Engine Decarbon Service

[noisuf]

Ok...I picked up some parts for my Subie this morning...so I drove the R32 to get their opinion on where to apply the UEC...

So here are some pics with yellow arrow pointing to the same line they suggest...What do you think? Originally, they suggested taking off the main intake pipe...the big arrow with the ???.

[break]

Don't do it through the main intake pipe, as it will mean you will need to spray past/through the throttle body which is really bad.

The line marked in the second pic looks suitable to me.

[noisuf]

Thanks Break...I had the thought that I wasn't comfortable doing it through the main pipe when they first suggested it...

[manol]

Ok...I picked up some parts for my Subie this morning...so I drove the R32 to get their opinion on where to apply the UEC...

So here are some pics with yellow arrow pointing to the same line they suggest...What do you think? Originally, they suggested taking off the main intake pipe...the big arrow with the ???.

You do realise that your R32 engine doesn't suffer from these issues because it's not a direct injection motor, right?

[noisuf]

You do realise that your R32 engine doesn't suffer from these issues because it's not a direct injection motor, right?

Hey Manol, I haven't applied it yet so good to see your post. Can you please explain more about the R32 engines in terms of fuel supply and why it wouldn't benefit?


Ok, since writing my reply above, I've spent the past 1/2 hour doing a bit more reading. There's conflicting info out there on the net about this engine whether it's direct injection or multipoint fuel injection. It looks like it's a multipoint fuel injection.

If this is the case, I'm wondering why an upper engine cleaner won't be beneficial? Isn't the carbon buildup from the fuel being injected onto the back of the valve?

[break]

ANY engine can benefit for decarbonation if it has carbon build ups (which anything over 100k will likely have at least small deposits here or there)

Cleaning the valves on a direct injection motor which are covered in oily build up, and cleaning out the carbon from the upper engine are two separate things. Yes you can use the same product to clean both, but cleaning oil build up on valves isn't the sole reasont to run these products through the motor.

A good example is a friend who was having horrible detonation on his S15 200sx when trying to get his new NisTune ECU tuned, leading to a poor result of 153rwkw at 13psi. Tried a whole heap of fixes (new fuel filter, cleaned the injectors, swapped the BOV), only to eventually be diagnosed by a workshop with carbon build up. The workshop pulled the plugs and directly sprayed Subaru Upper Engine Cleaner into each cylinder, as well as doing the traditional plenum spray to coat the intake valves, following by putting it back together and spraying the rest of the can through the motor as it ran.

Post the clean, they managed to get it up to 186rwkw at 18psi, on the same dyno with the same tank of fuel.

That's an extreme example, but you can see a handful of hp (I'd guess up to 5hp or so) restored by a clean on a >100k motor.

[noisuf]

my r32 has just clocked over 40000kms.

1) is the engine direct injection or multipoint? Doesn't seem it matters when it comes to using uec or not?

2) does a 40000km engine need to use it? If so, how often? I remeber subaru used it on my turbo forester every service...well, they charged me for it anyway.

3) inserting uec in plenum is sufficient...don't need to go to the extent of removing plugs?

[break]

my r32 has just clocked over 40000kms.

1) is the engine direct injection or multipoint? Doesn't seem it matters when it comes to using uec or not?

2) does a 40000km engine need to use it? If so, how often? I remeber subaru used it on my turbo forester every service...well, they charged me for it anyway.

3) inserting uec in plenum is sufficient...don't need to go to the extent of removing plugs?

1. I have no idea

2. Any engine can benefit from regular upper engine cleaning (around every 15-20k is good). That said, make sure you do it just prior to an oil change, as factory oil breathers can cause the oil to become slightly contaminated.

3. If you do the treatment regularly then into the plenum is fine... putting it in through the plugs is only really required if you need an extra thorough job of cleaning carbon, particularly hot spots on the pistons that turbo motors can often suffer from after 100k+

[noisuf]

thanks mate. will be doing it for the first time on my forrie tomorrow morning...test run for the r32...

[break]

thanks mate. will be doing it for the first time on my forrie tomorrow morning...test run for the r32...

Cool, let us know how you go.

Make sure you have a friend handy to help you as well... as you'll need someone in the car giving it a little gas to prevent it from stalling while running the mixture through.

Edit: Also, don't get it in your eyes. I learnt the hard way what petrol + methanol do to your eyes when you accidentally knock the straw off the can mid-spray. Holy **** that hurt while I ran over to the hose to rinse it out for the next 20mins

[noisuf]

Cool, let us know how you go.

Make sure you have a friend handy to help you as well... as you'll need someone in the car giving it a little gas to prevent it from stalling while running the mixture through.

Edit: Also, don't get it in your eyes. I learnt the hard way what petrol + methanol do to your eyes when you accidentally knock the straw off the can mid-spray. Holy **** that hurt while I ran over to the hose to rinse it out for the next 20mins

I did it this morning when I rocked up at my mechanics.

I brought along my vacuum cleaner's adjustable handle so that I could put it between the pedal and the seat (the forrie is drive by wire so can't control from front).

All went pretty well, no smoke actually came out...probably because I always use 98 ron, use subaru fuel additve every 6,000kms.

Learnt the following though:

1) It takes a while for the spray to get 'sucked' for the first half of the can. I think I didn't get half in before letting it sick for 5 mins.

2) Maybe shorter vacuum hose to help with 1)...

3) Might sound anal but maybe use scales next time to ensure half can used.