Shock suggestions for extra weight in electric 911?

[PeteStorm]

Ok, now please no death threats but I'm converting a 1977 911 to an electric vehicle so I'll probably be netting about 150lbs in the rear and about 425lbs in the front.

Any suggestions for shocks choices or changes to suspension setup? I'd really like to maintain the 911 ride characteristics but will the extra weight I'm concerned I might have to go with an air suspension!

[PeteStorm]

Oh yeah, it'll be running stock 993 turbo turbo twists as well since it'll have a 993 body kit on it if that makes a difference.

[911pcars]

At least the F-R balance will be more even.

You'll have to change the spring rate to compensate for the added weight and revalved shocks to control the new spring rate. Not sure of specific recommendations though. You may have to refer to some spring calculations to maintain the same ride height.

Any specific details you'd like to share regarding the running gear?

Sherwood

[Cory M]

My suggestion is to figure out your cornerweights and spring rates, then make a call to Bilstein Motorsports in Poway CA and have them revalve a set for your application.

[PeteStorm]

Originally posted by 911pcars
At least the F-R balance will be more even.

You'll have to change the spring rate to compensate for the added weight and revalved shocks to control the new spring rate. Not sure of specific recommendations though. You may have to refer to some spring calculations to maintain the same ride height.

Any specific details you'd like to share regarding the running gear?

Sherwood

Nothing unusual really as it'll maintain the 915 transmission and a beefed up clutch to handle the high torque of the electric motor (11" Kostov.) Sounds like 1st and 2nd gear will be useless except for smoking the tires.

[TRE Cup]

23 mm front torsions/ 27-28 mm rear torsions and with the revalved shocks, the car will ride pretty nicely

[Monza_dh]

Keep posting updates. I just read about the drag racing group from Portland, OR in Car/Driver that drag electics. Huge torque but no noise!

I'd love to see how you are doing this in a P-car.

[PeteStorm]

Originally posted by Monza_dh
Keep posting updates. I just read about the drag racing group from Portland, OR in Car/Driver that drag electics. Huge torque but no noise!

I'd love to see how you are doing this in a P-car.

Well, I wouldn't say it's me doing it. While I'm pretty handy, on this one I'm really only giving specs and going into debt over it! I'll certainly be tweaking it once it done and upgrading later.

Oh yeah, you must've seen White Zombie in the May Car and Driver. Super fast. Checkout his buddy on an electric motorcycle from this weekend: http://www.youtube.com/watch?v=GDHJNG2PngQ

[Elu]

subscribed....

I would like to see pictures and updates! Awesome! I've thought about this many times...

[PeteStorm]

Originally posted by Elu
subscribed....

I would like to see pictures and updates! Awesome! I've thought about this many times...

There are many budgets from $7K-$8K do-it-yourself with your own donor car low power/low acceleration project to the $50K-$100K sports car with tons of power. A good place to start to understand what's involved is with this (a little dated) book called "Convert It!" by Micheal Brown. His company makes entry level kits (http://www.electroauto.com/). If you want to be overwhelmed checkout the EV list at http://tech.groups.yahoo.com/group/ev/ White Zombie and Killacycle guys post there all the time.

As with anything, if you want the cool technology, you're gonna pay for it. But, I assume you know that since you're on a Porsche forum!

[EarlyPorsche]

Bilstein offers a revalving service for their shocks. They rebuild and tune them based on a weight you give them. Here is a link, its pretty cheap. Buy some used Bilsteins and send them in with your specifications. Torsions you can just buy off this site.

http://www.bilstein.com/services.php?PHPSESSID=275d353b6a52807ade9b7b60afa e3387

[PeteStorm]

Sweet! Thanks everyone for all the responses. This project should be coming to an end in the next month or so and I'll upload some pics and figure out performance specs for ya.

[HarryD]

Read the Saga here: http://www.ztac.net/porsche.htm

ymmv

[PeteStorm]

Originally posted by HarryD
Read the Saga here: http://www.ztac.net/porsche.htm

ymmv

So nice to know there are other electric 911 nerds out there. My system is 192V with a 1000amp controller and Lead AGM sealed batteries. Basically just more modern electronics, more powerful version of this one.

[duke3282]

Thats really cool, I am planning to build an electric car at some point. What is your maximum range going to be per charge. I dont know much about it but why are you using lead batteries instead of some of the newer lithium ion or lithium polymer batteries that are available.

[PeteStorm]

Originally posted by duke3282
Thats really cool, I am planning to build an electric car at some point. What is your maximum range going to be per charge. I dont know much about it but why are you using lead batteries instead of some of the newer lithium ion or lithium polymer batteries that are available.

Total guess, but if I drive like a freak around 40 miles, mellow probably 60 miles or more. Of course speed changes all of that as this is just a guess until I get it on the road. Suspect something under 200wh/mile for average consumption.

Lithium/polymers are really expensive (but yes, lighter) and complex battery management systems are required and expensive in their own right. Using the Odyssey PC1500s (http://www.odysseyfactory.com/) that are pretty much best leads you can use with lightbulb battery management system from Lee Hart (Zener diode thingy.)

Plan is to use up this battery pack in the next few years and the replacement pack with be Li-whatever type that's proven and cheaper by then.

My turbo twist wheels came in today! So excited! If I get pics I'll post. Love how the paint came out too.

[cgarr]

Are we signing up charter members to Gruppe E yet?? Great project!

[PeteStorm]

Originally posted by cgarr
Are we signing up charter members to Gruppe E yet?? Great project!

Man, now that would be cool. Hee hee. We can even get custom "Gruppe E" license plate frames made.

[PeteStorm]

How about this:

[jess p]

IF TOU PLACE TO PUT THE BATTERIES IN THE FRONT THEN YOU WILL NEED HEAVIER SHOCKS IN THE FRONT.