Tuning Guru's please explain

[ikle]

Today I had the opportunity to do some third gear pulls to 5,000 rpm, since I have gotten my PowerLogger up and running, and to my surprise I am able to run 20-21 lbs of boost with no knock and WBO2 11.2 on 93oct fuel only. How is this possible ? With all the reading I do I should be only able to run 16-18 lbs of boost with 93oct. I did 3 pulls and the first one was a bit lean WBO2 12.4 and had a little knock of 1.4, but quickly went away, so I added some fuel to 148= 15.6% on my TT 93oct street chip. The second pull WBO2 was 11.2, with no knock, so was the third. I verified the boost with my boost gauge and it jives with the PowerLogger. So can anyone explain this to me how this is possible ? Thanks for your help, Kyle.

 

[TT/Ameasap]

What was the narrow band reading and where is you WB located?

 

[ikle]

What was the narrow band reading and where is you WB located?

WB located about 1 foot from the end of the DP right after the second bend at the firewall and narrow band was between high 770,s to low 790,s. Thanks for your reply, Kyle.

 

[TT/Ameasap]

What is your timing showing?

 

[ikle]

One thing I did notice when I went to the configuration page in the PowerLogger that the MAF setting was at 512 ( extender chips ) not 255 (standard) like it should be. Thanks again, Kyle.

 

[ikle]

What is your timing showing?

Timing 18.0 degrees

 

[earlbrown]

It just goes to show there are no magic numbers.

 

[ikle]

stupid question, how do I upload the log after it is compressed so you guys can take a look ?

 

[Pronto]

Bottom of the reply area is a radio button "upload a file". Select it and upload it.

 

[earlbrown]

and don't forget to mention what chip you have and what wideband.

 

[ikle]

Bottom of the reply area is a radio button "upload a file". Select it and upload it.

I tried that and when I select the file it says " There's been an error uploading file " Thanks, Kyle.

 

[Amelio]

As Earl said there are no "magic" numbers I have had my hands on several different cars and I have learned all cars are different. There is some what of a standard window but its not across the board.

Depending on the air temps I have seen 20psi in my car with no knock on pump gas.....this is not a tuned number but rather a boost spike due to cooler temps. I usually tune to 17psi on 93oct but the car has seen 20psi with zero knock.

Either way if you are hitting that boost and there are no issues I would not bang my head against the wall to try and figure out why.....the car just works there.....enjoy it

 

[TT/Ameasap]

Yes, all of these cars are different, But I can tell you something is strange because 20-21psi is a lot of boost for 93 octane. That limit should be around 18-19 with an excellent tune for it... and thats on the high side. of course there are people that claim that they could run more on 93 oct. but I have had 5 of these cars and not one could run near that without knocking. The old reds chips used to drown the car out with fuel, but it had its limits. Hacked 50#Thrasher chip was the only chip I could run 18psi on with 93 octane. That was with an excellent tune and power plate.
Post up a PL file

 

[we4Mateo]

Yes, all of these cars are different, But I can tell you something is strange because 20-21psi is a lot of boost for 93 octane. That limit should be around 18-19 with an excellent tune for it... and thats on the high side. of course there are people that claim that they could run more on 93 oct. but I have had 5 of these cars and not one could run near that without knocking. The old reds chips used to drown the car out with fuel, but it had its limits. Hacked 50#Thrasher chip was the only chip I could run 18psi on with 93 octane. That was with an excellent tune and power plate.
Post up a PL file

I think the 18* timing is key. I've been 20psi on pump 91 swill but with even less timing than that.

 

[TT/Ameasap]

18° is the norm for a street tune. Most of the chips I have played with were street tunes from Eric,Red, Lubrant, and a few others.
It could be that one tank of gas or just that pump too. I would keep an eye out on the next fill up for sure.

 

[Pronto]

My first chip upgrade was a Thrasher chip. It was for 36lb injectors and 93 octane street chip. It would let 1st gear go to 21lbs. Never saw knock. Went high 12s with that chip. Don't know what timing it had.

 

[robzombie]

I have run 22/23lbs. on 93/no alky with my BB/EE chip with 23/21 timing all the time.

My wide band is in the 11.2/11.5 range normally but will get slight KR if it goes any higher and even when at 11.5 once in awhile depending on temps both on the car and air.

I know some don't agree with running that much boost w/out alky but like mentioned by others, every car is different and should be tuned as such.

What some may not realize is that we are supposedly getting a minimum of 93 oct. and or up to ten percent ethanol which can vary octane and cooling effect depending on the mixture.

That is the reason I buy my fuel at the same station every time and so far have had repeatable results every time. When you buy super unleaded it's in it's own tank and 87 is in it's own tank.

When people buy mid grade all they are getting is regular and super that is metered by a mixing valve in the pump which can also affect the real octane number that is received.

Different additives in the fuel may also play a small role in how the fuel burns in our engines under boost.

I guess what I'm trying to say is that there are many variables that come into play that some people don't even take into account.

 

[earlbrown]

Keep in mind.... when he's seeing 20PSI on the boost gauge, that doesn't mean there's actually 20PSI.


The number is just that... an arbitrary number. The gauges we used aren't calibrated by the National Institutes of Standards and Technology. That same gauge might still read 20 if hooked to a car running 17.

VDO could start selling boost gauges with a cow, a chicken and a naked trucker chick on it, and it would work the same. Tune for maximum trucker chick then drive it until the gauge alerts you to something odd. Like only being able to get to cow at WOT indicating a re-cracked DS header.


Boost is just air that the engine CAN'T swallow. Not a direct indication of cylinder pressure .vs knock resistance.

 

[robzombie]

Keep in mind.... when he's seeing 20PSI on the boost gauge, that doesn't mean there's actually 20PSI.


The number is just that... an arbitrary number. The gauges we used aren't calibrated by the National Institutes of Standards and Technology. That same gauge might still read 20 if hooked to a car running 17.

VDO could start selling boost gauges with a cow, a chicken and a naked trucker chick on it, and it would work the same. Tune for maximum trucker chick then drive it until the gauge alerts you to something odd. Like only being able to get to cow at WOT indicating a re-cracked DS header.


Boost is just air that the engine CAN'T swallow. Not a direct indication of cylinder pressure .vs knock resistance.

Octane is just an arbitrary number also. If you think some stations aren't scalping somewhere you're kidding yourself.

I use the same station all the time so I can attain NAKED TRUCKER CHICK on a continuous basis.

Keep in mind.... when he's seeing 20PSI on the boost gauge, that doesn't mean there's actually 20PSI.

Well I've hooked my boost gauge up to my butt and saw 22 lbs.of booooost but I was on alky if that makes a difference.

If my gauge is inaccurate what do you think the actual poundage coming out of my butt was???

 

[Pronto]

You wouldn't want to see the trucker chicks naked that are at the truck stop up the road from my work.