Formula SAE Build Thread! Road Warrior 11

In reply to GameboyRMH:

This car ran last season with 3-5 inches thick of foam padding around the shoulders for ergonomics, but we sit cheeks on carbon.

In reply to Apexcarver:

I'd love to see a titanium/carbon laden car up close. Our intakes have been an issue in the past, hoping to get something with good torque across the range. 91hp would be pretty lively in our car.

We don't have a CNC lathe either, just a lot of late nights. I find late nights are cheaper. I'd love to run carbon control arms and pushrods, just don't have the composites experience to do so.

Aero has been designed for the past 2? cars, but never made it on for cost report and actual cost reasons. Our 2014 may be getting a aero kit soon to give us practice making wings. Our last car could run with aero cars without wings, so once we go aero... skys the limit.

I wish our business team was good, its pretty much me and a few others working hard for sponsors these days, wish I was 95 lb for accel!

In reply to BA5:

We have good peak power, but really bad delivery. Torque peaks, falls off, and peaks again, not sure why? Your problem sounds better than our solution.

You probably have a resonance issue either in the box or the runners. Can you build runner extensions to move the box out and see how it changes it? Modeling would be more scientific but sometimes when you don't know exactly what's going on you have to experiment.

Are we talking rpm dependent or does it do the on-off-on thing every time you step on the gas? Two very different issues there.

In reply to ¯_(ツ)_/¯:

No, it is definitely RPM dependent. Peaks at 6500ish RPM, falls off at 7000-8000, and re-peaks near redline. Feels like a turbo reaching boost, it is extremely noticeable every time you accelerate at the same RPM.

In reply to mazdeuce:

We could do so and have had luck doing so with aluminum runners, but hard to justify with a multi-thousand dollar 3D printed intake.

Our intake was moreso a long runner tube design made of carbon with a small plenum volume as the (whats the term? reverse collector?) that fed the outlet of the restrictor nozzle divergent zone.

We were in design phase for a variable plenum volume design. Had one that opened additional chamber volume in prototype and and infinitely variable one in design phase. No idea what ever came of it though.

Was the guy who designed it targeting a certain RPM for peak torque? I've seen some pretty awesome adjustable plenum stuff from other teams before, but if the designer still has his model you can probably make a pretty good educated guess of what to change to at least move that dip around.

EDIT: "Not making it run like poop" seems like a good justification to me!

EDIT EDIT: If you're driving it well, does it ever fall into that low area or does it stay in the sweet spot?

In reply to ¯_(ツ)_/¯:

Not sure about your question, I'm under chassis and was not involved with the design of this intake. The car runs reasonably well, just has very strange power delivery due to that flat-spot in torque. And the gearing makes it very challenging to keep it in power, as you are either limited to the lower or upper half of the power band and shifting puts you on the opposite side of that dip.

If you're not gearing limited yet you could play with the sprocket (or rear tire) sizes to keep it in its' happy place.

In reply to ¯_(ツ)_/¯:

I know it has been discussed and sprocket size has been optimized for the unique powerband, but the car still behaves oddly. I'm not a good enough driver to say its the car's fault or my own, but it certainly makes corner exits a gamble.

Great work, WSU has come a long way over the past few years. 10th at Lincoln is a big victory.

I was on Oakland's team a while back and spent a ton of time (simulation and dyno) getting a linear powerband. It paid off though. 80hp and 80% of peak torque from 5500-12000. If you have some logs from comp take a look at histogram of pedal position and rpm band frequency. It can be a real eye opener for where resources are best spent on the powertrain side.

Keep us posted on the new car. I really miss the FSAE shenanigans.

RXBeetle wrote: Keep us posted on the new car. I really miss the FSAE shenanigans.

I work in automotive engineering and I very much miss those days too. Looking very hard at doing a DM locost to scratch that old itch.

In reply to RXBeetle:

Thank you! We've done some analysis of datalogger files from competition and I believe that is being accounted for in induction design this year.

Unfortunately I can't post full car design until our unveiling in December, but I'll get everything I can up here for everyone's enjoyment.

In reply to Apexcarver:

Go for it! I can't imagine going to this school without involvement with SAE, its taught me so much and given me so many opportunities. Who do you work for?

In reply to whiskey_business:

My employer is a bit sticky about stating it in a public forum.

I will say that FSAE is perhaps one of the biggest resume boosts that you can do if you want to get into the automotive realm though. (that and internships/co-ops)

Apexcarver wrote:

RXBeetle wrote: Keep us posted on the new car. I really miss the FSAE shenanigans.

I work in automotive engineering and I very much miss those days too. Looking very hard at doing a DM locost to scratch that old itch.

Automotive engineering here as well. My work is riddled with FSAE alum.

In reply to Apexcarver:

So I have heard, and hope to experience firsthand!

In reply to RXBeetle:

Hoping to become one soon.

UIUC FSAE alum here. Don't work automotive but am building a Dmod car to scratch the itch. Did chassis/suspension/vehicle integration on our car way back in 04-05.

You graduating soon Whiskey?

Design engineering here.

I did FSAE BAJA myself.

Learned to not be involved in automotive when I co oped at Bosch so.. . yeah.

In reply to Apexcarver:

Next spring, with any luck.

In reply to nocones:

I'll have to check out your build thread, I love FSAE but think the crazier solo builds are awesome.