RPMs using R154 and 4.30 LSD diff?

[j_magers]

Has anyone created a matrix/spreadsheet of what the RPM's should read when using a R154 tranny and a 4.30 N/A LSD differential. Also, what the speedo should equate to?

[lagged]

ugh it stinks on the highway. at 3000 im around 64 mph.

[JustAnotherVictim]

ugh it stinks on the highway. at 3000 im around 64 mph.
that's compared to around 80mph at 3000rpm for 3.9 lsd

[Fuzz420]

that's compared to around 80mph at 3000rpm for 3.9 lsd

80mph in my n/a 4.30 lsd=3400ish rpms

[j_magers]

theres gotta be an equation for it, its all numbers (gears), no one has figured this out

[wingman]

80mph in my n/a 4.30 lsd=3400ish rpms


no kidding, glad I'm done with that...I'd drive 30 highway miles on 1/4 tank and 50 city miles on the same amount!

[IJ.]

Stock tires + 154 + 4.30's.

http://members.optushome.com.au/suprapics2/speeds.jpg

[j_magers]

Heres what I found on some website:

Input Parameters Are the Following:
Differential Gear = 4.30 to 1
Transmission Gear = 1.00 to 1
Tire Diameter (Inches) = 36.00
Tire Growth Factor = 0.000100 (Inches/(MPH*MPH))
Transmission Efficiency = 85.0 percent at 3000 RPM
Transmission Efficiency = 95.0 percent at 4500 RPM
Computation Results:
Vehicle Computed Tire Xmisssion
MPH RPM Growth(In) Eff (%)
--------------------------------------------------
30.0 1646 0.09 73.0
35.0 1884 0.12 74.3
40.0 2113 0.16 75.7
45.0 2334 0.20 77.0
50.0 2546 0.25 78.3
55.0 2751 0.30 79.6
60.0 2948 0.36 80.9
65.0 3138 0.42 82.2
70.0 3321 0.49 83.5
75.0 3498 0.56 84.8
80.0 3668 0.64 86.0
85.0 3832 0.72 87.3
90.0 3990 0.81 88.6
95.0 4143 0.90 89.8
100.0 4291 1.00 91.0
105.0 4433 1.10 92.3
110.0 4571 1.21 93.5
115.0 4703 1.32 94.7
120.0 4831 1.44 95.9
125.0 4955 1.56 97.1
130.0 5075 1.69 98.2

So using these numbers your 80mph rpm range is almost right on.

[j_magers]

Ian, what is the R154 gear ratio

[IJ.]

Jay:

1st 3.30

2nd 1.95

3rd 1.34

4th 1.00

5th 0.75

[j_magers]

yea, i knew the gears but this input asked for "Transmission Gear = 1.00 to 1" it defaulted at 1 to 1

[cjsupra90]

Jay, thats the default for the site, just change the first number to the number that Ian posted for the gear (1st thru 5th) that you want to know.

Example
1.34 to 1 for 3rd gear
.75 to 1 for 5th gear
and so on.

Also dont for get to change the tire diameter to what you have form what they have listed

[IJ.]

I posted up the info requested in a table ..... ;)

[CRE]

If you want to think about it while you're driving it's about a 9% difference on the speedo per a given RPM. I swapped my 4.3 for a 3.91... the 4.3 was driving me nuts. I'm starting to think I'd rather have a 3.73 though, but I'm not an "off the line" kind of guy.


BTW, where are you guys getting the speedo sending gear for a R154 and a 4.3 diff? Or are you just calculating your speed on the fly?

[cjsupra90]

If you want to think about it while you're driving it's about a 9% difference on the speedo per a given RPM. I swapped my 4.3 for a 3.91... the 4.3 was driving me nuts. I'm starting to think I'd rather have a 3.73 though, but I'm not an "off the line" kind of guy.


BTW, where are you guys getting the speedo sending gear for a R154 and a 4.3 diff? Or are you just calculating your speed on the fly?

Dont get me wrong here, off the line spunk is nice, but 3000 rpm and higher is too much for highway cruise especially with the price of gas these days. Thats why I am dying to put a T-56 6sp. in my supra although as Ian found out, it doesn't exactly fit. but would make for a great best of both worlds setup using a 4.30 rear gear especially if you used the unit that has the .50 6th insted of the .63, but Ian's 5th cruise rpm's are kinda nice with the .63 5th in his TKO and the TKO is a damn nice tranny as I actually installed a TKO600 about a month ago in a Rustang sorry I mean Mustang for a guy and got to drive it yesterday have had enough miles on it and the clutch now to be able to get on it now and fly through the gears. ooh does that thing shift nice.:squirt-mo

[CRE]

I like my 3.91, but I'd really love to have 5th geared higher..... specifically for highway cruisin'. Anyone know if this can be done on a W58 or a R154? (easily)

[cjsupra90]

I like my 3.91, but I'd really love to have 5th geared higher..... specifically for highway cruisin'. Anyone know if this can be done on a W58 or a R154? (easily)

Being that both gears that make up 5 (main shaft and counter shaft) are removable, it could be done by having custom ones made, but nothing off the shelf or atleast that I am aware of. All toyota tranies that I know of are in the range or .7's and .8's including the 6th gear in the getrag V160's from TT supra's. Thats the bad part about swaping the TT V160's is that they are single overdrive and thats what makes the Tremic T-56's so nice is that the are double overdrive.

I have actually toyed with the idea of a custom 5th gear and might look into possibly persueing it further if there seems to be enough interest. I'm thinking low .6's for the 5th would be a significant differance.

On that note just to make sure that we would not be labering the motor to much if anymore then we already are at highway speeds of lets say somewhere in the neighborhood of 70mph, Ian would be a good test subject here being that he has a TKO installed and has a .63 5th gear and has a pretty damn good tune on his car if not excellent..... Ian, I know that I should probably already know this, (please forgive me if I have forgot) but what rear gear are you using running and could you tell me what type of manifold vacuum numbers you are seeing while at somewhere around in the 115 to 120kph range in 5th gear on level roadways. Also, I am not that vastly educated on running LP, but do you think or know if that would cause a different reading from using gasoline (petrol).

[cjsupra90]

I like my 3.91, but I'd really love to have 5th geared higher..... specifically for highway cruisin'. Anyone know if this can be done on a W58 or a R154? (easily)

Being that both gears that make up 5 (main shaft and counter shaft) are removable, it could be done by having custom ones made, but nothing off the shelf or atleast that I am aware of. All toyota tranies that I know of are in the range or .7's and .8's including the 6th gear in the getrag V160's from TT supra's. Thats the bad part about swaping the TT V160's is that they are single overdrive and thats what makes the Tremic T-56's so nice is that the are double overdrive.

I have actually toyed with the idea of a custom 5th gear and might look into possibly persueing it further if there seems to be enough interest. I'm thinking low .6's for the 5th would be a significant differance.

On that note just to make sure that we would not be laboring the motor to much if anymore then we already are at highway speeds of lets say somewhere in the neighborhood of 70mph, Ian would be a good test subject here being that he has a TKO installed and has a .63 5th gear and has a pretty damn good tune on his car if not excellent..... Ian, I know that I should probably already know this, (please forgive me if I have forgot) but what rear gear are you using running and could you tell me what type of manifold vacuum numbers you are seeing while at somewhere around in the 115 to 120kph range in 5th gear on level roadways. Also, I am not that vastly educated on running LP, but do you think or know if that would cause a different reading from using gasoline (petrol).

[IJ.]

Chris: My TKO is a .68 5th gear unit.

I haven't really paid a lot of attention to the vac readings at cruise as I don't have a gauge so would have to check on the hand controller. (will do next time I drive it)

I run a 4.10 JZA 70 diff in it and nope vacc is vacc it doesn't care what the fuel is it's more a mechanical measurement.

[IJ.]

Here are the numbers on my combination Chris!

http://members.optushome.com.au/suprapics2/speed2.jpg

[lanternman]

Looks like you need to raise your redline to 7550 then IJ.

[IJ.]

LOL it's at 7700 now LM and has been for quite some time!

[cjsupra90]

Ian, sorry I forgot (.68 not .63)....

Anyways, thanks for the info about the use of LP. I figured that it would be the same, but wanted to make sure.

[lanternman]

LOL it's at 7700 now LM and has been for quite some time!

My bad, I just ASSumed because that is where your chart topped out. Either way I like the way it looks, 75mph at under 3k rpm.

[IJ.]

Chris: Always welcome! :)

LM: It cruises so nicely now!

250kph/155mph is like 5800 and it does it so easily!

[jawsgear]

There is a RPM Calculator on our website. You can calculate what RPM's you are turning based off your Ratio, Tire Size, and MPH. www.jawsgear.com