Here is my latest run with the Coronet

13.035 @ 104.08 MPH 60 foot 1.905

Listen to the run, it sounds like it bogs or hesitates off the line.

I launched at 2000 rpm's car was warm, 200 or so.

I was a little bit disappointed in my MPH, it actually came down from 106 to 104.08.


MIke

Don't 4 get it's hot out there and put a little more fuel out the squirters will get rid of the flat spot

Vary your launch RPM any?

Should be in the mid 1.7's for 60's

200 is really hot... Try it at 160 to see what it does.

Like mentioned time for squirter and cam adjustments.

what's the build? I ran 12.90 in a 67 'net at 104. But my 60 foot was 1.68-1.70. 200 is a tad hot for me. how do you launch the thing? what carb?

Doesn't sound like it spun like you'd mentioned in the pm.... Does sound like a bog.......needs more fuel...... more squirter......

Thanks guys! You know when I launched it felt like it spun, so I'm wondering when you jump up squirters is it similar to jetting up?

Mike

What carb are you running.

I am still running a 770 street avenger, but got a really good deal on a 870 street avenger, but I haven't had a chance to go through it yet.

Mike

You'll need a spring kit at a minimum and possibly a 50cc pump/squirters to get that bog spot out of it.

Might have to stretch the squirt out to cover when the secondaries start to open.

If you have an AF meter that records you would likely see it go real lean when 5-20 feet out.

If you spend money on a different carb, buy a double pumper!

I have a auxiliary electric fan mounted to the front of the radiator. I use a manual switch to keep the temperature right around 140 degrees when I race. To me, 200 is way too hot for making maximum power.

I assume the street avenger is a holley? You should put jet extensions on the rear jets just to make sure that is not the issue. With out them, the rear jets can come uncovered on the launch . May require a different float. Also, get that temp down! Leave at 135 to 140 if you can get it down to that for the next run for tuning simplicity. You may need more fuel all around, squirters, jets, etc. Jet for mph, squirters for 60 ft.
Do you have a cold air kit? A well sealed aircleaner base with good airflow, like a Moroso dropped air cleaner base?

As said above...get the temp down. If you are launching @200, you are most likely boiling water at some point during the run.

Up the squirters to get rid of the bog, then jet for mph, then go back and see if you can get by w/any less squirter. There used to be good reading on the Holley web site on tuning carbs.

Might want to check timing; that can make it run hot. Good Luck

I listened to your clip. The car is not bogging at the hit it's bogging a few feet out which would indicate that it's running out of pump shot.You can correct this with a smaller squirter or a pump cam with a longer duration. Also check the float level's you may want to raise the rear float a little higher than normal and or add float extensions. If you haven't done so already put some lighter springs in the distributor to get your advance in quicker. And 200 is way to hot you should try to go into the water no hotter than 160. Good luck I hope this helps.

Thanks for the help guys. The carb info is really helpful. I'll work on getting the temp down. I got an electric fan on it and don't think it's hold well enough.

Mike

Looser 10" convereter would be by call. Try the carb thing and if it doesn't do much, I'd get a converter. That was the biggest improvement I made when I had a heavy car.

Nice 69 Super Bee!!

Sounds like your due for a new radiator and some water wetter. Your car will run 12.90-12.70 with a 1.80 sixty at 104mph. What converter do you have?

I would personally ditch the vacuum secondary carburetor and put a 750dp on. I don't think more carb would help much either and would soften the throttle response.

What, if anything, did you change from last fall?

The hesitation is from a lean condition, and it happens 20 to 25 ft out. So, it could be the squirter duration may needs to be lengthened. Or it could be that the vacuum secondaries are starting in a bit too early. If tuning the squirter does not help, try a slightly stiffer secondary vacuum spring. These are all simple things that you should do at the track to get it right.

I think it is always a good idea to understand changes in the mph. The atmospheric conditions from last fall to this spring could be the answer. If that is the reason, simply waiting for the same weather conditions as last fall alone will put you into the 12s. Your 60 ft this spring must be a little better than it was last fall as the ets are about the same but with 2 less mph.

To really fine tune for performance, you need to acquire a weather station so that you can truely compare run to run changes. You can buy an inexpensive weather station and collect the temp, pressure, humidity (or water vapor pressure), and get the formula on line to determine the DA for each run. It won't be real time for tuning at the track, but you can compare the results when you get home.

Make sure that you find the very best shift point rpm for each gear. My cars have been pretty sensitive in both et and mph on shift point. Most important, where ever you choose to shift, be consistant.