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Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391395
10/22/17 07:37 PM
10/22/17 07:37 PM
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BradH Offline OP
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QFT 1.52" v with BLP downleg boosters, 38* timing, 1" Super Sucker spacer
- 677.7 at 6800, 603.3 at 5100
- gained power with each additional 2* advance
- too lean with starting 80/90 jets; ended up with 88/98
- part throttle not great

QFT 1.59" v annular, 38* timing, 1" Super Sucker
- 678.0 at 6800, 606.8 at 5100
- going rich above 6700
- part throttle even fatter than the 1.52 downleg

Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391399
10/22/17 07:42 PM
10/22/17 07:42 PM
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BradH Offline OP
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QFT 1.52 downleg, 38*, 2" Super Sucker
- 684.2 at 6800, 606.2 at 5000
- the "Big Number Run" although I would not be able to use a 2" spacer with an air cleaner, even with my raised T/A scoop

tonguue

Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391420
10/22/17 08:27 PM
10/22/17 08:27 PM
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Pattison Texas
CSK Offline
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I am very surprised it liked 38* timing.


1968 Charger COLD A/C Hilborn EFI
512ci 9.7 compression, Stealth heads, 4.10 gear A518 ODtrans 4100lb,10.93 full street car trim
2020 T/A 392 Stock 11.79 @ 114.5

Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391423
10/22/17 08:36 PM
10/22/17 08:36 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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We ended up putting 5 different carbs on the motor, and all were briefly tested for part throttle operation.
At a variety of low loads(35-80-ish hp), at a variety of rpm's(2200-3200), looking at A/F ratios being displayed from the flow turbines and a Daytona Sensors wide band showed that none of the 5 had what either of us considered "acceptable" part throttle operation...... with the best of them being in the low-12's, and some in the 11.0-11.2 range.
They worked perfectly well to use on a "race car", but wouldn't be the hot ticket on the street(in their current configuration).

I can't believe I'm going to say this........but........this is an example of a good argument for EFI.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: All the specs to start your dyno #s guesses! 8^) [Re: Clanton] #2391430
10/22/17 08:49 PM
10/22/17 08:49 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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Originally Posted By Clanton
Can you post a couple tq# from 3k rpm?THX!


The pulls were started at 3500.

Once we started to get it dialed in, the tq at 3500 was a little over 500.

Things didn't really start to happen until it was closer to 4K.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391438
10/22/17 09:03 PM
10/22/17 09:03 PM
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northern,Ohio,USA
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Thank you for all of your results!


GOTBOOST!New improved with Victor heads.
http://www.enginelabs.com/mopar-big-bloc...t-of-necessity/
Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391444
10/22/17 09:11 PM
10/22/17 09:11 PM
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The Great White North
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You did better than I thought on HP but I was fairly close on my TQ guess. IFR and PVCR circuits are always too big it seems for part throttle operation. Good job Brad and Dwayne and thankyou for sharing this. Brad your big block is going to feel like a supersized small block with this power and RPM. J.Rob


2009 PHR\EMC Competitor
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Re: All the specs to start your dyno #s guesses! 8^) [Re: CSK] #2391454
10/22/17 09:42 PM
10/22/17 09:42 PM
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Sydney,Australia
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Originally Posted By csk
I am very surprised it liked 38* timing.

my 440 liked the same 38/39. my 505 is 35 iirc
a function of efficiency
Well done Brad and Dwayne , good to see the results

Tex

Last edited by tex013; 10/22/17 09:43 PM.

New best ET 10.259@129.65 .
New best MPH 130.32
Finally fitted a solid cam,
stepped it up a bit more
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New World block 3780lbs 10.278@130.80 . Wowser 10.253@130.24 footbraking from 1500rpm
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Re: All the specs to start your dyno #s guesses! 8^) [Re: fast68plymouth] #2391480
10/22/17 10:22 PM
10/22/17 10:22 PM
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Oregon
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AndyF Offline
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Originally Posted By fast68plymouth
We ended up putting 5 different carbs on the motor, and all were briefly tested for part throttle operation.
At a variety of low loads(35-80-ish hp), at a variety of rpm's(2200-3200), looking at A/F ratios being displayed from the flow turbines and a Daytona Sensors wide band showed that none of the 5 had what either of us considered "acceptable" part throttle operation...... with the best of them being in the low-12's, and some in the 11.0-11.2 range.
They worked perfectly well to use on a "race car", but wouldn't be the hot ticket on the street(in their current configuration).

I can't believe I'm going to say this........but........this is an example of a good argument for EFI.


Yep, Holley carbs are almost always rich in the mid-range. On the dyno you can crutch it by turning the idle screws in since you don't usually need the idle circuit on the dyno. On a street car it needs to be sorted out. On the dyno we typically use the idle screws to get the mid-range cleaned up and then use the main jets for WOT. It takes way too much time to mess with the PVCRs during testing. Besides, it all changes once the engine goes in the car so no reason to mess with the carb twice.

And I agree with your EFI comment. Once you start tuning EFI engines you'll wonder why people waste their time with carbs!

Last edited by AndyF; 10/22/17 10:23 PM.
Re: All the specs to start your dyno #s guesses! 8^) [Re: fast68plymouth] #2391484
10/22/17 10:25 PM
10/22/17 10:25 PM
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Charlotte, North Carolina
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Originally Posted By fast68plymouth

At a variety of low loads(35-80-ish hp), at a variety of rpm's(2200-3200), looking at A/F ratios being displayed from the flow turbines and a Daytona Sensors wide band showed that none of the 5 had what either of us considered "acceptable" part throttle operation...... with the best of them being in the low-12's, and some in the 11.0-11.2 range.
They worked perfectly well to use on a "race car", but wouldn't be the hot ticket on the street(in their current configuration).

I can't believe I'm going to say this........but........this is an example of a good argument for EFI.


Why do you say that? Just because nobody had time to fix a part throttle lean issue? An EFI system with a lean part throttle concern is still going to need calibration also. 5 minutes booting up a laptop or 5 minutes changing a bleed. I had someone drive over their laptop on a test day. Guess how much data we got that day?

Re: All the specs to start your dyno #s guesses! 8^) [Re: tex013] #2391489
10/22/17 10:31 PM
10/22/17 10:31 PM
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BradH Offline OP
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Still about 2 hours out from home & Mike's driving again.

Miscellaneous comments...

I wasn't expecting it to want that much ignition advance. My Stage VIs' sweet spot was 35, which is why we started out about there. But we weren't seeing the results until bumping it up; 36 was better than 34, but 38 was better yet.

The Race Demon fuel curve made no sense given what I'd seen before. We went from .026 MABs to .028, but it wasn't much change. At that point we yanked it off and started testing other carbs.

Things that ended up NOT like I'd expected:
- More torque by about 20 #s... and the peak RPM wasn't really any different than where it was for the old combination

- Harder to get "big" HP numbers, and I'd been HOPING we might be closer to 700, although Dwayne & I agreed it "should" make 670+ before it was tested

- Peak HP RPM... thought it would be around 6500... didn't think the small CSA heads and moderate cam would keep pulling that high

- NONE of the carbs were really "right", even after some tweaking

- The 1.52 downleg needed WAY more jet than I thought it should; we also appear to have maxed out fuel flow capacity of the metering blocks used, since adding more secondary jet stopped much in secondary fuel flow increases before we got to the 98s

- Enough of the carb stuff I saw didn't make sense to me that I ended up stealing Quick Fuel's tune (as much as I knew, at least) for the 1.59 v annular rather than use what I'd intended

Re: All the specs to start your dyno #s guesses! 8^) [Re: sgcuda] #2391496
10/22/17 10:39 PM
10/22/17 10:39 PM
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BradH Offline OP
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Originally Posted By sgcuda
Originally Posted By fast68plymouth

At a variety of low loads(35-80-ish hp), at a variety of rpm's(2200-3200), looking at A/F ratios being displayed from the flow turbines and a Daytona Sensors wide band showed that none of the 5 had what either of us considered "acceptable" part throttle operation...... with the best of them being in the low-12's, and some in the 11.0-11.2 range.
They worked perfectly well to use on a "race car", but wouldn't be the hot ticket on the street(in their current configuration).

I can't believe I'm going to say this........but........this is an example of a good argument for EFI.


Why do you say that? Just because nobody had time to fix a part throttle lean issue? An EFI system with a lean part throttle concern is still going to need calibration also. 5 minutes booting up a laptop or 5 minutes changing a bleed. I had someone drive over their laptop on a test day. Guess how much data we got that day?

The part-throttle was rich on all of them, not lean, and really out of normal range in at least one case.

It was a loooong day. Met Dwayne a the dyno at 8:00 AM, last pull was close to 7:30 PM. Then time to break it all down, etc.

Re: All the specs to start your dyno #s guesses! 8^) [Re: RAMM] #2391503
10/22/17 10:45 PM
10/22/17 10:45 PM
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BradH Offline OP
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Originally Posted By RAMM
You did better than I thought on HP but I was fairly close on my TQ guess. IFR and PVCR circuits are always too big it seems for part throttle operation. Good job Brad and Dwayne and thankyou for sharing this. Brad your big block is going to feel like a supersized small block with this power and RPM. J.Rob

Thanks. grin

Funny you mention the small block thing. Since I seem to be one of the few BB people who still run a stock stroke, I've been thinking of my engine as more of a stroker SB... with a really heavy bob weight. wink

Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391509
10/22/17 10:53 PM
10/22/17 10:53 PM
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Charleston
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What did i win?


Stopping in Hazleton for some Senapes Pitza would have been a nice prize

Last edited by sixpackgut; 10/22/17 10:57 PM.

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Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391516
10/22/17 11:01 PM
10/22/17 11:01 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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Quote:
The part-throttle was rich on all of them, not lean, and really out of normal range in at least one case.


And not just a little rich either........some were way way rich with light loads simulating highway driving.
Under those conditions, the main circuit is already flowing plenty of fuel,........and you're not going to lean out the mixture by 3.5 points by tweaking an air bleed.

All the carbs had a tendency to richen up throughout the run(both the turbines and O2 agreed).......some worse than others.

Quote:
- Enough of the carb stuff I saw didn't make sense to me that I ended up stealing Quick Fuel's tune (as much as I knew, at least) for the 1.59 v annular rather than use what I'd intended


And, as I recall, it seemed to have the flattest fuel curve.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: All the specs to start your dyno #s guesses! 8^) [Re: sixpackgut] #2391517
10/22/17 11:01 PM
10/22/17 11:01 PM
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BradH Offline OP
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Originally Posted By sixpackgut
What did i win?

haha

I haven't done the reviews of all the predictions to see who is closest to the two categories... but yours looked pretty good when you first posted them.

I'm still typing this stuff on my phone while on the drive home. I'll try to figure out who gets the Summit gift card(s) as soon as possible, but it may not be until tomorrow.

Re: All the specs to start your dyno #s guesses! 8^) [Re: fast68plymouth] #2391520
10/22/17 11:08 PM
10/22/17 11:08 PM
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central texas
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Originally Posted By fast68plymouth
Quote:
The part-throttle was rich on all of them, not lean, and really out of normal range in at least one case.


And not just a little rich either........some were way way rich with light loads simulating highway driving.
Under those conditions, the main circuit is already flowing plenty of fuel,........and you're not going to lean out the mixture by 3.5 points by tweaking an air bleed.

All the carbs had a tendency to richen up throughout the run(both the turbines and O2 agreed).......some worse than others.


this might be why some of the carb tuners talk about all the newer bodies such as QFT and the variants need transfer slot restrictors in the bodies?

Re: All the specs to start your dyno #s guesses! 8^) [Re: BradH] #2391521
10/22/17 11:10 PM
10/22/17 11:10 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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I'm sure that would help with the part throttle.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: All the specs to start your dyno #s guesses! 8^) [Re: krautrock] #2391523
10/22/17 11:13 PM
10/22/17 11:13 PM
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BradH Offline OP
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Transfer slot restrictions alone won't correct this type of driveability issue, although they may be one the things changed as part of the fix.

Re: All the specs to start your dyno #s guesses! 8^) [Re: fast68plymouth] #2391524
10/22/17 11:15 PM
10/22/17 11:15 PM
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BradH Offline OP
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Originally Posted By fast68plymouth
I'm sure that would help with the part throttle.

Dude! Still about 30 minutes from home... at least we're in the right state now.

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