I greatly appreciate your input on this given the respect you seem to have on the forums. Not that I am prepared or interested in changing the cam,....what are you thoughts on my cam selection, and if I wanted more low end torque, what cam specs should be looking for?

 

Ohhh. You've gone and done it now, opened the can of worms in Pandora's box in the roller coaster even...hahaha.
Gross=hp and torque at the crank, no accessories,1 no drive train, just the engine, no air cleaner, dyno headers or exhaust.
Net= hp and tq with accessories attached such as ps pump, alternator, water pump, air cleaner, smog pump and stock exhaust.
Rwhp= power exhibited through the drive train at the rear tire.

Here's were I get confused, i have a 78 manual kinda like a Chilton that says the 180 horse was through the tranny, others say this isn't the case, I don't know for sure.

 

There is power to be had in camshaft change but I dont' feel the cost justify's it. I would not spend the money.

This thing should have plenty of grunt. I feel you have a fuel or ignition issue that is making it lazy. I would check and recheck all fuel and ignition stuff.

 

The AFRs have a good I/E ratio.
I'm told they do not need a dual pattern cam w/good exhaust.
How much would be picked up w/224-224 and 1.6 RRs?

I wonder?

R

 

Duration is the ability to sustain power at a given rpm range. So how long you hold the valve open is dictated by the demand created by piston speed. Piston speed is stroke and rpm range.

I cam for average power under the curve. Camming to make peak power at 6500 rpm then you drive the car at an average of 3500 is not going to be a good running street car.

So to answer you question....yes because of the AFR's high I/E ratio the duration at .050" is best if the same. The 224 with 1.6 would be best for a 350 wanting peak power around 6300 rpm.

 

They were discussing engine formulas over on YB. Here is the formula you can use to compare cam specs and what kind of airflow you will need to feed a given CID to rpm.


I have a calculator on my web site based on some of Chris's writtings

Estimate Cam Intake Duration @ 0.050" Needed

Engine Size = 540ci -- Number of Cylinders = 8 -- Max RPM = 6000
Volumetric Efficiency = 100% -- Head Flow - Intake CFM = 324.52

The result of your calculation is:

260 Duration @ 0.050" Lift



Special Thanks to Chris Straub - Straub Technologies


Stan
__________________
Stan Weiss / World Wide Enterprises
Do you use engine simulation software that uses cylinder head flow files?
We have a package of more than 2950 DFW or FLW Files.
http://www.erols.com/srweiss/index.html
Offering Performance Software Since 1987

 

I believe you may have been happy if the cam had been smaller , a single pattern, and a tighter lobe separation too. The Ramjet 350 is rated at 400 tq @ 3,500 rpm with 196* intake duration, and 350 hp @ 5,000.

Interested to see how you feel after the next drive or two !?

 

The Chevy zz4 engine is 355hp, with this setup:

These Chevrolet Performance ZZ4 350 C.I.D. 355 hp turn key crate engines include all of the necessary parts to get your engine running. With over 405 ft.-lbs. of torque, the ZZ4s are the best way to put an aluminum head, 4-bolt main block, roller cam, high performance small block between your favorite fenders. The aluminum angle-plug cylinder heads have screw-in rocker studs, 1.94 in. intake and 1.50 in. exhaust valves, and 58cc combustion chambers that yield a crisp and responsive 10:1 compression ratio. Also included are lightweight valve spring retainers, radiused valve seats, and valve stem seals to help keep the oil where it belongs. To complement the cylinder head design, we've incorporated a billet steel hydraulic roller tappet camshaft with a .474 in. intake and .510 in. exhaust valve lift. The combination makes 355 hp at 5,250 rpm and has that great-sounding musclecar idle, with just enough lope to let people know that these are no station wagon engines.

Additional features include:

* HEI distributor with an ignition timing advance curve developed for performance
* Spark plugs and wire set
* Dual-plane aluminum intake manifold
* Holley 770 cfm carburetor
* Chrome air cleaner kit
* Fuel pump
* 8 in. harmonic balancer
* 12.75 in. automatic transmission flexplate
* Starter
* Cast iron water pump
* Serpentine accessory drive pulley system for air-conditioned applications

 

Even though the engine will probably run the strongest above 3000 rpm, you should have plenty of torque at lower RPM to have some fun with. The one thing I can see with your setup while running below 3500 RPM is with the Quadrajet you may still be on only the primary side of the carb, which has a very small CFM rating with double or triple venturies (can't remember anymore), for good gas milage and not performance. You may not see the engines real potential until you get those large secondaries to open up. Use to run a Quadrajet on a BB Olds engine years ago, and when those large secondaries would kick in you could definitely feel it.

Just for comparison. You have larger heads and I have a bit larger camshaft:
- New GM ZZ4 short block
Same
- AFR 180cc Heads, 65cc Chamber 10:1 Compression (015 gasket)
ZZ4 (L98) Heads, 165cc, 58cc Chamber, Manley Race Flow Valves & Springs
- GM Factory Hydraulic Roller Lifter system
Same with AFR "rev kit"
- Comp Cam Extreme Energy XR270 Roller Cam (218/224, .500 lift, 110 LSA)
GM's LT4 "Hot Cam" (218/228, .525 lift, 112 LSA)
- Comp Cam Ultra Pro Magnum Steel Roller Rockers
Crower 1.6 Roller Rockers
- Edelbrock RPM intake
ZZ4 dual plane intake with 1/2" 4-hole spacer
- Quadrajet rebuilt by Lars (with the above engine specs)
Demon (Holley style) mechanical 4 barrel
- DUI Performance HEI Distributor (timed to 35 degrees)
GM HEI with MSD coil, recurved, and adjustable vacuum advance
- Stainless Works 1-5/8 inch long tube headers / 2-1/2 mandrel bent exhaust system
1-5/8 long tube headers and dual exhaust
- Borg T-10 Rebuilt Original 4-speed transmission with 3:55 differential; New Spec Stage II Clutch
Richmond 5 speed transmission, aluminum flywheel, dual friction clutch, 3.08 gear

Here is my chassis dyno pull (328 RWHP & 350 Tq). Blue line I was running lean so I quite early and rejetted the carb. Everybody disagrees with what exactly chassis dyno numbers mean since different brands/operators will produce different numbers, but they are great tuning tools so I definitely recommend spending some time on one.

It has more torque above 3k, but even at 2k the torque isn't horrible so if your engine is anything like mine it should be fun to drive. Important thing is it took some tuning on the carb and ignition to get the engine to run good. At first it was a bit lazy too.



Also, here is my 1/4 mile running on true street tires. Not extremely fast, but it can hold its own against most street cars. I have no complaints about its performance and I built this engine ~15 years ago. Note that to achieve this time I shift at 6500 rpm and the engine doesn't drop below 3000 rpm during the run.

60' 1.922
330' 5.381
1/8 8.27 @ 85.5 mph
1000' 10.744
1/4 12.8 @108 mph

Good luck getting her tuned correctly, your setup should be fun to drive when you get it sorted out.

 

I guess that all these motors we have put together LS3 and LS4 are poor performers according to Chris Straub. We have been using @ 330 cfm heads and the following cams. That is the flow of like a AFR 227 cc head

Trying to find a camshaft for your LS-Series based engine? Livernois Motorsports has a cam for your application.

Livernois Motorsports Stage 2 LS-Series camshaft is recommended for mild street vehicles. It works excellent with our CNC cylinder heads and produces good power while still maintaining a decent idle and good drivability.



Duration 232@.050

Lift .595"

LSA 114

 

Interesting company that i came across when trying to figure out a 425 ci stroker LS4 cam with FAST FI. I ended up with something nearly identical to my Vette 427 SBC only this motor went in an off road racing machine, all at their advice. This is just one of many companies out there.

http://www.livernoismotorsports.com/

 

That's pretty impressive with 3.08 gears. What MPG are you getting?

 

I doesn't get bad mpg, but I don't have an exact number for you. Last time I checked it was in the mid teens, but I haven't driven it much on the highway lately. Have taken it down to Bowling Green (3 hrs away) before, but it's been a few years.

 

that is NET HP ..engine on a dyno with accessories installed.. GM changed from Gross HP , which is just engine , to Net in 1972... RWHP will be substantially less . Hope that clears things up for you

 

I asked the question, but already knew the answer. So, point is this, when people talk about HP, and when car manufacturers claim HP, and torque as well, they are talking about ENGINE ON A DYNO HP AND TORQUE, NOT rear wheel horsepower. We all know that, and so therefore to bring up rear wheel HP as a measurement is to compare apples with oranges to makes some invalid point. Whatever the actual rear wheel HP is, its relative to the engine dyno HP minus the transmission and driveline losses, and that number itself means nothing, except when you are unfairly comparing apples and oranges. A 400 HP rating on an engine dyno will produce more Rear Wheel HP than an engine producing 180 HP on an engine dyno, and its relatively lower number. Its all proportional, and simple math.

So, my 1977 Corvette advertised 180 HP as an L48 option. If I am to believe the majority of people who I respect on this forum, if I believe the desktop dynos I have entered components in to, and if I believe everything I have read in many books on the expected HP and Torque I should get out of the components I have chosen, IF I produce 360 HP, I have doubled it! If it makes 400 HP like many believe, its impressive, and a great improvement over stock. Arbitrary numbers really mean very little to me, even though the American white boy in me likes to hear big numbers.

 

Another chest thumper....HAHAHA. I looked at it the same way you do when I did.top end on the L48, if you make 280 horse at the drive shaft yoke, then you've respectfully added a soldI'd 100 horse if to hit 400 gross, that would put you in the 330ish at the drive shaft yoke, that's putting 150 more horse out, very respectable and you shouldn't have any issues noticing 120 to 150 more horse. Now would you quit talking, get out and punish that f***er some so we can you can spot that extra power.

 

 

The formula is a guide line to get one close to what they will need camshaft and keep them out of left field. Same math I use everyday and my customers results speak volumes about how it works.

 

You guys are way beyond me.

If a 218-224 is too small and revs to 5500 or so.
How does adding 6* of intake make it rev to 6300?
I would think it would add 200-300 rpm to HP peak?

Shows what I don't know.
I'm still running the restrictive 2" RHs.
I can't wait to see what the 2.5" RHs will make?

R

 

Fair enough what are your calculations for a 4.155 X 4.00 1 7/8th X 28 headers 3 inch exhaust. single plane. presently set up for .700+ lift, but I'm not adverse to trying a h-roller if I can have a 7000 rpm red line. Wet weight at 3000 lbs and 5 speed man. 4.11 rearend.

head flow:

.200 .300 .400 .500 .550 .600 .650 .700
Int 148 210 261 296 304 312 315 318
Exh 114 162 204 220 225 229 233 237