I'm thinking of doing this:
If I add a few more degrees of movement, it should lock open under its own weight.
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I'm thinking of doing this:
If I add a few more degrees of movement, it should lock open under its own weight.
Dan
818S #17 Picked up 8/1/13 First start 11/1/13 Go Kart 3/28/14
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 !
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...
Dan
818S #17 Picked up 8/1/13 First start 11/1/13 Go Kart 3/28/14
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.
Last edited by Aero STI; 08-12-2014 at 08:26 PM.
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.
That's pretty good weight distribution Erik!
Dan
818S #17 Picked up 8/1/13 First start 11/1/13 Go Kart 3/28/14
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.
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.
Erik, your cross weight is off. Enough to be noticeable when driving
Wayne Presley www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
Dan
818S #17 Picked up 8/1/13 First start 11/1/13 Go Kart 3/28/14
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.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
49.9% is excellent, 50.1% is excellent. You will feel that 2 % on the track or under braking
Wayne Presley www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
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.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
Need to get that tranny fixed first. Then I'll work on the cross weight.
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.
I ended up buying a transmission from a 2012 WRX.
818S - #67 (SOLD IT!)
Delivered: 18 November 2013
Go Karted: 29 December 2013
Titled/Registered: 28 March 2014
Finished: NEVER!
341 hp @ 4844 RPM / 389 tq @ 3717 RPM
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!
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.
Thanks- Chad
818R-SOLD!!!- Go Karted 7/20/14/ Officially raced NASA ST2- 2/28/15
2016 Elan NP01 Prototype Racecar Chassis #20
1969 Porsche 911ST Vintage Race Car
1972 Porsche 911T (#'s matching undergoing nut & bolt resto in my garage)
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 www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
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.
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.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
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.
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.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
http://grassrootsmotorsports.com/art...orner-weights/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.
I'm still not sure I follow up 100%.
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
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.
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.
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 www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
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.
Wayne Presley www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos
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
Frank
818 chassis #181 powered by a '93 VW VR6 Turbo GT3582R
Go-karted Aug 5, 2016 - Then May 19+21, 2017
Tracked May 27/July 26, 2017
Build time before being driveable on Sep 27, 2019: over 6000h
Build Completed Winter 2021
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.
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.
Wayne Presley www.verycoolparts.com
Xterminator 705 RWHP supercharged 4.6 DOHC with twin turbos