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> The New Kia Optima GT 2017 thread, Strictly for discussion about the car

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constant_weight
post Jul 8 2017, 08:27 AM

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Review from US, this one is professionally done. The best review I've seen in years.



This post has been edited by constant_weight: Jul 8 2017, 09:56 PM
constant_weight
post Jul 9 2017, 11:25 AM

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QUOTE(sitescope @ Jul 9 2017, 09:43 AM)
This gt is slower a bit than elanTurbo
Izit bcoz of weight ?
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Not only power to weight ratio, it has to do with the gear ratio and DCT shift faster. ESport has more shorter gear 1,2,3 like I said in the ESport thread. ESport is faster than OGT up to about 120kph only. OGT only go into gear 3 past 90kph and gear 3 all the way to 150!

So OGT would much faster from 100-200+.

Under full load with 5 adults, I believe OGT will be faster 0-100 with its significantly higher torque. But that have to wait you buy OGT first we come up test together with my ESport. Sign, still waiting for my car.

Put videos below side by side, you will see what I described. Elantra Sport to 200 is slower, not one can break the law of physics, Hahaha.

Elantra Sport
https://www.youtube.com/watch?v=psmQFH0rz6g

Optima GT
https://www.youtube.com/watch?v=Qs0jrrie9ZE

I won't too caught up with the power of point something second different, enjoy the car is most important. Seating position not suitable, cheapest+fastest+best quality also no use, back pain after long journey, not that young anymore.

This post has been edited by constant_weight: Jul 9 2017, 11:29 AM
constant_weight
post Dec 24 2017, 07:39 PM

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QUOTE(pds_disi @ Dec 24 2017, 06:29 PM)
Owned a Forte 1.6 high spec for 6 years, thinking of upgrading, too bad 240hp is out of my budget  bye.gif , maybe 200hp is more feasible.
Now eying Elantra 200hp, but still wanna wait for Kia version of the same car, since both company abang adik, hope we will see a 200hp kia soon.

My experience with korean car are not bad, and plenty of jewtube reviewer from western country seems to agree so.
So thanks to those basher, i can effort better car for a more reasonable price.
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Kia version is the cerato coupe.

Own Elantra Sport since launch. First batch buyer. The biggest down side one once drive this car can't go back to Japanese car of C and D segment except Mazda. Next upgrade few years down the road probably a VW Passat 2.0T or Genesis G70, maybe Elantra N/i30N or a GTi. See how family grows first, and hopefully Hyundai bring in the interesting models...hahaha
constant_weight
post Dec 29 2017, 04:34 PM

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QUOTE(wkc5657 @ Dec 29 2017, 03:34 PM)
That's how most car makes market their turbocharged car, more fuel efficient and yet powerful. But the thermodynamic efficiency didn't improve much, so layman physics still governs : more power = more petrol

Simple, but still a lot can't seem to accept/understand.
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The termo efficiency of a turbocharged engine is better than NA engine. But this efficiency is at kW/L, which means you get more power per liter of fuel not how far you travel. People tends for forget this part.

For a lot of idling and constant speed cruising, the fuel economy will be slightly better (couple of percent at best) than NA engine of same capacity due to reduction of pumping loss of turbocharged engine (more on this later).

For hard driving that max out the power, of course it use more petrol than NA engine with equivalent capacity. Imagine additional of 0.5 bar on a 2.0L = 2.0L with 1.5x the pressure (Boyle's law) = 1.5x the oyxgen (Dalton's law). Probably more efficient of kW/L comparing to a 3.0 NA engine, total fuel usage disregards of power for sure more than 2.0 NA.

About the pumping loss, the exhaust valve open before the bottom dead center of the combustion phase. After BDC and into the exhaust phase, most of the air already escaped from cylinder. If we let the piston push the air out after BDC like the high school text book, that's a lot of pumping loss and counter productive. The exhaust gas is still very energetic (the reason even the best best ICE has just over 40% thermal efficiency), and used to drive the turbocharger, which in turn reduce the pumping loss at intake with air being pushed in instead of letting the piston suck on the vacuum to pull the air in.

How much boost to maintain is the art of guessing of driver intension base on throttle position, just like how TCU guess the up/down shift. Wastegate open too frequent, driver complains no power and turbolag. Wastegate close too frequent, driver complains high FC. If the programmer so good at machine learning algorithm, he will go predict stock price instead of one damn actuator, hahaha.

This post has been edited by constant_weight: Dec 29 2017, 04:45 PM
constant_weight
post Dec 31 2017, 03:28 PM

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QUOTE(wkc5657 @ Dec 29 2017, 08:25 PM)
Thanks for the technical explanation. My comments on blue. I'm can't explain in technical detail like you do, but from some basic tuning understanding. So please do correct me if i'm wrong again.
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1) Less spinning mess and also overall less surface contact area of pistons to cylinders wall for smaller engine size. I'm not mechanical engineer, but from most article I read the surface area play a bigger role.

2) Modern small turbo engine is almost certainly coupled with direct injection. Temperature is not an issue for idle/low engine load as the fuel is injected at the compression stroke at very lean ratio. Just a small pop at the middle of the combustion chamber away from the cylinder wall. At high engine load, the fuel is injected at intake stroke just like port injection and it has to be rich anyway to prevent knocking.

Beside richer fuel, another technique to reduce the combustion temperature is EGR. Interesting thing is Hyundai/Kia implemented EGR without EGR valves. Just a slight tweak of VVT to open exhaust valve late closer to BDC and also close it late past the TDC to retain some exhaust in the cylinder. Pretty smart tricks to make use of the Dual CVVT and no need to worry the clogged EGR valve maintenance and its contamination to intake side. [see the partial load chart]

3) Not too sure. Maybe the tiny turbo limitation play a role too. Very fast spin up, but reach its capacity limit. Bigger turbo circulate more air volume (more CFM) given the same boost pressure. Each turbo has an efficient flow rate zone, since the primary objective is improve the overall engine thermal efficiency. This is my opinion and without spending couple of weeks to self study volumetric flow rate. I'm not mechanical background, lol.

Attached Image

This post has been edited by constant_weight: Jan 1 2018, 01:49 AM
constant_weight
post Jan 1 2018, 11:49 PM

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QUOTE(wkc5657 @ Jan 1 2018, 09:24 PM)
From how you described hyundai/kia's EGR, the implementation seems more focused towards emissions control. Because, logic states that the cylinder temperature will still remain high and some flame propagation can travel past exhaust valves. The reverse is also usually how most cars heat up the catalytic converter (coupled with richer fuel mix) during cold starts (also the reason why newer engine designs have the catalytic converter placed so close towards the exhaust headers), by advancing exhaust valve opening and/or delaying exhaust valve closure.

For cylinder temperature, EGR will go through a separate loop for cooling, hence the feature some manufacturers use as "cooled EGR".

Here's a little something regarding low speed pre ignition :
http://www.infineuminsight.com/insight/jun...t-auto-ignition
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1) Cooled EGR is only possible with EGR valve based solution and impossible for VVT based EGR.

EGR is only for partly load situation where most of our driving happens (refer to the chart, case 2). Regardless cam based internal EGR or dedicated EGR valve, EGR is disabled for both idling and high load situation. I think it is a smart cost saving implementation/workaround, that is good enough for average foes with compromises, which also has a side benefit of cheaper maintenance. wink.gif

I'm sure coolant cooled EGR is performance superior due to additional cooling but with the drawback of additional heat exchanger and EGR valve that subject to blockage.

2) At Low Speed/Low Load, there is no EGR but still cylinder temperature will not be an issue with direct injection. Low Speed/Low Load is where Stratified combustion happens. FSI - Fuel Stratified Injection by VW/AUDI is referring to this. The fuel injected during compression phase at ultra lean ratio like crazy 40:1 (different manufacturer claims different number). It is injected late and fast just around the spark plugs so the fuel has little chance to mix with most of the air. So it only give a small "pop", most of the air doesn't even react with combustion and will absorb the energy to cool the cylinder down.

I guess that explains why the downsizing turbo engine always coupled with direct injection, a magic combo for fuel economy - tiny turbo to provide low end torque to keep rpm low -> the high available torque at low rpm means relatively load most of the time -> maximize FSI, minimize homogeneous combustion -> sipping minimal fuel.

Maybe the power is just a byproduct of fuel saving effort, once at mid load out of the FSI operating rpm, our tiny turbo car starts gulping fuel. sweat.gif

Low Speed/High Load is something I'm not familiar. So far only experienced it once over 10 years ago in an old carbureted 1.3L corolla during steep high climb. The rpm won't get past 3.5K and gradually dropping even I floored the throttle. Maybe this is the reason for good old advise - don't lug the engine, always downshift, pull up the rpm when need power. To avoid low speed/high load where LSPI happens.
constant_weight
post Jan 2 2018, 12:18 AM

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QUOTE(statikinetic @ Jan 1 2018, 08:42 PM)
Agree. I suspect it may creep higher.
So talking about FC for cars in this segment may be a little off.

A big part of FC is size and weight, not just the engine. The D segment cars are big. The Optima GT is almost 5 meters long and almost 2 meters wide.
In terms of weight, it is also a bit on the heavier side. Taking this into account and looking at the numbers, I'm quite happy with it.
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What is your average speed at the trip computer?

I notice for my elantra sport, it is the clear indicator of my fuel economy. The in more traffic jam, the average speed drops and my L/100km goes up.

So far my benchmark average is 32-34km/h, and get 7.2-7.3L/100km from real refuel. When I have 30-32km/h average, fc will increase to 7.6L/100km. I should get 7.0L/100km for last week due to less traffic as most people was clearing leaves.

My trip computer sticks at 6.9L/100km dominated by long period average as I haven't reset for long time. BTW you can hold OK button for few seconds to reset the fuel economy. Maybe your 10L comes from past aggressive driving? What's your daily summary tell when you shut the car at end of the day? This should be fluctuates base on your driving condition for the day. Optima GT should have the similar system that auto calculate daily summary, yours is color + bigger size.

My worst daily average was 11L/100km when I took 3 giant size Americans around down town. 2 of them at the back struggled with the head room of the fastback roofline.

Now I learned to offset my trip computer report, the number ia generally 0.2-0.3L/100km lower than actual refuel.

This post has been edited by constant_weight: Jan 2 2018, 12:23 AM
constant_weight
post Jan 2 2018, 04:09 PM

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QUOTE(statikinetic @ Jan 2 2018, 09:28 AM)
Average speed is around 25 ish. Larger CC engine together with an extra 200kgs compared to the Elantra had an effect on FC so I don't think I'll see your kind of numbers. Mine is currently at 9.8L/100km and climbing as I started off with a long distance drive. Which gave me a very low FC benchmark to start off.

Am not too worried about it, range between fill ups is around 600km for me. What's more important is that the car doesn't feel lethargic.

Driving home after work is a hoot!
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Oh, only 25. So you definately in more traffic jam than me. If I get 25, I'll probably in 8L+ or even 9L range.

So don't feels bad. Your FC is very good for 25km/h average, and 200kg extra.

Only car with start-stop and hybrid do well in that kind of traffic jam.
constant_weight
post Jan 10 2018, 07:28 PM

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QUOTE(izputra @ Jan 10 2018, 05:18 PM)
Yupp..the 8-speed tranny as in the Stinger is so much anticipated. Also got rumours that Albert Biermann wants Kia 2.0TGDI engine to produce at least 280HP..i'm not sure whether this sort of power will come with the new engine or just retune their current engine.
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Either 8 speed torque converter auto in Stinger/G70, or there is a 8 speed DCT wet clutch that can support 450nm+ completed the R&D and testing. They haven't disclose which car will get this new DCT yet. The future is interesting.
constant_weight
post Jan 10 2018, 07:36 PM

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QUOTE(sitescope @ Jan 10 2018, 05:30 PM)
How come this stock op gt hit 6.7s ?
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Turbocharged engine output varies, and super sensitive to temperature. Manufacturer can choose to quote best case, average, or worst case scenario.

You would get 1 second different if you do your sprint early morning at 23-24C vs noon at 33-34C. You can also splash ice water at FMIC before your sprint.

Also speedometer is faster than real speed. Usually 5km/h for most modern car. So if you measured using speedometer, you probably do 0-95 realistically. If you get GPS racing instrument, you would get different time.

Also for human the average reaction time from vision -> brain process information -> action is 0.4s. All athletes have a clock in their brain to start base on own timing through training. If wait for signal, it is too slow. When they screw up, they get false start.

I think today 0-100 is a bit pointless, 0-200 is more realistic and reflect real world usage. Especially 80 - 140 acceleration which most people would use in day to day driving.

This post has been edited by constant_weight: Jan 10 2018, 07:51 PM
constant_weight
post Jan 11 2018, 08:27 AM

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QUOTE(statikinetic @ Jan 10 2018, 11:13 PM)
It's down to the transmission. The reason the Passat gets to 100km/h quicker is down to the quick shifts from the DSG, while the GT's normal 6 speeder shifts slower. Now I am not saying that the GT's trasmission is slow, but compare it against the DSG and it will feel slow. Take out the gear shifts, focus on 'in gear acceleration' which is what drivers feel when the car kicks off, the GT is just as fast as the Passat. They both put out 350Nm of torque. Make no mistake, the Passat is great to drive as well and I can see both cars being able to keep up with each other on a high speed drive.

So, why did Kia go for a normal 6 speed auto instead of a fancy sports lightning-quick shifter? Reliability. This car is not tuned for the racetrack but as a GT cruiser. Look at it's torque mapping. Hence, it is not meant to win drag races but to provide the driver with a better driving experience across long distances. Gearbox reliability factors very high into the list of considerations when you are building your brand as the last thing you want are reliability issues. Between shaving 1.5 secs off the century sprint and better reliability, which will you pick for your daily driver? Sure, you get to be a sec quicker at the traffic lights, but there's no substitute having your car in the workshop with gearbox issues.

I had the budget to get either the Optima GT or the B8 Passat Highline. Sometimes the most important factor when buying a car isn't on the spec sheet.
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Torque converter doesn't mean it must be more reliable. It all down to the engineered design limit. 10 years back we have Acura 2nd gear pop out for MT, recently Type-R gear grinding gate that upset the fans. Even MT can be screwed up.

My take is at the time of Optima GT design, Hyundai/Kia doesn't have suitable DCT ready. The 7 speed DCT is designed for max of 340nm, not enough.

The 6 speeder torque converter AT is designed for 365nm. Although this seems to be conservative number by Hyundai Powertech as I have seen people tune past this limit.

Now Hyundai DYMOS has 8 speed wet clutch DCT in their back pocket. No one know the spec for sure yet, but it should be 450nm ready from RN30 concept spec.

So let's see who gets the 8 speed DCT next. Likely the i30N DCT version.
constant_weight
post Jan 11 2018, 09:34 PM

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QUOTE(wkc5657 @ Jan 11 2018, 05:07 PM)
This is interesting....

Best quote : "At Kia and Hyundai I spend more time actually driving and discussing dynamics with engineers than I did with BMW M – there, it was all meetings and arguing about money with accountants."

Speaks volume of corporate focus.
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Check this out. This guy run a car rental company and offer coaching at Nordschleife.

He said Hyundai lied about the i30N 10K laps Nurburging, Hyundai did 50K laps instead. Because he keep seeing the Hyundai. LMAO... jump to 5min.


This post has been edited by constant_weight: Jan 11 2018, 09:34 PM
constant_weight
post Jan 23 2018, 07:55 PM

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QUOTE(Quang1819 @ Jan 23 2018, 07:25 PM)
Impossible lah haha

The last gen second-hand K5 also selling on par with last gen Camry
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My prediction - Camry should still holds some value. In the next 5 years uncharacteristic car like current Altis will have worst rv.

The reason is market transition. Now the 80's are on average mid 30. 90's are in mid 20. Wait until 90's+ in the 30 and become main consumers we have very different market.

The 90's are different monsters that will enjoy life more. They looking for different values. The IoT (internet of things) 5G hyperconnected cars are designed for them. I think the luxury brand rv will holds better in next 5-10 years. We should see the brands form alliance with common standards and protocol. When you buy car, you probably consider if your home smart appliances are compatible first. You likely get same brand of appliances throughout the house to avoid headache. You ended up rely on certain brands, ultimate level of brand loyalty strategy.

2019 is the year we should see the IoT cars starting from luxury brands. I think Hyundai Motor Group is prepared for this market transition especially Kia brand oriented for young buyers. Hyundai likely start offering the tech with Genesis first.



This post has been edited by constant_weight: Jan 23 2018, 08:00 PM
constant_weight
post Jan 23 2018, 09:08 PM

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QUOTE(KennyKB @ Jan 23 2018, 08:15 PM)
RV usually depends on reliability, maintenance cost, spare parts availability and fuel economy. Those who buy second hand cars typically have to be mindful of the above. Brand perception helps but a car which satisfies all the above criteria will have good RV irrespective of brand.

Technology may help to sell a brand new car but it won't help to get good RV if it doesn't satisfy those 4 criteria. What is uppermost in the mind of the used car buyer is not the toys but the maintenance cost.

I expect the gap in RV between Korean and Jap cars to narrow as K-cars get better and better. As for Continental cars they will always have low RV because they cost a bomb to maintain after their warranty run out. No technological toys is going to help.
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You are right provided the tech dies and market transition did not happens. I truly believe it will take off, and we judge again in 5 years. If you take a look at the previous techs like air cond, infotainment unit, bluetooth, usb, they were all special selling point at one point of time, but all become basic necessity today. Just like your smartphone, mobile internet, can you imagine living without them?

Now car without android auto, apple carplay, or mirror link is automatically skipped for young buyers.

https://www.gartner.com/smarterwithgartner/...hnologies-2017/
We are in the market transition, IoT and self driving car are at the peak of Gartner chart. We should see their successfulness in 2-5 years. The key differentiator this round vs the older time like aircond or bluetooth in the infotainment were new is the Platform. Bluetooth or aircond doesn't have a platform to bind you, but the services enabled by IoT do. Rumors said Apple secretly building car, no Apple don't want to build car to compete with all the established players. Apple want to build the platform for the car makers to hop on. We have Google, Cisco, Microsoft, Nvidia, etc all the giants that traditionally not related to car aiming at this big pie.

Another market transition is the moving to service based revenue. Why? Because the shareholders love to see stable recurring revenue. The future cars likely being sold at small margin but comes with subscription package to enjoy full features. You get the tech subscription + the traditional maintenance as a package. You pay monthly cost, and you get to replace any faulty parts, and OTA updates. So the bawah pokok mechanics are at their dawn, except the new generation that capable of handle the on board computers, and professional tuners for the enthusiast performance car maintenance. It also means the traditional used car market also screwed as the car makers can take the car back and sell them with cheaper package. Maintenance will be monthly fee and worry free.

So ultimately, they are no longer toys. They will be real basic needs for future generations. You and me can reject them just like my grandparents dismay looking at our smartphone. This day will come eventually even if Malaysia is 5 years behind the world.

I won't say Continental car rv will be matching the average consumer brands, but it will be much better than now. Because the TCO (total cost of ownership) is more predictable via the subscription. Even though the subscription will be be doubt more premium, but it is predictable which encourage more buyers that even can afford the cost today, but turn away from continental car because of fear. The 90's will certainly be attracted

This post has been edited by constant_weight: Jan 23 2018, 09:18 PM
constant_weight
post Jan 25 2018, 11:54 PM

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Stinger and Genesis G70
constant_weight
post Jan 30 2018, 04:52 PM

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QUOTE(wkc5657 @ Jan 30 2018, 04:43 PM)
I'm no marketing professional but I'll give a breakdown from my observations

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My take, only one point. A lot of people never own/drive/sit in a good car for their entire life. They also not engineers.

So without experience and without knowledge, they buy base on what they can see/touch in show room when they become rich enough to buy good car. Test drive doesn't help as they can't appreciate the handling, stability, confidence in the test drive.

 

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