High temps affecting performance ?

[Simon H]

Hi Chaps,
Does anyone think high outside temps affect the F10 M5s performance ?. Here in the UK atm, the temps are up to 30d, and im almost sure, the car is being affected by heat soak ?. Nailed it a couple of times today, and it didnt have the usual sparkle about it. Maybe im imagining it ?,regards, SIMON.

[UniqueCheese]

The science says yes. Hotter air is less dense air. Less dense air means less oxygen, and less oxygen will support less burning of fuel, and so the car will inject less, and make less power.

The real read for this will be the output of the air flow sensor. If it's lower than normal then that's what's happening.

[Tom C]

Plus with forced induction cars the ECU will pull timing and lower boost as a protective measure when the IATs are too high.

[Simon H]

Just felt like, the car didnt have its usual surge of torque, going up through the rev range. I know one of the tuners, early on in the cars release, said that the M5 suffers with heat soak, and i think i felt it a little today.

[greentrbo95gst]

Get couple nozzles and methanol tank, and spray your intercoolers to avoid heat soak. Problem solved.

[M54ccibo]

Interesting. 30C is 86F, and we have been around that all week here in South OC - and it has been humid. I haven't felt a substantial difference in performance vs. winter...but then again I am not out racing or pushing the car hard.

That said if the ambient temp is higher AND clean airflow to the radiators is compromised the car definitely has issues. This was absolutely the case on the track at COTA during the M6GC track event where the cars (both M6GC and M5) were routinely going into "safe mode" until the car determined that overheating was not going to be an issue - roughly 30sec of "D" mode driving at low RPMs where you, the driver, had no control over shifting. Ambient temps were over 90F, track temps higher than that and it was slightly humid.

[Pazzo009]

It's a catch 22. Heat affects Turbo cars more than NA cars. The downside is loss of power, the upside is gain in traction.

[wrsbmw]

Mine ran 157mph at 90F ambient outside on Sunday morning. Made a lot of speed runs from 90 to 140-150, didn't notice any slowdown and I had the AC on as well. Maybe it's the humidity. I was out in West Texas and it was dry heat.

[RPiM5]

I was driving in 102F last weekend. I didn't feel any decrease in performance. Then again I do have catless downpipes and my engine does run a little cooler.

[SANguru]

Originally Posted by greentrbo95gst

Get couple nozzles and methanol tank, and spray your intercoolers to avoid heat soak. Problem solved.

you will create much bigger problems! methanol is corrosive to aluminum. It should be used as a mixture for fuel source - not a cooling agent.

[greentrbo95gst]

Originally Posted by SANguru

you will create much bigger problems! methanol is corrosive to aluminum. It should be used as a mixture for fuel source - not a cooling agent.

http://www.alcoholinjectionsystems.c...lerPiping.html

good read.

[greentrbo95gst]

No, I've been using it on my race car.

[SANguru]

Originally Posted by greentrbo95gst

No, I've been using it on my race car.

still very corrosive. Why not just spray NOS into the intercooler?

[greentrbo95gst]

Cars have been using it for the past 10 yrs in racing and street use. You not only push cooler air through the intake manifold, but you also get the benefit of higher octane. Some people spray the front mount or side mounts with nos after driving to prevent heat soak, but you get no benefits as far as hp, it's too expensive and doesn't last long. You can use methanol while driving, or just stick with co2.

[SANguru]

Originally Posted by greentrbo95gst

Get couple nozzles and methanol tank, and spray your intercoolers to avoid heat soak. Problem solved.

reread your original post. That's not what you were saying. You said get nozzles to spray the intercooler. That's different from methanol injection into your intake path which is 2 completely different things. Spraying methanol even with a water mix will be corrosive to both the intercooler piping and the intercooler itself.

I've run meth with a JB4 tune with downpipes on my N54B30 so I know it well. Still corrosive but effective but if your main goal is just to cool down the car, the risk associated are not worth it especially on a motor that cost quite a bit more.

[Imran@Evolve]

Originally Posted by Simon H

Hi Chaps,
Does anyone think high outside temps affect the F10 M5s performance ?. Here in the UK atm, the temps are up to 30d, and im almost sure, the car is being affected by heat soak ?. Nailed it a couple of times today, and it didnt have the usual sparkle about it. Maybe im imagining it ?,regards, SIMON.

You are not wrong. The air inlet temperatures have a direct correlation to the amount of power the car makes.

Here is a dyno graph showing the inlet air temperature measured after the MAF and the resulting power.



As you can see the first and best run was at the lowest IAT. After that the drop off is significant at least on the dyno. We will carry out a similar test on the road when we get a chance but it seems as though you are already experiencing this.

You can see the video on this thread F10 M5 Stock Dyno Testing

[Simon H]

Originally Posted by Imran@Evolve

You are not wrong. The air inlet temperatures have a direct correlation to the amount of power the car makes.

Here is a dyno graph showing the inlet air temperature measured after the MAF and the resulting power.



As you can see the first and best run was at the lowest IAT. After that the drop off is significant at least on the dyno. We will carry out a similar test on the road when we get a chance but it seems as though you are already experiencing this.

You can see the video on this thread F10 M5 Stock Dyno Testing

Hello Imran,
What would be the solution to this iyo ?. I know there was mention of squirting water on the intercooler, earlier in the thread, but this isnt a Subaru or Evo. From reading the graph, does it imply, that there is around a 50 HP deficit, between first and last runs ?. Im not too bothered by this, as normal service will be resumed shortly, with the weather in this country , or do you feel that this happens anyway, after multiple WOT runs ?, thankyou, regards, SIMON.

[Imran@Evolve]

Originally Posted by Simon H

Hello Imran,
What would be the solution to this iyo ?. I know there was mention of squirting water on the intercooler, earlier in the thread, but this isnt a Subaru or Evo. From reading the graph, does it imply, that there is around a 50 HP deficit, between first and last runs ?. Im not too bothered by this, as normal service will be resumed shortly, with the weather in this country , or do you feel that this happens anyway, after multiple WOT runs ?, thankyou, regards, SIMON.

This test was carried out before the heatwave we are currently enjoying here. We will carry out similar testing on the road soon and see what the results are.

Cooling solutions will be part of our upcoming development.

Yes that is 55WHP between first and last runs. I will post up the calculated flywheel graph to show the difference.

[greentrbo95gst]

Originally Posted by SANguru

reread your original post. That's not what you were saying. You said get nozzles to spray the intercooler. That's different from methanol injection into your intake path which is 2 completely different things. Spraying methanol even with a water mix will be corrosive to both the intercooler piping and the intercooler itself.

I've run meth with a JB4 tune with downpipes on my N54B30 so I know it well. Still corrosive but effective but if your main goal is just to cool down the car, the risk associated are not worth it especially on a motor that cost quite a bit more.

Well, you should know there are couple ways of using methanol injection.
10 years later and no signs of corrosion inside or outside. It still puts out 800 whp on a mustang dyno.

[SF_E60]

Originally Posted by SANguru

reread your original post. That's not what you were saying. You said get nozzles to spray the intercooler. That's different from methanol injection into your intake path which is 2 completely different things. Spraying methanol even with a water mix will be corrosive to both the intercooler piping and the intercooler itself.

I've run meth with a JB4 tune with downpipes on my N54B30 so I know it well. Still corrosive but effective but if your main goal is just to cool down the car, the risk associated are not worth it especially on a motor that cost quite a bit more.

Are you sure you know what you are talking about? I have been building race cars for 20+ years and the corrosion you are referring too would happen over a really long period of time ONLY if you were storing methanol/water mix in a aluminum container. In this case whether you spray on the intercooler or inside of the IC piping the amount you spray dissolves within seconds and it’s not being stored in the same spot. Makes sense?

[clumsyalex]

Is is already proven that the m5 suffers from heatsoak and loses power after a couple WOT runs. There is an article on it from another bimmer enthusiast site showing before and after dynos. There was about a 50hp loss I believe. I believe I am not allowed to reference the website for some reason.

[greentrbo95gst]

Originally Posted by clumsyalex

Is is already proven that the m5 suffers from heatsoak and loses power after a couple WOT runs. There is an article on it from another bimmer enthusiast site showing before and after dynos. There was about a 50hp loss I believe. I believe I am not allowed to reference the website for some reason.

Yes, look at the dyno runs from Evolve couple posts up.