SCCA Enterprises IB 001-2016 Transmission Reliability

Information from SCCA Enterprises to help you keep your car in top shape!
User avatar
Former Specracer National Champion
Former Specracer National Champion
Posts: 87
Joined: Fri Jun 08, 2012 5:42 pm
Location: Denver, Co.
Chassis:
247-1
PostPosted: Wed Apr 27, 2016 5:26 pm
SCCA Enterprises Information Bulletin 001-2016
Transmission Reliability


Lets start with a GEN3 1.6 / GEN2 1.9 comparison.

Both 1.6 / 1.9 are basically the same aero drag, suspension, tire, same basic grip potential, load placed on the gear box is close to the same. 1.2 G is 1.2 G, it really doesn’t matter which engine is providing the torque. The GEN3 weighs less, over-all load on the gear box is same or a touch less.

Both engines for all practical purposes have the same peak torque. How they make torque is different.

Lets draw a line across a dyno graph at peak torque for both engines, they are close, the 1.9 a tick higher. Now draw another line across 5 lb ft, down from peak, this tells the story. When you average the area under the curve, we see the difference. The 1.9 is around 1400 RPM, 1.6 is around 3100 RPM wide 5 down from peak. The GEN3 power band is a little over twice as wide.

Now, depending on how you shift, you can see why a GEN3 will out accelerate a GEN2. It weighs less and has a higher average torque output. We are not talking gross amounts of torque and shift points are the key, but it’s in the range of 1 or 2 lb ft of torque on average run through a gear.
Hmmm So why is the 1.6 so much harder on the transmission or is it ? Surely Mazda / Ford didn’t design the transaxle right on the edge of reliability .

Here are some reasons….

The clutch, The OEM 1.9 clutch can clamp the disc .25 to .4 tenths of a second under power. Tilton Clutch can clamp the disc in about .15 tenths of a second under power. The OEM disc has a dampened hub and the Tilton is solid and less forgiving.

Engine characteristics, the 1.9 is lethargic, the 1.6 is quick and free revving. Most drivers depress the clutch to shift at 6500 rpm…then free rev the 1.6 into the rev limiter around 7000 / 71000 rpm, release the clutch at a higher RPM than needed… more shock to the drivetrain on each up shift.

Wheel Spin, when you drop a wheel at corner exit or jump an apex curb without a lift…the 1.9 at 5300 RPM, torque is around 99 lb ft. The 1.6 at 6100 RPM torque is around 112 lb ft range. The 1.6 maintains torque much higher in the RPM range, wheel spin with your foot on the throttle creates more shock to the drive line when the tire regains traction suddenly.

Harmonic’s, destroyed the original starter solenoids. A dampened clutch disc will reduce this.

Transmission Temp, because of the higher tooth frequency, running temperature is up 15 to 20 Deg.

Transmission Oil, todays additive packages are much different than in the past, we could spend pages on this alone. "I’m going to way over simplify". A lot has changed with OEM’s since 1993, efficiency / long life are top of the list now days. This has pushed OEM’s to design very specific transmissions for many applications, along with very specific oil additive packages for each. This is where the problem starts for Petroleum company’s, retailers and racers….we all want to push the edge of efficiency as racers and Petroleum companies / retailers for profitability. There are more than 70 ATF / Transmission / Differential fluid specifications today. Gone are the days of Type F and Dexron ATF’s and 3 or 4 different gear oil’s in 2 or 3 viscosity’s. This is where the Petroleum companies run into a problem; they don’t want to blend each specific oil spec, retailers don’t want shelf 70 product types, so they cross blend and reduce the number of oil types they produce for the highest profit.

When our transaxle was new, Ford Spec’d 2.6 to 2.8 quarts of “Mercon” ATF and Mazda Spec’d (similar amount)of GL-4 gear oil / viscosity based on average temperatures where you drive the car. It’s important to understand ATF’s have different viscosity’s, even though they are not labeled as such.

You will need to do your own research, but choose the oil type wisely. It will help dissipate heat if you use 2.5 quarts, instead of 2 quarts.

How can SCCA Enterprises help,

The current Tilton clutch configuration we are using is about 60 lb ft less torque capacity or softer than the first 2 configurations. Tilton made a new diaphragm spring and organic disc just for our project, it’s the most forgiving clutch they have available.

For an example the 1.9 OEM clutch has around 145 to 160 lb ft of torque capacity. The current Tilton configuration we use is around 160 to 170 lb ft of torque capacity. We are very close to OEM, the rate it clamps the disc has to do with the design, Racing type vs OEM type.

We are working on a dampened clutch disc. The problem is there is not very much room under the clutch cover for the hub. I hope to have some samples by mid-summer to test.

Alternative gear manufacture, I talked with after-market gear manufactures, because the 3.62 final drive was obsolete. We now use the 3.85 final drive from the current “Mazda 2” we can service the final drive for the foreseeable future. Recently we reopened talks with an alternative gear manufacture to produce more durable 3rd though 5th gear sets at reasonable cost.

How can driver / owner help

Shift carefully and run little more oil in transmission…think about wheel spin and the sudden shock to the drive line when the tire regains traction, either from being bounced in the air or on and off the asphalt.

Keep some notes on the true amount of run time on the gear box / with the type and amount of oil used. Send the data to us…I will not share what you do…but give more of a “people have used a 70 / 30 mix of ATF and Gear lube” with good reliability.

One last note on the pre planning of the GEN3 kit :

The 5 SPD gear box that is paired with this engine, 2011 to current Fiesta was not a good fit for us. Gears are a little thinner (weaker) than our current gear box. Plus the ratio’s spacing is on the short side because of the 4.07 final drive ratio.
We would have also needed frame modification, it uses a cable shifter, which would feel just like a street car…that would have been a positive update. However one of the chassis tubes is in the way of the shifting mechanism on the gear box. We would also need a custom shifter & cables. The OEM ones are too short to reach and the shifter is plastic. Also new custom axles.
I’m not sure of the exact cost, it would have been in the additional 4500 to 5000 dollar range…plus labor for cutting and welding of the new frame mounts. We looked at this when the GEN3 project started rolling. The goal was and is to keep SRF running cost in check as much as possible. I think the gear box needs to reliable for 30 plus race weekends with a test day and that is the current goal.
Fords engine life forecast for the 1.6 is almost 2 times the life of the 1.9. The 1.6 needs conventional motor for 25 / 35 hours to reach peak performance. If you don’t over heat or rev, with proper oil & filter changes plus keep a clean oiled air filter in place. The 1.6 should provide many racing seasons of reliable performance.
In closing, the GEN3 conversion has been reasonably trouble free from the start, new issues do arise when you have 300 examples running across the county… It’s about the ratio of stress and expense vs smiles / good times. In my opinion the GEN3 raised the bar to a level, not many other SCCA classes can achieve.
Last edited by Mike D on Thu Apr 28, 2016 11:27 am, edited 2 times in total.
Mike Davies
SCCA Enterprises

Ready to Write a Book
Ready to Write a Book
Posts: 80
Joined: Thu Jul 25, 2013 10:52 pm
PostPosted: Wed Apr 27, 2016 5:53 pm
Good letter overall, lots of explanations and history.
But totally lacking any actionable recomendations on transmission oil/grease.
How about a suggestion form you, maybe a personal opinion that is not binding or something. I am not a lubrication engineer so I don't know beans about the stuff. IMHO you pointed in 10 different directions, I would like one recomendation.
Thanks for all that you have done and all you do every day for us. I do not mean to complain, without your help my car would still be up on blocks.
Bob K
User avatar
Former Specracer National Champion
Former Specracer National Champion
Posts: 87
Joined: Fri Jun 08, 2012 5:42 pm
Location: Denver, Co.
Chassis:
247-1
PostPosted: Wed Apr 27, 2016 6:28 pm
I understand…some sort of direction, Hypothetically speaking, If I was still racing for points with plans to go to the run offs…I would search out Mercon and or GL-4. They are getting harder and harder to find now days.
Back in Sport Renault days we mixed Dexron and GL-4 in the Renault transaxle with very good efficiently and reliability.
Last edited by Mike D on Thu Apr 28, 2016 11:27 am, edited 1 time in total.
Mike Davies
SCCA Enterprises

Ready to Write a Book
Ready to Write a Book
Posts: 87
Joined: Tue Nov 18, 2014 10:40 pm
Location: LA County
PostPosted: Thu Apr 28, 2016 1:18 am
A couple of comments on trans oil:

1] There's not a "t" in DEXRON. The "t" is often inserted because American English is not used to a syllable ending in X next to another syllable starting with R. A 1960's computer generated the name and must not have been capable enough of detecting the pronunciation problem.

2] Real MERCON fluids are no longer available. The bottle might say something like "meets the qualifications of MERCON", but this does not mean Ford granted a license to sell it as a MERCON fluid. It just means that the company ran a few tests that kind of met the specs of MERCON. Ford claims that MERCON-V is backwards compatible to MERCON transmissions, but it is a lower viscosity.

3] When DEXRON-VI was developed, it was also developed to be backwards compatible for DEXRON-III transmissions (including manuals that require ATF). The new viscosity of DEXRON-VI is a little lower than a new DEXRON-III; however, used DEXRON-VI will be a higher viscosity than a used DEXRON-III due to much higher shear stability of the newer fluid. There's a whole essay to be written here and I'll save you the details, but if you want to know more about it, look up "viscosity modifiers" on the interwebs. The are basically temperature sensitive polymers that can be permanently cleaved when sheared, so once they are cleaved, the fluid permanently thins out.

4] GL-4 is another obsolete specification, but because you never needed a license to sell GL-4 rated fluids, they can still be sold as supposedly "authentic GL-4". Also, because these were never licensed, the quality can vary much more than licensed fluids like MERCON or DEXRON. That doesn't mean a licensed fluid is better (especially in SRF application), it just means they are more consistent brand-to-brand and batch-to-batch.

5] ATFs are the most complicated lubricant used in vehicles today. The research that goes into them is mind boggling and if you want to talk about it more, I'll tell you anything that I'm not sworn to confidentiality about. Having said that, I do not suggest mixing ATF with other fluids. There are compounds in ATF that behave differently at different treat rates. The final blend of ATF has a specific treat rate of these compounds, and if you modify that treat rate, it is possible that the result will have the exact opposite effect. As an example, silicone oil is a common anti-foamant used in ATF, but at very low treat rates. If you leach silicone oil into ATF (like say from an RTV gasket), the silicone oil takes on an opposite role and actually promotes foaming. It is a very fine balance and when that balance is upset, bad things can happen. Not only for foaming, but also anti-wear, anti-corrosion, and anti-oxidation properties.

Sorry to go off on a lecture. But having worked on that end of the automotive business for 15 years, I just want to be sure that people know what they are up against.

Cheers,
Chris

Needs a Life!!!
Needs a Life!!!
Posts: 228
Joined: Wed Dec 28, 2011 6:21 pm
Location: Stillwater, Mn
Chassis:
784
PostPosted: Thu Apr 28, 2016 9:00 am
I know a little about engine oil but nothing about manual transmission oil so I ask this question as a totally uninformed person other than what Chris said above. Why is it that we do not just use a high end straight synthetic transmission gear oil? Is it because of extra drag on the transmission, foaming or because of lubrication properties?

Ready to Write a Book
Ready to Write a Book
Posts: 87
Joined: Tue Nov 18, 2014 10:40 pm
Location: LA County
PostPosted: Fri Apr 29, 2016 12:38 am
Bill Parenteau wrote:I know a little about engine oil but nothing about manual transmission oil so I ask this question as a totally uninformed person other than what Chris said above. Why is it that we do not just use a high end straight synthetic transmission gear oil? Is it because of extra drag on the transmission, foaming or because of lubrication properties?


Bill, I don't know as much about Ford developed transmissions as other companies' transmissions, but the two majors I worked for required specific type of friction for their synchros to function correctly. Usually the base oil (what people call "synthetic") has minimal effect on that type of friction. So if you could find a synthetic that hand the chemical adherence similar to what Mazda/Ford required, it should work just fine. But seeing how these transmissions came out of economy cars, synthetics were probably low on the list for testing due to the cost of them in the 90's.

Having said that, I've run a "race worthy synthetic" type GL-4 fluid in a complete econobox endurance race car and it shifted like butter. I'm tempted to try it in my SRF since it seems that I'm rough on transmissions and might need something different than what I'm using currently.
User avatar
Needs a Life!!!
Needs a Life!!!
Posts: 712
Joined: Wed Nov 30, 2011 1:03 am

Chassis:
828
Facebook Page:
http://www.facebook.com/#!/denny.stripling
PostPosted: Fri Apr 29, 2016 10:46 am
This is anecdotal only but I'd recommend rev-matching when you can as well (see my VIR race video).
My last Gen2 tranny had 11.5 years on it and it purred like a kitten. I rebuilt it just because I was going to the Runoffs (ended up not happening) but who knows how much time it still had on it. I rev-match religiously.
I spoke with a front runner (multiple time national champion in another class and perennial Majors level SRF winner) who told me that he never rev-matches but he also said he never got more than 2 seasons out of a transmission.
Just my .02.
____________
Bay 12, please.

Still Learning to Type
Still Learning to Type
Posts: 41
Joined: Sat Dec 03, 2011 12:59 pm
PostPosted: Fri Apr 29, 2016 5:49 pm
Have my Gen 3 in my garage for the first time and was going to change trans fluid. Read this and have no clue on what is best. I always just used Napa Mercon/Dexron III Should I look at race type fluids since they vary so much What is GL-4 ? Do viscosities vary? Do they all mix just fine? Are these usually stocked on the self and labeled as such. I understand there are no absolute recommendations. I could use just a little guidance as I know nothing about this stuff. Thank you Lee

Ready to Write a Book
Ready to Write a Book
Posts: 87
Joined: Tue Nov 18, 2014 10:40 pm
Location: LA County
PostPosted: Sat Apr 30, 2016 9:19 am
Lee wrote:Have my Gen 3 in my garage for the first time and was going to change trans fluid. Read this and have no clue on what is best. I always just used Napa Mercon/Dexron III Should I look at race type fluids since they vary so much What is GL-4 ? Do viscosities vary? Do they all mix just fine? Are these usually stocked on the self and labeled as such. I understand there are no absolute recommendations. I could use just a little guidance as I know nothing about this stuff. Thank you Lee


Lee, if you are happy with what you have been using, then it probably isn't worth the risk to change. But to answer your questions...

1] Should I look at race type fluids since they vary so much? ... You would have to consider the condition of your transmission, if you want to risk shifting to feel different, if you want to risk durability change (either for better or worse).

2] What is GL-4 ? ... It is an obsolete spec for gear lubricants that do not contain Extreme Pressure (EP) additives. EP additives are what make gear oil smell like sulphur-phosphorous and these are generally not used in manual transmissions because they can attack yellow metal. The EP is in axle lube to protect the hypoid gear surface mostly. MT don't have hypoid gears and some have yellow metal synchros, so it is important to avoid axle lubricants.

3] Viscosities do vary, but not hugely. If a fluid has an SAE viscosity rating on the bottle, it should match that when it is new. Engine oils have minimum viscosities when used, but I'd have to refresh my memory if the same is true for GL-4. ATFs with MERCON/DEXRON licenses today have minimum when used ratings, but back in the old days that was not always true.

4] They will all mix since they are all petroleum solutions.

5] Any NAPA level store should have both ATF and GL-4 fluids. There may not be as many choices as the interewebs offer though.

Hope that helps.

Cheers,
Chris

Return to SCCA Enterprises Technical Bulletins

Who is online

Users browsing this forum: No registered users and 1 guest