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Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2741587
02/10/20 03:14 PM
02/10/20 03:14 PM
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Thumperdart Offline
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What are your manifold vacuum readings looking like especially at wide open through the traps........


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: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2741591
02/10/20 03:19 PM
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BradH Offline OP
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The siphon break is another variable in the tuning parameters, from my perspective. And I'm pretty sure you're familiar that tuning for track-only is different than street/strip. Sounds like you're getting valuable data, too, so I'll be interested in hearing what you find improves the tune.

My experience w/ annular boosters coming on too quickly on a dual-purpose application was how it made the car run like a pig at part-throttle. Wasn't an issue at the track, but it also didn't run any quicker or faster than a different carb that ran much cleaner on the street.

Re: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2741593
02/10/20 03:25 PM
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BradH Offline OP
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Originally Posted by Thumperdart
First I've heard of these guys honestly..........

PMRD?

Looks like Mike Laws has partnered w/ them to manufacture & sell the Twin Blade components separately. Wonder if this means he's left Trevor at GG?

Regardless, that's all I've figured out, courtesy of Rusty's post(s) above.

Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2741594
02/10/20 03:26 PM
02/10/20 03:26 PM
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I've changed a bunch of my carbs form 50 CC pumps to 30 CC pumps to help get my cars to 60 ft. better, same thing on squirter sizes(.029 to .033), bigger is not better, unlike on most Chevy motors work shruggy


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Pro Systems King Cobra 4150 carbs [Re: Cab_Burge] #2741754
02/10/20 10:10 PM
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BradH Offline OP
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Pump cam profiles can vary significantly, too. There are some graphs people have posted which show not only how the different cams change the volume of the pump shot, but also where in the arc of the throttle mechanism the cams achieve peak lift. Even though most carbs come with the same cams for primary & secondary pumps, I believe it's more likely that they'll work best with different cams on each side.

Re: Pro Systems King Cobra 4150 carbs [Re: BradH] #2741807
02/11/20 01:39 AM
02/11/20 01:39 AM
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A little late here but maybe I can clear a few things. First the spray bar is nothing new, and we all know the inconsistent nature in a one barrel design. The four barrel should be better, but I'm not sure what they want to accomplish with spray bars that an annular booster won't do better. As far as airflow you can get over 1150 CFM dry with a large 4150 and annular boosters. If you need more the 1200 twin blade is a great option with a 4150 footprint. I will agree they are a little more sensitive to tune in a street car, but not impossible. And on an 800+ HP BBC they make within 5 HP of a 1050 Dominator. The 1400 and 1600 versions are even bigger, but require a lot of manifold work to use on a 4150 manifold. On my SB2.2 the 1600 has been the fastest carb I've run, and I have run up to a 2.800 throttle blade carb that was only .04 slower. On big blocks in the 1000-1200 HP range the 1600 is tough to beat, in the end manifold design has a lot to do with what works best and what the engine needs for distribution.

As far as who came up with the design, there is more to the story. From the 70's, and I've had one in my hand...

[img]https://imgur.com/icOGYmG[/img]
[img]https://imgur.com/S4gA1Jo[/img]
[img]https://imgur.com/9hzzyRc[/img]


Mark Whitener
[url=www.racingfuelsystems.com[/url]
Re: Pro Systems King Cobra 4150 carbs [Re: Mark Whitener] #2741868
02/11/20 10:23 AM
02/11/20 10:23 AM
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Thanks Mark.
I read the posts on your site through "tap a talk" ( may not have written that correctly ) and, as you said here and i read in threads there- manifold design was a big deal and, we saw the results Andy got with the Wilson manifold work.

So, this car being bound to a 4150 flange and, needing more cfm , i called Wilson and we sent them a main body, the heads and manifold.
Results: we gained over 30 hp and the tuning window improved a great deal, manifold vacuum was more consistent through the run as well ( still not sure why on that unless its that reversion pulses are better?
Your thoughts on that would be helpful.
Afr graphs were much, much smoother and, fwiw, our left to right bank jetting stagger is only one jet size different now where it was 2 jet sizes before ( we use the Comp Jets ).
Passenger side bank still has the most fluctuation during the run, but, its not bad at all and way better than before we sent everything to Wilson.
Wilson was really helpful and understood what i was trying to accomplish .
As they hadn't ever flowed anything with a twin blade base plate and center section, I had one sent and they were able to fab the right carb spacer for heads/manifold/carb combo.
Its worked really well for us, i can keep the tune really tight and stay on the number until we get into the really bad sections of Texas summer air quality, might test some oxygenated fuel to help offset Texas air density this year.

The Twin has worked well for us with our specific needs in index racing .
We run throttle blades locked one to one, Iin texas heat/humidity i keep her pretty tight on the lean side ( best et/mph for us) and when its cool and dry, i can add some fuel .
My job on this car is to keep the car on the numbers all weekend so the driver can just focus on driving.

Thanks for the links!

P.S.

Is that an early Bo Laws center section or did someone else play with that design before Bo other than the holley 3 barrel?
Fascinating man!

Reminds me of looking at old Mark Levinson pre amps- grin.

Last edited by RustyM; 02/11/20 10:33 AM.
Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2741886
02/11/20 11:27 AM
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Question for anyone who may know: Is the Twin Blade design more prone to fuel distribution issues than a traditional 4-v carb, even when used w/ annular boosters? (If the answer is "yes", I won't be surprised.)

Re: Pro Systems King Cobra 4150 carbs [Re: BradH] #2742128
02/11/20 11:42 PM
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Brad: In my experience , the answer is no, they actually improved.
Caveat: we are talking about 4150 flange carbs here.
Ours improved again after Wilson had everything and, could have been better according to Wilson but we are space limited for using a carb spacer, Wilson used all the room we had and its just under 5/8.
But moving from the Pro Systems 950 to the Twin gave better plug readings as well as power.
The guys i know of that are dynoing with them aren't reporting anything negative that I recall.
Mark is going to have more data there than I so I will be interested to hear what he has learned on that subject.

fwiw- we set up initial tuning on the dyno where there is no outside/in air turbulence.
We find our jet stagger bank to bank , initial bleed check etc.
Then we finish jetting / tuning at the track .
So far, right to left bank staggered jetting has been the norm with any carb/intake/ engine combo we have dynoed/tested and thats helped distribution/power quite a bit in some cases.
I have not tried staggering bleeds yet, but i'm gonna try it and see what happens- grin- i just gotta see what i can do on fine tuning . Might be a really bad idea too!

Re: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742130
02/11/20 11:45 PM
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Dom: sorry, didn't see this post and I "think" you were asking me.
I would have to pull out my computer but, if memory serves, we run between 2 and 3 inches at wot, will look tomorrow.

Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2742185
02/12/20 09:27 AM
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Originally Posted by RustyM
Brad: In my experience , the answer is no, they actually improved.
Caveat: we are talking about 4150 flange carbs here.
Ours improved again after Wilson had everything and, could have been better according to Wilson but we are space limited for using a carb spacer, Wilson used all the room we had and its just under 5/8.
But moving from the Pro Systems 950 to the Twin gave better plug readings as well as power.

My thoughts as to why there might be distribution issues is pretty simple: I look down from the top of the carb and I see a potential "dead zone" in the gap between the boosters for a single blade. It would be interesting to see extensive velocity probe readings from the same intake manifold being flowed with both a Twin Blade and conventional 4150... even better would be comparable CFD analysis. scope & work

What work did you have Wilson do, and on what intake manifold? Pics? grin

Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2742247
02/12/20 12:50 PM
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I consider that a problem and a restriction Rusty having 3 in of vacuum at wfo.............less power potential no matter what "charts" or theories say and the ONLY way to know for sure is to try a bigger carb. I love it when people say "But on the DYNO it did this or that and the Dommy only made 7 hp more than an 850......lmao.....EVERY time I put bigger carbs on MOST motors they go faster.....WAY faster in some cases like Jeff Sausier, from 10.60's to 9.90's w/a Dommy I did, then there's the pump gas 3430 lb Chevelle that went from low 9's w/an 1150 before I modded it to 8.90's then a best of 8.84 at 150+ w/a 1250 I did............Real world testing, not dyno mumbo jumbo......

Last edited by Thumperdart; 02/12/20 12:51 PM.

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: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742262
02/12/20 01:31 PM
02/12/20 01:31 PM
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Unless the rules require it or you want a choke, there is No reason EVER to run a 4150 Carb, on any Street/Strip - Race Motor. A Dominator will Always be Faster. And, don't buy the "Too Big" arguments. Tuning/Boosters can be changed to tailor the air flow requirements. Also, Patrick states in the ad for those new Carbs that they are targeted for 4150 Only Carb Rule applications.

Re: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742412
02/12/20 08:11 PM
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Iv'e never seen a car run zero vacuum , not and run.
1 to 3 inches is the best i have ever seen personally.
Our data system doesn't actually read in inch's of hg , but in negative pressure , so, using the math formula after looking at our data as i stated i would, we rum 1.2 to 1.7 inches of vacuum , which, to be honest, is down in the area where the +/- of accuracy on the graphs and data gathering , its impossible for us to be anymore accurate that that.
I would love to try a 1400 on the car and see what that would do but, money is money.

Re: Pro Systems King Cobra 4150 carbs [Re: STEFF] #2742421
02/12/20 08:57 PM
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STEFF: Agreed 4500 carbs are better- thats been well covered i think .
For the guys that run classes where those are not allowed, one can either stop racing, change car and class or- look at every opportunity to squeeze as much as you can out of your combo.
There are very, very fast cars/boats etc running 4150 flange carbs and cfm's at or above 1450 na.
fwiw

Re: Pro Systems King Cobra 4150 carbs [Re: BradH] #2742433
02/12/20 09:45 PM
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Brad: There is no conventional center section or , wall between the boosters on a twin blade , only between mains and secondaries.
Depending on how one wants to build one, you can have standard 4150 range of boosters or, 4500.
To date, I have never heard of anyone having any distribution issues outside the normal ranges and, often less.

Wilson: We got their full Race port job done on an Indy single plane 4150 max wedge intake , cannot recall the part number at the moment.
What does indy do to it- well, they don't really tell you, but it no longer looks like the intake you had.
I can tell you they lower the floor, raise some runners, change the runners at entry, change the curve under the flange and everything is done by flow/fuel distribution as everything is flowed "with the heads" being there- we had to send the heads as well as intake .

Our plugs are amazingly consistent compared to what we had before porting.
Andy has done the same thing on some of his builds- the 470 build was the first one I had seen- its drop dead beautiful work.

We needed better flow, we needed better distribution and, Wilson confirmed my calculations for 1200 to 1300 cfm needed , not to say more would help.

We have great velocity through the intake into the heads , car is very throttle responsive and, we went from 6.72's to 6.36"s pretty quickly .
It allowed us to change gearing/converter , we added better shocks etc.
We are quite happy with the carb/intake .
Next will be a little head work, different cam so we can get 60ft times down a little more.
we are at 3440 lbs and average a 1.38 60ft, best has been 1.36 but, we didn't get to run in any cold/dry air last fall, might have pulled a 1.34 in good air.
I would like to see the car in the mid to upper mid 1.20's

I honestly don't understand why folks seem so anti something different, such as a twin bladed carb or aftermarket efi etc- imho, innovation is generally a good thing and, the more things people engineer and try, the better things get for everyone over the long haul.

We have been very pleased with our twin bade carb, it does what its supposed to do for us, it runs very clean , idle and driving in the pits is clean, we don't foul plugs etc and we have the cfm we needed.
We have custom built 950"s, we have a Pro Systems 950, we have a 4500 , but rules prevent us running a 4500 and the twin vastly out performs our 950's which are very good carbs themselves.

Hope this helps.
But no, no one that i know of has had any distribution problems with a twin.

blessings.

Re: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742441
02/12/20 10:19 PM
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Dyno time is important to many of us Dom.
1. We want to find any issues on the dyno rather than on the track, hopefully find and fix before it costs a butt load of money. I generally budget for dyno time as part of a build.
2. Its an important "base tune" tool and, often, we can find power quickly that we might have left on the table otherwise or, for quite a while . Its nice not having to wonder if a converter is holding us back or, wind sheer etc.
3. We can know factually what timing range the engine likes, we can quickly and easily test different fuels , lash , header sizes etc.
4. We can spend some quality time looking at the carb as a data plot, seeing every little change in afr across the pull as well as air flow and fuel load, trying different spacers, carbs etc.
5. because we have a plotted tq curve and hp curve we can make converter/gear decisions a bit easier.
Its a tool and, imho, a very good one.
I enjoy dyno days- though they are exhausting - im always quite tired when we are done.

Then its all about car assembly and off to test and tune and, imho, "test n tune " goes better/faster because we have gotten some good pre-production work done, have data to reference and thus engine/carb/chassis tuning can be rather structured- at least, it works well for me and , knock on wood, i haven't missed my projected numbers by much or very often and, i'm still learning - hopefully!

My friends here , some who won championships in 2020 follow the same methodology and i'm fortunate enough to be asked to help with the tunes on those from time to time.
But basically: if your building for 800, 900 hp or up, its really nice to know if your built hit the numbers , if not, why and, if so- where you are before you start actually tuning the race car, boat, etc.

Its just another tool for me, nothing more, just helps us match expectations to outcomes as quickly and cleanly as possible.

I reckon everyone figures out what works best for them, gives them what they figure is their best chance for success.
We are soon to start on a little 500 hp Ford engine for a customer and it will go straight to the dyno to test, check for leaks, make sure we don't have any problems , can select the drivetrain values etc before installing everything in a new build - if we have any issues, i want to find them before the final build of the car.

Hope this helps.

Re: Pro Systems King Cobra 4150 carbs [Re: RustyM] #2742577
02/13/20 01:56 PM
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I agree that dyno's have their place and are a great STARTING point but by no means the end all. And when I hear fast68 say a Dommy only picked up 7 hp on that big motor, Stevie Wonder must of done the tune up......Hell, ask Dragula how much my 1250 picked up on a HEMI his friends were struggling with on the dyno compared to a 6-pack and house 950 4150.....like 40+ on tq and hp. Another example of real world, A friend helps crew on a Ford Falcon w/a stout 850+ hp 440+ cubic inch small-block and after and all day dyno session w/Steve Brule at WESTECH, it went 9.66 at Fontana w/a crappy 1.42 60 ft then they put on a blp billet 1050ish I built and with zero tuning went a 9.12 w/a 1.29 60.......There's many more but you get my point.........And getting back to the twin Rusty, I asked for a Dommy twin and he sent me that carb which I KNEW was too small and it proved to be on my junk anyhow.......


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: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742579
02/13/20 02:07 PM
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Forgot, the same Falcon went 2 back to back 8.90's in Bowling green Kentucky at a race foot brakin, didn't even use the trans brake yet.....Videos on my FB page.....


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: Pro Systems King Cobra 4150 carbs [Re: Thumperdart] #2742610
02/13/20 03:59 PM
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No qualms with 4500 being better, more efficient etc.
No qualms with with your position on that company- we share that position.
I don't blame the technology the Law boys created on the company selling some of them and, guys that have no choice but to run 4150 units have to find the best answers they can - thats all.
I would personally rather have 4150 with boosters than one with spray bars and, for wot competition the twin meets a lot of needs.
Now that there are parts available from other companies for the builders the issues we dealt with don't have to be an issue at all.
I cannot deal with Indy Racing heads- tried, its basically the same deal as we went through- it was "stick a fork in me, im done " real quickly.
That said, we do use some Indy parts- we just don't call indy .
I can appreciate the technology without dealing with lug heads.

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