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IS20 87octane JB4 or APR?

MeltedSolid

Autocross Newbie
Location
San Francisco Bay Area
Car(s)
'15 Golf, e36 328i
I don’t think a turbo and a tune is going to net you 100HP... certainly not on 87.

Arent... you doing that right now?... not 87, but still?...
 

joofcorn

Ready to race!
Location
IL
golfwang is pretty on point. one thing to consider also, is if you run 87, you can add a couple gallons of e85 per fill if you are really trying to be economical and safe. e85 has a much higher octance, and our cars are built to handle up to 30% ethanol without issue. e85 where i'm at is cheaper even than 87, so adding a bit of it will spike your octane, help reduce chances of pre ignition, and save some cash.
 

joofcorn

Ready to race!
Location
IL
to add one point though, i do not recommend using 87 + e85 as an excuse to get a 91 or 93 tune. While you could technically do this, its not a safe way to go as e85 varies on octane rating (can be as low as 94, or up to 105), and you will need to make sure to put enough in to boost fuel all the way past 91-93. So if the batch you are putting in is 94-96 range, you would need way more than the safe amount for our cars. I only recommend using a bit of e85 to give you some more wiggle room on pre ignition conditions using the 87 on an 87 tune.
 

PLF8593

Drag Race Newbie
Location
Philly
Car(s)
19 Alltrack 6MT
to add one point though, i do not recommend using 87 + e85 as an excuse to get a 91 or 93 tune. While you could technically do this, its not a safe way to go as e85 varies on octane rating (can be as low as 94, or up to 105), and you will need to make sure to put enough in to boost fuel all the way past 91-93. So if the batch you are putting in is 94-96 range, you would need way more than the safe amount for our cars. I only recommend using a bit of e85 to give you some more wiggle room on pre ignition conditions using the 87 on an 87 tune.

This guy makes a very good point.
 

Bäsemödel

Go Kart Champion
Location
Lancaster PA
Arent... you doing that right now?... not 87, but still?...

I did just finish this yes... I’m using JB4 not a full tune though... perhaps this was incorrectly informing my assumptions about gains...
 

MeltedSolid

Autocross Newbie
Location
San Francisco Bay Area
Car(s)
'15 Golf, e36 328i
A tune alone will typically have a slight advantage on a JB4 alone. The JB4 really only gains the advantage when adding e85/methanol/other stuff.
 

sprinks

Drag Racing Champion
Location
United States
to add one point though, i do not recommend using 87 + e85 as an excuse to get a 91 or 93 tune. While you could technically do this, its not a safe way to go as e85 varies on octane rating (can be as low as 94, or up to 105), and you will need to make sure to put enough in to boost fuel all the way past 91-93. So if the batch you are putting in is 94-96 range, you would need way more than the safe amount for our cars. I only recommend using a bit of e85 to give you some more wiggle room on pre ignition conditions using the 87 on an 87 tune.

Agreed that ethanol dosing is NOT the safe way to get past 87 octane. Looking at some literature on LSPI, there's evidence that suggests e20-e30 blends are critically NOT the solution for prevention. In fact, quite the opposite, suggesting these blends result in more LSPI events while NOT mitigating mega-knock (the engine killer) when compared to higher or lower blends.

reference: https://www.thefreelibrary.com/Infl...s+on+Low+Speed+Pre-Ignition+in...-a0528616644
 

odessa.filez

Autocross Newbie
Location
Roswell, GA
Car(s)
2016 GSW 1.8tsi auto
okay so I read several claims here about LSPI and octane. Can you please back them up with authority?

can anyone point to evidence that APR's 87 tune is riskier than say, the stock tune on a 1.8t?

Most of what I've found so far seems to point to oil.

I get the idea that some prefer to be cautious given the possible severity of loss.

But given all this hand wringing, why would anyone tune on any octane level?
 

joofcorn

Ready to race!
Location
IL
Agreed that ethanol dosing is NOT the safe way to get past 87 octane. Looking at some literature on LSPI, there's evidence that suggests e20-e30 blends are critically NOT the solution for prevention. In fact, quite the opposite, suggesting these blends result in more LSPI events while NOT mitigating mega-knock (the engine killer) when compared to higher or lower blends.

reference: https://www.thefreelibrary.com/Infl...s+on+Low+Speed+Pre-Ignition+in...-a0528616644


This is an interesting read, but I'm not sure how much it really means for our cars. I noticed one crucial thing which may make this not apply in many cases, they are running a FIXED timing at -3 degrees, which is after top dead center (very VERY late). Typically, car never reaches negative timing (due to increased chance of pre ignition), and timing is adjusted continuously to advance further as it revs up (mine will rise from 0-12ish). Our cars also have many sensors that are constantly keeping an eye on engine conditions, and will pull timing if it recognizes conditions that could lead to pre ignition. On cars that are pushing the limits of boost and power, adding a bit of E85 is well documented to correct those timing pull events.

What this test seems to be showing me, is that under high load, and a late spark, pre ignition events are more likely in their test setup, and this could be due to the ethanol. This however is not a normal operating condition
 

joofcorn

Ready to race!
Location
IL
okay so I read several claims here about LSPI and octane. Can you please back them up with authority?

can anyone point to evidence that APR's 87 tune is riskier than say, the stock tune on a 1.8t?

Most of what I've found so far seems to point to oil.

I get the idea that some prefer to be cautious given the possible severity of loss.

But given all this hand wringing, why would anyone tune on any octane level?

APR 87 tune is certainly riskier than stock cars. Its running more boost, which means higher compression ratios, and can increase likely hood of pre ignition or knock. No one here was really suggesting that its a liability, it was more of a comment that APR a) is in it to make money, and advertising more power will entice people, and b) that the 87 tune may not be as safe. APRs main business is tuning for 91 fuels and up, and that is where most of their research and time goes. The 87 tune likely did not get the attention that other fuels did, and may have just been released as an option while running 1psi less without doing as much testing. I have not seen what Arin said about the 87 tune, but if is true that he says he wouldn't run it, that is pretty telling since it is coming from an APR employee.
 

odessa.filez

Autocross Newbie
Location
Roswell, GA
Car(s)
2016 GSW 1.8tsi auto
well thanks and no worries.
but do we really know why Arin would say that? maybe he just likes more power. :)
For some reason they were willing to wrap that tune with a warramty. Doesn't prove anything, maybe the fee makes it work and just an irony.
I wonder what the difference in risk is, between an 87 tune generating less power and torque va a 93 tune generating more power and torque.
APR 87 tune is certainly riskier than stock cars. Its running more boost, which means higher compression ratios, and can increase likely hood of pre ignition or knock. No one here was really suggesting that its a liability, it was more of a comment that APR a) is in it to make money, and advertising more power will entice people, and b) that the 87 tune may not be as safe. APRs main business is tuning for 91 fuels and up, and that is where most of their research and time goes. The 87 tune likely did not get the attention that other fuels did, and may have just been released as an option while running 1psi less without doing as much testing. I have not seen what Arin said about the 87 tune, but if is true that he says he wouldn't run it, that is pretty telling since it is coming from an APR employee.
 

MeltedSolid

Autocross Newbie
Location
San Francisco Bay Area
Car(s)
'15 Golf, e36 328i
Sorry to play the complete devil's advocate, but APR plus uses their 87 octane tune, and they're still expecting you to use 87 with that. If they weren't confident in the safety of that tune, why are they willing to warranty it? It's not the IS20 tune, but still, it's the same process to tune a car for any octane, be it 80 or 110 so I wouldn't be worried about the safety of a particular tune based on what octane it's supposed to be rated for. The only thing I'd really be worried about is the quality of the 87 octane fuel itself, but just don't go to a sketchy gas station.
 

PLF8593

Drag Race Newbie
Location
Philly
Car(s)
19 Alltrack 6MT
Sorry to play the complete devil's advocate, but APR plus uses their 87 octane tune, and they're still expecting you to use 87 with that. If they weren't confident in the safety of that tune, why are they willing to warranty it? It's not the IS20 tune, but still, it's the same process to tune a car for any octane, be it 80 or 110 so I wouldn't be worried about the safety of a particular tune based on what octane it's supposed to be rated for. The only thing I'd really be worried about is the quality of the 87 octane fuel itself, but just don't go to a sketchy gas station.

This is a very good point. And I'd note that the APR+ tune for the IS12 1.8's is about the same power output as the IS20 2.0's stock. Since the IS20 cars are also tuned for regular, maybe it truly is not an issue. But the IS12+1.8 has to push more boost to make the same amount of power as an IS20+2.0, so it's definitely still a higher risk.

but you are correct, APR would run the numbers and make an informed business decision about the 87 octane tune before slapping a warranty on it lol
 

Crud_muffin

Ready to race!
Location
US
Car(s)
e-Golf
I ran the APR Plus 1.8T on 87, which it's rated for. Just bought a Facelift GSW and dealer filled me up with it and I tuned immediately. I had the impression driving that timing was low and boost higher than stock. No apparent driveability issues like knock. Now with 91 regular fill ups, there's more ease/less struggle getting to speed and the ceiling is higher. Feels like a stock GTI.

My thing is I'll run 91 always in the event of a batch of bad gas. That way the 87 ECU mapping is there as a safety net. I used to be big time concerned about LSPI on my tuned 2.0L GTI, and much more so now with increased cylinder pressure in the 1.8L. Which is another peace of mind thing with running higher octane gas.

As many know, APR's warranty does 'highly recommend' 91 or 93 even if not the minimum required. And 5k oil changes are mandatory to keep their coverage.
 
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