Basic fuel setup

Hi all!
We are a swedish team that going to make a change to our fuel system.
So far we have only run 8 hatnozzles. They have all been 0.052.
Now we want to use hat and portnozzles.

What would be a good basic setup?

-Chevrolet Big Block 460 cui.
-Big Brodie heads
-BDS blower, 8/71
-Enderle 110 pump (13,2gpm)

 

Call Mike at RAGE FUEL SYSTEMS 843-623-3500. Do yourself and your pocketbook a favor and pay someone who knows what they are doing to flow your system and get you a good baseline tuneup. Ask John Force racing, Suchmacher racing, and Kallita racing how they like his pumps....

 

Speak to Spud Miller at Fuel Injection Enterprises
http://www.fuelinjectionenterprises.com/

One of the nicest most helpful guys I've ever dealt with, definitely worth getting things flowed by him and he'll see you right for a baseline.

 

Need more info than this to assist.

What overdrive?
What barrel valve?
Clutch or auto?
How fast do you want to run?

 

The overdrive is 22% and the blower makes about 21 psi.
The barrelvalve is a K-Style.
Our converter is set to stall at 5800-5900 rpm.

Since this setup is new to us we try to run about 7.5

 

OK to start you will be able to run smaller in your hat, .052 will drop the system pressure.

I'd go with 8 x .040 or .042 in the hat

Set you idle check valve between 6-8lbs

Set your port check valve to 18-20lbs

If you want to run a high speed for now play it safe, set it to 60lbs and use a .050 pill

as for port nozzles from the front go around

44 44
42 42
40 40
40 40

I wouldn't advise going smaller than 40 as easy to block

As for where to start on your main pill - what do you use now?

 

With the eight .052 in the hat we have run a 125 mainjet and a high speed.( 95@90 PSI)

Maybe a stupid question but... Should the portnozzles be abut the same size as the nozzles in the hat? I have no experience so please give as much info as possible.

In your example the total area of the nozzles are much bigger than the .052
Is this OK or should I calculate the same total area?

 

Total hat is 0.01108 Sq In

Total port is 0.01083 Sq In

Little bit more up top wont hurt as lubes the blower.

You also should add a pump saver, this is just a check valve set fairly high usually 140lbs+ so that when you lift top and it opens and the fuel has somewhere to go...we dump it in the blower only, lubes it top end.

 

With the new setup we removed the returnline for the pumpsaver from the tank.
Now it is set to the hat nozzles.

The idle chek valve is set to 9 PSI and the port check valve to 15 PSI.
Could any of these settings make the exhaust temp uneaven dunring idle.
Now the heads are much cooler (richer) in the front.

 

During the weekend we tested the new setup on the track. It is very simlar to your suggestion and it works well. After reading the plugs small changes were made.

Thank you! It was wery helpful.

 

Sorry I have not replied sooner. Glad it worked well for you too - it would of needed a little bit of tweaking as wouldn't of accounted for how good your blower is etc

What did it run?

 

Fuel will do this a little as above is richer at front to account for blower pushing more air to the front.

Also remember BBC's have siamese intake ports, so it will affect temps quite a bit - if you look at the head from above, the right port of each pair is longer and flows better, the port on the left is shorter and just doesn't flow as well (Chevy design!)

Also would be worth checking injector, reseat butterflies and readjust

 

It was a rainy weekend so we got only one run. There were problems at the start with the timing tree and outr driver got no start RPM. After 1/8 mile he drifted to the right and hit the fotocell at 1/4 mile. So no ET.

The only good data is the speed at 1/8 mile.
145 mph in our car is about 7.5 ET. The problems at the start made the 60 fot 0.2 slower than normal.

 

Great thread, building a similar combo but a early donovan I have yet to fire it up but want to setup my fuel system myself, what air gap did you set on the butterflies and what percentage of leaks down are you running? Thanks

 

What injector you using? Depends on size, also what blower?

Generally set between 8 to 12 thou - make sure they are seated properly first.

 

With the new injector the butterflies are set to 0.004" (0.1mm).
(The old injector neede more gap 0.005")

The leakdown was set to 70% before the first startup.
It worked OK. I had to add a little more fuel so the leak is a few % more.

 

Found a picture from the first burnout with the new fuel setup.

http://www.ziken.se/Galleri_Motorsp...dalen Open 1/content/D2X_2795_copy_large.html

Thanks to Bennettracing...

 

Happy to help.

Great looking car and a cracking burnout!

Also keep me updated with what it runs if ok at info@bennettracing.co.uk

 

Pro-Calc jetting program analysis

Your 8 nozzle baseline was entered into our Pro-Calc jetting program for a setup with two nozzles per cylinder, one set to zero for the preliminary hat only analysis. An air density of 100% was assumed. A blower volumetric efficiency with 100% was also assumed. That would be a blower with new seals:

1. first with no high speed
--- to get the low speed air to fuel ratio
--- engine speed for a system pressure of 90 psi, your high speed opening point.

See the link: http://airdensityonline.com/images/sten-8-nozzles.jpg

The air to fuel ratio is 3.84 to one. That is 3.84 pounds of air to one pound of fuel. That is a bit rich for a supercharged wedge engine although that depends on the engine compression ratio. An engine speed of 6150 rpm provides 90 psi fuel pressure using our default pressure calibration.

Note: If you have a fuel pressure at an 8,000 rpm engine speed, that value can be entered to calibrate the calculator to your fuel pressure characteristic. If you have a fuel pressure at a lower rpm, that value can be ratio'ed up to an 8,000 rpm value to calibrate the calculator.

2. Then your high speed jet of 95 was entered into your 8 nozzle setup
--- to get high speed air to fuel ratio
--- system pressure at 8,000 rpm with the high speed open.

See the link: http://airdensityonline.com/images/sten-8-nozzles-w-hs.jpg

The high speed air to fuel ratio is 4.76 to one. That is too lean if the air density was at 100% and the blower was at 100%.

System pressure was 99 psi at 8,000 rpm. That is typical of a FI setup although in our 8 nozzle setup, it ran better at 140 psi with the high speed open.

Basically your system goes to 90 psi at 6150 rpm. The high speed begins to open. Your system pressure creeps up to 99 psi at 8,000 rpm with the high speed open.

A lot more discussion can follow just from your baseline. We can adjust hat nozzles down and enter port nozzles in further analysis. We are just now setting up to provide screen shots of our jetting calculator setups. More images to follow.

Bob Szabo
(916) 419 6649
www.racecarbook.com
www.airdensityonline.com
www.airdensityonline.com/pro-calcs/

ps Wew. By the time I was done with this response, I may have lost track of some of the numbers throughout the thred. Give me a break if I did. Nozzle & jetting setup analyses tend to get lengthy from the calculator results.

 

Great help! I think I have to do some more reading.

From other books I made a simple excel documet to calculate blower, weather,pump, mainjet and hat nozzles. It cannot calculate the actual fuelpressure. Last season I got some help from another team to calculate the high speed pressure and jet.

I started this thread to learn more about adding port nozzles but with your help I can see I have to check my AFR again.