Fan to carburetor intake

Michael Hunter

Michael Hunter

True Classic
Hi everyone,
I tried to find info on here and could not find anything to answer my questions. If there has been previous discussions, may be I can be directed....I am wondering about the purpose and effectiveness of the fan/blower that is hooked to the carburetor intake. Is it necessary? Has anyone deleted theirs? Pictures of what has been done for the intake would be great. I was thinking of just ducting straight from the side air scoop to the carburetor breather.
 
That fan only run's when the key is turned off. Many people have deleted it. Its purpose was to try to stop the fuel from boiling off in a heat soaked engine bay.
 
Ha, that reminds me of times when I would be walking away from my car and someone would tell me my car was still running....
I think I removed that fan from every X I've owned with no issues.
 
Michael Hunter said:
Hi everyone,
I tried to find info on here and could not find anything to answer my questions. If there has been previous discussions, may be I can be directed....I am wondering about the purpose and effectiveness of the fan/blower that is hooked to the carburetor intake. Is it necessary? Has anyone deleted theirs? Pictures of what has been done for the intake would be great. I was thinking of just ducting straight from the side air scoop to the carburetor breather.
Click to expand...

As Rod points out, it is to keep the fuel in the bowl from boiling out. A properly functioning system is nothing but positive for a street-driven car. Generally without it, when you shut the car off on a hot day, the fuel boils out of the bowl and into the intake flooding the car and emptying the bowl. You go to restart it after a 20 min hot-soak and you have to crank it like crazy which is tough on the starter, battery, ignition switch, etc. as well as embarrassing:mad: As ethanol content in fuel increases (E15 in most states now), it could be more of an issue.

People remove them for a variety of reasons: esthetics, to save the weight of it, to improve access, they mistakenly think the EPA made Fiat put it on for emissions or they think it kills the battery.

If you decide to take it off, people tend to end-up employing counter-measures to address the issues created by removing it. Deleting the rain tray from the engine cover (which has its own cons) and carving out the side scoops to let more air in seem to be fix for it. Might want to consider those options if you still want to remove it.
 
I agree with Paul and admire his restraint in answering the question. As stated many people remove it. But for some of us at least it serves an extremely important function. I would never purchase an X 1/9 that had the hot soak fan deleted. Others, perhaps owing to the intermittent way they use their X, don't miss it. I have a thread on here somewhere where I measured the temperature of the carburetor base as a function of time with the fan running. But here is the plot. I even fitted the equation for a mid-90F day. The decrease is dramatic.
cooling_fan_Tdrop.jpg
 
Good question. And now you have made more work for me. Hopefully I can do that experiment this summer. But qualitatively speaking, sometimes the fan kicks back on a few minutes later. Sometimes even twice during cool-down. So without it you can probably guess that the high temperatures stay high a lot longer. So another experiment would be to track the temperature after the fan shuts off. It must rise again to around 155 before descending again.
 
I've had a couple cars with electric cooling fans on the radiator that were wired to allow run-on after the ignition was shut off. The temp sensor was the controlling factor for how long they ran. And as you say, at times they would run awhile, shut off, then a bit later run again as temps went up and down. I think a combination of temp and time would be best; allow the fan(s) to run until it cools or until a maximum time limit is reached (to avoid draining the battery).
 
LarryC said:
I agree with Paul and admire his restraint in answering the question. As stated many people remove it. But for some of us at least it serves an extremely important function. I would never purchase an X 1/9 that had the hot soak fan deleted. Others, perhaps owing to the intermittent way they use their X, don't miss it. I have a thread on here somewhere where I measured the temperature of the carburetor base as a function of time with the fan running. But here is the plot. I even fitted the equation for a mid-90F day. The decrease is dramatic.
View attachment 10699
Click to expand...
Well now you all are just talking above my abilities to understand ....lol...good feed back tho.....I have only been apart of this forum for like a few weeks and everyone has been extremely forthcoming with helpful info...so greatly appreciated...thanks to all of you
 
The system had been removed before I purchased my X. And I did have issues with starting during warmer weather when I was running multiple errands; until I had the system restored at MW-124. And I am surprised how often the fan runs; so it appears to be worthwhile. Others have said I left the car running when it's just the carb fan running. It is not very loud; would be nice if the engine really did run that quiet.
 
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