Engineers Clean Drive Tuning is useless, and needs a fix. (Math inside!)

GoStu

GoStu
TL: DR Version:
Higher power draw on Clean Drive Tuning not only generates more heat passively, it also restricts Powerplants from going deeper on Low-Emissions mods, or forces higher grades of Overcharged Powerplant to be used. Not only does Clean Drive Tuning underperform compared to Dirty, it's going to make your ship warmer. Edit(s): The ONLY exceptions are in purely silent running builds, where it can eke out a slim thermal performance bonus - at a really bad cost in power draw and sub-par performance, or for explorers challenging themselves to land on the hottest planets out there.

LONG VERSION FOR MY FELLOW MATH NERDS:

I've been doing some engineering for a stealth Diamondback Scout build & decided to look into all options to keep my ship colder. Efficient weapons, lower Thermal Load rolls on weapons without Efficient, Low-Emissions Powerplant. When I got to Thrusters, I decided to look at Clean Drive tuning instead of Dirty, and realized Clean is likely to be worse than Dirty even for silent builds.

First of all, some background on heat mechanics here: https://forums.frontier.co.uk/showthread.php/286628-Research-Detailed-Heat-Mechanics

The important takeaway from that is that passive Heat generation of a module correlates with its Power Draw.

Now let's compare two Diamondback Scouts using 4A thrusters. 4A thrusters draw 4.92 MJ of power before engineering, which I'll round up to 5 MJ to keep the math cleaner. They have a Thermal Load of 1.3, which is extra heat applied when Boosting. Their stock Optimal Multiplier is 1.00 - this being the main statistic which determines Thruster performance unless you are very close to Optimal Mass. These Scouts will both have A-rated Power Plants that have a Heat Efficiency of 0.40, meaning that the Thrusters with their 5MJ draw are constantly generating 2 Heat/second that must be removed from the ship.

Now, take these two ships to Professor Palin. The first will get Grade 5 Dirty Drives while the second gets Grade 5 Clean Drives. I'm going to ignore the potential for Secondary Effects on the roll as those are being discussed to death in other threads right now - for the sake of comparison we'll assume they cancel out across ships. We'll also assume that they get the best possible versions of each primary roll for the sake of discussion.

The Dirty ship gets the following multipliers applied:
+8% Integrity
- 5% Optimal Mass
+30% Optimal Multiplier
+8% Power Draw
+40% Thermal Load

The Clean ship gets the following multipliers:
- 16% Integrity
- 5% Optimal Mass
+18% Optimal Mass
+16% Power Draw
-60% Thermal Load

Let's get the obvious out of the way first: the ship with Dirty Drives will significantly out-perform the Clean Drives ships for speed and agility. Also, should the drives take damage from enemy fire (a risk for any Silent Running build), the Dirty Drives ship is actually stronger than an unmodified ship and is far stronger than the Clean Drives ship. Integrity of a key module like Thrusters or Powerplant can easily be the difference between winning or at least escaping, or ending up dead.

In terms of thermal performance:
The Dirty Drives now draw 5.4 MW of power, generating a constant 2.16 Heat/second. While boosting, add 1.3 Heat/Second in boost * 1.4 = 1.82 Heat/second
The Clean Drives now draw 5.8 MW of power, generating a constant 2.32 Heat/second. While boosting, add 1.3 Heat/Second in boost * 0.4 = 0.52 Heat/second

So the difference in boost between Clean & Dirty is and extra 1.3/s, subtracting the base 0.16 passive heat generated for total difference of 1.14 Heat/Second difference. So far, the Dirty Drives run a bit colder until you Boost, and after the boost the Dirty Drives ship will cool down faster due to reduced heat addition.

Now let's compare against that Power Plant. The Diamondback Scout's 4A Powerplant generates 15.6 MW of power. This is more than enough for a shieldless silent scout, so the owners of the ships can take the builds to get Low-Emissions Powerplants added. Using two sample builds:

Dirty: https://eddp.co/u/QxPQDqS1
Clean: https://eddp.co/u/jfdMj8Nw

We can see that the Dirty ship can manage to go one grade deeper on the Low-Emissions powerplant than the other, which changes the multiplier on Heat/Power from 0.28 to 0.24 for EVERY module on the ship.

Dirty draws 12.88 MW of Power @ 0.24 Efficiency = constant 3.09 Heat/Sec added to ship
Clean draws 13.27 MW of Power @ 0.28 Efficiency = constant 3.71 Heat/Sec added to ship

The extra 0.62 Heat/sec offsets the majority of the extra boost heat on the Dirty Drives ship; meaning the Dirty Drives ship is actually gaining only 0.42 extra Heat/Second in a Boost and is 0.62 Heat/sec colder when not boosting.

*Caveat: Dirty Drives ships is very slightly over its maximum power, and the builds shown are extremes. However, I feel the math still applies overall given that players cannot always count upon getting best/extreme outcomes on engineered modules.

Also, feel free to observe the massive speed difference between the two builds. There's a 50 m/s difference in boost speed, 36 m/s difference in non-boost speed, and the dirty drive ship turns quicker as well.


Proposed Fix:
I'd suggest that the Optimal Multiplier on Clean Drives be increased somewhat and the Power Draw be decreased to be in line with Dirty, if not lower. As it stands right now, Clean Drives is a complete non-choice compared to Dirty Drives. For insult to injury, feel free to compare a good Grade 3 Dirty Drive mod as well. Spoiler: it's better than Clean 5 and comes from a far engineer to unlock and requires way less exotic and in demand material.

(I've omitted Drive Strengthening from the discussion as it does something completely different, even if I'm unaware of anyone actually using Drive Strengthening due to performance penalties).



FIRST EDIT:

From another post on this topic, here's some experimental results: https://forums.frontier.co.uk/showt...is-Pointless?p=5562124&viewfull=1#post5562124
These show that Dirty Drives actually stay silent slightly longer than Clean (due to their lower Power Draw) and both are worse off than Stock drives as stock drives have the lowest power draw. This is when the

It appears that Thermal Load is applied during drive use, when speeding up or slowing down. (Something my straight-line tests missed, I only tested at constant 100% throttle and 0% throttle). I've amended the conclusion above - Clean has a very, very niche role and isn't really a huge advantage there. It's especially bad when one considers the far weaker performance - 50 m/s difference between Clean and Dirty 5 is criminal.

Second Edit:

There is some niche applicability for Clean Drives if you're an extreme explorer interested in roving very high G 'crusher' worlds or tire-meltingly-hot worlds next to stars, where any extra heat can be the difference between toasty death and toasty life. Nonetheless, the usefulness of this blueprint is very slim at best and it is deserving of some rebalancing such as reduction in Power Draw.
 
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Devari

D
Clean drives are very useful for stealth builds as the heat you generate when boosting is dramatically higher than what you see during normal operation. What you don't seem to recognize with your numbers is that the difference in boost heat for the mods is still quite dramatic even with a better low emissions plant mod and when you are operating near the edge of overheating the dirty drive boost will push your heat higher than what your ship can handle. I don't know if you've actually flown stealth builds with clean drives but it makes a massive difference. I have three stealth builds (Diamondback Scout, Asp Scout and FDL) and each of them can actually boost a few times with clean drives during silent running before overheating without needing to use a heat sink. Try that with dirty drive tuning and you'll see a massive difference because your ship can't actively dissipate that extra heat when in silent running.
 
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goemon

goemon
Devari said:
Clean drives are very useful for stealth builds as the heat you generate when boosting is dramatically higher than what you see during normal operation.
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this. plus thruster usage above higher G surface.

i suggest you take your dirty drive ship to achenar 3 (high G) and to skardee 1 (most heat), best testing systems for those things in the bubble. compare to the same ship with clean drives, and check back - i have tried to do the math like you, but it does not take those conditions into account, would be interesting to see some test on it! i can tell you that my DBE (!) with dirty drives overheats flying above skardee 1, while it doesn't with clean drives. i can also tell you that my surface explorer eagle with clean drives can fly upside down at 3G, while it melts doing those stunts with dirty drives.

as long as you don't move your heat will be lower with dirty drives down to higher power usage of clean drives, you are right. as soon as you use thrusters, either massively by boosting, lateral and vertical thrusters, yaws, flying upside down etc. etc., manouver above high G surfaces, or in a hot surrounding, the heat will be a problem.
 

Devari

D
Gunnet said:
At last, vindication for my G3 low emissions + G5 dirty drives (+104% heat!) exploration ship :D
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Well if you're exploring then you're spending almost all of your time in supercruise and you can't boost in SC so you can probably get lower heat levels for fuel scooping with your build.
 
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Gunnet

G
Devari said:
Well if you're exploring then you're spending almost all of your time in supercruise and you can't boost in SC so you can probably get lower heat levels for fuel scooping with your build.
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Indeed. I took the +104% thermal load roll because the other stats were pretty decent, thinking that I would probably end up storing that one and rolling a fresh drive for the explorer. But scooping turned out to be a breeze with the low emissions PP, and having a 533m/s boost is nice piece of mind for returning to the bubble.

Like you mentioned, clean drives are still great for stealth ships though. My stealth DBX is something of a range queen rather than a real fighting ship, but flying around with ice on the canopy is always fun.
 

Devari

D
Gunnet said:
Indeed. I took the +104% thermal load roll because the other stats were pretty decent, thinking that I would probably end up storing that one and rolling a fresh drive for the explorer. But scooping turned out to be a breeze with the low emissions PP, and having a 533m/s boost is nice piece of mind for returning to the bubble.

Like you mentioned, clean drives are still great for stealth ships though. My stealth DBX is something of a range queen rather than a real fighting ship, but flying around with ice on the canopy is always fun.
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I've found with my stealth FDL (which I rarely actually enter stealth mode with) also benefits from clean drives as the FDL has rather poor heat management and I run a "hot" build with overcharged incendiary multis on the medium hardpoints. At first I would overheat within a few seconds when firing my incendiary multis and it wasn't very practical for sustained combat. After fitting a combination of reduced thermal load secondaries on the multis (which I gradually collected from rolls on other ships), clean drives and a -25% heat mod on the power plant I basically never overheat in combat now and can still reach a boost of 465. When I used dirty drive tuning (which got me a boost of 470) I would overheat quickly when boosting and firing full weapons. Considering how much I boost in my FDL during combat I've found the clean drives are quite useful even though I rarely actually use it as a stealth build. The FDL is a bit unusual here since it has a very large power plant for its size which provides a massive excess of power so you can easily fit BOTH clean drives and a good low emissions PP mod without difficulty. In general though any combat ship with lots of excess power and poor heat management could probably benefit from clean drives to some extent if they plan on boosting frequently during combat.
 

domaq

domaq
Thank you for the analysis but there is a flaw in your theorizing. The Dirty and Clean rolls that are part of your assumptions are god rolls. I've done a couple hundred G5 Dirty rolls and never seen a +30 mult coupled with +8 power and only +40% thermal. Most people's typical rolls will be the min/max RNG that we all know and love. When you make that your assumption (a far more likely scenario IMO), you will see on paper what others in this post see in practice.
.
A G5 Dirty roll with +30 mult, +20% power, and +100% thermal compared to a G5 Clean roll of +18 mult, +25% power, and -60% thermal would give numbers of:
Dirty Drives draw 6.0 MW of power, generating a constant 2.4 Heat/second + 2.6 Heat/second boosting (1.3 * 2.0) = 5.0 total heat/sec while boosting
Clean Drives draw 6.25 MW of power, generating a constant 2.5 Heat/second + 0.52 Heat/second boosting = 3.02 heat/sec while boosting
.
That is a big disparity. So while your resting temp will be lower with Dirty drives (as you state), the heat generated from constant boosting in an FDL or hovering on a high G planet (where thrusters are at max), will be noticeable.
.
The extra power required from a normal G5 Dirty roll may also invalidate the argument regarding the PP however I have not testing the build to know.
.
All that being said, I will still usually run with G5 dirty on my exploration vessels due to the balance of wanting low heat in SC and then offsetting the need for good thrusters on a planet with the extra heat they will create to avoid pancaking into the ground.
 

-Denali-

D
Limoncello Lizard said:
It's not going to be much use for anything. I've got a 7A powerplant with G3 low emissions on my Python. It has slightly less power output than a 6A. Drop that power any more and it won't be any use to me.
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If you fly a ship without shields/boosters/scbs and use kinetic weapons you'll be pretty hard pressed to use all that power.
 

The Tick

The Tick
I'm more than surprised that you assume that the extra thermal load from engineering mods only applies during boosting. That's much different from what I experience during SC, especially while scooping. Did somebody do some research into this?
 

goemon

goemon
TheTick said:
I'm more than surprised that you assume that the extra thermal load from engineering mods only applies during boosting. That's much different from what I experience during SC, especially while scooping. Did somebody do some research into this?
Click to expand...

the thermal load applies during thruster usage generally.

so, FAOFF, no thrusters firing: no extra thermal load

hoovering above high g surface: extra thermal load

using a lot of thrusters or thrusters massively (yawing and pitching at the same time, boosting, do it all above high G surfaces etc.): even more extra thermal load.

during sc: if you are acceleratin/decellerating: extra thermal load.

so, if your are scooping at zero throttle, the effect will be minimal. if you are flying away from the star, therefor accelerating (as can be seen in speed), more extra thermal load in sc. but as you can't use vertical or lateral thrusters in sc, generally the effect isn't very noticeable (a few percent). the physics behind SC are really, really weird :) ... you shouldn't use the thrusters to accelerate at all.
 

domaq

domaq
Goemon,
I just did a couple tests in my explora-conda that do not tally up with your SC comment. 5D Thrusters, G5 Dirty Drives, Power Draw +25%, Thermal -4% (-25% secondary). The stats of the roll aren't really important except to say that I see zero increase in heat while in SC (deep space) between 30km/s and 164c; acceleration/deceleration do not seem to have an impact. The entire time it sits at 15% heat. Maybe this means the ship can vent as much as it gains or it could also mean the thrusters do not create heat in SC besides their basic power usage?
 
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GoStu

GoStu
TheTick said:
I'm more than surprised that you assume that the extra thermal load from engineering mods only applies during boosting. That's much different from what I experience during SC, especially while scooping. Did somebody do some research into this?
Click to expand...

This is based on comparison from throttle-up straightlining temperature vs. dead stop. No heat % changes until boosted.
 

Deleted member 38366

D
If I was to toss Grade 5 Dirties onto my Beluga instead of its Grade 5 Clean Drives, I'd probably need to pop a Heatsink for every Planetary Departure and HyperJump ;)
(likely two or more if I ever dared to utilize Afterburner while FSD is charging)

Clean drives do have their purpose, but it's arguably a rather limited scope of applications.

PS.
I did run Grade 5 Dirty Drives on my Exploration AspX once, transporting them basically for later use in another Ship.
Was a darn fast rig departing Maia, but the heat spiked well beyond 75% in virtually no time. That never once happened running the Grade 5 Clean Drives on that Ship.
 
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GoStu

GoStu
domaq said:
Thank you for the analysis but there is a flaw in your theorizing. The Dirty and Clean rolls that are part of your assumptions are god rolls. I've done a couple hundred G5 Dirty rolls and never seen a +30 mult coupled with +8 power and only +40% thermal. Most people's typical rolls will be the min/max RNG that we all know and love. When you make that your assumption (a far more likely scenario IMO), you will see on paper what others in this post see in practice.
.
A G5 Dirty roll with +30 mult, +20% power, and +100% thermal compared to a G5 Clean roll of +18 mult, +25% power, and -60% thermal would give numbers of:
Dirty Drives draw 6.0 MW of power, generating a constant 2.4 Heat/second + 2.6 Heat/second boosting (1.3 * 2.0) = 5.0 total heat/sec while boosting
Clean Drives draw 6.25 MW of power, generating a constant 2.5 Heat/second + 0.52 Heat/second boosting = 3.02 heat/sec while boosting
.
That is a big disparity. So while your resting temp will be lower with Dirty drives (as you state), the heat generated from constant boosting in an FDL or hovering on a high G planet (where thrusters are at max), will be noticeable.
.
The extra power required from a normal G5 Dirty roll may also invalidate the argument regarding the PP however I have not testing the build to know.
.
All that being said, I will still usually run with G5 dirty on my exploration vessels due to the balance of wanting low heat in SC and then offsetting the need for good thrusters on a planet with the extra heat they will create to avoid pancaking into the ground.
Click to expand...

I chose to use the numbers for so-called "God" rolls as these are the kinds of rolls most players are hoping to achieve, representing a sort of end-state for engineering. If a player has worse than these outcomes, they can always re-roll to try and improve. (The amount of rolls required to actually achieve this & the pain of finding the requisite materials are topics covered elsewhere).
 

Bunkerkind Anni

Bunkerkind Anni
domaq said:
Goemon,
I just did a couple tests in my explora-conda that do not tally up with your SC comment. 5D Thrusters, G5 Dirty Drives, Power Draw +25%, Thermal -4% (-25% secondary). The stats of the roll aren't really important except to say that I see zero increase in heat while in SC (deep space) between 30km/s and 164c; acceleration/deceleration do not seem to have an impact. The entire time it sits at 15% heat. Maybe this means the ship can vent as much as it gains or it could also mean the thrusters do not create heat in SC besides their basic power usage?
Click to expand...

thrusters can be shut down in supercruise... manouvering in supercruise is done by the FSD drive.

why the duplicate topic
https://forums.frontier.co.uk/showthread.php/354115-Clean-Drive-Tuning-is-Pointless

this one with actual testing, not only math is still active
 

GoStu

GoStu
FalconFly said:
If I was to toss Grade 5 Dirties onto my Beluga instead of its Grade 5 Clean Drives, I'd probably need to pop a Heatsink for every Planetary Departure and HyperJump ;)
(likely two or more if I ever dared to utilize Afterburner while FSD is charging)

Clean drives do have their purpose, but it's arguably a rather limit scope of applications.
Click to expand...

These problems are more to do with the Beluga (its heat capacity is really, really bad compared to the size of modules/powerplant it fits) than the relative strengths of Clean Drives.
 
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