Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

Reply
 
LinkBack Thread Tools Display Modes
Old 06-25-2014, 01:15 PM   #1
Registered User
 
Join Date: Feb 2011
Location: Sacramento
Posts: 98
AWD 950hp electric boxster

I am converting a 97 Boxster to electric, and have a set of supercaps that can deliver 950hp. This is way more than the rear tires can handle.
My thoughts were to convert the car to awd to both accelerate faster, but also because the front wheels are where the braking occurs and instead of burning up all the power as heat in the brakes, you can regenerate that power back into the supercaps, so its ready to explode all the power back out of the turn.

The issue with normal awd cars is how to get the engine power from the transmission to the front (or back), and it is a complicated heavy solution.
But for electric, I just put another motor (or two) up front for the front wheels.
Very simple and in fact, better than one big monster motor.
Note this 740hp AWD Mercedes

The question is how to do it not just relatively cheap, as in only $50,000, but actual cheap, as in $1,000, since I was told my boxster is worth $700 at the junkyard today where I picked up some parts needed for the EV conversion .

Looking at the front hubs on the boxster, there is an axle stub that can be removed and an actual axle put in. The salvage guy recommending getting a C4 axle, but my question is will the boxster rear axles fit into the front hub?

The front shocks also drop down into the way, so they would have to be shortened, and again the junk guy said get a C4 shock. These are probably more than $1,000, so I need another way. Ideas?

nimblemotorsports is offline   Reply With Quote
Old 06-25-2014, 02:27 PM   #2
Rennzenn
 
j.fro's Avatar
 
Join Date: Feb 2005
Location: Virginia
Posts: 1,356
Garage
Post deleted
__________________
Rennzenn
Jfro@rennzenn.com

Last edited by j.fro; 06-25-2014 at 02:32 PM.
j.fro is offline   Reply With Quote
Old 06-25-2014, 05:34 PM   #3
Beginner
 
Jamesp's Avatar
 
Join Date: Mar 2013
Location: Houston
Posts: 1,659
Garage
I would be very interested to see your plans for this. If you start a post in the DIY section I will subscribe to it!
__________________
2003 S manual
Jamesp is offline   Reply With Quote
Old 06-25-2014, 09:38 PM   #4
Registered User
 
nieuwhzn's Avatar
 
Join Date: Nov 2010
Location: Long Island, NY
Posts: 296
Garage
And what would be the purpose of a 950HP Boxster?

Converting to AWD just to get that 950HP on the road doesn't sound like the smartest use of the platform. You probably also have to start weighting it down with bricks to keep it planted.
Why not first start with driving the rear wheels only and go for 400HP and see what happens?
nieuwhzn is offline   Reply With Quote
Old 06-25-2014, 10:28 PM   #5
Custom User Title Here
 
particlewave's Avatar
 
Join Date: Mar 2012
Location: WA
Posts: 6,087
Garage
950 on paper...

The regenerative braking is a must, along with differential and traction control (would be the same thing). Easy to do using feedback with the electric motors.
This would also prevent any wheel spin, which is just lost energy. The result being absolute maximum acceleration for the platform.
particlewave is offline   Reply With Quote
Old 07-08-2014, 01:45 PM   #6
Registered User
 
Join Date: Feb 2011
Location: Sacramento
Posts: 98
So I gather no one has ever pulled the tone ring out of the front hub
and checked if a rear axle would fit? I did not remove it because it requires removing the shock, but unbolted it and measured what I could and it the splines are the same, the tone ring looks the same size, so that is good sign.

What shock/strut is short enough? Honda Accord?
I'm going to measure the rear strut later today.

Any suggestions on removing the gas tank? There is another EV boxster, and he had hell getting it out, ended up just chipping it out with a sawzall, must be a better way?

I also need to do something about the power steering. Was thinking of using a prius electric rack, but it is rear steer, boxster is front steer. There is always an electric pump, but don't like that at all, no fluids, just current, is the best way.
How tough will it be without the power steering?

I'm guessing the car will be about 500lbs lighter in autocross trim with 60 seconds of juice on board.

Also while I'm posting, been thinking of redoing the center console to put the supercaps inside the 'tunnel'. I assume the tunnel is a structural part of the car,
so it will need to be rebuilt with some strength, right?

nimblemotorsports is offline   Reply With Quote
Old 07-18-2014, 09:49 PM   #7
Registered User
 
Join Date: Feb 2011
Location: Sacramento
Posts: 98
So I took the car for a drive today. Not with 950hp, but about 5 hp.
The manual steering is no problem at all.
I looked at the shocks, and should be able to use the rear shocks in the front with some mild adjustments.
Attached Images
   
nimblemotorsports is offline   Reply With Quote
Old 07-20-2014, 10:53 PM   #8
Registered User
 
Pdwight's Avatar
 
Join Date: May 2013
Location: North Alabama
Posts: 2,079
Tag

I want to follow this project
Pdwight is offline   Reply With Quote
Old 07-21-2014, 10:19 AM   #9
Moderator
 
Join Date: Feb 2012
Location: DFW
Posts: 782
Garage
Very interesting! Nimble, would you consider getting 275 rear tires, or 285 (rolled fenders)? It would be simpler having it RWD than AWD. What kind of torque are you expecting to get?
Kenny Boxster is offline   Reply With Quote
Old 07-21-2014, 03:31 PM   #10
Registered User
 
Nine8Six's Avatar
 
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,216
Subscribed. Not that I would ever plan moving to a similar power system but very interesting to see. Thanks for putting this up for us mate.

Out of curiosity... what is heavier. An 3.2 engine or a stack of batteries?

Also I'd chk with someone to see if the tranny gears and others will be able to bear that amount of stress. 950hp seems a bit military tank to me?
__________________
______________________________
'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
Nine8Six is offline   Reply With Quote
Old 07-23-2014, 11:26 PM   #11
Registered User
 
Join Date: Feb 2011
Location: Sacramento
Posts: 98
The motor should make 400 lb/ft of torque with 2000 amps.
The supercaps can generate about 4000 amps for a few seconds,
How much can the single transaxle handle?

The motor weighs about 120 lbs. The caps and a 2 minute battery are about 200lbs.

I have a smaller 8in motor and lightweight transaxle thinking of putting it in the front mostly because I have it and its just been collecting dust. The motor is not an A/C motor so no regen/braking, which is kinda the point of the awd, but I have it and its pretty light.
Pic of it, the bottom right is the main A/C drive motor out of a Prius for size comparison.



nimblemotorsports is offline   Reply With Quote
Old 07-24-2014, 12:12 AM   #12
Registered User
 
Nine8Six's Avatar
 
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,216
Find out exactly what materials and dimensions you are dealing with and I'll run a few simulations for you. Luckily we are geared with a pretty fancy Simulation portfolio at the office that I'm sure I can use for personal use.

Mate, that thing you are building. Why I have a feeling it is going to shoot into a wall when you hit the "pedal" (called what, not a gas pedal?)
__________________
______________________________
'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
Nine8Six is offline   Reply With Quote
Old 07-24-2014, 12:28 AM   #13
Registered User
 
Nine8Six's Avatar
 
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,216
Just bringing back old school calculators... @ 400 lb/ft. That would equate about that 300+HP at let's say 4000rpm? Looking good if you ask me. How much for those batteries again?! I'll keep the engine in the back and add electric in the front (Hybrid 986 lol)

And where does this 950hp comes from? or have you decide to drop the rocket-fast idea already?
__________________
______________________________
'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
Nine8Six is offline   Reply With Quote
Old 07-24-2014, 07:57 AM   #14
Registered User
 
Brad Roberts's Avatar
 
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
You want C4 996 axles.. they go right in.

Why do you think the front anti roll bar has a "hump" in it at the end? It's to clear the axles...

also.. get the C4 front diff and mounting brackets..

also.. the C4 gas tank is different.. but you don't need that

the C4 axles are not very stout..

You will KILL KILL that puny ass 5 speed (your wasting your time) Get a 930 Turbo 4 speed. Stock they will handle 800lb ft. Leave it in 3rd gear.

I'm very close friends with the guy who developed the Zilla controllers. He rented shop space from me when we both lived in the SF bay area (Palo Alto)

I consulted him for years on his drag race 914. It was the test mule for his controllers. He blew up all kinds of sh_t... he runs two motors tied together with a top fuel blower belt..
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.

Last edited by Brad Roberts; 07-24-2014 at 07:59 AM.
Brad Roberts is offline   Reply With Quote
Old 07-24-2014, 08:43 AM   #15
Registered User
 
The Radium King's Avatar
 
Join Date: Apr 2010
Location: Canada
Posts: 2,987
I was thinking that would be a neat trick - keep the back end as-is and put a 996 c4 front end in. tie the front diff into an electric motor and put the batteries in the frunk. have a button to trigger it (ie, for straights on the track) probably interlocked with the clutch so that you don't overrev the engine. it would have to be regenerative, however, otherwise one shot wonder ...
The Radium King is offline   Reply With Quote
Old 07-24-2014, 09:13 AM   #16
Registered User
 
Brad Roberts's Avatar
 
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
You can use the rear shock, but you need the C4 upper shock mounts (this will raise the shock the proper amount) The Boxster uses 4 front shocks.. they just raise the rear and change the worthless metal tab hanging off the shock (the ABS wire holder)
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
Brad Roberts is offline   Reply With Quote
Old 07-24-2014, 09:15 AM   #17
Registered User
 
Brad Roberts's Avatar
 
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
Radium? this is exactly what Porsche did in the RSR hybrid. Two small electric motors and a flywheel storage system in the passenger floorboard Each front axle had its own small electric motor. New 918 uses the same system, minus the flywheel storage system
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
Brad Roberts is offline   Reply With Quote
Old 07-24-2014, 09:17 AM   #18
Registered User
 
Brad Roberts's Avatar
 
Join Date: Aug 2004
Location: Alta Loma, CA
Posts: 1,334
__________________
Engine Builds, Transmission Builds, Engine Conversions, Suspension Installs, Suspension Tuning, Driver Coaching, Data Acquisition, Video, SCCA/PCA/POC/NASA/GRAND AM/ALMS.
We have worked with amateur and professional drivers for over 26 years. In house machinist, In house fabrication. Our cars, our parts, our engines, our transmission's run nationwide at events every weekend. We work side by side with industry names developing parts.
Brad Roberts is offline   Reply With Quote
Old 07-25-2014, 09:19 AM   #19
Registered User
 
Join Date: Feb 2011
Location: Sacramento
Posts: 98
I was concerned about the transaxle strength.
I had the transaxle and a motor adapter already for it, so just put it in.
In fact, I picked up two C5 corvette differentials I was going to use,
no strength issue there, just more fab work and expense.

Red c5 z06 Nitrous Corvette drag racing at Edgewater 2012 - YouTube

A ragtop is not really ideal for this kind of car.
Might just go old school with a chopped top awd electric ghia and build it from scratch.


nimblemotorsports is offline   Reply With Quote
Old 07-25-2014, 09:42 AM   #20
Registered User
 
Nine8Six's Avatar
 
Join Date: Sep 2013
Location: Montreal, QC. (currently expat to Shanghai)
Posts: 3,216
Stupid question again (soory), is that car oversized or the building behind is just very small?

__________________
______________________________
'97 Boxster base model 2.5L, Guards Red/Tan leather, with a new but old Alpine am/fm radio.
Nine8Six is offline   Reply With Quote
Reply

Tags
all-wheel-drive , boxster , electric , supercaps


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On




All times are GMT -8. The time now is 11:02 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page