octane booster

[red 69 runner]

Just curious if any body uses octane booster in their cars and if there are any benefeits or hazzards to using the stuff.I run 93 octane premiun in my stock 383 with 10.0to 1 compression .the car runs good but the only problem I have is when its fully warmed up and shut down for 20 or 30 minutes its hard to start from what I have been told is because the fuel boils out the carb.I saw on another forum a guy said he mixed the higher octane cam2 with his 93 octane and the problem went away due to the higher octane mix haveing a higher boiling temp,anybody have any thoughts.

 

[69hemibeep]

Just curious if any body uses octane booster in their cars and if there are any benefeits or hazzards to using the stuff.I run 93 octane premiun in my stock 383 with 10.0to 1 compression .the car runs good but the only problem I have is when its fully warmed up and shut down for 20 or 30 minutes its hard to start from what I have been told is because the fuel boils out the carb.I saw on another forum a guy said he mixed the higher octane cam2 with his 93 octane and the problem went away due to the higher octane mix haveing a higher boiling temp,anybody have any thoughts.

If you have ethanol in your gas I don't think your going to get enough octane boster to help. Try a fiber spacer between the carb and manifold it also helps to block the cross over on the intake.

 

[red 69 runner]

Thanks,I am looking into that right now.

 

[A31PKG]

Just curious if any body uses octane booster in their cars and if there are any benefeits or hazzards to using the stuff.I run 93 octane premiun in my stock 383 with 10.0to 1 compression .the car runs good but the only problem I have is when its fully warmed up and shut down for 20 or 30 minutes its hard to start from what I have been told is because the fuel boils out the carb.I saw on another forum a guy said he mixed the higher octane cam2 with his 93 octane and the problem went away due to the higher octane mix haveing a higher boiling temp,anybody have any thoughts.

If you have ethanol in your gas I don't think your going to get enough octane boster to help. Try a fiber spacer between the carb and manifold it also helps to block the cross over on the intake.

X2

Also an in-line electric "helper" fuel pump works wonders. Especially after they sit a spell....

 

[moparstuart]

I have to run Lucas octane boost to keep my Six pac motors running well and not pinging

 

[sixgunrunner68]

I have to run Lucas octane boost to keep my Six pac motors running well and not pinging

x2 I'm using the same stuff.

 

[red 69 runner]

Thanks guys,I just ordered a spacer from cool carb .com and also am going to change my manifold to an aluminum dual plane and block off the crossover.Ill let you know how it goes after the change.

 

[generaljmwlee]

saw this at carlisle looks good
www.coolcarbs.com

 

[generaljmwlee]

didntsee you already found it! :jester:

 

[moparchris]

I mix VP110 with pump gas and have no problems. I was using an octane booster but the engineer from Rocket fuels said that octane boosters dont work very well and have mixing problems.

 

[69hemibeep]

I mix VP110 with pump gas and have no problems. I was using an octane booster but the engineer from Rocket fuels said that octane boosters dont work very well and have mixing problems.

My little runner likes that blend also :yesnod: and Its at 10.25-1 with a little different head

 

[zupanj]

Octane booster will help with pinging which is pre-ignition but I don't see how it could help with your problem. I have had this problem with both the 383 that was in my Runner originally and with the hemi that's in there now. In my case it takes a really long time to get the car to start if it has been sitting for a week or two. I don't think that cranking as much as is required to start the car can be good for the internals but I don't see many options. I added spacers but that doesn't seem to do much and certainly not after a long shut down. I considered an electric pump in front of the mechanical pump but most of the folks on Moparts said that was a bad idea though a couple of guys seemed to have good luck with that setup. When you think about it, the mechanical pump should fill the fuel bowls pretty fast anyhow.

I have heard several people say the ethanol is boiling off but that is probably not the case since gasoline boils about 20º C lower than the alcohol, it would go off before the ethanol. Ethanol raises the octane rating of gas by quite a bit in fact.

I will be curious to hear about your experience with the carb spacer.

 

[A31PKG]

I considered an electric pump in front of the mechanical pump but most of the folks on Moparts said that was a bad idea though a couple of guys seemed to have good luck with that setup. When you think about it, the mechanical pump should fill the fuel bowls pretty fast anyhow.

If the car is going for O.E. judging, then I see their point... Otherwise, IMO the best way to rapidly fill an empty carb bowl (either due to a hot-soak restart, sitting/storage, racing, fuel type, etc) is with an electric in-line "helper" pump. Not fuel injection pressure, mind you, just around 5 psi or so..... :cents:

 

[zupanj]

Otherwise, IMO the best way to rapidly fill an empty carb bowl (either due to a hot-soak restart, sitting/storage, racing, fuel type, etc) is with an electric in-line "helper" pump. Not fuel injection pressure, mind you, just around 5 psi or so.....

What kind of system are you using? Pump, regulator etc. ?

 

[moparchris]

1137 mm Hg vapor pressure of VP 110
275-475 mm Hg @ 68 oF (20 oC) for pump gas also known as E15.
43.7 mm hg vapor pressure of ethanol.

I think whats happening to our cars is that the Ethanol is remaining in the fuel bowls while the gasoline evaporates. This causes a mixture imbalance and you end up with pure methanol in the bowls. Of course the fuel mixture will be too low to ignite and it takes an extended cranking time to exhaust the ethanol and replace it with the E15 blend. Where as pure gasoline will evaporate and allow the carb to be refilled immediately. Just a thought. The vapor pressures above tell us exactly who evaporates faster. The higher the number the more volatile the liquid is.

 

[A31PKG]

No regulator, just a 5-6 psi unit that I picked up at NAPA. There are a few suppliers out there; Delco, Bosch, among others...They run around $50-$75. Very simple to hook up & hide. Mine is above the rear axle on the shock crossmember. It's on all the time (with the key in "run") but pumps only as needed. I have it wired to the "run" circuit on the back of the fuse box. Ran a fused black 10g wire along the left side rear wire harness under the threshold plate to the back of the car. Poked a hole in one of the smaller trunk pan plastic plugs (by the spare tire) and ran it to the pump. After a long sit, I just turn on the key and let the pump run a bit - maybe 10-15 secs - pump the gas 2-3 times and she fires right up. The stock pump is still there and entirely functional. My "hot soak" issues were cured with a carb insulator & exhaust block offs in the intake gasket. These are all relatively "stealth" mods BTW.

 

[V269]

Carter electric pump mounted above the rear axle and no mechanical pump for my car and it starts no problem every time.

 

[sixgunrunner68]

Carter electric pump mounted above the rear axle and noon mechanical pump for my car and it starts no problem every time.

X2 on the Carter, but I'm also using a mechanical Holley up front.

 

[A31PKG]

Yeah, just checked mine - it's a Carter also (couldn't remember at work today). The part # is P74029. Here's a pic of it installed:

 

[zupanj]

Chris,

I am inclined to agree with your thought that the fuel bowls contain only ethanol which doesn't fire easily.

A13PKG,

I found your pump on Summit but it doesn't show the psi, I don't think you would want it much above 4psi if you keep the mechanical pump. Is it OK to mount the pump higher than the fuel tank?