Fuel Starvation

[BillR1212]

Hi Team,

This is my first post on this forum. I was referred here recently. I got bored today and thought I'd take my first trip to the 1/4 mile drag strip. I was excited to finally have some worry free fun, and test out my new combination (505 stroker, 73 cuda, 500hp at tire 5500RPM) with some Nitto street drag radials to provide some traction. Sadly however my best time was 13:23 at 74 MPH as my car ran out of go juice slightly before the 1/8 mile mark and I'd end up coasting the rest of the way. Needless to say I got scared of the lean conditions and called it quits after a few tries. I guess I've never had her under load through the gears on the street as you hit 75-80 pretty quickly and get out of it before I drain the bowls.

Anyways it's a AED 950 carb feeding it, so I"m guessing I'm just running the lines dry. So my question is do they make a good sump tank to put up front to provide me with some extra fuel for short bursts, or do I need to run larger lines. I think I have 3/8 right now. Thanks in advance for the replies. I'd love to get this ironed out and back at the track, I had a blast and was beating the cars next to me for the first half of the track, would have been nice to see what the top speed was at 1/4 mile as she pulls hard on the highway when I roll into it.

[GoodysGotaCuda]

Welcome!

You shouldn't need much of a sump for that application, what type of pump setup are you running?
Do you happen to have an air fuel ratio gauge? That can tell you in a little more detail what is happening.

[Roadman]

            replys on the way.   

[BillR1212]

Hi - Thanks for the replies. I have a carter mechanical pump. Forget the number but my builder specd that out for me and said it would do the trick, I don't have a A/F gauge. It was dialed in perfectly on the dyno a few weeks ago, however I can't speak to what it was doing on the track, other than completely loosing acceleration and would come back to life after about 3-4 seconds.

[RUNCHARGER]

My first instinct would be to add an electric fuel pump at the back near the bottom of the fuel tank. A big mechanical pump should be able to feed that okay though with a 3/8" line. How is the fuel tank vented?

[BillR1212]

I can't answer that question on the vent. I'd have to look into it. Up until I bought this car a few years ago, my mechanical abilities were non existent. I'm learning as I go. I'll put the car on the lift later this week and see what the vent looks like.

[Chryco Psycho]

Tanks inc makes a good system ,3/8" with electric in tank pump  , I was able to go 12.0 with a 440 before the starvation hit using 5/16 line & electric pump  , you need 3/8" all the way back minimum , so you need 3/8 pick up tube all the way up to the carb , I would also recommend an electric pusher pump . 1/2 line would be Ok too .

[BillR1212]

Would a replacement sending unit with 3/8 line fit my stock tank? It's a 73 340 car originally. Looking at Summit - Right stuff detailing ESU 7002. I'm told my car is 5/16 line as I just had somebody double check for me.

Bill R

[anlauto]

Would a replacement sending unit with 3/8 line fit my stock tank? It's a 73 340 car originally. Looking at Summit - Right stuff detailing ESU 7002. I'm told my car is 5/16 line as I just had somebody double check for me.

Bill R

YES...it will fit no problem. However they will be no advantage if your car still has the smaller 5/16 line.

[Cuda Cody]

With a bigger line you might need to get a bigger pick up in the tank.  I bet an electric fuel pump would help.

Also, have you made sure the float levels are set right in the carb?

[Cuda Cody]

Also welcome @BillR1212   

[303 Mopar]

Welcome from CO!  If you do not have a return line I would add one, along with an electric pump. @MoparDave at Roseville has fuel sending units with a return nozzle.  One of the best pumps I have experience with is a Mallory 110 as it is one of quietest. I had this set up a the 408 stroker in my '71 Challenger, and currently have this set up on the 505 stroker in my '68 Charger.

[BillR1212]

With a bigger line you might need to get a bigger pick up in the tank.  I bet an electric fuel pump would help.

Also, have you made sure the float levels are set right in the carb?

Float levels are just a touch over the clear sight holes. It was tuned last month at the Dyno shop and dialed in perfectly with the A/F ratio. And yes the thought would be to put a bigger sending unit in. Run 3/8 lines and see if that works. If not, then a pusher pump may be the answer? Thinking of ordering the sending unit and line shortly. Will give me a project for the long weekend.

Bill R

[HP_Cuda]

The real answer here is to have the dyno guys provide you with AFR output all the way through the power band.

That will tell you if you are running into a lean condition at the top end, then you can go from there.

Here is a nice clean install of an electric with a filter.

[BillR1212]

Welcome from CO!  If you do not have a return line I would add one, along with an electric pump. @MoparDave at Roseville has fuel sending units with a return nozzle.  One of the best pumps I have experience with is a Mallory 110 as it is one of quietest. I had this set up a the 408 stroker in my '71 Challenger, and currently have this set up on the 505 stroker in my '68 Charger.

Man I was just in Denver for a week in early November. Should have reached out. I stayed downtown at the Marriott City Center. It will likely be covered in snow next time I'm back but this spring or summer I'd love to check out your ride! I go there for work quarterly.