Roller Camshaft Rpm Range

[aaronk785]

I was in a bind and purchased a wells ecu to get me home. It wouldn’t rev above 4500 rpm. Replaced it with an orange box and problem gone.

 

[Bewy]

The original Holley book list flow rates for various fuel pressures & n/seat sizes. 0.110" n/s 153 @ psi, & 230 @4 psi. For 3.5 psi, 200 would be a reasonable guess. 200 is lbs/hr which is 67 gph for two n/seat. 4bbls have two n/seats. A 500 hp engine requires 42 gph..

 

[MOPAROFFICIAL]

What do you guys think about the Mancini Orange Box they sell? Right now I have a generic auto parts ECU.

MRE - Orange Ignition Control Unit

Skip the orange ignition box and get an MSD ignition control unit. The Orange Box spark dwell goes to **** after 5500 RPM or so

 

[Slantsix64]

Guys check out these two time slips. The one to the left is at a 1/8 mile track with a 600 cfm Holley, and the one to the right is the quarter mile track with a 3310 750cfm Holley. Everything else is the same on the tune, just carb swap.

 

[Slantsix64]

Looks like the 600cfm carb had better 60ft times 330ft and a better 660 vs the 750 3310

 

[junkyardhero]

Looks like the 600cfm carb had better 60ft times 330ft and a better 660 vs the 750 3310

that's pretty typical without any additional tuning. a slice of ham says that the 600 runs out of breath before the stripe in the 1/4

though, the 60' times should be darn near identical

 

[Slantsix64]

Guys i'm an idiot.... The issue has been solved. The reason i why couldn't pull past 5100 RPMS, was that 1/4 lawn mower filter before the carb lol.

I can Pull up to 6500RPMs and i can tell it's still making power. No Backfire no popping.

Just bought a 3/8 Fuel filter and BAM she rips!

Now i'll have to wait until December to see what she will run. I had that filter on both Carbs on both of those time slips lol

 

[Slantsix64]

Honestly you couldn't tell the filter had a 1/4 outlet because it had both 1/4 and 5/16 line diameters.

 

[Slantsix64]

 

[273]

At least it's a cheap fix

 

[MOPAROFFICIAL]

Looks like the 600cfm carb had better 60ft times 330ft and a better 660 vs the 750 3310

That's to be expected with the smaller carb. When testing is 650 CFM double pump against a 750 CFM the bottom was crisper and snappier but fell off after 6,000 RPM as to where the 750 pulled a harder mid-range and top end to about 6800+. Basically, the 750 pulled harder at 4500+ over the 650 on my 340.

 

[crackedback]

Got to feed it.

 

[TT5.9mag]

Guys i'm an idiot.... The issue has been solved. The reason i why couldn't pull past 5100 RPMS, was that 1/4 lawn mower filter before the carb lol.

I can Pull up to 6500RPMs and i can tell it's still making power. No Backfire no popping.

Just bought a 3/8 Fuel filter and BAM she rips!

Now i'll have to wait until December to see what she will run. I had that filter on both Carbs on both of those time slips lol

Na you ain’t an idiot. You learned something. An idiot uses the lawnmower filter again on his next project.

 

[aaronk785]

I’ve never had any luck with the Holley 3310 carbs. 650 and 750 do always worked better.

 

[crackedback]

Always had good luck with 3310's. Put a lighter spring in them with a secondary block and run em.

Had Low 12's streeters run them. Do I prefer DP carbs... yep!

Just cause it will spin 6500 doesn't mean it will be faster shifting up there. I'd do the stagger step, 5800,6000, 6200, 6400 and if at a 1/4, leg it out the back wherever it traps. You'll find the sweet spot.

 

[Slantsix64]

now don't jinx me lol

 

[Slantsix64]

Na you ain’t an idiot. You learned something. An idiot uses the lawnmower filter again on his next project.

now don't jinx me lol

 

[Dart Frog]

In my experience it's easy to over carb a car with high gears. a light car with high gears will respond much better to more carb especially if it has manual secondaries.

 

[crackedback]

might like a couple more degrees of total timing

 

[Slantsix64]

might like a couple more degrees of total timing

i am at 12 initial and 18 mechanical right now. 30 degrees total. if i bump up the initial to 15 it will detonate at WOT.

this is with the curving coming all in at 2800rpms

 

[crackedback]

Might run a bit different now that the fuel delivery issue looks to be solved. I was thinking 32 total.

Maybe slowing the curve down might help too. Only know by testing to find out.

Definitely going to run better.

 

[340sFastback]

Good thread. Now rest of know don't put a 1/4 inch lawn mower gas filter on our cars.

 

[Bewy]

If you increase the initial timing, then you need to decrease the total timing by the same amount. That is done by internally modifying the dist. Failure to do this will result in detonation...

 

[MopaR&D]

Good thread. Now rest of know don't put a 1/4 inch lawn mower gas filter on our cars.

Putting any kind of fuel filter (aside from the factory in-tank "sock" filter) upstream of an OE-type mech fuel pump can cause starvation issues, had it happen on my D200. Wasn't easy to find as a PO stuck it in the frame rail partially hidden, once I took it out no more starving for fuel under heavy throttle/high RPM.

OP might want to now revisit making ignition timing adjustments as the fuel starvation may have caused a lean condition at WOT prior to the engine cutting out which will also cause detonation. Too lean > slow/inconsistent combustion > increased heat rejection > ping city

 

[gzig5]

Na you ain’t an idiot. You learned something. An idiot uses the lawnmower filter again on his next project.

Agreed. And a clever fellow donates the lawnmower filter to the Ford/Chevy guy a couple pit stalls over.