MB_Forever

Somebody was saying the other day that they fixed it for this year's season, but I guess that remains to be seen.

By the way, it is only 2.5 to 3 mph off on the top-end trap speed according to VBox not 6 mph.... I wish it would be 6 mph though

JHDavis

I doubt they will fix it because I don't think anyone is complaining out there

How far it's off depends on the trap of the vehicle in question. 120mph is 3-4mph, 130mph is 5-6mph. Point being ATCO reads low in one lane (2-3mph) at 120mph, Sac reads high.

Are you VBoxing at 2 different tracks to compare or just comparing the Vbox to Sac only?

The first method would be the way to go since VBox times and traps are always different than dragstrips.

JL_C63

Congratulations Keith, very impressive

118E63

Hey how ya been man,havent talked to you in forever

118E63

So Mo,does that mean you really only went 115ish??

Dads C63

Thank you!!

These cars are a blast!! One weekend in Homestead road racing and the next in Maryland blasting down the 1/4 mile track!!

olszowa12

JL_C63 what is your best 1/4 time?

93turbocoupe

thanks for the pics. can you show some of the engine? is that race fuel in tnat box?

hhughes1

Wow!! I guess there are beasts and then there are BEASTS. Spending a weekend at Sebring with you and Dodger left me with a complex.....felt like I was driving a hybrid.

MB_Forever

Not sure if it reads that high at 130 mph. According to Alan's VBox data, at 132 mph, it was off by 2.5 to 3 mph. We ran the test at Infineon, Famoso, and at Sacramento

In the end, I think east coast guys have ATCO and MIR (both super-fast tracks) and west coast guys have Sacramento (also a fast track)

Only in -2000 ft DA

By the way, my highest trap speed was almost 119 mph common now.... you know I couldn't let Oldgixxer keep all the records to himself, I had to take the trap speed record away

Dads C63

Yes, thats nitrous fuel in the fuel cell. Here's another pic. Thats about all you can see under the hood.

Dads C63

Hey Bro,
We all know thats NOT true.
You're the stinking reason I'm road racing now!!

We are all just having FUN now!!

jacob502

Congratulations Keith. You are a 63 AMG master

JHDavis

Didn't he run 128 at Famosa and 135 at Sac? That's 7mph diff. Not sure if the VBox has any relevance unless you tested at both tracks and compared the differences vs the track timing equip.

I get where you're coming from but ATCO and MIR's timing equipment is legit (they don't read high, atco actually reads low), everyone knows (even those that work at Sac) that Sac's is optimistic.

I don't think that's quite the same thing. I wish they would fix it for you guys because I think Sac is still a better track than Famosa.

MB_Forever

You can't compare the Famoso run to the Sacramento run due to the following reasons:

1) At Famoso, he had to let off the gas at high speeds due to very high vibrations past 120 mph. So the car was not running optimally.

2) Famoso DA on that day was close to 1800 ft while Sacramento was at about -500 ft. At Famoso he ran 11.00 @ 128 mph and at Sacramento he ran 10.7 @ 135 mph. I think 2300 ft difference in DA is enough to create a 0.2 second difference in ET and at least 2 mph difference in trap speed.

3) At Famoso he did not have his light-weight battery and he was testing out a few new mods, such as, new killer chiller system, and new tune. So the car was not in a final stage. As you know, new mods take some time to dial in.

4) Famoso is at 615 ft physical elevation vs less than 30 ft for Sacramento. So even if conditions were the same, this physical elevation will still create a slight difference.

What we did was run the cars at Infineon since it is geographically very close to Sacramento and at about the same physical elevation. Also, it is one of the top-rated facilities on the west coast.

ATCO reads low only compared to the high reading left lane. It could be that the other lane reads high. Honestly I don't disagree with you except on the amount of speed that Sacramento is off by. I know that Sacramento's trap speed is probably off by about 2 to 3 mph and that they should fix it. However, they appear to be not. So Sacramento will remain a fast track for us west coasters. ATCO and MIR sometimes see DA that is close to -2200 ft, and very dense air that is sometimes combined with very low humidity. These conditions make those tracks super fast and can make the cars create an unbelievable amount of power as seen from all the numbers across the past few years.

Anyways, lets not de-rail this thread for Keith I think we need a whole new thread for Sacramento's trap speeds. There are rumors that they may have already fixed the timing equipment but who knows

Max.H

Niiice!!! 10.4 is hauling the mail.

dodger63

-2200 in the middle of December when it's 18* out

JHDavis

Ok, good to know.

From what I've been told every 700-750 feet of altitude is worth a tenth and a mph or so making that closer to .3 and 3mph. What was the actual temp if you can remember? Not to nitpick but DA (altitude) doesn't necessarily kill forced induction cars, but heat and humidity certainly will.

Ok again makes sense.

That's factored into the DA (physical altitude) so it wouldn't matter.

Sorry not following, what did you do at Infineon?

One lane is on the money, the other is low. I believe quite a few C63s have proven this by going to many east coast tracks and backing the accurate lanes times and traps at other venues in similar DA. Not an exact science but it never is

I still think it's safe to say that the amount the trap speed will be off is directly related to the speed of the car making a pass. The higher the trap the larger the difference it does make sense and I'm not just talking about MBs racing at Sac. A Fast track isn't the same thing as a False track.

It can get to -3500' but that's maybe 2-3 days per year. I would imagine sac at 30' above sea level has it's fair share of negative DA days in the winter too. I guess my point is, East coast tracks may be fast but it's not because of inaccurate timing equipment.


Agreed. Thanks for a civil discussion.

MB_Forever

Given your correction factor, his 11.0 @ 128 at Famoso would equate to 10.7 @ 131 mph at Sacramento. Add to that correction a couple of lighter mods and a not letting off the gas and you get 10.7 @ 133 mph, which would bring the error down to 2.5 to 3 mph.

With the 55k motor, because it is very inadequately cooled, DA does play a big factor. Definitely not as big a factor as on the 63 engines, but does significantly affect the times and traps. We've actually tested this more intensively 4 or 5 years ago.

I agree with you, but for some reason that was not always the case.... and I can't explain it. I've ran at tracks having different physical elevation but very similar DA values before and the track with the lower physical elevation always yielded better numbers.

We ran 3 cars at Sacramento and Infineon on back-to-back days while using the VBox to compare times. There was always a 3 mph variation across all 3 cars. Trap speeds for the cars were: 122 mph, 125 mph, 130 mph.

I agree.... still not an accurate assesment, but I guess depending on the racer, it maybe close enough

Absolutely.... the beams are said to have been setup too close to each other since the big accident a couple of years ago, which makes the trap sensor think the object is going through the beams faster than it really is. Consequently, the faster you go through the two beams, the more inaccurate it will read. However, I believe one of the pro drag people were saying that it maybe off by 5 mph at 160 mph or something along those figures. I guess we'd need more testing with faster cars to see where it stands

LOL... a fast track could be considered an inaccurate track as well

LOCO 05' E55

I believe the only difference between ATCO and MIR is the right lane reading slower MPH @ ATCO and the difference in great Prep at MIR compared to atco3...

My best traps have been (129.XXX ATCO) (131mph MIR)

I ran my car with the same mods and similar negative DA on both tracks and went almost 2 mph faster @ MIR, this off course after adding skinnies.

They are both great tracks and i doubt one is faster than the other equipment-wise.

propain

At MIR my vbox was always showing my MHP to be higher than my slips. By 1 mph. Right lane.

jrcart

Congrats Keith, very very impressive numbers.

bassn_07

Wow, Congrats Keith on an outstanding time! I'm glad to see your hardwork and constant drive to take your car to the next level has finally paid off. I haven't been on this site for a while now but after hearing what you've accomplished I had to come on and give you props that are well deserved.

As far as Sac...lol. The only thing I'll say about this is that I've only hit 135 at Sac one time, all the other runs have been in the 132-133 range. Does my car trap 135, of course not, do I really care...no. All I do know is that I'm very happy with my cars performance and what I've accomplished with it.

As far as Famoso, even though I had a few issues and only made a few runs (trailered my car very early due to problems), I was still the 3rd quickest car out there out of 40-50. Only being topped by a GTR and Vette. Regardless of excuses my car still held its own and performed well.

Once again, congrats Keith and all the other cars out there raising the bar. The 63 crowd has accomplished more than I ever thought possible.

Good luck guys and be safe!

dodger63

Is that "slip of the tounge?" Mhp or mph?

propain

mph... I think one run the vbox said I trapped 123.5. I was like.. YEEEEAAAHHH!! then the woman hands me the slip and I was like... ohhhhh.....