On track with arrow vs stock pcm, coolant temp 👍 Or 👎

[Utahviper]

I went to miller motorsports park or UMC east track. This is the same place that we had voi 11. Last Thursday it was 90 degrees ambient. I brought both pcm's. First, arrow was at 240 degree coolant temp after 5 laps, one of those was a warm up lap. Next session, 30 min later, stock pcm, full 22 min session, highest temp on last lap was 235. The stock pcm never got above 235 at any other session. Verdict, at least at my track, the ambient must be in low 80's or high 70's to use the arrow pcm. The stock pcm is golden👍

https://m.youtube.com/watch?v=eNS7TS...st_app=1&app=m

[Dave1968]

So what about the rest of the story. 5 degrees is nothing. How did they stack up on the course overall and how did they feel.

[donk_316]

Imagine that... Engine that makes more power runs hotter by a whole 5 degrees

[mnc2886]

Imagine that... Engine that makes more power runs hotter by a whole 5 degrees

Exactly. Engines that make more power generate more heat. I'm not finding the relevance of this thread without lap times.

[Rapidrezults]

5 degrees is not the point.

As I see it he didn't want to push past 240 on the 5th lap with the Arrow PCM, which I would assume is much less than a full 22 minute session...so he put the stock PCM in and solved the problem. This is great information, and backs up what others have said in a less provable way.

[Utahviper]

Guys, sorry I didn't finish the story. The arrow is faster by .5 seconds but I can't run but half the time. I can run an entire session with the stock pcm and not overheat. The video I posted is with the stock pcm. If you can only run 9 minutes per session, it's definitely relevant. I'm just posting the info for the masses to know that some of the overheating issues can be due to the arrow Pcm.

The feel of the pcm differences is hard to feel on the track. It's hard to feel the power difference as well.

When the weather is cool, I'm running the arrow. When the weather is warm, I'm running the stock Pcm. If I was on the track by myself or little traffic and trying to run a qualifying lap or the like, I will run the arrow.

[TrackAire]

Excellent feedback from real world experience. Miller is at least 4000 ft in elevation IIRC, so between the dry desert air and warm ambients it is a hard track to keep a lot of different cars cool at.

So tuning gurus, is the main difference that the Arrow pcm runs leaner causing more heat?

[FLATOUT]

So did you overheat or just pit because you saw 240? Dick has said more than once that the temps are fine there.

[Jack B]

The stock pcm bends over backwards to keep the engine on the ultra safe side. As was stated above, the stock pcm does not make as much power as the Arrow pcm.. The stock pcm pulls large amounts of timing when it sees high coolant and IAT temps, that is where your diff is, the stock pcm is reducing the hp far more than the Arrow pcm in high temps. Secondly, the stock pcm also adds fuel as it pulls timing when encountering the higher temps, again, robbing power. A super rich mixture also tends to cool the combustion chamber. As was stated above, more hp equals more heat to transfer.

Excellent feedback from real world experience. Miller is at least 4000 ft in elevation IIRC, so between the dry desert air and warm ambients it is a hard track to keep a lot of different cars cool at.

So tuning gurus, is the main difference that the Arrow pcm runs leaner causing more heat?

[Utahviper]

So did you overheat or just pit because you saw 240? Dick has said more than once that the temps are fine there.

When something is blinking red, I generally let off or pit. I don't like to run things on the ragged edge. I'd rather be safe than sorry. Btw, I installed the arrow before we left. I have no problems with it anywhere else except when there is high ambient temp at the track.

[Bruce H.]

It sounds like 240 caused a blinking warning which would make me pit as well unless Dick was there telling me to hammer on. But if 240+ is safe then what I'd want to know is how much higher the temps would have gone if you had run a full session like with the stock PCM. Would max temp have plateaued at a still safe level or kept climbing to dangerous levels...big difference. Would also like to know how your experience would relate to similar ambient temps at elevations closer to sea level.

[FLATOUT]

When something is blinking red, I generally let off or pit. I don't like to run things on the ragged edge. I'd rather be safe than sorry. Btw, I installed the arrow before we left. I have no problems with it anywhere else except when there is high ambient temp at the track.

I understand, but it has has been discussed before here that Dick said the motors fine there red light or not. Shifting 200rpm sooner most likely will drop the temps a little as well. A little Mo Cool in the system doesn't hurt either. These are just suggestions if you WANT to run that PCM in the hottest months of the year. I haven't had any issues running in the Texas heat but I'm very cognizant of when temps are rising and why. I'll make small adjustments in my driving without losing much if any time in a session.

[Rapidrezults]

The magic question, is it worth running your car beyond the 240 mark, and for what actual gain? In an HPDE setting this would be senseless. Also, have fun explaining to the service department if you encounter any major issues while out on track that you were running 240+, ignoring the red light etc etc. Just running an Arrow PCM on track is gambling with your warranty enough.

[donk_316]

The magic question, is it worth running your car beyond the 240 mark, and for what actual gain? In an HPDE setting this would be senseless. Also, have fun explaining to the service department if you encounter any major issues while out on track that you were running 240+, ignoring the red light etc etc. Just running an Arrow PCM on track is gambling with your warranty enough.

The guy who programmed the Arrow PCM is the same guy who programmed your stage 2 PCM.

[Rapidrezults]

The guy who programmed the Arrow PCM is the same guy who programmed your stage 2 PCM.

Yeah, I'm also running under a different set of circumstances should my motor decide to take a sh*t. I can run at 250+ and it doesn't matter because nobody is going to deny me a claim on a warranty that I don't have anymore. Lol. All I'm saying is if I were going to track my relatively stock car, I'd be running a stock PCM and not taking a risk of warranty denial for a 20hp gain.

[Dave1968]

Quick question - which hood do you have?

[Utahviper]

As far as I know, TA 2.0 only come with srt hoods.

[Arizona Vipers]

Did you have to have the dealer reprogram anything when switching from the arrow to stock pcm?

And yeah 5 degrees difference at the track is HUGE as that's the difference from having to pull off early or not.
The dash starts flashing at high 230's for me and that's when I pull off.

[Utahviper]

I had the dealer install the pcm and told them not to update anything. I was worried about them reflashing the pcm accidentally. Was I supposed have them reprogram something? We just followed the instructions that came with the Pcm. Everything works great, just gets a little warm on hot track days.

Btw, nice garage 👍

[ViperGeorge]

The coolant temp warning light comes on at 240. I've hit 243 in my TA 2.0. A friend in a stock GTS was running 238 on the same day, same 5 degree difference. My oil was 265. Altitude was about 5000 feet. Even Arrow controller will begin to pull timing at those temps. I ran multiple tests and the results are detailed in another thread. Page 5 of this thread - http://driveviper.com/forums/threads...ck+overheating

The Gen 5s simply do not run as cool as the Gen 4s. That's a fact. And yes, I'm with those that say if the warning light is flashing I'm slowing down or pulling off. Slowing down for a lap will bring temps down quickly but then they rise again quickly when you get back on it. Someone should develop a real solution to this!!!! Come on Viper vendors come up with something to cool the damn cars off. My old 09 ACR never ever ran more than 210 on the track and these temps on a Gen 5 is my biggest complaint with the car (ok, and I don't like the seats either).

As anyone tried one of those waterless coolants such as Evans?

[steve911]

I know that Snakeoyl/Viper Parts USA is working on an upgraded radiator.

The other problem is that the grill opening is smaller than on the Gen 3-4 cars. I am exploring the possibility of relocating the PS steering cooler to the backside of the radiator like the Comp Coupes are. Moving the cooler will make a difference I am sure.

[Arizona Vipers]

I had the dealer install the pcm and told them not to update anything. I was worried about them reflashing the pcm accidentally. Was I supposed have them reprogram something? We just followed the instructions that came with the Pcm.

Btw, nice garage ��

I thought that the dealership had to reprogram the throttle position or something similar. Anyone here know?

[ACR Steve]

Steve911- remember its not necessarily the front side of a radiator. The back side is where you get the flow from

[Darius]

I run the Arrow pcm and could only manage 3 to 4 laps before the red light starts blinking. My buddy was running the same day same car stock pcm never saw above 234. I also don't feel like risking it on the Arrow so the next track day the stock pcm is going back in.

[docwviper]

Crazy. I dont't have this issue with the arrow PCM. However, I also have the shelby intake shield which I think helps alot.