DFI Fuel System Cleaning - Carbon Buildup
10-01-2017, 12:02 AM
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DFI Fuel System Cleaning - Carbon Buildup
Topic: carbon build-up in DFI engines, specifically on intake valves no longer being sprayed directly with fuel, and the potential for decreased performance.
I realize there’s not a ton of talk on this topic nor does this seem to be a major issue with Porsche DFI engines (mine is a 2010 911 C2S) - especially as compared to some nightmares you hear about certain audi and bmw engines. It seems Porsche has minimized the problem pretty good. Maybe.
I discussed with my local Porsche dealer and they are now recommending a fuel system treatment every 30k miles. They used a BG complete fuel system treatment (BG GDI Service Kit) which consists of several components. Interesting YouTube video on the exact BG kit my dealer used:
They charged $380 for the service. I realize this may be steep for those who are DIY or who can have an independent try to do this for less. The service is more than just the fuel additive of course, they use a “machine” that apparently does the job more thoroughly.
After the service my car appeared to have a bit more kick to it. It very well may be in my head, but there has to be some truth to carbon build up in these engines. Even if Porsche has built a more carbon resistant design, I imagine it’s not immune to the effects of DFI carbon build up.
I found the youtube video interesting and the fact that the dealers are formally recommending this treatment.
Anybody else have have any experience good or bad on the topic? Just thought I’d share my thoughts on the topic and recent interaction with my dealer about the service.
I realize there’s not a ton of talk on this topic nor does this seem to be a major issue with Porsche DFI engines (mine is a 2010 911 C2S) - especially as compared to some nightmares you hear about certain audi and bmw engines. It seems Porsche has minimized the problem pretty good. Maybe.
I discussed with my local Porsche dealer and they are now recommending a fuel system treatment every 30k miles. They used a BG complete fuel system treatment (BG GDI Service Kit) which consists of several components. Interesting YouTube video on the exact BG kit my dealer used:
They charged $380 for the service. I realize this may be steep for those who are DIY or who can have an independent try to do this for less. The service is more than just the fuel additive of course, they use a “machine” that apparently does the job more thoroughly.
After the service my car appeared to have a bit more kick to it. It very well may be in my head, but there has to be some truth to carbon build up in these engines. Even if Porsche has built a more carbon resistant design, I imagine it’s not immune to the effects of DFI carbon build up.
I found the youtube video interesting and the fact that the dealers are formally recommending this treatment.
Anybody else have have any experience good or bad on the topic? Just thought I’d share my thoughts on the topic and recent interaction with my dealer about the service.
10-05-2017, 01:30 PM
#2
Instructor
Interesting timing on your post.
I have noticed that my engine's performance has recently dropped in the upper RPM range. I also noticed my exhaust pipe has changed from a slightly grey color to a very white color, which indicates the engine is now running excessively lean.
I did a bit of research and concur that cleaning (at a minimum) needs to be done around 30,000 miles (my engine has 41,000). I can buy new Bosch injectors for $190, or I can spend $300 to have old injectors cleaned. No brainer, I ordered new injectors. Will take a couple hours to install them.
Many people think incorrectly that injectors last a lifetime, they do not. They are a wear item. Manufacturers project 50,000 to 100,000 miles depending on application. Honda Civic commuter car? 100,000 miles. Performance car revved to 6000 or 7000 rpm? 40,000 to 50,000. More track days means the injectors' life is shorter. The difference can be felt across the entire RPM band. People that only daily drive their cars will always claim that their injectors are as good as new and their car has the same performance as new. That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually. The only way to see if your 5 year old injectors are working like new is to remove them and test them in an injector tester to visually see the pattern. By the time you spend that money, you could have just bought new injectors. So replacement as a normal part of maintenance is more economical and keeps the car performing as new.
I have noticed that my engine's performance has recently dropped in the upper RPM range. I also noticed my exhaust pipe has changed from a slightly grey color to a very white color, which indicates the engine is now running excessively lean.
I did a bit of research and concur that cleaning (at a minimum) needs to be done around 30,000 miles (my engine has 41,000). I can buy new Bosch injectors for $190, or I can spend $300 to have old injectors cleaned. No brainer, I ordered new injectors. Will take a couple hours to install them.
Many people think incorrectly that injectors last a lifetime, they do not. They are a wear item. Manufacturers project 50,000 to 100,000 miles depending on application. Honda Civic commuter car? 100,000 miles. Performance car revved to 6000 or 7000 rpm? 40,000 to 50,000. More track days means the injectors' life is shorter. The difference can be felt across the entire RPM band. People that only daily drive their cars will always claim that their injectors are as good as new and their car has the same performance as new. That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually. The only way to see if your 5 year old injectors are working like new is to remove them and test them in an injector tester to visually see the pattern. By the time you spend that money, you could have just bought new injectors. So replacement as a normal part of maintenance is more economical and keeps the car performing as new.
10-05-2017, 02:27 PM
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Interesting timing on your post.
I have noticed that my engine's performance has recently dropped in the upper RPM range. I also noticed my exhaust pipe has changed from a slightly grey color to a very white color, which indicates the engine is now running excessively lean.
I did a bit of research and concur that cleaning (at a minimum) needs to be done around 30,000 miles (my engine has 41,000). I can buy new Bosch injectors for $190, or I can spend $300 to have old injectors cleaned. No brainer, I ordered new injectors. Will take a couple hours to install them.
Many people think incorrectly that injectors last a lifetime, they do not. They are a wear item. Manufacturers project 50,000 to 100,000 miles depending on application. Honda Civic commuter car? 100,000 miles. Performance car revved to 6000 or 7000 rpm? 40,000 to 50,000. More track days means the injectors' life is shorter. The difference can be felt across the entire RPM band. People that only daily drive their cars will always claim that their injectors are as good as new and their car has the same performance as new. That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually. The only way to see if your 5 year old injectors are working like new is to remove them and test them in an injector tester to visually see the pattern. By the time you spend that money, you could have just bought new injectors. So replacement as a normal part of maintenance is more economical and keeps the car performing as new.
I have noticed that my engine's performance has recently dropped in the upper RPM range. I also noticed my exhaust pipe has changed from a slightly grey color to a very white color, which indicates the engine is now running excessively lean.
I did a bit of research and concur that cleaning (at a minimum) needs to be done around 30,000 miles (my engine has 41,000). I can buy new Bosch injectors for $190, or I can spend $300 to have old injectors cleaned. No brainer, I ordered new injectors. Will take a couple hours to install them.
Many people think incorrectly that injectors last a lifetime, they do not. They are a wear item. Manufacturers project 50,000 to 100,000 miles depending on application. Honda Civic commuter car? 100,000 miles. Performance car revved to 6000 or 7000 rpm? 40,000 to 50,000. More track days means the injectors' life is shorter. The difference can be felt across the entire RPM band. People that only daily drive their cars will always claim that their injectors are as good as new and their car has the same performance as new. That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually. The only way to see if your 5 year old injectors are working like new is to remove them and test them in an injector tester to visually see the pattern. By the time you spend that money, you could have just bought new injectors. So replacement as a normal part of maintenance is more economical and keeps the car performing as new.
10-11-2017, 10:55 PM
#4
I think this is a good preventative measure *if* performed on a very frequent basis, but it probably has to be too frequent to consider feasible. Crankcase blowby, baked onto intake valves and ports into carbon deposits are very stubborn to remove. It's definitely not something that will be removed by spraying a solvent for a couple minutes in the interval of tens of thousands of miles. Hundreds or even thousands of heat cycles between oil changes means one treatment every oil change is too infrequent. In my eyes, the only thing feasible is what BMW does, Walnut Blasting every ~30k miles, and even more frequently if your car isn't driven often or only for short distances in the city.
10-13-2017, 10:21 AM
#5
RL Community Team
Rennlist Member
Rennlist Member
2009 C2S 118K miles
I am very skeptical about this treatment. I am not against it, I just have not heard any solid evidence it is required or even helps.
My source of information is the 'net on this one, but you can pull some good information if you sift appropriately, and I really can't recall anyone with these DFI engines having any issues. I have 118K miles and honestly don't believe I have buildup..... maybe I do but am ignorant to it.
I do run Techron a few times a year in the fuel.... one time a put a bottle into a 1/2 tank and then did that again the next 1/2 fill..... I could never tell a difference. I know, the fuel spray doesn't hit the back of the valves, although there are some Porsche produced diagrams that hint the spray does hit the back a bit.... controversial.
Anywho, again, I have seen no evidence that this is needed. The real evidence is a photo of a crudded up valve.... Porsche that is.
Peace
Bruce in Philly
I am very skeptical about this treatment. I am not against it, I just have not heard any solid evidence it is required or even helps.
My source of information is the 'net on this one, but you can pull some good information if you sift appropriately, and I really can't recall anyone with these DFI engines having any issues. I have 118K miles and honestly don't believe I have buildup..... maybe I do but am ignorant to it.
I do run Techron a few times a year in the fuel.... one time a put a bottle into a 1/2 tank and then did that again the next 1/2 fill..... I could never tell a difference. I know, the fuel spray doesn't hit the back of the valves, although there are some Porsche produced diagrams that hint the spray does hit the back a bit.... controversial.
Anywho, again, I have seen no evidence that this is needed. The real evidence is a photo of a crudded up valve.... Porsche that is.
Peace
Bruce in Philly
10-13-2017, 11:14 AM
#7
Rennlist Member
Interesting timing on your post.
I have noticed that my engine's performance......
I did a bit of research ......That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually.
I have noticed that my engine's performance......
I did a bit of research ......That is the boiling frog syndrome. Put the frog in cold water first, then turn up the heat. The frogs stay in the pot until cooked. Same with engine degradation. They don't notice the decline because it occurs gradually.
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10-13-2017, 11:22 AM
#8
Preventative medicine- frequent oil changes and drive it hard on occasion.
10-13-2017, 12:13 PM
#9
Rennlist Member
I used to drive a BMW 335i (N54 engine) that suffered from this.
Before I had the intake valves blasted clean w/ walnut shells, the car would stumble and hesitate at WOT and other high-load situations.
The cost for the cleaning service on one of these BMWs is about $600-$700 depending on the shop (indy vs. dealer). The intake manifold has to be removed to get access to the intake ports on the cylinder head. My guess is that if this service were to be done on a 997.2, the cost would be at least double due to poor physical access and the extra labor involved. It may even be necessary to drop the engine out of the car.
Before I had the intake valves blasted clean w/ walnut shells, the car would stumble and hesitate at WOT and other high-load situations.
The cost for the cleaning service on one of these BMWs is about $600-$700 depending on the shop (indy vs. dealer). The intake manifold has to be removed to get access to the intake ports on the cylinder head. My guess is that if this service were to be done on a 997.2, the cost would be at least double due to poor physical access and the extra labor involved. It may even be necessary to drop the engine out of the car.
10-13-2017, 12:14 PM
#10
Rennlist Member
10-13-2017, 08:08 PM
#11
Not to be a cynic but their value cleaner treatment looks very similar to seafoam spray treatment, you can do this yourself for $10
That plus some detergent fuel additives...
That plus some detergent fuel additives...
10-13-2017, 09:08 PM
#12
I'm with the skeptics. A quick spray has little chance of dissolving deposits. And I've yet to see a documented need on the 9A1 motor. I'm at 103K miles and just got back from a 1200 mile journey involving a lot of non patrolled straights, amazing curves, and massive grades resulting in some major changes in altitude. Ran throughout the rpm range. Never a stumble.
I almost only use Chevron for the Techron, but go to Shell when needed, or others when in the wilderness (Wyoming, Montana = Sinclair).
I almost only use Chevron for the Techron, but go to Shell when needed, or others when in the wilderness (Wyoming, Montana = Sinclair).
10-13-2017, 10:23 PM
#13
Rennlist Member
I had a carbon clean out done on my 2008 GTI, and had before and after photos taken. The funny thing is, there was NO difference in performance. I had it done because the car was at 118k miles and figured I should get it done. I had no power loss, or stumbles etc.
I always ran the car on 91 octane fuel, oil changes every 5k miles. Prior to my current 2009 70k mile C4S, I had a 2009 Targa4 bought with 82k miles and sold at 94k miles. I had a dyno day with the car and other 911's, and the car put out exactly an estimated crank 345hp, exactly where it was supposed to be. That car pulled strong too, and felt like it was making every bit of it's claimed power. To my knowledge that car had no carbon cleaning done on it.
I always ran the car on 91 octane fuel, oil changes every 5k miles. Prior to my current 2009 70k mile C4S, I had a 2009 Targa4 bought with 82k miles and sold at 94k miles. I had a dyno day with the car and other 911's, and the car put out exactly an estimated crank 345hp, exactly where it was supposed to be. That car pulled strong too, and felt like it was making every bit of it's claimed power. To my knowledge that car had no carbon cleaning done on it.
10-13-2017, 11:12 PM
#14
Burning Brakes
The secret sauce of BG products is PEA (Polyetheramine). PEA is carbon cleaner. Invented by Chevron, it's licensed to BG. Chevron markets PEA to the consumer under the trademark Techron. BG markets to industry. The difference is in concentration. BG uses a higher concentration of PEA (hence it's really expensive). BG is meant to be to be used once every 30-40 thousand miles while Techron can be used more frequently.
Edd China on Wheeler Dealers did a similar treatment on an old Jag. If it's good enough for Edd, it's good enough for me.
Edd China on Wheeler Dealers did a similar treatment on an old Jag. If it's good enough for Edd, it's good enough for me.
Last edited by Hula; 10-13-2017 at 11:16 PM. Reason: Weird formating