Custom Grind or Off the Shelf

[Challenger340]

just curious here.... so humor me OK ?

But how are you guys running any Computer Engine Sims for Cam selections without real Cylinder Head Flow Data ? recorded Intake./Exhaust ratios through the HP Manifolds/Pipe etc..... you know, a true 'wave' factor instead of "fill & dump" or by guess by golly ?

Any Output..... being only as good as "imputs" obviously here ?
I mean for the 'restricted' applications, it's a whole different negative pressure scavenging cycle and it takes us forever on our SF750 Bench to get Head Data we're confident in for our sims on restricted Hillborn Sprints/Circle Track bozo's etc.

Just say'in,
the only other way I know to do it ?
is to access someone with a TON of experience in BB Mopar pressure scavenging cycle applications.... like Dwayne Porter or maybe Bob K.
Actual trial and error testing experience being absolutely the BEST !

 

[wyrmrider]

great post Dodge
someone else made the torque Asymetrical suggestion
Bullet recommended .904 symetrical lobes in 2020 but I do not know which Bullet lobes are endurance and which are agressive
Have to work with stock rockers here
go figure
they might work with Rhodes lifters
Jones are .842 lifters - I trust jones seat timing
I usually do not want to give up 20 foot lbs of torque- all the converter/ gear changes required
If not I do not thnk they would make the targer 165 lbs cranking
A race applicacation can give up some or a lot of low end under 3000
but street/ strip?
DC cams were designed for his combo -or Engle, Crane or Racer Brown
The Lunati works
I'd first ask Howard if they coud but a different exhaust with their Mopar lobe
something with the same or less duration (maybe a FORD lobe...shhhh)
My Jones Mopar intake lobe uses a chevy exhaust (shhh) matched to ported head flows, stock rockers and manifolds and 9:1 compression. It worked out to 112 LSA but that was a result of the seat timing not an "Given" input






brown have a good shot

 

[Challenger340]

How are you guys running computer cam sims ?

Off WHAT Head Flow Data ?.... especially for the restricted/hp manifolds stuff within the constrained scavenging cycle ? and HOW are you testing the Final results ?
Engine Dyno ?

 

[Curiousyellow71]

Just curious, how bad would the MP 280 .474 cam be? 230ish?, 110* 60* overlap.

MP 280 is 238/238

Pretty spirited idle yet, especially in a 383.
In a 71 challenger we put MP 280 .474 in a 68 440, rerung / iron dual plane 3.23 stock 1600 stall, 1 3/4 headers, 906 pocket porting and probably 9.3:1...pretty rough idle yet. 13.7@99. It was a big enough cam that it liked more gear and stall. Which was done later 2500 and 3.90...probably high 12s. Went to the track but starved for gas had a 1.80 60' from what I recall never made a full pass before the motor was pulled.
I would call MP280 a street/strip cam. In a 383 w exhaust manifold and 516s its giving up bottom end and I think you would be disappointed on top end... I would have tried it 25-30 years ago Lol, nowadays you should be able to get a better cam that doesn't sacrifice the torque and makes near the same hp.

 

[LowDeck451]

MP 280 is 238/238

Pretty spirited idle yet, especially in a 383.
In a 71 challenger we put MP 280 .474 in a 68 440, rerung / iron dual plane 3.23 stock 1600 stall, 1 3/4 headers, 906 pocket porting and probably 9.3:1...pretty rough idle yet. 13.7@99. It was a big enough cam that it liked more gear and stall. Which was done later 2500 and 3.90...probably high 12s. Went to the track but starved for gas had a 1.80 60' from what I recall never made a full pass before the motor was pulled.
I would call MP280 a street/strip cam. In a 383 w exhaust manifold and 516s its giving up bottom end and I think you would be disappointed on top end... I would have tried it 25-30 years ago Lol, nowadays you should be able to get a better cam that doesn't sacrifice the torque and makes near the same hp.

Well, you get 238 when you use MPs method of multiplying adv by .85, which I always heard is too much and that they are closer to 230. I mean, 238 from a 280 - semi fast rate lobe? - does sound like a lot doesn’t it?

 

[Curiousyellow71]

We recently checked a 284..it was dead on .85. being around the MP 474 I would say .85 is pretty close. But it is true...MP cams are not what they once were so it's hard say. I doubt the same cam grinder does them now as the one we measured.
There is a generic 280 .480 Chevy lifter cam it is 230. MP 280 lopes a lot more. We have run both, I would be pretty disappointed if they replaced the .474 cam w the generic 280 .480.

 

[LowDeck451]

We recently checked a 284..it was dead on .85. being around the MP 474 I would say .85 is pretty close. But it is true...MP cams are not what they once were so it's hard say. I doubt the same cam grinder does them now as the one we measured.
There is a generic 280 .480 Chevy lifter cam it is 230. MP 280 lopes a lot more. We have run both, I would be pretty disappointed if they replaced the .474 cam w the generic 280 .480.

Ok, I just remember reading that years ago. Mentioned that cam because some of the lobes talked about here are 280. One common thread I’m seeing is 112 is too much for a 383 with manifolds, and Jim said this also. The MP 280 is on 110 which is why I asked about it. Thanks

 

[wyrmrider]

with 112 you need a little more compression than 110
108 with manifolds on a 383 not me on the street
does get the intake closed earlier but you can do that with duration
110 ok
112 with a Howard or Lunati type ramp
forget the .050
I can vary the seat timing by 20 degrees with the same .050
also sorta forget LCA
draw a big circle and plot the intake close points
pick one that's going to give you the Dynamic Compression you need- say 165
Work back around to the Intake Open And Exhaust that's not going to give you a lot off reversion
An Intake opening that's going to track the piston demand with your rod ratio
note that the piston has more dwell than a SBC so you do not have to open as early or jerk open so fast (but not as much as a 440)
a lot of open at max intake flow for which the .200 duration is a proxy
Exhaust open to enhance expansion power while giving blowdown
note the piston is moving faster than a SBC so timing is more critical
Sim progams help here?
who has the best sym progam?

 

[Dodge Bros]

I totally agree the pressure waves are greatly disturbed by the manifolds and a computer sim falls pretty short there. I get uneasy pulling the LSA in and running more overlap with manifolds, even more so when adding compression. I use my computer sim for trends, that is it. I have files from heads we ported, plus files from other peoples heads, plus their is Stan Weiss’s head data base I pull from. I picked a head I thought would be fairly close on actual E/I ratio and looked for some trends. I have done enough cams to have an idea when the computer is blowing smoke at me. For certain there is no substitute for experience or track time. I think we did about 10 cams from Bullet last year, but also use other cams from other mfg’s too when we think they are a better fit. We have cams here from comp, Lunati, Crower, isky and cam motion. Never tried R. Brown, our machinist has had good luck with them. Especially with Hemi’s.

We greatly respect Bob K. and Porter. I enjoy doing cams and find the good and bad that comes with our own experience and testing. To me that stuff is fun.

 

[Challenger340]

I totally agree the pressure waves are greatly disturbed by the manifolds and a computer sim falls pretty short there. I get uneasy pulling the LSA in and running more overlap with manifolds, even more so when adding compression. I use my computer sim for trends, that is it. I have files from heads we ported, plus files from other peoples heads, plus their is Stan Weiss’s head data base I pull from. I picked a head I thought would be fairly close on actual E/I ratio and looked for some trends. I have done enough cams to have an idea when the computer is blowing smoke at me. For certain there is no substitute for experience or track time. I think we did about 10 cams from Bullet last year, but also use other cams from other mfg’s too when we think they are a better fit. We have cams here from comp, Lunati, Crower, isky and cam motion. Never tried R. Brown, our machinist has had good luck with them. Especially with Hemi’s.

We greatly respect Bob K. and Porter. I enjoy doing cams and find the good and bad that comes with our own experience and testing. To me that stuff is fun.

I had to ask.... because, well.... we've seen some real supposedly 'hitter' grinds from some of the best you mentioned on the Dyno.... Bullet, LSM, etc.,... sometimes even long after they've been swapped into Engines with absolutely GLOWING "seat of the pants' reviews from the Owners ?
Some are even quite comical ?
Especially when you have recorded 'baseline' runs on the Dyno for the Engine......
Buddy gets talked into.... purchases.... they swaps in the "magic" Camshaft..... runs it.... GLOWING results !!!!!!!!!!!!!!!!!
He then brings the Engine back to the Dyno.... we even Dyno'd FREE OF CHARGE ????????????? because obviously we were just as curious ?
Only to verify it was down 22hp and 31 Ft/Lbs on peaks with 'averages' across the curves similarly down 7 and 9 from his former OOTB Cam ?

All I am saying is this....
without hard factual data ....
1.) output can only be as good as the imput for any computer Cam profile simulation
and
2.) without actual Engine Dynomometer testing to backup results ? advancing the R & D profile can be extremely difficult.

 

[Challenger340]

with 112 you need a little more compression than 110
108 with manifolds on a 383 not me on the street
does get the intake closed earlier but you can do that with duration
110 ok
112 with a Howard or Lunati type ramp
forget the .050
I can vary the seat timing by 20 degrees with the same .050
also sorta forget LCA
draw a big circle and plot the intake close points
pick one that's going to give you the Dynamic Compression you need- say 165
Work back around to the Intake Open And Exhaust that's not going to give you a lot off reversion
An Intake opening that's going to track the piston demand with your rod ratio
note that the piston has more dwell than a SBC so you do not have to open as early or jerk open so fast (but not as much as a 440)
a lot of open at max intake flow for which the .200 duration is a proxy
Exhaust open to enhance expansion power while giving blowdown
note the piston is moving faster than a SBC so timing is more critical
Sim progams help here?
who has the best sym progam?

We started with Dynomation many years ago... Version 6 still works reasonably well, albeit, insufficient thermodynamics across the wider combustion spectrum on benzene ring fuels(temperature heat sink).... still good on Hydroxyl group stuff though as cooler.

 

[Dodge Bros]

I agree with Wrmrider, Jmho, I would not go narrower than 110 lsa either. Before I went to a 108 lsa I would advance the cam some. That should increase the cylinder pressure and scavenging some, and opening the exhaust a little earlier to help the top end power with the manifolds.

Common consensus is the 383 should not want a wider lsa because of the short stroke. Pure stock guys seem to have decent result running the 383s on a 112-114 lsa though. The weak link on a pure stock 383 is probably more the smaller asv carb more so than the wider lsa. The pure stock guys could pull the LSA in if would help, as fair as I know changing the LSA is with in the rules if they can pull enough vacuum. They seem to have have the LSA out toward 114 yet and move the cam timing around to make max power.

Dynomation 6 and the Performance Trends Simulators are both pretty powerful sim programs. Most the guys I know of have Compcams files for the Dynomation program, but do not have other profiles for other cam brands unless they were files from a cam DR.

 

[POMONAMISSEL]

you mean a cheater cam like the stokers ran , that would be a custom grind for your car n driving style . my bud here in san jose can grind you want you need . [email protected] , spiro jannings owner operator 408-292-0646 .

 

[Curiousyellow71]

All I am saying is this....
without hard factual data ....
1.) output can only be as good as the imput for any computer Cam profile simulation
and
2.) without actual Engine Dynomometer testing to backup results ? advancing the R & D profile can be extremely difficult.

Good points.
I would say the most basic sim is helpful to keep from picking the wrong cam for the average Joe. Coming up with input to feed everything in a complex program such as dynomation is a undertaking. You almost have to work backwards from the dyno to get some of the input.

albeit, insufficient thermodynamics across the wider combustion spectrum on benzene ring fuels(temperature heat sink).... still good on Hydroxyl group stuff though as cooler.

Could you explain that it a bit...are you saying dynomation was more accurate for alcohol sims then gas sims w current gas additives? I had to take thermodynamics being a engineer..but that went right over my head. Lol...

 

[wyrmrider]

I did not see anyone address your 280 MP question
OOPS I missed a page
280 Mopar cam would be like a 284 or larger comp as far as duration goes
the lift is ok but you would be bleading a lot of low end off for a street build
As Far as our friend Porter
he could pick a cam but he uses comp to grind his cams and I do not see comp having anything shorter than 274HL as a Mopar lobe
would still be interesting to see what he says

I did see where someone got a semi custom Howard for $150 a few years ago
use the intake we were discussing and a Ford or Chevy master on the exhaust
Did I already post this?
Street cam with some strip I like jones timing
and BTW he has a very good or the best simulator
started by his dad and a version was sold by brother Rick as "Controlled Induction"
currently under redevelopment

 

[LowDeck451]

I did not see anyone address your 280 MP question
280 Mopar cam would be like a 284 or larger comp as far as duration goes
the lift is ok but you would be bleading a lot of low end off for a street build
As Far as our friend Porter
he could pick a cam but he uses comp to grind his cams and I do not see comp having anything shorter than 274HL as a Mopar lobe

I did see where someone got a semi custom Howard for $15 a few years ago
use the intake we were discussing and a Ford or Chevy master on the exhaust
Did I already post this?

Yeah, curiousyellow71 answered my MP 280 question. Yeah you mentioned Howard’s and a couple different lobes but again, I’m just not ready to pick my own lobes.

 

[wyrmrider]

I'd see if howards would play ball using jones seat timing -get a quote
if not get the Lunati
I hope you hear from Jim at racer brown
I'm not impressed with bullet recommending symetrical lobes
One of the engles is also a long wearing safe choice for your combo
cheers

 

[m79ded]

@LowDeck451 Just an opinion bud I would like to help.I see this post is getting very technical with a tremendous wealth of Knowledge from many members. I must say that from your original request for a 383 with mild gears street driven and stock rocker gear i've tried 3 different cams that caught me attention and would work really good for you. I assume that you aren't in a class like F.A.S T that's requiring every ounce of power so street manners are important to you

1)Lunati voodoo cam Advertised Duration (Int/Exh): 262/268; Duration @ .050 (Int/Exh): 220/226; Gross Valve Lift (Int/Exh): .475/.494; LSA/ICL: 112/108; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 1400-5800;
2)Crower cam INT/EXH - Dur @ .050” Lift: 222°/234° RR: 1.5/1.5 Gross Lift: .486”/.496” LSA: 112° RPM: 1800 to 6000 Redline: 6500
3) Howards Lift: .518 / .543, Duration @ .050: 224 / 234, LSA: 112, Fair idle, Hot street & mild bracket racing, Strong mid-range.

I like all 3 for your case I mentioned the Howards in an earlier comment and you were concerned with lift on stock rockers. Fine I hear you and given that I would do the Crower and you'll be very happy. If more vacuum is required for brakes do the Lunati cam. The one that I didn't like it always kept coming short was the Comp cams 224-230, not liking that at all.

Hope it helps, Seen a few cars with mild hydraulics and these worked well and people were happy

 

[LowDeck451]

@LowDeck451 Just an opinion bud I would like to help.I see this post is getting very technical with a tremendous wealth of Knowledge from many members. I must say that from your original request for a 383 with mild gears street driven and stock rocker gear i've tried 3 different cams that caught me attention and would work really good for you. I assume that you aren't in a class like F.A.S T that's requiring every ounce of power so street manners are important to you

1)Lunati voodoo cam Advertised Duration (Int/Exh): 262/268; Duration @ .050 (Int/Exh): 220/226; Gross Valve Lift (Int/Exh): .475/.494; LSA/ICL: 112/108; Valve Lash (Int/Exh): Hyd/Hyd; RPM Range: 1400-5800;
2)Crower cam INT/EXH - Dur @ .050” Lift: 222°/234° RR: 1.5/1.5 Gross Lift: .486”/.496” LSA: 112° RPM: 1800 to 6000 Redline: 6500
3) Howards Lift: .518 / .543, Duration @ .050: 224 / 234, LSA: 112, Fair idle, Hot street & mild bracket racing, Strong mid-range.

I like all 3 for your case I mentioned the Howards in an earlier comment and you were concerned with lift on stock rockers. Fine I hear you and given that I would do the Crower and you'll be very happy. If more vacuum is required for brakes do the Lunati cam. The one that I didn't like it always kept coming short was the Comp cams 224-230, not liking that at all.

Hope it helps, Seen a few cars with mild hydraulics and these worked well and people were happy

Thanks. I do appreciate everyone’s knowledge and experience and yeah, a little over my pay grade at times lol. That Crower does keep coming up, on this thread and other 383 threads I’ve read. Jim at Racer Brown is the only one I’ve spoken to so far, but I do want to talk to others, easier to relay details and QnA rather than just a tech sheet. What I’m after with this car is pretty close to stock looking but runs quicker than it looks.

 

[383man]

3.55s are for a strip/street car around here. If you do any highway driving you will find that you are the slowest car on the road with those gears, unless you want to cruise in the 3 to 4 thousand, and maybe into the 5 grand RPM range.

Must be a very small tire. I run 4.30's with a 30" tall tire and cruise at 60-65 mph on the highway turning about 3200 rpm. Ron