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Search found 2842 matches

by Stan Weiss
Tue May 19, 2020 8:49 am
Forum: Engine Tech
Topic: Camshaft math and explanation for idiots.
Replies: 8
Views: 891

Re: Camshaft math and explanation for idiots.

ECL = LSA + (LSA - ICL)

IVC = (Intake duration / 2) - ICL

EVC = (Exhaust duration / 2) - ECL

IVC = Duration - ( IVC + 180))

EVO = Duration - (EVC + 180)

Stan
by Stan Weiss
Wed May 06, 2020 12:05 am
Forum: Engine Tech
Topic: Which Cam is Faster?
Replies: 8
Views: 645

Re: Which Cam is Faster?

If these are actual / real lobes then what are their 0.200" duration?

We can calculate average average velocity from 0.006" to 0.050" but that does not mean that the one with the higher average has the higher peak.

Stan
by Stan Weiss
Fri May 01, 2020 12:32 pm
Forum: Engine Tech
Topic: Has racing been completely shut down?
Replies: 102
Views: 4340

Re: Has racing been completely shut down?

No question we need way more testing. But there is also the question of just how accurate these tests are?

Stan
by Stan Weiss
Fri May 01, 2020 11:57 am
Forum: Engine Tech
Topic: Has racing been completely shut down?
Replies: 102
Views: 4340

Re: Has racing been completely shut down?

Work of Los Alamos scientists suggests COVID-19 can turn really bad again much faster than it got better Los Alamos scientists estimated how fast the curve is flattened in 51 countries. They determined that arbitrarily re-opening societies can allow COVID-19 to undo that progress much faster than it...
by Stan Weiss
Fri May 01, 2020 10:24 am
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

How does greater valve seat angles which reduces effective curtain area at lower lifts come into play? I believe that this has been talked about before but can not find it. Stan Bill, If you measure the flow / pressure in the port and now have that same flow throw a 50 or 55 degree seat @ .100" val...
by Stan Weiss
Thu Apr 30, 2020 10:38 am
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

hoffman900 wrote:
Wed Apr 29, 2020 10:25 am
My graph from an old thread. Simulated mass flow vs piston position vs valve lift profile.
Bob,
Does EngMod4T show / let you graph cylinder pressure? If so what is your cylinder pressure @ IVC.

Stan
by Stan Weiss
Wed Apr 29, 2020 3:38 pm
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

If my intake valve closes @ lets say 80 ABDC. Then the piston has been compressing the air / fuel mixture for 80 degrees. How much above outside BP is the pressure on the back side of the valve to continue to have flow into the cylinder?

Stan
by Stan Weiss
Wed Apr 29, 2020 12:07 pm
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

How does greater valve seat angles which reduces effective curtain area at lower lifts come into play?

I believe that this has been talked about before but can not find it.

Stan
by Stan Weiss
Tue Apr 28, 2020 1:55 pm
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

What I like to do is look at the intake port flow graphed as a function on the valve lift curve.

Stan
by Stan Weiss
Mon Apr 27, 2020 4:03 pm
Forum: Engine Tech
Topic: Intake valve lift at BDC
Replies: 51
Views: 1963

Re: Intake valve lift at BDC

Mike,
I know these are not your lobes. But looking at these lifter raise ATDC and rocker arm ratios I don't see how they could only be .290" ABDC. Are these that different than yours?

Stan
Comp_TS_Lobes.gif
by Stan Weiss
Wed Apr 22, 2020 9:02 pm
Forum: Engine Tech
Topic: Port length BBC heads
Replies: 6
Views: 486

Re: Port length BBC heads

Little Mouse wrote:
Wed Apr 22, 2020 6:41 pm
Thank you lots of useful detail. So it's hard to compare the two on volume as like in velocity.
I do not understand. You should want around the same velocity.

No different that a small valve small port SBC and a big valve big port SBC should want around the same velocity.

Stan
by Stan Weiss
Wed Apr 22, 2020 4:04 pm
Forum: Engine Tech
Topic: Port length BBC heads
Replies: 6
Views: 486

Re: Port length BBC heads

These are from PipeMax / Larry Meaux Int=5.339 Exh=2.818 Int=135.6 Exh=71.58 GM #3890462 SBC out-the-box shape 1.940-1.500 Int=5.975 Exh=3.380 Int=151.8 Exh=85.85 GM 781 BBC cast-iron Good-Port in ported shape Int=5.820 Exh=3.380 Int=147.8 Exh=85.85 GM 781 BBC cast-iron Bad-Port in ported shape Stan
by Stan Weiss
Thu Apr 16, 2020 3:48 pm
Forum: Engine Tech
Topic: How fast can a 400 sbc go?
Replies: 24
Views: 1251

Re: How fast can a 400 sbc go?

Say in a 3300lb bracket car turbo 350 4k stall 456 gears 10/28 slick? Must run a solid flat tappet any intake or carb. Any racing fuel or E85. about 12/1 comp. :D How fast will 850hp push a 3,300# car ? Take an old SB2 NASCAR Cup engine, and add stroke, to get to 400" You wouldn't even need to chan...
by Stan Weiss
Wed Apr 15, 2020 10:45 am
Forum: Engine Tech
Topic: Mushroom Flat Tappets/Tappet Weight
Replies: 55
Views: 1488

Re: Mushroom Flat Tappets/Tappet Weight

My point being that if the mushroom and bucket diameter is the same they still have the same max velocity limit. I was looking for Mike to join in because I don't know if on the bucket one might be able to use a higher acceleration. Stan Right, they do. I thought this was interesting... Here are so...
by Stan Weiss
Tue Apr 14, 2020 2:55 pm
Forum: Engine Tech
Topic: Mushroom Flat Tappets/Tappet Weight
Replies: 55
Views: 1488

Re: Mushroom Flat Tappets/Tappet Weight

My point being that if the mushroom and bucket diameter is the same they still have the same max velocity limit. I was looking for Mike to join in because I don't know if on the bucket one might be able to use a higher acceleration. Stan Right, they do. I thought this was interesting... Generally s...