How much power can stock drivetrain take?

**RyanJM** · 08-03-2010, 06:40 PM

I am on my 3rd set of gears. Killed the stock 3.23's with just a CAI, WS6 intake and some pulleys. Then the second set when in with the full exhaust and tune. They started whining after a while now I redid the whole suspension and Motive 3.73's and have to say they have held up good so far and I drive hard. It dynoed 339 with the old tune it's got about 345rwhp or so now haven't got it re dynoyed yet. Now I also have the tranny retuned and it shifts at 6k rpm and the BFG Nt's are pretty sticky tires. it will go soon since the cam and stall are going in Sept.

**thomasterrible** · 08-04-2010, 04:20 PM

No I am not dumping on people for giving their opinions I have one too. I also was not thinking someone personally had a list but rather may have a link to this information. It has happened before. Of course there are going to be variables in how one drives a car and how they maintain it etc, as well as if you are going to use slicks and build a drag car it will require a different approach that what I am interested in doing.

If I knew where to obtain these statistics I would not ask, thats all.

Of course there are companies that offer built rear ends like anything else, or one can go old school and get a Ford 9 inch which is going to take a lot of power, but I am trying to engineer this car and do or do not do modifications after I determine the final cost of beefing up what may be necessary for my application.

The transmission is one thing, even in the description it tell you it is an automatic 4 speed that is longitude mounted and has a rating of 60 ft.lbs. of torque. An obvious easy upgrade to that tranny would be to essentially make it a "65".

I have made fun of nobody in any of my threads, they also usually go way off topic and that is fine with me. There have only been a couple really stupid posts that I have just ignored, but only 2 out of all the hundreds of posts to the several threads I have started so that is pretty good.

Like I said GM has the figures but I dont think I will be able to obtain them, but there is usually a secondary source for everything and I have found them before.

I have a friend that builds expensive motors (balanced, blueprinted etc.) but will not think out the entire project (though he is more than capable of doing so) and then skimp on certain things and then they break and he goes through multiple same parts and has several cars none of which are ever in a reliable state of driving if at all. This is not the approach I am desiring.

It is my chosen daily driver, would like to bump the power in a way I have done before and enjoyed, but first need to figure out what I need to do so as not to have an expensive paper weight in the driveway. My build style for this car is also not that of a drag car which is an important difference that needs to be considered.

There are other production cars out there like the vettes that have had similar power and one can see what they did with those as one general way to see what was needed. I will probably end up having to call in my transmission guy and my race guy to figure out what needs to be done before I start spending gobs of money.

**35th-ANV-SS** · 08-05-2010, 03:25 PM

I know this doesn't answer your question, but I came across it so I thought I would share anyway. So here goes...

http://www.ls1.com/forums/showthread.php?t=17424&page=3

**goof4080** · 08-05-2010, 04:21 PM

Originally Posted by 35th-ANV-SS

There are people on this forum that drive spirited with a stock engine on the street only and have gone through multiple 10 bolts. Some have been M6 cars, others have been A4 cars.

There are also people on this forum who have boosted applications pushing north of 500rwhp and cutting 1.5X 60' times and the stock 10 bolt has survived.

I don't see how a horsepower rating is even valid based on that information personally.

This^^^

**Smittro** · 08-05-2010, 04:50 PM

Stock 10 bolt is maxed out with a 3800 infront of it..imho

**travs98ls1** · 08-05-2010, 08:54 PM

Originally Posted by c5z28

As much as it takes to break it.

you know that guy isn't the brightest crayon in the box

**Smittro** · 08-05-2010, 10:47 PM

**Pauly** · 08-05-2010, 11:11 PM

M30 4L60E has a torque rating of 360 lb/ft engine torque with a max gearbox rating of 610 lb/ft torque
M32 4L65E has a torque rating of 380 lb/ft engine torque with a max gearbox rating of 670 lb/ft torque

M30 Vette version has maximim shift rpm of 6100, others is 5600rpm
M32 max shift rpm of 5600rpm
MAx gross combined weight is 8600 lbs

4l60/65e weights vary from 163-197 lbs depending on torque converter and application

M70 4L70E has a torque rating of 400 lb/ft

M30 converter size 245mm, 280mm, 298mm & 300mm
M32 converter size 300mm
(Diameter of torque converter turbine)

For comparision
4L80E RPO MT1 is rated at 440 lb/ft engine torque, gearbox torque rating of 885 lb/ft torque
4L85E RPOMN8 is rated at 460 lb/ft torque
MT1 weighs 254 lbs
MN8 weighs 255 lbs
up to 21,000 lbs Maximum Gross Combined Vehicle Weight
Max shift speed of 5200rpm
310mm torque converter (Diameter of torque converter turbine)

In the automatic transmissions torque ratings, I assume the gearbox torque is higher because the torque converter is multiplying engine torque before it interes the transmission itself. Most stock OEM TC's have an STR of 1.8. So it if the engine torque rating of the trans is 400 lb/ft and you multiply 380 lb/ft by 1.8 you get 688 lb/ft torque lb/ft at the transmissions input shaft which is pretty close to the gearbox torque rating of the M32 4L65E trans.

T-56 has a torque rating of 450 lb/ft for 94-02 F-body units, 93 was rated at less.
T-56 RPO M12 in the GTO 6.0 was rated at 400 lb/ft with a max. validated vehicle weight of 4000 lbs. M12 in the CTSV was rated at 400 lb/ft engine torque with a max validated vehicle weight of 4605 lbs. The T56 weighed 121 lbs in teh GTO and in teh CTSV weighed 135 lbs.
2000 T-56 RPOM12 in a 2003 Vette was rated at 400 lb/ft engine torque with a max validated vehicle weight of 3696 lbs and weighs 121 lbs.

peace
PAuly

**thomasterrible** · 08-05-2010, 11:31 PM

Where did you get this information? It sounds about right, at least the ones that I am familiar with.

Do you have any similar specs on the 10 bolt?

I do realize I am going to have to beef things up before adding more power and I am interested in what parts to upgrade for a given Hp/Tq amount I can estimate from the engine modifications.

Thanks for the information.

**LSCyaL8R** · 08-09-2010, 03:55 PM

pauly's post was amazing. i never knew the T-56 was that beefy stock. 450 sounds about right for me... for now. I have spent all my mod money on suspension since getting my car. springs shocks, SFC's, STB, LCA's, reloc brackets, end links, drag bags etc. i've begun beefing up the driveline with solid motor mounts, monster stage 3 clutch, tick adjustable master cylinder, poly trans mount. My next mods will be the driveshaft(with loop naturally), rear end, torque arm and a watts link.

Only then will i even consider making more power. In fact I might even wait till I get a new t-56, a k-member and upper and lower control arms and sway bars.

Power is nothing without control. I already have sticky ultra high performance g-force sports on there. I figure i'm about 10k away from being ready for power

**thomasterrible** · 08-09-2010, 04:18 PM

That was quite a bit of information. I have the A4. I too am going to beef up the drive train before adding more power, the other alternative is to break the stock stuff and have it become worthless and the car being towed home to sit.

I have found some articles on beefing up the 10 bolt with 8.5 inch gear sets but they were not specifically for the 4th gen F bodies.

I am currently looking at the Strange 12 bolt option. I have some time to continue weighing my options while saving up to afford them. I have found the Ford 9 inch to usually be the least expensive option to increased strength but I think that the 12 bolt would have better clearance for my application.

It is going to cost money for sure so I am going to continue to research my options. The measure twice cut once sort of thinking. I am not trying to build a drag car just a competent street machine with a bit more power than the car has stock right now. Probably could be considered a sleeper when done since I plan to keep things looking stock, I like the way it looks stock anyway. I like a lot of things about the car, if Pontiac had built the car with more than just enough to barely not break stock it would have made increased power a whole lot cheaper.

**Cutlass** · 08-09-2010, 06:02 PM

Originally Posted by thomasterrible

I have found some articles on beefing up the 10 bolt with 8.5 inch gear sets but they were not specifically for the 4th gen F bodies.

Thats not possible. The 8.5" gear sets won't fit in the 7.5" housing. If GM would have given us the 8.5" 10 bolt housing, then we all be happily running 11s and maybe some 10s without much fear.

**thomasterrible** · 08-09-2010, 06:53 PM

Maybe I misread the article but what I was referring to was one by Chevy High Performance Magazine Feb 2009 article titled "How to build a bullet proof Posi 10 Bolt for 400.00 or less" The article was referring to a different year 10 bolt than the 4th gen but that is what it said. Perhaps you can make more sense of it than I did. I dont know much about 10 bolt rear ends since I have never sought out to get one, it just happened to come with the car. This was upgrading the entire rear end to a different year 8.5 inch 10 bolt to be clear, not suggesting that can be done with the 10 bolt in the 4th gen as I qualified.

The Strange rear end direct fit 12 bolt option I mentioned was obviously a whole lot more money than that of course but if I could afford it a nice upgrade.

**thomasterrible** · 08-09-2010, 07:15 PM

As I mentioned this article was not referring to retrofitting a 4th gen Fbody, but would the 8.5 inch 10 bolts the article refers to fit in to one? That does seem like a value priced swap IF it would work

**pajeff02** · 08-10-2010, 04:43 AM

GMHTP built up a 10 bolt in a recent issue -- probably a complete waste of time and money. Swapping in an 8.5" rear could be done, but I am not sure how you accomodate the torque arm mount on the housing without lots of fabrication. There may also be traction control and ABS issues to deal with if that applies. Best bet is to go with an aftermarket rear designed to fit our cars -- lots to choose from in the $2,000 to $3,000 price range.

**Cutlass** · 08-10-2010, 05:28 PM

Originally Posted by thomasterrible

This was upgrading the entire rear end to a different year 8.5 inch 10 bolt to be clear, not suggesting that can be done with the 10 bolt in the 4th gen as I qualified.

aaa...gotcha. I misread your post.

**travs98ls1** · 08-17-2010, 05:12 PM

Originally Posted by Cutlass

aaa...gotcha. I misread your post.

**Y2KPewterSS** · 08-17-2010, 06:55 PM

Originally Posted by travs98ls1

Have a seat in the corner.

**thomasterrible** · 08-18-2010, 06:28 PM

Originally Posted by pajeff02

GMHTP built up a 10 bolt in a recent issue -- probably a complete waste of time and money. Swapping in an 8.5" rear could be done, but I am not sure how you accomodate the torque arm mount on the housing without lots of fabrication. There may also be traction control and ABS issues to deal with if that applies. Best bet is to go with an aftermarket rear designed to fit our cars -- lots to choose from in the $2,000 to $3,000 price range.

I have come to that conclusion, going with the 12 bolt I mentioned, that will also use lower gears so I will see how it feels as well as getting something strong in there.

That article about swapping the 8.5 inch 10 bolt was using old camaros and novas as their applications as well as a race car running a spool and certainly was not taking in to account the torque arm mounting or ABS or anything else so it really is not a good choice for my 4th gen car.

With the 12 bolt I am looking at, which is in the price range mentioned of 2-3 grand you get a just about ready to bolt in rear with the gears of your choice, set up for the stock ABS brakes plus new axles and Posi unit, as far as I can tell it will require welding new LCA mounts on, but otherwise set up to go. That is what I am saving up for and think it is worth the money.