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Why Carbon Build-up
The conventional wisdom is that we should reasonably frequently high-rev the Renesis rotary to "blow out the carbon". I like to high-rev this terrific engine for fun, but why the need to blow out carbon? What is the difference between burning fuel in a rotary and burning it in a reciprocating piston engine that makes it produce carbon which has to be regularly blown out in the one, but not the other?
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You can read around and find many references to this, but in a nutshell, the rotary requires a richer air to fuel mixture (10-14 to 1) than a piston engine (that mostly stays at stoich, 14.7 to 1).
This rich fuel mixture causes most of it - in addition the rotary has some oil injection for seal lubrication and this will add to it a little. |
Originally Posted by Jax_RX8
(Post 2315194)
You can read around and find many references to this, but in a nutshell, the rotary requires a richer air to fuel mixture (10-14 to 1) than a piston engine (that mostly stays at stoich, 14.7 to 1).
This rich fuel mixture causes most of it - in addition the rotary has some oil injection for seal lubrication and this will add to it a little. |
We get alot of carbon from the oil metering system. There are 2 oil injection nozzles on each rotor housing. This supplies a very small amount of metered oil into the system to lubricate the apex seals. The nozzles on the Renesis are actually aimes towards the outsides of the rotors. They are also trying to lubricate the corner seals which now see hot exhaust gasses and have different wear characteristics from older non side exhaust port engine corner seals. Since alot of this oil goes towards the sides of the rotors, it doesn't get burned. The hot gasses of combustion do not get to the sides of the rotors. This carbon buildup is more of a problem on the Renesis than the older rotaries as they did not direct most of the oil injection towards the sides of the rotors. Carbon does still build up on the rotor faces as well.
We want to get rid of this carbon. It can do a number of things. Carbon buildup can lead to unstable combustion as it physically takes up space in the engine and it's rough texture can lead to flame propagation issues and internal airflow during combustion. Carbon also holds alot of heat. It is due to high carbon buildup that old car engines will "diesel" and keep running after being shut off. This hot carbon can spontaneously ignite whatever is in the engine. We don't want this to happen. We only want the spark plug to do that. It can also lead to detonation while running. The carbon that builds up on the sides has a tendency to collect on the ports. This affects airflow into and out of the engine. It can also cause seal breakage in severe cases. Seals can get stuck down in their grooves and in extreme cases an engine could carbon lock. Carbon holding seals could lead to low compression. Overall it's a bad thing and we don't want it in our engines. |
Also remember the rotors turn 1/3rd the speed of the shaft. Taking it to 9000rpm to clear it out is like clearing out a piston engine by reving it to 3000rpm:lol:
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There's far more to it than the 1/3rd argument. Keep in mind in a piston engine you are trying to get carbon to go up to get out of the engine and are relying on exhaust velocity to pull it out. In a rotary we can at least physically scrape it across the exhaust ports. Pistons change direction. Rotors don't. Piston engines (modern 4 stroke car engines) don't inject oil into the combustion chamber. There are definitely pros and cons for each engine when it comes to it.
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Keeping on the echoing and hopefully clarifying some of rotarygod's message theme; carbon build up is not just an issue on rotaries. Conventional piston engines can also have carbon build up. One piston engines, carbon tends to be either on top of the piston and on the backside of the valves. This is the basis behind the "Italian tune-up", i.e. running an engine hard will sometimes smooth it out as the carbon that was built up gets blown out. Older piston engined cars really did require the occasional redlining, but with modern computers the air-fuel mixture is much better controlled and so this is not as big of an issue. However, there are still situations where the computer will run fairly rich AF ratios (Subaru boxers for example, love doing this, even on the normally aspirated units) and so contribute to carbon build up. It's good to occasionally redline a piston engined car as well!
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Slight segway to the above post on redlining the engine. In order to blow-out the carbon one must be in WOT. Not just let it lazily rise to redline.
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OK, I am going to ask a question that may get me flamed, but idk...how good are the fuel additives, such as Chevron Techron, at removing carbon build up? I know some ppl love the BG44k, but are other fuel additives effective?
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Still somewhat confused about it all myself. 2 exhaust ports, 2 primary intake ports, 2 secondary intake ports, and 2 auxiliary intake ports. How each fits into the magical rpm 'ranges' I still don't fully understand.
Another thread indicated to me the following: SSV opens @ 3750 VFAD opens @ 5500 APV opens @ 6000 VDI opens @ 7250 Now just how this four items 'fit' into the whole 6 port thing (on a 06 or later) rotary is still...I'm afraid a mystery to me. Plus toss in the WOT that seems to be needed....and long timers on the site wonder how us newbies can get confused. |
Thanks for the comments - rich fuel/ air mixture + oil does sound like a carbon recipe. One wonders why the carbon caution and advice to high-rev is not in the owner's manual. Seems as though it should be.
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Oh but it is. When you get your 8 you get a small three page book that states;"And remember Rotarys like to beep. So beep everyday!" :)
-Gil |
I never got that!!! Must be a US thing (I'm in Australia).
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Originally Posted by rxtreme
(Post 2316239)
OK, I am going to ask a question that may get me flamed, but idk...how good are the fuel additives, such as Chevron Techron, at removing carbon build up? I know some ppl love the BG44k, but are other fuel additives effective?
Next up is Techron, Gumout Regane, and Redline SI-1, which are all PolyEthylAmine (PEA) based fuel system cleaners. PEA was developed by Chevron and is sold to several companies for their use - it is also used in Chevron/Texaco gasoline. These are all good at removing built up carbon. Most of the rest are very mild cleaners, mostly kerosene based. Can be useful, but not nearly as effective as the ones listed above. Now for the catch - all the cleaners listed above when in use, will hurt your oil film from your OMP injection and/or premix - that is why they should be used sparingly, because higher wear will occur during use. That is also why I always suggest continuous use of a lubricious cleaner that does dissolve or break down carbon, like FP Plus, FP60, MMO, or Lucas UCL. These will provide continuous cleaning and add some lubricity, WITHOUT impacting your oil film from your OMP oil/premix. Note though that Lucas UCL should be used alone in your fuel (if you like this product) as it does not seem to mix well with other 2-cycles - the others will all mix well with other premixes if you so choose. |
Man, I had a dream last night that when I shut my car off it still continued running for awhile and was dieseling. I was kind of freaked out by the thought of all that carbon build-up!
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I just put a bottle of Techron (the one for 20 gallon one), cost me 11 bux :(, with 4oz Premix cuz I know that Techron will clean my OMP stuff out. and I dont want that.
Then I got 5 bottles of Prestone Complete Fuel system cleaner, 7 bux each. for my next 5 tanks of gas (or maybe 1 after another) I want to get REdline but Autozone does not sell them, and Im lazy to order it online :( |
Originally Posted by LionZoo
(Post 2317494)
Man, I had a dream last night that when I shut my car off it still continued running for awhile and was dieseling. I was kind of freaked out by the thought of all that carbon build-up!
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Originally Posted by Shrapnel
(Post 2316983)
I never got that!!! Must be a US thing (I'm in Australia).
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Originally Posted by Jax_RX8
(Post 2317138)
BG44k is the best cleaner out there - very strong.
Next up is Techron, Gumout Regane, and Redline SI-1, which are all PolyEthylAmine (PEA) based fuel system cleaners. PEA was developed by Chevron and is sold to several companies for their use - it is also used in Chevron/Texaco gasoline. These are all good at removing built up carbon. Most of the rest are very mild cleaners, mostly kerosene based. Can be useful, but not nearly as effective as the ones listed above. Now for the catch - all the cleaners listed above when in use, will hurt your oil film from your OMP injection and/or premix - that is why they should be used sparingly, because higher wear will occur during use. That is also why I always suggest continuous use of a lubricious cleaner that does dissolve or break down carbon, like FP Plus, FP60, MMO, or Lucas UCL. These will provide continuous cleaning and add some lubricity, WITHOUT impacting your oil film from your OMP oil/premix. Note though that Lucas UCL should be used alone in your fuel (if you like this product) as it does not seem to mix well with other 2-cycles - the others will all mix well with other premixes if you so choose. btw, thanks for answering my pms.. would it be better to skip premix when running 44k???? the whole glop issue is a concern of mine.. :) as in i am 500miles from 44k and beat the f out of my car!!!!! beers :beer: |
OK, I can clearly see how the carbon cooks up through the combo of oil and rich mixture. But can some tech-savvy please explain why normal cruising around lets the carbon build up? I mean, why aren't the flames and the pressures in the working chambers at low or mid-revs (which must be pretty powerful, lets face it) enough to blow the crap out? After all, at high revs you're using MORE fuel and MORE oil, thus creating even MORE carbon. I shouldn't think about it, coz its driving me nuts. :Eyecrazy:
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Originally Posted by swoope
(Post 2322635)
would it be better to skip premix when running 44k???? the whole glop issue is a concern of mine.. :) as in i am 500miles from 44k and beat the f out of my car!!!!!
beers :beer: - 44k alone in the fuel (no premix) will likely give you a little better cleaning out, but with some sacrificial wear (albeit for only one tank). You would still have some oil from the OMP coming in, so the additional wear should be minimal (of course very slow wear is happening all the time, so you are slightly increasing the wear rate for the one tank that the cleaner is in use). - If you would like to clean but want to minimize any wear impacts, then you can mix in your normal premix as well - you will just have slightly more carbon generation during this tank that will slightly reduce the cleaning gains. The key is not to use a non-lubricious cleaner very often - no more than once every 5000 miles - and hopefully use a lubricious cleaner in every tank so that the need for this additional cleaning is reduced and is performed even less often (say every 15k or so). End of a long answer - personally, I would go ahead and add my premix as well. |
Originally Posted by Jax_RX8
(Post 2322859)
Depends on you priority:
- 44k alone in the fuel (no premix) will likely give you a little better cleaning out, but with some sacrificial wear (albeit for only one tank). You would still have some oil from the OMP coming in, so the additional wear should be minimal (of course very slow wear is happening all the time, so you are slightly increasing the wear rate for the one tank that the cleaner is in use). - If you would like to clean but want to minimize any wear impacts, then you can mix in your normal premix as well - you will just have slightly more carbon generation during this tank that will slightly reduce the cleaning gains. The key is not to use a non-lubricious cleaner very often - no more than once every 5000 miles - and hopefully use a lubricious cleaner in every tank so that the need for this additional cleaning is reduced and is performed even less often (say every 15k or so). End of a long answer - personally, I would go ahead and add my premix as well. will order some fp plus this weekend.. jax thanks for all the great info.. when you make it to orlando the cocktails are one me!!!!!! ;) beers :beer: |
so do you guys take it real easy with the 44k in it? or do you drive more "beepy" with it in the tank?
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Originally Posted by AE92
(Post 2786918)
so do you guys take it real easy with the 44k in it? or do you drive more "beepy" with it in the tank?
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Here is a question, I put a complete fuel system cleaner in almost every month, says every so many miles but I disregard that, been doing it for about 5 months owned the car for 8 months, is this doing me any good with the carbon?
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Re-Amemiya hi power jet G (Liqui-Moly. cleaning and coating) will do the best job but lack of people knows the real trick to get the best results. I use BG44k once. After finish the mixed tank for long cruising, finished another tank (without premix), felt the change when using the 3rd tank (with premix 250:1) on the next morning. Just like when it was new. Only thing happen on the BG44k mixed tank was CEL came out and said system too rich, for 3-4 times. I ignored it and just continue with average 5k rpm (I did some redline of cause, to clean up the 3rd set of injectors a bit on my 6 ports). BTW, before that, I did took out my inlet manifold and clean up with WD40 (fast and cheap). Same to the throttle body.
http://www.re-amemiya.co.jp/hi_power_jet_g/ |
Originally Posted by AAChaoshand
(Post 2787031)
Here is a question, I put a complete fuel system cleaner in almost every month, says every so many miles but I disregard that, been doing it for about 5 months owned the car for 8 months, is this doing me any good with the carbon?
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Originally Posted by robrecht
(Post 2787234)
The more you use it, the more increased wear in your engine.
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just run water though the engine once in a while.
I had carbon buildup around the ports the most. Look at the port on the bottom where it narrows: http://img.ircimages.com/ircimages/6...3a228d0cfd.jpg |
Where is the best place to buy the 44k?
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Originally Posted by 9krpmrx8
(Post 2787302)
Where is the best place to buy the 44k?
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may be a dumb question but in what gear is it best to red line it for the carbon buildup?
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Originally Posted by lokaldisruption
(Post 2787336)
may be a dumb question but in what gear is it best to red line it for the carbon buildup?
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Originally Posted by nuke0907
(Post 2787338)
try to do it in 6th. :lol:
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i have an AT but around 50mph in 1st and 80mph in 2nd. i don't know after that.
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Originally Posted by nuke0907
(Post 2787354)
i have an AT but around 50mph in 1st and 80mph in 2nd. i don't know after that.
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Originally Posted by lokaldisruption
(Post 2787357)
i think your missing out on the full effect fof the 8
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so fuel system cleaners actually harm your engine if used more than they should be? I know Shell gas has a fuel cleaner in it, well V power 93 octane anyways, and thats what I mainly fill up on.
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Originally Posted by AAChaoshand
(Post 2787568)
so fuel system cleaners actually harm your engine if used more than they should be? I know Shell gas has a fuel cleaner in it, well V power 93 octane anyways, and thats what I mainly fill up on.
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Originally Posted by nuke0907
(Post 2787329)
i've seen it at all the local auto parts stores.
odd most of the time you have to go to a dealership.. but you might ask charles hill. he might have some. i just finished a cleaning. mpg back up in the low 20s from the 18s. beers :beer: |
I've been following these forums for a while, and have seen a lot of discussions for oil synthetics and oil/fuel additives. It is true that most fuel additives/cleaners that are popular on the market can actually be harmful to the engine if used too frequent as their nature is to be a "one use" product.
There is a company in the U.S. that sells a fuel additive and oil additive that is to consumers in the U.S. The product is called eeFuel (fuel additive) and eeLube (oil additive). I've come to know both of these products fairly well as I work for the company. While I am not the scientists that developed the product by any stretch of the imagination, I can confidently say this is just about the best fuel and oil additive combination you could use in the U.S. It does what other additives claim to do, but significantly better. The fuel additive itself increase MPG (by up to 25%), reduce emissions (by up to 50%) and extend engine life. The product, unlike any other fuel additive out there, is based on liquid nanotechnology. The core purpose of the product is to perfect the combustion cycle of any gasoline, diesel or combustible fuel engine. It reduces the octane requirement of any engine significantly and also cleans away carbon deposits of the engine in a soft efficient manner (By doing this, it does not harm the engine long-term, and will keep the engine in clean and in tip-top shape with continual use) . It does all this by using nanotechnology by creating more efficient fuel/air mixture in the combustion chamber with millions of tiny steam explosions. While I may have just sounded I know what I am talking about about, I've just heard it a million times and have picked it up. All I can tell you is the results that I see in my current vehicle. In my 2005 Nissan Altima V6 I've gone from 320 miles per tank up to around 400 miles per tank on a consistant everage. Not to mention there is a noticeable performance increase of the vehicle (seems to have more noticeable "pep") and an overall much smoother/quiter sounding engine at idle. If you have not already gotten bored by my post, I want to say I've been looking to purchase an RX-8 over the next few months. I've always wanted to know what kind of increase in performance and mileage these additives would give in an RX-8, due to it's unique rotary additive. I also am curious on how the oil additive helps with the constant checking of the oil the the RX-8 requires. If anyone wants to try them out and perhaps document MPG/Performance increases, let me know. For more information about the company and their products, check http://www.eefuelsales.com Hope my post wasn't too long :uhh: |
oh my God.
OD |
Originally Posted by iservealot
(Post 2787673)
The fuel additive itself increase MPG (by up to 25%), reduce emissions (by up to 50%) and extend engine life.
Hope my post wasn't too long :uhh: 2 posts, sounds like a spammer. |
Originally Posted by iservealot
(Post 2787673)
While I may have just sounded I know what I am talking about about ...
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Spam is for eggs. Not Message Boards
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Originally Posted by iservealot
(Post 2787673)
I've been following these forums for a while, and have seen a lot of discussions for oil synthetics and oil/fuel additives. It is true that most fuel additives/cleaners that are popular on the market can actually be harmful to the engine if used too frequent as their nature is to be a "one use" product.
There is a company in the U.S. that sells a fuel additive and oil additive that is to consumers in the U.S. The product is called eeFuel (fuel additive) and eeLube (oil additive). I've come to know both of these products fairly well as I work for the company as a Technology Director. While I am not the scientists that developed the product by any stretch of the imagination, I can confidently say this is just about the best fuel and oil additive combination you could use in the U.S. It does what other additives claim to do, but significantly better. The fuel additive itself increase MPG (by up to 25%), reduce emissions (by up to 50%) and extend engine life. The product, unlike any other fuel additive out there, is based on liquid nanotechnology. The core purpose of the product is to perfect the combustion cycle of any gasoline, diesel or combustible fuel engine. It reduces the octane requirement of any engine significantly and also cleans away carbon deposits of the engine in a soft efficient manner (By doing this, it does not harm the engine long-term, and will keep the engine in clean and in tip-top shape with continual use) . It does all this by using nanotechnology by creating more efficient fuel/air mixture in the combustion chamber with millions of tiny steam explosions. While I may have just sounded I know what I am talking about about, I've just heard it a million times and have picked it up. All I can tell you is the results that I see in my current vehicle. In my 2005 Nissan Altima V6 I've gone from 320 miles per tank up to around 400 miles per tank on a consistant everage. Not to mention there is a noticeable performance increase of the vehicle (seems to have more noticeable "pep") and an overall much smoother/quiter sounding engine at idle. If you have not already gotten bored by my post, I want to say I've been looking to purchase an RX-8 over the next few months. I've always wanted to know what kind of increase in performance and mileage these additives would give in an RX-8, due to it's unique rotary additive. I also am curious on how the oil additive helps with the constant checking of the oil the the RX-8 requires. If anyone wants to try them out and perhaps document MPG/Performance increases, let me know. For more information about the company and their products, check http://www.eefuelsales.com Hope my post wasn't too long :uhh: after 4 years get back to us... till then piss off.. oh and have a great new year.. gw. :) beers :beer: |
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It almost sounds..... impossible.
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man, a company saying its product works amazingly well?
thats so believable! anyone want to buy some sr motorsport pullies? you gain 22whp with them. |
Originally Posted by swoope
(Post 2787795)
get the rx8. and chart you mpg..
after 4 years get back to us... till then piss off.. oh and have a great new year.. gw. :) beers :beer: Well to be honest, I can see how this would come off as spam. The truth is that I have been following a lot of threads on this forum for quite a while now and until now, have never really needed to interject. My apologies if this came off as spam, my intentions were not so. The numbers I posted above are realistic numbers, and if anyone would to take time to look over any independent testing, they would see pretty high increases in mileage and decreases in emissions (for an additive). Obviously I can't show you numbers for an RX-8, and I don't own one. ...that's why I am posting here. |
Few days ago my car get flooded so there is any chance for carbon build up in the car and how i can understand weather the carbon is build up or not?
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