RSbob

NelaK

I've never used any additives or felt the need to... I don't think Porsche has a service interval on the fuel injectors and it sounds kind of strange that you'd be having an issue with them especially since the Cayenne takes premium gas which already has additives to prevent that.

Do you just have really bad gas where ever you are?

Petza914

In my 997 and Cayenne, I use Stabil 360 since those cars sometimes sit for weeks between drives and it could be a couple months before a full tank of gas is depleted. The Stabil keeps the fuel fresh so I don't have runnability issues with predetonation, etc.

In my 928 I use SeaFoam as it also stabilizes the fuel (same reason as above) but also lubricates the mechanical fuel distribution since it's a 79 and a K-Jet car

In the 914 I use Driven Card Defender

In all of them I run a full tank of gas with the correct amount of Techron fuel system cleaner in the last tank before an oil change as it's supposed to help remove carbon deposits and I want whatever it might remove that gets trapped in the oil or filter cleaned out asap, which is why the oil change right after that last tank.

Wisconsin Joe

None during normal use. Premium fuel has a comprehensive additive package.

My 928, 944 & motorcycle get parked during the winter, November through March (or April, or May this year ).
Those all get a dose of SeaFoam in a fresh tank of gas when parked.

I tend to be a bit skeptical of the promises in the ad copy for the additives. Increased power or fuel economy is a load of crap. For one tankful to clean injectors or jets is a bit of a stretch too. I would think you'd have to run it for a lot longer than that to get any significant results.

One exception to this is diesel anti-gel additives. Those not only work as advertised, but can be vital when it gets cold.

DWPC

My previous car was an Audi 2.7T that had some roughness issues. The Audi service mgr told me to run a bottle of Techron through it before bringing it in. I did and it cleared it up nicely and mileage improved. I've used Techron every 5K miles or so ever since.

Vivid7

none. Shell V power 93 only

Joefus

Petza914 - How does the Techron show in the Oil Analysis if it goes in just before you drop the oil or do you take a sample of oil before that thru the dipstick? Thanks

Petza914

Techron is a fuel tank additive, not an oil one - I don't believe in those as the base stocks of the additive can be incompatible with either the base stock or additive package in the motor oil and create issues.

I've noted the addition of Techron in the comments section in a couple of my samples submissions and they always say something like "thanks for letting us know, but that additive burns away cleanly and doesn't skew anything or appear in oil results" so I stopped noting it even though I still use it.

Joefus

Thanks - I saw the line "it's supposed to help remove carbon deposits and I want whatever it might remove that gets trapped in the oil or filter cleaned out asap" which is what made me ask the question.

Petza914

UOA can't really detect things like that - carbon, plastics, etc so it's not perfect. For example, you could have a loose timing chain tensioner in a 997 that's causing wear on the plastic tensioner paddle guide and not see that in the UOA until the chain wears all the way through the plastic guide and into the aluminum tensioner paddle itself, but you'd hear that happening before it progressed that far.

That's why in addition to UOA you should cut your metal cm filter canisters open to check for any debris too. That's pretty easy to do with one of these filter cutters.

Pillow

Regular Unleaded. (I bet I'm not the only one... Especially the V6 guys Regular all day long)

I don't mind giving away the 10HP in reduced timing. In no way shape or form is this S pushed that hard in DD life.

RSbob

Petza914

In a base or an S, that might be OK, but not in a turbo or GTS The GTS is tuned differently where you'd like get knock from predestination, which is especially bad on a DFI motor - research LSPI - and on a turbo the boost pressure makes that even more likely is the octane rating isn't high enough to prevent it.

RazMan

Hey don't forget the oil burners? I often bung some 2 stroke oil in the tank when filling up - it really helps reduce some of the diesel 'clatter' and makes things noticeably smoother

Pillow

I agree with the Turbo models needing Premium.

LSPI, IDK if that would be applicable to the CTT... 4.8L Larger displacement and not so much emphasis on peak torque all in at low RPM. The newest econo grenades are asking for peak torque at 1000RPM high boost and minimal displacement because Automatics and replacement for displacement. If the MAP sensor is off or timing isn't calibrated to cut immediately when boost hits then that is a problem... Screw it - more E85 and get all the octane and timing! LOL