Majinvegito123

Hey guys. I'm building a high powered GTO that will almost exclusively be on the street except for a few passes here and there on the track. We've got the rear end and motor being built, and we're anticipating upwards of 1000whp. Not ideal for a street car by any means, but nonetheless. We're stuck on transmissions though because the car is mostly a highway cruiser that I bring to work, but otherwise it's driven from stoplight to stoplight when i'm grabbing an ice cream or something to that effect lol. Anyway, we're trapped on a TH400 or a 4L80E. I've read a lot of threads about the differences between the two, but they're not all quite what I'm looking for and I haven't found something for my particular application.

Again, 800-1000whp street car mostly. Would the 80e be best? I know these things are expensive to build in comparison to the th400, but would I even notice a significant difference on highway speeds? I know the TH400 is also lighter, but I've read things about calibrating the speedo etc. What do you guys think?

AnnivSS

Following because I have a similar situation.

Jays_SSZ28

iTrader: (2)

What do you think your cruising speed will be?

You can calculate RPM with an easy math equation.

No overdrive is approx 1000rpm higher. It might get annoying after awhile.

Getting the speedo to work is not a big deal. This is all assuming it's a mid 2000's GTO and not a classic.

Majinvegito123

i will be cruising on the highway at around 70 MPH. There are areas where it will be 60 MPH But it will never be less than 60. And yes this is a 2005 GTO.

vorteciroc

Since you guys are comparing an automatic transmission with Over-Drive (4L80E) to an automatic transmission without Over-Drive (3L80/ THM400)...

What will the rear tire height (Diameter) be?

What will the differential ring and pinion ratio be?

Then you guys can figure out some engine RPM numbers for a given cruising speed...

Also... What is the current vehicle weight, without driver?

TTur1996

After destroying 2 professionally built 4L80 trans with a brake, all the goodies, and the HP your talking about. We got a TH400 with a brake and haven't had a problem since. We run 28's. To be able to run 28's on the highway you would at least need to drop to a 3.40 gear and that would still be spinning it to right at 2800rpm at 70 mph. Why would you even want to drive a 1000HP car to work on a daily basis? How long do you think it would last doing that? You might want to think about getting yourself a daily driver for work. 8hrs at work is a long time for weather to change. Any type of tire you put on there that will even remotely hook a 1000hp car is going to be on ice in the rain.

MaroonMonsterLS1

80e for street driven. No questions.
Overdrive
Lockup
Electronic Shift Control (this is better for racing and for daily driving)
The gearing is the same 1-2-3...uses same planet sets, same direct/intermediate clutches.

without a doubt the 80e is the way to go for anything thats ACTUALLY going to get street miles put on it every year.

TTur 1996 what were your issues with the 80e? Not sure why you would blow up two of them

Majinvegito123

Well, I’m building this car to last... as long as it’ll last. Iron block with some nice forged internals however we are trying to limit the power whichever way we can. I was interested in the 80e simply because of its street driving goodies such as lockup and electronic shift control, but I wasn’t sure how to compare the two in terms of reliability, cost, and street mannerisms

MaroonMonsterLS1

Properly built, an 80e is equally reliable to a th400.
They usually cost more and have more expensive converters
Street mannerisms are the same (or I would argue better) with the 80e. Electronic pressure control allows you to have not-too-firm shifts when just cruising around, but then you still get full line pressure when you need it at WOT. Transbrake th400's are fixed line pressure and can be a little more agressive to drive on the street. Plus having to move the stick isn't as easy as having the computer shift like grandma's buick when cruising.

Majinvegito123

id have to agree with this. I’ve heard varying information on installation into GTOs - are they fairly easy to install? (80e I mean). And as for racing application, is the 80e going to perform as well if not better? I know that they have the same gear ratios. I’d rather not feel like I’m slamming into every gear shift

vorteciroc

For the OPs Lower Power level in the 1,000 HP range. The 4L80E would be the ideal route to take for soo many reasons!

The only reason; I personally would go back in time technologically, with the 3L80/ THM400 in the OPs desired situation...

Would be if the power were higher, up in the 2,000 HP ...And then a Gear Vendors unit would be needed to retain Over-Drive.

Majinvegito123

are your reasons the same as above posters? Also, are the gear vendor overdrive units worthwhile as an addition to the 80E

TTur1996

With an 80 they do not make a SFI case for it to my knowledge. At 1000whp you will need to use a blanket to keep yourself safe. Then you will have problems keeping the trans cool while street driving. Then you have the problem with tuning the pressures in the 80 for it to handle the power. And every time you change anything HP wise or gearing you will need to get the 80 retuned because its electronic. Total PITA. I'm just trying to let you know what your in for. Do what you want. Good luck Just so you know if they were so great why doesn't anyone with the type of power level your talking about use one. But I guess If your not going to actually use all that power then you will be fine. Because to utilize that power your going to have you will have to do quite a bit to your chassis to get it to the ground anyway.

Majinvegito123

as far as I know, Jake’s performance offers excellent 80e transmissions. However, I don’t really want to go through the struggles you’re mentioning regularly. I wanted a one and done solution regardless of the costs. However, most of these issues seem to be the same ones I had been running into with my 65e. Example: we had an issue with line pressure and had to have it retuned on horsepower changes. I throw the car on the dyno for necessary changes, but I hadn’t factored in temps

MaroonMonsterLS1

The list of things wrong in this post is longer than the list of things right.

There IS an SFI case. Made by Reid (expensive as hell and very limited production...but it exists)
Regardless...I know of 1500+ through a stock case 80e
There is also the option of an SFI bellhousing also from reid that can be used on a stock case

You will NOT have trouble keeping the trans cool while street driving...it will be easier than keeping a 400 cool. 80e has lockup. That's where all the heat comes from in a trans...the torque converter slippage. Lockup drastically knocks that down.

You do not have issues tuning the pressures. You can leave a stock pressure table in there, and it will usually be spot on if the proper internal mods have been made. 180 psi line will take 1000 horse. Put a gauge on it if you arent sure...but it'll be fine if the trans is ok mechanically

You don't need to retune the 80e all the time...it's not that big of a deal. If you change tire size or gearing on any electronic transmission...even in a stock pickup or grandma's cadillac...you should retune it.
Most racers aren't switching diff gears every weekend.
If you're worried about it...you can manually shift the trans

Yes, the 80e is a little more work. It will require some wiring, some minor computer tuning...but as a whole, the benefits outweigh the costs in my opinion.

vorteciroc

Yes, the same reasons, so far I am in complete agreement with MaroonMonsterLS1 on this one.

No, I do not feel it is worth while in addition to the 4L80E.

For those who seem uneasy over the 4L80E being electronically controlled and requiring tuning...

I first explain, that this is the latest and greatest way to experience one of these transmissions...

However, should a person feel hung up on this notion... I do offer non-electronic options as well.
Mostly... As long as a person is happy with manually shifting the transmission; then no tuning or module is needed. The valve-body will be operated electrically instead of electronically.

MaroonMonsterLS1

Anybody with wire snips and crimpers can make an 80e electronically controlled.

There is a short list of internal mods you can do to make it safer/last longer if you do it...but I know guys get away with just doing the minimal wiring mods.

Easy as pie

madmann26

Before about 2 weeks ago, I hadn’t touched my 80e tune in well over a year and I beat the **** out of it.

The only reason I updated the tune 2 weeks ago is because while the trans was out for a rear main seal, I had the converter swapped with a new 258mm triple disc and then the only thing I adjusted was shift points.

Didn't touch pressures.

Majinvegito123

My car is a 2005 GTO. I'm not sure why electronically shifting would upset anyone in this day and age. In my eyes, if someone wants to manually shift a transmission they'd be better off just doing a manual. At least you'd get some interaction in that regard. Do you guys recommend Jakes Transmissions as a provider? I was quoted about 5400 dollars for a nice 80e that would be able to handle my 7500+ RPM revs with a triple disc

MaroonMonsterLS1

Yes. Jakes is a sponsor here. He makes great products and really knows his stuff. Great company.