treyrags wrote: ↑Sat Mar 16, 2024 6:59 am
Something to check on the Progression misfire if you haven't already. The switched power to the distributor must be a full 12V. When I first ran mine it had a very slight misfire at higher rpm. My switched power was below 12V. I changed the wiring to correct it. The miss went away and has run flawless since. I do not use my ignition box, just an E-core type coil. Have run it to 7200 many times with no problem.
The last thing I will be doing before coming off the dyno is to put the Progression Ignition distributor back in to check it is still fine and not damaged by the accidental miss-wiring. The dyno is set up with a relay for 12v ignition supply but I will confirm that is what it is receiving.
What comp ratio is yours engine?
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
treyrags wrote: ↑Sat Mar 16, 2024 6:59 am
Something to check on the Progression misfire if you haven't already. The switched power to the distributor must be a full 12V. When I first ran mine it had a very slight misfire at higher rpm. My switched power was below 12V. I changed the wiring to correct it. The miss went away and has run flawless since. I do not use my ignition box, just an E-core type coil. Have run it to 7200 many times with no problem.
The last thing I will be doing before coming off the dyno is to put the Progression Ignition distributor back in to check it is still fine and not damaged by the accidental miss-wiring. The dyno is set up with a relay for 12v ignition supply but I will confirm that is what it is receiving.
treyrags wrote: ↑Sat Mar 16, 2024 6:59 am
Something to check on the Progression misfire if you haven't already. The switched power to the distributor must be a full 12V. When I first ran mine it had a very slight misfire at higher rpm. My switched power was below 12V. I changed the wiring to correct it. The miss went away and has run flawless since. I do not use my ignition box, just an E-core type coil. Have run it to 7200 many times with no problem.
The last thing I will be doing before coming off the dyno is to put the Progression Ignition distributor back in to check it is still fine and not damaged by the accidental miss-wiring. The dyno is set up with a relay for 12v ignition supply but I will confirm that is what it is receiving.
What comp ratio is yours engine?
10.9
We were thinking it was the engines high comp (static 11.57:1) that it was having trouble with jumping the gap as there was an improvement closing the gap .010”. But giving it more thought it’s an unknown if the blue MSD HVC was on its way out or not. So I will definitely try it again with a different coil and confirming 12v to coil. It won’t go to waste as the old 383 will be revived.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Did a few more runs today. This time focusing on the two annular carbs. An 850cfm Mighty Demon annular (1.56" venturi x 1.75" throttle bore) and the 1050cfm silver sleeve Race Demon (1.59" venturi x 1.75" throttle bore) Neither could repeat the 538ft/lb or 571hp of the 975cfm downleg (1.500" x 1.75" throttle bore). Best we seen with either annular was 531ft/lb @ 4950rpm. Today only pulled as high as 6000rpm. The dyno was having a random power supply issue and had to abandon a couple of runs, so stayed at 6000rpm. Highest observed with the 1050cfm was 563hp @ 6000rpm. Seems to be pointing to what we all know, that the heads are the biggest restriction in the system.
Tomorrow the new ICE coil will be fitted and then the 825cfm will get a crack at it. The 825cfm Race Demon RR has been set to factory specs so it will be interesting how it performs, especially afr curve wise. The random power issue should be sorted tomorrow as the owner is getting a tech in. After the 825cfm has had a run or two then 2" of spacer to see if that helps with each carb.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Some screenshots of dyno runs. The afr for the 850 and 975cfm trends from richest on the even cylinder bank (LB-1) to evening up between banks (LB-1/LB-2) around peak tq to then swapping to richer on the odd bank (LB-2) side. The 1050cfm still has the same effect but at higher rpm.
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I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Tom68 wrote: ↑Mon Mar 18, 2024 5:36 am
I wonder what's with the 1050 having the highest manifold Vac, implies it's the most restrictive.
Something isn't right with the sensor. I'm not taking it at face value. The highest flowing showing the highest restriction and lowest cfm least restriction. Hopefully the tech will fix that too.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Tom68 wrote: ↑Mon Mar 18, 2024 5:36 am
I wonder what's with the 1050 having the highest manifold Vac, implies it's the most restrictive.
Something isn't right with the sensor. I'm not taking it at face value. The highest flowing showing the highest restriction and lowest cfm least restriction. Hopefully the tech will fix that too.
Same with the IAT thermocouple? Seems a tad warm...
Tom68 wrote: ↑Mon Mar 18, 2024 5:36 am
I wonder what's with the 1050 having the highest manifold Vac, implies it's the most restrictive.
Something isn't right with the sensor. I'm not taking it at face value. The highest flowing showing the highest restriction and lowest cfm least restriction. Hopefully the tech will fix that too.
Same with the IAT thermocouple? Seems a tad warm...
I asked about that. Not connected to manifold.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
rgalajda wrote: ↑Tue Mar 19, 2024 2:48 am
I'm wondering how accurate the hp/torque readings are.
Time and the track will tell. The dyno sessions have served their purpose. I won't lose any sleep if the real hp and tq numbers are 10 - 15 less than the results show as that's all I expected anyway.
I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
Gave the 825 Race Demon RR a run today. It was set up as per factory specs. It showed again the heads are the cork. Performed very well. This carb has pv front and rear, the much maligned .031" x .031" x .031" emulsion and .038" mab. Jets were 76 front & rear. Proved to be a bit lean up top so dropped down to .031" mab. Closer but enriched it with 78 F&R jets. It made 534ft/lb @ 4850 to 4950rpm and 564hp @ 6500rpm (was a 6500rpm pull). It made 563hp from 6100rpm to 6450rpm.
Put a 1" open spacer under the 1" combo spacer we had been using to date.Peak tq was now 532ft/lb @ 5400rpm and peak power 569hp from 6200rpm to 6300rpm.
Ran the 975cfm again and this time peak 568hp @ 6500rpm and 532ft/lb @ 4900rpm. I'm attributing the reduction in hp/tq today due to having a 5-10min break between test whereas the 571hp run from the other day the engine wasn't turned off for several runs. We just ducked in and out of the cell to change total timing on the ICE box. Temp was kept in the oil.
The 975cfm showed similar trend with the extra 1" of spacer. Raised peak tq to 5250 - 5350rpm where it made 530ft/lb and power output 567hp from 6200 to 6350rpm.
Some testing of the vacuum advance feature on the ICE box tomorrow and re-fit and check the Progression distributor is working and then all done.
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I’m a Street/Strip guy..... like to think outside the quadrilateral parallelogram.
rgalajda wrote: ↑Tue Mar 19, 2024 2:48 am
I'm wondering how accurate the hp/torque readings are.
Time and the track will tell. The dyno sessions have served their purpose. I won't lose any sleep if the real hp and tq numbers are 10 - 15 less than the results show as that's all I expected anyway.
What do you feel, if any, will be the losses once it's in the car? Headers and exhaust will most likely take something out of the dyno numbers. And accessory drives: P/S, alternator, water pump, etc.
