So Much for AWD - Page 25 - PeachParts Mercedes-Benz Forum

t walgamuth · #**361** 04-24-2013, 03:05 PM

The art of assigning cars to classes in scca autocross is based on actual performance capability, hence any AWD vehicle is handicapped much as in handicap horse racing with the intention to negate any design superiorities.....so its a worthless distinction to not win your class in scca solo. My 99 Miata was dominant when it first came out then newer cars were placed in the class and now they are dominant. One of the drawbacks of running in a stock class in scca autocross. Buy a competitive car and classifications can change next season and make it uncompetitive.

t walgamuth · #**362** 04-24-2013, 03:15 PM

D Modified (DM)
Modified Production and GT cars with internal combustion engine displacement
2000cc and under as follows:
A. The Mazda 12A and 13B Rotary engines are permitted in DM with
the following restrictions:
1. No replacement of cast iron engine case segments with aluminum.
236 — 2013 SCCA® National Solo® Rules
Modified - Appendix A
2. On the 12A engine, only side and rotor housings from 1974 to
1986 engines shall be used.
3. No replacement of 12A or 13B sections such as side plates with
those from other series engines, i.e. Renesis-type parts.
4. On 12A engines, no peripheral-porting or J-porting is allowed.
Bridge-porting that does not cut into the water o-ring is permitted.
On 13B engines, 4- & 6-port: Maximum porting permitted is streetporting.
No bridge-porting, J-Porting, or peripheral-porting.
B. Weight (with driver) vs. Displacement
Piston engines up to & including 1800 cc: 1280 lbs
12A rotary engines w/ porting restriction: 1280 lbs
Piston engines 1801 to 2000 cc: 1380 lbs
13B rotary engines w/ porting restriction: 1380 lbs
C. Performance Adjustments
AWD: Add 200 lbs
Modified Tub: Add 40 lbs
D. Weight Bias Adjustment - with driver sitting in the driver’s seat
RWD w/ less than 51% weight on drive wheels: Deduct 35 lbs
FWD: Deduct 35 lbs
AWD: Not affected
E Modified (EM)
Modified Production and GT cars as follows:
A. Weight (with driver) vs. Displacement
Piston engines up to & including 3200 cc OHC: 1700 lbs
Piston engines up to & including 4500 cc pushrod/OHV: 1700 lbs
2-rotor rotary engines w/ unrestricted porting: 1700 lbs
Piston engines unlimited displacement: 1800 lbs
3-rotor rotary engines w/ unrestricted porting: 1800 lbs
Electric powerplants (non-hybrid) 1800 lbs
B. Performance Adjustments
AWD: Add 300 lbs
Modified Tub: Add 50 lbs
C. Weight Bias Adjustment - with driver sitting in the driver’s seat
RWD w/ less than 51% weight on drive wheels: Deduct 50 lbs
FWD: Deduct 50 lbs

Here is what the SCCA thinks about the advantage of AWD. Above are the modified rules highlighted are the ADDED weight required if you run AWD.

ned2683 · #**363** 04-24-2013, 03:25 PM

Quote:

Originally Posted by t walgamuth

The art of assigning cars to classes in scca autocross is based on actual performance capability, hence any AWD vehicle is handicapped much as in handicap horse racing with the intention to negate any design superiorities.....so its a worthless distinction to not win your class in scca solo. My 99 Miata was dominant when it first came out then newer cars were placed in the class and now they are dominant. One of the drawbacks of running in a stock class in scca autocross. Buy a competitive car and classifications can change next season and make it uncompetitive.

agreed a subaru sti does not belong in that, too heavy (around 600lbs heavier than an S2000) subaru people go to stu or bsp where they are more competitive and don't event bother going to Bstock.

however, keep in mind that i was simply answering your post number 264:

Quote:

Originally Posted by t walgamuth

I guess you have not noticed how the Subies dominate the stock classes they run in. Heck they aren't even very well balanced, very nose heavy. If they were balanced theyd be even faster. I am not aware that any subies fit into BS or AS and run head to head with s2000s. It may be different other places but I doubt it.

and post Number 273:

Quote:

Originally Posted by t walgamuth

You guys have dreamed up some theoretical scenario which cannot be duplicate in the real world. In the real world 4wd rules racing when it is legal. Show me scientific proof I am wrong.

so autocross B stock is a proof where a vehicle in the same class that allows both that RWD dominates.

Quote:

Originally Posted by t walgamuth

D Modified (DM)
Modified Production and GT cars with internal combustion engine displacement
2000cc and under as follows:
A. The Mazda 12A and 13B Rotary engines are permitted in DM with
the following restrictions:
1. No replacement of cast iron engine case segments with aluminum.
236 — 2013 SCCA® National Solo® Rules
Modified - Appendix A
2. On the 12A engine, only side and rotor housings from 1974 to
1986 engines shall be used.
3. No replacement of 12A or 13B sections such as side plates with
those from other series engines, i.e. Renesis-type parts.
4. On 12A engines, no peripheral-porting or J-porting is allowed.
Bridge-porting that does not cut into the water o-ring is permitted.
On 13B engines, 4- & 6-port: Maximum porting permitted is streetporting.
No bridge-porting, J-Porting, or peripheral-porting.
B. Weight (with driver) vs. Displacement
Piston engines up to & including 1800 cc: 1280 lbs
12A rotary engines w/ porting restriction: 1280 lbs
Piston engines 1801 to 2000 cc: 1380 lbs
13B rotary engines w/ porting restriction: 1380 lbs
C. Performance Adjustments
AWD: Add 200 lbs
Modified Tub: Add 40 lbs
D. Weight Bias Adjustment - with driver sitting in the driver’s seat
RWD w/ less than 51% weight on drive wheels: Deduct 35 lbs
FWD: Deduct 35 lbs
AWD: Not affected
E Modified (EM)
Modified Production and GT cars as follows:
A. Weight (with driver) vs. Displacement
Piston engines up to & including 3200 cc OHC: 1700 lbs
Piston engines up to & including 4500 cc pushrod/OHV: 1700 lbs
2-rotor rotary engines w/ unrestricted porting: 1700 lbs
Piston engines unlimited displacement: 1800 lbs
3-rotor rotary engines w/ unrestricted porting: 1800 lbs
Electric powerplants (non-hybrid) 1800 lbs
B. Performance Adjustments
AWD: Add 300 lbs
Modified Tub: Add 50 lbs
C. Weight Bias Adjustment - with driver sitting in the driver’s seat
RWD w/ less than 51% weight on drive wheels: Deduct 50 lbs
FWD: Deduct 50 lbs

Here is what the SCCA thinks about the advantage of AWD. Above are the modified rules highlighted are the ADDED weight required if you run AWD.

see my post #261:

Quote:

Originally Posted by ned2683

Agree'd, and on a race car that you have to add weight to bring up to minimum weight the AWD may have advantage.

so if they were to keep the same weight, then AWD will have advantage in undesireable conditions. hence SCCA agree's with this and levels out the playing field.

t walgamuth · #**364** 04-24-2013, 04:03 PM

Quote:

Originally Posted by ned2683

agreed a subaru sti does not belong in that, too heavy (around 600lbs heavier than an S2000) subaru people go to stu or bsp where they are more competitive and don't event bother going to Bstock.

however, keep in mind that i was simply answering your post number 264:

and post Number 273:

so autocross B stock is a proof where a vehicle in the same class that allows both that RWD dominates.

.

see my post #261:

so if they were to keep the same weight, then AWD will have advantage in undesireable conditions. hence SCCA agree's with this and levels out the playing field.

The AWD is an advantage at ALL times, more so if it rains

ned2683 · #**365** 04-24-2013, 05:17 PM

Quote:

Originally Posted by t walgamuth

The AWD is an advantage at ALL times, more so if it rains

going back on what you say?:

Quote:

Originally Posted by t walgamuth

So we all agree that 4wd is better in any condition in which traction is limited?

sounds like i half got you convinced on traction limited case and now you are going back to sticking to your guns.

FIND me a car that AWD did not add weight to it

or

Lie to me and tell me a heavier car handles better than a light car.

ned2683 · #**366** 04-24-2013, 05:20 PM

Quote:

Originally Posted by t walgamuth

The AWD is an advantage at ALL times, more so if it rains

also just making a statement while ignoring all my points does not make you right.

here let me do it

RWD is faster ALL the time.

Skid Row Joe · #**367** 04-24-2013, 05:20 PM

Quote:

Originally Posted by layback40

Well to all you arm chair experts who wish to use what ever "science" you can claim to give an opinion on this. A university in Japan did some work for Subaru about 10 years ago. They conducted a series of tests using one of the Subaru AWD's. They undertook cornering tests with AWD, rear wheel drive only connected & front wheel drive only connected.
One of the many results was that that when they compared maximum cornering speeds of the 3 configurations, the AWD showed a significantly higher speed. This was examined at a 95% confidence level with the null hypothesis being rejected. The rear wheel / front wheel comparison did not achieve a null hypothesis rejection at the 95% confidence level.
This is very definitive & for those who wish to understand better, best remember what you were supposed to have learned 1/2 way through your undergraduate engineering studies.

Quote:

Originally Posted by ned2683

care to provide a link to this study? I learned to check my sources 1/2 way through my undergraduate engineering studies. i would really like to read "A university in Japan did some work for Subaru about 10 years ago."

was it done on the same car and disconnecting front an rear wheels? or did they remove the rear differential and drive shafts for the front drive version and vice versa for the RWD?

2009 Infiniti G37x S Sedan - First Test - Motor Trend

While the all-wheel-drive G37x S would likely fair considerably better on snow-covered roads than the standard G37 S, on hot, dry asphalt, it falls slightly behind. The only major difference between the 2009 G37 S sedan we tested late last year and the G37x S sedan we just tested is the inclusion of Infiniti's "Advanced Total Traction Engineering System for All Electronic Torque Split" all-wheel-drive system lifted from Infiniti's crossovers, along with the seven-speed automatic transmission. Both cars featured the same 328-hp, 3.7L V-6 producing 269 lb-ft of torque and both were equipped with the optional Sport package. The ATTESA-TS all-wheel-drive unit adds just over 150 lb of curb weight over the rear-drive model, tipping the scales at 3859 lb. The added weight and drivetrain loss make themselves apparent at the track. The G37x S was nearly half a second slower to 60 mph and through the quarter mile than the G37 S, hitting 60 in 5.4 sec and tripping the lights at 13.9 sec at 100.5 mph. Braking was similarly affected, with the G37x S stopping 10 ft farther than the G37 S, needing 120 ft to come to a halt from 60 mph. This can also be explained by the G37x S' smaller brakes, as it doesn't get the same upgrade that the G37 S does with its Sport package.

1. please send that study to Infiniti, they didn't get the note.

2. also please send that study to BMW, so they can make their M3, M5 and M6 AWD, they have mistakenly made their flag ship models with the wrong drivetrain. also their Xdrive models are slower than their normal counter part which cannot happen according to this unlisted study.

3. Also send that study to Ferrari as all but one car is AWD, they could have done a lot better building AWD cars.

4. Send the study to Mini, as their FWD Coopers are faster than their AWD coopers.

5. Send that study to Lexus for their IS, their AWD models are slower than their RWD

Unless I missed something, and to be fair - neither poster is linking data to support their claims above, other than ned posting the Infiniti 0-60 mph and snow test data.

What ned provided was Infiniti's marketing data, seemingly which reflects that from 0-60 mph, the lighter-weight 2WD is faster than the AWD, as well as the AWD being superior in snow. Is any of this a surprise? I think not.

ned is also speaking for BMW/Ferrari/Cooper/Lexus no linked data, in claiming their 2WD cars are faster than their AWD cars - but again, provides no data other than the reflective Infiniti data claim of a drag racing situation where they'd be faster too. Again, no surprise here.

The ability of a 2WD car to outrun an AWD like car in a drag racing test of 0-60 mph, where the 2WD car gains sufficient traction off the line, is no great shakes or achievement. In fact I would expect the 2WD to prevail.

layback 40's post reflects "cornering" claims in the Subaru brand, whereas ned's post contains no controverting nor relevant data reflecting "cornering data" against layback40's post.

ned2683 · #**368** 04-24-2013, 05:28 PM

Quote:

Originally Posted by Skid Row Joe

Unless I missed something, and to be fair - neither poster is linking data to support their claims above, other than ned posting the Infiniti 0-60 mph and snow test data.

What ned provided was Infiniti's marketing data, seemingly which reflects that from 0-60 mph, the lighter-weight 2WD is faster than the AWD, as well as the AWD being superior in snow. Is any of this a surprise? I think not.

motor trend does not work for infiniti, did you click the link?

Quote:

Originally Posted by Skid Row Joe

ned is also speaking for BMW/Ferrari/Cooper/Lexus no linked data, in claiming their 2WD cars are faster than their AWD cars - but again, provides no data other than the reflective Infiniti data claim of a drag racing situation where they'd be faster too. Again, no surprise here.

fair enough, these are my observations and not fact

Quote:

Originally Posted by Skid Row Joe

The ability of a 2WD car to outrun an AWD like car in a drag racing test of 0-60 mph, where the 2WD car gains sufficient traction off the line, is no great shakes or achievement. In fact I would expect the 2WD to prevail.

actually with lower HP the RWD will win, but once the HP is above the "street tire limit" the AWD will win in a drag race. this assumes there are the same gear ratio used in both cars the infinity example was the only one that had track/stopping data. If you wanted a 0-60 times then it would have been all over the board, as in 328i RWD/AWD but then you get in 335i's the AWD>RWD in 0-60 times.

Quote:

Originally Posted by Skid Row Joe

layback 40's post reflects "cornering" claims in the Subaru brand, whereas ned's post contains no controverting nor relevant data reflecting "cornering data" against layback40's post.

OMG WHAT data, he made a comment on some "japanese university study for subaru" then said it was super secret and no-one has seen it other than need to know basis, does that pass as evidence these days. this to me tells me he was BSing and i called him out on it and he cant produce it so he covered it up.

Skid Row Joe · #**369** 04-24-2013, 05:30 PM

Quote:

Originally Posted by cmbdiesel

Ned, I fear you are wasting your time here. You'll never convince some of these folks. They will continue to demand more and more detailed information from you so they can frame their argument just outside the border of your well supported position, all the while never backing up a single incredulous claim of their own.

Please read Post #367 above/to understand how ned presented oranges to an apples discussion with layback40.

ned2683 · #**370** 04-24-2013, 05:34 PM

Quote:

Originally Posted by Skid Row Joe

Please read Post #367 above/to understand how ned presented oranges to an apples discussion with layback40.

??? i'm stumped, layback said the same car with 3 different drive trains the AWD cornered better than the RWD. i gave an example of a G37 where same car 2 drivetrains RWD handled better than AWD?

rickmay · #**371** 04-24-2013, 06:11 PM

DRIFT Diesel Mercedes W123 with SCANIA turbine - YouTube

If you didn't notice, also, no roll, no dip, whether going forwards or backwards.

(one crazy Finlander)

t walgamuth · #**372** 04-24-2013, 06:33 PM

Quote:

Originally Posted by ned2683

going back on what you say?:

sounds like i half got you convinced on traction limited case and now you are going back to sticking to your guns.

FIND me a car that AWD did not add weight to it

or

Lie to me and tell me a heavier car handles better than a light car.

You are not thinking this through. The D and E modified class cars are limited by weight and displacement. If a configuration is an advantage in order to handicap it they might limit horsepower (like requiring an annulus on a Honda Fit engine if used in a Formula ford) or they might require extra weight be added, like with AWD. So the D mod car if AWD is required to carry 200 extra pounds, the E mod an extra 300#. they don't do it because AWD is an advantage in the rain they do it because its an advantage in the dry.....obviously also more of an advantage in the rain.

I have not changed my position at all.

Skid Row Joe · #**373** 04-24-2013, 06:50 PM

If I cannot succeed in getting another to understand the aspects of clarity in the terms they themselves used in linking to them, as well as the testing differences as presented by them, i.e. my last two posts with examples CCed and referenced - I don't know what to tell them.

I cannot get any more clear than crystal clear.

ned2683 · #**374** 04-24-2013, 07:10 PM

Quote:

Originally Posted by t walgamuth

You are not thinking this through. The D and E modified class cars are limited by weight and displacement. If a configuration is an advantage in order to handicap it they might limit horsepower (like requiring an annulus on a Honda Fit engine if used in a Formula ford) or they might require extra weight be added, like with AWD. So the D mod car if AWD is required to carry 200 extra pounds, the E mod an extra 300#. they don't do it because AWD is an advantage in the rain they do it because its an advantage in the dry.....obviously also more of an advantage in the rain.

I have not changed my position at all.

i dont agree with you, but i dont see how we can settle this short of the person that made the rule clarifying it.

the formula ford requires a restriction plate most likely because you cannot have a AWD formula ford as they are mid mount RWD no?

and i think we are saying the same thing here, an AWD can have advantage in the dry considering there is no weight penalty. If you have can have the same weight then why not use AWD? if they run in ****ty courses, or in the wet they would blow the other cars off the door. and if they are running on a dry track that all the grip and power can be had then they should handle the same as a RWD car as well. so to level it out they added weight penalty as an AWD car is typically heavier.

you are probably aware of this that despite running R comps on a dry pavement, not all locations have the same grip. I ran on a course with "fresh" concrete and it was surprisingly slippery (had a talcum like coating on it)

ned2683 · #**375** 04-24-2013, 07:15 PM

Quote:

Originally Posted by Skid Row Joe

If I cannot succeed in getting another to understand the aspects of clarity in the terms they themselves used in linking to them, as well as the testing differences as presented by them, i.e. my last two posts with examples CCed and referenced - I don't know what to tell them.

I cannot get any more clear than crystal clear.

i'll be honest with you i have no idea what you are saying half the time. You dont really bring any new information to the thread and simply agree with the dude that cited a study that he cannot and will not provide.

Yes i cannot provide a scientific study that proves that RWD is faster than AWD as i do not believe anyone has done one. I can make up a study and cite it if that would compare apples to apples?

so i try to bring as much real world data and testing to the discussion.

why do you keep using the japanese study that he cannot and will not provide as real evidence? do you believe everything you hear?