first hotrod build

[Grumpy]

yes that looks good,
but until you test it you won,t be certain as to what the result will be!
yes ID put a drop or two of silicon gasket sealant on the internal edge of the plenum divider to intake plenum, temporarily locking it in place for testing,
to make it easy to remove but not prone to vibrating

http://garage.grumpysperformance.co...ol-plenum-intake-divider-fix.5022/#post-14140

 

[hotrod coupe]

looking around all I have found for fuel pickups are 1/4" npt nothing larger, they have -6 -8 -10 an fittings that fit 1/4" pickups but this seems to me to be defeating the purpose. Tanks has 1000 hp systems using 1/4" fittings, am I missing something or should I just get a blank and drill and tap to make a proper pickup. I would think the market would supply correct size pickups for the need.

 

[Indycars]

Pictures of the situation would help!

I'm not sure where these 1/4 inch fitting are located.

 

[hotrod coupe]

the round six screw pickup plate on the gas tank it has pickup, return and breather tube. will post a picture later as soon as I can.

 

[Grumpy]

• theres three seperate sets of Smilies
• Skype Smilies (New)
• Emoji Human (has the thumbs up icon/smillie

 

[Indycars]

Why mess around with one of those little tiny thumbs up when you can go whole hog ! hehehe!!!

 

[hotrod coupe]

It has been written that all AN fittings do not have the same inside diameter passage, seems to defeat the purpose of standardized fittings 6-AN should be 3/8, but such is the nature of business. What brand has the largest inside diameter fittings.

 

[Loves302Chevy]

I just used some Jegs copies of Russel's Endura fittings. The ID of those was correct.

 

[hotrod coupe]

which is a more realistic representation on dd 2000, seat to seat or @ .050. Put in my cam specs both ways and got two completely different graphs. Cam is a howards hydraulic roller 272/278 advertised 219/225@.050. Is one way or the other correct or an average of the two?

 

[Grumpy]

just add 15 degrees to the .050 timing figures to get approximately at effective seat to seat timing and use that to calculate
yes adding 30 degrees would be closer to seat to seat, but most calculators are built to compensate
there's almost no effective meaningful, air flow in the first .015 of valve lift off the valves seat.
remember even at a 750 rpm idle the engine goes through a 720 degree cycle and the valve opens and closes more than 6 times a second, the air flow that can occure between the seat and .015-.02 lift is almost meaningless to the power curve, and it becomes less critical at 7000 rpm where the valve cycles over 58 times a second from seat to seat.

(one reason many older cam companies listed .020 lift and .050 lift timing)

example lets say you used this spec card

it shows the timing at .004 (EFFECTIVELY SEAT TOO SEAT)
use that if its available


the spec card timing at .050 shows
intake opens 8.0 BTDC and CLOSES at 42 degrees ABDC
EXHAUST .../56 BBDC and closes at 2 degrees ATDC

adding 15 degrees you get
intake opens 22.0 BTDC and CLOSES at 57 degrees ABDC
EXHAUST .../71 BBDC and closes at 17 degrees ATDC

using the modified .050 timing, adding the extra 15 degrees at each point,
the calculated power curve will be rather similar to the .004 calcs used in most cases

 

[Indycars]

which is a more realistic representation on dd 2000, seat to seat or @ .050. Put in my cam specs both ways and got two completely different graphs. Cam is a howards hydraulic roller 272/278 advertised 219/225@.050. Is one way or the other correct or an average of the two?

If you have the cam card with the valve timing, I can run a simulation in DynoSim5. It uses both
seat-to-seat and @.050 duration to make the calculation. I will also need ......
CID
Heads with flow numbers
SCR
Intake Manifold Model
Header Tube Diameter

 

[hotrod coupe]

383 cu sbc,
afr 210 intake flow
.200-145
.300-199
.400-255
.500-292
.550-301
.600-309

exh .
200-110
.300-158
.400-192
.500-210
.550-214
.600-220
scr 9.86
intake manifold edlebrock air gap rpm with a 2" four hole spacer and a 2" 2 hole divided spacer for 4" total
not sure if I will use my edlebrock performer 600 to start but plan for a 750 holley style carb sprint style headers 1.75" primarys with 3" collectors and glasspack mufflers.

 

[Grumpy]

I looked back several pages and did not see the compression ratio listed??
is it still the 9.63:1 static compression ratio, you listed as we started with in this thread?

 

[Indycars]

Sorry, when I looked back you wanted to start with a 600 cfm carb, but I used the 750. Don't think
there will be more than a 10 HP difference at higher RPMs.

You didn't specify what cam, so I used the Crane 119661 above. I can always run another simulation
with a different cam whenever you need.

 

[hotrod coupe]

cam specs are 110 lsa advertised duration 270.6 in 276.6 ex @.050 219 in 225 ex sorry was in a rush and forgot to put it in. considerably smaller cam. static compression by Wallace calculator is 9.86

 

[Indycars]

Sorry, I should have been more explicit about the cam specs.

I also need all 8 valve timing events at both Seat-To-Seat and at .050 Lift. Such as
Intake Valve Closing(IVC) = 69° (Seat to Seat).

I will use the above specs along with valve timing events to get the best possible simulation.
Some times I can back into some of the numbers when I have the cam card. I searched
owards and the internet, but could not find their cam cards.

Have you looked at the DCR lately with the Howards cam above using the actual IVC to
make sure you are still on the right track?

 

[hotrod coupe]

Wallace calculator says 7.99 dcr. seat to seat ivo 27.3 btdc ivc 63.3 abdc evo 70.3 bbdc evc 26.3 atdc @.050 ivo .5 atdc ivc 37.5 abdc evo 45 bbdc evc 1 atdc these figures are with the cam advanced 2 degrees. After reading on dcr I thought just under 8 would be good for street gas with .046 quench, am I wrong here.

 

[Grumpy]

a dcr of 7.99 and a .046 quench ,should be fine (if your calcs are correct)

 

[Indycars]

Your duration or timing number don't exactly agree, something is off by 1 degree. Shouldn't
make any noticeable difference thou.

I kept the Crane camshaft on the graph for comparison, thought it would be interesting to
see the difference.


.

 

[hotrod coupe]

Thanks for running my build, its nice to have some verification on what I have deduced. Top hp is down a bit in rpm from what I was shooting for 5500 instead of 6000 and torque is flatter at 2500-4500 I think I will be very happy with this and will have a good time learning to handle it. What is the prevailing opinion on edlebrock performer carbs compared to holley style.