A while back, while cruising all the PHEV conversion posts/threads I came across a post that mentioned another source for the heavier springs that are needed with the 10Kwh conversion. It mentioned a source with a name like "spring city" and was in Calif. I think. Well "spring city" doesn't search well and I haven't been able to locate that source. The price was $270/set including shipping. Can't find the post or this spring dealer. Anyone remember this or aware of this source?? Steve
I know you can order specific spring rates pairs (2) from Ground Control for about $120. Ground Control Systems, Inc. 3885 Dividend Dr. Shingle Springs, CA 95667 P - 530-677-8600 I worked with Adam there to get my custom spring rates. If you have a touring model (not sure it makes a difference for the non-touring) Your looking for an 8" spring with a 2.5 I.D. with whatever spring rate you want. When I was ordering my springs, I got a GC200.64.58: 8 inches long, 2 1/2 I.D., 340lbs/inch until I realized I wanted to go lower then I ordered GC180.64.61, 7 inches long, 2 1/2 I.D., 350 lbs/inch. Not sure of the conversion of newtons are but Ken said this,
so.... apparently there are nifty conversions calculators here: Convert newton meter to pound-force inch [lbf·in] • Mechanics • Torque • Compact Calculator ....and this gives us..G2 Prius 2004-2009 Touring Front=212 lbs/in, Rear=252 lbs/in Normal Front=212 lbs/in, Rear=265 lbs/in I went with GC/Eibachs that were Rear=350 lb/in and even with 2 full size adults and luggage...it sags a bit. Guessing that batteries are somewhere between 150-200lbs which is less weight than my two full size adults in luggage... I would guess you need at least 350lb especially if you plan on loading up the car ever fully with luggage, adults plus the weight of the extra battery.
This isn't a good conversion. A newton is a force unit (like a lbf). A Newton-meter is a measurement of torque (like a lbf-in, *not* a lbf/in spring rate). The missing unit is what length unit is used in Ken's quoted spring rates (N/mm I'm guessing). Once you know that you can do the conversion properly. Try this: Spring Rate Converter Using this converter 24 N/mm = 137 lb(f)/in, 28.5 N/mm = 163 lb/in and 30 N/mm = 171 lb/in.
I contacted Ground Control the other day and the fellow I talked with said he didn't know what I would need since they had no expereince with the Prius. He could only offer springs that were 2 .5" ID. Hmm! He would need more information from me. So from your experience and other discussions here, what would you guys recommend for my gen2 standard with normal passenger load plus 10kwh battery pack, etc. say 350 with other gear in back. Seems like the GC180.64.61, 7"X2.5.?? Price seems right since PIS wants $300 for a pair. steve
Not the GC180.64.61, Its a 7" spring. Look Into the GC200.64.58 because Its at least an 8" spring. Try talking to the sales guy and ask what lengths they come In. Keep in mind my springs sit on a spring seat perch. I ordered the 7" because 8" wouldn't allow me to lower my as much as I wanted. I wouldn't go with a shorter than 8" spring unless ur trying to lower the car. You may actually want taller than 8"...maybe 9 or 10". If you look in the photo, you'll see the 8" spring doesn't cover the entire length that the oem spring would.
Those spring rates seem a bit off even though you used a different conversion calculator. 137lbs springs seem extremely soft...
Now I think I understand what you did and are talking about. Now I think I need to take a stock Prius spring and found out what the length is. Then maybe do the math or guestimate from there. The formulas seem to be Pounds per inch of compression so I know I want to be able to carry an additional 300 lbs of the battery pack. (wonder if that is per pair or per spring??) I have a parts car here so I will pull a shock and measure the unloaded length. I guess a guy could just measure that with the wheel off the ground and on load on the shock. Might be close enough to give the experts to calculate from. Sorry, just thinking out loud! Steve
If I get time this week I'll check my storage to see if I still have my old springs and I'll take some measurements and report back.
Nah! Never found anything other than Plug in Supply. So I ordered mine from them. Sorry, I for got to take any measurements. I suppose I could jack mine up and count the coils and diameter of the spring stock. Not really sure what the spring people need to come up with a spec or part number. I'll say this, they sure improve the handling and the look after you install them with the extra 200# of batteries behind the rear suspension. Steve
Hey Steve, I often drive lots of freeway miles with a significant load and so I have a similar concern as you... But I'm thinking the solution isn't stronger or higher springs in the rear, but simply a pair of lowering springs up front. It makes sense that Ground Control would have more experience with selling lowering springs than heavy hauling springs. I sent Ground-control a message and plan to follow up next week. I'll report back if I learn anything new.
