last few times starting the car (and here in the northeast its been getting very unfrequent due to the weather) i feel like the battery is getting weaker and weaker.

i just finished searching. much information about batteries , but no optima red top model numbers.

I am assuming that most people here with optima red top batteries go for the 34r.

-reversed polarity is what we need. right?

http://www.optimabatteries.com/publi...cal_specs.html

out of the above site/charts it looks like that is in fact the most powerful red/top available.


initially i was planning on saving weight, so tried using the an aftermarket battery from my e46m3. The optima yellow top d51r.

http://www.optimabatteries.com/publi...cal_specs.html

Only problem with the yellow top (as you can see from the charts on the yellowtop section), is that the height is 8 15/16 inches. When i tried installing this a few weeks ago, the posts were about half an inch too tall, and the battery cover under the hood barely clipped in. It looked really funny.

In addition to not fitting, i figured i might as well get somethin more powerful, since the yellowtop has only 500cca. (however it is pretty lightweight, weighin in at only 26lbs --worked really well in my m3 with no charging or hassels)

What i want to know is the following:

optima red top 34r. is this the right way to go? i noticed a few people on the forums talk about having optima red tops, but no where do i see any reference to model numbers.
-also, any good places to prchase the battery?

Thanks

 

I just purchased a Red Top 35 and fabricated an altered mounting assembly. It has 720 CCA at 0 and saved me about 20 lbs over stock Porsche. Weighs in at 31.7 whereas the 34R is advertised at 37.9. I felt it the best compromise between weight and performance.

The cables fit nicely and it goes into the stock pan but you must fabricate a piece to go under the standard hold down clamp. You have to catch the Optima at its front and rear corners. I also cut a piece of 1/4 " Lexan that wedges in front of the battery to keep it from moving forward. It slips under the new bracket on the passenger side and safety wires on the driver side through a little 1/16'' hole I made in the pan. That was the only modification that was required to the stock piece. I'm sure there are other ways to do it but that was the way I chose.

 

Check out this post: https://www.6speedonline.com/forums/...ad.php?t=73725

I got the Optima Red Top model # RT S 4.2 which is a group 34 battery. The one I received didn't have a rectangle bottom that I could mount it to the tray with bolts. Besides, I didn't feel the battery would be secure enough with bolts to a plastic battery trim holding it down.

Good luck.

 

thanks guys..


al, i just orderd the red top 35 as well... seems more powerful than stock and like you said, lighter than the 34 model.

ill update with how it went.
thanks.

 

I think it is the best choice for reliability and weight loss. If you need a suggestion as to how to mount it, I can post pictures of what I did.

Al

 

al:

if you dont mind a picture of the install would be great.
thanks

 

Took Pics and have misplaced the cable that connects the camera to the computer. When I find it, I will try to upload. Have most often not been successful with picture uploads.

 

I took the pictures, and have tried every way I know but can't get them to upload.

Sorry.

 

Finally remembered how to post pictures. The battery is not yet installed in the car, but you can imagine how it will look from the pictures I have posted.

At installation time, I will loosen the original hold-down clamp, snip the safety wire and remove the items that I will describe below in more detail. I will then be able to to free the battery for removal from the original battery tray.

I will replace the original tray and install the 4 bolts that secure it and then install the battery in the order that you might imagine. The cables will reattach with no strain.

This is the overall view of the battery assemble on my workbench with the fabricated bracket being held in place by the original clamping piece.





Here is a close-up view of the fabricated bracket. It follows the curvature of the battery both fore and aft and has a brake-bent offset to better parallel the top of the battery base. There is a slitted section of fuel line buffering the 3/32" piece of steel from the plastic battery case. The detail may be a bit difficult to see, since everything but the Lexan is black. The strip of 1/4" Lexan wedged in front of the battery is a shim causing the back of the battery to be secured beneath the undercut lip at the rear of the tray. Notice that the passenger-side edge of the Lexan is trapped securely beneath the new bracket.





The Lexan extends the full width of the battery and is secured on the driver's side with a piece of 0.041" safety wire. The 1/16" hole is the only modification I had to make to the original tray. It will not be readily visible if one decides to go back to the stock configuration.





A somewhat complicated pair of pieces to make, but I feel it provides a secure mounting for the Optima 35 and adds only 6 oz. for those of you weight-conscious folk---like me.

Well, I thought the pictures would enlarge when clicked upon, but they won't for me. Wish I knew what I did wrong.

 

al, thanks alot!

i will update when i recieve the battery. thanks again.

 

No one makes a optima bracket?

 

Yes, several are available, but for which style battery, I don't know. most of them are in the high 200's for cost and I wasn't willing to pay that amount, even if it would firt my 35.

 

Costco sells them and the price is great.

 

Moe is correct, ~ $120 at Costco

Bill

 

Bill,

Does it fit a specific series, or is it adjustable? Does it require drilling in the pan for a bolt-through?

I just included this picture to see if I actually had learned to resize one, and obviously I did.