Re: dyno time
[Re: dart9ss]
#3129989
03/16/23 08:49 PM
03/16/23 08:49 PM
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Joined: Jan 2003
Posts: 16,925 NC
440Jim
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made two pulls at 108 ,moved the cam -4 just to see what would happen So am I understanding this cam position right? Cam LSA 112 original pulls with intake lobe centerline 108 ATC, Then retarded the cam 4 degrees to 112 ATC ?
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Re: dyno time
[Re: fast68plymouth]
#3130001
03/16/23 09:42 PM
03/16/23 09:42 PM
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Joined: Jan 2003
Posts: 10,022 MN
JERICOGTX
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I’m waiting to see if anyone else picks up on it.
It jumped right off the sheet to me. BFSC is way low?
69 GTX
68 Road Runner
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Re: dyno time
[Re: fast68plymouth]
#3130018
03/16/23 10:44 PM
03/16/23 10:44 PM
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Joined: Mar 2006
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dvw
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I’m waiting to see if anyone else picks up on it.
It jumped right off the sheet to me. Am I seeing -4” to -4.5” of intake manifold vacuum? If so Something’s restricting the intake flow big time. Doug
Last edited by dvw; 03/16/23 10:47 PM.
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Re: dyno time
[Re: dvw]
#3130068
03/17/23 09:48 AM
03/17/23 09:48 AM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
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There are different parameters one can look at to evaluate the effectiveness of an engine combo.
On the dyno I’ve used for the past 26 years, the “better” combos, running on gasoline with a single carb........ have one of those parameters falling into a pretty narrow range most of the time.
For sure, all of the top BB Mopars I’ve tested that were built along the lines of the OP’s combo fall into that narrow range.
The results on Bob’s dyno sheet have that parameter pretty far outside what I would consider the “normal” range........ without there being any reason(in my mind) why it would be that much better.
AndyF’s 572 example, along with Jeff’s 563....... also fall right into what I consider the normal range.
That parameter? TQ/CI
Bob’s 529 is showing 1.465/ci........ which on the dyno here is extremely rare for a single carb on gas. The normal range for typical bracket race builds? Well, here they are normally in the 1.30-1.35 range.
I see nothing in Bob’s build that would indicate it would fall outside that window....... on the high side
So, this also falls into the “racing dynos” theme, which is why I stipulated that the numbers would look quite a bit different if the engine were tested here, with my dyno headers......... in the same way all the other “better” combos belted out 1.30-1.35 TQ/CI. Perhaps seeing 1.45+ TQ/CI isn’t that odd of an occurrence where Bob tested. But no single carb BBM has ever really gotten close to that on the dyno here.
If the TQ/CI number for Bobs 529 ended up at 1.35 here, the peak TQ number would be about 715 instead of in the 770’s.
Looking thru a pile of old dyno sheets, I only see one single carb BBM build that exceeded 1.35, which is a 14:1 572 with 440-1 cnc345’s on it...... and that one went 1.37. There are also quite a few sheets from pretty nice running combos, making what I feel is decent power....... that didn’t quite make it to 1.30.
Sure........”never say never”, but in my mind the chances of Bobs combo making 1.465 TQ/CI on the dyno here is solidly under 1%.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: dyno time
[Re: fast68plymouth]
#3130078
03/17/23 10:14 AM
03/17/23 10:14 AM
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Joined: Jan 2003
Posts: 4,048 Shelby Twp. Mi
HardcoreB
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There are different parameters one can look at to evaluate the effectiveness of an engine combo.
On the dyno I’ve used for the past 26 years, the “better” combos, running on gasoline with a single carb........ have one of those parameters falling into a pretty narrow range most of the time.
For sure, all the BB Mopars I’ve tested that were built along the lines of the OP’s combo fall into that narrow range.
The results on his dyno sheet have that parameter pretty far outside what I would consider the “normal” range........ without there being any reason(in my mind) why it would be that much better.
AndyF’s 572 example, along with Jeff’s 563....... also fall right into what I consider the normal range.
That parameter? TQ/CI
Bob’s 529 is showing 1.465/ci........ which on the dyno here is extremely rare for a single carb on gas. The normal range for typical bracket race builds? Well, here they are normally in the 1.30-1.35 range.
I see nothing in Bob’s build that would indicate it would fall outside that window.
So, this also falls into the “racing dynos” theme, which is why I stipulated that the numbers would look quite a bit different if the engine were tested here, with my dyno headers......... in the same way all the other “better” combos belted out 1.30-1.35 TQ/CI. Perhaps seeing 1.45+ TQ/CI isn’t that odd of an occurrence where Bob tested. But no single carb BBM has ever really gotten close to that on the dyno here.
If the TQ/CI number for Bobs 529 ended up at 1.35 here, the peak TQ number would be about 715 instead of in the 770’s.
Looking thru a pile of old dyno sheets, I only see one single carb BBM build that exceeded 1.35, which is a 14:1 572 with 4401-345’s on it...... and that one went 1.37. There are also quite a few sheets from pretty nice running combos, making what I feel is decent power....... that didn’t quite make it to 1.30. OK yes but the peaks and there corresponding RPM to me makes me consider the cam is not what it was advertised. And the headers being so small they could compound that to help explain the RPM AND the unusually high torq value as well.
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Re: dyno time
[Re: HardcoreB]
#3130082
03/17/23 10:23 AM
03/17/23 10:23 AM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
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Sean, in my mind it’s a dyno/facility thing in this case.
I’ve had my own motor show over a 60hp spread between two different dynos, along with quite a few other engines I’ve tested, that had been tested somewhere else, where the sheets looked different enough you wouldn’t even guess it’s the same engine.
What I’m saying is, in my 33 years of dyno testing....... I’ve seen drastically different numbers, gleaned from different dynos, often enough to acknowledge it’s a real thing.
I still say the right course of action for Bob is to just put the motor back in the car and let the timeslip be the judge of whether the motor picked up with the new cam. It’s just a new cam, not a new “combo”.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: dyno time
[Re: fast68plymouth]
#3130090
03/17/23 10:36 AM
03/17/23 10:36 AM
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HardcoreB
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Sean, in my mind it’s a dyno/facility thing in this case.
I’ve had my own motor show over a 60hp spread between two different dynos, along with quite a few other engines I’ve tested, that had been tested somewhere else, where the sheets looked different enough you wouldn’t even guess it’s the same engine.
What I’m saying is, in my 33 years of dyno testing....... I’ve seen drastically different numbers, gleaned from different dynos, often enough to acknowledge it’s a real thing.
I still say the right course of action for Bob is to just put the motor back in the car and let the timeslip be the judge of whether the motor picked up with the new cam. It’s just a new cam, not a new “combo”. Yes ok and thank you. I just am having a rough time getting around the RPM issues.
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Re: dyno time
[Re: fast68plymouth]
#3130093
03/17/23 10:42 AM
03/17/23 10:42 AM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
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Here’s another thought I had in mulling the results over........ On this combo.......13:1 529” bracket race build....... is the best cam installed position going to be the same if you’re testing with 1-3/4 to 1-7/8 x 3.5 headers vs 2-1/8 x 4 headers?
Fortunately the engine has a jesel belt on it so moving the cam is pretty easy.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: dyno time
[Re: HardcoreB]
#3130095
03/17/23 10:45 AM
03/17/23 10:45 AM
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Joined: Jan 2003
Posts: 14,496 So. Burlington, Vt.
fast68plymouth
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I have to say in a side note after talking to Bob some time ago on the phone he is a pleasant/likeable guy and I hope this iteration refresh gets him to his goal...Good luck Bob! Indeed! One of the nicest people you’ll ever meet.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: dyno time
[Re: AndyF]
#3130169
03/17/23 03:15 PM
03/17/23 03:15 PM
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Joined: Feb 2008
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sr4440
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Let me add my 2 cents, using a 1 7/8 header on a 529 that you plan on using 2 1/8 exhaust on, gave you a lot of useless info. The HP/TQ will be down, the A/f will be off, the timing won’t be right. The good news is the oil pressure, the vacuum shouldn’t change, and you got to see if it leaked. I ran a 512 with that same cam and when I shorten the 2 1/8 headers from a 32” primary to a 28, I pick up 18hp. My advice is put the cam back at 108, put it in the car and go have some fun.
Joe
Last edited by sr4440; 03/17/23 03:17 PM.
Without Data, you’re just another guy with an opinion.
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Re: dyno time
[Re: GomangoCuda]
#3130176
03/17/23 03:47 PM
03/17/23 03:47 PM
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Joined: Jan 2003
Posts: 31,027 Oregon
AndyF
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Andyf: does that oil pan have a big window in the side? Yes. That engine had windows everywhere. Valve covers, valley plate, oil pan, etc. That was a dyno mule that we used to test parts.
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