Got a 14.54, its getting better..... but

Got to the track today, beautiful weather, pretty busy.
First pass. got a 14.54 @ 95.23 mph 60' was a 2.21 Did a small burn out to clean the MT DR's, it was pushing the front tires for the most part, no John Force burn out here, LOL
Brought rpm to 2000 against the brake, last yellow goes out and Im off, decent clean run, I let it shift buy itself 1 to 2 @ 52/5300 rpm then hit 3rd manually @ 5500, seems to do good that way.
Second pass, no burn out, figured why bother, bring rpm up to 2500, last yellow goes out, and Im off again, spun a bit leaving, Im shifting manually this time @ 6000, YEAH RIGHT, it noses over BAD at about 5400 rpm, like the fuel was shut off, I back off the gas, it recovers then goes, well, that sucked, 16.46 @79.08 mph
Third and final pass for the day, Im letting it auto shift 1 to 2 @ 5300 rpm, leaving the line @ 2000, trying to duplicate my first pass, leaves with some tire spin, approaches 5300 rpm and the fuel goes away again then recovers, 15.89 @ 86.68 mph
Im thinking my fuel issue has to do with the rubber sections on the steel line are collapsing when the pump really starts sucking around 5200 rpm.
It cruises fine on the highway @ 3000 rpm.
Cool, more tinkering:Brow:

 

Do you have a plugged fuel tank vent? After each pass open gas cap to release vacuum. Its a nice day get back there. Remember anticipate the green don't react to it.

 

I had thought of that but it ran fine the hour ride home @ 3000 rpm.
Cant have it misbehaving at BPG!
I was trying to get some consistency but the car wasn't having any part of it, LOL

 

Pump pushes the same psi at 800 rpm and at 5500 rpm. It won't suck closed your rubber hoses unless you used cheap hose and that is not possible when buying gas line hose. Old gas lines are hard as a rock and can't suck closed.

Your return line could be the problem if it is plugged up. I used an air compressor and pushed air through the lines back to the tank to make sure mine were not plugged up. Did the two that were plugged to the fuel pump. Take tank cap off and do it gently and you will hear the air going in the tank. You have to push the gas back to the tank so you have to just push a small bit of air in the line until the gas clears out then you can push harder on the air pusher. It worked for me never had that problem again.

Are your vent tubes plugged up or are the lines still attached?

Remember the vapor canister that used to be in the fender well? that had a return air line to the tank is this plugged or open. if it is open you will get air to the tank. The sock in the tank could be plugged up has all of this been rebuilt?

It sounds like you are running out of gas at the top end. The float in the carb might be too low, you could fix that with the Holley.

By the way, you did a 2.21 with the Q-Jet on the 60 ft. Didn't you do the same 60 ft with the Holley. I still think you will run faster with the Holley. If you have a float problem with the Q-Jet how are you going to fix it?

It does not look like the carb did much for your combination. You only gained 3 tenths and 4 mph, the tires helped by not spinning.

Why don't you repost your combination and lets see how we can make it work better, What kind of pistons do you have.

You should be able to run that motor to 6 grand each and every time with that cam, at least 5800 anyway. The engine is just turning on the hp at 5200 rpm that is where the HP and the TQ cross at.

You did not have the nose over problem when you went to the track the first time and you ran it to 6 grand then so I would think that your valve springs are ok.

So now this leads me to believe you now are having a fuel problem at the top end. Now you could have gotten something in the fuel line when you put the carb on and some dirt could have entered the needle and seat area which will stop the fuel flow especially at the top end, again this is where the Holley is just so much easier to work on, a ten minute fix and you are running again.

If the 60 fts were the same with the two carbs then the seat of the pants was the same. What does the 330 mark say for the two carb runs.

I know we could have tweaked that secondary to come on faster in the Holley, I would have to look up my notes.

At the track the tip of the day is you mash the gas when you see the last yellow bulb light up on the tree when they come down. Tip number two, When you stage and you light up the first set of stage bulbs, you move up very slowly and as soon as that second set of stage lights turn on stop right there, this will get you your best et.

 

2014 (Holley BFG street radials) 2015 (Q-Jet with MT DR's)
Reaction .4474.......................... .4334
60' 2.190......................... 2.2174
330' 6.2832........................ 6.2016
1/8 ET 9.6360........................ 9.4134
1/8 MPH 73.67.......................... 76.82
1000' ET 12.4739...................... no data
1/4 ET 14.8881...................... 14.5413
1/4 MPH 91.42......................... 95.23

X2 on running it up to 6000 rpm, it used to do that with ease, and beyond

 

Low float level or a low flow needle and seat was installed.

 

Mark; those soft compound tires probably made your improvements. With that 413 cam you may need to dial that qjet a bit more, or like Guy said, a dbl. pumper Holley, which are easily adjusted. Jerrold (jstaged) runs a Holley, jets it 78/88, with a 310 cam. FEED that engine some fuel!

 

How old is fuel pump? Could it be abit weak? You could plug the return line and see if it helps maintain pressure.

 

Raise that float up to 9/32".

 

Im going to check where its set at.
Gotta admit, this is a real learning curve for sure, but its fun and interesting:TU:

 

Wow, I don't even remember when I put that pump on there, maybe 1990/'91ou:

 

Inlet size on the needle seat?

 

If the car ran ok at 6000 before ,then you need to look at whats changed?
You realize a Qjet has 1 fuel bowl as opposed to two bowls on a Holley. Thats most likley the reason why the car never exibited these same symtoms when you had the Holley on there!
You need more fuel system now to keep up WOT demand. Qjets like low psi with hi volume ,and most pumps arent made this way.
Fuel delivery is paramount anytime you run a Qjet and this is a prime example of that.
But hey,all the folks on this web site who swear by the QJet carb for a Buick should know this:TU:

And i agree with Guy, the car ran better due to tires,carb so far is a wash.
Also the sixty foot times are still vey poor,indicating tires still spinning or a very badly designed converter

 

does it run out of fuel at the top of 3rd gear?

Or does it have trouble in any gear including 1st gear at 5000+rpm?

 

How much fuel in the tank? If it was less than half that could be a problem since it seems to have gotten worse every run. Some of this was mentioned earlier: checking the float level plus check the needle and seat diameter. You need the bigger one on there. Check the return line. Check the fuel pickup sock. A fuel pressure gauge tapped in right at the carb and run to the hood so you can see it when you go WOT would help.

A few thoughts. I would say you picked up a some nice HP because you picked up 4 mph which has nothing to do with tire spin and since your 60' was about the same but you picked .3 sec then that was made by more power through the gears, not less tire spin off the line. That being said then either you are spinning just about the same as you were before which should be all but impossible with correctly used Drag Radials compared to regular tires or you really weren't spinning that much in the first place.

You need to clean the Drag Radials before you get to the line no matter what is going on. With their stickiness you pick up all kind of trash just getting to the line plus you don't know what kind of moisture on the ground you have driven through. You don't have to do a big burnout. Any spin matters so if you are power braking to 2000 and it spins even the slightest back off 200 rpm and see if it holds. As others have mentioned. Sometimes flashing from 12-1500 just off idle may work better than power braking.

As far as off the line goes I shudder to think about a 413 cam in a 350 coming off the line without a 3500 stall converter and some good gears no matter how much "torque" a 350 makes.

One last comment and this doesn't just include Mark. Too many people are guilty of doing this. If you are going to start a new thread with every new development please include links to past threads that have pertinent information or just continue an old thread so that the same information or suggestions are not brought up again. Just sayin'.

 

Before you get into a rut chasing fuel issues, have you thought about ignition or valve float? I've had both do just what you're describing.

With my ignition, I wasn't running a full 12v to a pertronix unit and it would run fine, right up to redline where it would nose right over.

With the valvetrain, I ran slightly heavier rockers and it was too much for my stock springs over 5k. Again, nosed right over.

And I initially blamed my trusty Q-Jet for both.

 

Was thinking exactly the same thing

 

Hey Ken, Sorry my inbox was full, I emptied it.
The second and third run is when it started doing this.
Beginning of second run: put trans in 1st, I was going to try shifting at 6000, I take off, pulling like mad, then the anchor came out, I back off the throttle, put it in second, it recovers and goes in second, seems ok again till I shift to third at 5000, and finish the run.
Third run: figure let it auto shift 1 to 2, hold second to 5500, see what happens, always seemed to do good that way, start, revs climb to 52/5300 where it shifts, and whaw, anchor comes out again, WTH, back off the throttle, it recovers, and I finish the run.
All the running around getting on it with the Q-Jet around town, never had an issue, the carb performed flawlessly, the only adjustment I had to make was tweaking the secondary air doors a tad tighter on the spring to eliminate the bog.

 

Im looking into another convertor, the TCI unit (street brawler, I think) I bought from Summit about 20 years ago. Im sure it was fine with my old Kenne-Bell Mark 2 cam but its out of its league with the 413 cam
I noticed on my first run it seemed that the engine did labor a bit till the revs came up, its weird why I noticed that.
My tank was over half full on the second and third runs. Im still going to check the rubber sections of fuel line connecting the factory steel lines together. Then my float level, then needle and seat size.
Sorry for starting another post, Im sometimes over anxious to post stuff and don't take the time to look for my older related posts