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Fuel Starvation

Started by BillR1212, November 19, 2017, 03:57:16 PM

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BillR1212

Quote from: HP_Cuda on November 20, 2017, 10:50:42 AM
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.

I have those notes. the AF seemed dialed in from 2000 - 5800. I believe the float bowls are just running dry during the run. It's been mint so far up until the drag strip where I'm WOT from the get go. Currently I can do a hard pull on the highway just fine. Granted I'm sure if I stayed in it to 120 plus it would eventually drain, but I never go that fast on public roads, so after 3-4 seconds I let off. That is a nice install!

HP_Cuda


Can you post the AFR data here from 2000-5800?
1970 Cuda Yellow 440 4 speed (Sold)
1970 Cuda clone 440 4 speed FJ5
1975 Dodge Power Wagon W200

Brads70

Quote from: BillR1212 on November 20, 2017, 10:33:24 AM
Quote from: Cuda Cody on November 20, 2017, 09:16:29 AM
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.
Maybe try raising it to half on the sight glass?
Also perhaps jet extensions in the rear would help? My quickfuel came with them.


BillR1212

I just pulled out one of the data sheets. I need to figure out how to post them now since photo bucket is gone. Looks like I'm at 12.8 AF through the pull. I'll mess with posting it later after work.

Chryco Psycho

on the glass floats you should be 1/2 way up

HP_Cuda


If you have it in jpeg format you can just go below and use the attach feature.

Look forward to it.
1970 Cuda Yellow 440 4 speed (Sold)
1970 Cuda clone 440 4 speed FJ5
1975 Dodge Power Wagon W200

Shane Kelley

For myself I'm not really a electric fuel pump kind of guy. I don't like hearing them and if you mount it higher that the fuel level they will drain down over the winter, dry out and possibly seize up. I have had that happen a couple times in the past. I do like the Mallory pump 303 Mopar recommended. Then you could go CP route and do a tank with internal pump. That would eliminate the noise and drying out issue related to external pumps.

I really think going with the 3/8 pick up and 3/8 fuel line all the way to the carb would be adequate to run in the 10's. You didn't mention what your running for a fuel filter. Those can really hurt the flow especially if it's dirty or poor quality. 

Fuel level should be right in the middle of the sight glass.


BillR1212

3/8th s line worked did some 1/4 mile pulls on Sunday.

My Best 1/4 is typed below

60ft - 1.965
1/8 - 7.590    /   95.55MPH
1/4 - 11.732 /  114.36MPH

Traction was tough. Had lots of tire slip and felt I had to roll into it until 3500/4000 RPMs before I could floor it. Was shifting around 5900 RPMs. 3 speed/3.23 gears. Running Nitto street slicks. Admittedly this was my second time out so I may not have heated them correctly. I have regular shocks in the rear. and QA1s single adjustable up front which I set to their lowest setting. 17PSI in my rear tires.

I think I have a lot of upside if I can improve my 60ft. Everything I read says that a 11.7 pull should 60ft around 1.55/1.6. So I think I can hit low 11.s with some practice. What a blast, I can't wait for spring time to go again. My top trap speed on the day was 117MPH on a 12.1 run. Let me know what you think and any suggestions.

Also - I get my insurance through Hagerty. Does their normal classic car insurance cover any track incidents. I thought about that driving home that I should likely call them and check before I go next time.

Chryco Psycho

I used a floating ladderbar system , was running 1.41 60' times with the same ET around 11.7 @ 118 MPH  so getting 60' faster will definatly help the ET & MPH 

Dakota

I'd check your policy with Hagerty to be sure, but I don't think they'll cover anything that happens at the race track.

GoodysGotaCuda

Quote from: BillR1212 on December 20, 2017, 12:19:17 PM

Also - I get my insurance through Hagerty. Does their normal classic car insurance cover any track incidents. I thought about that driving home that I should likely call them and check before I go next time.

Nope. You're on your own.



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1972 Barracuda - 5.7L Hemi/T56 Magnum
2020 RAM 1500 - 5.7L

My Wheel and Tire Specs


Shane Kelley

Quote from: BillR1212 on December 20, 2017, 12:19:17 PM
3/8th s line worked did some 1/4 mile pulls on Sunday.

My Best 1/4 is typed below

60ft - 1.965
1/8 - 7.590    /   95.55MPH
1/4 - 11.732 /  114.36MPH

Traction was tough. Had lots of tire slip and felt I had to roll into it until 3500/4000 RPMs before I could floor it. Was shifting around 5900 RPMs. 3 speed/3.23 gears. Running Nitto street slicks. Admittedly this was my second time out so I may not have heated them correctly. I have regular shocks in the rear. and QA1s single adjustable up front which I set to their lowest setting. 17PSI in my rear tires.

I think I have a lot of upside if I can improve my 60ft. Everything I read says that a 11.7 pull should 60ft around 1.55/1.6. So I think I can hit low 11.s with some practice. What a blast, I can't wait for spring time to go again. My top trap speed on the day was 117MPH on a 12.1 run. Let me know what you think and any suggestions.

Also - I get my insurance through Hagerty. Does their normal classic car insurance cover any track incidents. I thought about that driving home that I should likely call them and check before I go next time.

60' foot times are always tough with a street car. 1.5 is extremely tough without slicks and a little suspension work. Vehicle weight is another killer.  The 60' time is the key source for low ET's unless you have some super pulling motor on the big end. The numbers your pulling are excellent street car numbers.   :ohyeah:

BillR1212

Thanks for the feed back guys. I'm looking forward to making some improvements. I think with any more traction I'll likely find the limit of my stock driveshaft/yolk/and u joint set up. I beefed up the u joint a bit with a conversation to a larger unit from Mancini racing. Still a 10 spring yolk. My driveshaft looks like it needs to be replaced next as it has some good dents in it that I'm sure are an accident waiting to happen.

I was hoping for low 11s with the new engine as it's pretty stout. I think it will get there with some traction improvements. Will keep it updated in the spring when I get to go and practice again. Before I go however, I think I'll get a drive shaft ordered to have laying around as I hear they take 4-6 weeks to build.

Bill R

Chryco Psycho

I f you get the 60' times into the 1.4 range i bet you also find the limits of the entire diff, I did .
Dana time  :bigthumb: