Holly fuel pump and carbed 308

Do not exceed 3 psi (2.5 is best) with DCNF webers.

 

You will need a regulator with a red top Holley; However, the Holley regulator and pump sometimes act funky and confused at low pressures in a continuous loop system such as a 308. I have personally heard AND seen this, so be careful. Perhaps a different make of regulator may work better.
If you can take it back, you can swap it for the same price or less large Facet pump, which requires no regulator and is the standard preferred replacement for the original Corona in the 308 application.
Another good but less well known fuel pump I am told is the low pressure Carter pump.
Good luck
Russ

 

The pump on my '78 308 finally bit the big one...I was looking for the Facet pump, but discussed it with my race car mechanic. I had a spare Holley pump (red). He told me that he's tested them and they run about 4-5 psi. I put it in my car about 2 weeks ago, and it transformed the car (which I've owned for about 8 years) I guess the old pump never was quite right. Now I have no hesitation at all, and it idles much better (in fact perfectly - which it never did before). I did not add a regulator. The book says the pump should be 3 +/- .5 m H20. I believe this equates to 3.5 - 5.0 psi. It seems to me that the Holley is very well suited, and is pretty much a bolt in replacement. (slight rerouting of the fuel lines). Is there something here that I'm missing. I'm not sure why some are recommending less than the book on pressure. Thanks, Jim

 

I just read the article on the link you loaded. Thanks. The Carter sounds like the best solution, but I have to tell you...My car runs great with the Holley. Maybe mine runs closer to the recommended 4 psi. Thanks for the information.

Jim

 

My understanding is that too high a pressure will end up changing float set up, I am by no means an expert in webers but the books (that I have) and the folks at Pierce Manifold all agree that 2.5 to 3 psi (maybe 3.5 at very max) is all you want to run. I have spent the last two weeks buying, installing and removing regulators and finally think I found a working one at jegs part #027-13301 (3 to 20 psi return type as I have learned with great frustration that Dead Head regulators suck!) I used a mallory filter 1st and then pump set up by modifying the old pump base as shown below....I am feeding four 48mm webers so I need a higher flow rate.

Russ seems to be the resident expert on Weber set up as he has lately eat, drinken and slept with them if you have followed his prior posts so I would defer to him on anything Weber. (with the exception of short stuff )))

Paul
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I bought that pump at Napa for about $50. I think it was for a Fiat. It works great!

 

I'm not really an expert, but I sure enjoy working with them - they are so supremely elegant little pieces of engineering. Just when I think I know them, they show me I really don't. I guess it would be 'La' Weber (italian feminine article).
It's interesting that many folks as well as I have had some difficulty with regulators. Perhaps that colored my view of the Holley pumps, because I only ised a Holley regulator.
I may switch to a Carter as well - the Facet is working terrific, but that thunka-thunka thing is getting annoying.

The twilight zone for most street low pressure pump is around 300 hp. Paul's engine, a full up race spec Weber 3 liter qv dips above with a very high flow at low pressure is really quite interesting. A big lesson here is that low pressure regulators in return flow systems are difficult applications.

What a zinger! I laughed out loud for 5 minutes.

 

FYI, Pierce told me once that 175 needles will work to about 320 BHP (stock pump). Let me know if you want to try the 200s, Russ.

Paul, I don;t know the IDFs, but my guess is there's a balance of flow pressure (pump psi) and float bowl filling rate (needle jet size). Just a thought.
Philip

 

Philip
Many, many thanks - not sure what to do.
To keep the torque profile I would like, I don't see going all the way to 100 hp/liter (320 hp). With Pierce saying that the 175 needle valves will work to 320 hp and Carobu saying 34mm venturis work to 320 hp, in theory I ought to be ok, even with the newer higher lift, longer duration camshafts. And the new linked information from this thread that the quieter Carter pump is good to over 300 hp kind of has me settling on a specification: 300 - 310 hp with max low end torque. Although still with stock 3.2 cams and 15 or so less hp, I'm still currently putting out as much or more torque as a Mondial 3.4 t as shown by dyno in another thread. Not a bad thing. Makes me just want to add lift and not much more duration on the new cams for street use.

That said, I'm not sure if it wouldn't be 'easier' for the engine to breathe and perform if I went ahead with the new 200 needles and 36mm venturis. Even with the stock cams, it tolerates 36mm venturis fine except for a very minor transition flatspot around 3800 rpm, really only noticible during small throttle movements where the honkin' big -12 accel pump cam doesn't come in and cover (more about this in another thread - I felt so proud of myself figuring out to correct for this by tweaking the intake velocity... ). Will contact about you kind offer based on what the new cam A/F charts suggest.

So, staying with the thread topic, once you start getting much above 300 hp, the pump/needle valve combo starts entering a transition zone. That's the trail Paul is mightily blazing, as he is easily screaming over 320 hp I'm guessing being privy to the 48 IDFs, King Kong Kams, Kwatrovalves and Kompression. Even the 308 GT/LM engine used 175 needle valves with 36 mm venturis, and that engine was probably over 300 hp. Intuitively, a rotory pump ( Corona, Holley, Carter, SU, Bendix..) seems best suited for a return flow set-up as in the Ferraris, with the Facet plunger style better suited for non re-flow applications (e.g. Alfas) - although I'm told with fewer moving parts, the Facet (also used in aviation) is very reliable, and that is a big selling point for me.

best
rt
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BAD is an understatement regarding that regulator....wasted 10 days with it and it had me questioning basic flow and pressure theroy that has been in place for some 400 years. I have never seen a pressure gauge move all over the scale like that.

Will know if the Jegs/Aeromotive regulator one is correct in a few days when I finish plumbing it in. I can't see how it could not work but since everything else has gone backwards in the past week....who knows. 3 weeks of designing and plumbing a 110 gallon an hour 3 psi fuel system is a bit frustrating!
heck Phillip dry sumped and en engine in that time and Russ went to an imbedded internal velocity system in less ;-) (don't ask..no more I promise).

Off to Ferrari world for another day of fun in fabrication.
FFF=Fun Ferrari Fabrication or "I need a Bigger Hammer".

 

Yes - I think it took about an hour to go from 36mm to 34mm venturis.

 

Doug
Thanks for the update.
I just got a Carter 4070 at my local speed shop for $76, and will try it over the reliably effective but somewhat loud abdominal-gas sounding Facet.
Do you have a spare bracket ( ) or a prcture of what you used? The stock bracket does seem a bit hefty.

Many thanks
Russ

 

Doug - very nice installation! You do still have the return flow system?
Will see what I can do.
best
rt

 

Yes, there is a small fuel line returning unused fuel to the tank. This constant flow of cool fuel helps to prevent vapor lock.

best,
Russ

The below is gleaned from a 308 GT/4 parts book:
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