is Synthetic essential in Turbo engines?

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Originally Posted By: BrocLuno
To those saying that EGT on gas motors are higher than OTR trucks, you just ain't been there... Cars loaf along at cruise most of their life. Trucks, full fuel - full boost for the whole run-up through the tranny (21 speeds...) and full boost every hill. Up the grapevine it'll be boosted for 1/2 hour easy with the first 4 ft of the 4" exhaust system cherry red (including the turbo) - that's HEAT !!

The comment about farm motors, yeah, 8 hours of plowing with full boost - same as above.

Marine engines working on a push boat - full boost for days up the mighty Miss ...

Well, you do know that the EGT gauges on these three types of applications is merely bling, right?
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As I mentioned, on the farm, it would be full boost for close to eight hours solid. The only times when the boost wasn't peaked was at refueling and lunch.

When I ran the Audi at full boost for half an hour, the sump temperature did not exceed 95 C. Obviously, there would be much hotter spots in the engine, but that does say something about how efficient its oil cooling system was, that it didn't run away.
 
Got a pyro in the shed to go on the Nissan...fat lot of good that it's doing there, but I haven't fitted it yet.

Regarding theoretical EGT's, diesel's HAVE to have lower temperatures than gassers.

Maximum combustion temperature, and therefore exhaust temperature occur at stoichiometric (well a little bit off, but to all intents and purposes at stoichiometric).

The smoke limit of diesels is still way lean of stoichiometric, and they get hotter by adding fuel. Lean mixture causing heating in gassers is because max power is rich, and leaning it off raises temps.

With gassers running around stoichiometric, the actual temps are always going to be higher than a diesel...lean burn gassers will be similar to the diesel case.

The glowing manifolds are an artifact of heat flow. At low loads the mass of exhaust gasses is small compared to the mass of the manifolds and the ability for the environment to suck the heat away.

At high loads, the mass flow is much greater, there is more heat (not temperature) available to get the metal hot, and things that are external to the exhaust gasses themselves get to a higher temperature to shed that heat.
 
As to turbos and synthetics, my neighbour in Canberra when I was a teenager had an aftermarket turbo on a Volvo...was wicked, at 18psi, seeing the faces of the boy racers in their FWD ZZR stickered cars as the trailer with wrecked car in tow was amazing.

The guy who did the engine told Terry that GTX was fine...it would have been, but he refused to idle down, and wasted two turbo centres in a very short period of time.

Agip Synt 2000 10W50 stopped the damage completely with the same driving "style".

The GTX could well have worked if he'd just take the time to leave it idling while he unbuckled the kids and took the pram out of the trunk.
 
Certainly, but your EGTs puttering around on a turbo car on the highway at 90 km/h aren't going to be elevated at all in comparison to driving with a bunch of boost applied for a decent duration. There won't even be any boost at that steady state speed. And, of course, that will be even more apparent if driving something like a Powerstroke on the highway at 90 km/h, towing nothing, which will, as you indicate, have lower EGTs yet. I'm talking about something under very heavy load, and full boost, for hours at a time.

People here regularly panic about turbocharged gassers, when their turbos occasionally don't even provide any boost during an entire drive, simply because the way they're driven, or they might provide a push when leaving a stop light. Normally, the Audi on the highway, at normal highway speeds and steady state (very easily possibly, and actually probable, on a Saskatchewan highway), would be showing no boost.

The theoretical EGT matter is clear. But we don't need to panic about EGTs (or stress on the oil) on a turbocharged gasoline car that sees a whole five seconds of boost as they driver leaves the light to go on a 90 km/h cruise to Saskatoon.
 
Originally Posted By: Shannow
At high loads, the mass flow is much greater, there is more heat (not temperature) available to get the metal hot, and things that are external to the exhaust gasses themselves get to a higher temperature to shed that heat.

Yes, we need to make this distinction rigorous between heat and temperature. Spill boiling coffee on your lap versus a bathtub of warm water, and one will learn the differences painfully.
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Originally Posted By: BobFout
Originally Posted By: Garak
Lots of OTR diesel engines have turbos and use conventional. So, synthetic is obviously not "essential."


We can't make that blanket statement across all applications. EGTs on diesels, especially medium and heavy duty trucks, are typically far lower than gas engines.


Back,when i used to drive truck some of them had pyrometers with stickers that read down shift at 1,200*f or 1,300*f well beyond any oil flash point.
 
I'm not sure I'd want to run synth in carb setup (turbo or not), since I'm not sure how long the oil could stay in the sump, due to gas buildup from cold starts.

I actually don't know if syth is better for that situation or not.
 
Well, If my Detroit EGT's get above 900F on even the hardest, longest pulls, I am not doing things right and not paying attention. The proper RPM's have a great effect on what EGT's are. If EGT's go above 900F for more than the few seconds, I am lugging the motor and need to drop a gear. And my turbos have blankets on them also! EGT probe is right at the exit of the hot side of the turbo. I have a ported, polished, ceramic coated exhaust manifold and twin stacks with Walker Megaflow mufflers on them.

I was curious about the comment about going thru 21 speeds on a HD truck. I have yet to see one of those. Even the old 4 by 5 two sticks give you 20, and those have been pretty much relegated to the history books. The most gears in a modern HD truck transmission is 18 speeds, and they are the rarest of transmissions in heavy duty trucks. Most are 10 to 13 speeds. With the automated manuals, 12 is becoming the norm.

I use a Schaeffer syn blend. I like to invite both conventional and synthetic to the party. And diesel engine turbos typically run temps considerably lower than gasoline engine turbos. But then most modern gas turbos and modern diesel VG turbos are water cooled, so the strain on any oil is lessened considerably.
 
VR1 conventional is a superior oil to M1 syn 15/50.

This is not your traditional conventional vs. syn battle.

The very idea that VR1 can't take the heat? Stupidity. I've run it in turbo engines that had their turbos glowing cherry red in broad daylight, never used a turbo-timer or cool-down, and upon removing the turbos for upgrade, found the bearings to be clean and intact as a new gun.

My oil temps in my Harley hover around 280F, and VR1 never breaks a sweat over 5000 miles, and never shears out of grade.

Same engine would eat M1 15/50 for breakfast.
 
Originally Posted By: TiredTrucker
Well, If my Detroit EGT's get above 900F on even the hardest, longest pulls, I am not doing things right and not paying attention. The proper RPM's have a great effect on what EGT's are. If EGT's go above 900F for more than the few seconds, I am lugging the motor and need to drop a gear. And my turbos have blankets on them also! EGT probe is right at the exit of the hot side of the turbo. I have a ported, polished, ceramic coated exhaust manifold and twin stacks with Walker Megaflow mufflers on them.

I was curious about the comment about going thru 21 speeds on a HD truck. I have yet to see one of those. Even the old 4 by 5 two sticks give you 20, and those have been pretty much relegated to the history books. The most gears in a modern HD truck transmission is 18 speeds, and they are the rarest of transmissions in heavy duty trucks. Most are 10 to 13 speeds. With the automated manuals, 12 is becoming the norm.

I use a Schaeffer syn blend. I like to invite both conventional and synthetic to the party. And diesel engine turbos typically run temps considerably lower than gasoline engine turbos. But then most modern gas turbos and modern diesel VG turbos are water cooled, so the strain on any oil is lessened considerably.
The Kenworth I drive at work has the Cat C15 550HP engine with the twin turbo setup with the 18 speed tranny. When I am pushing full boost (58psi) I have only ever seen the EGT's go as high as 1200 degrees, and that was on a really hot day in the summer. The boss buys Castrol Hyperion 15w40 semi-syn oil for the trucks.
 
Originally Posted By: Jetronic
The vast majority of turbos in passenger cars are NOT watercooled.


Ford's Ecoboost are. VW's 1.8T engine the turbo is water cooled. The Chevy Cruze 1.4 turbo is water cooled. And the list goes on and on. Look on most any modern gas engine turbo and you will see both oil and coolant lines going to the the turbo(s). This is for a number of reasons, mostly to keep turbo temps moderate and to reduce heat soak problems at engine shutdown.
 
Originally Posted By: xxch4osxx
[/quote] The Kenworth I drive at work has the Cat C15 550HP engine with the twin turbo setup with the 18 speed tranny. When I am pushing full boost (58psi) I have only ever seen the EGT's go as high as 1200 degrees, and that was on a really hot day in the summer. The boss buys Castrol Hyperion 15w40 semi-syn oil for the trucks.


True, they can get that high with stock setups and drivers that do not watch RPM's on pulls, but it is not good. And it shows a poor design of the exhaust setup and also not running the engine under full load at proper RPM's to increase flow thru. Exhaust cools in the manifold and the turbo and the exhaust piping. It creates restriction as it cools. If the flow is not kept optimal and kept from cooling too quickly close to the engine the effect is actually beneficial and hot temps are minimized. That is why I use a ceramic manifold, turbo blanket on the turbo, and heat wrap on the flange pipe after the turbo to maximize exhaust flow. And it shows. Instead of those 1100-1200 EGT temps, I experience 200F less exhaust temps on the hardest pulls. And by using a turbo blanket, the compressor side of the turbo air flow is cooler and intake air is 20-30F cooler coming out of compressor side. And when these things are optimized, fuel economy and power are increased. I average 20-25% better fuel economy than the commercial trucking national average. And that is with putting down 515 HP 1850 Torque. Ever ask yourself why so many folks with Cat ACERT dual turbo setups switch to single turbo and do the similar things I have done to mine? This type of stuff is not restricted to CAT, Detroit, Cummins, or whatever. Stock designs are not optimal in many ways. I have done what I describe to many different brands of diesels with good effect.
 
Originally Posted By: CT8
Back,when i used to drive truck some of them had pyrometers with stickers that read down shift at 1,200*f or 1,300*f well beyond any oil flash point.

It's been a long time, but if I recall correctly, the warning range for the EGTs on the farm turbodiesel tractor was around that range, too, but was running under 1,000 most of the times. As TiredTrucker noted, lugging could be problematic, of course.
 
21 was a lysdexic slip for 12 ... The most I have driven is 20 (5x4) and there are many overlaps in that set-up. But it was/is good for low starts pulling heavy equipment out of a farm field. You can walk faster
laugh.gif


I agree on optimizing EGT and flow. But the boss is not into it. He wants "toy" on his motors so we get pulse turbos and stuff I don't care for.

1200 EGT was the normal limit in the old days. Stay away or below was my moto. If it started to get up there I'd drop a gear (13 speeds) and cruise on
smile.gif


The worst I had was a company truck with both pyro charts and speed charts and they would look at both and second guess why we drove XYZ over Gaviota Pass. It was part of initiation for young drivers... Once away from that outfit I could drive more as I meant to and mind my own rules and ideas...
smile.gif


Nowadays a lot of company rigs seem be lugging too much. I think they are stretching for that last 0.1 MPG... Not sure if it's good on the engines or not ...

I agree with the above on VR-1. If it's a home built hot-rod motor without good baseline data, I'd sure start with VR-1 until I knew more about how it was running ...
 
Originally Posted By: TiredTrucker
Originally Posted By: Jetronic
The vast majority of turbos in passenger cars are NOT watercooled.


Ford's Ecoboost are. VW's 1.8T engine the turbo is water cooled. The Chevy Cruze 1.4 turbo is water cooled. And the list goes on and on. Look on most any modern gas engine turbo and you will see both oil and coolant lines going to the the turbo(s). This is for a number of reasons, mostly to keep turbo temps moderate and to reduce heat soak problems at engine shutdown.


Hyundai/KIA is also Oil/Water cooled.
 
Originally Posted By: wemay
Originally Posted By: TiredTrucker
Originally Posted By: Jetronic
The vast majority of turbos in passenger cars are NOT watercooled.


Ford's Ecoboost are. VW's 1.8T engine the turbo is water cooled. The Chevy Cruze 1.4 turbo is water cooled. And the list goes on and on. Look on most any modern gas engine turbo and you will see both oil and coolant lines going to the the turbo(s). This is for a number of reasons, mostly to keep turbo temps moderate and to reduce heat soak problems at engine shutdown.


Hyundai/KIA is also Oil/Water cooled.


I'll have a look, but their diesels definitely are NOT. And the diesels outnumber the petrol turbos 10.000/1 here
 
Hyundai/KIA 2.0T:
There are 2 water lines that feed into the turbo housing on the underside of the turbo beneath the manifold. Number 14 and 15 are the water inlet and outlet lines.


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