As far as I understand the VB just increases line pressure and makes the shifts more faster, but with with more power being pushed through the system there has to be a point where the clutch packs cannot handle and start to slip, I have heard that certain VB upgrades can handle 500hp but why take the risk and just go ahead and do the internal clutch packs also...I maybe completely wrong here but there seems to be so many stories on what is supposed to do what.

 

if its creating more heat then wouldnt that mean it would slip faster with the vb upgrade? so how would it handle 450+hp?

 

Good question as I bought up the same point, the answer is that Stillens website states less heat is generated with their upgrade and Sharifs website states more heat is generated with this upgrade and mentions the addition of a tranny cooler to be used.......I have no idea why the difference but I guess that Sharifs is a more sophisticated setup.
This has been covered earlier in this post I think by Gurgen but in regards to SGP's I think.

 

It's been stated by more than a few that the SGP and Forged Vbs are the same. I have no idea where SGP sends theirs to be worked on, but if it's in Socal it's probably the same mod except Sharif is a little cheaper.

 

Bill, if you read my post carefully, I believe I explained in more than sufficient detail WHY the L10 upgrade cannot possibly be as good as the SGp/Forged PErf. one. Think about it... if, say, you are pushing 400-450 lb-ft of torque while the gear and the clutches are engaged, they are not as likely to just start slipping...they are already engaged and there is 3000+lbs of force on them. Now, fast forward to...well..redline... (continuing with the given scenario) you are approaching your 6500rpm shiftpoint still at WOT..and a shift signal is given. You are STILL WOT during the actual shift as one clutch is disengaged... the ecu pulls 4-6 degrees of timing, and the 400 lb/ft of torque becomes about 330-350..even so, as the next clutch is in the process engaging (the next gear) you are at WOT pushing 330-350 lb-ft of torque trying to connect two friction surfaces together...as these surfaces touch, they WILL slip jsut a little before they "grab".... this is the very instance that i am talking about. WITH the Stillen/L10 VB, at this very instance, as I have described previously, you are running STOCK line pressure, because the VB does not have any valves to override the TCM's control of the solenoids. THe SGP/FP VB does...which is what those additional valves are for. Hence you get the higher line pressure DURING THE SHIFT as well, not jsut once the shift has ended. ... I don't think i can describe it more clearly.

Continueing with the description above, why do you think the Stillen VB doesn't shirp the tires? Becuase the shift is done at stock line pressure levels...hence instead of the tires shirping during the shift, it is your clutchpacks that are "chirping", or "slipping"... IMAGINE THAT...and imagine how much damage that does in the long term.

I think if that were to happen, you would get absolutely NO help from them, jsut like we didn;t get any help from them after $4000 350z tranny built lasted about 500 miles before blowing out the guts, which by the way had stock clutch packs. They refused to do ANYTHING, siting that one of the solenoids went bad, and it has nothign to do with their work.

 

Identical product...

 

I googled our trans code and got a hit on this. I called him up and he was very nice and spent a few minutes talking to me. The PowerPacks from Alto are a few more months away, maybe October/November. Aparently Nissan has done many changes in design between the different models that all use the same trans and they need to sort this out. What he did talk about wa sthat the piston in the valve body was very small and needs to be upgradead, and somthing about trimming the lip of the seal on the piston to prevent the seal from dragging and absorbing line pressure. Does SGP or Forged address these issues?

Alto is currently developing a PowerPack for the Input and Direct clutches. This transmission has been showing some early failures for a year or so in Australia and New Zealand. The upgraded packs should be on the shelf by August. The Alto # 174756/A will change the Input pack from 6/7 to 7/8 friction plates; it will also contain a new pressure plate and snap ring. The Alto # 174757 will change the Direct pack from 5 to 7 friction plates.

Best regards,

Roy Baker

Alto Products Corp.
Technical Director
Alto Way • Atmore • AL • 36504
251-368-7777 X- 712 • Fax: 251-446-6712
roy.baker@altoUSA.com
www.altoUSA.com

 

Wow...good info...I will place a call to these guys soon.

They did address this issue, by building the valves to override the opposition pressure, hence effectively speeding the piston's movement from the closed to the open position (this is to the best of my recollection).

 

Two items totally confuse me.Chirping tires is better action/performance from the VB.
I would be surprised if any racer or transmission shop would concur.I have friends with 7,8,9,10 second cars that do not break traction after launch,even DOT class cars,Firm,quick yes.Unfortunately,automatics have some slippage,they also break fewer parts that way because the power is more seamless
Pressure v friction is the same issue as brakes..at some point 4,6 pistons is beyond maximum and you need more surface area to grip
Sorry,temperature.If the shifts are faster and there is less slip why aren't they running cooler?

 

That's because I posted that info on FA back in June and RE5R05A isn't a common term on google. Roy is a very helpful guy. I'm just waiting for their PowerPacks to come out so I can rebuild and prep for FI.

I'm figuring that for the power levels I'm aiming for, if I do a complete rebuild using Alto's standard rebuild kit, the Input and Direct clutch PowerPacks, their CaseSaver, a ProTorque TC and the Forged Internals VB, that should be more than sufficient. Part of me is torn to go to Level 10 since they're relatively close, but they've had such an inconsistent rep, so I might opt to find a more local shop that is capable since most of what I listed above is not out of the ordinary in terms of labor for a transmission rebuild.

I would feel better if hardened parts were available, like they make for other transmissions, but I guess nobody really knows yet if that's a requirement and what those stock parts can hold up to. Things like the input clutch drum, mid sun gear and output shaft I would like to see stronger, but I haven't heard of anybody breaking those yet anyway?

 

The cats out of the bag.