Scotty,
I own a 2015 Kia k900 v8 with the Tau engine. It's a absolute beast of a car with almost zero issues. I've begun my performance upgrades for it, but I've noticed since the octane boost and the chip it's run richer than a son of a gun. I've also changed the spark plugs at their half life which has added a very audible engine roar to the lower exhaust. The main problem is the fuel trim. When taking off from a low idle, I can hear my intake literally gasping for air. Is there a solution?
Thanks,
Sejong.
well if it started when you modified it, then unmodify it.
Kia's aren't very good to begin with and "You can't get blood out of a stone"
That's not the solution. The power and accelerator response are both superb. It's the intake that's going nuts.
Try acting like a mechanic instead of a critic. Let's find out how to fix this tune.
@mountainmanjoe is not wrong. I wouldn't have recommended you start modifying a Kia. You are going to shorten the life span of a car that already has a predicted short lifespan.
sometimes my inner mechanic is the critic
Lol that's the double problem. It's a fine car and has some excellent value. The engine itself is a wolf. I want it to be a absolute beast.
It's essentially a genesis on a badge at this point. The tau is hyundai, the engine is almost entirely owned now by genesis brand. It's just a low ball genesis with stumpy stickers on it.
You say you've started modifying it. What all has been done? Just the intake?
When you start changing intakes, it becomes very important to pay attention to the MAF size. If you are changing the intake for something that flows better and adds more air, that intake is going to have an increased MAF sensor size. The stock ECM is going to get that information and see all this air coming in that it doesn't know what to do with. To compensate, it is going to dump fuel into the engine to try and get the air/fuel ratio correct. This will lead to a condition where it is running very rich. Running rich means you are not getting all the power out of the engine and you need to lean it out some and make it Stoich.
To correct this problem, there are two routes you can take:
1. Buy a handheld tuner, load your modifications into it, and tweak the parameters yourself.
2. Get a professional dyno tune done.
Depending on other modifications you have, or plan to have, I would recommend option 2. With the car on a dyno, not only could a mechanic like myself easily get the air/fuel ratio fixed but we can also program the car to get the maximum benefit of the added parts.
Now, all that said, let me add this: the Tau V8 is not a brilliant piece of engineering, despite what Ward's may have praised it with. Anyone who has ever worked on one of these motors knows they have notoriously weak piston rings and issues with oil consumption, particularly 2011-2012. Hyundai considers Tau V8 oil consumption of 1 quart per 1k miles "normal". It is not. They built the car you have to compete with the M5 and AMG Mercedes, which it does not, and wanted people to believe it would last as long as hold its value as well, which it does not. The Tau V8 is a luxury car motor. It is not a sports car motor and is not designed to be played with. Hyundai got everything they could out of that engine, so by pushing it farther you are rolling the dice.
I personally would not modify it to be something it isn't. If you plan on driving it hard or racing light to light, expect it to start having issues relatively quickly. I don't know what mileage you are at, but anything over 100k is a dice roll as well.
Just some things to consider before you start spending money on it.
So it doesn't have a maf, it has a MAP, which is a little different, but a little the same. All the lot to be ingested. It's sucking air like a freaking madman right now.
I'm thinking of changing the air filter to a K/N and moving to a more aggressive intake overhaul.
Also thanks for the comments that are constructive. I have considered a dyno tune and other things as well. I'm coming from a shadetree background, so I do have some know how, but I am also screwing with a lot of engineering.
Right now the intake is NOT modified. Since I've added octane and changed the spark plugs it's become a kind of AIR HOG and it's basically drowning in a lack of intake. No matter what I do I can't fix this short of just pulling the air filter or something. That's horrible. I am short on answers right now. I replaced the MAP and I changed all the spark plugs. Everything else is operating at full. It's just guilty for air.
I dunno what to do at at this point.
Thanks!
Also this motor is well under 100k