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Issues with tilting an engine?

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I plan to use a WR450F engine in a Formula SAE car (a shifter cart on steroids). By tilting the engine fore and aft, I can lower the CG of the car. My question is, how much can I tilt the engine before I run into problems? When you reply, don't just say 20* without a justified explanation about why that is the maximum, or otherwise how that number was derived. I understand it is not likely that someone will know the tilt angle where problems will arise so please feel free to also comment on what problems may occur as the tilt angle is increased (e.g., low oil pressure, insufficient lubrication, blow-by).

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You didn't say which year/generation WR450 you're using. The primary difference is in the location of oil storage. Gen1 ('03-'06) is a dry sump engine using an external tank, while Gen2 ('07-'12) is also a dry sump, but uses an integral feed oil reservoir.

The first concern is over how the tilt will affect sump scavenging. Look at how the sump pickup screen is located in both engines. A fair amount of forward tilt should be tolerable in this regard. Rearward tilt beyond about 20 degrees will allow oil to collect in the trans without being scavenged. The engine is not in danger of starving until you pass something like 45 degrees, but you should avoid too much of it, nevertheless.

The next concern is how oil drain back will be affected. Too much forward tilt may cause an excess of oil to pool around the exhaust guides. Because of the way crank oil windage is controlled, too much forward tilt may lead to excessive windage on the crank by interfering with the movement of oil out of the actual crankcase to the sump.

Lastly, there is the feed concern. This pretty much would only apply to the Gen2 engine, as the Gen1 will feed in any position as long as the tank is mounted at or above the level of the pump. The Gen2 engine's oil reservoir is located in the front of the crankcase casting, and is roughly triangular/wedge shaped vertically, with a point at the bottom. An excessive tilt could lead to the oil level being too low relative to the pump.

Get a service manual and review what the cases look like, or look yours over while it's apart. You'll see what I mean.

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Thanks for the reply, that was very informative. It's no wonder you have over 31,000 posts. :smashpc:

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I didn't know what I should be looking for when I do my own testing, or if I was overlooking other details not mentioned in my first post. It makes no sense to waste time researching if my question has already been answered. The basis of all research is to build of what has already been discovered.

It goes without saying that you are able to use or otherwise complete a process without fully understanding it. Obviously, you know that when you turn the steering wheel in a car, the force provided through the tires are the reason you turn; however, I can guarantee that you do not understand the mechanisms that the tires are able to provide the necessary lateral forces. Allow me to simplify: everyone can use a toilet, but not everyone knows how it works.

My point is that I don't need to be a guru in all aspects in order to help build the part in question. Again, I was getting a basis for my question, after which I can continue my research to come to a final conclusion.

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I'm sorry about that, but I see FSAE as an opportunity to learn and understand things. Now what use does it have if you aren't even trying to? I know the engine isn't the most important part and most teams very much overlook it, as long as it works it'll do and never even open it.

Cars are tested on a skid pad so they may see lots of lateral g's for prolonged times and that should be considered. It shouldn't be an issue normally, but if you tilt the engine it might become one.

I'm involved in building one myself, although we've moved on to a electric car.

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I was in FSAE a long time ago and had a great time. Is it still a 600 cc limit?

It would be cool to have a DI two stroke like the snowmobile boys did.

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Dont forget that dirbikes aren't designed to take flat corners- this can make the oil slosh to one side and starve the pickup (like a long sweeping corner)

I know a lot of teams ruin engines their first time out when doing skidpad tests :smashpc:

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Cars are tested on a skid pad so they may see lots of lateral g's for prolonged times and that should be considered.

Dont forget that dirbikes aren't designed to take flat corners- this can make the oil slosh to one side and starve the pickup (like a long sweeping corner)

I know a lot of teams ruin engines their first time out when doing skidpad tests 👍

All the more reason to use an engine like the WR that employs dry sump oiling. :smashpc:

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I was in FSAE a long time ago and had a great time. Is it still a 600 cc limit?

It would be cool to have a DI two stroke like the snowmobile boys did.

Unfortunately two strokes are banned. 4 strokes maximum of 610cc are used.

In europe the main focus (top teams and money) is shifting rapidly toward full electric vehicles which is kinda sad, but also very exiting.

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No, it's not very exciting. Your goal should be to produce a fuel powered vehicle that is so much better than the electrics that they will dump the idea of electrics all together. This shouldn't be very hard to do without some serious handicaps for the electrics.

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I in-vision an external sump and a strategically located drain hole drilled in the bottom most area after tilting. You could pipe the oil from the sump to the pump through another hole made in the case. My concern would be tilting forward would possibly starve parts of the trans. Tilt to the rear would be my first look. With that thought you could potentially get away with 40 to 70 degrees of tilt.

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It's a very cool idea, but the performance level at a FSAE competition is pretty ridiculous. I think you'll find the WR450 isn't going to cut it powerwise.

We used an F4i with a ton of head work and high compression, and still weren't anywhere near the top of the engine game.

They limit the intake also, to 19mm or 20mm or something at a point ahead of the throttle body(ies) so your wr450 is going to be wheezing if you try to rev it to make up for the cc's you're down.

the big single might be a good idea, but you may have to look to Husqvara, KTM or husaberg to find a cylinder that will go all the way to 610cc's

as far as oiling, an external tank, with multiple drain points from the case is ideal. you'll probably need another pump for scavenging though, because otherwise the motor will need to be high enough to drain on it's own, and then you've lost anything you could've gained by tilting it.

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