Eggplant Cab

Yup I have for the last 9 years. 2 - 3 bottles a year on the older car. 1 on the new cars. I like it over the Chevron Techron. Works great on my 94 C2 Cab.

Shifty

How about octane boosters/ injector cleaner combos??
Miguel

Marc Shaw

Seems like a lot of snake-oil to me... see here.
Marc

Bearclaw

This article was written in 1992, and things have changed somewhat since then.
I agree with a lot of his assertions; in particular, Slick50's credibility and resulting legal problems are well-known. However, I have a problem with this statement:

"As a basic rule of thumb, using the standard engine oil recommended by your bike's manufacturer and changing it about every 3000 miles will afford you all the protection you'll ever need."

IMO, good-quality dino oil is perfectly fine for everyday use. But in the event of an overheating episode, a full synthetic will afford much more protection against piston scuffing and other damage. How much that protection is worth to you is a personal decision, especially when you're talking about 11 qts. of oil. And certainly, the debate of dino vs. synth. is an entirely different thread that could go on forever. But I personally think that it's worth it.

The gas additives talked about in this thread so far are pretty legitimate products, I think. Just personal choice about whether you think they're worth it.

cypresscoast

Hey!

Some one mentioned that they add 100% octane to their tank every so often. I live in central California, it's sold at a local 76. Can I use it and what ratio do you recommend for my 1990 C2 with 88K?

What about the computer, will it be harmed by having to adjust?

Thanks!

It's raining here today and perhaps tomorrow too..

Eggplant Cab

I dump in 100 octane with 91 to get 94 or 95 aki for my 997 once in awhile in the last 2 mths. Gives me back about 3-7hp, which you cannot feel but feels good knowing the car is at its best.
I do it for the 964 once in a while too. Just for fun.
As for octane boosters, not too many of them work that well. NOS has MMT which works well but apparently too much MMT is killer for your cat.
100 octane fuel is basically a mix of toluene and some spirits. The 76 sold race fuel 100 octane is emissions legal. All the other octane boosters may not be.
I use a 3:1 ratio when I do fill to get 93 octane. That's 3 gallons of 91 and 1 gallon of 100.
In the 18 gallon 964, that's 13.5(@ $3.6) gallons of 91 and 4.5(@$6.12)gallons of 100 octane. That's $76 bucks a tank vs $64 for 91 which is really nothing. I'd do it everyday if the gas station wasn't so far away and the 100 octane pump closes from 11pm-5am (So to stop the street racers from refueling!).
Of course I knew a few nutters who mix their own brew of toluene (it's a paint thinner and readily available at chem and paint stores in barrels even!). Problem with toluene is that it requires really high temps to burn, so any excess will just fry your cat. Plus while there's some indication it's not as toxic as believed once, it's still pretty dangerous to expose yourself to it.
My M5 loves 94 aki mixes and in that car you can feel the difference. Pickup is smoother and slight stronger.
If you have modified your engine (esp a turbo with over boost) higher octane is good. However with the stock 964, I dynoed 245 FWhp on 91 octane. So I think it's as good as it gets really.
You can also try Rockett Fuel Brand. These are the guys who left unocal when they quit Nascar sponsorship.
The 997 forum also has more on octane boosters:
https://rennlist.com/forums/997-forum/226424-93-octane-do-cali-members-use-boost-products.html

springer3

Ditto here. Common sense: if you use quality gas and oil, it is an optimal blend of known ingredients carefully developed and tested. If you buy bad gas or bad oil, how can you expect some unknown chemical(s) to make it better? Porsche recommends against any additives. They know that some do harm, and most are simply a waste of money.