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Re: Holley 750 vs 850 vs 950 [Re: skrews] #2530949
08/03/18 01:30 PM
08/03/18 01:30 PM
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Posts: 19,317
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Thumperdart Offline
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Originally Posted By skrews
Originally Posted By BradH
Originally Posted By skrews
Probably just going to run the 1.45 carb as I probably won't get a lot of hits, and I'm trying to iron out its unstable fuel curve. Modified a set of scrap metering blocks thinking it might actually want more emulsion not less. We shall see LOL.

I'm interested in hearing how you've set up the carb, and what you're seeing w/ the fuel curve issues you mentioned. work


I made a few shake down runs at the local 1/8 mile track and the wide band skipped around by 3/4 of a point or so. My 1.375/1.68 carb was very steady,and the 1.375/1.75 carb was pretty behaved too. All these carbs have 3310 primary blocks with 2 .027 e holes and 26 to 28 HSAB. Despite the 1.45 carb's erratic fuel curve, it still managed to tie the best ET and generate the best MPH at the local 1/8 track in worse air. I added a third .027 e hole to a set of scrap 3310 blocks, and will also try bumping up to the supplied .032 HSAB and see what happens at the 1/4 mile track Friday.


I love this stuff and you SHOULD see it dip rich down low a tad then trend lean up top with the .032 hi bleeds............I say SHOULD......... biggrin Lookin forward to your results.........


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.....
Re: Holley 750 vs 850 vs 950 [Re: Thumperdart] #2530957
08/03/18 01:38 PM
08/03/18 01:38 PM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline
Taking time off to work on my car
BradH  Offline
Taking time off to work on my car
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Val-haul-ass... eventually
Originally Posted By Thumperdart
biggrin Lookin forward to your results.........

Same here. I'm having to do all my carb learnin' vicariously until my own junk is running again.

Re: Holley 750 vs 850 vs 950 [Re: skrews] #2530969
08/03/18 02:03 PM
08/03/18 02:03 PM
Joined: Jan 2003
Posts: 2,094
central texas
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krautrock Offline
top fuel
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top fuel
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central texas
Originally Posted By skrews
Originally Posted By BradH
Originally Posted By skrews
Probably just going to run the 1.45 carb as I probably won't get a lot of hits, and I'm trying to iron out its unstable fuel curve. Modified a set of scrap metering blocks thinking it might actually want more emulsion not less. We shall see LOL.

I'm interested in hearing how you've set up the carb, and what you're seeing w/ the fuel curve issues you mentioned. work


I made a few shake down runs at the local 1/8 mile track and the wide band skipped around by 3/4 of a point or so. My 1.375/1.68 carb was very steady,and the 1.375/1.75 carb was pretty behaved too. All these carbs have 3310 primary blocks with 2 .027 e holes and 26 to 28 HSAB. Despite the 1.45 carb's erratic fuel curve, it still managed to tie the best ET and generate the best MPH at the local 1/8 track in worse air. I added a third .027 e hole to a set of scrap 3310 blocks, and will also try bumping up to the supplied .032 HSAB and see what happens at the 1/4 mile track Friday.


what jetting were you running the 1.45 carb?

Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531100
08/03/18 06:13 PM
08/03/18 06:13 PM
Joined: Jan 2003
Posts: 14,479
So. Burlington, Vt.
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fast68plymouth Offline
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My HP950 that I built from scratch over 15 years ago uses a genuine Holley HP950 body, 1.375x1.750 configuration.
I installed Braswell stepped boosters with .160 feed holes and lightly blended the Venturi.
When I first put it together I used some billet metering blocks from BLP.
We discussed what size the main wells and angle channels would be, but I don’t recall what those dimensions are.
I tested it on a few motors on the dyno and it was really rich everywhere unless unusually small jets were used along with big hsab’s.
The problem with that was, the throttle response was on the poor side.
I swapped to some stock 3 emulsion HP metering blocks which helped some(smaller main well and angle channel), but had to keep going up with the hsab to try and reduce its tendency to richen up at the top end of the curve, while allowing for big enough main jets to help with the response.

It still doesn’t have “awesome” response, and still tends to slightly richen up in the upper rpms, but all in all it runs well enough to be used as a decent dyno carb.
Jets are 74pv/83, hsab is .040.

What it really needs is a booster change to something with a smaller feed hole, which would allow for bigger jets and smaller hsab. I have the boosters....... and someday I’ll probably get around to swapping them out.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Holley 750 vs 850 vs 950 [Re: fast68plymouth] #2531108
08/03/18 06:39 PM
08/03/18 06:39 PM
Joined: Jan 2003
Posts: 30,947
Oregon
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AndyF Offline
I Win
AndyF  Offline
I Win
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Posts: 30,947
Oregon
When you have a couple of weeks where you won't be using the carb just send it to Mark W. and ask him to change the boosters for you and to flow it on his bench. He'll take care of it so you can keep making money doing what you do.

Re: Holley 750 vs 850 vs 950 [Re: Thumperdart] #2531387
08/04/18 07:07 AM
08/04/18 07:07 AM
Joined: Jul 2012
Posts: 425
Washington
skrews Offline OP
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Washington
Originally Posted By Thumperdart
Originally Posted By skrews
Originally Posted By BradH
Originally Posted By skrews
Probably just going to run the 1.45 carb as I probably won't get a lot of hits, and I'm trying to iron out its unstable fuel curve. Modified a set of scrap metering blocks thinking it might actually want more emulsion not less. We shall see LOL.

I'm interested in hearing how you've set up the carb, and what you're seeing w/ the fuel curve issues you mentioned. work


I made a few shake down runs at the local 1/8 mile track and the wide band skipped around by 3/4 of a point or so. My 1.375/1.68 carb was very steady,and the 1.375/1.75 carb was pretty behaved too. All these carbs have 3310 primary blocks with 2 .027 e holes and 26 to 28 HSAB. Despite the 1.45 carb's erratic fuel curve, it still managed to tie the best ET and generate the best MPH at the local 1/8 track in worse air. I added a third .027 e hole to a set of scrap 3310 blocks, and will also try bumping up to the supplied .032 HSAB and see what happens at the 1/4 mile track Friday.


I love this stuff and you SHOULD see it dip rich down low a tad then trend lean up top with the .032 hi bleeds............I say SHOULD......... biggrin Lookin forward to your results.........

Made to the track. Wind was blowing pretty good so the powers that be decided to run 1/8 mile. LAME. Anyway I tried the 1.45 carb with the .032 HSAB for the first few runs, then swithed out for .027 on my last pass. The AFR was rock solid stable with the .032 and varied about half a point with the .027. MPH fell off a few hundredths with the .027. This was with the untouched 3310 metering blocks. Main jets are 78/86, AFR was 12.9-13.0. Didn't seem to run rich at the bottom of the gears with the .032 HSAB. All in all I'd say if the car picked up anything it wasn't enough to notice, but a fun tuning/learning experience none the less. More flogging is necessary sawzall

Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531428
08/04/18 11:55 AM
08/04/18 11:55 AM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
master
polyspheric  Offline
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New York
Watch the facial expression of a carb tuner when some 2-stroke person says "why would you want the A:F ratio to remain constant throughout the RPM range, and in every gear?"


Boffin Emeritus
Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531479
08/04/18 01:42 PM
08/04/18 01:42 PM
Joined: Jul 2004
Posts: 19,317
State of confusion
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Thumperdart Offline
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I've seen my car go just slightly rich at the hit and down low with the bigger hi bleed then a nice transition to a leaner mid and top end. Good info either way and how we keep learning............. thumbs


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.....
Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531481
08/04/18 01:43 PM
08/04/18 01:43 PM
Joined: Jul 2004
Posts: 19,317
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Thumperdart Offline
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Originally Posted By skrews
Originally Posted By Mark Whitener
Originally Posted By skrews
Flow tested a few carbs the other day, thought I'd share my findings. The Ultra HP carbs are the older design from around 2005 they are no longer sold.

Holley Ultra HP 750 part#80675
1.375 venturi / 1.687 base plate
819 cfm

Holley Ultra HP 950 part#80676
1.375 venturi / 1.75 base plate
825 cfm

Holley 850 "old style main body" part# 9380
Choke horn milled off, slabbed throttle shafts, annular boosters
1.58 venturi / 1.75 base plate
945 cfm

I'll be replacing the 1.375 main body of the 950 with a 1.45 main body and retesting in the coming weeks.

This test backed my suspicions about the true flow of the 950, as it was only able to make about 5 more HP than the 750 on an upper 500 HP 360 motor. 950 my ass lol, I know Holley took a lot of [censored] over that carb and the new XP950 has a 1.6 venturi because of it.


Be aware that that new 950 with the 1.60 venturi is a poor choice. The entrance shape causes turbulence. I've had 3 on my flow bench, put every booster available in it. Flow and booster signal are down because of it, and I can get a 1.45 venturi Quick fuel to flow the same and have a much better booster signal. And you can hear the turbulence on the bench. Quick Fuel/Proform bodies are a much better choice, the entrance to the venturi is shaped better, as well as the new billet bodies from BLP and APD.


I've heard that about the 950 XP. That's why I'm working with the 1.45 QFT main body. Should be a good match to my engine.


If I missed it, what motor are you testing these on......... thumbs


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.....
Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531500
08/04/18 02:41 PM
08/04/18 02:41 PM
Joined: Jul 2012
Posts: 425
Washington
skrews Offline OP
mopar
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Washington
[/quote]
If I missed it, what motor are you testing these on......... thumbs [/quote]

360
11.75 comp
596 heads 2.02/1.6 flow 265/180
worked over M1 single plane
2" tapered spacer
1.75 Super Comp headers
.528/.528 252°/252° @.050 108+5 SFT
Duster 3350#, 904 5800ish converter, 4.56, 28x10.5

Here is the intake about half way done

Last edited by skrews; 08/04/18 02:42 PM.
Re: Holley 750 vs 850 vs 950 [Re: skrews] #2531648
08/04/18 10:03 PM
08/04/18 10:03 PM
Joined: Jul 2004
Posts: 19,317
State of confusion
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Thumperdart Offline
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Originally Posted By skrews
[/quote]
If I missed it, what motor are you testing these on......... thumbs


360
11.75 comp
596 heads 2.02/1.6 flow 265/180
worked over M1 single plane
2" tapered spacer
1.75 Super Comp headers
.528/.528 252°/252° @.050 108+5 SFT
Duster 3350#, 904 5800ish converter, 4.56, 28x10.5

Here is the intake about half way done
[/quote]

Good combo, thumbs and fwiw, 18+ years ago, I ran an 850 speed demon which flowed 920 cfm on my daily driver stock stroke 360 w/stock heads, a solid Isky cam and a Pettis valve job at about 11.5 iirc and went a best of 11.88 @114 mph at LACR's altitude track. I mixed race gas but the point is that motor like most responded to more cfm and went from mid 12's to my 11.88 so I like to over carb apparently but it seems to work MOST of the time but not always........... beer


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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