Help applying oil data to ATF choice drag racing

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i am interested in what the numbers actually mean on atf oil data sheets and what differences if any a higher or lower figure actually mean in a real world racing situation (i have listed the specs for comparable valvoline fuchs and castrol products for discussion below)

i am sure the topic of specification comparison is of interest to a lot of people out there who like myself simply dont know what the numbers mean or which ones are important and end up just using atf brand XX (or other fluids) that racer jo uses in his setup because thats what seems to work ok and hasnt had a problem... yet

however with all of the technical information and data sheets etc that is available nowadays i really want to be able to make these choices on an informed basis using actual numbers and specs rather than just going with whats worked kind of ok for racer jo in the past...


applying this directly to my setup... i have a 700hp drag car running a built powerglide with transbrake and manual valvebody the atf im currently running is valvoline dex3 which gets changed at 50 runs or so and comes out nice and clear red, no unusual smells etc.

my trans builder said to use a dex 3 atf from a recognized brand, and not to put synthetic atf in there as it is too slippery and causes problems with band and clutch packs etc



here are three similar dexron 3 products from valvoline castrol and fuchs. the only reason ive picked these three is that i have the information handy and they seem to provide the figures for the same attributes to make an easy comparison...

i realize a lot of people are using full synthetic atf,type 5, tractor oil and other varieties of oil in their transmissions and the type of oil is covered in other threads... so im not asking what i should use instead of dex3...

my questions are :

1* what do the numbers mean or more correctly which are the important ones to consider for a drag car

2* does a slight change in say the kinematic viscosity or the viscosity index as per the figures below mean that one fluid is 'better' than another (ie noticeably or are the three so close it doesnt matter?

3* which of the numbers mean that the atf will perform (noticeably) differently on the drag track either through the day or over time as the atf has done more runs?? (ie as it warms will the car get differing times etc) and how much different (eg the 100c kinematic viscosities are pretty close how much higher or lower would make a noticible difference in the atf performance? is 0.1 a big deal or does it need to be say 1.0 higher to matter etc...


thanks in advance for any education people can offer me
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VALVOLINE DEX3

Viscosity @ 100°C, mm2/s, ASTM D445 7.1
Viscosity @ 40°C, mm2/s, ASTM D445 34.7
Viscosity Index, ASTM D2270 175
Density @ 15°C, kg/L, ASTM D4052 0.857
Pour Point, °C, ASTM D5950 -42
Flash Point (COC), °C, ASTM D92 216

CASTROL ATF DEX III
KV @ 100 0C (cSt) 7.2
KV @ 40 0C 36
cP @ -40 0C 17,600
viscosity index 186
pour point deg c 42.5

FUCHS TITAN ATF 4000
density 15deg c 0.862 g/ml
flash point din iso 190 deg c
pour point din iso -50 deg c
foaming tendency seq ii astm 30/0 ml
kinematic viscosity 40 deg c 37.8 mm2/s
kinematic viscosity 100 deg c 7.6 mm2/s
viscosity index din iso 174
 
Quote:

my trans builder said to use a dex 3 atf from a recognized brand, and not to put synthetic atf in there as it is too slippery and causes problems with band and clutch packs etc
I would guess the builder knows don't overthink it. I am not sure about the slippery part of the syn oil though..
 
Originally Posted By: CT8
Quote:

my trans builder said to use a dex 3 atf from a recognized brand, and not to put synthetic atf in there as it is too slippery and causes problems with band and clutch packs etc
I would guess the builder knows don't overthink it. I am not sure about the slippery part of the syn oil though..


If I'd applied the same "trust the expert" attitude to Taiwanese neurologists, as I was advised to, I'd be dead.

Let him "overthink it" if he want's to. That's what the brain is for.
 
If the trans builder is good he will see his transmissions over a period of time especially in racing applications for refreshing or repair and find out what oil and parts does and doesn't work.
 
Quote:
applying this directly to my setup... i have a 700hp drag car running a built powerglide with transbrake and manual valvebody the atf im currently running is valvoline dex3 which gets changed at 50 runs or so and comes out nice and clear red, no unusual smells etc.


First of all, why would you run a Dexron III in a racing transmission?

If it is properly built for racing, a Type "F" transmission fluid should be used, such as:

http://www.amsoil.com/shop/by-product/tr.../?code=ARTQT-EA

or

http://www.redlineoil.com/product.aspx?pid=52&pcid=9

Quote:
my trans builder said to use a dex 3 atf from a recognized brand, and not to put synthetic atf in there as it is too slippery and causes problems with band and clutch packs etc


That's a bunch of nonsense.

You want a synthetic Type "F" fluid with the following specifications:

Kinematic Viscosity @100C, 7.1 to 10 cST
Kinematic Viscosity @40C 40.0 to 54 cSt
Viscosity Index 140
Viscosity CCS, Cp, 3894 (-30)
Flash Point, (478F)
Fire Point, (504F)
Pour Point, (-60F)
NOACK Volatility, 5%
 
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that is a fair comment however, knowledge is power and being able to identify which atf is a cut above the rest and why is a valuable skill to have.

slightly off topic but also related ~ engine oil is another area where the information per the spect sheets is important to be able to interpret... if you have an oil that works well when warm but drops off in pressure when its slightly above warm knowing what attribute to look for is an extremely valuable tuning tool to have in the tool box as it were...

the three atfs i posted information about are all from reputable manufacturers
the highest kinematic viscosity is 0.5 above the lowest (about 7% higher)
the highest viscosity index is 15 above the lowest ( about 9% higher)
there is also information about density on two and flash points etc

other than assumption and guess work i dont have any idea which of these are the indicators of a better vs an average oil or even if these variances are enough to say that one atf is materially better than the others, or which to choose and why if i want to tune reaction time or 60ft times etc which is my reasoning in looking for this guidance.

my educated guess would be that a higher kinematic velocity would degree be preferable as this seems to be related to the sheer strength of the oil and possibly a lower viscosity index as this seems to relate to how thick it is.. and how much drag the fluid has ie lower drag faster acceleration... but whether either is correct and how much difference in the numbers actually makes a difference i have no concrete idea...

at the end of the day engine oil or even water would do the job for a period of time but just because it does the job doesnt mean its the best choice long term...

the builder said reputable manufacturer but to me that is just a good starting point... they all will do the job but which is going to do it better... remember drag racing is measured in 1000ths of a second and even a small improvement or slightly better consistency can be the difference between a win and loss
 
Molakule, I build quite a few TH400 "Based" 2-speed & 3-speed transmissions for 900-1300 horsepower drag cars a year, And a few Powerglides also. I know from reading your posts....You know a lot more than me about ATF formulations.

I recommend Dex-3 for all the GM racing transmissions I build, With "High" Fixed line pressure & No Accumulation....I don't want the upshifts to be any firmer than they already are by using an ATF with little to no friction modifiers. I spend a lot of time trying to soften initial apply while maintaining clamping force & Dex-3 helps me achieve that.
 
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i have found some tech information on the following which relates to engine oil but the viscosity data will applicable to atf.

discussion kinematic viscosity and viscosity index
http://upmpg.com/tech_articles/motoroil_viscosity/data_bulletin.htm

discussion of oil viscosities in laymans terms (ie 5w30 20w60 etc)
kinematic viscosity (KV) is measured in cst which is the viscosity of the oil or fluid and a reflection of the oils sheer and viscosity at two differing temperatures 40 and 100 deg c. the test involves the time it takes for the flow of a certain volume of oil through an orifice and this is what gives a multigrade oil its weight name ie 5w30 etc. the sae oil weights are based on the kv figures and an sae weight (eg the 5 or 30 in 5w30 ) correlate to a range of cst values, so kv 0-1 = xxx and 2-3 = yyy etc. a cst value of 9.2 is a 20 weight oil and a kv of 9.3 relates to a 30 weight oil. therefore the kv value number is valuable as it allows you to dientify how far inside the weight range of the oil your oil is. if you were having a problem with that 5w30 with a 9.3cst kv oil being too thick and wanted to go to a 5w20 then choosing one with a 9.2 cst kv value would be pointless as its hot kv would be almost the same... (kv can also be thought of as the oils film strength higher = thicker oil, stronger film strength)

the viscosity index is the spread of the two kinematic viscosities relative to one another. a high number indicates that an oil has a lower variance between the 40 and 100 deg c viscosity and a low number means there is a big variance. anything over 100 VI is considered high the rule of thumb in the article is that a high VI is preferable to a low one

AND bob is the oil guy lists this convert the cst into an sae weight

http://www.bobistheoilguy.com/viscosity-charts/

so this seems to answer most of my initial question regarding the kv and vi numbers and how they relate to one another etc.
 
thanks molakule and clinebarger for your comments they are an interesting development to the topic

molakule suggestions re using a type f style of atf are from a strong technical knowledge base

and clinebarger is a transmission builder who builds a number of transmissions and has hands on experience re function (and no doubt internal condition after a teardown etc) and has developed an atf strategy of using dex3 to create a softer upshift in his mid hp cars. the dex3 recommendation being the same as my trans builder recommends for my trans built to take about 1000hp

i have also seen people recommending a 50/50 mix of dex3 type f including here (which lists recommendations based on hp figures)

http://www.rosslertrans.com/RECOMMENDED FLUIDS.html

from clinebarger it seems that in the lower hp levels a less grabby atf like dex 3 is a good choice as a 'softer' upshift is more desirable (possibly to limit wheelspin or protect parts from the shock of a firm upshift?? )

and then as the hp figures increase a firmer shift is needed to efficiently apply the power to the driveshaft which makes a more grabby atf like the amsoil and redline products molakule suggests

i would be really interested in what molakule and clinebargers thoughts are in relation to this.

molakule, do you think that the type f style fluids (or a mix of type f / dex3) are a better choice given the soft upshift preference ? or do you think a lighter weight oil like this from redline would be a good comprimise (they also list powerglides and turbo trans in the list of uses for it..)

http://www.redlineoil.com/product.aspx?pid=137&pcid=9

cheers
 
Originally Posted By: dnkx

from clinebarger it seems that in the lower hp levels a less grabby atf like dex 3 is a good choice as a 'softer' upshift is more desirable (possibly to limit wheelspin or protect parts from the shock of a firm upshift?? )


Those two are Exactly why! Hard part protection is important to me, A overly harsh shift can upset the chassis & induce wheel-spin.....Not fun at half track!

Dex-3 only helps, ATF selection is Not the only component, Friction material, Clutch clearance, And Wave Plates (Or lack of) all play a part.

Friction Material...I use "High Energy" Carbon Graphite frictions that were designed for use with Dex-IIE & later Dex-III. I do not know if High Energy frictions were ever tested with Type-F??? Molakule may have more light too shed on the subject.
Most professionals don't use "Race Frictions" anymore, Like Raybestos "Blues" & Alto "Reds" That are 100% compatible with Dex-3 & Type-F.

I recently refreshed a T-Brake TH400 I built 5 years ago with over 300 passes on it...Right at the 1100 HP mark, The OEM 4L80E Borg Warner High Energy Forward, Intermediate, & Direct Frictions were in good shape....With NO fluid changes, Running generic Dex-3.
 
The line pressure is what dictates the fluid choice, especially with extra steels, omitted wave plates and such to increase the torque capacity.

I haven't ran a TH400 since 1980, but when we did in the old daze we jacked the line pressure so high they would rupture regular hose to our coolers. Ran well, but the only time anything broke it was always traction that caused it. A properly built TH400 is pretty hard to break.

These days good traction is far more reliable with modern tires, so the harsh shift can easily upset the chassis. Seems to make good sense to match the fluid to the setup...
 
Steve, I know it doesn't matter now...But, You have too Limit/Restrict the Converter Charge on fixed line pressure TH400's, That would have corrected your Cooler pressure issue.
 
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