need help with my carb

[302crew]

i need help with my carb ive had fuel injection for years and i now decided to go fuel injection basicly i dont know **** about it I have the car running but i just dont feel its running like it should basicly i just took the carb out of the box bolted it on and thats it i dont know what to put my fuel pressure at or what to adjust so if anyone can help it would be very apriciated this is my setup mighty demon 650 carb with clear sight bowls and mechanical secondaries rmp air gap intake edelbrock 6037 heads long tube headers 306 bottom end xtreame flow air filter msd ignition 373 gears custom cam and 1.7rr. Also if anyone could give me some suggestions about where my oil is comming from would help i beat on my car and oil comes down the back of the oil pan i changesd the rear main seal and i also checked the intake and valve covers and there dry but its just when i run it hard thanks in advance for any help.:cool:

[RoadWarrior]

Ok lets see if i can help out here. As far as fuel pressure goes 5-6psi is all most carbs need to do their job. As far as adjusting your carb goes first thing id do is read over the manual. Carbs can be finicky to work on. Going from there you shouldnt have to do much to get it set up properly. Just fine tune the mixture a bit. I could tell you how exactly its done but it will say it all in the manual and probably better than i can.

[jim_howard_pdx]

Doing high performance tricks with a fuel injected car always seems to be a disappointment. Either the computer fuel curve, the fuel rail pressure, or the injector size needs to be fiddled with, and each effects the other so eventually you end up hot rodding all three!!!!

If your Stang had factory horsepower, you are probably running a 110lb hour fuel pump delivering 40 PSI. This will basically turn your Demon carb into a gasoline fountain.

You will want to run a pressure regulator, with a guage!!!! and make sure you set it to provide no more than 7 lbs pressure at WOT. I like 5-6 just to be safe. If the inlet needle is forced off the seat, fuel rises and gets sucked raw into your intake. Rarely will this damage the motor, but it sure does make for great fires.

The Demon probably is running double downleg HP boosters. Check to make sure. I would jet the primary at 68 and the secondary at 72. Set the power control valve at 6.5.

If this is going to be a street highway car, I would change the front boosters from double downleg to annular. That way the primary circuit will come in sooner, and you will atomize fuel off idle almost as effectively as fuel injection. This is what I do with my modified Holley. Annular boosters up front and double downleg HP boosters in back.

I would lose that mechanical secondary carb. Go to a Holley 750 and contact me again. I will help you modify it for your rig. The Demon carb is for quarter miles and circle track. It is not a good street/ highway carb.

For a strictly racing carb set up, I like to run two 75 gallon fuel pumps and two 1/2 inch fuel lines from the tank and individually feed the primary and secondary fuel bowls. I run the pressure at 4-5 lbs. This will feed a 500-700 HP engine safely. It also makes feeding the NOS monster easy, since you can just boost up the secondary pump rating to match the HP you are tuning for.

If I hear one person say this is overkill, then when have you run 8 to 9 second quarter miles? Sit down, shut up, and hold on.

Before you give up on the fuel injection. You should try the new trick flow upper and lower intake with the 90 mm MAS, a good chip, and 36 lb injectors. That should get you from 350-500 hp and be great on the street. I port the intakes on all my race cars. I like the ports to be 1 5/16 wide by 2 1/8 tall. This is very close to CJ 428 size, and should support 400+ horsepower.

When you add nitrous, a 200 HP boost will make you want to go through NASA training- I KID YOU NOT. :cool:

[302crew]

well i have a holly black fuel pump with a regulator i just need to know how to adjust the damm thing

[JaxTheDJ]

Originally posted by 302crew
well i have a holly black fuel pump with a regulator i just need to know how to adjust the damm thing

First,get a fuel pressure guage,preferably a liquid filled one,then use teflon tape on the threads and screw it in to the regulator,once you have done this and mounted it look for the hex head screw on top of the reg. screw it clockwise to lower and counter clockwise to raise,I set mine at 7 & 1/4 lbs of pressure and it works fine.

[RoadWarrior]

To adjust the pressure on a holley regulator all you do is loosen the locknut on the top and adjust using the allen key. But like jim said get a fuel pressure gauge. Personally i prefer the liguid filled ones but just get a gauge. And then set it at 5-6psi. Like jim said the street demon is probably a little more carb than you need. i would have gone with a 650 dp. And like i said READ THE MANUAL.

[Eric4Nitrous]

all above answers are good advice. Carbs are tricky and can be a hassle if you don't know what your doing. By the way, why the hell do you have the "black" pump on your car? It's made strickly for Alky.

[302crew]

well i have the gauge and the pressure is set i need to know how to tweak out the carb basicly like right now i have the sight bowls at about half way becouse there the clear ones and i have the 4 screws on each side of the bowl turned a turn and a half out from the bottom and the timing is set at 14and the fp is at 7 heres the thing when im beating on the car and i shift it into 5th it dies has no power and also when i downshift and go it bogs hard before it goes. could this be cause my motor didnt fit under the hood so i just cut a hole in it temporarly and its getting to much air or 2 could my valves be out of adjustment and 3 i put my cam in and lined the two dashs up by eye and here is the thing my cam card siad these specs are for a cam installed at 108 intake center line did i install the cam wrong.
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