Hello! 2017 Cruze Hatch

[HatchBatch]

Hi Everyone!

I have been reading through tons of threads here the last few weeks as I finally got the bug to see how far I can push my Cruze's FE. I am looking for that balance between getting better FE, but still having fun every now and again, all while retaining its practicality and comfort.

Any other Gen 2 Cruze hatch owners here that could give me some pointers? I didn't find much when searching, the Gen 2 has been forgotten already it seems but they are solid cars that ride very comfortably.

Interestingly, I have followed a lot of the tips and driving methods used here through out my life (DWL, planning lane changes and assessing traffic flow to keep my speed constant, getting situated before starting the car to minimize idling, limiting A/C, limiting heater until car is warmed up, timing green lights, using big buffers to cars in front etc.), but I have never taken it to the logical conclusions that I have been reading here (DWB, EOC, P&G).

I have also really taken to aerodynamics for vehicles in general lately, so I look forward to experimenting with coroplast etc.

That said, my background is mostly from drag racing (some autocrossing), and until those cars are going really fast they tend to not think about aero much over in that world (though they should). So I know I won't be eking the best possible FE every tank since I will be doing spirited driving occasionally. I have done some modifications for increased HP (e85 capable tune, wastegate, improved BPV) so the car is much more on the sporty side when I hit the throttle and I know it will limit my overall FE gains, but I know if I stay out of boost I should be able to minimize those negatives.

The car itself is a 2017 Cruze Hatch, LT/RS. I had to hunt for a while to find a 6spd manual, but to my luck it also had manual seats, no seat heaters, no premium audio, no premium wide wheels or watts link rear. so its about as light as a Gen 2 Hatch can be other than the RS bumpers, foglights and spoiler. Problem is I suspect the RS styling (though appreciated) is probably not the best for aero. Between the big grill opening and the large spoiler I think there are easy FE gains to be had.

My initial thoughts are partial grill block, maybe air dam (though they come with a decent air dam already), partial belly pan, perhaps wheel covers, maybe rear spoiler removal (I won't be doing a kamback or boattail even though I know they really help).I dont plan on lowering it either as I really like the ride quality and pot whole worthiness. Same goes for LRRs, not looking at those as I like to do other types of driving requiring more grip occasionally. I do make sure to keep the tire pressure up. Passenger side mirror delete may happen down the road (fun fact, I have owned more than one 60's car with no side mirror and never had an issue, but those had better visibility). I don't think I'll go to quite the extent of alternator deletes or engine kill switches as this late model car has a number of computers that would not like that.

One last note, I LOVE data and good experiments, so I really enjoy what I read here with controlling environments, ABA's, tuft testing. I plan to conduct some coast down testing and possibly tuft testing as I go. But in general I have no free time these days and (luckily) have not had to drive my car much lately, downside is these mods and tests will take a long time get completed.

Sorry for the long post, glad to be here!

[HatchBatch]

Couple of pics of the car, no exterior modifications yet.

[freebeard]

Welcome.

Not a lot of that old low hanging fruit?

Maybe you could trim the ends of the spoiler to make it more of a Kammback. The air dam appears to have splitters that could be extended forward. I can't tell from the pic and angle, is the air dam extending below the splitters lower than an hypothetical bellypan? Then it could have a central notch to provide a jet down the centerline.

[HatchBatch]

Thanks, I’ll try to get a better picture of the front air dam soon as I have an oil change planned. Then I can also try to assess the belly pan potential a little more. I do agree that GM seems to have done a decent job with aero, the headlights are largely sealed tight to the fascia and hood, the factory air dam looks reasonably useful. The big RS grille seems like overkill from a cooling perspective though. I am thinking of blocking the majority/all of the main black grill, as there is stil a small opening at the bottom and the other grill piece by the hood line.

And interesting thought on the spoiler, I don’t think I want to chop up the stock unit yet, but I may keep a kammback in the back of my head. My fear is that just deleting the spoiler alone could cause more issues, if the spoiler is acting as a cleaner separation of the air flow from the roof. Even lower trim Cruze hatch backs have a small spoiler here, that why I think it may have that function.

One way to find out, test! Just gotta organize a plan and figure out when I have time for these things.

[freebeard]

I'm thinking of the splitters on the Singer Rally Concept.


i

These could be toned down, but anything forward of the nose becomes a bumper guard.

[HatchBatch]

First, great selection on image for show your point, those Singer, Porsche rally cars, great stuff!

I found a breakout image of the stock airdam on the internet. The dam itself is a flat piece that goes down, but there is that lip, almost like a spoiler, that could be like the splitters you are showing. Its an interesting thought to ponder how I could extend those while keeping them structurally sound and not look too poorly made (my fab aero skills are not quite at the level of others on this forum yet).

[freebeard]

The lower piece has those interesting votex generators.

The upper piece looks more complicated than simple tabs. Obtain a second part, make a female mold and overmold it. Then it becomes a bolt-on part.

[HatchBatch]

Good catch on those little bits being vortex generators. I don’t think I am quite to mold making but I like the idea.

I also got a chance to look under the car a bit, and there is a 2 piece partial belly pan for the engine bay, the center is open for the exhaust. I eventually would like to make something to fill that gap.

Also, the stock dam does seem to be low enough to cover the lowest points of the suspension, may not be a huge gain to make my own just yet until I have the time to really revamp a number of things.

[ME_Andy]

Nice car, the hatchback is very rare. Btw what kind of mpg do you get?

[ME_Andy]

Btw personally I would start with a lithium battery to drop weight before any aero mods.