Topic: Thinking about getting bigger cam??

[H8PVMNT]

So I have another spread sheet wish list.  How about the same cam profiles but in say a carb 20r (2.2) with a header.  I know the head is different and size of combustion chamber etc.

What data do you need to work the spread sheet?

[Gnarly4X]

So I have another spread sheet wish list.  How about the same cam profiles but in say a carb 20r (2.2) with a header.  I know the head is different and size of combustion chamber etc.

What data do you need to work the spread sheet?

I don't think I have any specs on Toy 20R.  LCE is showing the 20R and 22s are the same camshaft.

I could use the stock specs as a base line if I can find them.

bore
stroke
head cc's
carb - single or duel plane
carb CFM
Intake runner length in inches
compression ratio

Tonight I'll see what other data I can use to get more accurate with the output.

Gnarls.

[emsvitil]

Warning................


I'm not sure if all those cams play nice with the 22RE computer.......................

[Gillesdetrail]

Well, I did more "indepth research" and some rough calculations based upon Snowtoy, Gillesdetrail, the others who posted their experience with going to lower gears in the 3rd member - higher gear ratio (4.10 to 4.56 ring & pinion). 

It looks like I was wrong in my thinking. 

YES, it looks like if I swap 4.10s to 4.56s, it will put the RPM at 50, 60, 70, 80 MPH in 4th and 5th gears at a higher torque number  (based on my desktop dyno software) within my usable the RPM range.

 

Gearing is always a great gain for the buck, like its been said, run it that way for now and see how you like it, it may be perfectly adequate for what you want, I just wouldn't expect much more than a stock fresh setup on stock wheels and tire. But if you put in 4.56 or more it'll be a beast I'm sure. I run 4.37 on 31'' and I like it, I would like to run 4.88 gears on 31'' when I'll have a 5th gear.

[Gnarly4X]

Warning................


I'm not sure if all those cams play nice with the 22RE computer.......................

Yes, the selection of a camshaft should be carefully evaluated.  And, the profile specs should be verified with the supplier.  I have found cam specs listed in catalogs and on websites that were wrong or have been changed.

Gnarls.

[Gnarly4X]

Question?

The gear ratio magnification calculation is torque X gear ratio, right?

So if my peak torque is 100 and my R&P in 4.10 my torque multiplied by 4.10 equals 410 lbs.

If I go to 4.56s with same 100 lbs of torque before the 3rd member, my multiplied torque equals 456 lbs.

The difference is 46 lbs of torque increase at the rear wheels when the engine RPM is at it's peak torque of 100 lbs.

Is that correct?

Thanks,

Gnarls.

[blackdiamond]

Question?

The gear ratio magnification calculation is torque X gear ratio, right?

So if my peak torque is 100 and my R&P in 4.10 my torque multiplied by 4.10 equals 410 lbs.

If I go to 4.56s with same 100 lbs of torque before the 3rd member, my multiplied torque equals 456 lbs.

The difference is 46 lbs of torque increase at the rear wheels when the engine RPM is at it's peak torque of 100 lbs.

Is that correct?

Thanks,

Gnarls.

I believe this to be correct. The bigger advantage, of course, is that instead of only improving a select band of the rpm range gearing applies equally across the board.  4.56/4.10=1.11 so you're getting essentially an 11% boost everywhere. Of course, you shift point will change so you low point in torque to the ground will also shift. You should compare the torque curves throughout each gear and consider shift point to get a full comparison.

[emsvitil]

Yep, and tire rolling radius affects the torque too......

[79coyotefrg]

Come'on blackdiamond.... cut me a little slack.  If you are inferring that I'd would pull a 16 trailer at 80 MPH with my truck and that's "crazy", you may be right, but I most likely will just keep the freeway speeds between 70 and 75 and between 60 and 65 on 2 lane and windy hilly roads.  I live in AZ and if you ever get down here and drive on the 17 or 10 freeways on a Friday afternoon during the summer, I assume you'll be shocked when you get blown passed by guys pulling boats, jet skis, travel trailers, 5th wheels, and ATCs when you are going 75 MPH!!l  Is it crazy?  Yeah it can be. So going 80 MPH pulling a trailer where you live may be an oxymoron, but around here it seems to be the S.O.P.!!

MUAHAHAHAHHA  or a 1998 Kenworth W900L with 600 hp and 2200 pounds of torque after leaving Commiefornia and hell bent on making Texas in three hours.

At this point, I'm not even sure this engine and truck will be OK to pull a 16 or17' fiberglass Casita trailer??

I think it will do just fine. as long as Lucy doesnt add a rock from every single place you stop

I've pulled trailers with all 5 of my trucks a good number of times and I'm very aware of the dynamics involved.  In fact, I believe my XtraCab will pull a 16' travel trailer, albeit slowly, I just know that the braking part of controlling it may be dicey, it ain't got the torque of a Dodge diesel.  The weight of the trailer tends to "push" the back end around on the truck on deceleration and braking... and that can be safety issue.

I have pulled a 21' Ski boat on a dual axle tandem trailer with my '85 shortbed 22R, with zero problems, I just didn't  go over 65 MPH, and took extra care to avoid having to brake heavily.

I think you'll pull that ok.

No I mean I dont have an office program on this computer I cant open your spreadsheet.

[79coyotefrg]

I don't think I have any specs on Toy 20R.  LCE is showing the 20R and 22s are the same camshaft.

I could use the stock specs as a base line if I can find them.

bore      88.5
stroke       same as a 22R  89mm
head cc's            about 90cc but it is a hemispherical design
carb - single or duel plane  ditch that get a good 22R carb and adapter or weber
carb CFM                  22R or weber are 325ish
Intake runner length in inches   about 8
compression ratio    about 9 stock but put that head on a early 22r block and SHAZZAAAAMMMM


Tonight I'll see what other data I can use to get more accurate with the output.

Gnarls.

LOL  all you need to know about the 20R is
1. the carbs are very anemic
2. the engines are bullet proof
3. you need a header the stock exhaust is what is called a volumetric restrictor

[Gnarly4X]

...

No I mean I dont have an office program on this computer I cant open your spreadsheet.

OK, I'll convert it to a JPG.

Gnarls.

[Gnarly4X]

UPDATED 8-9:  Excel sheet on R&P Gear Ratio x Tire Size x 4th & 5th Gears, with torque numbers.

I will convert it to a JPG for you know who tomorrow.

These torque numbers are for my rebuild as I see it in my DD.

I only calculated 31" tires and 33" tires, and for 4.10s, 4.56s, and 4.88s, and driving in 4th gear and 5th gear.

The numbers and math clearly confirm what R&P you should consider for maximizing best torque in the RPM range.

That sheet is about 4.5 hours of work on the computer!!

Gnarls.

[emsvitil]

UPDATE:  Excel sheet on R&P Gear Ratio x Tire Size x 4th & 5th Gears, with torque numbers.

I will convert it to a JPG for you know who tomorrow.

These torque numbers are for my rebuild as I see it in my DD.

I only calculated 31" tires and 33" tires, and for 4.10s, 4.56s, and 4.88s, and driving in 4th gear and 5th gear.

The numbers and math clearly confirm what R&P you should consider for maximizing best torque in the RPM range.

That sheet is about 4.5 hours of work on the computer!!

Gnarls.

You need to take into consideration the tire diameter tooo.... (not just R&P X torque)

[emsvitil]

Double check your cells.......   4.88 80mph RPM should not equal 4.56 80mph RPM.................

[blackdiamond]

Spreadsheets are fun. I would calculate the torque in 100 rpm intervals, if possible, and then use those numbers to calculate at torque vs. speed curve using the different tire sizes and diff gears. The best combination is the one with the most area/torque under the curve. You would just want to consider the speed range you're targeting.

[Gnarly4X]

Double check your cells.......   4.88 80mph RPM should not equal 4.56 80mph RPM.................

Thank you.  I fixed it. I was close to dead meat when I was working on the final sheet.

Gnarls.

[Gnarly4X]

You need to take into consideration the tire diameter tooo.... (not just R&P X torque)

emsvitil,

What data are looking for?  Tire size is calculated.  Yes, changing tire size will change the effective final drive ratio.

Example:  4.10s, 28" tires, then swapping tire size to 31", effective gear ratio will then be 3.70:1 - higher geared.

Gnarls.

[Gnarly4X]

Spreadsheets are fun. I would calculate the torque in 100 rpm intervals, if possible, and then use those numbers to calculate at torque vs. speed curve using the different tire sizes and diff gears. The best combination is the one with the most area/torque under the curve. You would just want to consider the speed range you're targeting.

Hey blackdiamond,

Oh yeah... that would be interesting, would you mind jumping right on that?   

I only calculated 50, 60, 70, and 80 MPH because my interest for this exercise is just the torque and power at highway speeds.

Gnarls.

[Gnarly4X]

UPDATE and corrected Excel sheet.

If want to see the change in torque to the rear wheels, you change the R&P, i.e from 4.10 to 3.48 in the sheet, it will change the torque x ratio figure, effectively lowering the torque value.

Gnarls.

[Gnarly4X]

LOL  all you need to know about the 20R is
1. the carbs are very anemic
2. the engines are bullet proof
3. you need a header the stock exhaust is what is called a volumetric restrictor

79coyotefrg,

Thanks for the spec, info, and commentary.

I'll work on this tonight.

I will have to play with converting the Excel sheets into file format that this site will allow to upload.

Gnarls.

[H8PVMNT]

I think putting it up with a 325 cfm carb and a header would be a typical 20r.  The reason I'm interested in this is that my 20r has clearly different and more eager driving characteristics than my 22r. That head is really doing something despite the smaller 2.2 displacement, even bone stock.

I know it's probably not possible to account for the better flow of the head but it would be fun to see what the smaller cubes and square bore/stroke relationship do to the numbers.

[Gnarly4X]

...  The reason I'm interested in this is that my 20r has clearly different and more eager driving characteristics than my 22r. That head is really doing something despite the smaller 2.2 displacement, even bone stock.

So your 20R is eager to be exercised!.... and it feels good when you do it!!??

Gnarls.

Gnarls.

[blackdiamond]

Hey blackdiamond,

Oh yeah... that would be interesting, would you mind jumping right on that?   

I only calculated 50, 60, 70, and 80 MPH because my interest for this exercise is just the torque and power at highway speeds.

Gnarls.

If you can give me a table with the torque curve I just might give it a shot.  I love Excel spreadsheets.  The issue is two small kids and finding time...

[Gnarly4X]

If you can give me a table with the torque curve I just might give it a shot.  I love Excel spreadsheets.  The issue is two small kids and finding time...

Yeah... what engine numbers would you like to see?  The other data is available on a good number of websites with calculators.

Gnarls.

[H8PVMNT]

I am convinced the 20r is better than the 22r as far as drivability goes.  Much more rev happy and feels like a better torque curve all around.  I'm sure it's the head design.

[Gnarly4X]

I am convinced the 20r is better than the 22r as far as drivability goes.  Much more rev happy and feels like a better torque curve all around.  I'm sure it's the head design.

Wow... that's interesting.  It's less CCs?? The head is supposed to be better than the 22s?

Gnarls.

[emsvitil]

A 28" tire @ 4.10 will have about the same effective torque as a 31" @ 4.56 and a 33" @ 4.88

The larger diameter tire negates the higher ratio R&P.

Take a look at 4.88 33" 5th and 4.56 31" 5th RPM.      They are about the same.       The 4.88 torque numbers look better, but really aren't because you lose some torque multiplication due to the larger diameter.

[Gnarly4X]

A 28" tire @ 4.10 will have about the same effective torque as a 31" @ 4.56 and a 33" @ 4.88

The larger diameter tire negates the higher ratio R&P.

Take a look at 4.88 33" 5th and 4.56 31" 5th RPM.      They are about the same.       The 4.88 torque numbers look better, but really aren't because you lose some torque multiplication due to the larger diameter.

Hmmm...  the torque numbers are different because of multiplication.

Gnarls.

[emsvitil]

Hmmm...  the torque numbers are different because of multiplication.

Gnarls.

yes

Changing tire size is like changing R&P...........

[blackdiamond]

Yeah... what engine numbers would you like to see?  The other data is available on a good number of websites with calculators.

Gnarls.

Torque at as many rpms as possible. I think you have the data already. Basically, the data to plot a nice torque curve.