DSE Suspension Testing

[Stuart Adams]

Anybody see the latest testing numbers reported on the DSE suspension upgrades vs. stock?

[907rs]

Are they published somewhere Stuart?

[JV69z/28]

The article is in this month's Super Chevy with the orange Camaro on the cover. The skid pad numbers before the four link with stock rear suspension with DSE front suspension are .81 with the stock rear leafs and .84 with the DSE 4 link. There is some debate whether or not the slollom speed is correct. It was real high like 58 MPH or something like that. Steve Rupp was suppose to check on that and report back today. There is a multiple page post over at www.pro-touring.com in open discussion about the story. Sorry I didn't link it. Check it out.

[Speedster]

The one that killed me was the severe change in 1/4 mile E.T. From a 15.16 to a 14.28 directly attributed to the QuadraLink versus the leaf springs - now that's planting your tires !!!

[Steve1968LS2]

The numbers are wrong.. must be a typo or a bad use of the formula..

the car did not run the cones at 58.39 mph.. no car ever has come close to that, especially on radial street tires (not R compounds)..

I don't know how the writer came up with those numbers, but they are not possible. The car was not tested by us so I don't have the tech sheet. More than likely they ran the test and screwed up the formula. If I knew the time through the cones I could calculate the correct MPH. The writer is not a Super Chevy staff writer, freelancer?

Alcino's car ran the cones at 48.1 and I know that car didn't beat it by 10mph.. a new C6 vette couldn't do 58mph, heck.. not even 49.. lol

For comparison (420ft cones)

g/28 = 46.48 mph
Alcino Mustang II = 48.1 mph
red '69 Camaro tested in the same issue as the DSE car = 48.5 (another one of our higher scoring cars.. actually the highest musclecar)

All three of these cars were running super sticky tires.. See a pattern?

There is NO such thing as a 125 foot skidpad.. it's 200 feet...

Look at it this way.. thier grip was .81 right? Alcino's was .99 right? Then how could they best his cones by 10mph if they had a .18 DEFICIT in grip?

Typo or bad math.. I don't think anyone was being dishonest.

Formulas:

420ft Slalom Equivilants

420/time = ft per sec x 3600 / 5280 = mph

[Mean 69]

15.16, nor 14.28 are very respectable with a 400+ HP 383 crate motor, independent of the improvement in times. Something is screwy.

Could they have been running the wide cones, Steve? I'd bet, and in this case, well.....
M

[JV69z/28]

Hey Steve when you say red Camaro are you talking about the car used in the Heidts spindle test? If so what do you think of those numbers? That car has the dropped spindles and narrowed control arms. They don't list the tire sizes and wheel specs (I wonder why) but the numbers for that car are world class and right there with the DSE stuff. Is that possible? If so to get that low down look that may not be such a bad option. Could you elaborate? Thanks.

[Steve1968LS2]

Hey Steve when you say red Camaro are you talking about the car used in the Heidts spindle test? If so what do you think of those numbers? That car has the dropped spindles and narrowed control arms. They don't list the tire sizes and wheel specs (I wonder why) but the numbers for that car are world class and right there with the DSE stuff. Is that possible? If so to get that low down look that may not be such a bad option. Could you elaborate? Thanks.

All I know about that test is that those were the numbers the car ran. I have the run sheet and I double checked all their calculations.

It ran the best times with the Nitto tires. I could easily find the tire and wheel sizes.

It's all in the tuning.. hell, Alcino ran numbers about that good and better than most of the exotic stuff and his suspension certainly wasn't exotic by any stretch..

I don't understand you comment about the "low down look".. of the red Camaro?

Also, I should restate that I am sure the DSE deal performed well. It's just that those numbers are not possible given the data I read. According to that the car was way faster than any other car, even a new vette, BEFORE they even installed the parts. lol

[Steve1968LS2]

15.16, nor 14.28 are very respectable with a 400+ HP 383 crate motor, independent of the improvement in times. Something is screwy.

Could they have been running the wide cones, Steve? I'd bet, and in this case, well.....
M

Don't know.. this test wasn't done on this coast so I have no idea. You've been to our tests and you have seen the equipment we use to test. Radar and sensors and all the goodies. Maybe they used a stopwatch. I doubt they cheated since the numbers were so far off, and I know DSE to be an honest company. I think it was either bad math, a transposition or bad data gathering (equipment).

Mark, can you see a car on hard tires being 10mph faster than Alcino's car on the race rubber?

[JV69z/28]

Sorry pour choise of words. Some people call it the "money stance". I was just refering to more than the normal 2" drop provided by lowering springs. By the tire and wheel sizes I was getting at it's a fact the dropped spindles limit the front wheel back space - did the narrowed control arms allow the use of 8" wide wheels with less back space? Those performance numbers seem really good - are the tires where most of the gain is coming from? I'm not trying to hi-jack the thread just trying to better understand where the improvements are coming from. The bottom line is when you guys at PHR do an article you finish reading with answers - these articles leave you with more questions than answers. Thanks again.

[Van B]

There is NO such thing as a 125 foot skidpad.. it's 200 feet...

Am I wrong, or is a skidpad not much more than a circle drawn on a flat piece of paved surface? Therefore it could be any size you wanted it to be. While 200 ft may be the standard, does it mean a smaller or larger one cannot exist?

[XcYZ]

Jeff, you're right. Lateral-g can be calculated. :lateral:

Lateral g = 1.22 * radius of track / (lap time * lap time)

EDIT: I don't know where the 1.22 factor comes from, maybe someone could explain that to me. Dennis?

[Steve1968LS2]

Am I wrong, or is a skidpad not much more than a circle drawn on a flat piece of paved surface? Therefore it could be any size you wanted it to be. While 200 ft may be the standard, does it mean a smaller or larger one cannot exist?

Sure.. you could have a 900ft skidpad if you want. Just plug into the formula. But I have never seen or heard of someone doing a 125 ft one.. heck, the 200ft one us and others use is pretty darn tight. At some point it just becomes a donut.. lol

That doesn't change the fact that the numbers through the cones is all wacked..

The skidpad results seem on track with a car running those types of tires, I had just never heard of a 125ft skidpad.. anyways, that's not really the point of contention.

[Steve1968LS2]

Jeff, you're right. Lateral-g can be calculated. :lateral:

Lateral g = 1.22 * radius of track / (lap time * lap time)

EDIT: I don't know where the 1.22 factor comes from, maybe someone could explain that to me. Dennis?


There becomes a point where it doesn't work though.. for example you couldn't have a 50 ft skidpad.. or one that is 3000 ft.. Maybe it was a 125ft skidpad. When I first made my mention that there is no such thing I thought the testing was done by Super Chevy and in that case there is no such thing. If some outside group or person did the testing then who knows what they used.

Still, the car did not go through 420 ft of cones spaced 70 feet apart at 58mph modified and 55mph with leaf springs.. no way.. no how.. :shrug:

[sinned]

Let me start by answering Scotts question about why use 1.22 as the constant in calculating lateral g forces. 1.22 is the simplified version of the real equation which should read: lateral acceleration = (2.0 x pi) squared X radius/time squared, and to find the force measured in “g” the value of 1G is plugged in using 32.174 (1.0G in feet per second per second is 32.174). When those numbers are plugged in the result is 1.2270286, rounded down to 1.227 (I am not sure who decided it should round to 1.22 rather than 1.23).

That said, using max lateral g as a measure of a vehicle performance capability is a marketing ploy used primarily by manufactures to show their vehicles performance. In reality very little about the 200 ft skid pad test relates to real world handling. The skid pad is a very controlled environment in which the vehicle is driven at its maximum speed while still maintaining its line within the circle. There is no braking, dive, acceleration, elevation change, direction change, or any other variable involved. A true test of a vehicle performance as it relates to handling can only be done on a technical road course where all of these variables are negotiated. Obviously if the driver is not a constant than the results as to how much of the ability is the vehicle and how much is the driver now come into play.

The 480ft slalom is more of a handling test than skid pad ever will be but still is plagued with the same lack of variables. I would like to see the SAE change its venue for performance testing to use a closed track that all manufactures must use when placing claim about vehicle performance as it related to handling capability.

[Steve1968LS2]

The 480ft slalom is more of a handling test than skid pad ever will be but still is plagued with the same lack of variables. I would like to see the SAE change its venue for performance testing to use a closed track that all manufactures must use when placing claim about vehicle performance as it related to handling capability.

Where would this track be located that all mfgs would have to truck their cars to?

Then of couse you would have to use the same drivers and make sure you have the same weather conditions.. lots of variables and it's another one of those "sounds good on paper" deals that really isn't practicle in real life.

Lets say the track is in Texas.. you truck the car there for the before.. truck it back to the shop in xyz.. do the mods then truck the car to Texas for the after and truck it home.. opps.. its raining so you do it again next week.. lol

These tests when done right are good for comparison and show a range of improvements (or not).. The track test would be the best, but it's just not practical unless you have hugely deep pockets.

[sinned]

These tests when done right are good for comparison and show a range of improvements (or not).. The track test would be the best, but it's just not practical unless you have hugely deep pockets.
I'm pretty sure most auto manufactures have deep enough pockets to handle this; they already spend millions on each platform during development. I agree that the driver variable will always be in issue, isn’t an issue with the skid pad and slalom as well? As for atmospheric variables, maybe on a drag strip or during 60-0 testing but on a 3 mile road course I really don’t think the difference between 60* and over cast vs. 80* clear skies are going to have a dramatic impact on the overall lap speed.

Although skid pad and slalom tests can be used to show improvement its not a realistic measure, you are only at testing solid state cruise speeds and there no significant direction changes in either tests (I left out the obvious variables that had already been discussed from the "lack of" list).

[Mean 69]

No big disagreement, Denny, but the last I looked, there were maybe a handful of cars that any of the manufacturers (and the list of cars gets REALLY thin with the big three alone) really care to think about road course/overall performance handling. There's a couple in Italy, a few in Germany, one really kick butt one in Sweden (of all places!!!), bla, bla.

And of course, just think of the liability!!!! One of the big three's lawyers actually endorsing performance/high speed driving! E-ghads! Good thought tough.

One note on the skid pad diameters. Theoretically, you'd expect slightly different numbers for lateral acceleration on different sized skid pads, but in practical terms, you'd probably never measure it. One biggie is steering input, and resultant slip angles of the tires. Ackerman, slip angles, boring book-crap like that. At some point, you have to come up with something practical, and I agree that the method that PHR and Primedia (out here anyway) do this stuff is a good overall compromise between a level playing field, good primary indicator, and safety for the cars and test drivers. Nothing's perfect. Unfortunately.

M

[Steve1968LS2]

I'm pretty sure most auto manufactures have deep enough pockets to handle this; they already spend millions on each platform during development. I agree that the driver variable will always be in issue, isn’t an issue with the skid pad and slalom as well? As for atmospheric variables, maybe on a drag strip or during 60-0 testing but on a 3 mile road course I really don’t think the difference between 60* and over cast vs. 80* clear skies are going to have a dramatic impact on the overall lap speed.

Although skid pad and slalom tests can be used to show improvement its not a realistic measure, you are only at testing solid state cruise speeds and there no significant direction changes in either tests (I left out the obvious variables that had already been discussed from the "lack of" list).

Well we use the same wheelman for our tests.. but yea. It's just that with a longer course the variables stack up more..

And while auto manufacturers have super deep pockets we are not discussing that here. We are talking aftermarket parts mfgs who in some cases are very small to medium sized companies. It would not make economic sense for these guys to ship test mules to a centralized location, so they do what they can.

We are sorta getting off topic here.. I think we could agree that while the 4 tests (slalom, skidpad, braking, 1/4 mile) are not the absolute best real world test of a car they are certainly a good guage if a part made improvements to a car and are valuable when done using correct scientific methods..

[Mean 69]

I bet they used a 480 slalom, I think that is the larger size that is frequently used? If so, ask Carl C how fast he did the cones several years ago in his leaf sprung car on a 480 slalom.

In everyone's defense on this though, my guess is that there is a whole lot left in DSE's test mule, it just needs sorting. I bet if you optimized the car overall for one performance benefit, it could do really well. Still, there doesn't appear to be "magic" in the setup even though the drama of comparitive numbers in the magazine would suggest it. Unless you know what other cars are capable of, it is hard to draw an absolute conclusion. Which, of course, is typical in competition for all of this stuff.

Mark

[Steve1968LS2]

I bet they used a 480 slalom, I think that is the larger size that is frequently used? If so, ask Carl C how fast he did the cones several years ago in his leaf sprung car on a 480 slalom.

In everyone's defense on this though, my guess is that there is a whole lot left in DSE's test mule, it just needs sorting. I bet if you optimized the car overall for one performance benefit, it could do really well. Still, there doesn't appear to be "magic" in the setup even though the drama of comparitive numbers in the magazine would suggest it. Unless you know what other cars are capable of, it is hard to draw an absolute conclusion. Which, of course, is typical in competition for all of this stuff.

Mark

I don't think so.. most everyone uses the 420/70 deal except Motor Trend and such who uses 600 foot I think.. then again they are always testing modern cars.

The SC story even said it was 420 foot with 70 foot seperation.

[Steve1968LS2]

Ok.. I had a nice long talk with Kyle at DSE.. here is the jist of it..

DSE did test through a 420 foot set of cones and they were 70 ft apart (like us out west). I sounds like they tried to replicate conditions as closely as possible, even going through the expense of getting new tires for the second test so the comparo would be fair (had new tires in the first test).

The only realy difference is in how we both optain our data. DSE used a VBOX data logging system that employs GPS and lateral accelerometers to determine speed. This is the same sort of system used by companies like GM and I think maybe even Motor Trend. They used the EXACT same spot to test with the cones in the exact same spots.

We use a set of timing lights. A car trips the first light going in and the second set going out. the distance between the lights is 420 feet and there are cones 70 ft apart. This system is widely used in racing and in events like autocross. We test in the exact same spot and we have spray painted marks so the cones and lights are in the exact same spot.

So what does this mean? Hell if I know, but I do belive that DSE was honest in reporting what they came up with and Kyle was very adamant that he stands by his number and would run the car again for any doubters. I've know DSE longer than I've worked here and have zero reason to doubt thier integrity.

Even if there was some flaw with thier equipment the testing would still be consistant and show an almost 3mph gain in the cones. That is a huge gain for such a short distance. When we tested the air ride stuff we got a .4 mph gain and we were happy. A 3mph gain is huge.

I think we just have to chalk up the differences to how the data was obtained (scientific methodology)..

Their skidpad numbers seem dead on given the tires they were running and I confirmed that a 125ft skidpad is quite possible although they most likely could have done bigger with a larger radius. They ran 125 ft since that's all the room they had a Maxton (it's a converted airport)

So, no drama.. just a difference in testing methods. I was very satisfied with Kyles explanation and I know that if he wasn't 2400 miles away he would be happy to run his car through our testing equipment and that shows a LOT.

[sinned]

I still have a HUGE problem believing that simply swapping rear suspension systems netted a .9 gain in the 1/4 mile, that is a massive gain.

[Van B]

Sure.. you could have a 900ft skidpad if you want. Just plug into the formula. But I have never seen or heard of someone doing a 125 ft one.. heck, the 200ft one us and others use is pretty darn tight. At some point it just becomes a donut.. lol

That doesn't change the fact that the numbers through the cones is all wacked..

The skidpad results seem on track with a car running those types of tires, I had just never heard of a 125ft skidpad.. anyways, that's not really the point of contention.

Sorry Steve, the a**hole in me took over when I read that you said there is NO such thing... :D

I bought the Super Chevy issue because of the article and was reminded of why I never really liked that mag much. Just doesn't turn my crank for some reason.

[Steve1968LS2]

I still have a HUGE problem believing that simply swapping rear suspension systems netted a .9 gain in the 1/4 mile, that is a massive gain.

I have a hard time believing that Paris Hilton is considered a celebrity, but that doesn't make it any less true.. lol

You would have to know how bad the stock leaf deal was doing. It could have been wrapping up terrible..

[Steve1968LS2]

Sorry Steve, the a**hole in me took over when I read that you said there is NO such thing... :D

I bought the Super Chevy issue because of the article and was reminded of why I never really liked that mag much. Just doesn't turn my crank for some reason.

That's ok.. not my magazine.. lol

Nobody really does less than 200ft though.. it's really just making the testing harder on yourself. But, it that's all the room you have...

[sinned]

I don't know, lots of guys running in the 10.5 class are deep into the 9's with leaf springs and it takes about 60HP to gain a second in the 1/4. I'd have to actually see the before and after tests to believe that, its not one of those "difficult to believe" situations, its just not conceivable unless there was something very wrong with the original springs (which kind of goes back to our last discussion about making sure we are testing "good" OE parts instead of broken worn out parts to make the after results look better).

[Payton King]

The trap speed should be the same for both tests as that is dependent on HP, What was the trap?

[Mkelcy]

The trap speed should be the same for both tests as that is dependent on HP, What was the trap?

From Pro-Touring board:

The quarter mile stuff is hard to peg as well. Too many variables. No such thing as a 383 in 68. But the Leaf Spring to Quadra-Link data is apples to apples:

All other things equal:
Leaf Springs: 15.16 @ 98.62 mph
Quadra-Link: 14.28 @ 101.22 mph

Lemme see.......That's damn near a second with no engine changes.
__________________
Steve Chryssos

[Steve1968LS2]

The trap speed should be the same for both tests as that is dependent on HP, What was the trap?

Well it should be within a few miles (2-4), especially since it was on different days. My 2000 SS ran anywhere from 102 to 107 depending..

[Alcino]

Don't you hate when there is the same topic in two forums ( here vs. p-t)

[Stuart Adams]

No not really.

[Steve1968LS2]

Don't you hate when there is the same topic in two forums ( here vs. p-t)

I've had the same topic in 4 diff forums at once.. just involves more cutting and pasting. :)

Readers Digest Version: the 58mph used in the DSE story is the exit speed of the car and not the average speed that we use in our normal testing.

The did it the same both times so the gain is still the gain.

Page 48 shows the data sets for the tests, but it's a bit hard to interpret. In future testing I am sure Kyle will test for average speed along with exit speed.

The VBOX stuff is uber accurate. I spoke with the head guy there and I am impressed with how it works and who uses this technology.

[rwhite692]

....The VBOX stuff is uber accurate....

Oh no...the beginning of the end...The "U" word being used on Lateral-G...

(Just funnin' with ya, Steve...) :)

[David Pozzi]

While the article says it is a test of the DSE rear suspension, the way I read the article it's comparing a stock suspension F/R to a complete DSE F/R suspension system, not just rear suspensions only. The tires/Wheels stayed the same. The first article was not very clear on what was done, but photos show stock springs as the "before" pics.

I agree measuring the top speed exiting the course is not as good a comparison as average speed through the course. Most airports have concrete surface which usually has better traction than asphalt, but often it is sloped in areas for dranage so a complex course would not be totally flat if it is a parking area. I'd imagine a runway or taxiway would be much flatter. I ran SCCA nationals at Salina KS, the course was in an aircraft parking area and it had flat and sloped areas, all concrete.

Steve,
Is this right? your test course is 420 ft, uses 6 cones spaced 70 ft apart, the timing lights are at the end cones?