Hi One friend of mine's 246 Gt has some fuel alimentation problems while driving in fast curves. Fuel pumps are new. Do you have any idea ?
Classic problem on Dino's on, I believe, left hand turns due to carburetor orientation. There are some light weight floats available which may help but most usually just grin and bear it.
I believe one advantage of using IDF carbs on a manifold from a Lancia Stratos is that their float bowls don't go dry in a turn. There was a fellow on this board who said the parts are readily available--maybe he'll chime in.
All Dinos have the problem. I played with all the "old wives tales" and came up with the following: Weber designed carbs with idea that float bowls would be in front of barrels. Idle jets are on other side of barrels; 1 1/2 inches on the Dino. If float bowls are in front of barrels: Acceleration moves gas towards barrels Deccelaration moves gas away from barrels All is right with the world, rich in accelerating, lean when braking Rich, lose a little. Lean, lose everything. If float bowls are to right of barrels: Left turn is lean, engine dies Right turn is rich, engine sags a little but no biggie. Dino float bowls are to right of barrels: Engine dies on hard left turn. That is the way nature intended. Live with it. Or tell me how to fix it. John
Here you go: http://www.ferrarichat.com/forum/showthread.php?t=41445 Some "knowledgeable" people say this problem only exists in your mind...
Sure, John this should be pretty easy for you to do. The carbs on the Dino were originally designed for a North/South engine orientation rather than East/West, so, simply relocate the engine 90 degrees with the floats to the . . . . . Hmm -- I give up.
Those "knowledgeable" people have never gone over a hill, trailing throttle and into a sharp left turn, at speed, with modern tires. Centrifugal force drains the idle jets back into the float bowls and the engine quits. Punch the throttle and the accelerator pump lights the engine back up but you have had an "Oh ****" moment. Not fun. I have read all the arguments and played with the floats. When you pull close to 1G to the left, no gas gets to any of the idle jets and flame out happens. I quickly learned to plan ahead and can live with it. The only choice short of major surgery. Actually no real problem unless you are racing. Around town and on freeway, at legal speeds, things could not be better. John
After considerable messing with floats, jets, etc, we've gotten MOST of the stumble out of my car, even at speed. 1G in a Dino? Only off a cliff when you contact the ground... :d I'll pull up the invoices and post the changes when I get a chance. dm
So a tire change, on the stock suspension, will take the car from .83G to over 1.0G? Maybe I'm nuts, but I don't see that happening. In 1972 cornering was .83 G in the Road and Track article, which is where I started in my premise that 1.0G+ seemed like a stretch. Maybe with race tires and a tweaked suspension, but I just don't see it stock out of the box making those numbers. dm
Read his post again. He never said he pulls over 1.0Gs. Modern street tires are even better than the best race tires of 1972. So those 1972 street tires were even worse.
What I meant is that you can't say you fixed the problem if you're only running on XWX. Fit modern tyres on 15" wheels and the fuel starvation problem comes back in a flash...
Thanks for the clarification. He said Modern tires or no, you ain't gonna pull a G in a Dino. I've been driving cars forever, and a Dino for 3 years. Mine has every modern suspension upgrade, new XWX tires (I've run others, too), and it's not going to approach 1G. It is a LOOOOOOONG way from .83 to 1G. It's even a long way from "close to 1G." An Enzo pulls 1.05G for comparison. DM
Don't know how close to 1 G but it is more than stock, and stock has problems. I run wide 16" wheels with 205 front and 225 rear. 2" to 3" wider rubber patch than stock. Car sticks. Point I was making is this: If you accept that centrifugal force and body roll are added to the force of gravity, it is the same as tipping the carbs more than 45 degrees to the right. Idle jets are on the left of the barrell, float chamber is on the right, 1 1/2 to 2 inches away. The idle jets are effectively lifted way up and gas a hard time going uphill. Engine goes lean. On the other hand, Main jet is on the right, right next to the float and is hardly affected. But; Main jet does not work at all until butterfly is about half open so you have to plan ahead and be quick on the throttle to work through the turn. John
Does anyone have exploded diagrams of DCNF and IDF's? Looking at the IDF's I get the impression the float bowl sits between the bores rather than to the side of them. The only places I have long turns around me are freeway onramps, and they all go to the right, so I have no way of testing if my car dies or not.
