For Carbs only=>
for an all-out max-effort DragRace engine
Max_Plenum_Entry_Area = (Int_Valve_OD ^2) *.7854 * 1.4
figure your Taper angle from that point to Valve
if your Total Induction Length is on verge of being too
short, then too much Taper will hurt overall ET
playing around with Taper...
What about the "Cost Efficiency"
i just had to replace the Alternator on my Daughter's
GEO Prism 4 cyl ..$300+ rebuilt $600+ new lifetime warranties both cases
if i drive a 10 mpg Suburban 15,000 miles @ $2 per gallon = $3000
if i drive a 30 mpg GeoPrism 4 cyl 15,000 miles @ 2 = $1000
a...
Another idea I DON'T like is when guys completely fill the oil pump with white grease or something similar. They do it so the pump will prime, but it restricts oil flow until it is completely flushed.--Pat
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i know that's probably not...
you can "rock" the crank back and forth slightly at TDC and more at BDC on a loose Piston-to-wall clearance engine
to read a better Leakdown percent ...can be as much as 8 or 10+ % differences.
what counts is the Blowby meter CFM
and what counts more or more often is "if" the Engine will make...
The mass of the air and fuel is the same going in and out.
The exhaust mass is the same as the intake mass, just hotter
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yes..thats what i also thought ?
i was Porting a pair of BBC heads for a College Student
and he was going for a...
a vacuum pump such as a Moroso 4-vane pump
http://www.maxracesoftware.com/Vac_Pump.jpg
would help out more and more as Engine has greater BlowBy , bad rod ratios, and large crank stroke
on engines with exceptional ring seal with 3 stroke ,very large oil pan, not a lot of gain with Vac-Pump...
Forgot to say the reson for this question. I performed a leakdown test with the pistons at B.D.C. and again at T.D.C., all 8 cyl. at B.D.C. were 2%, at T.D.C. 3 cyl. were 15% other 5 were 6-9%. --- 70MC
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but what's your "ring seal" when...
your Top -to Bottom ring seal/leakage should be the same any piston position in the bore..you shouldn't let the taper get more than .001"..and the out-of-round should be ZERO even if theres some taper top to bottom
looks like Torque-Plates might not have been used
or used with bolts ...also its...
>>why is it that small block comp drag race motors seem to usually respond to 16-1 & 17-1 compression ratios yet some competitive 500 c.i. pro stock motors I know of don't seem to net any gains past 15-1 to 15.5-1?<<<
Quote from Darin Morgan =>
The Pro stock engines are only 15 to 1 static...
Larry,
Thanks for the info. I checked out the spreadsheet to see the formulas involved and I have a question about the disch coef. The basic formula is FLOW/(CURTAIN AREA * 137.7). What is 137.7 for? a constant for something? Is this constant different depending on test pressure?--Rick...
A few questions, .. the curtain area at .300" how much will that flow?
what's the best possable?
also, .. I'm very bad at math, .. is there a spread sheet available to do the calc's, .. curtian area, .. etc.?
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Curtis, Darin Morgan has a Excel...
a Port has "zero velocity" with the Valve closed/seated
to make decent use of Port Velocity, you should have a Cam with at least .25 L/D Ratio and upwards to "get on the Port"
a small block Chevy head with 2.200 OD Intake valve and .310" stem diameter
Flow Test
Valve-----CFM----------Curtain...
>>>The velocity on the floor of the port along the short turn radius is 220 fps at 10 inches.<<<
if most of the entire Port floor's Short Turn apex area is at 220 fps at 10 inches of Test Pressure ....you are very close or already into Sonic Choke on a live engine and may already be seeing HP...
wwwRover2MGcom ...you can Simulate what your Car runs in the 1/4 Mile with this DragRacing Simulation at this Link
http://www.maxracesoftware.com/race_car_physics.htm
it will give you ET, MPH, GForces, etc every 10 Ft of distance
Larry Meaux (maxracesoftware@yahoo.com)
Meaux Racing Heads...
seat angle?
any experience with a 30º or 35º seat angle, ..
do they live, .. how long etc. ????
Curtis
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Pontiac and Oldsmobile used 30 deg seat/valve angles on a few OEM engines...i use to convert some these 30 deg to 45 angles for ET Bracket racing but that was with...
