Need some carb help
Login  | |
|
Need some carb help - 3/27/2008 3:45:25 PM
|
|
|
Sweetness224
Posts: 35
Joined: 12/4/2007
Status: online
|
So my 81 vette has a crate 350 in it with a 800cfm carb (previous owner had the work done). Well i noticed it had a bog (almost like it was flooding out the engine) in it when you gave it an instant full throttle and i noticed the exhaust from the car had some black in it so it was running really rich. I took it in and had it tuned up and it runs a lot better now but there still is a bog at low rpms when you give it an instant full throttle. I was reading on car craft saying that a good size for a carb on a 350 would be 600-650 cfm or there are adjustments i could do to my current car like rejeting and so forth. I don't know a whole lot about carbs so any info on that would be very helpful and also if there is something else that im over looking that could be a causing this problem. There is about 2000 miles on the new engine so i didnt have any idea what it could be besides an oversized carb. What do you guys think? Also im looking at putting new weatherstripping on the car and was wondering if there is any tips or anything i should be aware of that might make my experience with this a little easier with less headaces. And one last thing... My antenna is stuck up and how do i go about getting it to go down. Would pulling the motor off and sliding it down manually work? It doesnt really matter to me to have it to pick stations up at the time. I'm going to be working on a sound sytem at a later time and will deal with getting it to work properly then. I just want to get it down so i can get a car coverly completely on it and so i dont get some idiot riping it off in the parking lot. Thanks ahead of time for all of your help!
Blake
_____________________________
When you turn you car on, does it return the favor?
|
|
|
|
|
|
|
RE: Need some carb help - 3/27/2008 4:47:38 PM
|
|
|
DeeVeeEight
Posts: 517
Joined: 10/24/2007
From: South Jersey
Status: offline
|
I am not a carb expert either but it sounds like you are having a problem with the accellerator pump. My Holley 750 had a flat spot when I got on it and my mechanic ended up reworking the accellerator pump, he actually wanted it to deliver more fuel on acceleration.
Can't help you with the antenna or the weatherstripping.
_____________________________
If you don't ask, you get the same answer as no.
1979 L-82, 383 Stroker, Edelbrock RPM Air Gap intake, Holley 750, Headers, Flowmasters, VB&P 400# rear monospring, Richmond 5 speed. American Racing Vector Wheels, Firestone Indy 500's
|
|
|
|
|
RE: Need some carb help - 3/27/2008 5:07:13 PM
|
|
|
Sweetness224
Posts: 35
Joined: 12/4/2007
Status: online
|
sounds like good stuff. How do i go about checking the accelerater pump?
_____________________________
When you turn you car on, does it return the favor?
|
|
|
|
|
RE: Need some carb help - 3/27/2008 5:38:38 PM
|
|
|
78buckshot
Posts: 671
Joined: 1/28/2007
From: Michigan
Status: offline
|
Hi Sweetness224, the 800 CFM carb is more than the engine can use, 600 - 650 would be much better suited to the 350. Depending on the brand of the carburetor - Holly, Edelbrock, Rochester, some fine tuning may get you to a more decent running package. The accelerator pump is one area of the carb that can be tuned. Also the type of secondary throttle actuation (mechanical vs. vacuum) is a key component to drivability. Try to figure out what brand and type of carb you now have and get back with us. Many times in an attempt to produce more H.P., people will "over-carb" the engine, that is what your dealing with at this point. I'd think about a new carb. better sized to the 350.
|
|
|
|
|
RE: Need some carb help - 3/27/2008 7:00:59 PM
|
|
|
C3 Starship
Posts: 4814
Joined: 7/25/2006
Status: offline
|
In my experiance, the carb tune and timing are crucial to smooth acceleration. And yes, I agree, sounds like your engine is over carbed.
My 454 only calls for a 650 to 750 cfm. I could go to an 850, but then I'd just be wastin' gas.
_____________________________
1980 L-82 Fastback (forward too)
Mono composite front and rear.
Full adjust ride height and
response.
400+ hp, 454, M-22, 3.07
2007 H. D. Sportster, XL 883 EFI
http://i121.photobucket.com/albums/o225/C3Starship/HPIM0423.jpg
|
|
|
|
|
RE: Need some carb help - 3/27/2008 7:30:02 PM
|
|
|
Sweetness224
Posts: 35
Joined: 12/4/2007
Status: online
|
Im away at school atm and my baby is back home in the garage but i 85 percent sure its an edelbrock. After your guys info i do think its over carb, anyone got a good suggestions on some good carbs to but on it, im roughly at 350-400 hp right now. I want something that would be good for drivability too but yet good power.
_____________________________
When you turn you car on, does it return the favor?
|
|
|
|
|
Printable Version
Of course that assumes you have a stock type manifold for spread-bore type carbs.
