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Fighting understeer - looking for ideas

Old 10-26-2018, 04:47 AM
  #31  
yoramw
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I have not thought about that.
Before I replace near new tires, would it be a wise idea to switch front and rear to see if the 8" up front changes it that much?

In any case, I have already changed the rear springs to 350lb, so I will go with that to the track on Tuesday and see the effect of that.
Maybe I will swap the R & F wheels mid day so that I can get a sense of that too.

BTW, tires are Hankook RS3 (Z222) identical on all 4 corners


Thanks!
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Old 10-26-2018, 09:19 AM
  #32  
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Recommended wheel for 225/ tire is 6-8".

That said, same wheel/same tire F/R is better.

T
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Old 10-30-2018, 09:42 AM
  #33  
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Quick update:

Did my track day today and the car handles much much better.
I started without any changes other than the rear springs. The car felt already faster, but was a bit too playful...
I then closed a few clicks in the front coil overs (I had to open it completely on my prior track day) and the car felt natural allowing to tighten corners with lift offs and accelerate on the long sweepers.

I am quite happy with the change, but I am still thinking about what Kev951 said about the 7 vs 8 wheel I have with square 225 tire setup.
Since it is not easy to locate Porsche 16x8 with early offset in my neck of the woods, I have two easy options:
1. Leave it as is, perhaps getting new tires with stronger sidewalls
2. Move back to 205.55 on the 7" front wheels

I am on the hunt for a pair of 16x8 et23 phone dials, so if anyone have such for sale, let me know (true and straight, but cosmetic condition is lesser importance).
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Old 10-30-2018, 11:43 PM
  #34  
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16x8 phone dials are going to be hard to find. I have been looking FOREVER. I did find a pair three years ago and I said "I'll just get them later somewhere else." Big mistake that was.
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Old 11-01-2018, 11:05 AM
  #35  
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I have a pair of early offset 16x8 phone dials I'd be willing to sell for $400 plus shipping without tires.
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Old 11-02-2018, 06:06 AM
  #36  
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Thanks.
I just replied to you pm.
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Old 11-02-2018, 06:10 AM
  #37  
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BTW,
Here is a practice lap with the new setup at Arad.
This is in preparation for a time atack event. They changed the layout to be super technical, short and almost no straights.
Some of the turns are tricky as they went the opposite direction to how the track was designed for:

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Old 11-02-2018, 04:35 PM
  #38  
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Old 11-02-2018, 10:04 PM
  #39  
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Originally Posted by yoramw View Post
Quick update:

Did my track day today and the car handles much much better.
I started without any changes other than the rear springs. The car felt already faster, but was a bit too playful...


I am on the hunt for a pair of 16x8 et23 phone dials, so if anyone have such for sale, let me know (true and straight, but cosmetic condition is lesser importance).
Congrats on the improvement, the wheels is another step in the right direction.

T
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Old 11-03-2018, 02:18 AM
  #40  
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It's still holding you back (the understeer) as you can hear the front scrubbing pretty early in most corners. Haven't read this whole thread but to me it's probably a combination of causes.
One of the best things I did was to go to a larger footprint / square setup and get some decent rubber. That might mask some other causes and you still have to dial in the suspension geometry correctly, but 10"x18" with 275's all round wasn't too excessive nor expensive to buy.

We did find that in some slower corners we got some front wash but that was due to going into bumpstops and running out of travel. Fixed this by changing to Racers Edge camber plates that were a better design.
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Old 11-04-2018, 12:25 AM
  #41  
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Originally Posted by 333pg333 View Post
It's still holding you back (the understeer) as you can hear the front scrubbing pretty early in most corners. Haven't read this whole thread but to me it's probably a combination of causes.
One of the best things I did was to go to a larger footprint / square setup and get some decent rubber. That might mask some other causes and you still have to dial in the suspension geometry correctly, but 10"x18" with 275's all round wasn't too excessive nor expensive to buy.

We did find that in some slower corners we got some front wash but that was due to going into bumpstops and running out of travel. Fixed this by changing to Racers Edge camber plates that were a better design.
Trouble is Patrick (acknowledging you haven't read thread), his tracks are very short and tight, the 18's will kill his gearing.

T
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Old 11-04-2018, 01:27 AM
  #42  
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Rolling radius is virtually the same with 18's via much lower profile rubber though? Sure they'll weigh a little more but I'd take a few lbs for the extra footprint plus you can generally get a better tyre the larger you go.
You do have to pay to play though.
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Old 11-04-2018, 12:27 PM
  #43  
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Thanks for the inputs.
I am running square 225/50/16 (still with 7" front wheels)
I guess some of the understeer could be attributed to driving experience too. I am try to trail brake on many of the corners, but I am not very experienced with it yet.
I was considering moving to 17 wheel (245 or 255), but was not sure how big of and impact it will have (I do not need to upgrade my brakes, stock are doing fine with our tracks here).
May engine is fairly stock, so I assume putting too big wheels will take its toll power wise.

BTW, my first race was yesterday, I was able to shave 1.3 seconds from the practice session last week. It was good for the "Old School" category we have, but comparing my time to a modern chipped MX5 ND with upgraded race suspension,I am still almost 4 seconds away which is huge (I assume part is driver, but surely part is car)




Last edited by yoramw; 11-04-2018 at 12:50 PM.
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Old 11-04-2018, 12:41 PM
  #44  
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Looking on multiple options to continue improving my lap time:

Car related:
1. I have VEMS and fuel delivery upgrade waiting in the closet for install
2. I received an Audi V8 LSD (torsen) for little money and I hope to swap my open diff with it (I did it for a friend with an NA already so I know what needs to be done other than the trans oil cooler).
3. Continue to stiffen the rear (currently with 350lb, 8 clicks dialed in the coil overs)
4. Swap wheels for wider and larger 17"

#1 & #3 are easy
#2 & #4 doable, but will take more time

Driver related:
1. Watch my videos over and over... (doing it already)
2. Get more time with an instructor on the track
3. Get some driving simulator lessons - we have a top notch simulator instructor here and I am quite a numbers guy, so the telemetry I get there is also quite helpful

Obviously I can't do all for the two races I have in the coming weeks, so I want to zoom in two or three items first.
What would you recommended?

Thanks so much for your help so far.
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Old 11-05-2018, 05:26 AM
  #45  
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Could be a few things. Suspension geometry, tyres, size of tyres, tyre pressure. Pushing the car beyond it's mechanical grip will also do it but the tyre noise seems to start pretty early into the turn entry which to me seems like it could be a combination of causes.
Certainly getting an instructor will help. Especially if he/she knows a thing or two about setup. Congrats on having fun though!
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