Trick carb down 50 hp

[Doug Schriefer]

Looks like the Braswell baseplate has the extended ears that fit a 4500 pattern. I put one of those baseplates on a hp1000. Pretty slick deal, just had to trim the 1/2" phenolic spacer on the outside where the accel pumps and throttle arm were rubbing. I can swap my 4500 out for the 4150 and don't have to change spacers (less variables).

All of our new Severe-Duty baseplates are slotted to fit either bolt pattern.

[cpmotors]

A few things:

First NEVER just put the same jets from one carb into another (that are built and calibrated differently) Based on how they are designed this could be dangerous.

Good catch Doug- I think thats directed at me. I should have stated the that the A/F numbers indicated an extremely fat condition, hence the downsizing on the jets after the comparison to the old carb.

[Doug Schriefer]

A few things:

First NEVER just put the same jets from one carb into another (that are built and calibrated differently) Based on how they are designed this could be dangerous.

Good catch Doug- I think thats directed at me. I should have stated the that the A/F numbers indicated an extremely fat condition, hence the downsizing on the jets after the comparison to the old carb.

I wasn't pointing at anyone, I just hear this alot "Well I'm going to put the same jets in as I used to run, or as my buddy runs before we start"... I always cringe... Especially when you're looking at stuff with different calibrations.

[harry k]

i have a Dynojet 2000+hp chassis dyno tuning shop , and couldn't resist not to reply after reading this thread .

race cars come in time & time with "MEGA $ DOLLAR" tricked out carb from some highly recomended source/builder in the industry,soon as they remove fiber hood out and i see them , the thoughts back of my head tell me lets see,
now how is this guy gonna end up with !

anyways,being a general dyno shop that does testing/tuning on all makes and cater mostly to drag cars,the ratio of what i see is 50/50 some success and lot of dissapointments for customers that have to come back to pay for tune all over,specially new racers getin into sports where they don't understand "yet" what it takes to do it all to make it purfect.

i do have a "dyno mule" dominator that belongs to my race car(that life started as old prostock list 6464 dominator that belongd to Bill Orndroff-Jerry Eckman team,that was tampered/modified by 2 sources in its life span -one is local famous southern ca. shop and other is another board member that frequently visits here installed anullar booster in it for me for better performance,
other than my chassis dyno, confirmed even at Bob Lambeck racing engine dyno that it did get 11more hp over out of box Holley 8896hp carb on a 555ci BB chev.
so it a precious gold for me.
the 2nd carb i keep around is "out of box"Holley 8896hp that i have to compare with with any situations like this arise .

bottom line is: the "out of the box" Holley carbs will do the job ,the person/racer/eng builder who is buying "tricked out" carb if want to experience trial and error ,should be open minded not get frustrated or pissed off cuase it didnt perform 1st time out

another thing to consider is hopefully a local source ,so when problem arises easier to work with
and next thing whats the tricked out carb gaurantee that they offer? any ???
best experience i had was with http://www.candsspecialties.com/abcmods1.html ,no question asked 30 days money back gaurantee on their carbs
as stated in thier site "As always, we are available to consult on dyno test setups, carburetor selection, or other fuel-system issues, free of charge"

[Brian Rock]

We still don't know if this unit was even built for this specific engine, or if the builder was even called.

Not fair to put up a post and stir the pot, then not give us the rest of the story.

[Mike Laws]

At the risk of being redundant; I'd like to say that it is very important for the carb-builder to get as much information as possible about the engine, transmission, car, type of racing, climate, etc. Error on the side of too much information and you'll probably be just right.

[andyf]

At the risk of being redundant; I'd like to say that it is very important for the carb-builder to get as much information as possible about the engine, transmission, car, type of racing, climate, etc. Error on the side of too much information and you'll probably be just right.

I can see the need to provide a carb tuner with specific information for a specific car but I've also worked with plenty of carbs that run great regardless of the motor they're put on. We have a few dyno carbs that make excellent power regardless of the motor they are put on. (within reason of course). Often times a great dyno carb can be moved from motor to motor and make more power than the customer's carb without doing anymore than adjusting the main jets up or down a few sizes.

On the other hand, I've seen a few carbs that won't work regardless of what motor they are put on.

[RayJE Carburetors]

a carb mightnt make more power on the dyno but will be quicker under a dynamic situation at the track as well.

as with engine builders and cylinder head porters .....there are good and bad... same with carb guys


its the last thing to bolt on and first thing to get blamed


dont persicute some carb builder becasue a carb has his boosters or for that mater has his sticker on the bowls ........... i had an example here a few months back where i was called over to a dyno session becasue one of my carbs wouldnt pull up on the brake.....when i got there i looked at it and knew it wasnt my work... i saw my stickers on the bowls and then put 2 and 2 togther....... a few weeks earlier the engine builder asked me for replacement stickers for bowls as he said he had some peel off.

[Arthur]

There are no surprises here, you can have a "Dyno carb" that makes you feel good or a "Track tuned carb" that is good.
It's just that its quicker to get a result on the dyno,one way or the other.
Convenience usually rules, unfortunately.

[jmarkaudio]

At the risk of being redundant; I'd like to say that it is very important for the carb-builder to get as much information as possible about the engine, transmission, car, type of racing, climate, etc. Error on the side of too much information and you'll probably be just right.

I can see the need to provide a carb tuner with specific information for a specific car but I've also worked with plenty of carbs that run great regardless of the motor they're put on. We have a few dyno carbs that make excellent power regardless of the motor they are put on. (within reason of course). Often times a great dyno carb can be moved from motor to motor and make more power than the customer's carb without doing anymore than adjusting the main jets up or down a few sizes.

On the other hand, I've seen a few carbs that won't work regardless of what motor they are put on.

I guess the question everyone is asking is why you were changing air bleeds and not jets to get the mixture close? Why was the jetting it came with not tried first, rather than matching jets with the other carb? And with the advent of AF meters, unless a carbs venturi has been worked on/messed up, I would think any carb can be made to work if you take the time to straighten it out.

[andyf]

I also think that any carb should be able to be made to work. That is what the engine builder and I kept telling each other when we worked on this carb!

We're going to be testing another motor on the dyno in the near future with a 4500 flange so we might give this problem carb another try. Not sure what we'll try next as most everything has already been attempted but maybe if we stare at it long enough we'll think of something clever to try.

[bigjoe1]

I have never seen a TRICK carb run any better than some of the carbs I have on the shelf for dyno testing. Many times they make way less HP ( 30-40)Only once in a while will the trick carb match my dyno carbs. I realize this does NOT show the driveabilty of the carb, but only the full throttle performance.

JOE SHERMAN RACING ENGINES

[John W]

There are no surprises here, you can have a "Dyno carb" that makes you feel good or a "Track tuned carb" that is good.
It's just that its quicker to get a result on the dyno,one way or the other.
Convenience usually rules, unfortunately.

I agree. I've yet to have a "dyno tune-up" run the quickest down the track, especially a chassis dyno tune-up. My car always wants more fuel and less timing when I get to the track.

[Doug Schriefer]

I also think that any carb should be able to be made to work. That is what the engine builder and I kept telling each other when we worked on this carb!

Andy, this is a VERY dangerous statement.... When dealing with race carburetors that are built for specific combinations they are not always going to work on other engines...

[Doug Schriefer]

I agree. I've yet to have a "dyno tune-up" run the quickest down the track, especially a chassis dyno tune-up. My car always wants more fuel and less timing when I get to the track.

The dyno and the race track are different... No matter what, you're going to need a different tune-up from the dyno to the race track to get optimal performance regardless of who built the carburetor, or tuned it.