Technical How can a valve cover heat up fuel lines?

[Torgus]

@martymil

The fuel line is connected to the injectors which have a physical connection to the head and sit in the combustion chamber. The fuel rail is connected to the engine block. The LPFP & HPFP, like any pump, increases the temperature of the fuel and has a metal connection to the fuel line. When you run a return style fuel system your fuel will heat up even more. Everything is metal on metal from the pump to the fuel line to engine block to the injector to the head to the combustion chamber. As everything has a metal on metal connection they will thermally conduct VERY well. Much better than through air. Air is actually a good insulator and there is plenty of fresh air in the engine bay when driving.

Metal all the way through from combustion chamber to fuel rail connection. Metal is a great thermal conductor.

Sits right against the head and in the chamber:

You think this is a bad design will heat up the fuel in a way noticeable for real world performance?

Using your logic the valve cover much be significantly hotter than the block the fuel rail is connected to:

The valve cover would have to be orders of magnitude much hotter than the block & head for more thermal heat transfer to happen THROUGH the air than through the metal on metal fuel rail to block connection or any of the other metal on metal connections that lead all of the way from pump to the combustion chamber.



You then have to remember we are talking about roughly 2 inches of fuel lines and how fast the fuel passes through.

Your statement the m18 valve cover has a bad design because of the fuel rails is one of the most insanely idiotic things I have ever heard.

 

[The Convert]

You’re confused. In temps exceeding 100f none of that applies.

 

[martymil]

Metal radiates heat and any steps taken to reduce fuel temps will help.

Taking the HPFP pump of the block and putting it on the belt like when using a shotgun drive will help especially when its
runs in direct airflow path and away from the block.

Phenolic gaskets between the fuel rail and block will reduce temps, just like on aluminium manifolds.

Doing the cowl mod and having airflow around the rail, lines and injectors will help keep the fuel cooler.

The fuel flowing through the injector will not have enough time to heat up but will help cool the injector if it enters
at a lower temp, if you keep the fuel cooler before it enters the injector you will also prolong its life and help it run better.

By reducing fuel temps you also increase its density thus needing less of it, helps with HPFP pressure and helps to lower egt's just like meth.

These cars weren't designed to run it hot temps, but in German weather and at stock power levels.

Each of those steps will help and might not be much but it can be the difference between running normally or misfiring.

 

[martymil]

I'm in the process of designing my own finned fuel rail that is mounted on proper phenolic mounts instead of steel like the factory version
to help reduce temps even further if needed.

 

[Torgus]

Way to go off topic. How does the valve cover heat up the fuel via the fuel lines in any measurable way through the air gap? The VC would have to be hotter than the block for this to happen, which it is not.

The VTT vc was better than m18 vc regarding fuel rail temps which was your original statement. You said the m18 vc makes the fuel lines run hotter. Do you have any proof? Like with a thermal camera or thermal couples? Any thing other than your conjecture? By the way you can't capture what you are talking about in an mhd log so don't even try.

Over spinning a pump will net higher fuel temps not sure why you would even mention the hpfp and temps. The VTT hpfp overspin solution is connected via metal on metal to the engine. It will all heat soak the exact same way as the stock hpfp if not faster because it is overspun constantly.

All of this is connected via metal on metal from the head to the injector to fuel line. Unless you can thermally decouple the injector from the fuel line so the injector does not warm up the fuel line it is a moot point. You have heat coming from both ends of the fuel line system with 2 inches of fuel line running over a VC with an air gap.

A fuel rail with fins...I just can't even...

 

[martymil]

I'm not off topic it all adds up to the final temp and the cover does not help, it might not be a great amount but still adds up.

 

[Torgus]

The topic is: How can a valve cover heat up fuel lines? (In any measurable way that actually matters)

I have explained clearly how the fuel line over the VC, a 2 inch metal line with an air gap from the VC, is heated up from both sides: the injectors and the hpfp. The lpfp also heats up the fuel especially in a return style system. I have also explained that the VC is attached to the head and block like the injectors in the head hpfp on the block attached to the engine via the hpfp metal when overspun or in OEM configuration etc.

How does a VC heat up the fuel line in any signifigant way?

 

[martymil]

Now we are not talking about an oem configuration are we, you no longer run a stock valve cover.

Get an IR thermometer and measure it, its like running with an insulated stock engine cover a lot less airflow.

When you have airflow running under and over the lines you get some cooling effect and when the lines are countersunk into the valve cover
you get much less, try it with just a room fan on a hot day.

Having phenolic washers between the fuel rail helps heaps too and having the proper ceramic coating on the valve cover to keep heat in and
away from the rail and lines.

So what I'm trying to say every bit helps and that goes for exposed rail to injector lines and countersinking them into the valve cover is
counterproductive, if you lived in a climate like ours you might understand the things we have to go through to keep our cars running properly.

 

[The Convert]

You are truly a pig in shit if I’ve ever seen one Marty.

 

[martymil]

You are truly a pig in shit if I’ve ever seen one Marty.

Takes one to know one, maturity on the forums at its finest.

 

[The Convert]

Takes one to know one, maturity on the forums at its finest.

You don’t even get the reference do you?

 

[martymil]

Yes you must be as happy and carefree as me as you must know me really well to make that assumption

 

[Coupes66]

Marty, can you explain to us what is the aim/advantages behind getting the fuel density higher. Where I live in Brisbane the ambient temperatures range from max of 45 degrees C in summer to min of 0 degrees C in winter. That is the similar in Melbourne where you live. As every 10.5C change in the temperature of petrol results in a 1% change in the volume, there would be around 3% volume change between these conditions as the petrol temperature in the fuel tank wouldn’t reach those extreme temperatures. So, by starting my engine from cold at those different temperatures would mean the petrol going into the engine would be at different densities. These differences in the fuel densities will be managed by EMS through the readings coming from the O2 sensors by determining how open the injectors need to be to ensure the correct AFR is maintained. There is no power advantage that I can see by having denser fuel. With the engine already hot and starting at the above temperatures, the differences in fuel volume / density would be far less. Also, I cannot see how a maximum of 3% change in volume will make the work of the HPFP much better. I maybe missing something so please explain what I am missing.

 

[doublespaces]

I feel like there is a good gif for this thread but I can't find one.

 

[martymil]

Marty, can you explain to us what is the aim/advantages behind getting the fuel density higher. Where I live in Brisbane the ambient temperatures range from max of 45 degrees C in summer to min of 0 degrees C in winter. That is the similar in Melbourne where you live. As every 10.5C change in the temperature of petrol results in a 1% change in the volume, there would be around 3% volume change between these conditions as the petrol temperature in the fuel tank wouldn’t reach those extreme temperatures. So, by starting my engine from cold at those different temperatures would mean the petrol going into the engine would be at different densities. These differences in the fuel densities will be managed by EMS through the readings coming from the O2 sensors by determining how open the injectors need to be to ensure the correct AFR is maintained. There is no power advantage that I can see by having denser fuel. With the engine already hot and starting at the above temperatures, the differences in fuel volume / density would be far less. Also, I cannot see how a maximum of 3% change in volume will make the work of the HPFP much better. I maybe missing something so please explain what I am missing.

I live in Sydney, would not catch me dead down there.

The difference between ambient and actual fuel temp at the injector can vary a lot more than that, on a 45c day I've seen the rail reach 100c before we used
phenolic gaskets on it and opening up the cowl.

Running cooler fuel doesnt do anything for performance in terms of hp but help with fuel pressure on the hpfp rail, its not much
but every bit counts especially with rail fluctuations and I don't run a return style system.

By running cooler fuel and keeping it cool through the whole system it helps with cylinder cooling and helps with misfires and timing pull.

As I shown an earlier graph on a 43c day and the timing was dead set clean hitting 26psi on clean 93 with no e85 at all.

 

[Torgus]

For the love of god please stay on topic. We are talking about 2 inches of fuel line over the VC and how the VC can heat up the fuel rail and fuel inside of the rail and why the m18 was such a bad design you had to sell it to a customer and then install the vtt vc because it was such a better design <--This is what you claim as you are a vtt shill. The m18 design is just fine.

on a 45c day I've seen the rail reach 100c

What did you use to measure the rail temp? External rail temp does not mean the internal fuel is at that temp. At WOT fuel moves quickly enough through the system and rails.

Running cooler fuel doesn't do anything for performance

That is not true. What is true is 2 inches of fuel line above the VC with an air gap will have ZERO EFFECT ON PERFORMANCE OR FUEL TEMPERATURE. Thus the m18 VC is just fine and your statement it is a bad design is as dumb as it is false.

The minuscule temperature differences you are talking about(which do not exist because the rail is heated up by the injector, block, head, HPFP and NOT the VC) yes the fuel will do nothing for performance. Which is why saying the m18 VC was a bad design around the fuel rails is incorrect.

its not much but every bit counts

How much cooler is it? How did you measure? How do you know there is a difference? Or are you just ASSuming? How much cooler is the fuel is exactly because of 2 inch of fuel line over the VC between the different VCs? Please stay on topic.

If you saw a difference in rail fluctuations I guarantee it has NOTHING the fact you swapped VCs. That is donkey brain thinking.

By running cooler fuel and keeping it cool through the whole system it helps with cylinder cooling and helps with misfires and timing pull.

We are not talking about the whole system we are talking about how a VC can heat up fuel via 2 inches of fuel rail. There is no way 2 inches of fuel line over the VC will have ANY EFFECT on the fuel's temperature when it enters into the cylinder. Period.

As I shown an earlier graph on a 43c day and the timing was dead set clean hitting 26psi on clean 93 with no e85 at all.

Clean 93 meaning zero percent ethanol E00. I have seen you always you post that you throw in E85 at 20% to help with knock control. If you are going to post a graph post a datazap with an E content rating. Not a screen shot which could easily be manipulated.

https://bmw.spoolstreet.com/threads/vtt-gc-2-0-review.4884/ "Anything over 20 psi and max of 5 deg of timing sees massive timing corrections(on 93), I can run as low as e13 but I start to see timing corrections anything below that" At 26psi you said you need e20 and a motor running lower compression than stock otherwise you would get 'massive' timing corrections, your words. Pump 93 at stock compression vs. e20 on a motor running lower compression is a HUGE difference in terms of knock suppression.

So you want us to believe you can now run over 25% more boost now at 26PSI with zero corrections on a 110F day on 93 pump E00 when before ""Anything over 20 psi and max of 5 deg of timing sees massive timing corrections(on 93)". I call bullshit.

I actually posted about someone making a finned fuel rail on the forums as a joke. You actually are thinking it will do something? You should sell snake oil.

 

[martymil]

For the love of god please stay on topic. We are talking about 2 inches of fuel line over the VC and how the VC can heat up the fuel rail and fuel inside of the rail and why the m18 was such a bad design you had to sell it to a customer and then install the vtt vc because it was such a better design <--This is what you claim as you are a vtt shill. The m18 design is just fine.

First of all its not 2 inches of fuel line seems you dont know how the fuel system works or cant grasp it its 2 inches by 6 lines that 12 or at least 4 as the other two are somewhat exposed.

What did you use to measure the rail temp? External rail temp does not mean the internal fuel is at that temp. At WOT fuel moves quickly enough through the system and rails.

IR no contact thermometer, really how did you test that to come to that conclusion.

That is not true. What is true is 2 inches of fuel line above the VC with an air gap will have ZERO EFFECT ON PERFORMANCE OR FUEL TEMPERATURE. Thus the m18 VC is just fine and your statement it is a bad design is as dumb as it is false.

The minuscule temperature differences you are talking about(which do not exist because the rail is heated up by the injector, block, head, HPFP and NOT the VC) yes the fuel will do nothing for performance. Which is why saying the m18 VC was a bad design around the fuel rails is incorrect.

There is no airflow round the fuel lines using the m18 valve cover and adds to the temp of the lines and as the lines have the worst metal to surface area
at this point in the fuel system in terms of heat transfer and the slowest fuel movement any where in the system.

How much cooler is it? How did you measure? How do you know there is a difference? Or are you just ASSuming? How much cooler is the fuel is exactly because of 2 inch of fuel line over the VC between the different VCs? Please stay on topic.

If you saw a difference in rail fluctuations I guarantee it has NOTHING the fact you swapped VCs. That is donkey brain thinking.

Really prove it, denser fuel will have a direct correlation to rail pressure where even the tiniest unfavourable conditions will cause the rail to fluctuate.

We are not talking about the whole system we are talking about how a VC can heat up fuel via 2 inches of fuel rail. There is no way 2 inches of fuel line over the VC will have ANY EFFECT on the fuel's temperature when it enters into the cylinder. Period.

You love repeating yourself, its simple maths as in total its 12 inches of fuel line with no air movement, where the metal lines are the thinest with the greatest metal to fuel ratio in terms of heat transfer and where the fuel moves the slowest.

Clean 93 meaning zero percent ethanol E00. I have seen you always you post that you throw in E85 at 20% to help with knock control. If you are going to post a graph post a datazap with an E content rating. Not a screen shot which could easily be manipulated.

https://bmw.spoolstreet.com/threads/vtt-gc-2-0-review.4884/ "Anything over 20 psi and max of 5 deg of timing sees massive timing corrections(on 93), I can run as low as e13 but I start to see timing corrections anything below that" At 26psi you said you need e20 and a motor running lower compression than stock otherwise you would get 'massive' timing corrections, your words. Pump 93 at stock compression vs. e20 on a motor running lower compression is a HUGE difference in terms of knock suppression.

So you want us to believe you can now run over 25% more boost now at 26PSI with zero corrections on a 110F day on 93 pump E00 when before ""Anything over 20 psi and max of 5 deg of timing sees massive timing corrections(on 93)". I call bullshit.

I actually posted about someone making a finned fuel rail on the forums as a joke. You actually are thinking it will do something? You should sell snake oil.

I have no way to display e content on the graph as I do not run flex fuel and never ever will which I will not get into here but I posted that all the cylinders ticked.

I dont run E outside the city as there is no where to get it and yes you can run 93 pump with no corrections by using Nulon Pro strengh octane booster which still
makes it clean 93 with no E content, I posted about this too.

To the timing corrections we have sorted those issues out and only see small ones now and adding E to the mix is just to make the graphs look pretty as E is the easiest way to keep the graph looking clean as it doesn't add any extra cost to filling up a tank.

I'm making the fuel rail because I hate the look and design of the stock version and adding some fins to it to help lessen heat will be a plus and look better.

If you want to see me run 93 on a 110f day I posted about it including a video testing our ic and it was actually 116f that time go find it.

We always do our testing around Richmond and in the hottest part of the day at 113f and that log is our last one after we pounded on it for the last 30 minutes.

This log is on 93 with no e content and half a bottle of octane booster, so when I run 13 to 15 % E its directly comparable to US 93 fuels as almost all have some E content in one way or another.

What is next you want me to post gps tagged video.

I cant help your a doubting Thomas and will never convince you otherwise, believe what you want.

Richmond, NSW - February 2020 - Daily Weather Observations

 

[martymil]

Just to elaborate on the flex fuel setup and why I wont run it is, if you run any less than 10 to 12% E the ff module will shut off the secondary HPFP
in a double barrel setup and caused major HPFP fuel pressure loss.

So when I drive outside the city I had to basically baby the car.

Since we don't run straight e85 at all the best way to move forward was tune for straight 93 that can handle some amounts of E of 20% or less to allow for error when filling up.

You need more fuel to run the engine when the fuel has E in it and taxes the fuel system and this is really seen in a stock setup when on the limits of the hpfp.

 

[Jake@MHD]

Just to elaborate on the flex fuel setup and why I wont run it is, if you run any less than 10 to 12% E the ff module will shut off the secondary HPFP
in a double barrel setup and caused major HPFP fuel pressure loss.

So when I drive outside the city I had to basically baby the car.

Since we don't run straight e85 at all the best way to move forward was tune for straight 93 that can handle some amounts of E of 20% or less to allow for error when filling up.

You need more fuel to run the engine when the fuel has E in it and taxes the fuel system and this is really seen in a stock setup when on the limits of the hpfp.

Switch to an AIC2, splice the 0-5V FF signal wire to the DME to also go to the AIC2, and don't use the ECA tmap wires. The ECA tmap wires are meant for PI scaling and requires an appropriate AIC map.

Alternately, if you adjusted your AIC map it would also work. It can't "shut off" the second pump. It is just sending a lower scaled tmap voltage (weighted equation per E%) to the AIC and your AIC map has no output in those cells.

 

[martymil]

Thanks for that I was just following the install instructions when it first came out, stopped using it after a month or so.

If I have any issues I'll send you a msg.