Gondon

You need to merge all 3 of your threads!! Why did you make 3 ROFL?

DAGREEKNYC

Damn i need some forced induction !!!!!!!!!!!!!!! Sick times .

LitiGATOR

I witnessed it in person; pretty impressive to say the least. SGC is also a great driver.

MJ50

Vic55

Slow Down!!!!!!!!

beauphus

excellent run. will u be going to PBIR for the supercar weekend meetup and track event on feb 26th? i think a bunch of the s.fla members here will be going. would love to see this in person

https://mbworld.org/forums/events-ga...-ride-gtg.html

SGC

Seriously.

The SL, CL and S classes all have the same 65 motor but have separate sections in the forum. Some guys don't venture to other sections and may want this information. I would (hence three posts). Also, a lot of E55 guys move up to a 65 (like me) and would like to know this information as well.

The idea of the forum is to spread information.

Anything else?

SGC

Thanks.

The event looks like a great time.

I'll try to make it.

E55AMGGG04

Dam thats FAST !! Nicee Congrats

Marcus Frost

Hi SGC,

So, last night I decided to look at your time slip compared to mine. I also have a 65, although obviously an R230. I noticed something a little strange that maybe you can help me out with. You MPH 10mph higher than I do in the front 1/8th (my best is 95 ish mph, so your car is flying through that front half), but in spite of the fact that you have copious more amounts of HP/TQ than I do, since I am stock, we both pick up almost the same paultry ~26MPH on the back 1/8th (the same time I did 95mph in the 1/8th I finished at 121 at the 1/4)?

Now I am not implying anything here, I would just maybe like to get an explanation for how you or RENNTech would explain that? It seems that with your RAM-AIR setup, your extra cooling, etc., etc., you would benefit a LOT more at speed (after all, RAM-AIR will infact ram more air the faster you are going, and cooling is well known to gain efficiency the more air that is flowing over the cooling components) but in fact you barely picked up any MPH on the back half of the track for all the power/cooling/etc you have?

For what it's worth, I would be more than happy to post my time slip, if it is necessary. My DA was nowhere near as favorable as yours. I am stock except for an upgraded heat exchanger and 20" wheels (which I'm sure don't help my times)

Any input would be appreciated.

-m

AMGSC

Interesting....Could a really great launch have something to do with that? Traction? But the DRs are the same ones used by everyone. Suspension mods? I don't see any...

SGC

If you have your time slip to post, that would be great.


Take a look on dragtimes and you'll find that to be common. Many variables at play. With the small intercooler capacity of these cars with the stock reservior, by half track, there is no doubt that the air being forced into my engine is heating up even with ram air. More importantly, the faster you travel, the more aerodynamic drag you encounter. Also, at 106 mph vs. 95 mph, I am eating up the last eighth mile approx. 15 feet per second quicker than you. By the end of the quarter mile, I am consuming real estate nearly 20 feet per second faster than you (using 121 v. 134 mph). Moreover, accelerating a car from 106 takes considerable more power than accelerating the same car from 95 mph. If you have ever seen the video of the Veyron accelerating, it is clear as the speed increases the amount of power it takes to accelerate a car becomes exponential. Picking up 25 mph from 96 mph is easier (takes less horsepower with same car) than picking up 25 mph from 106 mph. However, I picked up nearly 28 mph, in less time.

To compare apples to apples, using the example of a cl65 (your SL is lighter) on dragtimes that went 11.61 @ 120.3, at the eighth mile the car was traveling 95.6 mph. To travel at from 95.6 to 120.3 (24.7 mph), it took that car 4.1 seconds http://www.dragtimes.com/Mercedes-Be...lip-15436.html.

My car on the other hand, fighting 106 mph wind, accelerated almost 28 mph to nearly 134 in 3.7 seconds in the same eighth mile. http://www.dragtimes.com/Mercedes-Be...lip-20351.html. That is significant. If we started your car at 106 mph at the eighth mile, there is no way your car would accelerate to 134 mph in 3.7 within the last eighth of a mile with the power you are currently making.

In short, the power of my car is shown in the time slip.

SGC

Marcus,

Another example to assist you understand why cars accelerate slower at higher speeds due to aerodynamic drag and other factors, consider the following:

I have raced at numerous standing mile events. At said events, stock Z06s and Vipers that trap nearly 130 mph in the quarter mile, most of the time, only pick up another 30 - 35 mph by the end of the mile (160 - 165 mph) despite having another 3/4 of a mile at wide open throttle.

Benz-O-Rama

Are you still running a methanol injection system?

SGC

Almost burned my car to ground. Answered here : https://mbworld.org/forums/cl55-amg-...-record-3.html


Tried it and nearly burnt my car to the ground. Renntech wouldn't put it on. Had another shop do it. Tried methanol for the mile run since I thought it would be helpful since the car would be on boost for a longer time. In the mile it ran the same with and without. Also, on the dyno with good fuel methanol made no difference.

When a compression fitting came off, sprayed my exhaust manifold with methanol and my engine bay caught on fire, I was done with methanol. My wife wouldn't ride in the car after she heard what happened. Too flammable, can't see flames and no real gain for the risk.

Benz-O-Rama

Gotcha.

Too many threads started about the same thing. I must have missed the one in the CL forum.

Methanol is no joke. We used to run it in one of our VW drag cars. Didn't realize it was on fire until the paint started bubbling.

Marcus Frost

Before I go into my response, I just want to say that with all due respect this isn't my first rodeo and I have been drag racing for the past 10 years so I know or thing or two about it. I just want to put that out there because it seems to me that your responses are from a more authoritative perspective and it may be in the best interest of this discussion to establish a baseline of experience as to not spend needless effort in educating, rather to focus on discussing.



*PURE* 93 octane fuel. 20" Pirelli PZero tires @ STREET PSI (no lowered tire pressure). +1600DA. No ice, no magic pixie dust. Pulled off the highway, into the staging lines. Let her cool down a bit, and clicked this pass off.

First off, I am aware that the V12s have trouble on the back half of the track. However comparing your car, which is the current "record holder" with all new "goodies" on it to what on dragtimes are 99% stock or stock + ECU/TCU cars is simply apples to oranges. You have additional mods that directly are there to help on the top end not to mention the added octane with the super low DA - yet I am not seeing much improvement at all.

The difference in IATs, from what I have logged, between the 10mph difference we have, is almost negligible, especially since you have cooler air coming in and a better intercooler setup from RENNTech. I'm sorry, but in my experience using drag to explain this has never been the case.

My friend, this is quarter mile racing, not mile racing. The aero drags differences between our cars for the most part is negligible except for the very last part of the track. What you are suggesting here does NOT possibly equate to the discrepancies I am talking about. Your CL actually has a slightly better drag coefficient than I do in addition to having OVER ONE HUNDRED more RWHP than I do, not to mention more RWTQ, and you are trying to tell me that you are blaming the inability for your car to pick up any more MPH on the back half is the difference in aero drag between 121 and 134mph? It just does not add up, my friend - but hey, maybe I am wrong?

I have seen such discrepancies before, especially in the domestic racing circles. Usually what was behind it there was simple, a gear. Going to a 3.73 or a 4.10 would easily pick you up a good front half and usually would net you a great ET, although your MPH would obviously suffer. I noticed you said RENNTech added an OS Giken LSD - was the LSD geared with the stock gearset or was yours modified?

Of course it does and there is more power needed, however in the low 100mph range you aren't talking about 100rwhp worth of power. At 180mph or 200mph+ - the requirements grow exponentially, but I just do not agree with the differences required in this particular setup.

That is an interesting observation but again, just comparing those two slips doesn't quite take into consideration that you ran in what appears to be much more favorable DA - +1150 for the CL, and -682 for you. If you look at the DA for my pass, I was at +1600 or so. I am not one to speculate too much on DA but the truth is for this discussion that is an important consideration, since you are trying to use other people's passes with not as favorable of conditions to compare. With DA as low as yours it's not necessarily very beneficial to the overall run, but it's not unreasonable to say that from what I've seen a difference of 1500-2000DA is enough to warrant saying that the guy with the higher DA could easily pick up a couple of MPH and lose a couple of tenths on his ET. I think realistically my car could have picked up the 25mph on the back 1/8th in 3.9 or maybe even 3.8 in your conditions or your car would have done it in 3.8 or maybe 3.9 in mine.

The way I see it, or I should say in my experience, for two cars with identical engines, similar CD, etc - when one put 10mph on the other at the 1/8th, that almost always meant than on the back 1/4 it would not have been pretty for the car who was behind. I cannot explain why in this situation it is like this, I can only speculate with what I have seen.

You do make a statement that to some extent should be acknowledged. Your car trapped 134mph according to your slip. That is very, very fast. Regardless if something looks to me a little "off" - you ran a 10.6 @ 134mph. That is very fast.

Respectfully,

-m

SGC

I thought it was a discussion as well.

My car has the stock gear ratio, with a 26 inch tall tire drag radial.

For your analysis to make sense, the torque multiplication benefit of a change in gear ratio would have stop working at the eighth mile. As`you know, the same torque multiplication occurs every moment the car is accelerating, even during the back half of the quarter mile.

I put 10 mph on you by the eighth and 13 mph by the end of the quarter. That's what is supposed to happen.

Look at Marko's 10.73 run with a stock gear. He put 8 mph on you in the eighth and 10 mph by the end of the quarter. He is running a stock gear as well and has more than 100 rwhp than you. Again, that is what is supposed to happen. In fact, Marko has a 10.76 run where he put 8 mph on you in the eighth (104) and 9 mph on you by the end of the quarter (129).


Look at Godspeeds splits on his 10.72 @ 128 run. 6 mph (102 mph) on you in the eighth and 8 mph (128 mph) on you at the end of the quarter.

If your theory is right, I guess everyone changed their gears. If not, that's the way its supposed to be.

Since everyone has stock gears, that's the way its supposed to be with these cars.

I know it seems like there should be greater gains on the back half.

Marcus Frost

If it weren't 1am, I'd do the calcs on the tire size... but have you run the #s to see how the tire may have affected your final gear ratio?

Not necessarily. The taller gear manifests itself at higher speeds simply because of the escalating effect torque multiplication has at speed (which, as you mentioned before, is due to the laws of physics adding resistance to a vehicle as it's speed increases not to mention the alteration of the final gear ratio in all gears). Additionally, the fall off in MPH on the top end can also be affected by a number of other factors, including things such as an extra gear shift before going through the traps.

With the discrepancy in conditions, I have trouble swallowing that.

I know Marko personally and I give him a lot more leniency simply because he was pioneering a lot of this stuff on his own with the help of some very talented local guys. His passes involved a lot of trial and error that could explain certain discrepancies. Your car, while taking the title, has the backing of a very big tuner along with some "buzz worthy" parts, so unfortunately you do not warrant the same luxuries . I would hope that the cost/engineering behind your RENNTech components would yield results that are better than the stuff being hand built by guys with no where near the access to resources that RENNtech has.

In addition to all this, let's also face it - your car, if we go by "uncorrected MPH", is more powerful than Marko's.

I'm not sure I feel comfortable comparing Jody's car to yours simply because yours has a lot more in parts and labor than his does. It also doesn't take into account the kit on Jody's car was still experimental and had still some adjustments to be made. I see where you are coming from, but I'm just not really buying this justification for your big dollar RENNTech kit to justify it's lack of top end performance by comparing your car to the significantly less expensive prototype VRP kits - especially knowing that RENNTech's attitude towards the VRP kits is that their kit is vastly superior and involves an R&D budget equal to the GDP of Belgium in order to justify the exorbitant prices they charge for what usually are products of merely comparable quality to those that exist from other companies.

I have always been disappointed with how the V12s do on the back half of the track, and even though, again, I see where you are coming from by using other big HP V12 cars to show they don't pick up much MPH on the back 1/2 of the track... the truth is with the conditions you ran in, and the fact that your car has the "latest and greatest" from RENNTech, it is disappointing to me to see that the best RENNTech has been able to come up with now in 2010 is what is merely comparable to the prototype kits from much smaller tuners.

Zod

So let me get this right...You are not impressed even when the guy currently holds both track and dyno records

Do you have a problem with people breaking records?

Seems like the same trend you did with Alan when he did...no offense intended, it's just the way I read your posts... and now you are mocking the big tuners....when If I recall correctly you mocked the lesser tuners for quality/build/ reliability etc

am just saying

Fikse

no point in comparing the two cars, they are way too many variables and changes.... different tracks, weather, mods, power, torque, weight, aerodynamics, etc.. you could sit here for a year picking apart the two and still come up with nothing... picking up 28 MPH on he back half is a strong car in either car, but starting at 95 vs 105 MPH is a totally different situation....

add 150HP to the SL and let's see what happens...

my ACR consistently picked 34+ MPH in the back half that night.... which means... nada...

Marcus Frost

No, and I apologize if I came out that way. I did conclude my first rebuttal with the acknowledgement that SGC ran a 10.6 @ 134mph. It's freaking fast. Just because I question some of the details to his slip does not try to discredit him from making a that big pass.

I find my role as Devil's advocate to be unpopular on this board but the truth is I don't take anything for it's face value and I question everything. Being around the aftermarket game for years teaches you to do that. If people want to get offended by that, it's their prerogative. I raised legitimate questions on this run that maybe I am wrong about, or maybe I am right about. I find that the MB community in general seems way too complacent about what people post and maybe it's because they don't have the knowledge or experience - they don't post questions or comments other than those that acknowledge whatever has been posted. Regardless of the reason, I like to ask questions and hopefully it will encourage others to do so as well, because asking questions is NEVER unhealthy and fundamentally is part of why these message boards exist, isn't it?

As for my "mockeries" - I am an equal opportunity critic. If you are small and don't know what you are doing, or if you are big and think everyone is an idiot for questioning you, it is all the same in my book.

-m

Vic55

well said ... its always apples and oranges unless you line up at the same time.

nick 55

You aren't nearly as unpopular as I am .

Nick

SGC

Thanks Marcus.

You must be the life of the party. While fulfilling your self proclaimed MBWorld role as "forum devil's advocate", I hope you don't slap any small children or push any feeble old women down a flight of stairs to get answers. Nothing good can come of that.

Also, I have a few questions that I was wondering if you could help me with:

1) Is Bigfoot real?
2) Where is Jimmy Hoffa?;
3) Who kidnapped the Lindbergh baby?,and last, but not least,
4) Is it true that Elvis and Jim Morrison are still alive and living together as lovers in Vienna, Austria?

All kidding aside, I appreciate your conviction.

I guess you misconstrued my point when I mentioned Marko's and Jody's CL. If you have ever read any of my posts, you'll notice that I have always applauded both of their efforts. They have done great things with their cars and have run great times. I happen to live in South Florida and have RENNtech in my backyard. I respect their work and have chosen to use them. That shouldn't bother anyone. My point in mentioning Jody's and Marko's cars was to point out that these cars (CL65s - mine included) do not pick as much mph as you would think on the back end (to answer your original inquiry). My car is included in that group. It was not my intent to proclaim that my car is better. We are all enthusiasts who are trying to make our cars faster. When someone goes a 10.50 with a CL, I will be happy for them.

I wish all my forum brothers and sisters well when they modify their cars. I know from my own experience things you thought would work sometimes don't, and things you thought wouldn't do anything - surprise you.

Anyway. I wish you the best with your cars.