Jim M.

What Sterling means is "More than before"! Whether he's talking about the engine, the interior, the exhaust, the body, brakes, etc, etc, etc.

Hey Sterling you know we love ya, your our insperation.

Fabio421

Sterling, I remember you were selling off your old vario-cam mock up stuff awhile back. Did you ever sell it? If so, who got it and what do they plan to do with it? Will you be selling this set of vario-cam cam's and tensioners once the new cams are installed? The vario-cam is way too cool to just let it go away.

hacker-pschorr

I've seen some of Mike's work too, the 928 world is very lucky he's a 928 enthusiast.

Time to send him a 16V motor to play with.....

Oh come on now, you don't really want that much power, do you?

ptuomov

If you are using the VW / INA lightweight hydraulic lifters, according to the VW guys those lifters are good for above 8000 rpm. 034 Motrosports: "We've had good results running these to 8300 rpm using our HD valve spring sets."

If you want to go higher than that, there's a Volvo guy who has solid lifters that fit our engines. He goes by the nic "Fidel" on the Volvo boards, I have some solid lifters on loan from him right now. 034 Motorsports also has solid lifters that will likely fit, I got a sample of those as well. With solid lifters, one would have to lap everything carefully though to avod having to adjust the lash after break in. Not doing anything with these, just using them as paper weights right now. ;-)

There has also been some discussion here based on valve springs. Did you give Mike Simard the reciprocating mass data and did he compute the required spring seated load and spring rate? If not, the EAP 3.9 that I just installed can compute those from the cam profile and reciprocating mass data.

The higher rpms are really seductive in the sense that there's so many nice small challenges to overcome to get an engine live happily ever after at high revs.

600 rwhp is a good number. I think I am about there with the higher top end boost. The car drives and handles well with that. I am not sure that it can use much more than that until farily hig gears and speeds.

On low-end torque: I have over 600 ft-lbs of Dynojet torque, too, but for some reason I don't think the wheelspin is a problem. The tires slip a bit in the first three gears, but in a controlled way. Maybe it's my tires, B RE050A PP's are sticky. Maybe it's the soft stock suspension that loads most of the weight on rear wheels. Or maybe it's the fact that, in transition, the turbo is highly dependent on load. In low gears, the engine blasts by the lower rpms and the boost doesn't build up. The 600+ ft-lbs number is from a slow hydraulically-loaded 5th gear pull where the engine has time to build load and pressure at low rpms, on lower gears in real world the torque is probably lot lower.

928mac

removing the rotating mass should reduce vibration. looks good Sterling

ptuomov

The mass removed is on the axle centerline. On the one hand, removing it does relatively little to the rotational dynamics. On the other hand, leaving it in doesn't do any good at the centerline either, so it makes sense to remove it. But the benefit is not as great as gun drilling the crank pin which is far from the centerline.

I'd guess the main effect is removing about 6 pounds of weight from high up in the front of the car.

blown 87

That has to make them stronger also.
I still do not understand all I know about drilling a hole in the center making shafts stronger, just that is does.

ptuomov

Are you saying that a pipe is stronger than a solid shaft if the outside diameter is the same? I don't think this is true for example for stretching the shaft/pipe, but I have been wrong before. Maybe it's true for other kinds of stresses. This is a topic that I know no Young's modulus about.

RKD in OKC

In bending a solid beam is always stronger than the same material/OD sized hollow beam. The increased strength of the sold beam is minimal depending on the ID of the hollow beam. And hardening doesn't matter if it is done correctly on both. The advantage of a hollow beam is that you can make it a bit bigger and achieve the same strength with much less weight than a solid beam. The longer the span the more effect on the bending strength the weight of the beam itself has.

Vilhuer

What happens to variocam parts?

SeanR

Just saw these in person and they are very nice. And very light. Wow.

blown 87

I have been told that for shafts like axles that they are stronger when hollow like our half shafts, I assumed that the same would apply to a cam shaft, things that have torsional stress, which a cam will have.

Damned if I know either way, but that is what I have been told many times.

GregBBRD

Trying to figure out which one is stronger, in this case, is a bit moot, since the stock cams are cast iron and Simard's hollow cams are high grade steel.

blown 87

Common sense just hit us over the head.

That is so true Greg.

That does bring up one point, will Mikes cams lessen the problem with the nose of the cams breaking?

SeanR

Sterling, we can experiment on my car with that extra stuff.