: 700RWHP, can the tranny take it......



SlvrBullIT
07-07-09, 06:10 AM
Wondering if the auto can take the mods to get to 700RWHP, 600+RWTQ? :bouncy:

Razorecko
07-07-09, 10:47 AM
I wouldn't expect it to. At that power level on the auto you should ATLEAST get a good transmission cooler like a Setrab.

neuronbob
07-07-09, 11:28 AM
Off topic, but Slvr, I am ROFL at your signature. Too funny!

Gotham CTS-V
07-07-09, 12:04 PM
Only one way to find out lol...DO IT!

SlvrBullIT
07-07-09, 07:52 PM
Off topic, but Slvr, I am ROFL at your signature. Too funny!

:thumbsup:
I had the quote stuck in my head after watching the CTS-V vs. M5 video where they are talking smack..."smells like victory...."
So I looked up the full quote and had a ephiphany........ Oh yes...the quote needs a "MOD".... hence my signature was born.:bouncy:

SlvrBullIT
07-07-09, 08:53 PM
Was looking at Hennessey and Lingenfelter mods and they never specifically said "manual" transmission only so I'm curious.

V-Eight
07-08-09, 12:34 AM
^ I think with those guys manual is a given..........

Razorecko
07-08-09, 01:14 AM
^ yep. Think about it. Is it better to do the mods on a manual V and post higher gains or do it on an auto V and post lower gains ?

SlvrBullIT
07-08-09, 04:06 AM
Not really looking for "manual is a given" or "Think about it. Is it better to do the mods on a manual V and post higher gains or do it on an auto V and post lower gains ?" -----huh????

I was wondering if the auto trans could take mods or not. Would be disappointed if they put a weak @$$ auto tranny that can get a 3.9 sec 0-60 but can't take mods.....

Razorecko
07-08-09, 10:18 AM
Well the limit of the auto is probaly around the limit of the clutch so after a certain point both will need upgrades

Gotham CTS-V
07-08-09, 04:06 PM
At 700rwhp, a lot of things will need to be upgraded. Cooling, axles, tires, fueling, etc. Tranny would probably be one of those things. 700rwhp in a stock auto tranny is a lot, so I wouldn't be upset with GM if the limit was in the 650ish rwhp range. My friend's B5 Audi S4's auto tranny was having issues with just 350whp! The automatic trannies on Mercedes and Porsches are maxed out at about 700 crank lbs of torque I believe. The 65 AMG series cars were detuned because the transmission couldn't handle the torque that they are truly capable of. When people started tuning them, some folks had their cars get shut down in "limp mode."

Is the 6 speed Auto in our V's the same as the ones found in the Vettes? If so, I'm sure there are some twin turbo C6 Autos that have gotten over 700rwhp. That would probably answer your question.

SlvrBullIT
07-09-09, 01:48 AM
I guess the better questions is, can a auto tranny take a CAI, Pully mods, headers, exhaust, tune

ChipC
07-09-09, 01:49 AM
Is the 6 speed Auto in our V's the same as the ones found in the Vettes? If so, I'm sure there are some twin turbo C6 Autos that have gotten over 700rwhp. That would probably answer your question.

No, it is the 6L90 which is actually a step above the C6 auto tranny (6L80) in torque capacity (6L90 is rated for 111 lb/ft more engine torque over the 6L80). Now, I'm not sure how much modding it could withstand stock, but it looks as though it is as well prepared as any auto tranny GM could offer.

Chip

SlvrBullIT
07-09-09, 06:08 AM
Can't seem to find any "specs" to see what it can take other that the "beefing up" they did to it.

Gary Wells
07-09-09, 07:09 AM
I would be very surprised if the tranny holds up to 700 RWHP and it's comparable RWTQ figure, which I think would be somewhat higher than 600, for anything longer than a dozen or so passes. For Cadillac to even offer a auto behind a 556 HP car is amazing in itself. I don't think that an auto is available in the ZO6, the ZR1, and probably not in any American car other than a few of the big # trucks. We're very fortunate to have this car in an auto.

Gotham CTS-V
07-09-09, 01:11 PM
No, it is the 6L90 which is actually a step above the C6 auto tranny (6L80) in torque capacity (6L90 is rated for 111 lb/ft more engine torque over the 6L80). Now, I'm not sure how much modding it could withstand stock, but it looks as though it is as well prepared as any auto tranny GM could offer.

Chip

Thanks for sharing this very nice piece of info. Sounds like we're good to go!

undertaker
07-09-09, 03:37 PM
I'm going to guess no way in hell as is.

and given the trannies are newer designs without a heavily researched aftermarket for upgrades at the moment, your options on upgrades are severely limited.

does anyone here even have an inkling of how often stuff breaks when you get to 700rwhp setups??

my old vette was 710/640 at the wheels and ate more transmissions clutches and differentials than you can imagine, my current one is over 800/710, and I've smoked every piece of driveline within 1500 miles. Its only going to be worse in a heavier platform of a cts-V (yes sticks but there's still some parallels between them)

I can tell you one thing, I wouldn't want to be the first one trying it.

SRT8/BMW
07-09-09, 03:49 PM
I have no idea. I do know--I had my V tuned by a local guy with a great rep for tuning the vettes. I LOVE the tune..shifts like a race car now. In normal "drive" now it shifts like it used to in sport.

In sport--if you nail it from a low roll (10-60) its wicked shot to the tranny--you can hear it and feel it.

The car is definitely faster--lower temp fans on, higher rpm shifts..etc. But there is no doubt the tranny will take a LOT more stress. I doubt I would want to push it much further. thats just me...:thehand:

ChipC
07-09-09, 07:32 PM
Can't seem to find any "specs" to see what it can take other that the "beefing up" they did to it.

You can go to GM's Powertrain website to view the tranny specs. I would post a link, but I do not have enough posts to do so.

The only other use for the 6L90 is in GM's Heavy Duty truck line.

Chip

chris1268
07-10-09, 01:11 PM
Be warry of the axle joints....Just had mine in the dealer this morning and they had to order me an entire new rear axle, the axle joint is going. Guess I'll be driving a bit slower for the next few days.

Razorecko
07-10-09, 01:23 PM
Be warry of the axle joints....Just had mine in the dealer this morning and they had to order me an entire new rear axle, the axle joint is going. Guess I'll be driving a bit slower for the next few days.

Ouch- how did you know it was going out ? What kind of mods / mileage do you have ? something to keep an definite eye out on

chris1268
07-10-09, 01:35 PM
Ouch- how did you know it was going out ? What kind of mods / mileage do you have ? something to keep an definite eye out on

I started hearing a clicking noise coming from the back of the car about a week ago. Sounded very similar actually to the clicking noise from the front wheels when that happened. It was only happening when engaging a gear or speeding up or slowing down so I had a pretty good idea of what it was already - confirmed by the dealer. Sure didn't take them long to find it. 7,000 miles. Only minor mods to date. I do drive fairly aggressively but I can only image what another 100RWHP would do :tisk:

Razorecko
07-10-09, 03:03 PM
I started hearing a clicking noise coming from the back of the car about a week ago. Sounded very similar actually to the clicking noise from the front wheels when that happened. It was only happening when engaging a gear or speeding up or slowing down so I had a pretty good idea of what it was already - confirmed by the dealer. Sure didn't take them long to find it. 7,000 miles. Only minor mods to date. I do drive fairly aggressively but I can only image what another 100RWHP would do :tisk:

yea people seem to forget that all that hp on a heavy vehicle like the v is stressfull. My dream last night was to drop the lsa into a rx-7 2nd gen.....that would be an easy 9's street car

luvmyctsv
10-05-11, 03:43 PM
I work for GM & I own a CTS-V Coupe with an auto, wife also drives it which is wht the auto. I wanted to something similar so I started to ask a lot of questions. The GM Perfomance Group advises against it. It is not hp but torque that you need to worry about. The 6L90 upper limit is approximately 600 pound-feet. The Performance Group suggested contacting several perfomance shops in the Detroit area which I did, Thompson Automotive and Martin Racing in particular. These are top shelf shops. They actually do development work for GM. Thompson Automotive strongly advised against it modification. Thompson built a Soltice with an 800chp motor connected to a 6L90. They replaced trannies about every 4 weeks. The best GM transmision designers tried custom clutch packs and other enhancements. Nothing worked. I have also talked to some of the GM transmission experts. They all say the same thing, the 6L90 is pretty much near the design limit in a V.

There are a lot of shade tree mechanics out there who will tell you what you want to hear. Just remember they want your money. Unless you can get a rock solid guarantee, I would not advise modifying a V with an auto but its your money. You also need to consider the rest of the drive train as well, not just the transmission. Lastly the LSA is an aluminum block. Increasing boost increases compression. The GM Performance guys stated that could lead to stretching the head bolts and blown head gaskets. Your solution is to sell the auto V and buy a stick V, then replace the LSA block with an LSX block.

My solution is to buy a second CTS-V Coupe with a manual transmission. I have a half a shot at beefing up the balance of the drive train. I also will replace the LSA with an LSX. The LSX has the potential of up to 2000chp. I don't think I would ever go there because I would have to replace the entire drive train but a 1000chp, 900rwhp, is achievable. Good luck. Hope you have lots of green for repairs if you move forward on your plan.

shade
10-05-11, 05:34 PM
Good info but your research has shown to not what is being seen on the street.
There are lots of 6xxhp and a personal friend rolling 700 to the group with 50+ strip passes and who knows how many WOT blasts.
On an Auto

The Tony Show
10-05-11, 05:37 PM
I work for GM & I own a CTS-V Coupe with an auto, wife also drives it which is wht the auto. I wanted to something similar so I started to ask a lot of questions.

Welcome aboard, and thanks for the insight.

I think how the car is driven plays a big part in how much power it can "handle". I've seen guys blow the rear or trans out of a stock car by abusing it, while others have doubled the horsepower and kept the stock drivetrain intact.

Bushidopupil
10-05-11, 07:43 PM
I'm at 595hp/607tq to the wheels, no probs yet....but ya never know...till she blows...lol

cbloveday
10-05-11, 08:37 PM
I put 30,000 miles and 35 quarter mile runs on my auto tranny.
Tranny was still strong but occasionally had a flare at the track.
I just had it built and will be sure to advise how it holds up and the conditions it has run under.

I drove the OEM tranny within limits on the street and with street tires that give :)
All of my abuse was on the strip with MTs. So I may be a minority in terms of longevity.
I also changed the fluid in the tranny every year FWIW.

Patent Guy
10-07-11, 11:20 PM
I work for GM & I own a CTS-V Coupe with an auto, wife also drives it which is wht the auto. I wanted to something similar so I started to ask a lot of questions. The GM Perfomance Group advises against it. It is not hp but torque that you need to worry about. The 6L90 upper limit is approximately 600 pound-feet. The Performance Group suggested contacting several perfomance shops in the Detroit area which I did, Thompson Automotive and Martin Racing in particular. These are top shelf shops. They actually do development work for GM. Thompson Automotive strongly advised against it modification. Thompson built a Soltice with an 800chp motor connected to a 6L90. They replaced trannies about every 4 weeks. The best GM transmision designers tried custom clutch packs and other enhancements. Nothing worked. I have also talked to some of the GM transmission experts. They all say the same thing, the 6L90 is pretty much near the design limit in a V.

There are a lot of shade tree mechanics out there who will tell you what you want to hear. Just remember they want your money. Unless you can get a rock solid guarantee, I would not advise modifying a V with an auto but its your money. You also need to consider the rest of the drive train as well, not just the transmission. Lastly the LSA is an aluminum block. Increasing boost increases compression. The GM Performance guys stated that could lead to stretching the head bolts and blown head gaskets. Your solution is to sell the auto V and buy a stick V, then replace the LSA block with an LSX block.

My solution is to buy a second CTS-V Coupe with a manual transmission. I have a half a shot at beefing up the balance of the drive train. I also will replace the LSA with an LSX. The LSX has the potential of up to 2000chp. I don't think I would ever go there because I would have to replace the entire drive train but a 1000chp, 900rwhp, is achievable. Good luck. Hope you have lots of green for repairs if you move forward on your plan.

Thank you very much for taking the time to post this information. Up to about 600 lb/ft is about what I would have expected on the unit - at least to reliably survive through the full warranty period. I believe the 6L90 we have is the same transmission used in the Silverado with the largest gasoline engine - so the next transmission up would have been the Allison. Now that would be interesting.

I'm also rather surprised that GM went to the trouble to make the auto, but am glad they did as otherwise I could not own the car. Had to have a family car. I also think the aftermarket will eventually figure out how to strengthen the unit if there are enough people breaking and rebuilding them. Just because the standard parts swaps are not working does not mean some smart individual won't figure out what the new "weakness" is in this unit compared to what "normally" causes failure.

Thank you again luvmyctsv, greatly appreciated.