SleeperX

Does anyone have an idea as to how much a bad launch will impact your trap speeds. Ran over the weekend and spun really bad off the line. Had to let of the gas a few times to let the wheels catch. How much, if at all, do you think this impacts the MPH in the 1/4 mile. I realize it does impact the time, but what about the MPH. Thanks

Fikse

post all the time data, and we can look.... 1/4mile et/mph 1/8 mile et/mph, 60' etc...

if you want to get a good idea of your trap speeds, leave ESP on, and just jump on it slowly off the line for .5 sec, then hammer it....

most of the time the traps will be pretty consistant, good launch or bad...

BUT, if you have to keep letting off the gas down the track, then it will bring down the traps.....

Jakpro1

Yeah post er on up....we're here to help. We've all had *****ty runs before....sometimes even DerekFSU will tell ya, the tracks just SUCK!!

When you get a sec....let's take a look.

You'd be surprised how great that "quickly but smoothly without mashing" launch technique works. Fastest stock Benz in the US swears by it.

SleeperX

Will post slip later today? from memory though I believe times were as follows:
60 ft. .............1.8
1/4 mile............12.072
MPH.................115.8MPH
Recently got the Kleemann I/C Pump which I think helped tremendously. Had to drive 45 minutes to the track and ran it immendiately when I got there. Had a chance to run it 6x. Experimented with ESP off, shifting manually, etc. This was my last run of the day. Car never had a chance to cool off. Literally had no more than 5 minutes cooling period between runs.. Trying to break into 11s. This was frustrating, but I think with a cooler engine and a better launch I can get there. FYI, this was on PS2s.

KenE55

You call a 1.8 second 60 foot time a bad launch? That's about 0.1 better than my best ever...

SleeperX

Yes, spun like crazy off the line and had to let off the gas. It was actually a 1.88 or 1.87 (maybe). Not a 1.8 flat. Also my car is not stock. Has Renntech upgrades. ECU, pulley, headers, and airbox..

Kens-E55

Steve:

Your 60' and et are Very Respectable! To have a 12.0+ trap et, you should be knocking on the door of 120mph's trap speed. Based on your times, it would appear you do have a cooling issue .... as the motor is building boost thru the 1/4, the intake charge is probably getting to hot and the timing is being retarded...hence your low 115mph trap speed............

GET the cooling upgrade!!:zoom:

Fikse

1.80 - 1.89 is actually a pretty good launch.... and your ET and MPH line up pretty well.....

the ET and MPH don't line up with your mods though.... you should be pulling 120+ traps easily with your level of mods....

questions:

what track was it at? and what was the outside temps?

have you had the car dyno'd?

have you had the ECU service campaign done and the computer re-flashed by RENNtech?

SleeperX

I agree. I also think I should be trapping in the 120s.. I haven't had the car dynoed. Wanted to do it before the upgrades, but didn't get a chance to do so. Without a base run I figure to dyno now would be useless. I did have the ECU service campaign done and the computre re-flashed by Renntech. I ran it at Englishtown, NJ on Saturday afternoon. Temperature was in the mid to low 60s. Last week I got the Kleemann I/C pump upgrade because I thought my car was heatsoaking during the runs. It might run better cooler, as I ran it pretty hard to the track and once there I ran it 6x before getting the 12.072.

So do you think that my not achieving 120s has nothing to do with my launch?

Mad TKD

I think your 1.8 60ft has nothing to do with your 115 trap speed. Something else is holding you back. What tires was this done on? If it was the stock tires that is great!! Most likely it is a cooling issue like most have said.

Trap Speed = Much power your making
60ft = how good your traction is

KenE55

Based upon experience with my stock car, I have consistently found that a great launch reduces the ET but actually lowers the trap speed. You simply have less time to accelerate. My best ET (12.49) was one of the lowest traps (112.3), while my worst ET (12.676) was my best trap (115.95). I believe a good launch effectively shortens the race, which means you just don't have time to get to those higher speeds.

If I can get nearly 116 bone stock, I'm surprised so many modded cars have only marginally faster traps.

SleeperX

I am running on Michellin PS2s. I recently had the larger Kleeman I/C pump installed. Maybe I need to go with the Evosport Cooling Upgrade. Couldn't it be how I launch it though. A few times I had to get off the gas in order to stop wheel spin. A short pause might cause me a few MPH in a fixed distance. No?

Mad TKD

how are you launching the car? esp on or off

SleeperX

ESP on. I usually try to roll into full throttle. Thought I was doing it this weekend, but the car was still all over the place off the line. My best launch was the one that I posted and even that one wasn't great. I think the engine was heat soaked by the time I got to my last run considering that it was my 6th run of the day with only a 5 minute break between runs..

Mad TKD

well before You do anything else dyno the car. That will tell you alot. Then take it back to the track and let the car cool before you run(hood up).

medici78

I had a strange night once where I was running 106mph traps. I thought my car was broken. However, I noticed that the ESP light was blinking halfway down the poorly prepped track. Went to another track and it was running right on par with other E55 traps. I'm guessing the ESP was slamming on the brakes hard throughout the runs.

Fikse

I sent you a PM......

Grumpy666

Your observations have no real merit.

Think about this:

The car that gets to 60 ft the quickest is accelerating the fastest.

A car like the E55 will easily overpower the tires on a hard launch and give a poor 60 ft time. Now, if that same E55 is down on power, the tires have a better chance to grip and will produce a quicker 60 ft time. BUT, that same car will have a slower trap speed because it's down on power.

60 ft times and trap speeds are not highly correlated.

Ted Baldwin

..............I understand that it may not seem to make sense, but it is indeed the experience of many at the dragstrip that your trap speed does go down with improvement in your 60ft time. Infact you can tell a fake timeslip by noticing no decrease in tra pspeed with improvements in 60ft time. Perharps Fiske can chim in.

Ted

SleeperX

I would have to also agree. If I look at my time slips when I had the worst 60ft times, I had some of the best trap speeds. As a matter of fact, I ran a 12.06 second 1/4 mile with a trap speed of 120.65. My 60 foot was 1.956. Check out my earlier posts where I posted the slip.
https://mbworld.org/forums/w211-amg/141238-finally-tracked-car.html

rflow306

Your 60ft does not affect your trap speed as much as everyone seems to think. Something else is causing your drop of 5 to 8 mph, its probably the weather or most likely ic heat soak.

The car's 60ft will not change more than 1 to 2 mph of trap speed from my experience. Contrary to popular belief your car can 60ft better and still trap higher mph.

Ted Baldwin

..............I don't think that the 60ft time makes your trapspeed better. It is just an observation in the real world that you notice better trapspeeds when your 60ft time is not so good. I don't have an explanation for it. Maybe somene does. One explanation I have heard is that with very good 60ft time, your car bridges the distance from start to finish before WOT. This allows you to get to finish line quicker (better 1/4) mile time, but before your car gets enought time to accelerate to a higher trapspeed. I don't think that anyone is suggesting that a 5-8mph drop in trapspeed should be blamed on a good 60ft time. Heat soak and weather do affect 1/4 mile times and trapspeeds generally, and not related to 60ft times. Consistently you will notice the race that gave you your best 60ft time did not also give you your best trapspeed. Like a said before, this is one way to spot a fake timeslip.


Ted

Grumpy666

Here's some real-world fodder to graze on. The link below shows groups of time slips for the same car on the given day. Each group represents a different level of mods for that day. Take your time and scan down the 60 ft and 1/4 mph columns. I didn't plot the values in Excel, but in my head it formed a scatter plot, which indicates no correlation. For a valid comparison, stay within a group. It is nicely documented.

http://www.jumptronix.com/TeamJumper/Time_Slips.htm

I Googled 60 ft time trap speed to find this URL - it was the 7th listing on the 1st page.

Ted Baldwin

............not sure what I am looking at. Many have noticed that their best 60ft times resulted in a lower trap speed. If this has not been your observation, then no problem. Perharps your trapspeeds increase with better 60ft times, in which case you are very fortunate. Either way, no problem.

Ted