33 Machine electric 818e build- Sold! Headed to China!

[Jaime]

I'm thinking of doing this:



If I add a few more degrees of movement, it should lock open under its own weight.

[RM1SepEx]

Erik, any input on this copy of your hood hinge design?

you have to twist the bracket to make the hinge point vertical, I think there is a photo in my thread, our hinges are the same in theory, I used 1/8 steel, he used 1/4 aluminum (I think) we both used a small brass shoulder bushing

[ehansen007]

Erik, any input on this copy of your hood hinge design?

Thats almost exactly what i did and i wished i would have seen this beforehand. As RM said you have to twist the end as well to compensate for the head light bucket side angle. I also made the hole as far foward as possible so very little of the nose had to duck into the opening. Good luck !

[RM1SepEx]

good point on the pivot hole location, it needs to be at the very front edge so that the hood pivots around the front edge as much as possible, that design has it so far back that it will bind the hood in the nose's fiberglass as it angles down. It would have been easier if the headlight bucket and hose had vertical edges...

[Aero STI]

Thanks for the input guys. I added a second pivot hole for the bracket that will get epoxied to the hood. This design uses a pressed in bearing. I'm going to have my friend's machine shop cut and bend everything up. They can bend just about anything, but I'm not sure this will put in the twist.



I'm using 3/16" 5052 so I think I can add the twist after the fact.

[ehansen007]

Well, I was surprised that after adding the body, the doors, and most of the sheetmetal the car went from 1700lbs to 2189lbs! More than I thought but it does all add up.







I don't know what more I'm going to on the balance side of things to even it out but she feels so good on the street and track (with a bit of bumpsteer). Jim says it will only get better as you get it setup right. I tried to move the rear wheels a bit closer to the center of the wheel well, but the rear upper trailing link just wasn't able to give me much difference. The car is pretty sweet to drive around for sure and handles great. Now it's time to do more work on the interior and possibly some body work.

[RM1SepEx]

That's pretty good weight distribution Erik!

[ehansen007]

Well this sucks. Took it out for a nice spin to the car show and now I can't get the thing into reverse. But was having a hard time down shifting from 4 to 3rd and it wouldn't stay in 5th. I've tried everything to get it into reverse. Even manually without the linkage? Think I'll have to crack the case open? I've read everything from reverse check sleeve to bent shifter fork. Ugh.

[Aero STI]

It might not be a bad idea to pick up a spare 5MT. I plan to get a spare to put an LSD in. I see them in my area regularly listed for $600-$800 in working condition and $100-$300 with broken 2nd or 3rd gear.

[Wayne Presley]

Erik, your cross weight is off. Enough to be noticeable when driving

[Frank818]

Erik, your cross weight is off. Enough to be noticeable when driving

What should be an acceptable cross and what's the behavior when it's off?

I do not know anyone with 4 scales like this, I am even unsure I know someone with a 1 scale. Is this a problem for street?

[RM1SepEx]

http://www.stockcarracing.com/techar...your_race_car/

[Frank818]

Well that was very interesting to read. But to me 52% is excellent, just like front 48% and rear 52%. So I am not sure why Wayne says 2% over 50 is off. What is off? Is 1% over 50 off too?

Then if I don't get my car balanced with a $1000 scale set, I might be screwed, if I understand.

[Wayne Presley]

49.9% is excellent, 50.1% is excellent. You will feel that 2 % on the track or under braking

[Frank818]

Jesus that's pretty spot on to 50-50.
Well I guess I have to find a way to balance my car. Especially those not doing it like FFR or using a totally different engine.
Tnx Wayne and tnx to Erik as well.

[ehansen007]

Need to get that tranny fixed first. Then I'll work on the cross weight.

[JeromeS13]

Well this sucks. Took it out for a nice spin to the car show and now I can't get the thing into reverse. But was having a hard time down shifting from 4 to 3rd and it wouldn't stay in 5th. I've tried everything to get it into reverse. Even manually without the linkage? Think I'll have to crack the case open? I've read everything from reverse check sleeve to bent shifter fork. Ugh.

When I lost reverse in mine, it was because 5th/Reverse got overheated due to low fluid. :-(

[ehansen007]

That is SUPER helpful. Thank you. I had a feeling that might be it because I did the same thing some Others did and only filled to the line. I actually thought I put too much in or that some was still left in there after draining it and I emptied it out before the Adams video shoot. That may have been enough the to screw me. Did you just replace the syncros between them? How did you fix? I've rebuilt a T5 a couple of times so I have the tools. Thanks again.

[JeromeS13]

I ended up buying a transmission from a 2012 WRX.

[ehansen007]

I may take a crack at redoing this transmission. The rebuild kit is 400 and you end up with something you know is refurbed and not a question mark. It's a lot of work I know but I don't want to go through this again after buying another used tranny. As long as the gears are not thrashed and nothing's bent, it's just syncros, blockers, and bearings!

[Speedy G]

I'm sure you're not wrong, but how can porsche pull off a 60:40 weight distribution and be known for excellent braking? How do they do that, anybody? I read somewhere something about wheel width having something to do that as well.

49.9% is excellent, 50.1% is excellent. You will feel that 2 % on the track or under braking

Eric, very interesting about the weight of the fibreglass stuff. I wonder how much weight could be saved with carbon fibre panels.

[ehansen007]

Demons out!!

[C.Plavan]

I'm sure you're not wrong, but how can porsche pull off a 60:40 weight distribution and be known for excellent braking? How do they do that, anybody? I read somewhere something about wheel width having something to do that as well.



Eric, very interesting about the weight of the fibreglass stuff. I wonder how much weight could be saved with carbon fibre panels.

Wayne was referencing cross weight, not front/rear distribution.

[ehansen007]

I'm sure you're not wrong, but how can porsche pull off a 60:40 weight distribution and be known for excellent braking? How do they do that, anybody? I read somewhere something about wheel width having something to do that as well.



Eric, very interesting about the weight of the fibreglass stuff. I wonder how much weight could be saved with carbon fibre panels.

I imagine it would be equivalent to stacks of $20's. Many stacks.

[Boog]

Its crazy to see the business end of the pressure plate just kind of floating there due to the lack of an ICE. Very cool.

[Wayne Presley]

I'm sure you're not wrong, but how can porsche pull off a 60:40 weight distribution and be known for excellent braking? How do they do that, anybody? I read somewhere something about wheel width having something to do that as well.



Eric, very interesting about the weight of the fibreglass stuff. I wonder how much weight could be saved with carbon fibre panels.

I was talking about cross weights being as close to 50/50 as possible. And for braking, the Lotus Elise that I race has 35/65 fr/rr bias and routinely outbrake everything with 205/50/16 fr and 225/45/17 rear tires.

[ehansen007]

Thanks Wayne, how would I change the cross weighting other than moving weight around? Suspension? And remember guys, I'm not sitting in the car either. So that's 185lbs not being accounted for. It would be even more off than that. Still it handles amazing and I'll continue to tune it after I get the important stuff done to make it street legal. Right now I've done a ton of research and can't find anything or anyone that knows what would cause reverse to completely disappear.

[Frank818]

Changing ride height at each corner will change your cross weight. Must be done after your L-R and F-R distributions are tweaked to your likings.

[Boog]

Changing ride height at each corner will change your cross weight. Must be done after your L-R and F-R distributions are tweaked to your likings.

Wouldn't that then change the L-R and F-R ratios you just setup?

In the past I've just had a shop setup the chassis for other vehicles, but I would like to take 'full ownership' so to speak. I'm curious about the complete setup order for alignment and the different balancing steps. It seems like adjustment of either will effect the other.

[Frank818]

It wouldn't change the LR and FR ratios. Now I can't explain why that yet, as I am still learning. I'm sure some gurus can take over, otherwise once I find out, I'll let you know.

[Frank818]

Once static weight percentages are set, work on cross-weight percentages.
You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight.
Changing the ride height at any corner will change the cross-weight percentage.
If you raise the ride height at a given corner (put a turn in or add a round of wedge), the weight on that corner will increase, as will the weight on the diagonally opposite corner. The other two corners will lose weight.
If you lower the ride height at a given corner, that corner will lose weight as will the diagonally opposite corner. The other two corners will gain weight. This will not change the left-side or rear weight percentages.
To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. For example, if your initial setup is 52 percent cross-weight, and you want 50 percent cross-weight, lowering the right front or left rear corner will decrease cross-weight percentage. You could also raise the left front or right rear ride heights to do the same thing.

http://grassrootsmotorsports.com/art...orner-weights/


I'm still not sure I follow up 100%.

[Boog]

Thanks for the link. I've read it in the past but its always a good re-read.

It's easy enough to go with their experience, but I'm still curious as to why adjusting the spring seat at both left hand wheels would not change the right:left ratio.

[Jaime]

How much would it actually tip the car? If you went nuts on the springs on one side, you might get it to roll by one degree. One degree moves the center of gravity .02 inches sideways for every inch the CG is above (or below) the roll axis. In the most extreme case I can imagine, the CG might be 10 inches above the roll axis, meaning the CG will move 0.2 inches. That will transfer 1.5% of the cars weight to one side, or about 27 pounds. To summarize, you'd need a really top-heavy car with a high CG, and you'd need to adjust the preload to the extreme of one side all the way up and the other side all the way down just to move 30 pounds.

Cross weight is a suspension setup measurement. Static weight distribution is what you guys keep thinking about.

[Boog]

How much would it actually tip the car? If you went nuts on the springs on one side, you might get it to roll by one degree. One degree moves the center of gravity .02 inches sideways for every inch the CG is above (or below) the roll axis. In the most extreme case I can imagine, the CG might be 10 inches above the roll axis, meaning the CG will move 0.2 inches. That will transfer 1.5% of the cars weight to one side, or about 27 pounds. To summarize, you'd need a really top-heavy car with a high CG, and you'd need to adjust the preload to the extreme of one side all the way up and the other side all the way down just to move 30 pounds.

Cross weight is a suspension setup measurement. Static weight distribution is what you guys keep thinking about.

Ok, that makes a lot of sense.

[Wayne Presley]

Here's a quick run through on setting up.
1: set the tire pressures (on race cars set it to your hot pressures)
2: set front and rear ride height
3: check corner weights
4: adjust spring collars to get even cross weights
5: recheck ride height
6: align the car
7: recheck corner weights and adjust cross weights if necessary

Example
LF 375 RF 340
LR 610 RR 635
Now if you have exactly the same ride height side to side on the front and rear, then go tighter on the spring perches on the RF and LR evenly. The reason I go up is because the springs tend to settle. But if the LF is a little high, loosen that collar. After you adjust the collars, recheck ride height.

[Wayne Presley]

Static weight is the R vs L and F vs R. The only way to adjust those once the cross weight is set is to move stuff on the chassis.

[Bob_n_Cincy]

Hi Wayne,
Thanks for your advice.
If auto crossing and track days 818s. Would you do the balance with equivalent weight in the driver's seat?
Bob

[Frank818]

5: recheck ride height

Wayne, if you set cross weights with some ride height adjust and then check ride height, the ride height will obviously has changed and there is nothing you can do to adjust it again since it would change the crosses, no?

[Wayne Presley]

Hi Wayne,
Thanks for your advice.
If auto crossing and track days 818s. Would you do the balance with equivalent weight in the driver's seat?
Bob

On most cars, you will need a suitable CTD to place in the seat to simulate your tail being in the seat. On these exact cars you sit so close to the F to R CG that it doesn't affect the cross much at all. I see as little as .1% with me in vs out.

Wayne, if you set cross weights with some ride height adjust and then check ride height, the ride height will obviously has changed and there is nothing you can do to adjust it again since it would change the crosses, no?

True but typically you are talking about a 1/16" or less ride height difference side to side. I'll take that difference to get even cross weights every time.

Make sure you either have roll off pads to move the car off and on the scales after adjusting the springs or put two layers of trash bags between the tires and scales. Then push down on the front and rear of the car to even out the ride stance. The tires can get side loaded from jacking up and mess with your readings if you don't.

[Bob_n_Cincy]

On most cars, you will need a suitable CTD to place in the seat to simulate your tail being in the seat.

OK, I'll bite. What is a CTD?
Best I could come up with is " Cheaper Than Dirt"
Bob