Jspazz said this in another thread but to be honest, I just don’t see it.
Looks like maybe two tenths and two mph difference for the most part. The NA cars (RS4 etc) see similar results.
What am I missing?
I haven’t seen much comparing 93 vs 100 but the little I’ve seen I’d say at our mod/power level its good for 4+ tenths.
Not a lot of V8 guys even attempt to run race gas because that’s now how we did things a couple years ago. Running a 12.9 in a B6 on race gas means jack, unless you run it all the time. I think B8 guys really started the whole race gas thing
81 On your car your best on 93 is what…12.05…and on race it was 11.96. Less than one tenth and less than one mph
So where do you get 4 tenths out of that?
Jspazz was a bit over three tenths and three mph.
B5 loves race
I got maybe 3-5 passes on the 100 tune in 35-45 mins with a bunch of wheel spin causing the damn 1-2 shift delay. My traps where 117+ and where climbing. I’m positive that there is a calibration period where the ecu’s tune and the cars senors need to sort things out before the car begins to run at its potential. The point I don’t know is how long it takes before the tune is fully calibrated?
Kavan, the AZ member who also was there, was only able to hit 12.4+ on 94 octane but after about 3hrs and 10-15 passes 12.0x. Much closer to Jspazz’s experience than mine.
Anyway, I’ll be running straight race gas next week and we’ll see how much, if any, time I’ll pickup.
You would think B5s ran race gas from the factory…and meth
So what’s the typical improvement for the NA 4.2 on 100 octane?
There hasn’t’ been much proven with the S4 4.2l BHF like Joe said.
nobody much cares lol
but back on topic, a few of us have seen 2 tenths/2 mph delta.
jnaut ran 12.84 @ 107 on pump when he was stock
jnaut then ran 12.26 @ 112 on race with stock tune and catless stock size 2.5" downpipes, stock catback, LWFW, LWRx4, LW seats.
Not sure what he’d run with that modlist on pump gas, but I’d be surprised if it was anything better than 12.50@109.5…so I would guestimate that the race fuel helped him to the tune of 2.5 tenths and 2.5 MPH in that case. Maybe a hair more.
I just think it’s another one of these ‘forum myths’ that gets thrown around far too much. Similar to ‘NA cars don’t have much tuning potential’. That’s the catchphrase among the guys who know nothing about NA cars, but the people who know NA cars, specificaly these 4.2 Audis, know we are seeing 5-10 car lengths and 5-10 MPH with tuning and exhaust mods. To say they don’t respond is absurd…and when you look at the gains in the bigger displacement engines (like the 6.2 MB AMG, or the LSX engines where they pickup 100 hp with tune+exhaust) you realise this is complete fucking bunk.
They are somewhat infuriating hearing these maxims floated as if they’re proven facts…when in reality, they’re often nowhere near the truth. The race gas reality is that it’s a difference (not a massive one) on the 3.0T cars, and is also a reasonable difference on the NA cars.
The v8 doesn’t really react to anything higher than 98 octane either. To run race gas with a JHM tune you have to add the gas, then reset the ECU and go out for a 20 minute hard drive to establish a map that makes power with the 98. Get some Toluene and experiment with it. Saki’s S4 pulled almost no timing on 94 in cold weather. My car always pulled 2-3 even in cold weather on 93.
Cheers to people running toluene! Glad I’m not the only fan.
The biggest thing I know is, it’s a difference I can feel in my backside. Especially doing the ATCO runs from the slips above, compared to running 100 octane all Saturday, it felt like something was wrong with the car the next day, running 93 tune, 93 gas. The ability of the car to spin the tires to warm them up was mostly gone, too. I ran that 12.4, then a 12.6, then we decided to leave.
Looking at the logs from Prime’s car, APR throws a LOT more timing in the midrange on the 100 octane file, but then keep it reasonable up top, apparently they claim MBT is limiting them and the car won’t make any more power up top with more timing. I’d bet it’s worth 30-40 horsepower at 5000 rpm.
…which still isn’t ‘massive’ and is certainly not a ‘massive difference’ to the NA cars like the RS4 4.2 FSI (and I imagine the RS5 as well)
It’s a lot more than you can make from intake and exhaust on this platform. And it’s relatively cheap and doesn’t require as much commitment, as say, nitrous oxide. Consider each 10 hp one tenth and 1 mph.
Funny how REVO went so far beyond the ignition MBT on race gas that the tune actually ends up slower. I still haven’t heard about them fixing that.
a revo tune with too much timing advance, I am thoroughly surprised!.. lol 
That’s what happened with the 4.2 tuners who thought they’d just fire a bunch of timing at the V8 to make power. Doesn’t work.
I realise it’s a bump vs. doing nothing, but the point of the thread is that it’s not a massive bump, and it’s certainly not massively different to what the NA cars realise. The delta from stock to race gas is not what we’re discussing. We’re discussing the delta between pump and race on the B8 vs. pump and race on a 4.2
To me a massive bump is seeing a 6-7 MPH gain in trap speed…or as many tenths. That’s massive. That’s something the NA cars just can’t do from octane alone. That’s what the strongest tune vs. stock (pump vs. pump) delivers on the B8. That’s what APR + pulley delivers on the B8 vs stock (pump vs pump). That’s what JHM tune/exhaust delivers on the 4.2 cars vs stock (pump vs. pump). That’s massive…that’s a car-changer difference. That’s 7 car lengths by the end of the quarter mile. That’s the delta that will produce a gap of about 3-4 car lengths in a highway race from 50 mph. That’s getting walked.
2 MPH or 3 MPH…it’s certainly nicem but not the same though.
…0.357 sec and 3.86 mph…that’s a bit harder to do, the faster you go.
e.g. it takes less power to make your RS4 go from 13.2@104 to 12.8@108 than it takes to make a Stage II B8 S4 go from from 12.4@111 to 12.0@115. But wait, it’s easy…I just pour in race gas…
APRs newly released tune for the RS5 shows only a 3 ft-lb and 5 whp gain when tuned for 100. I know that seems a little low, but whatever.
If a stage III ever gets released, and we can start charging more pressure into the 3.0T, gains on race gas will be a lot bigger. I mean, even with the B5, someone running stage I with 17 psig will never see the same gains on race gas as someone running K099s at 29 psig.
Depending what comes out for a blower and/or pulley for stage III, they’d likely even dial down the boost unless you’re running race gas - I can’t see the point of pushing 24 psig into a stock motor if you’d have to run only 5 degrees of timing advance and a 10:1 AFR to cool it down.
Let’s remember the topic…you said the gains from race vs. pump on the B8 are ‘massive’. Yes, you said ‘massive’. You also said the 4.2 cars gains are ‘nothing like’ the 3.0T car gains when race gas is used. That’s just not true as we’ve discussed. When we look at your absolute best case, you are clinging to fractions of a MPH for posterity to push you to a ‘massive’ 3.86 mph.
re: your latest post (which again ignores the facts posted earlier in the thread and talks about other irrelevant shit)…it is riddled with holes.
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where did I talk about my RS4 going from 13.2 to 12.8? Or any RS4? Did you forget already that an RS4 went 12.2 @ 113 on race gas…with no tune? Just decatted and a few lw parts (125 lbs)? And he went 12.84 @ 107 when he was stock? I guess that was his lightweight rotors that got him to 12.2 since the RS4 doesn’t make gains on race gas according to you. :
Or is the gap in performance going to 12.26 light years apart from the gap your car had going to 12.08? Guess I missed that part where (not even) 2 tenths changes physics and bends space. -
You claim ‘it’s easy’… but it’s not. Who wants performance that requires stopping, finding race fuel, then loading some in, then hoping you have enough race to offset the pump gas that was ASSUREDLY in your tank before you decided to add in race gas (since that’s what people have in their tank) so that you don’t knock your engine to death since you’re running enough timing to grenade your motor on a poor mix. Sounds great. If you’re lined up at the stoplight and your buddy beside you wants to race, what do you do…tell him you need to go home first and get your race gas? lol that will go over well. can you say laughing stock? If you’ve got more than 1/4 tank of 91 or 94 in there, you’ll need him to follow you around for a few hundred kms so you can burn off enough to keep your mix adequate to not send a rod through your block.
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When…the fuck…did ANYONE ever gauge performance gains on a 4.2 car by
a) what a dyno says
b) what APR does?
I know you drive a B8 where guys live and die by the dyno to tell them what is fast and what isn’t…and where you think APR can do no wrong. I also know you’re in the dark on the 4.2 MPI and FSI cars…but do some homework man. Anyway, APR haven’t done a thing in 4.2 tuning. Nothing. No fast APR cars on the S4 list…no fast APR cars on the RS4 list (other than the supercharger kit, which they needed some tuning help with before it got going). Let’s see how many APR 4.2 cars on the 4.2 list. oops. 2 out of 40. There’s 1 NA S4 that is in like 20th place…and the one SC RS4 that as I mentioned above needed a little help from a competitor to get over the hump (after running high frigging 12s with the blower on the original APR RS4 SC tune).
www.audirevolution.net/quartermile
- if if if. Let’s focus on what’s actually happening.
oh…not to mention the cost of race gas. If someone will say ‘I run race gas all the time’, let’s look at that.
What’s the premium to run race gas? Let’s pretend it’s only a 50% premium (I think it’s more).
Average drivers do about 12,000 miles/year. That’s about 60,000 miles in 5 years of owning the car. 60,000 miles on these 3.0T cars = about 3100 gallons of fuel, assuming fuelly averages of about 19 MPG. So…with race gas costing an extra $2.25/gallon or so, we’re looking at about $7,000 extra for the privilege of being race gas fast all the time.
Add in your tune ($1500), your pulley ($500), pretending that labour is free, and you’re at about $9,000 in ‘mods’ to run low 12s.
That’s going to be the cost of a base AMD TVSr1900 supercharger kit for the B7 RS4 or a JHM Vortech Cfuge kit. No race gas required on those cars…they’re fast on 91.