| Author |
Message |
Nigel Cheveralls (308gt4uk)
New member
Username: 308gt4uk
Post Number: 2
Registered: 4-2002
| | Posted on Monday, April 15, 2002 - 2:27 pm: | |
Thanks all for your thoughts. I will report back once I have tried some of your suggestions. It does indeed happen on both l and r hand corners and at quite modest speeds at times. No shortage of fuel in tanks. I like the sound of the pump/filter combination since I don't think either would cause such an immediate and pronounced effect on their own. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 153
Registered: 5-2001
| | Posted on Sunday, April 14, 2002 - 8:22 am: | |
That's correct Richard. A DCNF, fitted to a 308, feeds adjacent cylinders on the same bank. |
Richard Stephens (Dino2400)
Junior Member
Username: Dino2400
Post Number: 58
Registered: 10-2001
| | Posted on Sunday, April 14, 2002 - 12:29 am: | |
Bill informed:
"The float bowls on DCNF carbs, as fitted to the 308 series, are on the side of carb facing the front of the car. Idle mixture adjustment screws are on the opposite side of the carb, facing the rear of the car."
Thanks Bill. So I assume that instead of each barrell of a carb feeding a cylinder on opposite sides of the V (a la dino206/246), that they instead feed adjacent cylinders on the same side of the V? I'm curious as to what the intake manifold(s) look like - couldn't find a photo on the web anywhere of a 308gt4 engine bay. Anyone have a photo handy? Thanks again for clarifying! |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2395
Registered: 2-2001
| | Posted on Saturday, April 13, 2002 - 10:51 pm: | |
Bill as I said I had a 1/4 of a tank of fuel left. This curve was a bear and had long radius to it. The bank was steep so it was under the best, or worst conditions to cause any fuel starvation. For the low fuel light to come on with a 1/4 of a tank of fuel left there had to be severe force pulling the fuel away from the pickup. This car has always held its own in taking curves but this is the Grandaddy of all curves and at 80 mph she was put to the test. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 150
Registered: 5-2001
| | Posted on Saturday, April 13, 2002 - 10:52 am: | |
Magoo,
Looks like nailed that one. Good info. I wonder how low the tanks need to get before this problem rears its ugly head? |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2391
Registered: 2-2001
| | Posted on Saturday, April 13, 2002 - 9:54 am: | |
Bill, Sorry I did the other day and no problem. Sorry I didn't say that. |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1046
Registered: 2-2001
| | Posted on Saturday, April 13, 2002 - 5:52 am: | |
I ran my car low on fuel a while back and parked it in front of my house on the street which leans to the right and when I went back to it, it would not start as the fuel ran to the right side tank starving the fuel pump. Had to go get my lawnmower fuel and add enough to fire it off. Another lesson learned. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 147
Registered: 5-2001
| | Posted on Saturday, April 13, 2002 - 1:01 am: | |
Magoo,
To test this hypothesis, why not try this same run with full tanks? |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2387
Registered: 2-2001
| | Posted on Friday, April 12, 2002 - 11:44 pm: | |
P.S. The float level ultimately caused the falter because of lack of fuel but the pump couldn't supply enough fuel to the float bowl on a low tank in a severe bank. |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2386
Registered: 2-2001
| | Posted on Friday, April 12, 2002 - 11:41 pm: | |
There is a great section of road here in Florida that goes to a private airport. It is about 5 miles long. It appears that when they designed it they had Ferraris in mind. Beautiful hairpin curves and straight aways 1/4 to 1/2 mile long. Very low traffic and NOOOOOO Cops. Anyway the other day I loaded my 308 into a hairpin curve at 80 mph, and I noticed the engine was faltering slightly. Then I looked down and the red warning light for the "low fuel" came on, even though I had a 1/4 of a tank of fuel left. I think under severe leaning of the car in hairpin turns the low fuel moves in the tank away from the pick up and causes a loss of fuel to the carbs. This only happened once to me under severe conditions. I'm sure it wasn't float level. |
David Prall (Davidpra)
Junior Member
Username: Davidpra
Post Number: 87
Registered: 2-2001
| | Posted on Friday, April 12, 2002 - 5:38 pm: | |
Doesn't really matter... When a car is being driven hard (even street use), mechanical components (the engine and the attached carbs, for example) are subjected to a loads environment (G-forces, in this case) which is directionally random. True, there is some directional biasing, but a carb will be shaken in every 3D direction at some point.
Therefore, it is not possible to completely prevent fuel starvation by simply re-orienting the float bowl. This is, of course, a major reason why race cars went to FI as soon as it was practical. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 145
Registered: 5-2001
| | Posted on Friday, April 12, 2002 - 4:33 pm: | |
The float bowls on DCNF carbs, as fitted to the 308 series, are on the side of carb facing the front of the car. Idle mixture adjustment screws are on the opposite side of the carb, facing the rear of the car. |
Richard Stephens (Dino2400)
Junior Member
Username: Dino2400
Post Number: 57
Registered: 10-2001
| | Posted on Friday, April 12, 2002 - 3:51 pm: | |
What carbs are on the "UK spec 308 gt4"? Are they DCNF? If not, never mind what I'm about to say. But if they are DCNF, here's a thought: with the engine being a V and mounted transversly, the float bowls are facing to the side, right? When you corner, the fuel can run up the walls of the float bowl and away from the outlet on the bottom of the bowl.
DCNF carbs don't exhibit this problem in applications where the floats are facing forwards, such as V6 dino engine on front-engined Fiat Dinos, or transverse inline engines (x1/9, 128, Yugo) but have exhibited power loss during cornering in applications where the float bowls are to the side (124 spider for example). |
bruce wellington (Bws88tr)
New member
Username: Bws88tr
Post Number: 44
Registered: 4-2002
| | Posted on Friday, April 12, 2002 - 1:41 pm: | |
nigel
check the float...in my tr same problem, also check fuel filter... |
Greg Rodgers (Joechristmas)
Junior Member
Username: Joechristmas
Post Number: 219
Registered: 3-2001
| | Posted on Friday, April 12, 2002 - 1:26 pm: | |
Yeah, I think it is the nature of the beast. I set the floats higher and it helped but I am afraid I will not be able to get them high enough to get out. |
Edward Gault (Irfgt)
Intermediate Member
Username: Irfgt
Post Number: 1031
Registered: 2-2001
| | Posted on Friday, April 12, 2002 - 12:43 pm: | |
Greg, this is probably what you are experiencing going up your driveway. I suggest you move to a new house. |
David Prall (Davidpra)
Junior Member
Username: Davidpra
Post Number: 86
Registered: 2-2001
| | Posted on Friday, April 12, 2002 - 10:45 am: | |
Fuel starving while hard cornering is weak point with the carbed 308's. I don't know of a good solution. I've seen guys experiment with alot of things such as float shapes, float heights, and bowl baffles and get mixed results. I would recommend talking with someone who races (any car) with Weber setups, or try Weber themselves to see if they have suggestions or performance kits available.
Or trade your car for an injected model. |
Bill Sebestyen (Bill308)
Junior Member
Username: Bill308
Post Number: 135
Registered: 5-2001
| | Posted on Saturday, April 06, 2002 - 4:28 pm: | |
Nigel,
Does it loose power on both left and right hand corners?
Bill |
magoo (Magoo)
Intermediate Member
Username: Magoo
Post Number: 2267
Registered: 2-2001
| | Posted on Saturday, April 06, 2002 - 3:53 pm: | |
Greg you are right but Nigel also check to see if your fuel filter may be getting clogged. Make sure the fuel pump is putting out what it should and not binding. If this just happened and the car has been running ok I don't think it is your float levels. Just a thought. |
Greg Rodgers (Joechristmas)
Junior Member
Username: Joechristmas
Post Number: 189
Registered: 3-2001
| | Posted on Saturday, April 06, 2002 - 2:48 pm: | |
Check the float settings first. |
Nigel Cheveralls (308gt4uk)
New member
Username: 308gt4uk
Post Number: 1
Registered: 4-2002
| | Posted on Saturday, April 06, 2002 - 2:46 pm: | |
I have a '77 UK spec 308 gt4. It runs well, but losses power on cornering of any significance. Feels rather like fuel starvation, but could equally be flooding. Can anyone suggest some simple tests to identify the cause before removal and rebuild of carbs is undertaken? |