E39 M5 vs Turbo E30

[loxxrider]

Well, my buddy and I went down to Mexico recently and we have a little fun, obviously on a closed course. We tried our hardest to get some fair runs in, but it wasn't easy given the space we had.

[youtube]http://www.youtube.com/watch?v=FtbuK7uhbvA[/youtube]

[chaloux]

lol... spank show by Chris 11/12 times

[EDIGREG]

god i love mexico Is that Justin?

This can go in general automotive BTW

[loxxrider]

Yeah that is Justin! OK, go ahead and move it there, I don't think I have that ability.

[85oceanic]

Looks like a good time! Really evenly matched IMO.

[PRA4WX]

I had no idea Mexico was so close to so many people....i mean i live in AZ, and the border i still an all day drive down and back. ;-p

Thanks for vid!

[loxxrider]

Yeah you know it might be a long trip, but it is totally worth it.

I'm pretty sure the E30 would pull on the M5 if we had more room and he wasn't spinning his tires like crazy. Torque and power under the curve really makes a difference though, and I think the M5 would be faster at very high speeds just because of the difference in Cd.

[rallyfreak202]

I miss my E39 M5!!

[loxxrider]

I have some videos of my friend's drift race car... an E36 M3 with a seriously bad ass LS3. Stay tuned

[85oceanic]

[amd is the best]

The M5 sounds so glorious. I loved the sound when I went for the ride in it. Like you said, looks the E30 would have the edge but either the conditions aren't right or he needs a driver mod.

Good video!

[loxxrider]

I forgot you got to ride in it before me! It does sound rather nice. It is so quiet when you aren't on it too which is pretty cool.

Heads up, I'm still in Mexico and a new Boss 302 has called the M5 out for some video action on Thursday. There should be ample video cameras available

[amd is the best]

I forgot you got to ride in it before me! It does sound rather nice. It is so quiet when you aren't on it too which is pretty cool.

Heads up, I'm still in Mexico and a new Boss 302 has called the M5 out for some video action on Thursday. There should be ample video cameras available

Those Boss 302 are pretty badass! Looking forward to the video. I say you get some nitrous in that thing and destroy him

[loxxrider]

haha great idea!

It is my uncle's car and I've driven it. I don't remember exactly how it felt, but the two cars are relatively comparable. With more hp, torque, and less weight, I think the obvious answer is that he'll win. It'll still be fun though. Also, the M5 suffers severely from heat soak and gets quite sluggish (relatively speaking) when temps are higher than about 70 F which totally sucks since I live in FL lol. It's like there is a big retard in timing when it gets to a certain temp in the intake tract (at 75 F outside last night it was reading 110 F at the MAF according to the super duper sensors I installed for an experiment). Meth would be a very good addition to this car if the nozzle was placed such that the temp sensor could read the decreased intake temps. I honestly think (and others agree) that the car loses at least 30 ft*lb or hp in warmer conditions.

[amd is the best]

haha great idea!

It is my uncle's car and I've driven it. I don't remember exactly how it felt, but the two cars are relatively comparable. With more hp, torque, and less weight, I think the obvious answer is that he'll win. It'll still be fun though. Also, the M5 suffers severely from heat soak and gets quite sluggish (relatively speaking) when temps are higher than about 70 F which totally sucks since I live in FL lol. It's like there is a big retard in timing when it gets to a certain temp in the intake tract (at 75 F outside last night it was reading 110 F at the MAF according to the super duper sensors I installed for an experiment). Meth would be a very good addition to this car if the nozzle was placed such that the temp sensor could read the decreased intake temps. I honestly think (and others agree) that the car loses at least 30 ft*lb or hp in warmer conditions.

Nitrous would cool it down pretty well too . Time for Marc to build a VEMS for the M5 too, lol.

Side note, 40 degrees warmer at the MAF seems really high. Think that is normal?

[loxxrider]

Yeah, it's one thing to flirt with blowing up an engine like the 5-cyls we play with where it is relatively easy to re-build and parts are relatively cheap. I don't even want to think about what one wrong nitrous spray would do to my wallet with the M5 engine! I am much more comfortable with forced induction

It does seem incredibly high doesn't it? There is a camp of people with these cars who relocate their temp sensors to the intake trumpets just behind the front bumper. They do this because they believe the stock IAT sensor located in the MAF housing gets heat-soaked and reads too high, thus robbing the engine of power. I have always been wary of this idea since the MAF housing and any attachments the sensor has are all plastic which isn't exactly a very conductive material.

I couldn't stand not to know for myself, so I have mounted sensors in the engine bay next to the MAF, inside the actual MAF housing, and where people sometimes relocate the sensor. The relocated sensor essentially always reads roughly ambient temperature. The engine bay temp sensor was reading up to about 160 F and the one inside the MAF was reading around 110 when everything got warmed up. Unless my diode-based sensor is getting heat-soaked too which I doubt since it is insulated with heat shrink and silicone and sits more than an inch into the housing, then the air really does get that hot there. You can see the temp go way up when I shut the car off in the log in two places and then come back down pretty quickly when I start the car back up. That says to me that the sensor is not getting heat-soaked. This is getting a bit off-topic, but oh well. Attached below is a graph I made from last night if you are interested.

The log is basically me starting the car up completely cold at 75 F ext. temp and then driving to the gas station and back. It had fully warmed up just as I got to the gas station and you can see where engine bay temp drops as I get up to speed on the main road just before getting there too. Then I shut it off while filling up with gas and you can see that where temp 1 and temp 2 rise. Then I get on my way home and temps generally drop back down until I pull into the garage (as seen with increase in sensor 1) and mess with the logging and sensors for a minute or two.

Disregard how noisey the log is... I have to figure that out and fix it. The sensors are supposed to be accurate to about +/- 2 deg F though.

[alxdgr8]

Is that plot from excel?!? You're an engineer, I should see a MATLAB figure not excel!

[amd is the best]

Very cool that you actually logged this data! I honestly had no idea what normal under-hood temps were like, just seemed high to me. Relocating those sensors would probably increase the power however the engine is still getting warmer air then what is being read. It's only tricking the ECU to keep the tune more aggressive, when the programming clearly wants it to be more mellow. Are they being way to conservative, maybe. Is it unsafe to trick the ECU, doubtful.

I was only kidding about the nitrous, though it does work well. Way too much money to fill, and like you said an M5 engine is almost certainly not a cheap item.

[loxxrider]

Ha! That would require way too much work! I need to get MATLAB on my computer again now that I think about it.

The data was collected in LabView and then exported via a tab-delimited file, so excel was the easiest solution.

I never understood why some engineering professors hate excel plots so much. They can be made to look nice enough if you know what you are doing. Sometimes the MATLAB ones are just ugly haha.

Very cool that you actually logged this data! I honestly had no idea what normal under-hood temps were like, just seemed high to me. Relocating those sensors would probably increase the power however the engine is still getting warmer air then what is being read. It's only tricking the ECU to keep the tune more aggressive, when the programming clearly wants it to be more mellow. Are they being way to conservative, maybe. Is it unsafe to trick the ECU, doubtful.

I was only kidding about the nitrous, though it does work well. Way too much money to fill, and like you said an M5 engine is almost certainly not a cheap item.

Yeah, they do make more power with the sensor relocated, but then they essentially relying on the knock sensors to control timing. I don't like that idea a whole lot. I do think it is possible that the stock tune is probably conservative in this area, but I'd rather be safe than sorry. If I lived in a more moderate climate I would be more inclined to trick the ECU, but when it gets 95 F and 95% humidity here, I'm just not very comfortable with it... especially when we are talking at least 30 F differences in intake temp. That is at least a few degrees of timing worth of retard.

It is definitely a very interesting subject to explore, but one would have to know much more about the stock ECU tune and do more testing than I really have time for. I am just happy to know that it does get damned hot in the intake tract and that I'd just like to play it safe! I just don't like relying on knock sensors entirely for det control since there isn't a reliable MAT vs. timing retard table reference after relocating the sensor.

[chaloux]

Time for a big ass hood scoop!

[alxdgr8]

I use Excel and MATLAB both everyday, I just wanted to give you some crap One of my coworkers use to work at Mathworks and won't even touch Excel for anything!
What hardware did you use with Labview? Sample rate?

[loxxrider]

Lol I know, we used to get crap all the time for it even in a class I graded papers in. I never took off points for that

I use an NI USB6009 14 bit DAC for this kind of thing. Simple, eas and very effective. Sample rate was as fast as it would run which was just over 1 ms per sample, almost 1000 hz.

[WOMBAT]

You bought yourself an NI USB6009 and LabView? Geek out!

[loxxrider]

lol yeah! Gotta geek out every once in a while! I did have to use it for school too though.

[PRA4WX]

I thought there was a promise of vids with the Boss in Mexico....it is Thurs, right?!