Re: Switched to a smaller CFM to slow car...........
[Re: J_BODY]
#2694247
09/04/19 09:27 AM
09/04/19 09:27 AM
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Joined: Feb 2003
Posts: 2,560 S.E. Michigan
cl440
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That is interesting.... in most cases it seems to make a difference. What’s the Venturi size and throttle bore size on the 4150? Throttle bore is 1-3/4" Not sure on the venturi size
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Re: Switched to a smaller CFM to slow car...........
[Re: Clanton]
#2694248
09/04/19 09:29 AM
09/04/19 09:29 AM
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Joined: Feb 2003
Posts: 2,560 S.E. Michigan
cl440
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I have seen some restrictor plate kits that work well you can look into using We were looking at the EZ plate system. Decided to go new smaller carb instead since our dominator is old and we would probably need a new carb eventually anyway. Jokes on us! LOL
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Re: Switched to a smaller CFM to slow car...........
[Re: cl440]
#2694256
09/04/19 09:38 AM
09/04/19 09:38 AM
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Joined: Feb 2003
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cl440
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That is interesting.... in most cases it seems to make a difference. What’s the Venturi size and throttle bore size on the 4150? Throttle bore is 1-3/4" Not sure on the venturi size I just found on the web if it's correct........1.45 venturi
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Re: Switched to a smaller CFM to slow car...........
[Re: tboomer]
#2694269
09/04/19 10:22 AM
09/04/19 10:22 AM
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Joined: Mar 2003
Posts: 916 SE Washington
Forest
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Chuck..I think someone here recommended the ET Genie...Pretty expensive but it works well. The EZ Plate company is out of business. I bought the ET Genie for my wife's car so she can run Sportsman 12.0 and slower. Her car has ran 10.97 with it wide open. You check your settings with a dial indicator so you can really dial it in. Last weekend at Pacific Raceways I had it running 12.02 all out. That way the car is still full throttle, normal timing, normal shift points etc. Probably a bit overkill for what you're trying to kill but just thought I'd offer my experience.
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Re: Switched to a smaller CFM to slow car...........
[Re: Forest]
#2694289
09/04/19 11:06 AM
09/04/19 11:06 AM
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Joined: Feb 2005
Posts: 20,174 PA.
pittsburghracer
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Ask yourself is this a long time solution or a short time solution. Are you going to upgrade the cage to 7.50 over the winter for both safety and room to go faster
1970 Duster Edelbrock headed 408 5.984@112.52 422 Indy headed small block 5.982@112.56 mph 9.42@138.27
Livin and lovin life one day at a time
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Re: Switched to a smaller CFM to slow car...........
[Re: cl440]
#2694360
09/04/19 01:48 PM
09/04/19 01:48 PM
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polyspheric
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A possible reason why the car works well with less CFM: the A:F curve raises faster with the closest jets due to higher vacuum. Perhaps a bit rich was helpful?
Boffin Emeritus
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Re: Switched to a smaller CFM to slow car...........
[Re: polyspheric]
#2694383
09/04/19 02:40 PM
09/04/19 02:40 PM
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Joined: Jan 2005
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HotRodDave
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what about retarding timing a few degrees? Seems all the OEMs are doing it during tranny shifts to cut power and make trans last longer. That would keep all your shift points exactly the same and not increase the chance of tire spin from more TQ down low when the weather gets real good.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Switched to a smaller CFM to slow car...........
[Re: AndyF]
#2694394
09/04/19 03:44 PM
09/04/19 03:44 PM
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cl440
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What intake do you have? If you had a Dominator on a 4150 intake with an adapter then you might not have lost any power. If you put a 4150 on a 4500 intake then you probably lost some power but you might have picked up some torque down low so the car goes just as quick. If you changed intakes at the same time as the carb then you have two variables so anything could happen. Hi Andy! This is what I needed the adapter/shear plate for that I got from you. Same 4500 intake all I did was bolt on the shear plate and the new 4150 carb. 60' numbers are the same. In fact all the incremental numbers stayed the same. Maybe my 4500 carb wasn't as good as I thought it was or the new 4150 is just really, really good?
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Re: Switched to a smaller CFM to slow car...........
[Re: HotRodDave]
#2694395
09/04/19 03:48 PM
09/04/19 03:48 PM
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cl440
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what about retarding timing a few degrees? Seems all the OEMs are doing it during tranny shifts to cut power and make trans last longer. That would keep all your shift points exactly the same and not increase the chance of tire spin from more TQ down low when the weather gets real good. Currently pulling 5 degrees at launch and ramping back in over 2.5 seconds. I may pull some more. Heading to Indy for division 3 finals next weekend. The cut off for that race is 5.40 (1/8 mile) I may be just fine but would hate to get tossed if I click off a 5.39 on a pass!
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Re: Switched to a smaller CFM to slow car...........
[Re: cl440]
#2694403
09/04/19 04:03 PM
09/04/19 04:03 PM
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Joined: Jan 2003
Posts: 31,034 Oregon
AndyF
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What intake do you have? If you had a Dominator on a 4150 intake with an adapter then you might not have lost any power. If you put a 4150 on a 4500 intake then you probably lost some power but you might have picked up some torque down low so the car goes just as quick. If you changed intakes at the same time as the carb then you have two variables so anything could happen. Hi Andy! This is what I needed the adapter/shear plate for that I got from you. Same 4500 intake all I did was bolt on the shear plate and the new 4150 carb. 60' numbers are the same. In fact all the incremental numbers stayed the same. Maybe my 4500 carb wasn't as good as I thought it was or the new 4150 is just really, really good? Or maybe that shear plate really works! I guess it is hard to say for sure without getting it on a dyno. It is possible that your 4150 carb is working better than the 4500 carb. Usually a good 4500 carb will pick up 20 or 30 hp over a good 4150 carb but when you compare any two carbs the results can vary all over the map.
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Re: Switched to a smaller CFM to slow car...........
[Re: AndyF]
#2694409
09/04/19 04:17 PM
09/04/19 04:17 PM
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Joined: Feb 2003
Posts: 2,560 S.E. Michigan
cl440
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What intake do you have? If you had a Dominator on a 4150 intake with an adapter then you might not have lost any power. If you put a 4150 on a 4500 intake then you probably lost some power but you might have picked up some torque down low so the car goes just as quick. If you changed intakes at the same time as the carb then you have two variables so anything could happen. Hi Andy! This is what I needed the adapter/shear plate for that I got from you. Same 4500 intake all I did was bolt on the shear plate and the new 4150 carb. 60' numbers are the same. In fact all the incremental numbers stayed the same. Maybe my 4500 carb wasn't as good as I thought it was or the new 4150 is just really, really good? Or maybe that shear plate really works! I guess it is hard to say for sure without getting it on a dyno. It is possible that your 4150 carb is working better than the 4500 carb. Usually a good 4500 carb will pick up 20 or 30 hp over a good 4150 carb but when you compare any two carbs the results can vary all over the map. No doubt that plate works good and was exactly what I needed to adapt the 4150 carb to the 4500 intake. Like I said maybe that Dominator has more in it. I really believe that Quick Fuel 4150 carb is really really good though (Obviously)!
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Re: Switched to a smaller CFM to slow car...........
[Re: cl440]
#2694493
09/04/19 09:45 PM
09/04/19 09:45 PM
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Joined: May 2003
Posts: 13,189 aZLiViN
J_BODY
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That is interesting.... in most cases it seems to make a difference. What’s the Venturi size and throttle bore size on the 4150? Throttle bore is 1-3/4" Not sure on the venturi size I just found on the web if it's correct........1.45 venturi Interesting..... of course I’m running VP C12 fuel, but my 1050 seemed to wake my car up quite a bit from a 1.48 Venturi 1.79 4825 Braswell (4150 based) carb.... just wish I hadn’t swapped the 727 to the 904 at the same time so I could really tell how much.
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Re: Switched to a smaller CFM to slow car...........
[Re: J_BODY]
#2694672
09/05/19 11:56 AM
09/05/19 11:56 AM
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Joined: Jan 2003
Posts: 19,363 Las Vegas
Al_Alguire
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Just pull timing the entire run. We do it with our dragster as my son can only go 7.50 and the car will run 7 teens in Vegas. In fact we pull 12 degrees the entire run and use a small 1050 on it here in Vegas. The carb alone is worth .25 on the 572
As for your results I would be willing to bet it is a tune issue more than anything. Most dominators OOTB tend to be PIG fat throughout the RPM band which is NEVER fast. Pulling a vacuum test on the dyno will tell you if it is to big of a carb or just a tuning issue. We run VERY large carb on the 572 on the dyno compared to what its raced with
Last edited by Al_Alguire; 09/05/19 11:59 AM.
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Re: Switched to a smaller CFM to slow car...........
[Re: Al_Alguire]
#2694718
09/05/19 03:43 PM
09/05/19 03:43 PM
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Joined: Feb 2003
Posts: 2,560 S.E. Michigan
cl440
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Just pull timing the entire run. We do it with our dragster as my son can only go 7.50 and the car will run 7 teens in Vegas. In fact we pull 12 degrees the entire run and use a small 1050 on it here in Vegas. The carb alone is worth .25 on the 572
As for your results I would be willing to bet it is a tune issue more than anything. Most dominators OOTB tend to be PIG fat throughout the RPM band which is NEVER fast. Pulling a vacuum test on the dyno will tell you if it is to big of a carb or just a tuning issue. We run VERY large carb on the 572 on the dyno compared to what its raced with We were just talking about pulling it for the entire run. We may try this. Thanks!
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Re: Switched to a smaller CFM to slow car...........
[Re: cl440]
#2694951
09/06/19 12:18 PM
09/06/19 12:18 PM
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Joined: Mar 2003
Posts: 1,449 Martinsville, IN
cdwmotorsports
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HotRod's Frieburger and Dulcich plus Steve Brule on the Motor Trend Engine Masters tested the affects of too small or large of a carb and too much or little timing on performance and the carb mattered the least timing was the power killer. If you can find the episode its well worth a watch
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