How hot was it man? Heat is a huge issue, but Iâm not sure itâs a 13.7 issue. I donât even like to run my car if itâs hotter than 70. Was it one of your first visits to the strip? You could lose a lot of time shifting too slow or going out of your power band and wasting time.
thats weird. our car wasnât really fast when you want in the fall when it had full catless exhaust and some lightweight partsâŚI think you were running low 14s @ 98-99 or so, correct? And that was with densit altitude of around 200 feet.
Today you ran 13.7 @ 101 in density altitude that was surely near 2500 feet. So thereâs that.
Still, itâs not as fast as it should be, considering. I donât know why.
Did you see Mistro there in his black RS4? It is bone stock and he was thinking of going today (although I may have convinced him not to since it was so hot and would be busy as fuck).
Basically ou went in perfect conditions to suck. I would go in the fall to get a better idea.
For reference, my RS4 went 12.75 in great density altitude (280 feet) but when I went a few weeks ago for fun it ran 13.30 or so on 91 octane. I basically wanted to see what the worst possible quarter mile time an RS4 could run would beâŚand I wanted to throw in some race gas to see how much it could help. It shaved 3 tenths and added 2 MPH for reference in case anyone cares. I went on a bitching hot, superbusy night (got 3 passes). I had shitty 91 octane in the car. I launched like a fag and bogged it (1.95 every time). Basically a worst case scenario so that when someone runs 13.50 with an exhaust and lightweight wheels on 93 octane, but their timeslip âblows out the windowâ I know how much the driver is hurting things. 13.30 @ 104-105. I should find the slip and make a thread. The 110 octane I threw in to create a mix out to around 100 was basicall good for 13.08-13.15 @ 106.6 or thereabouts.
I mentioned the temps in my initial post. 25c isnât that bad guys. Sure, itâs not great but itâs not awful either.
Also, I was neck and neck with sakiâs RS4 in temps that were 10c hotter. Doesnât make sense.
A 1.9 60ft isnât great either but itâs not plain awful.
As for when I was stock, I couldnât get any traction on the launch that day. I think my tires were over-inflated and the launching section was way more slippery than today. I was doing 2.4 60 footers that day with a 14.1
Again, makes no damn sense.
And no, it wasnât my first time out. Just my first time this season.
still, your MPH is what I was looking at when you were with us last year. It was super low. 98 MPH is like tip Avant MPH, not MT6 catless exhaust Avant MPH in 0 density altitude.
Which leads me to my threadâs title. What could be causing this? I personally feel like the car is running too rich when I start pushing it. But thatâs just meâŚ
Maybe there were still a few coolers hiding in that spacious avant you forgot to take out? 
I didnât up going. I was originally planning to go with Birdman but he slept in and I ended up having to go shopping with my fiance anyways⌠canât argue with her when it comes to shopping lol. Plus as Saki mentioned it was probably going to be more crowded than a Wednesday night anyways.
Was this the run from last time? (14.0 @ 99 mph)
http://youtu.be/vuXShGfjT0c?t=1m42s
The temps today werenât all that bad either. Yesterdayâs rain took out a bunch of the humidity too.
Did you happen to get the runs on your dash cam?
Edit: I should mention that I have H-pipes in there now, but I doubt theyâd make much of a difference anyways since the cats are all still in place; Iâm assuming my driving would probably affect the result more.
Edit 2: What gas and how much in your tank?
Looks like youâve got some logging to do Axel. :-\
I took everything out, including the rear Avant trunk cover
It wasnât too bad. Just those damn 8/9 second cars taking 5 minutes to stage really slows things down. That and they had a motorcycle lapping event which meant a lot of bikes were having fun doing 1/4 miles as well.
That was my benchmark.
Exactly, any hotter and I would have skipped it.
I did, havenât looked at the footage though.
A little less than half a tank of 94 (high octane tune, canât use 91). Not optimal but my benchmark was fully loaded with the same amount of gas so probably about 120 lbs of extra weight overall compared to today.
Even if my driving wasnât far from optimal (I donât go enough to get some good practice in), I wasnât bogging the car and it canât explain a 1 to 1.5 second slower times.
It seems like after a longish highway drive, the car has a little more juice. The more I push it, the slower it gets.
Last time I logged it (a month ago), I was in the 6xx RPMs per second in warmer temps but after some long easy driving.
Back in February (colder temps), I had logged 800 RPMs per second. That said, back in February, I was neck and neck with sakiâs RS4 as well just like 3 weeks ago (both times, easy highway driving before hand).
However, after a bunch of hard pulls with saki a month ago, my CEL came on because my fuel trims exceeded the acceptable range. It went beyond -10% adaptation (i.e. pulling too much fuel back).
My long term fuel trims are all on the rich side but obviously, I donât race the car all the time so the only time I did get a CEL was when I did a lot of hard driving in a short period of time.
Of course, as the car gets hotter and hotter, the system will go richer and richer for safety purposes but Iâm wondering if itâs going too far.
Then again, Iâm no mechanic or tuner so I really have no idea. Iâm pretty much confused at this point.
Neck to Neck with a 12.7 Rs4 and today you ran 13.7. Seriously something to look at. From the sound of it. You said the car was running better on the way home. This to me would say that the blower and the car had some time to cool the oil temps down and to get the car out of what sounds like safe mode.
If you drove all that way and then let the car sit. You basically just let the car heat soak. When you go to the track its good to do a few back to back passes. This allows the car to get air past the oil coolers and obviously help cool the car down
Tell us more on this. What leads you to say this. Is there black smoke coming from the back of the car? Most supercharged apps are going to run MUCH more fuel then your standard NA cars.
Unfortunately, back to back passes arenât really an option. What would you recommend? Simply not shutting the car down while waiting to go back on? That very well might be a big chunk of todayâs problem. The reality is that thereâs going to be a wait before the next run. For the future, what is the recommended method?
When I punch it, there is smoke coming out the back. How much? Hard to tell as thatâs all relative. Letâs just say thereâs enough to see from my rearview mirror but not so much that would cause someone to say âholy crap, thatâs a lot of smokeâ. So a âmildâ amount of black smoke? Iâm also catless if that changes anything.
And as I mentioned above, my long term fuel trims are on the richer side and when I pushed the car hard for a while, I got a CEL for an adaptation number going beyond -10%.
Oh, and I did a quick pull against a JHM tune 4.2L manual converted A6 last week (evening, cooler temps) from about 50 kph to 130 kph and I was only slightly distancing myself from him. Both myself and the A6 driver were surprised. We both expected that I would leave him behind quite a bit.
Iâm not sure that back to back runs to âcoolâ the car down is optimal?? When I go to the trackâŚto run a serious time that I care aboutâŚI arrive early before T&T starts (if your lucky and your gates open early) I park, open my hood, and throw a bag of ice on my IM with a towel wrapped around it so water doesnât run down around the injectors and IM. I only have a 20 minute drive to the strip, but I still think cooling down is a serious factor. After about 30min Iâll go get a pass in to get my adrenaline downâŚlol Usually at our track if you get there early you can get passes in without sitting in the staging lanes for 10-15 min.
I would just wait until it cools down Axel, a lot of people stop going when it gets cooler too, which is even another positive. Good luck though, I hope you figure this crap out.
73-77F temps is not going to cause my car to go from 12.5-12.7 to 13.7.
This is exactly true. When I had my SRT-4 I ran 13.65 @ 103, in 85F temps.
My random thought of the day would lead me to ask how your MAF is looking.
A few months ago it triggered some errors (sensor error). Every time I cleared it it came back 2 weeks later. However, it stopped coming back 6 weeks ago and hasnât come back yet.
Not sure what to do about that one.
I never said it would, but if you want to see good ass times your car being cool is pretty damn important. I think a heat soaked engine and horrible DA could cause a pretty shitty time. Saki just noted that he picked up almost 6 tenths because of shitty conditions. If you think something is wrong you should get JHM on the phone and do some logs, have them look into it from a technical standpoint instead of a thread full of âifsâ and âpossibleâ causes.
yeah, 12.75 @ 108.36 to 13.33 @ 105.5 was the good weather/shit weather gap for meâŚhowever I also had 91 octane in the second time.
Thatâs pretty huge. 6 tenths and 3 MPH.
Now, axelâs car in my mind should have run the following
last fall, great DA, no tune, catless 2.25" exhaust + a couple of LW parts = 13.8 @ 101 (basically stock timeâŚgoing catless with no tune isnât good for much)
it ran 14.1 @ 98-99 so was off a few tenths and a couple of MPH. His launches werenât great so thatâs part of it. Still a bit slow but not drastically.
this week, shit DA, JHM supercharged and lots of bolt ons = 12.80 @ 110
this fall, great DA, same mods = 12.40 @ 113-114
Just my guesses of course on what a car with those modlists should run in those conditions on our track. I think next Detroit meet when jaybquick and count vohn are there, he should bring the car down for them to check out with their own eyes.
AXEL - post your timeslip up so we can get a look at the various times etc. and so I can see exactly when you ran to determine DA.
I think the heat soak played a large part as Carlos mentioned. Will have to go back on a cooler and more importantly, less busy evening. The 14.1 were really crappy launched and not a good indication. I think a 13.9 would have been easily achievable with better traction at launch. Still, I was surprised at the bad times.
I still think thereâs some other smaller issues but not completely sure.
Iâll post the timeslip when I get home later.
As for the JHM guys in Detroit, Iâll be there for sure. Is that usually in the fall?
JHM has my next tune available with LA so weâll see how that works out once I get it.
Iâm trying to explain that the 14.1 even if you launched it terrible still had a trap speed that was around 98 MPH. Your trap speed isnât going to change 4 MPH becuase of a poor launch. The distance of the track and your accelerating power will determine your trap speed, not how well you launch the car (wellâŚit wonât move the needle 4 mph or something on these cars). Provided you shifted gears reasonably well, the trap speed will be within 1.0 MPH of itself 95% of the time for the same car at these power levels.
Look at my runs from AprilâŚI made like 13 passes, including 8 where I wasnât taking it easy or screwing up gear changes. The variance in trap speed was tiny on these runs. Only one of those was more than 1% off the best of the dayâŚand that was 1.7% off.
12.75 @ 108.3, 1.83 60â
12.77 @ 108.2, 1.85 60â
12.79 @ 108.2, 1.85 60â
12.81 @ 107.7, 1.84 60â
12.82 @ 108.0, 1.83 60â (vs. the C63 AMG 13.7 @ 110.6)
12.90 @ 107.2, 1.88 60â (vs. B8 S4 GIAC 91 TUNEâŚhe ran 12.92 @ 109.
12.90 @ 107.4, 1.86 60â
12.97 @ 106.4, 1.87 60â
Sakiâs right about the correlation to trap speed; you are losing some good power. The rich symptoms under load sound like a small boost leak. Losing any of that metered air will make for a rich condition. What is the baseline psi for that kit anyway? A leak at lower pressures is generally easier to find.
edit: what I meant by the last statement was that if you have a leak at lower boost pressures it is generally easier to find than leaks only found at higher pressures. Pressure testers are cheap and effective.