Well recently I decided to use some race gas and crank up the boost with my car and take it to the track. The first time I tried it I was running about a 103-104 octane (3 gallons of 93 in the tank already and put in 5 of 112) and was able to get a best of 12.414 @ 110.8. A week later I decided to go down again and try a little less octane but same boost levels as last time which was about 28-29psi spike and holding 24-25psi to redline. This time I had a octane mixture of about 99 and was only able to trap at upper 108mph with basically the same weather conditions as last time I raced. So I went back to the race gas pump and threw in a gallon of 112 which brought me up to about a 101.5-102 octane and I was able to trap upper 109mph now. Now looking at my data I have accumulated here it seems like the more octane the better I run. Im thinking if I should just try straight 116 next time and see what I can pull. I am also tuned for 93 octane at 22psi via TT custom tune. Since I am getting better times with the higher octane levels that means timing is getting pulled due to knock? Should I keep going up in octane levels by about 3 each time until I don’t gain anymore mph in my traps to find my maximum output with race gas? Any input would be appreciated.

 

Why not run c16... u prob have no clue what aire fuel your car runs with the race gas do you? I would say ur car is pulling timing with the lower octane at that boostlevel...

 

thats what i am suspecting but just dont know how much octane is needed. I dont have anyway of checking a/f ratios or knock count but figured sumone should know if your flashed for 93 octane and 22psi, how much octane do you need if u want to spike 29psi and hold like 25psi to redline? There has to be basically a general answer on this, i just dont know what it is.

 

Ya, if you dont know your knock or timing or a/f -- run the highest oct you can get your hands on if you are pushing 29psi out of the stock turbo. Running too low an oct and high boost = knock, retarded timing, and detonation. Which could lead you to a motor with a hole the size of New Jersey in the side of it.


With your mods I was running 12.1x on 93oct @ 22psi. Same mods and straight 100 oct unleaded and 25 peak psi = 11.9x.

 

Well my friend that owns a shop has several 55 gal drums of VP C16 so I can use that if I want…ill pump my tank out and throw in sum 116 and see what happens. I figure ill leave about 1 – 2 gallons of 93 in the tank and throw like 3 gallons of 116 in giving me about a 107-110 octane. If im going to race on race gas once in a while what can I get to monitor my knock, a/f and timing so I can get the most out of the race gas and higher boost? Pocket logger? UTEC? DSM Link? I am not familiar with tuning at all and would want something simple and easy to figure out.

 

EcuScan for knock/timing, Wideband for A/F (unless EcuScan can read that - but I dont have it so...)

 

no one is gonna know cause every car is gonna be at least slightly different and weather conditions is gonna change it too. go get tuned for race gas

 

you really should be running those times & traps on pump gas with 22-24psi, there is no need for race gas and that kind of boost to get those times. I have the same mods as you, less cams, and I go 12.4 @ 110 on pump gas and a 24psi spike setteling down to 21psi @ redline. Something isn't right with your setup...

Its possable your running TOO much boost and just blowing hot air.

 

Bad idea to just turn up the boost without knowing what AFR you are pushing. Save up for a WideBand man.

 

I just noticed you have a custom TT tune. I know a guy with the exact same mods as you including tune who runs 12.4 @ 109 on 91 octain in 100* heat and 100% humidity. As I mentioned before there is something up with your car or how your driving it. I would suggest a boost leak test and a fresh set of plugs to start off.

 

i havent run on 93 octane and 22psi like i am tuned for so i might try that next. I think i just turned the boost up a lil to much and did more harm than good expecially b/c i dont think i had a high enough octane for the boost i was running and was prob blowing hot air. Is there anyway i could get a dual stage flash from TT so i can run a race gas map and pump map for the street? If not what is the easiest/simple, nothing fancy system to use to be able to switch to a race gas map on the fly?

 

I'm sure they can provide you with a race gas map, and you can use ECUFlash w/ a laptop to switch maps on the fly, but honestly adding more power isn't the answer and will only complicate things. You should learn to use the power you currently have before you try upping the boost. THere is something either wrong with your car, your setup, or your driving. I think its a combo of the first two. With your mods & that custom tune you should be running mid 12s at 110 on pump gas and 22psi. Get to that point before you try adding more power.

I'm going to be at Atco this week, if you come down I'll give you some pointers on launching/shifting and we'll see where your at.

 

thanks...but i think im done with the track until next year. Ill race on the 93 and 22psi and see what i do then. I know my launch isnt my weak point cause i pull consistant 1.65-1.68 60ft's and i never miss gears but could prob shift a lil faster, im not looking to beat the crap out of my trans/TC/diff's. stock i ran a 13.6 @ 100 - clutch restrictor removed, mail in flash and no cat 13.0 @103-104 - then the full exhaust, intake, hard pipes, fuel pump, clutch and custom tune 12.4 @ 110.

 

if your pulling 1.6 - 60's then your driving isn't the issue. just try 22psi and 93 octain next time your at the track then and see what happens.

 

I'm pretty new to Evos but I'm guessing that 22psi on 93 octane is near the limit of getting knock. Going up to the 29 spike and holding 24-25psi is probably past the good efficiency point of the stock turbo so you're blowing more hot air than anything and probably getting knock, so the car is pulling timing.

I would just invest the $80 or so for the cable to hook up to the car, and ~$25 for the Evoscan software, and you'll be able to datalog everything. I'd keep an eye on MAF voltage and knock count. With the MAF voltage, you'll be able to see if you're actually sucking in more air (= more power) with the increased boost.

Also, I'd only run unleaded race gas.... lead isn't so good for the O2 sensor! Or cat for that matter.