spins leave at a lower rpm/boost. Start at 2 psi and work up. The thinner tractor fluid can loosen converter but why? More slip on the big end and he is spinning on the launch. Work on the launch.
 
hensleyt said:
All of you are right. My biggest problem is my 60 it is so inconsistent .I have a two steep,my breaks can hold about 8 lb at the light,i run 28X9 Hooser,I let go of the break and all i do is spin the tires ,the street in front of my house has more traction .I think by slowing car down in the 1/8 this year it will be a little more consistent in the 1/8 ET and 60. then run it out a little harder on top,it shifts into 3ed just before the 1/8.
I look at the numbers on slip % and it looks a little loose to me.
Mr.spool if it looks loose up top to you,then i think ill try locking it around 85 - 90 around 4800rpm
PS i have a good D5
Click to expand...
Put a 28 with a 10.5 contact patch on the car and load the boost and lock the converter you will go faster than you ever have been.loose the 9 inch tire
 
hensleyt said:
Its a EDGE convertor and they say lock it if i want to.
murphstr do you think I should be that tight 3% .what about my 85-90 mph %....
Click to expand...

I said 3% less slip, not 3% slip overall. Just saying that having less slip should help your mph, either by locking it or a better converter setup.

And I agree, going to a 28' tire with10.5 should help on a crappy track,
 
I have an edge single disc in my car as well. I would not lock it as it's not intended for that. Here's some data from a 600rwhp car that spins 6200rpm. At shift it slips 10.6%. Have been 1.29 60' with a brake. Black line is converter slip, yellow is rpm.
 

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20psiofevil said:
I have an edge single disc in my car as well. I would not lock it as it's not intended for that. Here's some data from a 600rwhp car that spins 6200rpm. At shift it slips 10.6%. Have been 1.29 60' with a brake. Black line is converter slip, yellow is rpm.
Click to expand...
1.29 with 600rwhp?please don't take this the wrong way but 1.29 60ft needs way more power than 600rwhp.is this a one time thing or does the car run that kind of 60ft on most passes?
 
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