Heat Soak Issues with M3/M4?

[FTS]

Originally Posted by SYT_Shadow

i'd say so. It gives an idea of how hard someone is tracking the car.

A car cannot be driven at 10/10ths without supporting goodies. Just as a better driver consumes more gas per session than a newbie, having better hardware allows you to push the car further

As I said earlier, I want to believe.

I disagree with you, driving the car 10/10th does not have anything to do with what the car has or hasn't. You drive what you have to the limits, although let's not claim we really actually do so

You, your brother and I met at Summit Point during our PCA event, I think it was in July or close to that. You guys are good drivers, but you probably know by now that there were quite a bit fast drivers on the track with their stock cars

Any ways, I understand your point, but you need to slightly modify your thinking IMHO that to go fast or push the car to limits does not require all those track goodies. At the same time, I do agree that we haven't seen all there is to see with this new car, IMHO that will not happen for another couple of years of wear and tear is built into the cars on the track. Until then, you may want to stick to that gorgeous E46 M3.

Keep it safe on the track as you guys have been doing, and see you next season again hopefully.

[SYT_Shadow]

Originally Posted by FTS

I disagree with you, driving the car 10/10th does not have anything to do with what the car has or hasn't. You drive what you have to the limits, although let's not claim we really actually do so

You, your brother and I met at Summit Point during our PCA event, I think it was in July or close to that. You guys are good drivers, but you probably know by now that there were quite a bit fast drivers on the track with their stock cars

Any ways, I understand your point, but you need to slightly modify your thinking IMHO that to go fast or push the car to limits does not require all those track goodies. At the same time, I do agree that we haven't seen all there is to see with this new car, IMHO that will not happen for another couple of years of wear and tear is built into the cars on the track. Until then, you may want to stick to that gorgeous E46 M3.

Keep it safe on the track as you guys have been doing, and see you next season again hopefully.

I really enjoyed Summit, I will definitely be back next year and we can meet again

You make good points and I probably should have explained myself better in the first post

One can drive any car to the limit, and I agree it is rare for a regular driver to know when they're there. While I was spinning after the bus stop at WGI this year I thought 'there's the limit!' ha. However, it would be erroneous to say I have reached the limit of the engine/cooling system even when I have reached the limits of the tires.

What I was getting at is the rate at which you consume gasoline, tires, brakes etc depends on how hard you drive and after that point on your setup. The percentage of time on throttle depends a lot on how sticky your tires are, etc.
It is impossible to max an engine out without full slicks and a long list of etcs. The cooling system will not see the maximum production of heat until someone tracks it with a better setup than stockish.

The E46M has harnesses (safety), stock suspension, slightly upgraded brakes and camber plates so I definitely believe one can improve tracking very stockish cars, however, because my E46 does not overheat probably has to do with me not pushing it as much as others do even though my instructors seem to agree I need to move on to stickier tires as I'm at the limit very frequently with the RS3s.

[FTS]

Originally Posted by SYT_Shadow

It is impossible to max an engine out without full slicks and a long list of etcs. The cooling system will not see the maximum production of heat until someone tracks it with a better setup than stockish.

You may not be thinking with these specific words, but I think you are asking or waiting to find out "what is the breaking point for this engine?"

I can appreciate the thought on this, but these are street cars, not race cars. I do not know for a fact, but I doubt even the platform is good enough to be a race car, I hope I am wrong. My advice is to keep expectations to realistic levels and not expect the car to perform at levels that some are expecting. I might be proven wrong of course in due time.

Originally Posted by SYT_Shadow

The E46M has harnesses (safety), stock suspension, slightly upgraded brakes and camber plates so I definitely believe one can improve tracking very stockish cars, however, because my E46 does not overheat probably has to do with me not pushing it as much as others do even though my instructors seem to agree I need to move on to stickier tires as I'm at the limit very frequently with the RS3s.

You guys were definitely held back with the RS3s from what I observed. At the same time, I would not recommend slicks for any street-based car, too much stress on the chassis and suspension, especially one that is driven to/from track and not trailered.

[SYT_Shadow]

Originally Posted by FTS

You may not be thinking with these specific words, but I think you are asking or waiting to find out "what is the breaking point for this engine?"

I can appreciate the thought on this, but these are street cars, not race cars. I do not know for a fact, but I doubt even the platform is good enough to be a race car, I hope I am wrong. My advice is to keep expectations to realistic levels and not expect the car to perform at levels that some are expecting. I might be proven wrong of course in due time.


You guys were definitely held back with the RS3s from what I observed. At the same time, I would not recommend slicks for any street-based car, too much stress on the chassis and suspension, especially one that is driven to/from track and not trailered.

Ha you read my mind.

You have a point, it is not a 'race car'. I hope it's cooling system is good enough for serious track use.

Next season I'll start using NT01s. Without suspension I won't go into something like the PSC2 and anyway my driving level is not there (yet!)

[CanAutM3]

Originally Posted by FTS

How does different suspension, brake pads and tires make a difference with heat soak of engine components?

I would say because these goddies allow you to spend more time at WOT, which will inherently put more heat into the engine.

I don't dissagree with SYT_Shaddow, the true test for me will be when I try out my car in track gear on a hot summer day. That being said, my present experience with the car is that there seems to be sufficient reserve/margin with the cooling system. Time will tell.

[FTS]

@CanAutM3, I think I understand that; however...

First the disclaimer: I know very little about engines, so there is a good chance I may be wrong about my assumptions.

Now... I hope you have had a data logger in your car, if so and you have been running stock during your first events, once you make changes to your car, compare the data. The actual WOT vs. partial throttle time. I would imagine total WOT per lap will be less than 1 sec. Let's suppose you do 10-15 laps per session that would be 10 to 15 secs per session.

Do you really think 15 secs more @ WOT, non-contiguous, will make a difference with heat soak? I think, may be erroneously, that a more deterministic test would be running track sessions during high ambient temps (90+ F or 30+ C), high humidity and high altitude (lower air pressure env.). Would you disagree?

[CanAutM3]

Originally Posted by FTS

@CanAutM3, I think I understand that; however...

First the disclaimer: I know very little about engines, so there is a good chance I may be wrong about my assumptions.

Now... I hope you have had a data logger in your car, if so and you have been running stock during your first events, once you make changes to your car, compare the data. The actual WOT vs. partial throttle time. I would imagine total WOT per lap will be less than 1 sec. Let's suppose you do 10-15 laps per session that would be 10 to 15 secs per session.

Do you really think 15 secs more @ WOT, non-contiguous, will make a difference with heat soak? I think, may be erroneously, that a more deterministic test would be running track sessions during high ambient temps (90+ F or 30+ C), high humidity and high altitude (lower air pressure env.). Would you disagree?

I probably was not precise enough in my previous post. IMO, with go-faster goodies, you will spend more time with bigger throttle openings, not only more time at WOT as I originally posted. If you can sustain higher cornering speeds, you need more throttle input to sustain that speed. With more grip, you can apply more throttle earlier at track out; not only will you be at WOT earlier, but you will have applied more throttle through the entire turn. The additional power the engines needs to dish out over the course of a full lap does add up. On my E92, I certainly felt I was putting more stress on my engine when pushing it on r-comps relative to pushing it on street tires. But it is all very subjective, I have never compared data logs.

I agree though, a hot day will make it even more difficult to extract the heat.

[SYT_Shadow]

Interesting discussion. Glad you see the point I was trying to make CanAutM3

In the E46M at least I spend many more than 10 seconds per lap at WOT. Leaving turns while tracking out, accelerating until the next turn, then main straights... there is significant WOT use

I agree that it seems to be robust. As this is a full M car I did not expect any less. I think I will be joining you guys next year

[thebishman]

Originally Posted by SYT_Shadow

Interesting discussion. Glad you see the point I was trying to make CanAutM3

In the E46M at least I spend many more than 10 seconds per lap at WOT. Leaving turns while tracking out, accelerating until the next turn, then main straights... there is significant WOT use

I agree that it seems to be robust. As this is a full M car I did not expect any less. I think I will be joining you guys next year

I think that on most road courses you are at WOT from >70% of the time?

Bish

[FTS]

Originally Posted by CanAutM3

I probably was not precise enough in my previous post. IMO, with go-faster goodies, you will spend more time with bigger throttle openings, not only more time at WOT as I originally posted. If you can sustain higher cornering speeds, you need more throttle input to sustain that speed. With more grip, you can apply more throttle earlier at track out; not only will you be at WOT earlier, but you will have applied more throttle through the entire turn.

I know I am speculating since I have no data show with the F8x, so I apologize for over-reaching. At the same time, the difference in bigger throttle applications is so insignificant that someone should not judge whether a car is driven hard based on the mods on the car. Even using 4 secs of more throttle at or near the last batch of RPMs per lap for 15 laps only amounts to 60 secs total per session. If those 60-80 secs are run at 60 degF ambient, it won't/shouldn't have much effect IMO; if ambient is 90 degF+ it will make a difference.

Originally Posted by SYT_Shadow

In the E46M at least I spend many more than 10 seconds per lap at WOT.

The issue is not the 10 secs, although unless you are driving a Miata, to have 10 secs of WOT you must be talking about WGI or something similar, may be VIR. Regardless, my point is not around the 10 secs of WOT, it is around the X in [10 (stock car) + X (improvements with goodies)]. If you think that X will be so large that it will change the heat soak equation (not oiling, that's different), I think you'll come to the wrong conclusion, positive or negative.

I hope I am not wrong, otherwise this car will be a huge let down

[robbo mcs]

If you go faster, that means you have used more energy / burnt more fuel to go faster. That means more heat has been produced and has to be dissipated by the engines cooling systems. Also faster laps times means less time off throttle, which is less time for the cooling system to recover.

I have a dedicated circuit racing car, which is a BMW marque turbo model. When the air temps are cool all is fine. When it is warm, a difference of 1-2 seconds a lap can mean the difference between overheating water and oil temps and normal in range temps. When the water temps get hot, backing off the pace by 1-2 secs a lap brings it back into range.

My point is, the faster you go, the harder you push the cooling system. That might be water temps, oil temps or even intake temps, or all of the above. In my racecar I have found the limit.

Nobody has found the limit in the F80/82 yet. However, I agree, until someone is breaking lap records on good suspension, race brakes and type R tyres or slicks etc, we won't really know where the limit for this car is, and how much headroom we have

My overall impression is that the cooling capacity for this car is probably very high. It seems to be engineered well, with a lot of headroom.

Now, if we start talking about tuned engines, with more boost, bigger turbos etc, then almost certainly people will start to run out of headroom.

What we do know about the F80/82 is that in completely stock form you can drive very hard on the track without heat problems. This is not the case for all cars.

[CanAutM3]

Originally Posted by robbo mcs

What we do know about the F80/82 is that in completely stock form you can drive very hard on the track without heat problems. This is not the case for all cars.

Bingo, that is exactly it

[nicknaz]

Originally Posted by robbo mcs

What we do know about the F80/82 is that in completely stock form you can drive very hard on the track without heat problems. This is not the case for all cars.

I love posts like this.

I have been holding off on my F80 order since I've easily gotten my stock E89 Z435i (300F oil temp) and F30 335 (290F oil temp) with factory oil coolers to go to power reduction here in SoCal and have been doubting stock BMW ability to appropriately cool a turbo car used for HPDE.

The Z435 even got DCT issues once where it would automatically upshift 4000rpm

With all the positive track reviews for stock F80 with better tires and brake pads that's taken a huge objection off the table for me.

[MaynardZed]

Originally Posted by thebishman

I think that on most road courses you are at WOT from >70% of the time?

Bish

Huh? What do u drive, a go cart?

[Dalko43]

Originally Posted by nicknaz

I love posts like this.

I have been holding off on my F80 order since I've easily gotten my stock E89 Z435i (300F oil temp) and F30 335 (290F oil temp) with factory oil coolers to go to power reduction here in SoCal and have been doubting stock BMW ability to appropriately cool a turbo car used for HPDE.

The Z435 even got DCT issues once where it would automatically upshift 4000rpm

Neither the Z4 35i nor the F30 335i was designed with track duty in mind. The Z4 35i, even though it has the same engine as the 1m, is lacking the additional oil cooling that the N54 engine is sorely in need of during high performance use.

[nicknaz]

Originally Posted by Dalko43

The Z4 35i, even though it has the same engine as the 1m, is lacking the additional oil cooling that the N54 engine is sorely in need of during high performance use.

yes, I unfortunately found that out after the fact

I didn't do enough research to understand the Z435 was a TT/SLK competitor and not a Boxster competitor.

Oh well, that's why Z435 is heading out the door soon.

[jerseygirl]

Originally Posted by redz06

Just wondering if any of you that have already tracked your new M3/M4 have noticed any heat soak issues with the engine performance. I definitely experienced this with my 335i sedan (Nordschleife), and swore to myself that I would check on this before buying another turbocharged car. My 335i was obviously suffering power loss after only one lap of the 'ring.

I have not seen any mention of this in the published testing, but I did not see any warning of it on the 335i track tests either. Obviously some reviewers don't want to say negative things about their cars. In the case of my 335i, I think that all it needs is a larger intercooler.

With spirited street driving, there is never a problem.

Anyone been tracking their new M3/M4 that can give me a definitive answer?

what exactly is heat soak? my 335 had "fuel pump malfunctions" one after another. moved to M3 to get out of turbo. are you saying there is a defect where the care goes into limp mode?

[CanAutM3]

Originally Posted by jerseygirl

what exactly is heat soak? my 335 had "fuel pump malfunctions" one after another. moved to M3 to get out of turbo. are you saying there is a defect where the care goes into limp mode?

Heat soak is when the intake system gets saturated with heat which yields the air entering the engine getting hot. Hot air is less dense, so the engine makes less power. Further, when the intake charge is hot, the engine becomes more prone to detonation and the engine ECU will pull back on timing, therefore also reducing power.

Normally aspirated engines can also get heat soaked, when the engine compartment get so hot, the intake tract, air filter housing and intake plenum also get very hot. But forced induction engines are more prone to this, because the compressor heats up the air as it increases its pressure. The intake system can therefore quickly become saturated with heat when running continuously at full power if the heat extraction capabilities of the intercooler system are insufficient.

The fuel pump issues you had with your 335 are likely to be unrelated to what is commonly referred to heat soak.

[jerseygirl]

Originally Posted by CanAutM3

Heat soak is when the intake system gets saturated with heat which yields the air entering the engine getting hot. Hot air is less dense, so the engine makes less power. Further, when the intake charge is hot, the engine becomes more prone to detonation and the engine ECU will pull back on timing, therefore also reducing power.

Normally aspirated engines can also get heat soaked, when the engine compartment get so hot, the intake tract, air filter housing and intake plenum also get very hot. But forced induction engines are more prone to this, because the compressor heats up the air as it increases its pressure. The intake system can therefore quickly become saturated with heat when running continuously at full power if the heat extraction capabilities of the intercooler system are insufficient.

The fuel pump issues you had with your 335 are likely to be unrelated to what is commonly referred to heat soak.

thanks great response!

[Straight flexin]

Originally Posted by CanAutM3

Heat soak is when the intake system gets saturated with heat which yields the air entering the engine getting hot. Hot air is less dense, so the engine makes less power. Further, when the intake charge is hot, the engine becomes more prone to detonation and the engine ECU will pull back on timing, therefore also reducing power.

Normally aspirated engines can also get heat soaked, when the engine compartment get so hot, the intake tract, air filter housing and intake plenum also get very hot. But forced induction engines are more prone to this, because the compressor heats up the air as it increases its pressure. The intake system can therefore quickly become saturated with heat when running continuously at full power if the heat extraction capabilities of the intercooler system are insufficient.

The fuel pump issues you had with your 335 are likely to be unrelated to what is commonly referred to heat soak.

Well said. Here's the truth. I have an f80 m3. It's a turbo car. It will heat soak. Anyone that says it doesn't, just isn't driving
It hard enough. The only way to counter this will be with octane. I was using 91 and was able to get 2 laps this summer with the same power I entered the pits with. After 4 laps I was so down on power I wasn't making it out of 4th gear anywhere and came
Back in. I tried 100 octane and
It definitely improved the issue of more consistent power. My bet is that e85 would improve this even more.

[CanAutM3]

Originally Posted by Straight flexin

It will heat soak. Anyone that says it doesn't, just isn't driving It hard enough.

2 back to back 30 minutes session on a race track at full boil is not driving it hard enough

Yet I have not experienced heat soak.

Originally Posted by Straight flexin

It's a turbo car. It will heat soak.

That is not a given. If the heat extraction capabilities are sufficient, there is no reason for it to heat soak.

Originally Posted by Straight flexin

The only way to counter this will be with octane.

That is an interresting and valid point. I was running 94 because it is readily available here That could be the reason BMW recommend running at leat 93 (with 91 being the bare minimum).

[MaynardZed]

Originally Posted by CanAutM3

2 back to back 30 minutes session on a race track at full boil is not driving it hard enough

Yet I have not experienced heat soak.



That is not a given. If the heat extraction capabilities are sufficient, there is no reason for it to heat soak.



That is an interresting and valid point. I was running 94 because it is readily available here

Yeah, it's a good thing they never use turbocharging in race cars because they would always heat soak too.