1988 Carrera battery replacement

[MarkY]

After owning my 88 Carrera for 13 years, my the battery finally took a dump. It is an Interstate MTP-93. Current retail price for this bad boy is $225. Any cheaper alternatives that would be an easy swap. Not interested in an Optima.

Also, at first glance it isn't readily apparent how this thing is held in place. Any tips or pointers to a tech guide greatly appreciated.

Mark

[aigel]

I just put an odyssey 925 in my 993. But that's about as much with the adapter. The nice thing with the dry batteries is that you do not have to vent them to the outside.

I have always had good luck with WalMart batteries. EverStart, or as we call them NeverStart jokingly. You can spring for the top model that has 3 year free replacement plus 7 year total prorated replacement. Keep the receipt in the car and you can get a new battery anywhere in the country.

Your battery removes with a single bolt holding down the battery at the botom. Check the perimeter of the battery. Also, when you take out the battery, remove the negative terminal first.

Hope this helps.

G

[nineball]

my alternative

http://forums.pelicanparts.com/porsche-911-technical-forum/551173-another-battery-install-thread.html

[porschenut]

If you got 13 years out of the last MTP-93, I don't know why you'd be put off by $225 for another one. The Interstate is as good as any battery you can put in there. Odyssey batteries seem to be good alternatives if weight is an issue, but they won't be much cheaper and require special brackets or adapters to install them.

Not sure why you don't like Optimas. The Red Top is a great battery which I've used for many years. But I wouldn't say it's any better than an Interstate.

[nineball]

fwiw the modern optimas seem to be nothing compared to years ago. i personally had one fail on me after 7 months and have a few friends who have had similar results. there are many good alternatives for their cost as you are paying a premium for the name.

[Ned, NYNA11]

Get a smaller one. Less PIA getting it in and the re is another threaded hole down there to fasten the hold down clamp.

[darrin]

this thread has some good options -- http://forums.pelicanparts.com/porsche-911-technical-forum/467802-replacement-battery.html

getting close to heading the group 48 agm battery route myself as it will fit in the stock location without mods, is smaller and lighter and uses the Advanced Glass Mat technology so (like an optima,etc.) it won't leak acid.

d

[boxster03]

13 years from a battery ? wow that is worth writing to the company about

[MarkY]

Get this. I have all the records from my 1988 Carrera and I found the receipt for the Interstate. It was purchased June 28, 1999.





Actually, the reason I was asking about others is the size of this thing. Although it has a handle, it looks like a real PITA to replace.

I'm actually quite surprised this battery has lasted this long in Phoenix. But I don't have a ton of starts on this car. Battery replaced with 15k miles, and my car only has 36k miles now.

[aigel]

That thread indeed has a lot of good info.

I find the stock battery too large and heavy. It was sized for all climates, including Germany. If you don't have any freezing weather starts with the car sitting outside, I believe you can get away with a lot less ...

G

[Tincanguy]

Just bought an Interstate MTP91 for my 1988 Targa from the local Firestone tire store for $129.95. R&Rd it myself. Identical to the old one that lasted 7 years. Heavy, and a tight fit but doable with standard tools. Comes with an attached lifting strap which helps to horse it into place.

[MarkY]

Originally Posted by Tincanguy

Just bought an Interstate MTP91 for my 1988 Targa from the local Firestone tire store for $129.95. R&Rd it myself. Identical to the old one that lasted 7 years. Heavy, and a tight fit but doable with standard tools. Comes with an attached lifting strap which helps to horse it into place.

Any tricks you want to share? How long did the job take?

Thanks

[Halm]

FWIW, I just went to the Interstate fitment guide. For a SC, it says MTP-49, with a suggested list of $185. Assuming that is the correct fit, I am going to the local Interstate store and doing that.

I have saved this Pelican article for years, but as said in this thread, I am hearing too often that Optima quality is not up to their reputation any longer.

[msterling]

My '88 had a monster Interstate battery (MTP-93 like yours) that was still good after 10yrs but the PO had installed it without connecting the vent tube. When I started to Autocross the battery started to leak from the vent and caused some minor damage before I discovered the problem. I installed a somewhat smaller Diehard AGM which actually has more capacity. I had to make a very simple custom mount out of a plastic cutting board which is held down with the original clamp. I was also able to use the original battery cables. Here is the one I bought.

Detail of clamp at front. This is the clamp to remove when you pull your battery.

[Halm]

msterling. Very similar to the link I posted. It looks like your setup uses nylon tie-downs that are between the plate and the car. Is that correct?

[msterling]

Originally Posted by Halm

msterling. Very similar to the link I posted. It looks like your setup uses nylon tie-downs that are between the plate and the car. Is that correct?

Yes that's right. Really heavy duty tie downs. After that pic was taken I also installed a stop block at the front to keep the battery from moving forward. I don't think it will do anything unless there is a frontal impact. Belt + suspenders method.

I didn't have room on either side of the battery to run fasteners up through the base. The Optima batteries have a base that allows this.

[TheRedSlantnose]

A fellow Porsche owner once told me you can use a motorcycle or gel battery to save weight.

[crownarch]

I just ordered a new Napa Legend Battery (BAT 9849) which will be in the store this coming Monday. Cost on it was $204 but, is well worth it as this battery has a 75 month warranty and an AGM but, last one went beyond 13 years. The battery weighs in at 58 lbs. but, fits perfect and is a little tricky to install. I use a large piece of thick clear plastic sheeting laid over and down the side of the fuel tank. Keeps the fuel tank from being marred up and battery laid along it will slide in place real easy.

[aigel]

I am not a fan of plastic or wood tie down adapters. They will hold up fine in normal driving, but if things start moving around in a collision with the fuel tank close by, it can be very bad news. I would only use a metal adapter and also recommend covering the positive terminal with insulation.

HTH,

G

[Michael T]

I had an Optima in my former 1987 Targa that begin smoking. Alternator, voltage regulator all were fine. I would not buy one. I have had great luck with Interstate.