chris924S

It is possible to install an optima battery upright in 924S/944. Thanks to Alex Ho's pictures and advice, I was able to install a similar battery. I chose an Optima Red 34/78 battery for my 1988 924S.

I purchased the Red 34/78 from a local Pep Boys. (They have the Yellow with is identical in size. So you have a choice. ) I chose this size because it can be connected to the existing wiring without modification and can be mounted securely in an upright position with no need to buy anything extra, except for the purchase of a set of side terminal plugs ($2.99.) These plugs screw into the side terminal and come with soft vinyl cover caps, I think they are used to charge batteries that are only equipped with side terminals.

Step 1) Remove the old battery, check integrity of the negative and positive connections. The Optima Red 34/78 has side terminal connections, that is what you will use.

Step 2) Do not remove the covers from the top terminals. Instead remove the vinyl cover caps and screw the plugs into the side terminals. As an added precaution, install the vinyl cover caps over the plastic covered top terminals.

Step 3) Install the long black plastic adapter on the back side of the battery which will face the fender. It snaps in place. Then mount the battery and make sure the adapter fits under the mounting lip.

Step 4) Use the plastic triangular mount (GM) in place of the stock metal hold down. The plastic mount fits around the battery, while the stock one does not. The mount fits with just enough room to fit the 14mm mounting bolt. Tighten down until the battery feels secure.

Step 5) Attach the battery cables. You may need to play with the slack to get the fit just so. Install the stock battery cover, it will fit over the lip of the battery. You have a great battery and now have a stock appearance.

DFASTEST951

I called Optima and they told me if I remove the top terminals, they void the warranty. Make is simple, install it on its side, its an Optima!

Sam Lin

Chris' directions don't mention removing the top terminals...

???
Sam

chris924S

Thanks Sam. Its really simple, leave the top terminals alone! Keep them covered. I wanted another layer of insulation on top, that's why I used the vinyl terminal caps.

Don't even think about removing the top terminals, it can be dangerous and why monkey with voiding the warranty. If you are going to go that far. Just buy a regular 40R or 41 battery and change it after 3/4 years.

The Optima 34/78 battery is tall, but not that much taller than the stock battery, it's a little more than an inch higher. It will clear and not touch the hood, but as an added precaution, I also used the stock plastic battery cover.

Let me repeat, it is an upright install, so it is the same as stock. It is not necessary to mount sideways, because you are using the SIDE TERMINALS, not the top ones. This way it can be mounted as any other 40R or 41 battery. Just be sure to use the slender black mount (FORD-LINCOLN MERCERY) on the back part of the battery, and use the (GM) triangular mount instead of the stock hold-down.

It works, its simple, its safe, and the total install time took 20 minutes. (Less time than it took to write this reply,) I used the extra time to adjust the length of the cables in the battery box area, and to clean the terminals and battery connectors and coat them with a think layer of dielectric grease.

I would have never considered this method without reading Alex Ho's post, which I found by conducting a search for optima threads. When I sent him a message, he was gracious enough to share with me some additional thoughts, and pictures of his install.


That's why I wanted to share these additional thoughts with you guys.

I personally don't like the idea of mounting the 75/35 on it's side and then fashioning a new mounting plate, etc. As for mounting it upright, the slight difference in height (3/4-inch), does not make up for the fact that I would have to install a longer negative battery cable.

David Floyd

We need some pictures

Ag951

Or just buy one that fits. The optima 34R is designed to fit the 944 upright. The terminals are reversed (+ is on the inside rear corner) and the battery is short enough to not hit the hood (I keep the + covered anyway). I have one and it fits perfectly.

Apexx

I agree buy the proper optima when I bought mine it was an orange top since then I think it is just a red top with reversed terminals. It is tight clearance wise but it is mounted in the normal fashion. It has been installed for two years now and I have been to five track events and it has never made contact with the hood.

Ag951

I've never heard of the orange top. Just the red, yellow, and blue. The difference between the red and yellow is that the yellow is designed for applications where the alternator can't supply enough current to power the system (e.g. competition car stereos).

chris924S

I looked into the orange top (reverse terminals) too, but height-wise I thought it was a little too tall for me. I also wanted to buy a battery that was pretty common and in stock. The 78/34 Optimas are now carried by PepBoys and other stores. While the orange top is supposed to be available by special order, but good luck trying to get them to order it, because very few have heard of it.

The only sources for the battery are the online suppliers such as Batteriesareus and TNA Sports, and I did not want to order one and then have to deal with the hassle of return shipping ($25), if I didn't like the fit.

Did you have to use any additional insulation for the terminals? Or just the battery cover?

Thanks for added info.

Chris
1988 924S Grey 184,000 on daily driver, autocross and track car.

Apexx

They made orange tops for about one year. It was the first reversed terminal battery optima made. I was a red top inside so they just decided to put a red top on it and give it a different part number. This was less confusing because a different colored top usually denotes a different type of battery.

This is a link to an old page that has the orange top in it Orange Top

Water944t

Just my .02...

I work at a rather large Lexus dealership here in Arizona, where the life of a battery is measured in months, not years. We experimented for a while with replacement Optima batteries, as the Japanese batteries that came stock were dying out in approximately 18 months.

After 2 years the conclusion was that the average life of an Optima here in the AZ heat was approximately 18 months.

So, for twice the money we got pretty much the same performance, kinda like a few of the tuners/shops that handle our cars...

Now I certainly cannot speak for other climates or conditions, but it seems to me that a Checker/AutoZone special, with a 5 year warranty is a pretty good buy, since they are good about handing you a new one when the old one goes bonk.

And they fit properly too.

Sam Lin

Those're interesting results Water944t - I've known people who've run Optima Yellow Tops for 5-7 years here in AZ!

Sam

Ag951

As have I. Yellows and Reds. On race cars, street cars, and dual purpose cars.

tifosiman

How much lighter is an optima, compared to a standard battery for our cars?

And, has anyone given any thought to moving it to the right rear cubby in the hatch? It sounds like an optima would work perfect there with some custom fabbed brackets.

Ag951

It's quite a bit lighter that the regular style battery I replaced with it.
I think it would fit in the cubby, but I don't know if you'd want it back there.
My car has pretty good weight distribution, with me in the driver's seat, as it is. If I moved the battery the percentages would worsen.