Home  |  Forums  |  914 Info  |  Blogs
 
914World.com - The fastest growing online 914 community!
 
Porsche, and the Porsche crest are registered trademarks of Dr. Ing. h.c. F. Porsche AG. This site is not affiliated with Porsche in any way.
Its only purpose is to provide an online forum for car enthusiasts. All other trademarks are property of their respective owners.
 

Welcome Guest ( Log In | Register )

 
Reply to this topicStart new topic
> Tire Pressures, Trackcross Tire Pressures
BENBRO02
post Dec 14 2019, 08:34 PM
Post #1


Member
**

Group: Members
Posts: 480
Joined: 6-March 15
From: Nokesville, Virginia
Member No.: 18,493
Region Association: MidAtlantic Region



My son and I are going to a track cross tomorrow at Summit Point. My son's BMW is not ready so I plan on driving my 914 and letting him drive my Acura. Please give me recommendations on tire pressures for the 914. I have never had it on a track. It has a stock suspension without sway bars, 205-55-15 tires (300 treadwear rating) on 4 lug Fuchs. It will only be 50 degrees.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Krieger
post Dec 15 2019, 12:08 AM
Post #2


Advanced Member
****

Group: Members
Posts: 4,685
Joined: 24-May 04
From: Santa Rosa CA
Member No.: 2,104
Region Association: None



I would use the stock recommended tire pressures. Set them 26 front, 29 rear in the am before you drive anywhere.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
BENBRO02
post Dec 15 2019, 10:22 AM
Post #3


Member
**

Group: Members
Posts: 480
Joined: 6-March 15
From: Nokesville, Virginia
Member No.: 18,493
Region Association: MidAtlantic Region



QUOTE(BENBRO02 @ Dec 14 2019, 09:34 PM) *

My son and I are going to a track cross tomorrow at Summit Point. My son's BMW is not ready so I plan on driving my 914 and letting him drive my Acura. Please give me recommendations on tire pressures for the 914. I have never had it on a track. It has a stock suspension without sway bars, 205-55-15 tires (300 treadwear rating) on 4 lug Fuchs. It will only be 50 degrees.

Thank you
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
infraredcalvin
post Dec 15 2019, 11:05 AM
Post #4


Distracted Member
***

Group: Members
Posts: 1,496
Joined: 25-August 08
From: Ladera Ranch, CA
Member No.: 9,463
Region Association: Southern California



Agree with stock.

Question is if you've ever been on the track? If not, or not much, concentrate on the course, your sight (looking ahead), shifting points, etc. have fun, don’t worry about that till you’re hooked and buying real tires....
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
BENBRO02
post Dec 15 2019, 09:05 PM
Post #5


Member
**

Group: Members
Posts: 480
Joined: 6-March 15
From: Nokesville, Virginia
Member No.: 18,493
Region Association: MidAtlantic Region



QUOTE(infraredcalvin @ Dec 15 2019, 12:05 PM) *

Agree with stock.

Question is if you've ever been on the track? If not, or not much, concentrate on the course, your sight (looking ahead), shifting points, etc. have fun, don’t worry about that till you’re hooked and buying real tires....


I've done 5 track days and was amazed at the lack of grip because of the cold weather. I ended up letting my son drive the 914 and I drove the Acura. It was a great father & son activity. We were in different classes but our afternoon times were only 0.038 second apart. 2 observations from my son. The 914 needs a front sway bar and a sport seat.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
infraredcalvin
post Dec 15 2019, 10:31 PM
Post #6


Distracted Member
***

Group: Members
Posts: 1,496
Joined: 25-August 08
From: Ladera Ranch, CA
Member No.: 9,463
Region Association: Southern California



I’ve got same sizes but with 460 tw tires on mine now, I feel your pain with lack of grip, doesn’t take much to warm them up, and they get greasy shortly thereafter. Finishing cleaning up some track wheels, then I’ll fit some 200 tw tires (trying to stay in certain class).

Did you take the seat bottom out of the 914 seat? Have a harness bar too? That might temporarily help the seat issue. I agree with sway bars, I run both front and rears among a bunch of other stuff, I just need to continue working on the driver.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
BENBRO02
post Dec 16 2019, 06:18 AM
Post #7


Member
**

Group: Members
Posts: 480
Joined: 6-March 15
From: Nokesville, Virginia
Member No.: 18,493
Region Association: MidAtlantic Region



QUOTE(infraredcalvin @ Dec 15 2019, 11:31 PM) *

I’ve got same sizes but with 460 tw tires on mine now, I feel your pain with lack of grip, doesn’t take much to warm them up, and they get greasy shortly thereafter. Finishing cleaning up some track wheels, then I’ll fit some 200 tw tires (trying to stay in certain class).

Did you take the seat bottom out of the 914 seat? Have a harness bar too? That might temporarily help the seat issue. I agree with sway bars, I run both front and rears among a bunch of other stuff, I just need to continue working on the driver.

Taking the seat bottom out is a good idea, my son is 6'2" so we took the top off so the helmet wouldn't hit. Thanks for the tip.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
wndsrfr
post Dec 16 2019, 11:04 AM
Post #8


Senior Member
***

Group: Members
Posts: 1,427
Joined: 30-April 09
From: Rescue, Virginia
Member No.: 10,318
Region Association: MidAtlantic Region



Bottom seat cushion out, use a 1/2 inch foam pad. Highly recommend Bridgestone RE71 tires when you start looking...I just ran them at Roebling... got the same lap times as I did with Hoosiers, surprised me. Get them shaved to 4/32 from Tire Rack...
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
Racer
post Dec 16 2019, 01:09 PM
Post #9


Senior Member
***

Group: Members
Posts: 787
Joined: 25-August 03
From: Northern Virginia
Member No.: 1,073
Region Association: MidAtlantic Region



bottom cushion removal is a longtime trick. Without foam though, you get to sit on fiberglass. Trade off is slightly more bolstering and head room.

I find that my left knee often ends up locking the drivers door by the end of my run. Likely part of my trying to brace myself.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
RARE 6
post Dec 16 2019, 01:55 PM
Post #10


Member
**

Group: Members
Posts: 141
Joined: 18-January 15
From: Grand Junction CO
Member No.: 18,337
Region Association: Rocky Mountains



QUOTE(infraredcalvin @ Dec 15 2019, 09:05 AM) *

Agree with stock.

Question is if you've ever been on the track? If not, or not much, concentrate on the course, your sight (looking ahead), shifting points, etc. have fun, don’t worry about that till you’re hooked and buying real tires....


Sound advice, though it sounds like you're now hooked. Line, braking points, apexes etc. all are more important and will shave lap times whatever tires you used. Fastest time I ever turned at Woody Creek in the -6 back when we were consistently posting top class times in PCA DE events was on used Dayton Thoroughbred street tires pulled off a Ford Torino because we were dead broke at the time. Came close with all the other back in the day cool tires (XWX, Pirelli, BFG Comp TAs, etc) but apparently had all those other driver elements dialed in with the Daytons that particular afternoon.
Get a front sway bar and some lower springs in the back. Those will make a huge difference. Now that you're hooked, remember that the last few hundreths of a second off your lap times will be exponentially more expensive than the first few full seconds.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
wndsrfr
post Dec 19 2019, 10:10 AM
Post #11


Senior Member
***

Group: Members
Posts: 1,427
Joined: 30-April 09
From: Rescue, Virginia
Member No.: 10,318
Region Association: MidAtlantic Region



Saw your pic that you posted in the Paddock area... post it here also and you'll get more recommendations really nice action pic.
Think about a front sway bar... your son has the driver's side completely unloaded.... nice.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
914Toy
post Dec 19 2019, 11:17 AM
Post #12


Senior Member
***

Group: Members
Posts: 710
Joined: 12-November 17
From: Laguna beach
Member No.: 21,596
Region Association: Southern California



Many of my track colleagues used to aim for hot tire pressure to be at 34 lbs pressure, starting with 28 lbs (ambient around 80 degrees) cold tire pressure - trial and error adjustments to final preferred hot temp.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
infraredcalvin
post Dec 19 2019, 12:19 PM
Post #13


Distracted Member
***

Group: Members
Posts: 1,496
Joined: 25-August 08
From: Ladera Ranch, CA
Member No.: 9,463
Region Association: Southern California



A simple approach to begin with is to make sure you’re using the entire tread. Tires have several markers on the edge (usually little triangles). The wear area from your session should touch the point of the triangle. Mark a line with chalk across the corner of the tire edge to more easily see the wear area from the most recent session. If the chalk is worn off at the tip of the arrow, you’re close to the right pressures.
User is offlineProfile CardPM
Go to the top of the page
+Quote Post
BENBRO02
post Dec 19 2019, 01:05 PM
Post #14


Member
**

Group: Members
Posts: 480
Joined: 6-March 15
From: Nokesville, Virginia
Member No.: 18,493
Region Association: MidAtlantic Region



Here's the picture of my son at speed.


Attached thumbnail(s)
Attached Image
User is offlineProfile CardPM
Go to the top of the page
+Quote Post

Reply to this topicStart new topic
1 User(s) are reading this topic (1 Guests and 0 Anonymous Users)
0 Members:

 



- Lo-Fi Version Time is now: 28th March 2024 - 12:45 PM