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05-06-2012, 02:10 PM | #1 |
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Dissapointed in 1/4 results
Went to Baytown drag strip outside of Houston, TX on Friday night for some 1/4 mile runs. There was a huge line, so I only had the patience for one run especially after the poor results. My mods are as follows:
-VRSF Downpipe -DCI -ETS Intercooler -Cobb Stage 2 +, v401 Car is a 2008 135i, 6spd, with around 45k miles. The timeslip is as follows: RT: 1.056 (was more concerned with a good 60') 60': 2.169 330: 5.710 1/8: 8.675, 85.17 MPH 1000: 11.205 ET: 13.356 MPH: 104.08 I was hoping for mid-low 12's at 115. I replaced my spark plugs after going to stage 2+, and I'm on newer RFT's. What are your suggestions? I acknowledge that I'm not a pro driver, but this time sucks, and my shifting etc. was spot on. JG |
05-06-2012, 02:24 PM | #2 |
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More seat time. Keep trying. You should be able to get the 60' time down to 2.0 or lower even with the run flat tires.
Are you turning of DTC completely? When are you shifting? Did you notice power loss after your 2-3 and 3-4 shift? I suspect you are shifting too high or shifting too hard.
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05-06-2012, 02:57 PM | #3 |
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There is definitely something wrong going on after the 1/8th mile as you only gained 19mph in the backhalf. I know firsthand what waiting in line for a long time will do to your intake air temperatures and drastically reduce your performance, however I would say there were other factors hindering your performance. Have you done a boost leak test?
Here is my Cobb Stage 2+ slip with similar mods minus DCI in a different track (4037): |
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05-06-2012, 05:05 PM | #5 | |
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Where should I start my troubleshooting? I haven't gotten any codes except a misfire (fixed with new plugs) and low fuel level (flooring it around a corner with ~5 miles showing - code went away right after I filled up). Jon |
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05-06-2012, 05:06 PM | #6 | |
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05-06-2012, 05:10 PM | #7 | |
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05-06-2012, 05:16 PM | #8 |
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A few things come to mind. With the RFTs you're going to have trouble launching. I don't know how often you practice, but I know I never go to the drag strip or anything, but when I finally am able to launch the car right it really really helps. The RFTs cannot possibly be helping.
Number two, considering you don't seem to be gaining much speed is that you could have your system all clogged up with carbon deposits. Has the car been idling rough at all, or has your fuel economy gone down recently? My car is at 55K, a 2008 model and I'm the original owner, and I literally feel a difference in power (not a huge one, but still some cars have it worse than others) than a year ago with the JB4, or several years ago when with stock boost. Carbon deposits gunking up the engine could be making your car slow. I know some Audi turbo engines can lose as much as 50 horses (maybe more) by 50K miles! Finally, as was mentioned, there could be a boost leak. You can do a boost leak test yourself with $10-20 worth of stuff from a hardware store. Or you can get charged a lot of money to have it done by someone else. If you just google boost leak test there are a lot of youtube videos which detail the process. Good luck, and let us know the results!
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05-06-2012, 05:34 PM | #9 |
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The launch is not the issue as it was slightly better than RmnEvo's. I have been thinking about the carbon buildup for a while - my MPG has gotten worse recently.
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05-06-2012, 06:32 PM | #11 |
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Yeah seems your car is down on power, only trapping 104mph seems way low. Decent 60ft, any idea what kind of boost your car is making? Definitely log the thing and find out what it is doing.
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05-07-2012, 04:23 PM | #12 |
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COBB said the logs looked alright less a potential knock up high which looks to be related to shifting (i.e. the shift is making the knock sensor register). They asked me to re-log on Sport map for a 3rd gear pull. They also agreed that the MPH seemed very low.
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05-07-2012, 10:09 PM | #13 |
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I datalogged again tonight on both Sport and Aggressive v401 Maps and sent them to Cobb for review.
I am experiencing a strange oscillation sound that goes something like "woam, woam, woam, woam" (best impersonation), under hard acceleration. |
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05-08-2012, 01:07 AM | #14 |
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1) Don't worry about reaction time, because that has nothing to do with E.T.
2) Do the boost leak test. Maybe run it on the stock map, if you can and see what happens when you go WOT. |
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05-08-2012, 01:25 AM | #15 |
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I have this oscillation sound as well. I'm running the release Stage 2+ aggressive map.
Last edited by SSSnakeman; 05-08-2012 at 01:30 AM.. |
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05-23-2012, 06:12 PM | #16 |
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Any updates if you ran faster or if you troubleshooted the problem? Even though they are different tracks, a 1 second difference in the 1/4 mile is a substantial amount of time.
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05-23-2012, 06:14 PM | #17 |
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I just got the valves cleaned last weekend and it feels substantially smoother. There was a ton of buildup on some of the ports and valves. I have been really busy and unable to run it again. It probably will be at least three weeks until I can run it again. Unfortunately, it will be much hotter when I run it next.
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11-06-2012, 08:28 PM | #18 |
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Update
I just ran the car this past weekend, and I'm still dissapointed with the results. I've had the valves cleaned a few months ago. I was running the OTS Cobb E30 maps.
The condition and modifications: -78 degrees -ETS Intercooler -DCI -VRSF DPs -Near bald RFT (right rear especially) The time: 60': 2.269 330: 5.769 1/8: 8.589 MPH: 89.76 1000: 10.954 ET: 12.941 MPH: 113.25 My fuel pump seems to be having issues - a weird boost surge on the e85 maps and long cranks. Also getting wastegate rattle which should be addressed this Thursday. Curious to get your guys opinions on where I could start troubleshooting. Clearly the 60' is poor, but I'm curious how Rmnevo is making up so much more MPH in the back half??? |
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11-06-2012, 10:04 PM | #19 |
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Maybe my car is different since my mods are way different, but shouldn't you be shifting way sooner than 6500 rpm's. You're gonna end up in fourth no matter what so try shifting between 5600-5800 rpm's and that should land right back in the meat of the torque curve. I would only hold the gear that long if you were trying to avoid having to shift at all, but in 1/4 mile it doesn't matter you should be hitting fourth by the end anyway.
The trap speed is troubling so that needs to be addressed, but I'd experiment with the shift points you might pick up a tenth or two that way. |
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11-06-2012, 11:26 PM | #20 |
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First time I've seen this thread. Looking at your first runs your traps were only 104mph which doesn't add up given your mods. Your more recent slips show a healthy 113mph trap which is where you should be at. The 2.2 short time is very average though, if you can cut it down to 1.9 you should see a half second improvement. General rule is every 0.1 you shave off your 60ft short time is 0.2 off the 1/4 time. Practice the launch and you should be right. I recommend doing some logs to make sure everything looks good as well. I've been down the 1/4 with another 135i and I was 5mph faster on that night. 5mph = more than 5 car lengths. We got off the line together but you could see the difference in power.
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11-07-2012, 06:24 AM | #21 | |
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