Is this fuel starvation or otherwise?

Do you like to go fast? Well get out of that stocker and build a hipo motor for your VW. Come here to talk with others who like to drive fast.
Richierich
Posts: 15
Joined: Fri Jan 06, 2017 4:41 pm

Is this fuel starvation or otherwise?

Post by Richierich »

I have a 2276 type 1 motor in my street /strip Oval.
- Carbs are 48 IDA's with standard float bowls;
- Facet Gold Flo electric fuel pump mounted under the tank;
- stock fuel line through tunnel then as photo below;
- Cam is a Web 86C;
- Have a Malpassi petrol king pressure regulator which is set to 3psi (my gauge has not been calibrated so this figure could be somewhat off and the real figure could indeed be slightly lower if anything);
- Ignition is a Pertronix billet distributor.

Here's the issue - when I floor it, at around 5800rpm it falls on its face. When I first had the motor built and dyno'd it made power to 7400rpm and I ran it to that a good few times so I know it's there. I had a Pertronix billet distributor in it at first and then changed to a CB Magnaspark - which is when this problem manifested itself. I have since changed back to Pertronix (not the one I had originally) and it's still doing this thing. It almost feels like the spark is being cut like a rev limiter (i do have a limiter but it's set at 7200). It will do this in all 4 gears.

In a long winded way, my question is, could this be fuel starvation or is that unlikely? Should i try bumping the fuel pressure up 0.5 psi at a time and see what effect it may have?

If not that, any idea what else is likely?

I am interested to know how quickly the bowls can be drained at wide open throttle aswell.

If anyone can give me any advice on this, I'd really appreciate it - it's quite a frustrating issue.

Image
User avatar
Clatter
Posts: 2046
Joined: Sun Apr 28, 2002 1:01 am

Re: Is this fuel starvation or otherwise?

Post by Clatter »

Theoretically your setup should feed your motor.
If it had done so in the past that theory is correct.

Doesn’t mean your filter sock isn’t clogged or the line partially plugged or something.

You can take a long remote stretch of road, wind it out till it stumbles, kill the motor (and fuel pump) and pull to the side of the road to take the tops off of your carbs and see.
That will tell you for sure if it’s a fuel delivery issue.

Also common to have too small of a tank vent - loosen gas cap to see if problem goes away.

If the carbs are full, then ignition might be the next thing to look at.
Did you use the same coil with both ignitions?

Had me a bad wire once too.
Running a jumper from batt+ to coil temporarily bypassed and showed the culprit.
Black ignition wire has no fuse and therefore known as ‘old crispy’..
Speedier than a Fasting Bullet!

Beginners' how-to Type 4 build thread ---> http://shoptalkforums.com/viewtopic.php?f=1&t=145853
Bruce2
Posts: 7100
Joined: Sat Oct 13, 2001 1:01 am

Re: Is this fuel starvation or otherwise?

Post by Bruce2 »

Clatter wrote: Sat Apr 27, 2019 7:01 am ... take the tops off of your carbs and see.
There's no need to remove the carb tops. You can just look down the vent hole to see the top of the brass float. Look before the run so you know where it should be.
User avatar
richie,uk
Posts: 353
Joined: Sun Jun 16, 2002 12:01 am

Re: Is this fuel starvation or otherwise?

Post by richie,uk »

Hi Rich
I wouldn't think it was fuel starvation if it does it in 1st gear as well, if you run it flat out until it dies then shift what happens in next gear? is it ok again until 5800rpm still? or dies straight away?

cheers Richie
Richierich
Posts: 15
Joined: Fri Jan 06, 2017 4:41 pm

Re: Is this fuel starvation or otherwise?

Post by Richierich »

richie,uk wrote: Sun May 05, 2019 9:44 am Hi Rich
I wouldn't think it was fuel starvation if it does it in 1st gear as well, if you run it flat out until it dies then shift what happens in next gear? is it ok again until 5800rpm still? or dies straight away?

cheers Richie
Hey Richie - going to try and get down to see you in the next few weeks either way. I had the car out this weekend and after messing with the regulator, it seems that the issue is now sorted.
User avatar
richie,uk
Posts: 353
Joined: Sun Jun 16, 2002 12:01 am

Re: Is this fuel starvation or otherwise?

Post by richie,uk »

Cool, see you soon then :)
Post Reply