[Tom McQueen]

My custom turbo cam card was not very complete. I understand that the turbo guys want to keep some things to themselves, but we cant properly install it without at least a little pertinent data. So we sent it to Cam Motion and had them put it on their Cam Doctor and spec it out completely. Took about a week and we now have all the necessary information. And then some. Painless and fast, so a process I can recommend.

And no, I will not be posting the specs.

[v869tr6]

Who speced the and what are the specs, LOL

[BruceWilkie]

Cost??? I have done a few manually which isn't a fast or easy process that requires lots of repeat work to be certain. Educational but if cam doctor service can save me all that time it might save me money in the long run.

[Jack Gifford]

Ditto to Bruce's post. Cost?

[Tom McQueen]

Until we get the cam back (its in transit) I won't know the price. Will post it when I have it.

[Tom McQueen]

So my turbo cam came back all measured up. My 'guy' does a lot of biz with Cam Motion and the price was only $20.00 for the computer measure. I do not know if that is the regular everyday price or the good guy price. But even at twice that much its a bargain.

They measure one intake and one exhaust. For each lobe you get;

Lobe centerline
0.050" lift centerline
runout
peak open acc.
peak nose acc.
peak close acc.
lift at TDC
duration from .006" to peak cam lift in .050" increments.
open and close degrees at .006" to peak cam lift in .050" increments.
Area from .006" to peak cam lift in .050" increments.
peak valve lift

overlap can be calculated at virtually any measured lift/duration.
--------------------------------------------------------------------------------
You supply the camshaft, roller lifter specs (wheel OD) and rocker ratio.

[Tom McQueen]

Originally Posted by v869tr6

Who speced the and what are the specs, LOL

------------------------------------------------------------------------------------

I can answer half this question. I bought the pair of turbo's from Steve Morris. He has Bullseye Turbo build his turbo's using the Borg Warner S400 frame. I upgraded my compressor (75mm) to a billet version with the B/W race compressor housing and upgraded the turbine housing to a S/S V-band mount.
SME and Bullet worked out the cam specs. If you go to SME's website one of the video's is of a Pontiac 455 twin turbo using a pair of 66mm. That engine made over 700 ft lbs at something like 2200 rpm. I told Steve that's the kind of low end power I was looking for in my build.

[Jack Gifford]

Thanks Tom. I assume your "acc" denotes acceleration? Are the units inches per degree-squared of cam angle? What was the peak negative acceleration of your lobes? Did they provide plots of velocity and acceleration? Did they give any values of jerk (rate-of-change of acceleration)?

[Stan Weiss]

Originally Posted by Jack Gifford

Thanks Tom. I assume your "acc" denotes acceleration? Are the units inches per degree-squared of cam angle? What was the peak negative acceleration of your lobes? Did they provide plots of velocity and acceleration? Did they give any values of jerk (rate-of-change of acceleration)?

Jack,
If you (or anyone else) can provide me with lift data every x degrees of rotation (where x can be any number but the smaller the better) I can graph lift, velocity, acceleration and jerk for you. I produced these graphs from a Comp Cams SBF Roller cam file that someone sent to me. The every 2 degrees is because the cam was measured at every degree and I wanted to see it against other plots which were done in crank degrees. Also these are raw plots with no smoothing applied.

Stan

Sample Input data

; I = 84.25 E = 300.5 - 35-999-3 Ford Windsor Roller
; 1.65:1 Rockers - Lash 0.021 - 0.021
every x degrees = 2 S96 data
Intake
.00051181
.00053325
.00059787
.00070866
.00086771
.00107008
.00131437
.00160577
.00196850
.00243930
.00304889
.00381890
.00475451
.00584871
.00710212
.00854331
.01020559
.01211464
.01429134
.01673228
.01942826
.02237942
.02559157
.02909931
.03293919
.03712214
.04164444
.04649151
.05165082
.05713510
.06296322
.06913754
.07565334
.08248426
.08960630

_______I__N__T__A__K__E
Rocker_Arm_Ratio_=_1.650_________Valve_Lash_=_0.02 10_________Valve_Angle_=_20.0
VALVE_____Lift______Opens___Closes__Duration
_________________Deg_BTDC__Deg_ABDC_____________Ar ea
_________0.00000____47.69_|__84.37_|_312.05_|__61. 01
_________0.00600____44.55_|__80.80_|_305.35_|__60. 99
_________0.01000____42.73_|__78.67_|_301.39_|__60. 98
_________0.02000____38.71_|__73.99_|_292.70_|__60. 91
_________0.04000____32.32_|__66.84_|_279.16_|__60. 69
_________0.05000____29.68_|__63.94_|_273.61_|__60. 56
_________0.10000____18.96_|__52.59_|_251.56_|__59. 70
_________0.15000____10.52_|__43.84_|_234.35_|__58. 68
_________0.20000_____3.06_|__36.19_|_219.26_|__57. 27
_________0.25000____-3.97_|__29.07_|_205.10_|__55.41
_________0.30000___-10.85_|__22.20_|_191.36_|__53.71
_________0.35000___-17.79_|__15.20_|_177.41_|__51.04
_________0.40000___-24.96_|___7.98_|_163.03_|__48.74
_________0.45000___-32.52_|___0.38_|_147.86_|__45.30
_________0.50000___-40.80_|__-7.88_|_131.31_|__41.46
_________0.55000___-50.19_|_-17.26_|_112.55_|__36.16
_________0.60000___-61.45_|_-28.50_|__90.05_|__29.76
_________0.65000___-76.72_|_-43.55_|__59.73_|__20.32
CAM
_________0.00600____56.01_|__92.95_|_328.96_|__39. 04
_________0.01000____50.50_|__87.43_|_317.93_|__39. 00
_________0.02000____41.86_|__77.65_|_299.51_|__38. 83
_________0.04000____30.98_|__65.35_|_276.33_|__38. 48
_________0.05000____26.89_|__60.95_|_267.84_|__38. 29
_________0.10000____11.47_|__44.82_|_236.29_|__37. 07
_________0.15000____-0.70_|__32.36_|_211.67_|__35.53
_________0.20000___-12.08_|__20.95_|_188.87_|__33.37
_________0.25000___-23.72_|___9.23_|_165.51_|__30.83
_________0.30000___-36.39_|__-3.48_|_140.13_|__27.21
_________0.35000___-51.53_|_-18.59_|_109.88_|__22.27
_________0.40000___-72.76_|_-39.65_|__67.59_|__14.31

_________Minor_Intensity_50.09
_________Major_Intensity_31.67

[Jack Gifford]

Originally Posted by Stan Weiss

... I can graph lift, velocity, acceleration and jerk...

I've done that myself for all my performance cams. I was just curious what the "Cam Doctor" output includes.

Detail: the units on your sample acceleration graph are not in the range of values that inches per degree-squared at the cam would be. What are the units?

[Stan Weiss]

Originally Posted by Jack Gifford

I've done that myself for all my performance cams. I was just curious what the "Cam Doctor" output includes.

Detail: the units on your sample acceleration graph are not in the range of values that inches per degree-squared at the cam would be. What are the units?

Jack,
All of those are in crankshaft degrees. In camshaft degrees it would be this.

Stan

[Jack Gifford]

Thanks. Those numbers make sense.
Unusual to see a "disturbance" in the middle of the negative acceleration range (@ ~100 cam degrees).

[Stan Weiss]

Originally Posted by Jack Gifford

Thanks. Those numbers make sense.
Unusual to see a "disturbance" in the middle of the negative acceleration range (@ ~100 cam degrees).

Jack,
I did not roll that cam, those are just some numbers that someone gave me to use.

Do you graph any of the derivatives past jerk (I remember hearing them called snap, crackle, and pop like the rice crisps serial )?

Stan

[LPI]

Hi Jack,

Here is an example of the output from the Cam Pro unit.

[Jack Gifford]

Originally Posted by Stan Weiss

... Do you graph any of the derivatives past jerk ...

No. In fact I don't generally get concerned with jerk, except when it indicates a discontinuity in the lobe profile (poor smoothing of CNC digital data, etc.).