Conventional Oil and Direct Injection? thoughts?

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Feb 26, 2016
So here is my dilemma and question. While i understand that some cars simply need synthetic oil i am not a fan of the stuff. I have nothing against it and have used it in the past. But i am a weirdo (not by the standards of this forum i am sure) who just likes to change oil. I like to be under my car every 5,000 miles to change the oil and check the the mechanicals (suspension, ect). I have a 3 hour commute each day at 80mph. So i have always been comfortable on my last 5 cars doing conventional oil every 5k to 7k. oil is always up to temp and i have never had a problem. but here is my question. I have bought several used cars and trucks with about 100k and drive them to 200k-250k and get another car. This time i am thinking about getting a new 2017 car. my previous newest car was a 2003 and a lot has changed since then. I am looking at a basic compact car (versa, elantra, cruze, mirage) and see that several have either direct injection, turbos, or both. I would like to continue to use conventional oil, and understanding that these engine are harder on oil change it every 3k-5k. While many recommend synthetic is it truly necessary? i have seen some UOA on GM GDI engines using VWB that looked acceptable. But does anyone else use conventional oil in there newer cars? While i understand synthetic is better i just think i would be wasting money changing it out as often as i do. I would think that a conventional oil meeting API spec would provide the same protection for my driving style at 3k-5k as synthetic at the same OCI. Interested to hear opinions and recommendations on this question.
For what it's worth, when I used to work in an lube shop I noticed that the Chevy Traverse models made before the GM Dexos spec came out that ran on regular 5W-30 always had really thick varnish under the oil cap whereas the models that ran Dexos synthetic were always spotless. I know it's just a visual thing, but, I always chalked it up to the synthetic oil working harder to keep those engines cleaner. I think it's because DI engines run much hotter than port or throttle body injection systems do.
Unless the OEM require a spec only synthetic oils have, you can absolutely use a conventional. There is research that suggests exactly what you're proposing... GrpII oils at shorter intervals = less deposits.
The graph above comes from this report. Its a pdf so i cannot share. But if you want to read it. Look for this title...
It is a new car with a warranty. Use recommended oil and keep receipts and a log. If you go with the Cruz (if gasoline), then use Doxos 1, Gen 2 oil only. I would also keep the oci down to 5k, at least to start with. Enjoy your new ride, whatever you choose.
Given your daily use, conventional oil may work fine. Highway miles are easiest on oil. Conventional oil is better than it used to be. If it's SN, it could be close to a blend anyway. Yes GDI is hara on oil. Turbos are hard on oil, put the two together and they are REALLY hard on oil so short OCIs are the norm. Check the condition of oil when changing and go from there. A lab test would show you the way if you care to check that out. My 2¢
Given a long highway commute, I'd be seriously considering a passenger car diesel, where a USDM variant (chev Cruize) or a Euro (VW/AUDI TDi for example) When looking ate modern small capacity (often turbo) engines, they work the oil harder than engines of yester year. Any (I repeat ANY) petrol engine that comes equiped with a turbocharger requires synthetic engine oil, unless you enjoy changing turbochargers. The temperatures inside turbo bearings is extreme and mineral oils are unable to hold up. This is especially important if you have a non-water cooled turbo and to regular 'hot' shutdowns (I consider a hot shutdown to be turning the engine off while the turbo is glowing red hot.) The oil bakes and turns to coke in the turbo bearing. upon restart the grit damages the bearing. over time it flogs out and $$ begin to leave your pocket. One other consideration is modern emissions systems. Especially EGR, and DPF's (on diesels.) Both best removed, but your state authority may not view it that way. And of course the humble crank case ventilation system. DI engines are significantly more susceptible to intake valve deposits than traditional port injection engines. Low SAPS synthetics are specifically formulated to leave less deposits. Remember Mineral oils will have a higher NOACK and subsequently higher overall volatility. combined with higher SAPS will definitely increase deposit formation. This has to do with how the PCV introduces a warm moist (oily) gas mix into the intake post air cleaner, which mixes with the particulate containing EGR. the results of course are intake deposits and with no port injectors keeping the valves clean... Well you can search the internet. Bottom line: If you buy a 2017/2018 car, it will come with a very specific manufacturer oil specification. That oil specification will almost 100% of the time require a synthetic base oil to meet the specification. On a personal note: I like to have the best technology working for me. And when it comes to oils that's the latest generation of synthetics. I even run my 1975 Datsun 180b on Synthetics, because why not wink Jordan
If you're plan is to go with a GM T-GDi then you'd best be served using a dexos1Gen2 oil as recommended by GM. This spec guards against LSPI and premature timing chain wear. But a synthetic oil is not necessary to gain this latest specification from GM. Quite a few synthetic blends like Pennzoil Gold and Quaker State Synthetic Blend fit the bill.
Originally Posted By: Salsashark
I have bought several used cars and trucks with about 100k and drive them to 200k-250k and get another car. This time i am thinking about getting a new 2017 car.... Interested to hear opinions and recommendations on this question.
Opinion: I wouldn't do it. Financially it won't make sense, and new tech is generally a mixed blessing at best. Recommendation: Don't do it. You have a system that has apparently worked for you. Stick with it.
I'm guessing that you (the OP) are mechanically inclined since you buy used cars with 100K and routinely get another 100 to 150K out of them.....if that's the case I would continue doing so as that is the most economical thing to do. A new car is not a 'good investment'.
To take us even further off topic, there will presumably come a time when buying a new petroleum-powered car will start to look risky, because it may not, for environmental or fuel supply reasons, stay viable for its anticipated lifespan. Probably not there yet, but I'm not sure I'd be able to spot when we were.
Do the Elantra with the 2.0 and you'll have multiport injection and no turbo. The 17's are highly regarded for fit, finish, and overall quality, and if you like conventional oil, the engine characteristics of the Hyundai and a good conventional oil might be a sweet combination that will last for many miles.
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With the deals I and many other members typically get on a good synthetic oil, I'd pass on the conventional oil in if I owned a DI engine. Any DI engine.
I got my Fiesta Ecoboost for a long highway commute, and I think it is perfect. It has tall gearing and a fat powerband for easy cruising. Despite the easy miles, being a turbo-DI, I will only use synthetic oil. That is mostly because of the heat in the turbo. If it was just DI, I might be okay with conventional oil. In either case, I would have a plan to regularly clean the intake valves. I plan on using the CRC product.
DI Engine = Group III Synthetic at 5,000 mile OCI's seems to be the sweet spot with respect to low engine deposits .
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