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 Post subject: Front mounted fuel tank
PostPosted: November 21, 2013, 7:14 pm 
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Looking at my car, I feel like it is going to be rear weight biased and would like to make it close to 50:50 or 52F:48R would be perfect.
I was thinking about placing the fuel cell being the radiator and in front of the engine. This in my opinion has pros and cons.

Pros,

Better weight distribution behind front wheels and lower than on the rear (in my car).
Closer to the engine
Farther away from me
More protection from impact, Most likely I would have to hit someone to damage the fuel cell rather and someone running into the back or me.
One less thing to run through the transmission tunnel.
Can have a nice boot/trunk area for the groceries

Cons,
Heat from radiator and engine
Reduced airflow to cool the engine and transmission
Lots going on in a small space at the front of the car.

I think there is plenty of room to fit a reasonable size tank into the space and i would just make a simple shelf above/behind the steering rack. If required I could make a heat shielded box to protect from engine heat.

What are your thoughts, I have never seen anyone do this before, I presume there is a reason for that, maybe not. Please let me know your thoughts. Anyone know if that would make it illegal according to SCCA rules.

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PostPosted: November 22, 2013, 9:17 am 
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It has been somewhat done before, and it is something I am considering. I don't know if you'll be able to get a tank between the rad and your engine, but bonjo's setup would work. He was only able to fit a 4 gallon tank under the scuttle, so maybe you'll be fine for short track events. I have thought about utilizing part of the passenger foot well and the space behind my engine (which is the right side of the engine bay) for a custom made tank of about 9 gallons.
But there are other considerations (raceral makes some very good points) in my similar thread.
My main reason for considering such a setup, is weight distribution. With a light engine and a heavy axle, it only makes sense, but it will require a lot of fabricating.

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PostPosted: November 22, 2013, 11:45 am 
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In a front-engine car, you want as much rear weight bias as possible. It helps braking, acceleration, and if your rear tires are wider than the fronts, it offsets the static weight distribution.

Also, add to the Con list that a fuel tank at the front becomes a crush structure. If it's done, put in a real fuel cell, not a simple metal or plastic can. And, front accidents are much more common than anything else. Just sayin... check out the other thread on the crashed Stalker.

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PostPosted: November 22, 2013, 4:48 pm 
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There is plenty of room for an 8 gallon tank between the front wheels on my car the engine sits 2-3 feet behind the front wheels so space is not the issue. I do think you are right about getting a proper fuel cell with a bladder. I was also thinking about insulating the box to keep the heat down. I think I will make a cardboard mock fuel tank and take some photos.

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PostPosted: November 22, 2013, 5:40 pm 
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I think a few percent more weight on the rear wheels is a good thing for our cars. So if you could choose between 52F:48R and 48F:52R I would go with the later... That's my thinking anyway, maybe there are drawbacks to this.

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PostPosted: November 22, 2013, 6:21 pm 
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In the E Mod Autocross class there is a 50lb weight penalty for having more weight on the rear wheels. This is one one the main reasons I wish to move the weight further forward. and have a maximum of 50% on the rear wheels.

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PostPosted: November 22, 2013, 7:02 pm 
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wrightcomputing wrote:
In the E Mod Autocross class there is a 50lb weight penalty for having more weight on the rear wheels. This is one one the main reasons I wish to move the weight further forward. and have a maximum of 50% on the rear wheels.

Is this for autocross only, track only, street, are all three? If it's autocross only, I redact my point about needing a real fuel cell.

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PostPosted: November 22, 2013, 9:31 pm 
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The car is primarily for Autocross (10+ events per year), but I am going to make it street legal eventually and will do the odd track day maybe 1-3 per year depending on what deals I can find and how the car copes on track, Sebring destroys cars.

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PostPosted: November 23, 2013, 6:07 pm 
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Remember that the more effect your fuel tank position has on the center of gravity, the more the center of gravity will move as the fuel level changes.

With a front engined race car struggling to make minimum weight in a class that offers a break to cars with less rear weight bias and offering virtually unlimited engine options, there is another (more traditional) solution available for getting more weight on the front half of the car and help make minimum weight, which should also help overall competitiveness. :wink:

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PostPosted: November 23, 2013, 7:19 pm 
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wrightcomputing wrote:
The car is primarily for Autocross (10+ events per year), but I am going to make it street legal eventually and will do the odd track day maybe 1-3 per year depending on what deals I can find and how the car copes on track, Sebring destroys cars.



Are you going to try and get insurance on it if you make it street legal? If so, check with your insurance agent before you make any rash decisions; so insurance underwriters will not insure cars with tanks mounted in front of the driver (old VW Beetles notwithstanding). Something about flames blowing back on your face or something silly like that.

Tom

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PostPosted: November 23, 2013, 9:04 pm 
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Off Road SHO wrote:

If so, check with your insurance agent before you make any rash decisions; so insurance underwriters will not insure cars with tanks mounted in front of the driver (old VW Beetles notwithstanding). Something about flames blowing back on your face or something silly like that.

Tom


Hagerty never asked about fuel tank position. BTW, every Porsche with a mid or rear engine has a fuel tank forward of the humans.


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PostPosted: November 23, 2013, 11:15 pm 
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JonW wrote:
Off Road SHO wrote:

If so, check with your insurance agent before you make any rash decisions; so insurance underwriters will not insure cars with tanks mounted in front of the driver (old VW Beetles notwithstanding). Something about flames blowing back on your face or something silly like that.

Tom


Hagerty never asked about fuel tank position. BTW, every Porsche with a mid or rear engine has a fuel tank forward of the humans.

That is a very good point about Porsche's.

Here is what I am thinking about doing, the Pink box as 15"x14"x6" I easily have enough room to go to 8" deep and a few inched wider but mot much along the lines of longer as I don't want it too close to the engine and block the radiator airflow. I should be able to fit an 8 gallon tank in that space. That is probably the strongest part of the chassis too, but may be an issue in a head on collision. It should be very easy to make a mounting bracket and that will also add more rigidity to the front end.
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