Fuel System - gas and alcohol
 

I have a question regarding fuel systems.
I currently run a gas system with a rear mounted fuel cell with an electronic Product Engineering pump and regulator. Can you run alcohol with this set up to a alcohol carb? The pump is rated for both. I have been doing some reading on the subject and it seems that most recommended system for alcohol is a front mounted tank with a belt driven pump.
Any thought or duggestions would be greatly appreciated.
Thanks

I'm hesitant sometimes in answering this question because invariably someone will chime in and say I'm full of crap and that this won't work. So what I will say is that it works for me. Your mileage may vary!!

A couple things first. A belt driven pump with a front tank is a simpler system IF you have room on the front of your motor for the pump and room up front for a tank AND you don't mind taking the hood or in some cases the whole front off the car between rounds to refuel.

BUT...

...if you already have an electric rear mounted fuel system with adequate sized fuel lines and a sufficient pump, then yes it will work. Keep in mind that you will need to deliver almost twice the amount of alky to the motor than gas.

Here's my setup:

A 4 gallon rear mounted fuel cell
BG400 electric fuel pump
Holley 12-704 regulator
Rupert modified 1150 Dominator with PCI fuel bowls
-12 line from tank to pump
-10 line from pump to regulator
-8 line from regulator to carb

I have also run this same setup with dual Holley (Rupert) 750s with standard fuel bowls. I have the PCI bowls on the 1150 because they have 2 .150 needle/seat valves in each bowl plus the bowls are a little larger. Again, we're dealing with twice the amount of fuel and that's the key with alky. You've got to get enough of the stuff to the motor. I have got mine to work with 8 psi fuel pressure but you really need about 9.5-10 psi of fuel pressure to the carb at WOT. You won't be able to do that with a carb as you will blow the needles off the seats and flood the motor unless you do a little mod to the regulator. I have only done this to a Holley 704 regulator but it will work with others. You need to take the diaphram cover off the regulator and drill a 11/64 hole in the side and then tap the hole with a 1/8" NPT tap. Put a AN4 to 1/8 NPT elbow fitting in that hole and then drill and tap your intake or carb spacer and put another elbow there. Connect the 2 fittings together with a AN4 line or you can use rubber line and hose barb ends of the elbows if you don't want to use the AN4 line. When you crank the motor up, disconnect the line from the intake and plug the intake or have a helper hold their finger on it and then set your fuel pressure to 9.5-10 psi at the regulator. Then connect the line back to the intake. You will find that for every inch of manifold vacuum you have at idle you will have a 1 psi DECREASE in fuel pressure. This will get your fuel pressure down where you don't blow the needles off the seats at idle. When you open the throttle, intake vacuum drops and you will see your fuel pressure rise. At WOT where you have very little to no intake vacuum, your fuel pressure will be where you set the regulator, i.e., 9.5-10 psi. At this point you don't really care if the needles are getting blown away as you will be using all the fuel you can pump in there.

As I said above, you can get by with 8 psi and not have to do the regulator mod if your carb has 1:1 linkage where the secondaries open with the primaries. Otherwise, what I have found is that doing the burnout with a carb that has the old style progressive linkage, you are really using only the primary bowls as the motor doesn't have enough load on it to have the secondaries open and you run out of fuel in the primary bowl. If you have the 1:1 linkage then both font and rear throttle blades are open the same amount burning fuel equally out of both bowls and that will work fine with 8 psi.

Does it work? I run a 496 in a 2546 lbs. Camaro to a best of 5.46 @ 125.77 in the 1/8th with a 1.18 60'. It works for me and as Forrest Gump would say, "That's all I gotta say about that."

George

That was awesome dude, very well written and very informative. I really liked the regulator trick too, thats a very good idea. I hope to convert my 496 to alky next year and I wasnt to thrilled about possibly having to relocate the fuel cell and everything else. I'll definetly dig this post up and refer back to it when I do.
Thx, Charles

Thanks Charles. Glad it helped.

George

George - Thanks for the information
Sounds as if it would simplify things to get a 1:1 carb.

What Jets to use in a 1050 alcohol Dominator on a 489 BBC???
 

Hello,
This has been very informative and I thank all who have written.

My question is about tuning...
I just bought a Rupert Alcohol 1050 Dominator and enderle belt driven pump which I will mount under the hood of my malibu. The carb came off a 540 but I am running a 489 BBC. Does anyone have any idea what I should be running for jets front and rear?? I dont want to flood the engine.

I have run enderle injection standard and blown alcohol but this is my first attempt at an alcohol carburetor.

Any help would be greatly appreciated!

Thanks,
jp

I don't think you have to worry about flooding the motor. I had a float stick once and had raw alky pouring out the collectors with the motor running. :D :D

On the tune it depends on how Rupert set them up but it all boils down to how much air you are able to pull through the motor. The last carb he did for me was the 1150 I run now and I have 184 jets front and rear. I had a 1050 he did and I think I had 180s in that. I have a friend running a small block that has 209s in it. That will get you started. You want it jetted to pick up somewhere around 5-10 degrees water temp on a pass. More than 10 and you're too lean. Less than 5 and you're a little on the fat side. If you're looking at EGTs, ideal for mine is between 1050-1100 on an eighth mile pass. It's not unusual to see upwards of 1300 in the 1/4. Rupert will be the first one to tell you to throw the EGT away and jet the thing for max MPH. BUT, for consistancy, alky likes to be on the fat side. You won't run as fast but you'll be more consistant.

George

JP, I think that is too fat, 154,s would be my chioce with a 496. I ran a 1050,1150 and 1250 on my 565 with never bigger than 165,s. Call Rupert and ask him whatever he tells you will be a little fat!

I'd listen to George

George Knows :P

Guys please fill out your profiles,atleast tell us your location,State would be fine Thanks

Tom

The reason you can use a smaller jet is because you have a larger motor that is pulling more air through the carb at a faster rate and this rate (velocity) will determine what jet you can use. I think you will find that, in general, the smaller the motor the larger the jet has to be with a similar sized carb. But that's just my experience. In the end, it doesn't matter what I, Rupert, or anyone else says. The motor will tell you what it wants. All you have to do is listen to it.

George

Wait a minute, Bigger engine pulling more air with more velocity but less fuel, that does not make any sense to me and I have been running alcohol for 15 years.

Tom, Do you run a smaller jet than the guys with smaller engines?

George, What size pump do you run?

Nope, I didn't say less fuel. I said less jet. I'll see if I can explain it a little better. Let's say you and I both have 1150s, your 565 and my 496, and we both have 165 jets installed. If you're right on then I will probably be lean. Since you are pulling more air than I am you are pulling more fuel through that 165 jet than I will be able to. Since I can't increase the airflow through my carb my options are to increase the jet size or go to a smaller carb to get the velocity of the air up. Air velocity through a venturi is suction. The more suction you have, the greater the pressure differential, and the more fuel you can pull through a given restriction, in this case the 165 jet. I don't have the velocity so I need less restriction, i.e., a larger jet.

BTW, I'm running a BG400 pump.

George

I would be more inclined to believe that with an electic fuel pump you need a bigger jet for more volume due to the lack of volume the pump delievers. Have you ever ran a mechanical pump with your set-up. Years ago i bought an alcohol carb from Barely Grant. I had a Barry Grant pump and they told me it wouldnt work and they were right. Have had a mechanical pump every since. I do not believe you need that bid of jet with an Enderle pump.

Zipper, where are you i need you to jump in here !!

I can tell you that what George is saying is the exact thing I am going through right now. We have an older Rupert 950 that we had on a 468. It had 165 jets in it, I put it on my 383 that is a lot milder motor that the 468 and have had to go up to 173 jets, went quicker and faster than with the 165s, and I am going to go up even more the next time out. I am using an electric pump also. The one thing that I will have to watch with an electric pump is emptying the bowls faster that the needles will let fuel in with the bigger jets because I can't raise pressure with rpm like a mechanical pump, even though that is probably the better way to go.

Curtis

I rest my case! Find me someone who is running that big of jet with a belt drive pump, you wont. The guy in question here is running a belt drive pump. If you run the right fuel system you wont need all that fuel pressure bleed off crap, just set the fuel pressure and go!!

Sorry i'm not alcohol carberator person, but i am a firm believer in front mounted mechanical pumps. My car is setup both for gas and alcohol. I have an 8 gal fuel cell in the trunk and 2 holly blues, and a 1/2" feed line, regulated at 8lbs. I also have a 3gal. cell in the front for alcohol running the toilet bowl with a DSR mechanical pump. If i were to put an alky carb on i would use the mechanical pump and regulate it with an 8lbs bypass off a fuel log/tee. 1 line out of the pump 1 line back to the tank. Real simple setup and cost effective, and you will never run out of fuel in the carb.


just my .02

Zip.

Obviously the pump, whether electric or belt driven, needs to be sized correctly but in your statement above if a pump lacks the needed volume adding a larger jet for even more volume would only exacerbate the problem. Electric pumps work fine if the pump is big enough. That's all I have run. I do have the PCI bowls on my carb so supply is not a problem.

Curtis, you are going in the right direction.

George

I dont care what masterbates the problem its all about electric verses belt drive pumps. You are sending JP in the wrond direction!

The guy in my post above that had 209 jets installed is using a belt driven pump. I didn't invent physics I just have to apply them like everyone else. I don't intend on getting into a pizzing contest on which pump is better. Different type pumps require different setups. Like I said in my original post, it works for me. If it doesn't work for you that's fine, too. And I'll let it rest with that.

George

I agree 100% with Davis

Every carb and motor setup is different but IMO try anything from 154 to 168 in that Rupert

Zip

I have a mechanical pump at home and if I had a cell up front I would run it in a heartbeat. I have made my own throttle body to run injection but haven't gotten around to putting it all on yet because of the amount of work it will take to put a cell in the front of my roadster and to mount the pump. Just not much room there.

Curtis

Put your belt drive pump and a bypass on with your carb, leave the fuel cell where it is, and problem solved ! Then go race and be consistant.

Curtis, another way to do that is leave your cell where it is and still use the electric pump, to a small reserve tank up front 1 gal is plenty. I've seen alum hand made tanks with a holly c'pivot float bowl mounted to the tank to control fuel level in the reserve tank, just remember to use a min. of #8 and preferrably a #12 feed line to the pump. i use #8 on my toilet bowl but #16 on my blower motor. i've got 5 different pumps from a hilborn 0 for gas up to an an Enderle 990, just in case i want to throw a little pop in the alcohol.

Zip.

C'mon guys. We're not talking fuel injection here we're talking carburators. The only function a fuel pump has on a carbed motor is to keep the fuel bowls full, period. It doesn't have diddley squat to do with what flows through the jets as long as the bowls are full. The bowls don't care where the fuel comes from or how it got there as long as they are full.

I don't know why it's so hard for some of you to understand that some of us, myself included, have absolutely no room up front for a fuel tank without some MAJOR modifications. If I did I'd be running a belt drive pump but I don't so the electric is the only way. But if you look at the times I have posted in my sig I don't think my car is hurting any.

George

Zip,

I've seen the surge tanks set up just like what you are describing. I make our own aluminum cells and sheetmetal valve covers that I used to sell, so making the tank and getting it set up is not a problem. I understand what is needed (although I appreciated the intended help). I don't want to add the weight and complication just to run the injection. I will add a frame for the cell and aero nose to the front to cover it when I decide to inject it, but don't want to do it until racing season is over. Thanks for the reply.

Curtis

Why is it that you think you have to have a fuel cell up front to run a belt drive pump? Remember it is a carbuerator with fuel bowls not injection. I now run a 1250 Bolaws with a Bolaws belt drive pump with a bypass built into the pump. I dont even have to use a return line. My fuel tank is 10" from the pump. My point is you said you have never ran a belt drive pump yet you continue to tell us we are wrong. My car runs 4.70,s and will repeat againand again and again will yours? Does that make me right,NO!!! What makes me right is that i have experience running an alcohol carb with a belt drive pump. Do you bracket race or race heads-up.

Davis,

I never said you have to have the fuel cell up front to run a belt drive pump, but as you know these were not made to suck from the back of a car. My cell is a lot further from the pump than 10". Is your cell in front of or behind your pump? I do remember this is a carburator with bowls. I never said I have never run a belt drive pump! I AM IN NO WAY SAYING YOU ARE WRONG. I just agreed with George's point when it comes to way carburators react on different size engines. I am seeing these results.

There are 3 cars that I own part of and race. All bracket cars, '66 Nova with Ron's toilet sbc, Victory dragster with belt drive pump and carburator 468, and my '27 roadster with electric pump and carb sbc. So I do have experience running all three combinations. I'm glad you car will run 4.70s, I truly mean that. But I also don't care. You do have a nice looking car and I'm sure you are happy with the way it runs. My car won't run 4.70s but that doesn't mean I'm an idiot about this stuff either.

I don't understand your reaction to the things I have posted because none of it was directed at you personally. I know there are different ways to do just about everthing and get good results. Remember I am not saying you are wrong only posting my opinions, surely nothing for anyone to take offense at.

Curtis

Curtis, This post was not meant for you it was meant for George, my mistake i should have adressed it to George,Sorry! I have plenty of friends who run belt drive pumps with the tank in the rear of door cars with no problems. One friend of mine runs a 56 Chevy with a 468. Rupert 1050 and enderle belt drive pump with 144 jets and i have seen him repeat 6 and 7 times in a row. Hell i have seen him repeat to the thousand 4 times in a row. Again that post was not meant for you. It is your car and you can do whatever you want with it. I just didnt like George telling me i was wrong when i run the fuel system you were asking about and he does not. Thank You, Don

Here are the comments i was referring to!

Hey I'm sorry I misunderstood. All us Okies and Texans at the racetracks have to get along, there is enough bad blood on the football fields. LOL I hope to catch you at a race someday and say hi.

Curtis

Don,

We were originally talking about carb jetting and then you got on this fuel pump tangent. I have said in my previous posts that my findings were based on my own experiences and that "in general" a smaller motor will take a larger jet with the same sized carb than a larger motor. They're are just too many variables that determine how much air a motor can pull from one motor to the next BUT I think that if you take your carb off your 565 and put that same carb with the same jets on say a 434, the 434 will need to be jetted up. The statement you made where I definately think you are wrong is below:

I know guys who are running belt drive pumps with larger jets on smaller motors. The guy I mentioned who was running the 209 jets runs a bolaws pump on a 434 small block. As I said before, the carb doesn't care where the fuel comes from or how it got there. The bowls just need to be full. That's why I said I didn't want to get in a pizzing contest about which pump is best. They both, belt driven and electric, can be made to work. What's best for you is not neccessarily best for me or someone else where the configuration of the car won't allow for either the mounting of the pump or the tank or convenient access to a front mounted tank. I, too, have been told not to run a belt driven pump with a rear mounted tank but if it works for you then, hey, that's great.

Don't get your panties in a wad just because someone disagrees with you. Hell, you disageed with me and you don't see me getting an attitude. The starter of this thread wanted options. I gave him options that work. How do I know they work? Because I'm doing the same thing. How do I know that a 154 jet is probably too lean? Because I have already tried running them. How do I know that 184 jets are the correct jet for my motor? Because on a 95* day on a 1/8th mile pass, 1109 on the EGT and a pickup in water temp of 7*. Again, just my experiences. Your mileage may vary.

George

Like the others mentioned tough, it's NOT good to start an alky engine unless you can get the water temp up to about 210 before you cut it off as there's not enough heat to help dry it out otherwise. One more thing I do is to prop open the throtle blades to allow inside the cylinders to dry out also. I've pulled more than one alky engine down and found rust pits in the cylinder walls and valve seats. A little WD-40 also helps down the intake while rolling the engine over with the starter.


This is a quote from Ken on your website under Fuel Systems
You know George after reading some of the post on your website i can see where you are coming from, like this one from your buddy Ken!!!!

I would never dream of getting my water temp up to 210 degrees for any reason.

OK. I'll bite. Care to tell me why? I'm always up for learning something new.

George

This should possibly be in a seperate post but I think your topic of discussion may apply to my questions. A friend of mine has a 2850# door car that has a 460” BBC on Alcohol and runs 9.30-9.40’s @3500’ and 9teens @ sea level. It has never ran quite as good as we feel it should. He is using his existing gas delivery system, a rear mounted BG400, ½ line @ 28#’s to the front of the car, regulated to 11#’s dead headed at the bowls. It drops to about 9 #’s though the top end. The EGT’s are always over 1200c at the 1/8 th and 1300 to 1320 at the ¼. The probes are 4” from the header flange. It has an out of the box 1095 Alcohol Demon, but he recently went up to 200 mains. The car picked up a little but the EGT’s are still hot. It has allway had a slight flutter at the top end (even after freshening the motor). Do you think that it is still a bit lean on the main, or is it possible that his gas based delivery system isn’t keeping the bowls full. I would think that 9#'s is 9#'s.
Details of the powertrain: 335CNC AFR heads, Reher-Morrison Super Victor CNC intake, 1095 Demon Alcohol carb, Bullet roller .830/.775 283/294 110LC in at 108ILC, 13:1, 38degrees total, 2 ¼”X28 3 ½”collector, 1.80 low gear set, 4:88 rear, 103 rollout tire, 7500 through the lights.
What do you think of the 1095 Demon on Alcohol. Do they work well out of the box, or is it worth the money to have it reworked by ProSystems or Rupert or ??? Would a Holley reworked by one of these guys perform better? What about a smaller plenum intake (ie RM Funnel Ram) to avoid puddling. Smaller 2 1/8” primaries”.
I like the vacuum to the regulator spring housing idea. Way to simple. We will do the reg mod for the weekend, and he has bigger mains coming as well. Just looking for some suggestions for down the road.
Thanks Tom

I dislike that intake for that combo. I've also never been a fan of a demon alky carb, your egts are to high I shot for 1100-1150 in the 1/4. I'd send it to APD or Rupert to conv over not Prosystems if it was gas then Prosystems.

Thank you for the reply. Which intake didn't you like for the small motor? The Super Victor (I suspect a little large), or the RM funnel ram? What would you suggest?

Tom

454R out of box. good intake

There is a reason why they are called the fastest caburator in the world

http://www.pro-system.com/friendlydom.html


:P

I don't have any experience at all with the Demon carbs so don't know what to tell you there other than Rupert has done all my alky carbs.

I agree with Hammer about the intake. I run the Super Vic and I think it's a great intake but might be just a tad big for a 460 with those heads. You might try a Victor Jr. with a carb adapter but that's probably close to the RM manifold you're looking at.

If you call Rupert he will tell you to forget about the EGT. He has told me examples of carbs he has put out that ran 1200+ in the 1/8 and he was fine with it. He thinks there are too many variables in the EGT systems and installations. He will tell you to jet it for best MPH and let the EGTs fall where they may. Still makes me nervous to see them up there though. :)

Are you running any kind of spacer under the carb? If so you may want to try it without the spacer.

What type of hood scoop are you using and are you running an air cleaner or a carb pan sealed to the scoop? If you're running an open front ram type scoop with no air cleaner or pan, the air flowing over the top of the carb can actually suck fuel out the top causing it to lean out and could cause the flutter you mentioned.

I run 10 AN line from the pump to the regulator and 8 AN to the carb.

Let us know how you make out.

George