Hi all,

No, this isn't a snake oil sales pitch. I'm trying to see how many people would be willing to pay for a trans modification to their nv4500 to make it shift much faster. Here's the scenario:

There is a company, called liberty's gears, that specializes in performance manual trans modifications. In fact, they make their own clutchless manual, but I digress...they have two modifications they can do to make manual transmissions shift faster and easier. One of those mods is called proshifting, and the other is called faceplating. Apparently, both processes achieve the same goal in different ways. Faceplating is the more durable process according to them. I do know for a fact that their manual trans work is well respected, and is used by many racers. I know that I've heard of getting a trans proshifted for years now.

They have to develop the process for each type of transmission, one size does not fit all. They have not developed either process for any of the nv transmissions used in our trucks. My idea is this: Many of us like to run our truck stoplight to stoplight, and/or on the dragstrip. As we all know, the autos beat the daylights out of us at comparable power levels because they don't have to lose boost between gears. Many of us are otherwise satisfied with the performance of our 5 speeds, but would just like to at least narrow the gap between the auto and the manual in a race.

Assuming they will develop the faceplating process for the nv4500, I don't know how much they would charge to modify a transmission, but I think $700 would probably be a good estimate. Here's a link to a page on their site that has the pricing for faceplating and proshifting:

http://www.libertysgears.com/services.htm

In my estimate, I assumed that most people would get 4 gears done, and not knowing how many sliders would be involved in that, I assumed 4 sliders as well, at $50 per slider. Finally, the $195 labor was added, for a total of $695, rounded to $700.

How many of you would be interested in this at roughly this price? I'm hoping it could give 80% of the drag race performance of an auto for about 15% of the cost.

Please let me know your opinions here-I will be forwarding this to Paul at Liberty's Gears if there appears to be much interest.

 

Sounds like a good thing

But i kinda dont see a manual very well for racing, although this is a good thing, I got my manual for towing, but if it dont mess up performance with a load behind me, i would sure be interested, in the least expensive upgrade.

Question is tho, how would this process be on the clutch, flywheel, and the synchros? What kind of warranty would this have? and finally what is the difference between this and a clutchless or synchronized tranny?

Wouldnt a synchronized tranny be just as quick? A clutchless manual or a hydrostat (wishful thinkin on that one tho)

I like the idea, it just poses more questions than answers... but theres still hope

Rick

 

This is the only thing that concerned me when reading, and since my truck is work first... "Pro shifting and face plating serve the same basic purpose" and "Neither are synchronized, so they make street driving difficult" I agree with Txdiesel if it would not affect my daily driving/towing I'd be interested but don't want a $450 a month friday/saturday night toy.

 

That's true, and that's why we need more info on exactly HOW difficult it is. That is often determined by perspective. I'll give you an example: I got a southbend dual disk clutch and put it in my dually. Against Peter's advice, I did not install the hydraulic upgrade to lighten pedal pressure. To me, it's not a problem. I don't mind the extra pressure. Apparently, some people are really bothered by it. See what I mean?

No doubt, whatever extra difficulty it may entail will be too much for some people, and the more difficulty it adds, the more people will feel that way. But, I know that proshifted transmissions are quite often driven on the street-I've done it myself. I don't remember exactly how it was, as it was several years ago. But, I don't recall feeling like it was very difficult at all.

 

I am interested in the idea, as I have often thought about trading mine for a auto (but i like rowing gears so its a double edged sword), partly due to the wife partly because in town I get spanked my mopeds even though I am near 500 rwhp. I have a heck of a time getting it rolling and have alot of lag in the 3rd to 4th shift. Keep updates coming. I wish they would event somthing that would hold boost pressures up to enable the next shift to start at say 20 psi and ramp up instead of 0 psi and blowing black smoke

Jason

 

I would be very interested in this. Evan if it involved a little learning curve. But not at the cost of durability.

 

I would be interested, however they would have to make one for the nv5600. 6speed.

 

That's a good thought, and it's what blowoff valves are often used for. Blowoff valves vent the pressure spike that occurs when the throttle valve snaps shut. The air coming from the turbo is suddenly blocked by the now-shut throttle, and the blowoff valve lets it vent to atmosphere, avoiding turbo damage from sudden deceleration. This also keeps the turbo spinning faster than it would have if the pressure spike were allowed to build and stop or greatly slow the turbo. The problem is, our diesels don't HAVE throttle valves, so there's no big pressure spike. I have watched my boost gauge, and it does not register any spike upon sudden deceleration from high boost. This tells me that the deceleration it does experience comes from the fact that between gears, the engine is not producing much exhaust. Put differently, I think the exhaust turbine side is slowing it down rather than the compressor side. This gives a blowoff valve nothing to work with, since it's in the intake tract.

 

Its still the same thing though. When you jump out of the throttle, you lose your drive pressure, which was driving the turbine. Since the intake tract is still pressurized, it will flow to a lower pressure area, like atmosphere. Out the compressor is the easiest way. Since it is flowing backwards now, it is going to slow down/stall/reverse the compressor. If you had a BOV to vent off the intake charge, then that would be the path of less restiction, and should keep the compressor from slowing down/stalling as much.

 

Yeah, you're right that the intake tract is still under pressure. If you could trigger that blowoff valve with a throttle position sensor, that would work. You would need that because there's no actual pressure spike to trigger it like on an engine with a throttle plate.

 

Maybe it could be triggered on a pressure switch from the exhaust side. Lose the drive pressure, blow off the intake.

 

you DO NOT want a pro-shifted tranny in a daily driver... you've got to match-rev to downshift, and it ain't always gonna downshift... it's designed for dedicated drag applications