ATTN! anyone concerned about fuel consumption. auxiliary overdrive

[faSSt]

Every SS owner should check out http://www.gearvendors.com/ period. It's an indestructible overdrive unit that sits behind your trany that in effect gives you eight forword gears. We all know that when running down the highway we are spinning at about 2500 rpm which doesnt help the longevity of the engine and kills gas milage. This thing brings rpms way down at highway speed and I was told it would bring milage up to around 25-28 MPG! The application for the SS costs about $2600.

Think about it like this... It improves performance by keeping the engine in a more narrow spectrum of the power band AND IT PAYS FOR ITS SELF IN SAVED GAS.

Im gonna do one of these, the Lingenfelter blower, full exhaust, and do a full air bag suspension AND THATS IT I SWEAR! I also cut out the resonator and took off the rear bowtie and "Trailblazer" emblem.

[steined]

I'll have to admit that I was pretty skeptical, but it sounds plausible (so I am only a little skeptical now!). The price is a little steep IMHO. I would be curious as to how it would work with the 4L70E TCM vs the old 4L60 PCM control.

I think it is possible a 6L80E swap could cost less once we start getting some more GMT800s on the road.

Eric

[Bulldog]

I sounds great but $2600? For a couple MPG it would take a while to recover from that amount.

[TrailblazerSS]

For anyone considering this. The application will cost $3300 minimum. You must buy a new driveshaft. (Not included in the $2600 minimum.)

Anyone wanting to go fast, there is parasitic loss and weight associated with the unit. You will lose some power. If you want to beat that SRT-8, Mustang, Camaro, etc, you will be making it harder on yourself.

The economics: Say the unit helps your average MPG improve from 16 MPG to 18 MPG. (It may help more than that on highway rides, but on the streets it will probably help less.) Say gas costs $3 a gallon. It only takes 158,400 miles to break even. If your going to put that many miles on your ride or drive only highway miles, then it would make sense.

[blautens]

For anyone considering this. The application will cost $3300 minimum. You must buy a new driveshaft. (Not included in the $2600 minimum.)

Anyone wanting to go fast, there is parasitic loss and weight associated with the unit. You will lose some power. If you want to beat that SRT-8, Mustang, Camaro, etc, you will be making it harder on yourself.

The economics: Say the unit helps your average MPG improve from 16 MPG to 18 MPG. (It may help more than that on highway rides, but on the streets it will probably help less.) Say gas costs $3 a gallon. It only takes 158,400 miles to break even. If your going to put that many miles on your ride or drive only highway miles, then it would make sense.

:iagree:
Well said.

[faSSt]

As far as parasitic loss, you only loose 1 horsepower at the wheels for every 400 with these units.

And the $2600 includudes everything needed for the instal, including driveshaft.

I had one of these on my 1996 Impala SS and it worked great! It made the car a good bit quicker and saved gas, nuf said.

[SSportWagon]

I brought this up 3 months ago

http://forums.trailvoy.com/showthread.php?t=3289

You're not going to see/use all 8 gear possibilities though as a few will overlap too much to be effective in SRT-Kill mode.

[TBSS]

I'm very familiar with this company and their products, I've talked with them in person (they are about 15 minutes away from me). I agree that the GVOD unit itself is amazing - bulletproof, really - and their people are stand-up folks. Can't say enough good stuff about them and their products.

But there are a few problems when considering it for our trucks. One, like TrailblazerSS has said, it really makes zero economic sense. So it takes you 100,000 miles instead of 150,000 miles to make back your investment, that's still longer than many people plan to keep their trucks. Not very smart from a bottom line perspective.

While we're talking economics, keep in mind that you don't realize the full benefit of this unit unless you spend close to 100% of your time on the freeway, with the cruise control on. As soon as you get on the gas, or start driving in the city in stop-and-go traffic, you nullify any benefit the GVOD unit would give you. That's why they tout their products for RV drivers, etc.

If you've read their site, you know their unit comes in handy with old 3-speed or 2-speed autos that don't have overdrives to start with...that's when it really shines. We don't have that problem. It would give you, in effect, a .55 overdrive compared to our present .70, and lower the RPM at 75 mph from 2500 to about 2000, but that is still marginally in the LS2's efficiency range. A much better cruising RPM would be 1800 rpm, where you would likely see an additional 2 mpg.

A cheaper (and much more fun) solution to the gas mileage issue would be to replace your 4.10 gears with 3.42 gears, and get a 3000 rpm stall converter. That way, you get killer torque off the line (due to jumping right into the power band), yet you still get your 2000 rpm cruising rpm at 75 mph when the converter locks up. This would cost you less than half of what a GVOD with installation would cost.

While we're on the subject of price, the GVOD for our units would be $2595 + $650 for install, or around $3250 if you have them install it. If you have someone else install it, I would expect somewhere between $1000-$1500 for an install, putting you well over $3500 for the entire package if you are not in the area. Conversely, you could do gears and a converter for about $1500.

[Bill00Form]

For anyone thinking about this, I think you should consider GM's new 6 speed automatic. It will increase the strength of the trans (I thought I read there will be 5 versions), which some are saying is a week link, as well as provide the other benefits from the gear ratios. I don't know pricing but can't be too different.

[tblazed]

For anyone thinking about this, I think you should consider GM's new 6 speed automatic.

What about interfacing a 6-speed with the Powertrain Control module? Since the stock trans is electronically controlled, you'd need to have a way ( pcm programming software or ??) to set up the computer to work with the 6-speed IF all the control solenoid and sensor connections are there.

[SSportWagon]

I can almost guarantee you that a Brandy-New 6 speed tranny WITH a Torque Converter is going to cost you over 4K ... if it'll hook up to the TCM. Then there is the question of whether it'll even hold up to > 400hp/tq in stock form. I looked into putting a 4L80 into my hotrod to replace the TH400 ... and to build it to withstand ~550hp/tq, plus converter was going to cost ~5K :duh: . Since I already have a well-built TH400, the GVOD is the "easier" solution.

I agree, 3.73 + converter is the way to go, but isn't a 3K too loose for extended loafing at 2000 rpm ?? will all that slippage generate too much heat ?? Is it a lock-up Converter ?? I wish they offered 3.73's ....swapping them into a 2wd is fairly straight foward - anyone know what it would take for the AWD version ???

The only time you really want the 4.10's is for getting out of the hole and a +4500# brick needs all the help it can get doing it. My guess is GM dropped the 3.73 option when they had the final #'s in on the performance of the SS and saw how far off the 3.73's put it from the SRT #'s.

....With my TH400 setup I kind of cheated my way around this - I've got a steeper 1st and 2nd gearset installed than the stock one. This takes my 3.42 rear ratio and effectively makes it look like ~3.73's in first and ~3.6 in 2nd. TOo bad there aren't other gearsets available for the 4L70E ....or are there ??!?!?!

[PediDr2]

How about a good 'ole T56 swap :thumbsup:

[TBSS]

The beauty of the 6L80/85E is that with a 4.02 1st gear, you won't need converters to give you your torque. No slipping, no tooling around the Target parking lot at 2500 RPM, a definite downside of a loose converter.

With a 4.02 1st gear you could put 3.73's in the rear, and get a final drive ratio of 15.0. That's much more off-the-line power than we have right now with a final drive of 12.5.

If and when the 6L80/85E comes out, it will happily handle 400 FWHP in its most stout iteration. This is a great development for GM (if not 3-5 years late :hissy: ).

[Red SS]

How about a good 'ole T56 swap :thumbsup:

:thumbsup::thumbsup::thumbsup:

[steined]

One good thing about the 6L80 is that it is being placed in some of GM's highest volume vehicles. That means there should be a ton of them floating around sooner rather than later. If the new Silverado's get them, we'll be in good shape (assuming it isn't a 6L60 variant that they get). I can't see GM making a bunch of different iterations of its new transmissions, they probably learned a thing or two about having so many different versions for so many different applications.

I also suspect that it will be driven by a separate controller just like the TBSS. If so, it shouldn't be hard to figure out how to interface it. SOMEONE will figure it out. Trust me! :D Probably just in time for the 3/36 to expire!