Reply With QuoteI have a single holley 750 double pumper on top of my tunnel ram and at full throttle after about 6 min it seems to be starving itself...I was thinking about putting on a electric fuel pump
I have a 455 olds .030 over, 512 lift cam with top end to match ,I have a single offy tunnel ram running a 750 demon carb. IS THIS ENGOUH carb for the motor, dont want to burn a hole in the piston. Thanks!
I have a single holley 750 double pumper on top of my tunnel ram and at full throttle after about 6 min it seems to be starving itself...I was thinking about putting on a electric fuel pump
Single carb tunnel rams are tricky... I had one on a 468 running about 8:1 compression. Was running an 830 Holley and it didn't run bad at all. Freshened the engine up and jumped to 9.5:1 compression and I couldn't get enough fuel to it on the top end, would go dead lean. Ended up wiping out the piston ring lands on the corner holes. They definately look cool, but are notorious for leaning out the corners.
you think putting an electric pump on would help? I have the high flow mechanical but not sure if thats enough. maybe need to jet up too. any other feedback would be good, thanks.
Get rid of the single carb top and put 2 x 4's on it before you burn up your pistons.
you think putting an electric pump on would help? I have the high flow mechanical but not sure if thats enough. maybe need to jet up too. any other feedback would be good, thanks.
You didn't like the answer I gave ya based on my experience??? Cool. I suppose you'll find out on your own then.
The fuel pump has nothing to do with not being able to get enough fuel to the corner holes, and I was running a bigger carb than what you're running up top. Good luck. Keep us posted.
Look at the first pic down below and see how the center holes are a straight shot down below the carb, versus 1,2,7, & 8. The air/fuel has to travel much further to get to those cylinders when you're running a single carb. I'm simplifying it a bit, but that's why they don't work well with a single carb in a high performance application.
Get rid of the single carb top and put 2 x 4's on it before you burn up your pistons.
Would that really happen??? :idea:
With this setup:
http://www.***boat.com/forums/attach...1&d=1212509785
low 80 mph on GPS, and dead lean up top. Could feel the boat lean out... a couple shots from the accelerator pump and it would pick up again. 6-7 PSI of fuel from a Clay Smith mechanical pump.
Oh, and this:
http://www.***boat.com/forums/attach...3&d=1212509844
Changed to this:
http://www.***boat.com/forums/attach...4&d=1212509912
90.8 mph on GPS and no falling off up top. Same fuel delivery setup.
the answer you gave was good , just getting a general concensus. I heard that the type of tunnel ram makes a huge difference offy vs. edelbrock for example. Deffinatly dont want to burn them up but the tunnel ram is all I have for now unless anyone has got a setup for my offy to adapt dual carbs. will I be safe if I keep the rpm moderate?? 4500 or so? appreciate all the advise you guys give, helps young guys like me learn
anyone else???
the answer you gave was good , just getting a general concensus. I heard that the type of tunnel ram makes a huge difference offy vs. edelbrock for example. Deffinatly dont want to burn them up but the tunnel ram is all I have for now unless anyone has got a setup for my offy to adapt dual carbs. will I be safe if I keep the rpm moderate?? 4500 or so? appreciate all the advise you guys give, helps young guys like me learn
The general concensus is that it's not a good idea... I just happened to include pics. As far as keeping your rpm's moderate, you don't have much of a choice in that anyway as you're running an Olds, and if you do a search you'll find hundreds of threads about the oiling problems they are notorious for, and the fixes for that, such as oil restrictors for the top end, auxillary oil returns to get the oil back to the pan, huge oil pans.... Take an Olds out and run it hard for a long time and all the oil will end up in the top of the engine and it will grind to a stop. The mods just minimize the chances of that happening as soon.
Good luck with your project. There is lots of information in this forum and in the gear heads section. The search button is going to be your friend now that this place is somewhat of a ghost town.
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