ISO-heet and 2015 S3 apr stage 1

**dhomes** · 12-04-2022 09:42 AM

Has anyone here had experience with iso-heet on their tuned cars? Apr says not to use any gas additives but with my car at 76k miles I’d like to run a bottle of it through the fuel system and drive nice and slow while that tank runs

Any takes?

**MikTip** · 12-04-2022 10:09 AM

Additives...

They tend to dilute the lubricating abilities of the oil...which with these engine and the pre ignition issue and pistons might be bad...

APR tunes once had specific tune for 100+ octane fuels.

So my advise is if the tune does not support it....don't.

**dhomes** · 12-04-2022 10:15 AM

Mine had the 93 octane file, performance has been great but I’m notice a BIG drop in fuel efficiency since the tuned went in, wondering if it has to do with the injectors

**MikTip** · 12-04-2022 10:51 AM

Originally Posted by dhomes

Mine had the 93 octane file, performance has been great but I’m notice a BIG drop in fuel efficiency since the tuned went in, wondering if it has to do with the injectors

Carbon cleaned? Year? Miles?

Performance requires more fuel to make more power...

**dhomes** · 12-04-2022 11:09 AM

hey Mik, mine is 2015 / 76k miles. You mentioned you did your carbon cleaning yourself right? Just Liquid Molly on the engine?

Basically I'm getting 310 miles on a full tank

**texasboy21** · 12-04-2022 11:15 AM

Originally Posted by dhomes

Has anyone here had experience with iso-heet on their tuned cars? Apr says not to use any gas additives but with my car at 76k miles I’d like to run a bottle of it through the fuel system and drive nice and slow while that tank runs

Any takes?

What are you solving for the the iso-heet? Octane boost? Injector cleaning?

Ive run OE Audi fuel injector cleaner, as well as Liqui Moly Jectron without any troubles.

**texasboy21** · 12-04-2022 11:19 AM

Originally Posted by dhomes

Mine had the 93 octane file, performance has been great but I’m notice a BIG drop in fuel efficiency since the tuned went in, wondering if it has to do with the injectors

Well you're making a TON more power, there is a high likelyhood that you are using more throttle and therefore more gas..

Typically gas mileage improves once tuned because you use a lower percentage of total energy to get the car moving under normal driving conditions - compared to stock.

Get some data logs related to air, fuel, and timing to start painting a picture of how the car is running.

What is your hand calculated mileage pre tune? What is it now post tune?

**MikTip** · 12-04-2022 11:28 AM

Originally Posted by dhomes

hey Mik, mine is 2015 / 76k miles. You mentioned you did your carbon cleaning yourself right? Just Liquid Molly on the engine?

Basically I'm getting 310 miles on a full tank

Carbon cleaning involves removing the intake manifold and media blasting the valves...

Since the injectors are directly injecting gas into the combustion chambers...fuel additives wont clean the valves.

The valves get dirty from the oil fumes the engine ingests at the turbo inlet pipe.

A bad PVC/Oil separator will amplify the oil ingested and cause excessive carbon

Only way to clean is media blasting.

Maybe a 02 sensor going bad...other...hard to say without testing and an obd scanner.

**dhomes** · 12-04-2022 11:36 AM

my OBD throws 0 codes but it's a basic one: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

What do you recommend for a decently priced one? what do you normally get on a full gas of tank regular city drive? (since you and I have the same year s3)

**MikTip** · 12-04-2022 12:02 PM

Originally Posted by dhomes

my OBD throws 0 codes but it's a basic one: https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

What do you recommend for a decently priced one? what do you normally get on a full gas of tank regular city drive? (since you and I have the same year s3)

The problem with OBD scanners is they will not read all the various modules on the car. Generally you have to pay to play and buy an OBD for a fair amount before it will read all the modules.

I have and use Ross Techs VCDS. Have for many years. It works.

I don't monitor my MPG...

I fill up the tank and drive.

Its a 4 cylinder so its more gas conservative than a V8!