Torchandregdoc
Goblin Guru
Sorry for my ignorance, but does a belly pan make enough difference to warrant the work? I mean, I guess it does, and that's why you did it. Can you feel the difference, or is it something that only the clock can see?
Chris’s 2007 SS/SC track frame build for autocross
- Thread starter ccannx
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ccannx
Goblin Guru
Not sure what it was, Alan with ZZP told me about it because my MAF wasn't working properly. He said it was tied to the ground for the intercooler pump but my intercooler pump was working fine. Most likely something I did in the wiring. Funny thing is I had checked the fuse before and it didn't look blown, it actually blew out on the side nearer one of the pins and not in the middle so I never knew it was blown the entire time I ran the car with the supercharger.
Torchandregdoc
Goblin Guru
I've checked all my fuses, both with a test light and visually, and don't have any that are blown. I do have a few that are dead on both sides though. DF did my wiring, so I'm not a familiar with what all was cut out as I should be. I've researched them out and decided that non of them would be my problem, but your post has me wondering again. The HHR fuse box isn't laid out like the Cobalt, so I can just compare apples to apples.
ccannx
Goblin Guru
Yes it is noticeable. Imagine a 15x6 foot long flat sheet of OSB board going 60mph down the interstate if you take the front of it and dip it about 1/2 to an inch lower than the rear the air that gets under the front will have to expand and create a negative air pressure greater and greater as it travels the distance of the sheet towards the rear.
ccannx
Goblin Guru
Is yours an LSJ ? Have you checked all vacuum possibilities ? I had a terrible Vac leak at my Bypass valve. Can you rearrange your intake pipe to the original length just to see if it runs better ? Alan with ZZP said I had to run the pipe that came with the kit for my MAF to run well. I guess it really does make a big difference.
Torchandregdoc
Goblin Guru
I understand 80's era downforce, so I see where your going, but they had huge skirts to contain the vacuum. This belly pan aero has been on my mind. I'm getting ready to build a custom wheelchair accessible toyhauler and have had multiple people tell me to make sure and put a pan on it for aero, and I just wasn't aware that without sideskirts, that ground affect mattered that much.
Torchandregdoc
Goblin Guru
I have an Lnf. Most of the lines are new and it runs really quite well with the MAF unplugged. I haven't seen any vacuum leaks, but I just did a very rudimentary rest with a can of starting fluid. I have considered putting the original maf tube on just to see how it works.
Waterdriver
Goblin Guru
The fast moving air traveling under the shoots up after the rear firewall, creating very turbulent, tumbling air in the engine bay area. Working like a parachute.
Having a windscreen creates a low pressure area and will aid in that air traveling from the engine bay into the passenger compartment. I think George confirmed this in his posts.
In riding in another Goblin, I could smell the exhaust when driving at 35mph and under confirming this airflow theory.
Even an unsealed flat floor extended all the way back, will aid with airflow.
If adding a floor, be wary of the shifter cables by the exhaust and use heat reflective shielding as George had noted.
Desert Sasqwatch
Goblin Guru
Another area is the open floor under the battery area between the front suspension attachment frame. Air coming under the car will try to fill that area, coming up from underneath (thus the reason the DF heat exchanger can be mounted there and get airflow), but it creates a lot drag and lift under the nose of the already very light front end. Enclosing this opening with a floor extension helps to cure most of this, but the incoming (and outgoing) air from the heat exchanger will need to be reworked.
Torchandregdoc
Goblin Guru
Interesting stuff. We are trying to get registered in the next week or two and then I'll do some experimenting with this.
Torchandregdoc
Goblin Guru
Now you're talkin'. Does it work as expected?
ccannx
Goblin Guru
Yes but car felt very loose last autocross.I had not aligned it correctly and had toe out in the rear causing off throttle to be very scary. On the fly stiffening up the front swaybar helped. Bringing the load point inward I upped my spring rate from 180lbs to 300.
Torchandregdoc
Goblin Guru
And, do you think that's to stiff now possibly, and that's why the front roll bar made a difference? Front and rear roll rate was upset by the new rear spring rate? It doesn't seam like they moved that far inward.
Obviously you have a huge amount camber adjustment now, that may take some testing to get figured out.
I'm so new to set up, I have no business asking these questions, but just trying to learn.
Obviously you have a huge amount camber adjustment now, that may take some testing to get figured out.
I'm so new to set up, I have no business asking these questions, but just trying to learn.
Torchandregdoc
Goblin Guru
Is that about the amount of squat that you get in the rear? You are running 150's if I remember right?
ccannx
Goblin Guru
As George said it is how the camber changes in relation to suspension travel. I have been trying many spring rates last rate was a 10" 140/250. I moved from that as a suggestion from someone who's knows better lol.
1.3 degrees over 2 inches
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