928sg stage II ITB's and New Cams......
#16
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Also, when you say the engine will be "done" I assume that this means you have some sort of power curve target in your mind. What's your goal, what means being done?
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Hey Sterling you know we love ya, your our insperation.
#17
Man of many SIGs
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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.
#18
Administrator - "Tyson"
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Time to send him a 16V motor to play with.....
Oh come on now, you don't really want that much power, do you?
#19
Nordschleife Master
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.
I'm shooting for 600 RWHP, I don't know if this combination of parts will get me there but it should be close. By ditching the variocam, I will loose some low end torque, but should gain much more in high RPM HP as well as move the peak torque up in the RPM range. My current low end torque results in loss of traction in 1st through 3rd, and I would like to have a smoother torque curve instead of the hammer like torque curve that I currently have.
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.
#21
Nordschleife Master
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.
I'd guess the main effect is removing about 6 pounds of weight from high up in the front of the car.
#22
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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.
I'd guess the main effect is removing about 6 pounds of weight from high up in the front of the car.
I still do not understand all I know about drilling a hole in the center making shafts stronger, just that is does.
#23
Nordschleife Master
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.
#24
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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.
#26
Just saw these in person and they are very nice. And very light. Wow.
#27
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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.
Damned if I know either way, but that is what I have been told many times.
#28
Former Vendor
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.
#29
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That is so true Greg.
That does bring up one point, will Mikes cams lessen the problem with the nose of the cams breaking?
#30
Sterling, we can experiment on my car with that extra stuff.