This can't be right (can it?)

Posted By: WILD BILL

This can't be right (can it?) - 09/21/11 09:54 PM

I'm using Wallace Racing Calculator to determine my Conv slip %

Using 132.66 mph/7000 Rpm at the line/ 4:56 gear ratio/ and the advertised roll out of my tires as 97"

I came up with 17.511 %

I tried varying the rpm and tire size a little figuring I might be going a little under what I think I see on the tack or thinking I might have to acct for tire growth but it still comes in as what I think is a way high slip percentage.

For some reason I was expecting somewhere around a 5 or 6 % number.

Can this be right?

Posted By: sunroofgtx

Re: This can't be right (can it?) - 09/21/11 09:59 PM

That would put you around 1150 horse adjusted ! Not far off.

Posted By: StrokerAspen

Re: This can't be right (can it?) - 09/21/11 10:02 PM

HM.... I come up with 6.5% slip... I am using a diameter of 31" is this correct?

-Kenny

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/21/11 10:08 PM

Yes, they are 31's but why are you using the diameter?

The calulator I see wants MPH, RPM, Gear, & CIRCUMFERENCE (inches}

Posted By: max_maniac

Re: This can't be right (can it?) - 09/21/11 10:11 PM

I used the numbers you supplied and came up with 5.962%

Russ

Posted By: StrokerAspen

Re: This can't be right (can it?) - 09/21/11 10:13 PM

Quote:

Yes, they are 31's but why are you using the diameter?

The calulator I see wants MPH, RPM, Gear, & CIRCUMFERENCE (inches}

The calculator I am using works off diameter. Basically the calculator I am using takes the diameter, and uses the circumference based on the diameter.

31" X 3.1416 = 97.3896"

I have used this calculator to calculated quite a few cars and it has worked for me. I have had good luck with the Wallace stuff too though.

Posted By: 440Jim

Re: This can't be right (can it?) - 09/21/11 10:34 PM

Quote:

I used the numbers you supplied and came up with 5.962%

Russ

I came up with the same thing using the Wallace Calculator
http://www.wallaceracing.com/converter-slip.php

Posted By: 440Jim

Re: This can't be right (can it?) - 09/21/11 10:36 PM

Quote:

I'm using Wallace Racing Calculator to determine my Conv slip %

Using 132.66 mph/7000 Rpm at the line/ 4:56 gear ratio/ and the advertised roll out of my tires as 97"

I came up with 17.511 %

You are inputing gear ratio with a colon (4:56) instead of the proper way which is a decimal (4.56)

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/21/11 10:41 PM

Now I see what I was doing wrong

I was typing in 4:56 instead of 4.56 and that's what gave me the high slip.

Once I put in 4.56 I got 5.962 %

However, that said, I was starting to think that with the high slip that I was leaving some ET on the table and that a tighter conv would help get it to where it seems everyone thinks it should be running.

Now, I don't know what to think.

How do you know if you have the right (best) conv for your car?

Posted By: StrokerAspen

Re: This can't be right (can it?) - 09/21/11 10:49 PM

I would say 6% isn't too bad. What size is the converter? if it is an 8", maybe you could get a 9" converter built that will still get you off the mark the same.

I would say everything is working well. There is a little simple math problem that gives you an idea.

1320/MPH = Optimum ET.

1320/132.5 = 9.962

An exapmle of one that ISN'T working to its full potential is My car

But that's to be expected with a big loose converter and 3.23 gears.

1320/128 = 10.313..... I have gone 10.68.

Is it a scientific math formula? No, I think it's a fluke that it works. haha. OR maybe it is and I don't know why it works. But it does.

-Kenny

Posted By: Sport440

Re: This can't be right (can it?) - 09/21/11 10:49 PM

Yep as you know you were doing it wrong. Your slip will be just abit higher then that because of tire growth. MT tires will grow about 1" according to MT.

IMO, you your vert is ideal when the 60 fts are inline with the MPH for its ET.

But theres more to it then that. Some verts will have more torque multiplication then others. Most of the Good names should be in the same range of multiplication IMO. But maybe not. Congrats on your 9,s.

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/21/11 11:02 PM

Calculated 60' for that pass was 1.383467

Actual 60' was 1.361

Posted By: VernMotor

Re: This can't be right (can it?) - 09/22/11 12:31 AM

well for me it says I got 8.14% slip. But that 1320/120 says 11.00 we run allot of 11.0s

Posted By: Guitar Jones

Re: This can't be right (can it?) - 09/22/11 02:06 AM

It's all math...and physics, math and physics. Why didn't I pay more attention in school...

Posted By: roadhazard

Re: This can't be right (can it?) - 09/22/11 02:32 AM

I've seen a few of your recent posts Guitar Jones and wonder if we're brothers

I'm going to run mine now & try the "Stroker Aspen Math"

Congrats on that 9 Bill

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/22/11 03:13 AM

Quote:

I've seen a few of your recent posts Guitar Jones and wonder if we're brothers

No need to insult the guy Greg

And thanks

Posted By: Sport440

Re: This can't be right (can it?) - 09/22/11 04:10 AM

Quote:

Calculated 60' for that pass was 1.383467

Actual 60' was 1.361

That 1.361 60 ft. is inline with your et IMO Your MPH is just a touch low, but well withen normal perimeters for your et.

My summary, your 60 ft. and ET and vert slip is well within range.

Your MPH is close to optimum too.

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/22/11 04:20 AM

Doesn't sound like I'll be able to squeeze much more out of it then

On the other hand, that also means I can just put it away for the winter and NOT have to

on it

Posted By: MR_P_BODY

Re: This can't be right (can it?) - 09/22/11 04:24 AM

Quote:

Doesn't sound like I'll be able to squeeze much more out of it then

On the other hand, that also means I can just put it away for the winter and NOT have to on it

Have you tried anything on the tune up Bill... its
real close for the HP to weight(at that given time)

Posted By: WILD BILL

Re: This can't be right (can it?) - 09/22/11 04:42 AM

Aside from jetting it up a bit no.

I was planning on going a little more on the jetting next year to see if I could get the MPH to fall off but that's it.