Calculated load

[Speed3kid93]

Hey guys.

Quick question. I have some data logs from late fall and my calculated load peaked at 2.65 and stayed around 2.5 for a little while after that before eventually falling.

Now In the summer heat my calculated load maxes at 2.4 and however around 2.25-2.3.

My question is how much should the load number decrease going from cool fall weather to hot summer weather.

Is it normal for the number to go from 2.65 to 2.3-2.4?

Or does this mean my car is losing power/torque?

I thought that load based tunes will change boost and timing to always hit your load target no matter how hot or cold it is? The whole point of load based tunes is to avoid boost spikes and have consistently torque year round.

Someone please explain because I’m freaking out and afraid my car has lost power and will continue to do so

[Vansquish]

Your car has lost power and will continue to have lost power until the weather gets cooler.

A load-based tune will help you have more consistent performance across seasons. However, hotter ambient air means hotter boost air temperatures as well. The hotter the air entering the engine, the less dense the air is, and the lower the O2-carrying capacity of the air as well. Accordingly, the hotter the air, the less power you will make.

Additionally, the turbo has limits. At some point it just becomes a really hot hair-dryer and cannot actually provide the boost necessary to make the power you would make in colder weather without running far beyond spec. Finally, the hotter the air entering the combustion chamber, the less boost you can run without causing massive knock issues as well.

[Speed3kid93]

How much power do you think I have lost.

My maf g/s went from 310 to 280 and load from 2.67 to 2.3-2.4

[Vansquish]

Why does it matter?

[Jeff23spl]

Originally Posted by Speed3kid93 How much power do you think I have lost. My maf g/s went from 310 to 280 and load from 2.67 to 2.3-2.4

It doesn't matter much but as a rule of thumbs i used to compare my own g/s to be close to my old fwd mustang dyno whp....
....310 with a k04 let me think you may either have a very effective setup or your maf cal is just a bit more optimistic than what i'm used to see.

[Speed3kid93]

The main thing is I want to make sure that im losing the correct amount of power. I want to make sure I’m not losing power due to engine problems.

For example if heat typically makes people lose 10-20 horsepower and I find out that I have lost 40 horsepower then I know I should be looking into other issues that are also causing the motor to lose torque.

[Vansquish]

Originally Posted by Speed3kid93 The main thing is I want to make sure that im losing the correct amount of power. I want to make sure I’m not losing power due to engine problems. For example if heat typically makes people lose 10-20 horsepower and I find out that I have lost 40 horsepower then I know I should be looking into other issues that are also causing the motor to lose torque.

"Heat" is pretty fucking vague, and there is no "correct amount of power" to lose. Use your brain a bit, and you'll realize this.

There are a shitload of different variables that determine your engine's output. If you want to know if your engine is healthy, then you need to perform proper maintenance and check actual measurements of engine health like compression, leak down, fuel economy and trims, and the like. You can't just make a determination of engine health on the basis of some forum posts. Your engine has been through an entirely unique history with unique operating conditions. You can't expect it to match the results of some other motor in a different car with a completely different history.

[Speed3kid93]

Ok that makes total sense.

I have had a compression test done but my vacuum reading at idle is on the high end f what’s acceptable which tells me the compression is still good.

I read a study that said you can tell how much compression you have by the vacuum reading.

I know each car should get a slightly different reading but it gave a range of what it should be around

17-22 in/hg means you have good-perfect compression. The close to 22 the better

Anywhere under that means you are losing or have lost compression.

My reading is currently 10.5 psi which is equal to about 21 in/hg.

Either way I still want to get a legit compression test done.

Other than this the motor seems very healthy. Not leaking any oil and it still making good power.

[Jeff23spl]

what you found is fine for an asthmatic engine and was used a long time ago...

despite the usual 1-2% gage error accuracy (some can even be 5%)
The boost/vac gage (or sensor) is referenced against atmospheric pressure like in a n/a intake. (There is just 1 port connected.)
In a turbocharged engine: the engine vac is referenced to the turbo discharge pipe and if turbo spin just enough to rise the charge pipe by 1-2 inch or mercury above barometric, you would need to add this pressure to the reading you got on the gage unless you are using a differential pressure gage with one side on the intake and the other in the charge pipe...

The best remain a compression and a leak down test if you really want to know.

[Vansquish]

Originally Posted by Speed3kid93 Ok that makes total sense. I have had a compression test done but my vacuum reading at idle is on the high end f what’s acceptable which tells me the compression is still good. I read a study that said you can tell how much compression you have by the vacuum reading. I know each car should get a slightly different reading but it gave a range of what it should be around 17-22 in/hg means you have good-perfect compression. The close to 22 the better Anywhere under that means you are losing or have lost compression. My reading is currently 10.5 psi which is equal to about 21 in/hg. Either way I still want to get a legit compression test done. Other than this the motor seems very healthy. Not leaking any oil and it still making good power.

Originally Posted by Jeff23spl what you found is fine for an asthmatic engine and was used a long time ago... despite the usual 1-2% gage error accuracy (some can even be 5%) The boost/vac gage (or sensor) is referenced against atmospheric pressure like in a n/a intake. (There is just 1 port connected.) In a turbocharged engine: the engine vac is referenced to the turbo discharge pipe and if turbo spin just enough to rise the charge pipe by 1-2 inch or mercury above barometric, you would need to add this pressure to the reading you got on the gage unless you are using a differential pressure gage with one side on the intake and the other in the charge pipe... The best remain a compression and a leak down test if you really want to know.

It is true that the best choice is to do a compression and leak down test to check the health of the engine.

However, @Jeff23spl;, I think you are reading too much into the 10.5psi (~21inHg) number. I think there is some confusion over which scale @Speed3kid93; is using for his data. -10 to -11psi is reasonably good for vacuum at idle on a healthy L3VDT motor.

[Speed3kid93]

When you say reasonably good what do you mean exactly?

What would a good/great vacuum reading be on our motor?

And what would a bad reading on our motor be?

[Vansquish]

Originally Posted by Speed3kid93 When you say reasonably good what do you mean exactly? What would a good/great vacuum reading be on our motor? And what would a bad reading on our motor be?

You can look up that information just as easily as I can.

[Speed3kid93]

I looked it up and seemed to get a lot of mixed answers. Everyone seems to say -21-22 in/hg is perfect for our motor.

When you do the math -10.5 psi equals -21.5 in/hg

But then you said that -10.5 is only decent so now I don’t know

[Jeff23spl]

Originally Posted by Vansquish However, @Jeff23spl;, I think you are reading too much into the 10.5psi (~21inHg) number. I think there is some confusion over which scale @Speed3kid93; is using for his data. -10 to -11psi is reasonably good for vacuum at idle on a healthy L3VDT motor.

i know, the relative pressure reading would be printed with a negative sign, for vacuum....

And i think we both agree for the rest, reading vacuum with a low accuracy gage (or probe) won't give accuracy results to know about how much the rings could leak but it would be enough to tell if a valve is melt or a piston is broken....

Op was worried about missing 1 inch of mercury and my point was to explain there is more reading error in the way he read it, than the 1 inch of mercury he think he miss....

[BuddySpeed3]

Originally Posted by Speed3kid93 My question is how much should the load number decrease going from cool fall weather to hot summer weather. Is it normal for the number to go from 2.65 to 2.3-2.4? Or does this mean my car is losing power/torque? Someone please explain because I’m freaking out and afraid my car has lost power and will continue to do so

The calculated load will decrease a lot in warmer weather, and you will definitely make less power. It's crazy just how much MORE air flows through the engine in the fall compared to the summer. The more power the engine makes, the closer it gets to the knock threshold. This is why I decided to start HYBRID tuning my boost and fuel curves in the fall season, which gives me an idea as to where the limits of the fuel system and octane are. It also gives you an idea as to whether or not the car will suffer from boost creep.

When summer comes around, there aren't any surprises, just less power. From there tweaks to the map can be made to regain some of that lost fall season power, whether it be through timing or boost

As others have said, load tuning can also somewhat remedy the inconsistencies in power output between seasons, but this would still mean that tuning in the coldest weather the car will see is a good idea to see what peak loads will be achieved. In most cases, the turbocharger needs to work really hard to even come close to achieving those higher loads in the summer. There's just not enough air density in the summer compared to the winter.

[Jeff23spl]

right, this is why checking your pump pressure during summer is almost useless, even if it is ok, you may run out of fuel at winter.

[Speed3kid93]

I did look it up but I have gotten a little f mixed answers. From what I read 10.5 psi I said perfect and that is where a perfectly healthy motor will be at.

But then you said 10.5 psi is only decent so I’m not sure who is correct. That’s why looking up info on the internet is not always a sure thing because a lot of people think they know what they are taking about but don’t.

But @vanquish I have seen your name on many posts and you seem to be a very well respected and knowledgeable member so I am coming to you for the answer

Reasonably good/decent is a very broad term in my opinion and I’m wondering how much money and time I should spend looking into my motor

@vansquish

Sorry typo

[Vansquish]

When I said, "reasonably good," it was a turn of phrase, nothing more.

[Speed3kid93]

Ok so I’m going to assume that you are trying to say I shouldn’t worry and the numbers I’m seeing are good.

I hate assuming but Im this case I’m pretty confident you are trying to tell me to stop worrying

[Vansquish]

Originally Posted by Speed3kid93 Ok so I’m going to assume that you are trying to say I shouldn’t worry and the numbers I’m seeing are good. I hate assuming but Im this case I’m pretty confident you are trying to tell me to stop worrying

Correct.

[MSMS3]

Originally Posted by Speed3kid93 I looked it up and seemed to get a lot of mixed answers. Everyone seems to say -21-22 in/hg is perfect for our motor. When you do the math -10.5 psi equals -21.5 in/hg But then you said that -10.5 is only decent so now I don’t know

You are over analyzing this “power loss” issue and placing too much value in both idle vacuum and in calculated load.

As has been said, both your calculated load value and your g/s mass air flow will vary widely based on changes in ambient temperature and heat soaked BATs. Heat really affects the power of forced induction engines (both turbos and supercharged). So does barometric pressure/altitude. Your intercooler efficiency, it’s size, location, and your driving speed to push air through itnplay a big role in bringing BATs back down. Even the ratio of coolant to water in your radiator, which affects general engine cooling in hot summer weather, also plays a role.

There is no magic formula to calculate the effect, but power loss in the summer is noticeable to everybody. It is significant, especially after long pulls or multiple WOT with little time for recovery really sap power.

Your tune is doing what it can to adjust, but just realize that hot air expands its volume and there are fewer oxygen molecules than in cool or cold air. The turbo has to work harder to try to compensate, but the harder it works, the more internal heat it produces.

These cars make more power in cool dense air for all these reasons. Trying to match your cool air g/s flow in the summertime is fantasy.

If your compression is fine, your leak down percentages good, you have no boost leaks and your logs show you are reaching boost and AFR targets, and you are not pulling timing, then you are performing well. But, power will be down in the summer.

Stop obsessing and live with it.

[Speed3kid93]

Thank you to everyone who responded and helped. I have bad anxiety and worrying is one of my strong points.

I appreciate you taking the time to post and respond.

Also how much does E85 help the power loss in the summer?

I am also thinking about getting meth injection to help combat the bats in the summer.

The problem with meth is it seems to be very expensive and not very easy to get. The only place you seem to be able to get it Ian online from a place like vp racing.

I have seen some posts saying you can get some type of meth from Home Depot but I have no idea if that even works or is safe

[BuddySpeed3]

Originally Posted by Speed3kid93 Also how much does E85 help the power loss in the summer? I am also thinking about getting meth injection to help combat the bats in the summer. The problem with meth is it seems to be very expensive and not very easy to get. The only place you seem to be able to get it Ian online from a place like vp racing. I have seen some posts saying you can get some type of meth from Home Depot but I have no idea if that even works or is safe

E85, In tank Meth, and Meth Injection all provide higher octane, which allows more timing to be ran without the engine knocking. This can somewhat negate the power loss in the hot summer, but tbh nothing makes power like cold dense air.

Many people including myself run In Tank Methanol with great results. It's pretty much Ethanols poisonous cybling

[Fstrnyou]

If you have high anxiety, why do you want to add devices that give regular people some anxiety?

[Speed3kid93]

I was talking more about meth injection because it’s supposed to lower the air intake temps below ambient in some cases. That must make a decent difference. I already have an e50 tune but it still feels like I’m losing large amounts of power

[MSMS3]

Please stop obsessing. Below ambient doesn’t mean much when ambient is 90+ degrees in the summer versus 40 degrees or lower in winter. That’s a huge delta that meth injection is not going to erase.

If you want meth injection, go for it, it will help, but it is not going to magically turn summer into winter.

And yes, you will lose power in the summer. You cannot make hot summer air as dense as cold winter air. Physics is physics.

[Vansquish]

Originally Posted by Speed3kid93 I was talking more about meth injection because it’s supposed to lower the air intake temps below ambient in some cases. That must make a decent difference. I already have an e50 tune but it still feels like I’m losing large amounts of power

Meth injection can also hydro-lock your motor. I wouldn't recommend doing it if you've already got anxiety issues.

[Fstrnyou]

It can also not come on when you expect it to...then oops.

[whatsabrooklyn]

if you are worried about getting more power, i guess just upgrade the k04 to something larger. it should be more efficient than pushing the k04 really hard. a bigger turbo should easily increase air flow. = more hp... if your already at the limit of the k04, then that seems to be the next step. you already have some of the bolt-ons.

are you worried that your engine is struggling or you just want more power (like in the winter compared to sumer)?

[Fstrnyou]

FWIW, my BATs at the end of a 4th gear pull were above 170f...on a cool day. Kept sending it and never considered using meth injection as the solution. I did have a few gallons of E85 in the tank though.

I even did a 3rd through 6th gear pull just to see. With temps that high, I have the tune set to de-rate the power so much that it's fairly useless to keep pushing it. It pretty much runs wastegate pressure at that point.

[Jeff23spl]

i like w/m but i have to agree with the above comments, the more gadget you add the more risks of problems you get. I live perfectly with it but if you are anxious don't do that!

Dont expect too much with it anyway, it increase octane and reduce bat but i never personally seen it below ambiant or coming close... (over 8 years of use.)

If you still consider it or just to poor it in your tank, you can find methanol at any hardware store as a paint cleaner, it is also what is used to dry the water out of fuel tank or truck compressor air line during winter etc...

There is also better w/m kit than others, some basic kits is like modding a car by just adding a mbc to rise boost....And then, arguing a turbo car is not reliable....
It helps to do it carefully but you still have more parts prone to fail.

as said, upgrading the turbo is the best thing to do at this point. you could get 1 for the flow you want during summer and just restrain it for colder temp with load control. A larger turbo that remain in it's efficiency area will work at lower bat and lower boost for the same power flow.