Hi Guys,

Looking for some help with my dragster. Et and MPH has really fallen off since the beginning of the season.
We have been chasing this for a few weeks now, and the car keeps getting slower and slower and the mph keeps falling off. Obviously, something is going away but we are not sure what to check now.

At the start of the year, we switched over to methanol. We put new tires on and also put in a new Abruzzi convertor. Also brand new APD 1250 carb. At the start of the season, things were good. Car was faster than ever going 4.80's at over 140. This was in July. This past weekend in way better air the best it would run was a 4.96 and the last pass was 4.98 at 136.

Here are the things we have checked:
Changed plugs, Crank trigger pickup, Checked the grid for sufficient battery volts (17+ volts), timing retards. Checked grid for ignition in and out and overlaid them. New cap and rotor. Checked timing and rotor phasing. Checked distributor gear for wear. Checked valve lash. Checked valve spring pressure and some were weak so this past weekend was with a fresh set of springs. Tore the fuel pump apart (electric Magnafuel Prostar 500) everything looks good. Turned up the bypass pressure from 26 to 30. Checked fuel pressure at regulator. Running 8 lbs. Have tore the regulator apart. No fuel filters in the system to clog up. Have checked all the jets and air bleeds in the carb.

Here is an overlay of two runs. The blue is from earlier this season and the red is from last pass yesterday.


Here are our numbers from the start of the year.


And yesterday's numbers:


Anyone have any ideas?
Thanks in advance.

Does convertor have a sprag?

Yes I believe so. I am not 100% though to be honest.

As much high hp stuff Abruzzi has his hands on, I'm pretty sure his spragless line up is strong 1/4 mile bracket racing.

It has a bad fuel line/fitting on it. Which one? I have no idea.

I've seen people spend a lot $$$ chasing it, even seen em buy engines with the problem following.

Bad fuel line/fitting.

I can see it being fuel related too. But if your dragster shakes the tires in the burnout and it has a sprag it will kill a convertor.

quote:

Originally posted by ts393c:
I can see it being fuel related too. But if your dragster shakes the tires in the burnout and it has a sprag it will kill a convertor.

True!

The engine is skipping like it's running out of fuel correct Corey?

I will say 8 pounds of pressure is a lot. Every time I ran that much it would blow the bowls over.

quote:

Originally posted by Mike Rietow:
As much high hp stuff Abruzzi has his hands on, I'm pretty sure his spragless line up is strong 1/4 mile bracket racing.

It has a bad fuel line/fitting on it. Which one? I have no idea.

I've seen people spend a lot $$$ chasing it, even seen em buy engines with the problem following.

Bad fuel line/fitting.

The two lines from the regulator to the carb are older. Everything else is less than 2 years old.

Here is a video from a few weeks ago.

https://youtu.be/nAjTSY5wAR4

This is before we put new springs on it. There are several runs there. the big thing to watch is the tach of course. The fuel pressure gauge is in the bottom right corner.

On the tire shake in the burnout, my driver says it doesn't shake in the burnout. for what it's worth it is a diamond, dual suspended car and we are running little bubbas on bead locks.

quote:

Originally posted by CHampshire:

quote:

Originally posted by Mike Rietow:
As much high hp stuff Abruzzi has his hands on, I'm pretty sure his spragless line up is strong 1/4 mile bracket racing.

It has a bad fuel line/fitting on it. Which one? I have no idea.

I've seen people spend a lot $$$ chasing it, even seen em buy engines with the problem following.

Bad fuel line/fitting.

The two lines from the regulator to the carb are older. Everything else is less than 2 years old.

We had a guy local skipping down the track for six months always asking for time runs in between rounds trying to fix the thing, nice car Chevy II. We hear him come down the track engine skipping and a buddy says damn it ain't fixed! They just bought a new engine. I said WHAT! He said yeah.

So I walked over there and said you got a bad fuel line. He looked at me funny. He said which one, I said I dunno and pointed at the first one I saw. I told him put new fittings too. He went and bought a line at the track and two fittings.... Fixed!

They won the footbrake World finals with it a few months later.

True story. I got lucky on the fuel line I pointed at.

You got a bad fuel line Corey. I have no clue which one.

quote:

Originally posted by ts393c:
I will say 8 pounds of pressure is a lot. Every time I ran that much it would blow the bowls over.

How much do you run on alky with an electric pump?

Mike,

It is possible. There are two lines we migrated over from the Nova. Not opposed to swapping them out for new. Also, I just checked Abruzzi's site. He does build them with or without sprags

I don't think its converter related. My guess is fuel also. Have you checked your floats? Alky is not kind to them. Brass floats can collapse and the black ones can become alky soaked messing with the fuel level in the bowls, check those. If you have O2 logged you know right away if it was fuel related.

Also have you noticed it using more fuel on a run now vs at the start of this swap, this would be another indication you got float bowl issues. Alky can run fine even when it's pig rich unlike gas...

quote:

Originally posted by CHampshire:
Mike,

It is possible. There are two lines we migrated over from the Nova. Not opposed to swapping them out for new. Also, I just checked Abruzzi's site. He does build them with or without sprags

Call him. The engine is down 75hp (fuel probably), where the stator would active if a one way clutch is in play, the engine looks to be skipping not accelerating. You definitely wanna know what you have, if not for this go around, for future. Lets hope its a spragless to rule out that variable, and you get lucky with it needing just a fuel line.

Call him

quote:

Originally posted by TOP38:
I don't think its converter related. My guess is fuel also. Have you checked your floats? Alky is not kind to them. Brass floats can collapse and the black ones can become alky soaked messing with the fuel level in the bowls, check those. If you have O2 logged you know right away if it was fuel related.

Also have you noticed it using more fuel on a run now vs at the start of this swap, this would be another indication you got float bowl issues. Alky can run fine even when it's pig rich unlike gas...

No o2 unfortunately. Thanks for the info on the floats. They are the black ones. They were new with the carb and have 50 passes on them. As far as fuel useage, we used 5 gallons yesterday on two warm ups, two time runs and first round. That doesn't seem like a lot to me, but I am new to alky so I don't know for sure. It's a lot compared to race gas though!

quote:

Originally posted by Mike Rietow:

Call him. The engine is down 75hp (fuel probably), where the stator would active if a one way clutch is in play, the engine looks to be skipping not accelerating. You definitely wanna know what you have, if not for this go around, for future. Lets hope its a spragless to rule out that variable, and you get lucky with it needing just a fuel line.

Call him

We will check with Abruzzi and see what we got for sure.

Picture of the fuel system:

I watched video and can hear what I believe is the issue/loss. As soon as it leaves and goes against convertor it bogs down a couple hundred rpm then starts accelerating. Both passes and faintly after the shift. I would call APD and Abbruzi and let them watch it. one of them can help you find it. Good luck.

quote:

Originally posted by CHampshire:

quote:

Originally posted by TOP38:
I don't think its converter related. My guess is fuel also. Have you checked your floats? Alky is not kind to them. Brass floats can collapse and the black ones can become alky soaked messing with the fuel level in the bowls, check those. If you have O2 logged you know right away if it was fuel related.

Also have you noticed it using more fuel on a run now vs at the start of this swap, this would be another indication you got float bowl issues. Alky can run fine even when it's pig rich unlike gas...

No o2 unfortunately. Thanks for the info on the floats. They are the black ones. They were new with the carb and have 50 passes on them. As far as fuel useage, we used 5 gallons yesterday on two warm ups, two time runs and first round. That doesn't seem like a lot to me, but I am new to alky so I don't know for sure. It's a lot compared to race gas though!

My sb uses very little fuel to warm, i can drive it to the lanes to warm it enough.

My BBC's I'd turn the four mixture screws in all the way in to warm it (winter) and leave the lean out valve open, It would use half the fuel. Turn em back to a turn and half out, and drive to the lanes.