So I'm just awaiting approval for a new SS/TC

I did some research and found that GM is doing a power upgrade package for the LNF engine (Solstice/Sky, and HHR SS, and eventually Cobalt SS/TC).

What I wonder is, why are they upgrading the power when the input torque of the F35 transmission is already maxed out by the stock numbers? How can they still offer full powertrain warranty in this case? If the max input is 258, and the supposed input would be about 325 with the stage package....well pretty much what I'm asking is can these tranny's handle that?

I'd assume GM has good engineering working for them, and they probably wouldn't offer warranty on something that would blow up their transmission.

Any thoughts on this?

Thanks!

 

Time for you to go to bed and think about what you are saying!

 

yes they can handle it. I believe GM understands these transmissions can hold 350 torque. Trust me GM wouldn't let you keep your warranty if they thought it wouldn't hold

 

Naw man... We're 260hp already, and if your statement that they'll only hold 258 is true -- all our trannies are going down!!!

Especially since we know that Powertrain Engineers usually implement in excess of maximum design tolerances.

*the above post contains sarcasm, please consume in moderation*

 

It is true. the F35 transmission was originally certified to be reliable up to 350 Netwton-meters of torque. There is roughly 1.36 Nm in 1 ft. lb., so the convertion yields about 258 ft. lb.

Now, I assume in the mean time that GM has done additional testing and found the transmission to be reliable in highter torque numbers than originally. Especially since there are multiple people on this site running 400+whp on stock trannies.



Also, keep in mind, if you wheel hop it or do reverse to 2nd gear burnouts, you still can blow the tranny. GM is going to play the abuse card and you will be S.O.L. This has happened to stock SS/SC's, which are well below the 258 ft.lb. torque limit.

 

The manufacturers look at a number of factors when testing and rating a transaxle. For example, vehicle weight can play a large factor in addition to the engine input torque. They also generally don't test a transaxle and certify it to a significantly higher power levels than what they plan exposing it to in production. As to ratings floating around the internet it's important to remember the history of the F35 and where it came from.

The transaxle dates back to 1984 when Saab had developed and introduced it in their then new 9000 platform. This was before GM owned any part of Saab and Saab has revised and updated it over the years as they increased power in their engines. It saw duty behind the Saab-designed Ecopower (B2xx, etc.) family of engines until the 9-3 was redesigned for '03 and they switched over to an Ecotec-based engine. At that time a new bell housing was developed to allow the F35 to be used behind that engine. Until the 2.8L turbo V6 was introduced in '06 the top of the line engine in the 9-3 Vector (which became the Aero trim level in '04) was a 210hp/221ft-lbs high output Ecotec. The 9-5 on the other hand continued to use the older and more powerful Saab engine. In later 9-5 Aero trim levels the 2.3L B235R engine produces 260 hp and 258 ft-lbs of torque. That's more than likely where you're seeing that number from in relation to the F35.

Some additional points to consider is that the Saab 9-5 can weigh up to 600 pounds more than the Cobalt and higher vehicle mass places a higher load on the transaxle. The 9-5 also has a 20-second overboost feature that raises torque to 273 ft-lbs and in Europe you can buy an aftermarket Hirsch Performance upgrade package through your dealer that raises power to 305 hp and torque to a similar number and the kit retains the factory warranty on the car. So the F35 has already proven itself in those more demanding applications.

The main point to keep in mind is that at one time in the past Saab and GM did their battery of durability testing on the transaxle but they only did it up to a certain input torque. It passed at those levels but that doesn't mean it won't pass at higher torque levels; they just didn't test and certify it any higher. And as we've seen and are now seeing it can apparently handle much higher outputs and still meet GM's durability test parameters.

I'm personally not too worried about how the F35 will hold up behind the GM performance upgrade kits for the LNF. What I do find impressive is the 4T45 automatic in the HHR being rated to hold 310ft-lbs. It's almost guaranteed that it will still be heavily torque managed, but those power levels had previously only been able to be handled by the much larger 4T80 and 4T65HD 4-speeds in GM's front drive automatic transaxle lineup. The 4T40/4T45 family uses a more modern clutch-to-clutch engagement operation than those older transmissions, the shifts are fully solenoid controlled, and it has always looked like a nice design, but if you would have told me in the early part of the decade when they were introduced that it would be seeing duty behind a turbocharged engine pushing north of 300 ft-lb I would have been highly skeptical. The 4T4x GM trans is very similar in overall design to Chrysler's 41TE family (which evolved from their Ultradrive/A604) and that transaxle is one of the main reasons the PT Cruiser GT turbo never got the Mopar Performance Stage 2 and 3 kits that the Neon SRT-4s with the same engine got. The new GM-Ford co-developed 6-speed slushboxes should have a better chance at seeing duty in high output applications but it's pretty impressive the old 4T45 can take the beating.

 

Thanks for the disertation on transmissions. REALLY! It's nice to hear some one with real knowledge on a subject a lot of shadetree guys THINK they know all about. My own experience with my LS1 powered 88 Pontiac Fiero, with the original 5 speed that was used behind the High Performance ??? V6, proves the under rating practices from the manufacturers. I only wish the stock axle shafts were under rated the same amount so I wouldn't have to have a custom set made to the tune of $900.

And again. Thanks for the education.

 

The Getrag-designed/licensed and Muncie-built 5-speed HM282 transaxle used in the last couple years of the Fiero behind the V6 as well as behind other 60° V6 and Quad 4 engines up into the '90s was a pretty tough transaxle but still had issues, especially if you tried to do an engine swap and use a high mileage one. With proper maintenance and ensuring a few things like a couple of the internal bearing tolerances are in check they'll last for quite a while in a Fiero with a small block V8 or S/C 3800 swap. Put big giant sticky tires on the rear and you'll either break axles or the trans itself. There's a limit as to what you can expect but in general they can be pushed pretty far.

The same thing applies to the F35 in the Cobalt and HHR. In the early years it didn't always have the best reputation in the Saabs. People would crank up the boost and their higher mileage trans wouldn't take it for long. But Saab has been refining them over the years (it has now been around in it's basic form for over a quarter century) and is even stronger and more refined than when it was first introduced. If you have a new one in a SS Turbo and keep up on maintenance and don't abuse it (clutch dumps on racing slicks, physically hammering every gear changes, etc.) it will probably take quite a bit more input torque.

GM and Saab are apparently comfortable enough with it's strength and that there isn't a significant decrease in service life that they already maintain powertrain warranty up to the 300 ft-lbs mark in a much heavier car. And you can probably push it even further than that but with the possibility service life of certain internal components might be reduced. The LNF cars are young and those types of problems probably won't show for some time, but when and if they do appear it's more than likely going to be first seen on cars that were hammered hard and pushed to the limits and have racked up a bunch of abusive miles.

There will always be some stock power cars that will have manufacturing defects or failures and some heavily modified cars that will never have issues but realize those are two different things. Basically there will be problems beyond your control in some cars no matter if they're stock or modified, some cars that will be modified and never have any issues, and those that are modified and do have trouble. You can't control the first one (i.e. manufacturing defects) but you can have an effect on the last couple. You have the option to turn up the power but even more important in preventing those types of failures is how you treat the trans.

 

Good info! Thanks for the posts blackbird.

On an unrelated note, do you currently own all the cars in your sig. (if so...yikes!) or is that a montage of previous vehicles as well?

 

Keep in mind guys the torque ratings from the factory are not "your transmission will blow up at ___" ratings. They are "the transmission may not be able to tolerate abuse as long after ____"

 

That is a very nice write up....!

 

No problem. And yes, that should be a current list and has grown "slightly" over the years. I'll probably be thinning down the fleet pretty soon but I've also been saying that for years.


Exactly. Although some transmissions are not as tolerant of big power increases, manufacturers generally will not use a component like a trans that's rated at the ragged edge of it's limits if it may have an increased chance of failure. There's usually some headroom left in the design to help ensure reliable service and even when pushed beyond that it may not immediately fail but just wear out faster or be more susceptible to damage from abuse.

I'm not sure what Saab's exact durability testing was but the F35 has more than likely been tested in accordance with normal industry standards for modern powertrain components. That means they hammered on them for probably 150k-200k miles to ensure they can handle the torque level it does with only xx (a small percentage) of failures, excessive wear, etc. If you decide to install a giant turbo on the car and double the input torque certain parts might fail in short order or some might have their service life reduced to 50k or 100k miles, but that's something GM is not going to be able to tell us. The only way we'll find that out is to document what private owners and race teams experience in real-world use and analyze failures to see what the weak spots are and address them.

Racing and modifying your car for increased power is expensive and that's one of the prices you'll have to pay (e.g. possible shorter service life). For those looking at the GM upgrade kits with no other heavy modifications I wouldn't worry about the trans too much if you aren't beating the heck of it. A small number will have problems but that's what the powertrain warranty is for. If the F35 couldn't handle the upcoming power levels with an acceptably low failure/warranty rate you can bet this would have ended up being an "off road use only" upgrade with no warranty retained once installed.

 

Thanks for the Fiero info Blackbeard. I have done a little reading on the trans so I knew most of what you were saying. But here's a question for you. You are obviously in the automotive game and involved in racing so maybe you can give some insight into my question. A year or so ago I found some BRAND NEW Getrag 5 speeds that I was told were used in Europe in the Pontiac van that was produced there. It is supposed to have the lower gear as was used in the Quad 4. I bought one, swapped over the bell housings and now have a stump puller in low gear. My question. Do you think this trans will hold up any better than the higher ratio unit. It obviously has to shifted into second much sooner but I assumed the lower ratio would be easier on the axles. I have already bought high performance axles custom made by The Drive Shaft Shop. What is your opinion on my theory? I am running 235 drag radials but am seriously condidering going to a smaller, sticky, street tire to be on the safe side.

Thanks again for your in depth and intelligent discussion on an important part of a competition car part.

By the way. Which bearings are you describing in the trans? I already have auxilliary bearings pressed into the axle shaft outputs.

Thanks.

 

Yep, I know which transaxle you're talking about. He had a few up for auction again recently and was down to $99 plus shipping and I'm probably going to pick up one of them for my Achieva. At that price, even if I used the guts for parts it would be worth it to rebuild a different ratio one. If that's what you're using it's essentially a brand new trans and there really isn't much you need to or can do to upgrade it. The bearing wear affects some of the higher mileage used ones and allows the differential to move around but that won't be a concern for you.

Speaking of which, the stock open diff is probably the next weak link in the 282, especially if you do any drag racing and high rpm clutch dumps on racing slicks. The powertrain in my Achieva SCX came from one of the former World Challenge cars and has the rare Torsen limited slip which is a helical gear, torque biasing diff like the Quaife. It's been a while since I've torn into any of the 282 transaxles and I'm not sure if there have been any recent developments over the last couple years but I think some of the Phantom Grip style "limited slip" inserts are one of the only options. They put a bunch of preload on the stock spider gears in the factory diff causing it to act somewhat like a limited slip but they also increase wear on the diff and aren't as strong as a true LSD. You might want to look into and see if any other limited slip diffs are now available.

As for the gearing and holding up better, I'm not sure but would guess if you had two brand new transaxles, one with the higher gearing and one with the lower gearing they'd be about the same in reliability. For the actual speed gears and individual gear ratios along with the final drive, the gearing does have an affect on torque multiplication and is much more pronounced in the lower gears. I'd have to pull up the ratios but I thought the trans you're using also has a lower first and second gear ratio but it's probably not going to make too much of a difference. If anything, if you had a turbocharged engine where more load on the engine from taller gearing would allow the engine to build more boost in the lower gears could potentially make a difference, but with a naturally aspirated V8 torque output should be fairly constant.

The drag radial size you're running isn't super wide so I don't think you'll have any major issues running them. If you were trying to run something like a 255 or 275 I'd be a little worried, but if you don't abuse the car from every stop light and dump the clutch they should work fine. A set of ultra high performance street tires might slip a little easier and act as a "fuse" or weak link, so to speak, but your driving style is what's going to have the biggest impact on how it holds up. Be smooth on the throttle and clutch and roll into the power and it should hold up fine.

 

Good info. The guy I bought my trans from is in Marrieta, GA. He also makes up a LSD that I had him install for me when I picked up the trans. I also have two other Getrag V6 trans. One with a Gr8Grip LSD. The same as you describe aftermarket. The other trans will be used for parts although it is complete and was supposed to have only 30,000 miles out of a Beretta. You're right about the Quad 4 ratios. 1st and 2nd are lower than the V6 units. One of these days, when I find enough courage, I'm going to try a 2nd gear start. I'm getting pretty good at the Fiero cradle R&R.

You say he's asking NINETY NINE DOLLARS fot the trans.? I see a trip to Marrieta, GA. in my future. The V6 transmissions are getting harder and harder to find. Having another new trans. in stock sounds good.

As soon as I learned about the Thorsen diff. I went hunting for one. Going so far as to contact Thorsen directly. Take care of your differential. There are zero left to be had. ANYWHERE!

I guess I better get off this thread before I get kicked off. I'm only a little off topic. But thanks for sharing your knowledge. As I said in an earlier post, it's refreshing to talk with some one with REAL knowledge. I, personally, learn something new every day.

 

I'll write a short post to break up the 10,000 word essays above.

 

for awhile i was thinkin that this thread should be deleted but thanks to blackbird its in good shape

 

Blackbird.

You may regret ever answering my first post.

So many of the guys on this forum are installing Cold Air Inlets and intercooler plumbing. The goal is to increase air flow into and out of the engine, as well as cooling the inlet air.

First. Wouldn't it be beneficial to wrap the CAI and IC plumbing with some sort of insulating wrap? The whole idea of spending hundreds of $ on these after market parts is to cool the intake charge. Most of these parts are painted (powder coated) in pretty colors which is great for the asthetic's but not for performance.

Also. I have always been under the impression that HOT exhaust moves faster down the exhaust system than cold air. I can't remember where I heard or maybe read this. If this is true wouldn't wraping the exhaust with an insulating material help in this area also.

Thoughts???
,

 

I would be very surprised if wrapping the intake/exhaust in the heat tape would make a noticeable (or even a measurable) difference. Maybe it would, but more than likely I'd bet that it wouldn't do anything for you on a normal street car.

I've heard that most exhaust tapes trap a lot of moisture, which will cause exhaust components to oxidize and rust a lot faster. So that's something to consider as well.

In my opinion, it wouldn't be worth it.

 

yeah no thanks. Plus it looks like booty

 

Instead of going too far off on a tangent since this was intially about the F35 I stated a new thread here to talk about some of those questions.

 

I am stunned at the amount of knowledge I've just tried to absorb in these two pages. Blackbird... wow. I am in complete awe.

 

my head hurts. I feel like i am back in college

 

What, you got drunk last night too? lol j/k

 

lol thats pretty much all what college was....................... getting drunk