Someone willing to do a little testing??

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#1 Fri, 04/12/2013 - 12:34
BMWENTHUSIAST's picture
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Someone willing to do a little testing??

I would like to find someone willing to do a bit of testing with a few tunes. Some of my tunes seem really good, but it would be nice to get some feedback from others. Someone willing to really give each tune a go before even looking at settings. This way you don't form opinions about what the car might/should do because of it's settings.

A couple reasons for this:

1. I'm curious if I'm tuning my cars to make them feel a certain way, which is working around something I'm doing wrong (whatever that is)

2. I'm curious if my tunes are helping, or holding me back.

 

Ideally I'd get some really specific feedback. Corner entry, exit, transitions (esses), and whatever other specific feedback you are willing to give.

 

If anyone is interested let me know. The cars include

S-Class

Masarati MC GT4

A-Class

95 MR2

C3 ZR1 Vette

E36 M3

Z4 Coupe

Z3 Coupe

95 Mustang Cobra R

E46 M3

BMW M635i

 

B-Class

Ford RS1800

BMW 2002

 

 

Fri, 04/12/2013 - 14:12
GRD 4 3L's picture
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I'll be your huckleberry . . . 

I'm comfortable with A-class or lower cars.  I use Catalunya National (for general handling) and Infineon (for suspension compliance) for my testing.

If you upload the tunes into your SF, I can download then test.  That way I cannot look at the tune settings.

Send me a FR to GRD_4_3L, _ is a space.

Fri, 04/12/2013 - 14:57
PTR_Paparazzi's picture
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Send me the first car you want feedback on.

I'll do a completely blind run, make some notes.

Then I'll check the actual build, and suggest any changes that would be helpful.

I can re-tune the car and send it back for you to try.  The only thing about the tune you should need to tweak would be how tight it is, and your brake bias.

Fri, 04/12/2013 - 17:51
BMWENTHUSIAST's picture
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OK I posted all but the Z4 Coupe on my storefront.

 

I'll get it up, and Pop I'll send one over later this evening.

Fri, 04/12/2013 - 22:18 (Reply to #4)
GRD 4 3L's picture
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I work slow so it may take few days per car.  Unless you have a priority, I'll start with a random car.  Like I said, I'll provide feedback for Catalunya National and Infineon IRL tracks.  If you would like to have it tested elsewhere, let me know quick.  You should select a baseline track so you can compare/rate all of your cars on that track.

Inputs = Tunes purchased through SF of "Prebuiltabyss93"

Outputs = Hard braking feel & balance.  Corner entry.  Mid corner deviations.  Corner exit.  Switchback response.  Front-rear grip balance.  Tire temperatures & pressures.  Ride stiffness.  Gearing.  Cold tire performance.  Warm tire performance. etc.

Fri, 04/12/2013 - 20:48
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I'm just going to say "good" and "bad" :P

Fri, 04/12/2013 - 22:21
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Initial Test Assessment:

Car:  '95 Toyota MR2

Catalunya National:  1:19.x

Infineon IRL:  1:40.5

This is a very responsive car but on the edge.  I do not have to fight with the car but I am lacking confidence to put the power down at corner exits as well as high speed sweepers.  

Catalunya National

1R:  End of straight (slightly downhill) braking and turn in was excellent.  The car naturally yaws into the turn which was nice.  However, the brakes were sensitive and required very gentle application.

2L:  Lift off turn in was very good but upon power application, the car slides to the right side towards the sand.

3R:  If I lift then the car understeers but careful throttle application keeps the car on track.  Lacking confidence to really attack this critical corner.

4R/5L:  Through this chicane the switch back response is good however the during the cornering transition the car feels like it is springing from one side to the other.

6L-Hairpin:  Again, the turn in is good (downhill) but exit throttle application has to be conservative.

7L:  The car does not feel settled for 8R.

8R-Carrousel:  understeers at lift off but oversteers with throttle

9R:  This corner feels good and the car turns into the corner well with trail braking

10L/11R:  Through the chicane, similar feel as the 4R/5L chicane; the car does not feel settled.

12R:  OK but have to watch the throttle

Infineon IRL

I'll be more general here.  The total suspension movement is only 1.07" and the car bottomed out at every valley (I think at 6 instances).  Braking had to be gentle (the car is very light) and power application also had to be restrained.  Driving over a high bump lifted one side of the car by about 15~20 degrees.  Turns in well when going downhill but understeers in flat or uphill turns.

The tire temperature range were excellent and the pressures were even.  Rear tires were slightly colder indicating front was doing too much work compared to the rear.

Summary:

Tire temperature & pressure balances were excellent.

Car responses to input were quick.

Car has understeering tendencies in corners.

Feels unsettled during switchack quick manouevers.

Cannot confidently put power down at corner exits and through long corners.

Driving over series of bumps is jarring and overly bouncy.

The suspension bottoms out on high vertical g tracks.

I'm going to give it few days then come back and retry it again.

Sat, 04/13/2013 - 21:59
PTR_Paparazzi's picture
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I tried the BMW E46 from the storefront. I'm on my phone now so can't go into heavy detail, but I will say the car is too firm. It is a very common mistake to keep your arb's up around 25 regardless of the build. This car is already extremely firm with a roll cage in it so when I retuned it my settings ended up at 9 front, 8.5 rear. With the same build, a retune gained me 1.1 seconds at Silverstone Int., and I'm very comfortable at that track as it's my home tuning track.
Sun, 04/14/2013 - 08:23
BMWENTHUSIAST's picture
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A few comments I should have made.

 

As I understand it the "fastest" theoritically diff settings are 100 on accell and 0 on decell. But this makes it really hard to drive. So, my diff settings are usually 75 accell and 25 decell and then I adapt the driving to match.

The odd thing is, the MR2 is set up so that with my driving I feel like I can just floor it out of most turns, and actually have to so that it holds the line I'm trying to take. If I don't the car is too tight and doesn't want to turn.

 

 

 

OK so at this point a few questions.

 

I set all of my cars as low as possible and usually pretty soft springs and damper settings. This will cause roll over (crash) issues when hitting curbs on some cars. But it seems like the car is faster everywhere else. This is more of a thought than a question I guess since GRD mentioned that the car was bottoming a bunch. (in fairness I didn't tune the MR2 for either track, or run it there for that matter-and I tried it after he did and it isn't very good there)

 

Pap, that is odd the car felt too firm. I normally have the springs and damper settings rather soft. With that said, I do usually have roll bars around 25, and 19-22 in the rear so you nailed that one LOL

I will give the much smaller anti-roll bars a try for sure.

I'll gift that tune over too so you can see exactly where everything was.

 

Sun, 04/14/2013 - 12:30 (Reply to #9)
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BMWENTHUSIAST wrote:

Pap, that is odd the car felt too firm. I normally have the springs and damper settings rather soft. With that said, I do usually have roll bars around 25, and 19-22 in the rear so you nailed that one LOL

I will give the much smaller anti-roll bars a try for sure.

I'll gift that tune over too so you can see exactly where everything was.

Yeah the firmness was specifically addressing the rollcage/arb combo.  Springs/Dampers could be perfect, but if your arb is too firm for the car then the car will skate in the corners.  Once the car starts to skate you can't apply any power to exit the corner.  You're constantly modulating to keep the car on the track.

Settings around 25 work in the cases where the car has no additional structural reinforcement.

At each stage of reinforcement (street, sport, race) I start by knocking off 5.0 points from the stiffness of the arb's.

Remember that if a car only has a race upgrade it's because it already has sport level reinforcement so starting your arb's somewhere in the range of 15.0 will get you closer to the finished numbers.

Sun, 04/14/2013 - 11:32
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"soft" spring is rather subjective since my soft would be very different from your soft.  I found the spring rates high, bump dampers too soft, and ride height did not match.  That's the reason for testing at 2 tracks; Catalunya for general handling characteristics and Infineon for suspension compliance.  For those occasions when I am off the racing line and have to ride the curbs, I would like to know that the car will not flip/tip (eg. Maple Valley chicane) or behave unexpectedly.

I am reminded of old F1 drivers (Jim Clark being my favourite) that set up their car then refrained from changing it other than the ride height & gears.  Those cars ran flat tracks such as Silverstone as well as hilly tracks like Mosport & Nordschleiffe and used same suspension settings.

You can certainly go the opposite way where you keep same ride height with changing suspension rates for different tracks but that's a lot of work and it's always a compromise of grip vs. responsiveness anyways.  Slightly high ride height is barely noticeable laptime wise but does wonders to predictability on any track that you take the car to.

Any specific track that you would like me to run on?

Sun, 04/14/2013 - 12:01
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I do all my testing on Road Atlanta.....I need to branch out I guess LOL

 

Mon, 04/15/2013 - 00:44
PTR_Paparazzi's picture
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Rebuilt, and re-tuned the e46 and gained another 0.7 s/lap around Silverstone Int.  Sent the new build over.

Mon, 04/15/2013 - 09:43
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I'll re-test the '95 MR2 at Road Atlanta for your/my reference.  Do you have a target time for '95 MR2 on this track for benchmark purpose?

Just so I can understand the nature of the car better, I built my own '95 MR2 as well and wil all that power on a light car made it difficult to tune (not an experienced MR tuner) but the exercise taught me several valuable lessons.  I do not like the look of stock T10 wings so I left them out which makes the drive little more challenging.

'95 MR2 is MR therefore front end weight is much lower than a typical FR.  Therefore spring rate, dampers, brake balance, and ARB strategy for FR did not work.  I made the oversight of putting in usual FR numbers/ratios and the car understeered and wobbled through chicanes.

I think the front weight distrib for '95 MR2 after the weight reduction + roll cage comes around to about 42%.  I am wondering if you have done the same as I have (putting in higher spring rate for the front compared to the rear)?

Once I made the correction the car turned in admirably, the unsettled wobble coming out of chicane was much reduced, and the exit oversteer was gentle enough to call it "fun".  I can feel the front end scrub a bit with a bit too much oversteer which I think are related and will be working on.  The car also is much faster on the straight since it has no wing; I would think removal of the wing would benefit greatly at high speed tracks such as Road Atlanta.  

Once I am happy with it I'll put it on my SF so you can give me your feedback.

So, BMW, do you remember (or can you check) if the car set-up was done as MR configuration (heavier rear) or a FR (heavier front)?  

This has been a great learning lesson for me.  Thank you for the opportunity, BMW.  The car has very good chassis and it is growing on me very quickly!

Mon, 04/15/2013 - 09:52
BMWENTHUSIAST's picture
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Mid 1 29's at RA in the MR2 is a good lap. For me anyway. 

Its definitely different than a fr car and it has more of what I call weight swing than some of the other MR cars IMO

 

I appreciate the feedback. I think it will make me faster for sure

Mon, 04/15/2013 - 10:35 (Reply to #15)
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BMWENTHUSIAST wrote:

more of what I call weight swing than some of the other MR cars IMO

Yes, noticed it at the high speed chicane at Catalunya National.

Tue, 04/16/2013 - 10:21
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BMW, I tested your tune at Road Atlanta last night and achieved 1:29 as baseline.  The car actually works very well on that track but the car is still hesitant to turn-in even with lift off.

First corner is challenge on every lap to slow the car down enough so the car turns in sufficiently to make the corner.

The chicane and the downhill esses also have to be taken with throttle control to stay on track.  The left hander at the end of esses also exhibits entry understeer.  Perhaps a little softer front ARB would be good?

Corner exits are fine but my preference is little more suspension compliance for driving over the curbs on this track.

This car is very light so braking (without locking up) has been very difficult using hand controller.

Mon, 04/22/2013 - 15:53
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A lot of testing for race series here and there.  I'll return to this exercise later.

Wed, 05/15/2013 - 18:55
BMWENTHUSIAST's picture
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I actually learned quite a bit from you guys.

 

 

Anyone care for another round of testing?

Tue, 05/21/2013 - 22:08 (Reply to #19)
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BMWENTHUSIAST wrote:

I actually learned quite a bit from you guys.

 

 

Anyone care for another round of testing?

yep, send over a tune.
Wed, 05/22/2013 - 07:17
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OK I will later tonight.

 

 

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