800T clutching

[turbo800]

What is everyone running for a clutch setup in their 800 turbos?(Ramps, springs, helix, weight, etc)

I've had some issues last season. First half of the RPMs is under revving on boost, then the second half is over revving. I'm running the Thundershift weightable arms, Team 44* straight helix, 287 ramps, can't remember how much weight(I'll weight them later).

 

[swrev]

I was running 441 ramps w/ 43/47 secondary-stay away from that combination. Unsure of springs and weight See pic of bolt in my arm-pretty hefty. No problem building rpm-overrev when running across flats and blew one belt last spring. Lazy backshift is my biggest gripe. Going to work w/ Dynamoe Joe and figure out a better combination. Sled has 163 track and I run 10 plus lbs of boost most of the time.

 

[turbo800]

I think DJ could come up with something great. I'm running the TRA2, but have a spare TRA3 to use. TS arms for both. I'm thinking bout machining my own ramps. Something that will build RPMs in the lower portion and allow for aggressive upshift in the top...

BTW, running a 159" track and 10-12 lbs...

 

[Visi]

What kind of gearing is everyone running? What about Helix cut for a team tied?

 

[highmark00700]

I was running 441 ramps w/ 43/47 secondary-stay away from that combination. Unsure of springs and weight See pic of bolt in my arm-pretty hefty. No problem building rpm-overrev when running across flats and blew one belt last spring. Lazy backshift is my biggest gripe. Going to work w/ Dynamoe Joe and figure out a better combination. Sled has 163 track and I run 10 plus lbs of boost most of the time.

Big bores tend to like the 441 ramps but in my mind seem backwards for a turbo? I could be wrong but they seem to get a lot of upshift in the bottom to mid but have a steeper final on it. I have been thinking of machining a set out of alum to get the prifile right then make steel ones but im nervous the weight difference will mess with things when i build the steel ones. I want something that has a steeper profile initially (kinda like an engagement notch but smoother) and flattens out for mid to top upshift. Im currently running 415's that have been ground a little. I get back shift but initially i load the motor to much. It works great at my house at 4500 ft but at 10k its to much upshift to fast.

Visi : Im running 21- 43 in my rev w/ 159 and riding around 6-10k ft.

 

[swrev]

Running 21 top 49 bottom.

Highmark00700--I agree 441 is wrong for turbo, work fine for a motor producing torque down low. Mine did not have any numbers to identify, so I pulled the ramps out of the big bore to compare w/ and they were the same profile. I had never bothered to indentify the ramps until this past weekend.

 

[Dynamo^Joe]

Slow the upshift down at the beginning with a 415 angle then blend into 441 as the shift increase.

My mountain ramp blend I made back in 09

 

[Octanee]

speaking of DJ, i assume dynamojoe, and this is a 1000 SDI, but ive got his clutch kit in my 1000, then i put a turbo on, the only thing i've changed is that i loaded my arms with all the weights the kit came with, for maximum weight, worked fine for me at 5 psi, throttle was pretty good with my turbo,

ill just link a vid to show you how it seems to be, its a work in progress but i wont complain about my on off throttle, my fueling was not right so slower on the turbo spool, but seemed ok

http://www.youtube.com/watch?v=5l3g382R_2g

 

[highmark00700]

DJ thanks for the link. That confirmed what I was thinking about the 415 ramps i ground. They are very similar to yours. I think I left just a tad more out at the tip than your mountain ramps for hopes of having a little faster backshift when I dump the throttle then get right back in it. They seem to work really well at lower elevation but still a touch to fast of upshift at 10k ft. I will try to post a quick sketch of what im thinking of milling out.

 

[Visi]

I like the look of those mountain ramps.

 

[turbo800]

DJ,
I've drawn up 3 ramps. Tell what you like or don't like about them. Thanks.

 

[Dynamo^Joe]

DJ thanks for the link. .... for hopes of having a little faster backshift when I dump the throttle then get right back in it. .... but still a touch to fast of upshift at 10k ft. I will try to post a quick sketch of what im thinking of milling out.

Then take the finish angle of your helix and lower it by at least 2 degrees.

 

[Dynamo^Joe]

I can't say whether I like a ramp or not, who am I to say anything about me liking ramps.

I can look at the curve of the ramp(fact) and apply Aaen's ramp angle theory(law) then judge by explanation of what I see. Whether I like it or not is not relevant.

From a>b the lever is going to push hard and aggressive like a 414 short track 800 ramp, and lug the engine until a certain track speed to which the engine power can overcome the angle and then engine speed will eventually increase.

From b>c the rpms will continue to raise (due to increased ramp angle) until the lever roller achieves point "C".

From c>d the lever will push hard again somewhat (due to lower angle again) and what the rpms would do I dont know.

From d>e the lever will start to push less hard and whether rpms increase or stay the same, I don't know.

Opinion in brief - Basically I would say im looking at a ramp that is going to theoretically try to work like a 2-speed transmission. There is a portion in the middle of the ramp that is a raised hump. Lower of the raised hump there is one curve. Latter of the raised hump there is a second individual curve. The hump between the two individual curves mentioned separates two distinct shift characters and shift ratios.

From what I understand about turbos and the rpm difficulties at the bottom end of the shift, I have read or talked to gents that mention they are looking to allow the engine to build rpms and overcome bogs or problems with fuel pressure signal from the exhaust pipe and/or other rpm and low power problems in the first start of the shift. (sorry for long sentence)

I would want a ramp that is less aggressive and allows the engine to build rpms smoothly without a high abrupt engagement. So now you can put an angle into the ramp that will allow the sheave to engage the belt at a low rpms, however "stall the upshift" so that the engine builds rpms through the bottom end. One way you can achieve this is with an oversize roller.
In the illustration, I would take the portion of "A to C" and flip that curve completely over 180 degrees (Mirror image)

 

[Dynamo^Joe]

Nick with 08/R&D Custom Turbo Werx Kit (Garrett) @ 6lbs boost @ 9000~10000 feet.

 

[nuttyn01]

DJ's mountain ramps and helix...great backshift and very snappy. crappy vid with a phone but i wanted to show Joe how well it backshifted and how quickly it gets back into it when you chop the throttle.

 

[nuttyn01]

have you tried over size rollers?

Big bores tend to like the 441 ramps but in my mind seem backwards for a turbo? I could be wrong but they seem to get a lot of upshift in the bottom to mid but have a steeper final on it. I have been thinking of machining a set out of alum to get the prifile right then make steel ones but im nervous the weight difference will mess with things when i build the steel ones. I want something that has a steeper profile initially (kinda like an engagement notch but smoother) and flattens out for mid to top upshift. Im currently running 415's that have been ground a little. I get back shift but initially i load the motor to much. It works great at my house at 4500 ft but at 10k its to much upshift to fast.

Visi : Im running 21- 43 in my rev w/ 159 and riding around 6-10k ft.

 

[highmark00700]

Nutty,

I am currently running the 1mm oversize roller.

DJ,

When you say change your helix angle 2 degrees, would that be like from 44 to 42? If that is the case I have a team ts04 that has a 44 and a 42 helix in it. That would be very easy to try on the hill since im running the 44 now.

When you say mirror A-C, thats what i was thinking when i said kinda like an engagement but smoother. I had pictured it in my mind not going out quite that far though. More like blending it at around the b mark or slightly past? What approx rpm would each letter in the ramp be?

Thanks for the info.

 

[turbo800]

DJ,
I'm not that great with CAD, but appreciate your input.

Here's a new one:

 

[Dynamo^Joe]

Like this?

 

[Bendy]

Mountain ramp blend

Do you stock this 415/441 ramp? How much and how long to get?