Track forum general chit chat.

[OG Shark]

Originally Posted by slicer

I think he has had some issues with the bumper pulling away from the fender which has resulted in him installing the clips. Have you ever removed your front bumper? It's not a rigidly mounted structure. Plus the bumper itself is flexible plastic - a noodle. DB is a fast driver and obviously his setup is working for him but that certainly doesn't mean that there isn't room for improvement. This is all part of the fun... And please don't think I'm claiming to be the ultimate authority of this topic.

As a general rule you want your splitter to be rigidly mounted (along with your wing) as you want the downforce to get transmitted to the chassis to push the car down - not to the bumper to flex it to the point of pulling out of the mounts.... then to the chassis.

Yes I was actually surprised how easy the bumper comes off and how flimsy it is. A direct connection to the chassis does logically sound like it would be the most efficient way to transmit downforce. But it’s interesting that he has found a satisfactory level of front downforce with a bumper mount setup that has survived quite a few offs. Wonder if the flex has aided in that at all or if it is more to do with how far his splitter sticks out.

I will be connecting to the chassis when developing my splitter. I have a couple of things I want to try that will likely need it to be fairly rigid. Very interested in the different ways everyone goes about it - definitely helps and appreciate the feedback.

[SAMM3Y]

Originally Posted by slicer

It's only chassis mounted to on the back end where it meets the Reinforcement plate under the front sub frame. Towards the front it's mounted to the bumper - which is not rigid at that point.

The turner tray comes with two supporting braces which bolt directly to the subframe in front of the lower control arms.. I think that coupled with the extra braces the APR includes to bolt to the front bumper would make for a pretty solid surface. Not optimal and nothing I would stand on but definitely a vast improvement from bolting it to the bumper and lower sump skid plate.

[slicer]

Originally Posted by SAMM3Y

The turner tray comes with two supporting braces which bolt directly to the subframe in front of the lower control arms.. I think that coupled with the extra braces the APR includes to bolt to the front bumper would make for a pretty solid surface. Not optimal and nothing I would stand on but definitely a vast improvement from bolting it to the bumper and lower sump skid plate.

I didn't know that. Very cool! I have avoided the Turner part because of its weight. I think adds 10 to 15 lbs IIRC.

[Bartledoo]

Originally Posted by roastbeef

yea, i'm not sure. think about it backwards like this- if f1 teams had the ability to make the front aero 100% rigid with no deflection, would they do it? durability and weight aside, i would guess yes.

Actually, flexible aero was the work around for the ban on active aero, and then they banned flexi aero as well. Red bull had quite a bendy front wing.

[roastbeef]

Originally Posted by Bartledoo

Actually, flexible aero was the work around for the ban on active aero, and then they banned flexi aero as well. Red bull had quite a bendy front wing.

i'm not a close follower of F1, but what i was trying to say was- if they could do it anyway they wanted, how would it be? active and rigid? active and flexy? just flexy? just rigid? any combo of the above?

[dparm]

Originally Posted by roastbeef

i'm not a close follower of F1, but what i was trying to say was- if they could do it anyway they wanted, how would it be? active and rigid? active and flexy? just flexy? just rigid? any combo of the above?

There are rules about how much deflection the various body panels can have. Kimi was penalized for it recently because the deflection was like an extra 1mm or something.

Active aero is absolutely banned.

[M3 Number 86]

Nexen sur4 275 squared with 18x10 usual apex wheels. 12mm spacer. Tires usually clear but not these lol

[M3 Number 86]

Originally Posted by slicer

I'm not sure why that would be the case. There isn't really any difference on the front end of the car that I know of.

Good point but it could do more if it's mounted rigidly.

I really don't think a bumper mounted splitter is any more practical than a chassis mounted version. I suppose this all depends on how the splitter is mounted and the rigidity of the splitter itself. The same damage you described could occur with a bumper mounted splitter that gets wedged up and into the fluid lines. I have had multiple GT4 splitters get hung up and rip away from my bumper causing damage to the bumper itself (not to any fluid lines). While a splitter that is not mounted to the bumper in any way would not cause any damage to it. For example the GTS splitter (too small I know) is mounted to a bar that is mounted to the chassis. It doesn't have any contact with the bumper. I think this would actually be a better scenario if it rips away. A very rigid splitter has the potential to do some damage when it get's ripped off - no matter how it's mounted. Now, if the chassis mounts are done in a way that they are near fluid lines, then I can see your point. I would like to think there is a safe way to execute. For Example - an easy way to take some of the load off your bumper would be to change the splitter rods. The splitter rods running to your splitter could be mounted to the bumper support (instead of the flimsy bumper). Maybe you have already done that but it looks like it's mounted to the bumper.

Not meaning to claim to be the ultimate authority here - just partaking in some thoughtful discussion.

Chassis mounted splitter that went all the way back. One to two inches longer than Gt4 lip that was custom cut by apr for me. Also added just a few bolts that also attached to the bottom of the lip.

So you can do chassis plus to lip lol.

Didn't need those splitter rods in the front. Photo at acs going however many mph with tie doing nothing and splitter in place and not flexing.

[derbo]

Originally Posted by M3 Number 86

Nexen sur4 275 squared with 18x10 usual apex wheels. 12mm spacer. Tires usually clear but not these lol

cheater sizes lol

[bigjae1976]

I would chassis mount aero because you'll run into issues with things falling off. And if you go off track, you increase the risk of ripping more stuff off. I would imagine that there is more value in the downforce than reducing flow underneath.

If you reduce airflow, wouldn't you create drag? High pressure air will want to flow into the low pressure area under the car. You'd need some sort of vortex generator. Then the airflow under the car can be used to manage tire squirt.

Most aero guys say that you want clean airflow under the car.

But I'm not an expert by any means...

[dogbone]

Originally Posted by slicer

Good point but it could do more if it's mounted rigidly.

For me, what it boiled down to was cost and availability. Racewerkz presented the option of bumper mounting a splitter as a ready-to-go solution and claimed it worked well. The alternative of creating a more rigid setup was going to cost a LOT more money. I had never driven a splitter before and was worried I would rip it off fairly quickly. Spending a ton of money on it didn’t make sense for me.

And just to be clear, I don’t think my car is the ultimate setup or the only way to do things. What it is, is a build put together by a motorsport enthusiast. Given that I had never built a car before, I’ve learned a lot along the way. If anything I’ve learned is useful to the community here, I’m happy to share it. And I’m always eager to see/hear what others have done.

[slicer]

Originally Posted by dogbone

For me, what it boiled down to was cost and availability. Racewerkz presented the option of bumper mounting a splitter as a ready-to-go solution and claimed it worked well. The alternative of creating a more rigid setup was going to cost a LOT more money. I had never driven a splitter before and was worried I would rip it off fairly quickly. Spending a ton of money on it didn’t make sense for me.

And just to be clear, I don’t think my car is the ultimate setup or the only way to do things. What it is, is a build put together by a motorsport enthusiast. Given that I had never built a car before, I’ve learned a lot along the way. If anything I’ve learned is useful to the community here, I’m happy to share it. And I’m always eager to see/hear what others have done.

Cool - we are in the same boat - it's all about learning, developing, improving!

[StripclubDJ]

Originally Posted by M3 Number 86

Nexen sur4 275 squared with 18x10 usual apex wheels. 12mm spacer. Tires usually clear but not these lol

15mm spacer f/r get on my level brooooo
Lol

[dparm]

Took the car to Texas Track Works to get another alignment. They came heavily recommended and after chatting for a few minutes, it's clear that these guys mean business.

The alignment had slipped more than we expected in ~6 months / 6 track days / 4,500 miles. At some point I may ditch the factory eccentric bolts.

For some stupid reason, the rear toe links on the C7 are NOT adjustable. They were on the C5 and C6 which share the same basic suspension design. As a result, we couldn't dial in more rear camber without it throwing the rest of the geometry out of whack. Granatelli, AFE/Pfadt, and LG all make adjustable ones. However, the guys at TTW said that these aren't an ideal design because they don't use pinch bolts like the SPL stuff does. But...SPL doesn't make a set for the C7. TTW said they'd try and hassle SPL about this some more, especially since SPL is only 3 hours south in Austin.

Hopefully, by the time it needs another alignment, SPL will have stepped up. I guess I should've hassled Fall-Line a bit more before I moved. :-p

Anyway, here's what they dialed in.

[M3 Number 86]

Originally Posted by StripclubDJ

15mm spacer f/r get on my level brooooo
Lol

[kyippee]

On the alignment front, are there any aftermarket parts that make toe less likely to be knocked out of whack on track? Aftermarket toe arms?

[gmx]

Originally Posted by Bartledoo

Actually, flexible aero was the work around for the ban on active aero, and then they banned flexi aero as well. Red bull had quite a bendy front wing.

Their wings were creating less downforce (and thus drag) for higher loads, like what you'd experience near or close to vmax on straights.

The opposite is happening here I suspect.

[dparm]

Originally Posted by kpewpew

On the alignment front, are there any aftermarket parts that make toe less likely to be knocked out of whack on track? Aftermarket toe arms?

From what the guys at TTW told me, if it uses a pinch bolt, it's basically impossible for it to slip. That doesn't mean you shouldn't be checking alignment regularly, though.

[Shmelgy]

Originally Posted by OG Shark

What is the benefit of stanchions vs cables anyways?

I was told to go with cables because they will prevent the splitter from moving down, but allow enough flex upwards if you were to: hit a bump, go off track, need a little assistance rolling off the trailer, etc.

So it allows movement upwards without causing damage while still preventing downward flex.

[kyippee]

PS fluid spit all over my windshield through hood vent and no PS below 10mph. Boiled fluid only? Dead pump too? Anybody experience this?

[roastbeef]

Originally Posted by kpewpew

PS fluid spit all over my windshield through hood vent and no PS below 10mph. Boiled fluid only? Dead pump too? Anybody experience this?

you just put the fancy reservoir on, right? check hoses. i've heard if you try to contain it, the fluid just starts blowing through the hose seals.

[kyippee]

Originally Posted by roastbeef

you just put the fancy reservoir on, right? check hoses. i've heard if you try to contain it, the fluid just starts blowing through the hose seals.

Yea it's weird. There's still fluid in there, at the minimum level. Color doesn't look as bright green as it should... I guess I'll try just sucking out old boiled fluid and putting in fresh fluid?