Super Chevy and DSE Test

[harshman]

here it is


I'm swapping to an ls1/r compound/air bar/hydroboost/more stiffer/more times my faster....you get the idea. all in hopes to get a new shoot - Johnny's camaro pissed me off - stock '96 z28 w/nitto's and it riped my car a new one.

If you couldn't tell, I've got the bug badly.

[Steve1968LS2]

That's right!! Your car was tested, wasn't it? No, I checked, no typo. Can you post numbers for your car? I don't know if your course was comparable.
The slalom in this test was 420 feet 70 feet apart. The Skidpad was only 125 feet in diameter. I don't see enough data in the article to fill in the blanks.

I need to check into this.. that seem impossibly fast for the nomal cone setup we use.. for reference Alcino's car ran 48mph I think and at the time that was the fastest car ever tested..

I will check on monday what it was. Also, we generally use a 200ft skidpat.. 125 feet is pretty damn small..

[Nutsy]

I need to check into this.. that seem impossibly fast for the nomal cone setup we use.. for reference Alcino's car ran 48mph I think and at the time that was the fastest car ever tested..

I will check on monday what it was. Also, we generally use a 200ft skidpat.. 125 feet is pretty damn small..

Any updates on this Steve?

[woody80z28]

Didn't the G/28 only hit like .91g and 46mph on the Nitto R-compounds?

[Steve1968LS2]

Didn't the G/28 only hit like .91g and 46mph on the Nitto R-compounds?

I do believe g/28 did .94 in the 200ft skidpad and 46.48 in the cones..

[Steve1968LS2]

**Baseline numbers: About 41-42 mph on a 420 foot course.
DSE front and rear upgrades: 58.39 mph avg.

**I pulled the baseline numbers from another article in the same issue since the "front upgrades only" test (April issue) does not include factory stock numbers.

Rick, The leaf spring numbers were posted in the April issue and also serve as the before numbers in the may issue. 55.55mph avg and .81g. That's front suspension upgrades and wheels/tires only.

Uh.. the car did not run the cones at 58.39 mph.. no car ever has come close to that..

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

[Steve1968LS2]

That's right!! Your car was tested, wasn't it? No, I checked, no typo. Can you post numbers for your car? I don't know if your course was comparable.
The slalom in this test was 420 feet 70 feet apart. The Skidpad was only 125 feet in diameter. I don't see enough data in the article to fill in the blanks.

Yep, typo.. I haven't seen the Super Chevy story but if it says 58.xx then it's a typo.. I though you just made the typo.. lol.. am I in trouble now????

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?

I've never seen a 125ft skidpad, i guess it's possible but it seems like it would hurt your number.. we use 200 feet and that feels pretty tight. Still, .84 g seems like a reasonable number on the tires listed in the story (pilot sports).

Formulas:

420ft Slalom Equivilants

420/time = ft per sec x 3600 / 5280 = mph
------
200-ft Skidpad

g= 1.225 x radius (in feet) / time sq.

[nickdoe6]

Steve is correct. We tested a shifter kart that did a best of 58 MPH in the 420' slalom, so there is no possible way the numbers for that Camaro are correct.


Nick L

[96Z28SS]

What did the Art Morrison 55 chevy do for numbers? Did it have street tires on it?

I would've liked to see the Camaro beat the bigger 55 Chevy, but I can't remember what the number was it was above .9

[alcino]

It pulled a .94 skid and did the slalom in 5.92sec, from what Katz told me.

That computes to 48.37mph slalom!

and from what I recall it did not use R compound tire. Correct me if I'm wrong. Now thats amazing for such a huge car.

[Steve Chryssos]

.. lol.. am I in trouble now????

It's not your fault. Just call DSE and corroborate.

[TA219]

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.

That leaf spring set up must have been expierencing alot of axle wrap. I wonder what the 60" was.

[Steve1968LS2]

It pulled a .94 skid and did the slalom in 5.92sec, from what Katz told me.

That computes to 48.37mph slalom!

and from what I recall it did not use R compound tire. Correct me if I'm wrong. Now thats amazing for such a huge car.

Yes, the Art Morrison car did very well.. I do not think any car has managed to hit 49mph..

[Steve1968LS2]

It's not your fault. Just call DSE and corroborate.

I will... but it's a fact that those cone numbers are very different from ours.. It's like posting that someone ran the mile in 1 minute.. lol

The main question would be how did they time everything. lights? Stopwatch?

I have a feeling that whatever they did it was the same for both tests (before and after). So the fact that there was a huge gain is not in dispute. a 3mph gain is huge.

To be honest I really shouldn't be involved since it's not my magazine. I only need to make sure this is clear since is screws up all of our testing results. After all, if we talk up a car that did 48.x as super great, the people who read the DSE SC story would be like.. "that's a terrible number" since they would think 58mph is actually possible. make sense?

[69rs]

Go Columbo! Let us know what you find out!

[Rick Dorion]

To be honest I really shouldn't be involved since it's not my magazine. I only need to make sure this is clear since is screws up all of our testing results. After all, if we talk up a car that did 48.x as super great, the people who read the DSE SC story would be like.. "that's a terrible number" since they would think 58mph is actually possible. make sense?

Perhaps speak with your counterpart rather than get in the middle with DSE?

[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.

[Steve1968LS2]

Perhaps speak with your counterpart rather than get in the middle with DSE?

Terry Cole (editor of Super Chevy) is no longer working here.. and there is no "in the middle with DSE".. they want to get the facts out there as much as anyone. Kyles explanation made sense and I feel they carried out thier tests with integrity and the proper use of science. I don't know enough about the VBOX to discuss how it may vary from timing lights.

I think we should also give DSE credit for putting thier stuff to the test unlike many mfgs who just sell promises.

[alcino]

Oh I get it now. It’s like Einstein relative math. In the car(data acquisition) you are wiggling through cones at 58mph(more distance than 420'/time), but an observer watching from the side (entrance and exit lights) sees a car passing by at 48mph(420'/time). The only thing the same is the time elapsed from the entrance to the exit. Without it, it’s like comparing apples to oranges.

[Mkelcy]

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.

Steve: We appreciate your work in trying to understand the very different results between the PHR methodology and that used in the DSE tests. I don't understand why different methods of measuring the same test would result in a 20% or greater difference in test results UNLESS one of the two methodologies introduces error in the measurement.

Understanding why the DSE methodolgy gets markedly faster results than the PHR methodolgy is important, because depending on where and how the measurement variables are introduced, the repeatablity of one of the two methologies may be suspect.

LET ME BE VERY CLEAR, I'm not in any way suggesting DSE rigged the tests.

I'm not familiar with Vbox technology, but I wonder how the data acquisition is triggered (manually, in or out of the car; taken from a longer data set and edited down to the slalom run; externally triggered; other). If manually triggered an error of 0.10 seconds on entry and exit could account for 1.8 MPH of the difference. In addition, differential GPS technology is supposed to be accurate to within 1 to 3 meters. I don't know whether the error is consistent - that is whether the GPS receiver is always wrong by the same amount. If it is, this is not likely a source of error. If it's not, then this could also contribute one to two MPH of the difference. Finally I wonder if there was any run-in and run-out on the DSE slalom course. A brief burst of acceleration could also contribute a bit of speed.

If DSE were willing to do so, a back-to-back test using the Vbox technology and your fixed, autiomatically triggered timing lights might be a very interesting article.