vvv90

I think it's poor, but maybe it's normal. :leaving:

O.k. When I drop it into 1st or 2nd from a roll, it pulls pretty decent at mid to high RPM's....very impressed.

However, off the line at low RPM's when I punch it.....Or if I just punch it in a high gear without downshifting and I am in lower RPM's (<2k) under load it feels like it has no torque. Maybe it's just a low rear end gear but....

....I can smell the exhaust and it smells very rich.

Therefore, I'm thinking it's something to do with the carb and timing. Is there anything that I can check?

From what I understand about carbs, is that the power valve is held closed during vacuum, or at idle/cruise. But when you punch it under load, vacuum drops to near 14.7psi or atmospheric and the power valve opens allowing a richer mixture to enter the manifold.

:confused: If I'm running rich, I guess fuel isn't my problem, but probably proper timing advance.

I'm so confused :confused

Anyone? anyone?

Brettmc

Dunno man, but I'll boot you ttt.

Brett :thumbs:

lars

You need to start by getting your timing set up. "90% of all carb problems are timing problems..." Make sure you're getting 36 degrees total advance and that this is all slamming in by 2500 rpm. Make sure your vacuum advance system is hooked up and operational.

Since you're referring to the Power Valve, I assume you're running a Holley or BG carb. Q-Jets don't have power valves, but rather a power piston that holds the primary rods in the main metering jets. Once timing is set up, you can certainly do a little tuning and tweaking on the carb - I have a how-to paper covering Holley and BG carbs that I will gladly send you if you drop me an e-mail request to:
V8FastCars@msn.com.
I can also send you info on setting up that timing if you're unsure of the technique for doing the total timing.


[Modified by lars, 3:48 PM 4/5/2004]

vvv90

Cool Thanks. :seeya: I'll be sending you an email, I really need to understand how to set timing on this car. I really think it's my problem.

Well, I have Doug Roe's book on Q-jets (which is what I have. Pretty sure it's stock too) and he defines it as a "Power-valve" But essentially you are right from what I can understand from this book. I have to re-read it a couple times before it sinks in.

Fevre

Lars has several good papers in the tech tip section under the tool bar at the top of the screen menu.

73 LS-4

Lars is right, check your timing. The stock advance curve is absolutely terrible, Mine really woke up with a more aggresive advance curve. Of course gearing has something to do with it as well, what gears are you running and which 4 spd?

:cheers:
Pat Kunz

vvv90

I have no idea what the gearing is, but I have a TH400....3spd :sad: