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Old 10-08-2017, 09:48 PM   #2276
Pelco
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Throttle Happy 87/89 on a 2016 CVT sport. Manual mode pull.
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Old 10-09-2017, 03:02 AM   #2277
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Quote:
Originally Posted by Pelco View Post

Throttle Happy 87/89 on a 2016 CVT sport. Manual mode pull.
Recommend that you make another screen with only HP and Torque measurements to maximize accuracy per Torque website instructions.
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Old 10-09-2017, 07:35 AM   #2278
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Boost display on an NA car... that's useful.
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Old 10-10-2017, 12:02 PM   #2279
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Quote:
Originally Posted by bobdole888 View Post
Recommend that you make another screen with only HP and Torque measurements to maximize accuracy per Torque website instructions.

I ran my own test with only HP and Torque on Torque screen, 3400lb for car weight, and TH rev5b 91/93 tune with 91 gas. (2012 limited wagon)
Results are 122 HP, 109 ft-lb torque. (spec 148 hp, 145 torque)

These results seem more believable than the 150 torque reported earlier.
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Old 10-11-2017, 10:07 PM   #2280
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I got 100 HP and 109 ft-lb. Hp seems a bit low? On TH rev5 87 tune.
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Old 10-12-2017, 12:07 AM   #2281
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Originally Posted by binnkim View Post
I got 100 HP and 109 ft-lb. Hp seems a bit low? On TH rev5 87 tune.
What did you enter as the weight of the car?
I put in 3400lb. This number might be on the high side, so maybe my numbers are optimistic.

Also, are you running rev_5b or just rev5?
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Old 10-12-2017, 09:22 AM   #2282
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Quote:
Originally Posted by bobdole888 View Post
What did you enter as the weight of the car?
I put in 3400lb. This number might be on the high side, so maybe my numbers are optimistic.

Also, are you running rev_5b or just rev5?


I put in 1450kg - a lot lower than your car. I will try again tonight.

Iím on rev 5a.
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Old 10-12-2017, 01:53 PM   #2283
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Originally Posted by drpoop View Post
Boost display on an NA car... that's useful.
Yes I know. I didn't put it there to see boost. Duh.

But I was reading about negative engine pressure. By default NA, turbo and supercharger cars have negative air pressure while the engine is running. But when you push the car, that negative pressure actually starts to equalize to 0. In a turbo or super charger engine this would start to build positive pressure and you get the kick.

My purpose for displaying engine pressure was to see at which point in my RPM range, I get the least amount of pressure and sustain it with the throttle. That to me would mean my engine would be working more efficiently.

I could be totally wrong about this but it's an interesting metric to consider against all the other variables.
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Old 10-12-2017, 01:56 PM   #2284
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200Nm= 147.5124ft-lb

This is a rev5 tune on 87octane.
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Old 10-12-2017, 03:01 PM   #2285
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kek, now you know it's completely wrong. Even Torque says it's supposed to measure whp/tq not flywheel.
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Old 11-21-2017, 07:33 AM   #2286
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So it has been a while since anyone talked about their tune. I put the stock tune back in and have been driving for a while now. It's fine, I am very used to the pedal and engine ramp up slope. I changed it back to stock after tuning 5A for a while and found the acceleration curve to be foreign.



My question for those who use the 91 octane tune.

Since the engine was designed as a lower compression engine to use regular fuel, how can it make use of 91 octane? Can the ECU timing alone be enough?

I mean, it can't actually change the physical compression can it?

I understand that the timing affect when the spark fires, but the compression itself will never exceed or in my mind warrant the use of high octane fuel.

Please help me understand how it works.

Also how is your 5A/X tube treating you?

My car with the stock tune and colder weather is really happy. But I wonder if there are noticeable gains to be had with 91 octane and TH's 5A tune.
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Old 11-21-2017, 08:09 AM   #2287
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Compression ratio isn't that low for a normal multi port injection at 10.5:1, but it is all aluminum which does help run higher compression with lower octane.

Is it mostly timing i think, but it does work.

I have been tempted to try 3a in 87 flavor, have to double check i have that option, but i have been running the 91 tunes and been happy
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Old 11-21-2017, 09:03 AM   #2288
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I’m the complete opposite. I ran the stock shop tune for a couple weeks and couldn’t stand the way it drives.

I run the 91/93 tune with 93 now and I’m really happy. Totally different car for me anyways. Do you have a CVT? I do, that could be the difference

Last edited by Angelus911; 11-21-2017 at 10:31 AM.
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Old 11-21-2017, 09:24 AM   #2289
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Quote:
Originally Posted by Pelco View Post
My question for those who use the 91 octane tune.

Since the engine was designed as a lower compression engine to use regular fuel, how can it make use of 91 octane? Can the ECU timing alone be enough?

I mean, it can't actually change the physical compression can it?

I understand that the timing affect when the spark fires, but the compression itself will never exceed or in my mind warrant the use of high octane fuel.
I've wondered the same thing, but I'm pretty sure when the spark fires is really the only difference. To my understanding, the higher the octane, the more it needs to be compressed before being sparked.

To me, there is an implication that the engine was built with enough room to handle higher-octane fuel. What doesn't make sense to me is if Subaru never intended these engines to use higher compression, wouldn't that mean the distance at which the pistons move is excessive, and therefore wasteful/inefficient?
Hypothetically, let's say that for 87 octane, the piston only needs to stretch out 95% of the way until the mixture is compressed enough to spark, where the extra 5% provides enough extra compression to allow for 91 octane compatibility. The way I see it, that 5% leeway for an 87 tune not only wastes time (in the sense that while the piston moves, it is doing nothing productive) but also is also wasting efficiency due to friction, and even more efficiency by compressing the fuel more than it needs to (which takes energy).

Obviously the Subaru engineers know what they're doing, but I'm just wondering what exactly the point is of having the pistons travel farther than they need to.
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Old 11-21-2017, 10:25 AM   #2290
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Originally Posted by schmidtbag View Post
I've wondered the same thing, but I'm pretty sure when the spark fires is really the only difference. To my understanding, the higher the octane, the more it needs to be compressed before being sparked.

To me, there is an implication that the engine was built with enough room to handle higher-octane fuel. What doesn't make sense to me is if Subaru never intended these engines to use higher compression, wouldn't that mean the distance at which the pistons move is excessive, and therefore wasteful/inefficient?
Hypothetically, let's say that for 87 octane, the piston only needs to stretch out 95% of the way until the mixture is compressed enough to spark, where the extra 5% provides enough extra compression to allow for 91 octane compatibility. The way I see it, that 5% leeway for an 87 tune not only wastes time (in the sense that while the piston moves, it is doing nothing productive) but also is also wasting efficiency due to friction, and even more efficiency by compressing the fuel more than it needs to (which takes energy).

Obviously the Subaru engineers know what they're doing, but I'm just wondering what exactly the point is of having the pistons travel farther than they need to.
Ah yes you are correct.

https://en.m.wikipedia.org/wiki/List_of_Subaru_engines

Looking at the compression ratio of some engines:

FA20F (WRX and Forester XT) which are turbo compression ratio of 10.5:1
268HP

FB20B (Impreza 2012-2016)
compression ratio of 10.5:1
148HP

FB20D (Impreza 2017+)
compression ratio of 12.5:1
150HP

So it looks like physical compression doesn't matter so much and it's all timing. So might I try the 91 octane? Yes. My MPG game really isn't that great anyway. I run around 22-25 with gridlock traffic.

But will the additional (mystery) 1-15 hp really make a difference that I can feel other than my wallet being lighter?

I thought it did, but then again I hated the acceleration ramp up of rev5A's 87 tune.
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Old 11-21-2017, 10:27 AM   #2291
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Been running 5a on 91 for a while and had no issues aside from when I initially flashed the tune in. On start up it would bog out after firing and I would have to give it a minor shot of throttle to get past this bog down RPM. It happened twice and has never been an issue since. For driving I have no complaints on this 91 Rev 5a, the weather has certainly gotten a lot colder here so fuel consumption sucks (winter gas + warm up cycle).
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Old 11-21-2017, 10:33 AM   #2292
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Quote:
Originally Posted by Jimpreza111 View Post
Been running 5a on 91 for a while and had no issues aside from when I initially flashed the tune in. On start up it would bog out after firing and I would have to give it a minor shot of throttle to get past this bog down RPM. It happened twice and has never been an issue since. For driving I have no complaints on this 91 Rev 5a, the weather has certainly gotten a lot colder here so fuel consumption sucks (winter gas + warm up cycle).
Same experience with me
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Old 11-21-2017, 10:47 AM   #2293
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I'm still on like 4a or 4 or some ****. Definitely the last person now. I've already sent th several emails in the past, think I should send one again or just accept I'm not getting any new updates?

Also my car has stumbled especially when it's just slightly warm (the engine not the air temperature) regardless of the tune once in a while. Again, probably that stupid ass emissions stuff.
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Old 11-21-2017, 10:57 AM   #2294
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@Jimpreza111 and Angelus911
Out of curiosity, were these issues you experienced within the first few hundred miles of flashing the tune? I wonder if it was just the ECU still trying to calibrate. Also, what fuel were you using?


Quote:
Originally Posted by Pelco View Post
So it looks like physical compression doesn't matter so much and it's all timing. So might I try the 91 octane? Yes. My MPG game really isn't that great anyway. I run around 22-25 with gridlock traffic.

But will the additional (mystery) 1-15 hp really make a difference that I can feel other than my wallet being lighter?
Yeah now that I really think about it, I don't see why not to try 91. If anything, I would think the 91 tune on 87 fuel would burn more reliably, and perhaps give a little bit extra torque at very low RPMs. I'll probably try the 91 tune in January, after I get my inspection done. I'd like to do it now but I don't want to raise suspicion about how recently the ECU was reset.

As for your fuel economy, that does sound pretty bad, but, I've found these cars are pretty awful with high-traffic fuel economy (at least the manual is). My yearly average is 34MPG but maybe 75% of my drive is a pretty constant speed.
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Old 11-21-2017, 11:33 AM   #2295
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The only place the NA FB engines get respectable MPG is 30-60mph with cruise control. Add a single slowdown even once every few miles and you shave off 5-10mpg. Traffic or actual real world driving will knock it down almost 20 from what you get at ~55 on cruise.
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Old 11-21-2017, 02:27 PM   #2296
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Quote:
Originally Posted by schmidtbag View Post
@Jimpreza111 and Angelus911
Out of curiosity, were these issues you experienced within the first few hundred miles of flashing the tune? I wonder if it was just the ECU still trying to calibrate. Also, what fuel were you using?
Pretty sure my issue was due to having some 87 still in the tank when I filled with 93 and then flashed. Wasn't a big issue.
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Old 11-22-2017, 10:56 AM   #2297
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Quote:
Originally Posted by schmidtbag View Post
@Jimpreza111 and Angelus911
Out of curiosity, were these issues you experienced within the first few hundred miles of flashing the tune? I wonder if it was just the ECU still trying to calibrate. Also, what fuel were you using?
I had been running 91 tune (Rev 3a, never had rev 4) and 91 fuel for months prior to this. I think it was just the ECU learning the new tune. I'm not worried about it though as it hasn't been an issue since the first two days of flashing.
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Old 11-22-2017, 01:08 PM   #2298
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Quote:
Originally Posted by schmidtbag View Post
@Jimpreza111 and Angelus911
Out of curiosity, were these issues you experienced within the first few hundred miles of flashing the tune? I wonder if it was just the ECU still trying to calibrate. Also, what fuel were you using?



Yeah now that I really think about it, I don't see why not to try 91. If anything, I would think the 91 tune on 87 fuel would burn more reliably, and perhaps give a little bit extra torque at very low RPMs. I'll probably try the 91 tune in January, after I get my inspection done. I'd like to do it now but I don't want to raise suspicion about how recently the ECU was reset.

As for your fuel economy, that does sound pretty bad, but, I've found these cars are pretty awful with high-traffic fuel economy (at least the manual is). My yearly average is 34MPG but maybe 75% of my drive is a pretty constant speed.

There may or may not be some confusion as to what is actually happening with the 91 vs 87 tunes, but I'll comment on it anyway just to be clear. The compression isn't that big of a factor, though it does allow for more power, higher efficiency and more effective use of higher octane, hypothetically, with a ton of variables thrown into that statement. In reality, pertaining to our cars, the main difference is the timing. 93 doesn't have to be run at a higher timing, and the timing has nothing to do with the end compression of the air/fuel mixture when producing more power. You can put 93 into an 87 engine and it will run forever, same as 87. The only thing that will go faster is your money. The difference is in the mechanical power extracted from the pistons through the stroke. By delaying the ignition (timing) the piston is at a mechanically advantageous position to extract more power due to the position of the piston/crankshaft which, quite literally, gives it a higher leverage ratio on ignition. With 93 you can delay the ignition longer to reach this superior leverage ratio because it is less likely to detonate prematurely, and the same goes for E85, which produces great power in this car. There is a limit where the effectiveness of increasing octane rating and timing starts to be less relevant, and E85's rating of something like 105-110 octane is really overkill, but the principle is the same (it should be noted that there are a couple of other minor variables that increase the power output of E85 outside of its octane rating).

For the above reasons it's hypothetically inadvisable to run 87 octane on a tune set up for 91 octane due to the risk of premature detonation, which can, over time, cause damage to the engine. Our engine and pretty much all modern engines that aren't abject garbage have pretty effective knock sensors that mitigate this problem to nearly zero, but it's still not really recommendable just to be safe. Basically you can run TH's 91 tune on 87 safely if necessary, but you should generally avoid flooring it or doing this for prolonged periods of time.

In the case of the 91 vs 87 tune relating to our cars, 91 definitely produces more power, demonstrably. The top end is where you gain the most, but through the powerband there is more torque and max HP. Delicious tuning got an extra 12hp out of the wheels on this car with a 91 octane tune, so from this we can extrapolate that TH will probably be able to extract the same or maybe very slightly more. That is an increase of about 12% over the stock wheel HP of ~100, so the crank HP can be extrapolated to be roughly 12-15% higher due to driveline losses. This is of course hypothetical, but the reality is the acceleration will be improved meaningfully, if that's something you're willing to pay for. The efficiency should also be theoretically better, but I never saw a difference between 87 and 91 tunes. I used to run 91 and loved it. I ran E85 for quite a while and the power was fantastic. I now run 87 for financial reasons and don't mind. The tune is so good that the driveability between the three is basically the same, only the actual acceleration rate of change is different.

Hope that helps clear things up.
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Old 11-22-2017, 01:53 PM   #2299
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@Dirt Bringer
That does help clear some things up. I may look deeper into what you wrote later. Not that I'm really ever going to do anything with this information, but I just like understanding how things tick.
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Old 11-24-2017, 11:43 AM   #2300
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Got an Openport 2.0 on order, can't wait to get things rolling on this.
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