Opinions-ideas Single Ports Vs Ports And Dribblers

Plumbing Up A Psi Screw On A Doorslammer, Was Going To Try Going The Single Line-nozzle For The Ports,to Keep The Plumbing A Little Cleaner. We Always Ran Single On The Whipples
Whats The Opinions On Single Vs Duals For This Application????

 

My guess dribblers are for when you can't get your pump pressure up at stage, shuch as when you run a glide. Maybe as a last choice for even stage EGT

 

I think many racers use the dribblers as a fine tuning adjustment for staging. But there are times and race tracks where having the car leave with even EGTs isn't necessarily a good thing. One advantage of single nozzles is that it ends up being fairly large. It is alot more difficult to plug up a 80 nozzle than a 39 and a 65 nozzle. So it gives some safety margin if you get junk in your fuel. On the other hand a increase of one or two sizes when you re in the 80-90 range is a bigger flow jump than if it was a smaller nozzle. Sometimes you might want to richen or lean a cylinder a dab- its harder to do that when your nozzle is a bigger number. So both systems have advantages and disadvantages. And both systems will work just fine. I have ran both and I like the flexibility a 16 nozzle sytem offers. I am sure you will hear a ton of opinions on the subject. Good luck on figuring out what is important to you and what isn't. Dave Germain

 

Shawn,

I think you are going to want to run some amount of hat nozzle to keep your rotors sealed and lubricated.

EDB

 

Nozzles

Yes We Are Going To Do The Standard 4 Nozzles In The Hat

 

I don't understand why you would want the EGT different at launch. When I was at the Hawley school, this is the condition they had in the dragster motor. It appeared they were only concerned about matching EGT when the car hit the finish line. If you are trying to de-tune the motor a bit, couldn't this be adjusted with the fuel curve? It was very interesting to see the wide range of jet sizes they had in the intake manifold, apparently compensating for some very nonuniform airflow under the supercharger.

 

For years in the top fuel motors they would run different length connecting rods and different compression height pistons in some cylinders to try to even up the EGTs. You would be amazed how different cylinders get different amounts of fuel/air. That explains the different nozzling to each cylinder. As for some cylinders running hot and others cold at the starting line- it depends on the race track. Some tracks will not handle all 8 cylinders firing evenly. If you ask guys like Randy Anderson or Les Davenport they will tell you the same thing. Maybe a national event prepped track will but many division event tracks won't and you will just end up shaking your fillings out of your teeth 100 feet out. As an example when I run at Spokane I richen three cylinders to be cold at the starting line. They clear out by a few hundred feet out and the car goes down the track fairly well. There are a few more little tricks to try also but that one is easy and it only requires a few nozzle changes. Dave Germain

 

Wow, that is really interesting. This discussion reminds me of an engine Honda developed back in the 1980's for their GP motorcycles, called the Big Bang motor, I believe. The problem was somewhat similar in that it involved tire slippage. Riders enter a corner at and above the limits of adhesion and deliberately initiate rear tire spin to square off the turn. The idea was that a road racer would corner like a dirt bike.

If the tire broke completely loose, however, the bike slips too much and slows cornering speed and may even initiate a crash. The Big Bang motor gave the rider fine control of rear tire spin by use of the throttle.

The essential idea is asymmetric power delivery on the crankshaft rotation. On their usual 4-cylinder, 2-stroke motor, a cylinder would fire every 90 degrees of crankshaft rotation. The Big Bang had a different crankshaft that pushed cylinder firing much closer together, leaving the motor silent for an extended portion of crank rotation (how much I don't recall). This allowed the tire to re-hook and slide much more predictably.