Re: All the specs to start your dyno #s guesses! 8^)
[Re: krautrock]
#2391895
10/23/17 04:41 PM
10/23/17 04:41 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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Taking time off to work on my car
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Went back to look at the list of carbs.
Did 6A make it on the motor? Figure that carb might've had a little calmer emulsion than some of the others. We did run 6A... briefly. It was not a "happy" carb and didn't even make one full pull before we yanked it off and tried a different carb.
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: Thumperdart]
#2391900
10/23/17 04:47 PM
10/23/17 04:47 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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I'm sure that would help with the part throttle. Did you guys mess w/the emulsion cos you can change the mixture quite easily in the range needed buy the location and sizes......... Not enough time to "go deep" on any one carb with multiple items on the test checklist. I'm going to take a s.w.a.g. that a day on the dyno spent on tuning ONE carb is probably enough to get a basic carb sorted out, if the original tune isn't close.
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2391906
10/23/17 04:54 PM
10/23/17 04:54 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
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State of confusion
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Went back to look at the list of carbs.
Did 6A make it on the motor? Figure that carb might've had a little calmer emulsion than some of the others. We did run 6A... briefly. It was not a "happy" carb and didn't even make one full pull before we yanked it off and tried a different carb. That thing had issues for me also but it went into the 12's-13's on my car then I figured you'd sort it out from there but apparently Andy's testing showed it to be good also......... IF you would of spent more time on one as stated, the end results could of been better and ironed out.........good stuff and info guys........
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2391908
10/23/17 04:55 PM
10/23/17 04:55 PM
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Joined: Jan 2003
Posts: 14,513 So. Burlington, Vt.
fast68plymouth
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I'm going to take a s.w.a.g. that a day on the dyno spent on tuning ONE carb is probably enough to get a basic carb sorted out, if the original tune isn't close. And sometimes....... Even after a full day...... You might still not get there if what it really needs from the start is a booster change, and you don't have the pieces on hand to perform that operation.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2391915
10/23/17 05:06 PM
10/23/17 05:06 PM
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Joined: Jan 2003
Posts: 14,513 So. Burlington, Vt.
fast68plymouth
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So. Burlington, Vt.
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Went back to look at the list of carbs.
Did 6A make it on the motor? Figure that carb might've had a little calmer emulsion than some of the others. We did run 6A... briefly. It was not a "happy" carb and didn't even make one full pull before we yanked it off and tried a different carb. In hindsight, we probably should have stuffed the 88/99 jets in it and made a pull with it, just to "get a number".
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: fast68plymouth]
#2391959
10/23/17 06:20 PM
10/23/17 06:20 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
I Live Here
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I Live Here
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State of confusion
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Went back to look at the list of carbs.
Did 6A make it on the motor? Figure that carb might've had a little calmer emulsion than some of the others. We did run 6A... briefly. It was not a "happy" carb and didn't even make one full pull before we yanked it off and tried a different carb. In hindsight, we probably should have stuffed the 88/99 jets in it and made a pull with it, just to "get a number". Agreed although a bit "outta the park" but the old adage of give it what it wants apply's a LOT when testing..........
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: sr4440]
#2391997
10/23/17 07:32 PM
10/23/17 07:32 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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Since this is a street car, were you running a PCV valve? Then tend to lean out the low to mid-range without having much affect up top.
No PCV. Unless I have some type of separator to ensure oil doesn't get sucked back into the induction system, I won't be using one, either. Oil in combustion chamber = Bad JuJu
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2392042
10/23/17 09:38 PM
10/23/17 09:38 PM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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My scoring methodology is to add the differences in estimated HP and torque from the actual results for each category. If there is a tie, then the same approach based upon RPM differences would be the deciding factors.
Winners: - Baseline test - RAMM - Best test - 572B1
FWIW, 572B1 was also 2nd in Baseline, and Triple Threat was 2nd in Best with a score only 1 point behind 572B1!
If you notice Triple Threat copies me and than super tunes
Gen 3 power 6.22@110, 9.85@135 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: fast68plymouth]
#2392045
10/23/17 09:45 PM
10/23/17 09:45 PM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Charleston
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Keep in mind the wot a/f ratios were fairly decent on both the QFT carbs when they made their best runs. So, whatever you do to lean out the part throttle cruise, you're trying to do something that changes that part of the carbs operation by around 3 points......and have essentially zero affect on wot operation.
There are smarter guys with carbs than me, but I have a feeling it's easier said than done.
The QFT 1.52 carb had the least offensive part throttle cruise operation when it was first bolted on.......low/mid-12's, with the 80/90 jets. However, with that set up, the motor didn't take a load real well, and I aborted the run about 800rpm into it when I saw the a/f ratios weren't getting out of the 15's.
Once the jetting was increased to get the wot a/f ratios in line, and the power up......which ended up being 88/98....... then the part throttle cruise was down at the bottom of the 11's.
The Demon had the next best part throttle operation, low-12's, and had the best throttle response. IMO, this carb is probably the best candidate of what we ran to be tweaked to get decent part throttle operation for street use. The down side of this carb as we ran it was, it had the biggest change in wot a/f operation from the bottom of the run to the top........it really richened up at the top end. How about going as big as possible on the pvcr? That is what I always do. But Im an idiot but it seems to work
Gen 3 power 6.22@110, 9.85@135 Follow @g3hemiswap on instagram
performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: sixpackgut]
#2392214
10/24/17 09:32 AM
10/24/17 09:32 AM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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How about going as big as possible on the pvcr? That is what I always do. But Im an idiot but it seems to work
Yeah, that'll be something I expect to try.
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: davenc]
#2392216
10/24/17 09:37 AM
10/24/17 09:37 AM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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... I know you go for every last bit, but are you going to even notice the difference of 10HP on a 700HP motor?!!!
For me, the Demon is the clear winner, and the best choice to spend time fine tuning. 10 HP will definitely show up on the ET slip. For me, there was no clear winner... but IMO one of the carbs tested isn't worth putting much -- maybe any -- effort into.
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2392296
10/24/17 12:46 PM
10/24/17 12:46 PM
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Joined: Jan 2003
Posts: 14,513 So. Burlington, Vt.
fast68plymouth
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I feel if the fuel curve on the Demon could be sorted out, it would have made within a few hp of the others...... As they were. It had the biggest spread in A/F ratio within a pull. Going from memory, it had areas near the bottom where it was in the 14's, and ended up in the 11's at the top.
I'm fairly certain there is 5-10hp left on the table if you could really get one of the annular carb combos dialed right in.
I base that off the last few pulls we made, in which we tried my dyno mule HP950, which was within a couple tq/hp of the others. I have A/B'd that carb quite a few times against my old CFS built annular 850, and the CFS carb is usually worth 5hp+ over the my 950. In all fairness though, while the CFS carb does make good power, it also would not have been any better at part throttle than the QFT carbs. It's pretty rich on the bottom.
The dyno mule HP950 is something I built from a bare Holley body and old style HP metering blocks. I used Braswell stepped boosters in it, and it has a tendency to slightly richen up from bottom to top. Trying this carb on this motor for me was sort of a "control" test, to guage if the characteristic we were seeing of all the carbs richening up was something peculiar to the combo, or just what the carbs were doing. If anything, on Brads motor, I'd say the dyno 950's tendency to richen up was slightly less than what is typical with it.
Also, I've run that carb on many motors and its never shown a problem being lean before, so again..... As a control item...... If it would have required a bunch of jet put in it, it would point the finger at a combo specific issue, not so much a carb issue. The A/F ratio was mid/hi-12's for most of the pull, and richened up to low 12's at the end.....with the std jetting I had in it.
The motor itself didn't appear to present any out of the ordinary challenge for fuel delivery to the carbs...... The ones that required really big jets to get the wot A/F ratios right are just configured in a way where that was the case. My dyno mule 950 was flowing plenty of fuel with only 75/84 jets(primary pv).
The motor was using about 20cfm more air at the top end of the pull with the bigger carbs....... So there is some power to be gained if the metering is really sorted out.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: fast68plymouth]
#2392329
10/24/17 01:54 PM
10/24/17 01:54 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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I feel if the fuel curve on the Demon could be sorted out, it would have made within a few hp of the others... Yeah, something in the current tune w/ the Race Demon (which basically duplicated what my Gold Claw last used on the car) is just... wrong. The previous dyno tests w/ the Gold Claw using a different emulsion config started & ended in a normal A-F range, but had a prominent lean swing in the mid-range. I thought the basic changes I made would have simply flattened out the curve, not make it go progressively richer as the RPM increased. IIRC, (don't have my notes on hand), with both carbs set up w/ 1.42" venturi sleeves, .026 & 70 air bleeds, 80 pri & 90 sec jets, .035 IFRs, and the same .160" ID downleg boosters, the difference was the original Gold Claw emulsion stack was .031"/blank/.031"/blank/.031", whereas I set up the Race Demon with .028"/blank/blank/.028"/blank (more of a traditional Holley DP configuration). Regardless, the two tunes ran waaay differently re air-fuel curves than I would guessed. I'm fairly certain there is 5-10hp left on the table if you could really get one of the annular carb combos dialed right in. That's what I'm hoping, but am in wait-and-see mode until the car's back on the track. One thing I did notice was the run w/ the QF 1.59 annular using the 32 MABs actually made more power across the RPM range, even though it went rich at the very end, than the subsequent runs where we leaned out the MABs. That original QF 1.59 annular pull made more power across most of the RPM range than the QF 1.52 downleg did w/ the 88/98 tune, too. That 1.52 tune is quite a bit richer than I'd expected because the QFT RQ-1000 tune out-of-the-box has 82 & 88 jets and a much leaner .035 MAB. Those BLP .450" ID x .155" leg boosters worked REALLY differently than I anticipated. I thought w/ their improved booster signal that they'd want less jet, not more. FWIW. I checked last night and verified the QFT RQ-1050-AN tune w/ THEIR metering blocks starts at 33 & 73 air bleeds, 84 pri & 90 sec jets, and .035 IFRs. I'm not 100% sure about their emulsion stack -- although I think whatever they don't plug gets .029" or .031" e-jets -- or their PVCRs size. I put mine together using Holley Ultra XP .160" angle channel metering blocks with 32 & 73 bleeds, 84 & 92 jets, .035 IFRs (lowered), an emulsion stack of .0305"/blank/.0305"/blank/blank, and .059" PVCRs. ALL of my carbs have room to mess w/ their tunes.
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Re: All the specs to start your dyno #s guesses! 8^)
[Re: BradH]
#2392911
10/25/17 02:36 PM
10/25/17 02:36 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
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FWIW, I plan in the next couple of days to post a "before" pull from my old combination and an "after" pull from the new one to see where & how much it picked up. Here's one: - Stg VI SFT A = Stage VIs w/ 266 at .050 x .600" on 108 SFT with ported Victor (no spacer, since it wouldn't fit under the old hood) and my Gold Claw carb set up with the 1.42" venturi sleeves - Victor SR A = PRH Victors w/ 266 x .050 x .650" on 108 Solid Roller w/ mildy modified Trick Flow intake, 1" Super Sucker spacer, and the QFT 1.52 v downleg carb I've got the raw #s, but thought the graph presented better. The thing that most stands out -- for me, at least -- is this wasn't simply a gain on the top end. It pretty much gained everywhere across the test RPM range.
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