Superchargers are here!

[Highline Cady]

I agree with Fubar. I've never heard of any weakness associated with the 4T80E. Acklac, you might be right if your running boost, honestly I don't know, but I've never heard that they were "maxed out" from the factory. If that is true that is indeed another reason aftermarket companies won't touch Cady PCM's also.

[acklac7]

Sorry!, let me clarify my posistion on the 4T80e: I beat the piss out of it all the time, never lets me down..It does have a few issues, almost all are related to some sort of electrical sensor (ISS).The gears,bands,clutches etc rarely fail, I've maybe seen a handful of posts regarding these compoenents.

So yes, the 4T80e is a beast, but it is maxed out @ 305ft/lbs...If I get time I will try and dig up the link on Caddy-info. I believe it is from a GM tech website and it notes that the 4T80e is currently at it's limits...I belive Mark was afraid to drive his STS in anything but second untill he got his (Tranny) rebuilt, as I recall the people doing the job said the increase in torque would rip the Tranny out from under the car..lol. BBOB always said a stock N* could take 400hp (or more ?)...The 4T80 is a different story

[AJxtcman]

Come on Bert
You have to have seen this engine in the shop?
It was for a buggy.
The rest of the pictures are from that semi hack/fabricators shop.

[jadcock]

Originally Posted by acklac7

So yes, the 4T80e is a beast, but it is maxed out @ 305ft/lbs...If I get time I will try and dig up the link on Caddy-info. I believe it is from a GM tech website and it notes that the 4T80e is currently at it's limits...

You're right -- GM lists 305 lb*ft of torque as the maximum the 4T80 is designed to handle. Is it coincidence that that's just 5 lb*ft higher than the most torquey engine ever installed in front of it (the VIN Y Northstar)? One would think that they would have used the 4T80 in the LS4 Impalas and Monte Carlos instead of the 4T65, who knows. The 4T80 has a maximum engine torque of 305 lb*ft and the 4T65 has a maximum engine torque of 280 lb*ft. Anyone want to venture a guess as to why the 4T80 wasn't used in the LS4 Impalas and Monte Carlos?

[AJxtcman]

Originally Posted by jadcock

One would think that they would have used the 4T80 in the LS4 Impalas and Monte Carlos instead of the 4T65, who knows. The 4T80 has a maximum engine torque of 305 lb*ft and the 4T65 has a maximum engine torque of 280 lb*ft.

4T65E HD
MN7 Transmission - Automatic 4 Speed, HMD, 4T65-E, Heavy Duty

[jadcock]

Thanks. The HD version doesn't show up on here:

http://media.gm.com/us/powertrain/en...2007/07car.htm

It even lists the MN7 transmission, but doesn't indicate that it's a HD version.

[Raze]

I have to interject a small point, I managed to find one small weakness in the driveline but it's not the tranny, it's the CV axles, if you've ever turned the wheel over and smoked the tires (till the stability system comes on and brakes the wheels) you can actually over torque the joints, I've managed to do it twice, it'll snap the joint and you'll end up with no codes, engine running in gear and can watch the RPMs climb under load but you won't go anywhere You actually have to be real careful cause it's very easy to hit the rev limiter!

Also, back about 2 years ago when I spoke with Mark on the phone after he was inching his 99STS to 500 FWHP and 500+ ft-lbs of torque, he had had no problems, but he rebuilt his tranny with mostly stock parts minus the LSD, I think he also played around with various high stall torque converters but ended up with a mild upgrade compared to stock since he still wanted to keep it daily driveable, while not all-proving, it does go to show the strength of the 4T80e...

[AJxtcman]

2008 Chevrolet Impala
MN7 Transmission - Automatic 4-Speed, HMD, 4T65-E, Heavy Duty
M15 Transmission - Automatic 4-Speed, HMD, 4T65-E, Enhanced Electronic
.
1999 Buick Regal
Regal LS 3.8L, V6 MFI L36 4T65-E MN3

Regal GS 3.8L, V6 MFI/SC L67 4T65E-HD MN7

[eldorado1]

the 4t80e should easily be able to handle 50% over stock.

Just remember torque kills trannies, not horsepower.

[danbuc]

It can also be rebuilt with heavy duty steel/friction plates, which are thinner and stronger, give the clutch packs more grabbing force. There are a few companies out there that will build track ready 4T80E's. They aren't cheap though, so to build one up for a daily driver would be useless. They can be built to handle well over 600+hp, and at least 500+ lb/ft of torque. Such a transmission would really only be at home in something like a Fiero where you could apply F/I to the N*, making it necessary to build the tranny up, otherwise you'd toast the clutch packs anytime you tried to shift passed 70% throttle. That's why Mark would shift at red line, the clutch packs would have just slipped and fried themselves. You'd also probably need some stronger planetary gears sets as well. These could be machined, but would be costly too. With the clutch packs grabbing a hold of 500+lb/ft of torque, the stock gears are likely to simply shear teeth off, or just crack and explode under such force. It happens with TH350's. Their clutch pack design can handle lots of power, but the planetary gear set is the week link. The TH400 trans has additional bracing to aid in dealing with the excessive force transfered from the clutch packs to the gears under high load behind a powerful engine.

I wouldn't trust a stock 4T80E passed 350 lb/ft driving it every day (considering it was driven like I drive my car....HARD!). Anymore than that and I'd consider heavy duty clutch packs to deal with the added force.

As for 40% over stock, that's a maximum torque input of 450lb/ft.....which is a lot, especially for a FWD car who's suspension isn't design to cope with that much torque, let alone what it has from the factory.


The half shafts are a weak point as well. Many 03/04 Cobra owners found themselves snapping half shafts at the track once they upped the power, or in some cases just ran drag radials. The horrendous weight transfer to the rear on our fwd yachts helps ease the stress on the axles, but your still asking for trouble running the kind of power Mark is through the stock units.

As Raze mentioned, the CV joints aren't too fond of excessive torque input either. I bet you could probably have a set of HD half shafts, with beefier CV joints machined for the car as well, but at what cost.

At this point, I've pretty much given up on making the car more powerful, and have decided to focus more on making it more balanced in regards to handling, and managing the power it already has during WOT launches. I feel focusing more on those two aspects then power alone will in the end, make the car much more driver friendly (that is, if your like me and beat the piss out of it almost every day).

[Raze]

danbuc,

if you want to improve handling and overall balance do 3 things:

1) upgrade to stiffer/lower springs (ideally you'd like a matched shock absorber to a given spring rate but slapping on some Eibachs on your OEM or aftermarket passive struts is a heck of a lot better than stock while cornering and much more economical than full on customizable custom made setup...

2) upgrade brakes, get higher quality rotors and pick up some hawk ceramic pads, bleed the brake system, potentially rebuild your calipers, I'd mention other ceramic pads but I don't know of anyone who makes them for Cadillacs. I personally use R1 Concepts rotors, they're not that expensive, crossdrilled and slotted (more for looks) but occasionally I beat on them enough that it makes a difference, and besides for the price of them over high end OEMs I won't feel bad replacing them after 20-30k miles if they crack/warp. I also use Axxis Metal Master brake pads, they're semi-metaillic, semi-ceramic, kinda gives you a fair tradeoff between full ceramics and full metals and provide superior stopping power over even the best OEM 'performance' pads I've tried...

3) TIRES TIRES TIRES, they are not all equal, they do not all handle/perform the same. I never really bought into this with previous daily drivers that I plunked around town in, on my Eldo though I've been through 4 different sets of tires and have tried a number of different kinds due to poor wear (I think I managed to get 22,000 miles out of my last set of Goodyears), I LOVE the new Goodyear Response Edge tires, superior grip, handling, and cornering. They have a VERY flat sidewall compared to tires in the same size class if you're still on your OEM rims that are carbon fiber reinforced for some serious flat cornering. I think they improved lateral grip as much as the springs, together they're amazing.

4/add on) If you have the money a good set of lightweight rims that allow for more air passage they'll help cool your brakes and save you weight which = greater acceleration since your rolling momentum decreases!

5/add add on) Remove all weight from your car I don't mean gut it, but if you really want to up performance realize that every 10 lbs off your car is equivalent to about 1 hp

[danbuc]

I'm in the process of doing all that right now....it's just I have near zero funds so it's been a long...long process. I run Hawk Ceramic pads all around. I've got Toyo Proxes on the car...second set actually. I wanna pic up the strut tower brace, and thicker front/rear sway bars. I'd like to get my hands on a set of lightweight 17" rims....been thinking about getting a set from CardioDoc off ebay or whatever, but again.....money is the key problem.


...And yes they would most likely be Cadillac Rims.....or maybe some other GM brand, no aftermarket crap though.

[AJxtcman]

I am in rough numbers, but $12,000 installed
This is for a complete engine, harness, ECM, TCM, all the fluids, Super charger, T-body, belt, P/S pump setup, IPC if needed, VTD module if needed.

[msta293412]

I am in rough numbers, but $12,000 installed
This is for a complete engine, harness, ECM, TCM, all the fluids, Super charger, T-body, belt, P/S pump setup, IPC if needed, VTD module if needed.
......uh.......What?

[AJxtcman]

I think it will run about $10K, But I padded it by 2K.
That would be low mile replacement engine, Replacement GM engine Control Managment ( ECM ), Harness, Tranmission Control Module (this is needed because you have an ECM not a PCM), Software upgrade, Blower and drive system, 80mm T-body, P/S relocation kit, Set up the ECM to read Class 2.