DI engines: ethanol fuel better?

[Olas]

The easy answer is VTA.

brake cleaner through a vac. line into the inlet manifold should help soften up deposits that are already there.

 

[SteveSRT8]

Originally Posted By: Shannow
auto-ignition is a problem with the GDI cars, and GM/API are working on oils to prevent it.

If you've got oil, and only oil in the end-gasses, near the walls, they can be much more prone to dieseling that when there's fuel mixed with it as well.

There's some papers around that I've linked to before on GDI oil formulation to reduce end gas autoignition.


Some mfgrs have already said they are using both DI and an injector or two for part throttle cylinder filling issues as well. Yet others seem to have great DI engines that have few issues. There's a lot of proprietary tech that is wildly different for platform to platform.

It's got a ways to go yet in some places.

And note that introducing anything into a 'dry' intake is unlikely to evenly reach all the valves especially if it does not enter through the TB...

 

[Cujet]

A bit off topic. Direct injection engines can, with proper design, achieve better BSFC numbers with ethanol in the gasoline. It takes very high compression, careful cam timing, downsizing and turbocharging. But they can achieve "diesel-like" efficiency when compared by BSFC methodology.

For those who don't know, BSFC is "brake specific fuel consumption" BY WEIGHT of the fuel consumed, not by volume.

For example: an engine has a BSFC of 0.5 pounds fuel per hour, per HP produced. (that's also 304 grams of fuel consumed per KWH power produced) or slightly better than a typical Chevy small block (0.55LB/HP/HR)

 

[Shannow]

Sir Harry Ricardo was getting 0.45 lb/hphr back in the 20s, running 5:1 compression ratio with (almost) kerosene as a fuel.

His 200hp tank engine was 186 cu-in (per cylinder, and there were 6 of them)

 

[A_Harman]

Originally Posted By: Cujet
A bit off topic. Direct injection engines can, with proper design, achieve better BSFC numbers with ethanol in the gasoline. It takes very high compression, careful cam timing, downsizing and turbocharging. But they can achieve "diesel-like" efficiency when compared by BSFC methodology.

For those who don't know, BSFC is "brake specific fuel consumption" BY WEIGHT of the fuel consumed, not by volume.

For example: an engine has a BSFC of 0.5 pounds fuel per hour, per HP produced. (that's also 304 grams of fuel consumed per KWH power produced) or slightly better than a typical Chevy small block (0.55LB/HP/HR)


Stated mathematically, BSFC is fuel mass flow divided by Horsepower, and is directly related to the engine's thermal efficiency. A lower number means higher efficiency. I have tested high-performance gasoline engines that have max power BSFC's down to ~.41 lb/hp/hr. Emissions controlled engines pay a penalty in BSFC by having to be tuned over-rich to protect the catalyst from excessive exhaust temperature. Their part-power BSFC's though, are quite good, because they can be tuned to a stoichiometric mixture at road load conditions.

I can't comment on what the BSFC of modern diesels with emissions controls are, but before emissions regulations really got tight, the Detroit Diesel Series 60 was said to be achieving .32 lb/hp/hr. This was in the late 80's to early 90's.

 

[rikstaker]

The intake valve deposit issue has been way overblown. These problems plagued the first DI engines. The newer ones have measures built in to workaround those problems case in point Hyundai's split injection or mazda Skyactiv's heat isolation on the valves to burn off deposits.

If it were such a huge problem you would see a lot of Hyundais mazdas and GMs sputtering breaking down..but no these engines are purring along nicely.

Fuel dilution on the other hand...

 

[Quattro Pete]

Originally Posted By: rikstaker
If it were such a huge problem you would see a lot of Hyundais mazdas and GMs sputtering breaking down..but no these engines are purring along nicely.

DI deposits rarely result in cars just "breaking down." Deposit formation is a slow gradual process that results in some performance reduction. Most people wouldn't be able to easily tell that their car lost 10% of its original performance when that loss was very gradual, spread over 10 or 20 thousand miles.

 

[Lurgi]

My direct injection Hyundai Accent has needed premium fuel since the day it was new and I didn't know it. Apparently, the knock sensor has been causing chronic ignition retard and I didn't know what was going on. I started using premium 4 weeks ago and have documented a 5+ MPG increase on the open road. The best it ever got on 87 octane was 37 MPG. I'm seeing 42.5 MPG now on the open road at moderate speeds (approx. 65 mph.) I just drove 50 miles at an average of about 75 MPH and saw 40.5 MPG, not even trying. The car would never approach 40 MPG before on 87 octane even when I tried my [censored] off.

 

[waltywalt]

Well my 2012 Hyundai veloster at 40,000 miles started knocking. Took it to Hyundai and they said all the Hyundai di engines are having a known issue with carbon build up. And that noise I hear is engine knock. They did a bg 44 fuel induction cleaning and the noise went away. I also noticed the car def had more pep. Sad thing is it was onlyh two weeks ago and now im hearing that sound again. Ps I run top tier fuel 90 percent of the time and have used the tectron cleaner 4 times also . So idk what to think anymore. Ps I run full synthetic oil and change at 3,750 miles because they also told me the di engines tend to dilute with fuel. So all I can say is no matter what you do to try and combat the issues with di engines nothing will work. They are built to have carbon issues.

 

[demarpaint]

Originally Posted By: waltywalt
Well my 2012 Hyundai veloster at 40,000 miles started knocking. Took it to Hyundai and they said all the Hyundai di engines are having a known issue with carbon build up. And that noise I hear is engine knock. They did a bg 44 fuel induction cleaning and the noise went away. I also noticed the car def had more pep. Sad thing is it was onlyh two weeks ago and now im hearing that sound again. Ps I run top tier fuel 90 percent of the time and have used the tectron cleaner 4 times also . So idk what to think anymore. Ps I run full synthetic oil and change at 3,750 miles because they also told me the di engines tend to dilute with fuel. So all I can say is no matter what you do to try and combat the issues with di engines nothing will work. They are built to have carbon issues.


Wow after only 40K miles, I would not be a happy camper. I didn't expect the cleaning treatment the dealer did would do much for any length of time. What are the driving conditions, and what follow up action do they plan if redoing the process they just did doesn't work? Also does anyone know what mods if any to the DI system the 2013's and 2014's have that the 2012 doesn't have?

 

[waltywalt]

Demarpaint I haven't gone back to Hyundai yet and told them but I plan on it in a few days. Whats weird is I just got home from going to the deli and the car wasn't making that noise this morning. I gotta take a ride later this morning and its about an hour trip so I will listen again to see if I hear it. Its a very distinct noise and when the Hyundai tech took a ride with me two weeks ago he said it was 100 percent engine knock caused by carbon build up. So I know the sound. Hopefully the sound doesn't come back. Ps one of the sales reps said Hyundai knows about the issue and might issue a tsb or recall in the near future. I mean lets face it, doing a bg44 induction cleaning shouldn't be considered routine maintenance. When I was at Hyundai I pointed that out to them. I said were in the manual under maintenance does it call for this bg44 service to be done. It doesn't and they really didn't have an answer for me. One guy there did mention that I should sometimes get the car out and romp on sometimes. Clean things out so they say.

 

[waltywalt]

Mostly around town driving with a highway drive once a week. Also I have a feeling with the way the wife lets the car warm up for ten minutes in the winter that it might have something to do with it. But she always has the baby with her so I don't blame her for doing that. I asked one of the techs at Hyundai about a catch can and he said no that it would void the warranty. So without doing that I have no idea how to combat this issue. I guess I can try using tectron every 3000 miles but whats the difference if I gotta pay 130.00 dollars every 40,000 miles anyways. Idk what to think. To be honest I really don't care anymore. Im gonna get rid of the car by September anyways. No more hyundais or di engines for me. HAD ENOUGH.

 

[Cujet]

I have to wonder if the big name brands are doing a better job of engine management with Direct Injection?

Certainly, our 2011 F150 Ecoboost is working wonderfully.

 

[demarpaint]

Originally Posted By: waltywalt
Demarpaint I haven't gone back to Hyundai yet and told them but I plan on it in a few days. Whats weird is I just got home from going to the deli and the car wasn't making that noise this morning. I gotta take a ride later this morning and its about an hour trip so I will listen again to see if I hear it. Its a very distinct noise and when the Hyundai tech took a ride with me two weeks ago he said it was 100 percent engine knock caused by carbon build up. So I know the sound. Hopefully the sound doesn't come back. Ps one of the sales reps said Hyundai knows about the issue and might issue a tsb or recall in the near future. I mean lets face it, doing a bg44 induction cleaning shouldn't be considered routine maintenance. When I was at Hyundai I pointed that out to them. I said were in the manual under maintenance does it call for this bg44 service to be done. It doesn't and they really didn't have an answer for me. One guy there did mention that I should sometimes get the car out and romp on sometimes. Clean things out so they say.


I hear ya. 40K and an induction cleaning shouldn't be routine maintenance. In fact it should be free even if out of warranty. It is clearly a design issue and IMO a lot of these mfgs. still don't have it ironed out. I'd love to know what improvements they made if any for the newer models.

What sucks is you haven't really driven that much to know if the cleaning will be effective for any length of time.

 

[wemay]

Sorry to hear waltywalt. Before the Santa Fe Sport 2.0T, we had a '12 Veloster (non-turbo, manual shift). Also ran Top Tier (87 octane) but only used conventional oil, also at 3700 mile oci. We traded the car in with over 70K miles and had 0 issues. I wonder how hit or miss this issue may be. So far, 0 issues with the SFS as well.

 

[badtlc]

Originally Posted By: TiredTrucker
I have been convinced for some time, that no matter the design, there is always some oil, condensation, etc making its way thru the PCV line to the intake manifold. If you get on any number of the performance car forums, and several truck forums, installing a PCV oil catch can is the cat's meow for keeping the stuff from making it to the intake and building up on intake valves and increasing deposits in the combustion chamber. Also, oil and other particulate in the combustion chamber can lower the overall octane rating of the fuel in the burn. This is known from performance engines.

I installed on on my 2013 5.3L and in roughly 10,000 miles, it captured about 1/2 quart of oil and gunk that would have made it to the intake. In that 10,000 mile interval, the engine used a total of about 2/3 quart of oil.

I am convinced that the first line of defense with a DI engine is keeping any crankcase residues and particulates from getting to the intake. A PCV oil separator catch can would do more than anything else as a proactive measure. It would greatly reduce the intake deposits and reduce the risks of lowering octane in the combustion chamber and knock.


Catch cans have been shown to do nothing for intake valve deposit prevention. That is not the purpose of a catch can anyway.

 

[waltywalt]

Well had the car out on the highway for about an hour lastnight. I figured id try the Italian tune up everyone seems to think works. It didn't. My v is knocking At 1800 to 2000 rpm under load. Gonna call Hyundai today and ask them whats up.

 

[waltywalt]

If Hyundai thinks im paying for the fuel system cleaning again there high. Im trying to be calm but this is getting old.

 

[Lurgi]

I give my GDI Accent regular Italian tune-ups. They don't seem to "blow out" or "clean out" anything. The [censored] thing continued to ping no matter what. I religiously ran only top tier gas since it was new. I used 87 octane only as well, since the owner's manual states that is OK. Finally, since the pinging was slowly worsening, I decided to try premium fuel only. The ping has almost completely stopped. And the fuel economy has picked up over 5 MPG! on the highway. Using premium is actually quite a bit cheaper with this sort of improvement in economy. And the engine isn't beating itself to death. I would say when it was pinging bad on 87 octane, the knock sensor influenced the computer to take out timing, and I noticed downshifting, apparently to stop the pinging.
Is your car knocking or is it pinging? Are you running premium fuel currently?
The only worry I have is that eventually my car will have carbon build up so bad that it won't even operate on premium any more.

 

[demarpaint]

Originally Posted By: Lurgi

The only worry I have is that eventually my car will have carbon build up so bad that it won't even operate on premium any more.


I have a feeling you're probably right. The technology is evolving, unfortunately a lot of people who got in early on DI are going to eventually have problems with it.