[pelotonracer2]

Without turning this into a debate about the "best gas", I prefer 76 for best resistance to pinging (Nissan did a big study in the 90s and concluded it was the best for this application). I'm sticking to that for now.

fuel formulations have changed a few times over since the 1990s.

 

[pelotonracer2]

Yeah, the problem is that most gas stations these days are "franchises". They only have to purchase fuel from the franchisee refineries for a contracted amount of time and then after that period they can buy fuel from whomever they want (usually the cheapest gasoline they can find). It's one big reason I steer clear from ma and pops gas stations or convenient stores. Even though the sign might say "Shell" or "Chevron" or "Mobil", the fuel they buy is rarely those companies formulations. As absurd as this will sound, I really like "Quick Trip" gasoline. Never had an inconsistent batch of fuel and I usually run very aggressive tunes compared to OTS maps. I think much of it boils down to geographical location as well. Fuel formulations can vary drastically from one region to another. We don't have many (if any) 76 stations in Texas anymore.

 

[pelotonracer2]

Anyways, regarding your original question, I wouldn't recommend running a 93 OTS map on a car running 91. Much of that is centered around boost reduction as rpm increases. The 93 maps have less boost taper/reduction as rpm increases and have higher overboost or mid/high range boost targets. It's that 1-2 psi that usually sends you over into detonation on the slightly less octane fuels. Also, timing curves might also be slightly more aggressive as well. Since this motor has such high compression, I personally would not take a chance.

 

[pelotonracer2]

With that said, I CANNOT wait until Cobb releases the Race Tuner software for this application. I made some really nice tunes (using the stock OTS as a base) for my modified 2011 Mazda MS3.

 

[pelotonracer2]

A racer I know used to pick fuel by Fiat.

Anything that wouldn't ping in his Fiat was good enough for his race car. At a lot of places 91 would still ping, at some places 87 was good enough.

That was a long time ago before race gas was a common thing but it shows how far off the octane numbers can be.

If you ever de-cat your car, you might figure out a way to get low lead 100 from your local municipal airport.

LOL. Whatever works I guess.

 

[pelotonracer2]

I just talked to Randy at FSWERKS about their experience on both of the available maps (91 and 93 octane). To be clear, he only recommends we run the 91 octane program. He went on to say that for a variety of reasons, the 93 octane map isn't very happy in regions that have 93 octane fuel available, presently. Whether this has to do with a winter blend of fuel or other changes in the way the fuel is being refined, it's clear that the 93 octane map isn't making lots of people happy right now (suggesting that fuel quality is to blame, and possibly not being a true 93 octane). How are people here doing with the 93 octane map?

On the other hand, both maps will simply run better with higher octane fuel (of course!). Randy mentioned that we have another 5 degrees of spark advancement or so available that can happen dynamically. His final recommendation was that if you can get "an honest blend of 96 or 97 octane", you could safely run the 93 octane map and get bigger gains. I may do some mixing and see what happens. Again, getting race fuel isn't that convenient for me right now.

Randy closed with a comment that their Fiesta ST efforts are underway, but we won't see anything product-wise until early next year.

I hope by "early" he means sometime in January... hehehe

 

[pelotonracer2]

Again, getting race fuel isn't that convenient for me right now.

Yeah, me neither. I used to buy 55 gallon drums of 103 octane unleaded for our motorsport program. I don't even know where to get it these days.

 

[pelotonracer2]

the 'answer' to 'race gas' is e85. Assuming the fuel system can deliver or that it can be modified to deliver. i run it in my WRX and get 300 whp from a 2.0L.

I used to have a modified 240z running a 280z motor with a custom turbo setup and adjustable boost. i could run regular and turn the boost down or run race gas and turn it up past 25psi. this was in the 90s and i was paying 5 or 6 bucks a gallon then and it was drinking the stuff. nowadays race gas can be as much as 20 bucks a gallon. e85 is as good as medium grade race gas (105 to 110 octane) and cost about as much to run as high test (not as expensive but it takes more).

and you can get 100 octane no-lead race gas. i used to run it in my sportbikes during track days.

if possible, a slightly larger turbo, bigger intercooler, big cat down pipe, bigger turbo back exhaust, e85 tune would be nice.

i await cobb's access tuner race, and turbo back exhaust before i buy. this is what i run on my WRX. you could take their '93 octane' map and tweak it a bit if its a bit too aggressive for you local 93 gas.

Yeah, I don't think we can get E85 in Texas. I will try my regular old 93 octane premium with the 93 tune and pay special attention to ping. I had no issues running local 93 octane with my MS3 set to overboost peak of 19.5 psi, with taper to 17-18 psi (which is considerably more than stock (15.5 psi). Never any problems with deto on that vehicle. I will get the access race software the same day it is released. lol.

 

[pelotonracer2]

Thanks for this. When I was tuning my 370Z, I ran into a few guys doing the E85 routine (over at Sean Church's place).

Anyhow, E85 takes some consideration. I don't know if our fuel system is E85 ready -- is our car a "flex fuel" car? If not, that's something to sort out.

100 octane no-lead is available, but just not convenient. Back in 90s and early 2000s, I could get it from my local 76 in a pump. I recall thinking how expensive $4.50 a gallon was! I'd kill for that price now.

I really don't want a bigger turbo right now. I think part of the fun is the super fast spooling -- but I totally get that we can install a bigger turbo with superior characteristics (spool, flow, etc.). The turbo-back exhaust and down-pipe (and big cat) is good stuff and I'll probably do that.

Also, I had two WRX cars! I love them. If my dealer had a "base" STi, I might be driving that now (great deals on those right now). I had an early Cobb tune on my "265HP WRX" and it was good fun. My early 2001 WRX was more built, but frankly didn't make big power (I ran a lot of the AUS rally scene stuff).

This is a great conversation, and I'm looking forward to more on this topic. I hear that E85 is a lot easier to find, so that could be a real alternative.

Trey Cobb personally built my '02 RT-Spec WRX when they were here in Texas. I sometimes wonder what the Fiesta ST would be like with AWD. lol

 

[pelotonracer2]

What is funny is nearly each time the gauge will display a max boost pressure of 649psi. Clearly off by a few pounds. Here is where I have mine mounted

Yeah, clearly. lol

 

[pelotonracer2]

^^^ That's actually a GREAT place to have the Cobb AP. Can you see the screen without interference from the steering wheel? Thanks for posting pics.

 

[pelotonracer2]

@#$% UPS is late delivering my Cobb AP this morning.

 

[pelotonracer2]

I'm guessing we're going to get more of this kind of feedback on the 93 octane map. Randy basically said the same thing about the car losing a step or two. I'm very curious how it runs with the 91 octane map on the same "93 octane" fuel. Even without the explicit parameter changes in the 93 map, you'll gain some spark advance, and will better off than us poor CA folk.

Since you are running multiple tuned turbo cars, can you confidently say you don't have a local fuel problem? It would be nice to get to the bottom of this.

Yes I am fairly confident in the quality and consistency of the gasoline that I buy but I will also always be cautious with this platform initially. To be honest, I have seen a degradation in performance on CA fuel compared to what we get here. My Mom lives in Carmel, CA and the couple times I drove there from Texas, I did notice a significant difference in performance but some of that could be air quality issues. I always thought it was some CARB specific blend difference. I will try both maps and see what differences I feel and can see with the different gauges on the AP.