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View Full Version : what to do with $4500.00


dcramer
03-30-2012, 10:38 AM
Choice 1: S54
Choice 2: rebuild S52 and put some goodies on it like cam/hfm/software
Choice 3: use the money for track days

cormier
03-30-2012, 10:43 AM
S54 dooooo itttttt

craz azn
03-30-2012, 10:46 AM
Money for track days. Did you ever end up getting a roll bar and race seats installed?

dcramer
03-30-2012, 10:52 AM
Rudy,

Well the seats, yes. The roll bar was a bit of a SNAFU. Ended up ordering a bolt in from bimmerworld. Local guy wanted way too much for it

T.Dot_E30
03-30-2012, 11:06 AM
How much track experience do you have? If very little or not much, i'd say do that first before more modding.

If you think your driving is not the one holding the car back, then I'd do Cams/3.5 Maf/software assuming your suspension is all setup.

Save your money, just enjoy it, do maintenance and wait till something breaks...

El Gato Liso
03-30-2012, 12:09 PM
s54 so i can have your s52

T.Dot_E30
03-30-2012, 01:57 PM
s54 so i can have your s52

I doubt he will sell you it to you for $250.

cormier
03-30-2012, 02:27 PM
If you get it for 250, I'll buy it off you for like.... 275 :p

What do you want out of your car? You need more power? Want another project? Want more track / instruction time? Suspension? Maintainance?

dble Trouble
03-30-2012, 10:06 PM
Track days and performance driving schools.........More Mods come after you can drive the wheels off of the car!

doogee
03-30-2012, 10:16 PM
Choice 3.

richie_s999
03-31-2012, 07:26 AM
Choice 3, but rent a track for the day and invite all of us!

dcramer
03-31-2012, 07:57 AM
yes, I am leaning towards choice 3.

davericher20
03-31-2012, 03:32 PM
Choice 3, but rent a track for the day and invite all of us!

This

careless7
03-31-2012, 04:54 PM
R-Comps and go to track, your car is quicker than you think.

dcramer
03-31-2012, 05:44 PM
I think winter is just too long around here. Sitting around waiting for track days reading about other people swapping engines is too enticing

I've decided to go to the track with it.

dble Trouble
04-01-2012, 01:52 AM
Without proper experience or instruction first, I would not recommend R compounds. Depends on your driving resume.

dcramer
04-01-2012, 07:49 AM
^^^ Why is that ? I drove on R-comps pretty much right away 2nd time out I think.

davericher20
04-01-2012, 01:04 PM
because the limit is much higher with those tires, with inexperience they could be very unforgiving. Gradually increasing the compound (starting with high performance street tire) is the best way to go.

dble Trouble
04-01-2012, 02:15 PM
^^^ Why is that ? I drove on R-comps pretty much right away 2nd time out I think.


It's a typical rookie thing to do. I was going to say mistake, but it all depends on the way you look at it. From an instructor, and safety point of view, it is a mistake. As Dave mentioned, the limits are much higher, but most R comps don't squeal at the limit they just give away, if you're not experienced controlling or regaining control may be difficult or not possible. Also, there is less feedback from the tires as you approach the limit. Another reason is, when learning, you should be able to drive the wheels off of the car with street tires before you move to 'r' comps. By doing this you learn at a more modest speed and learn more car control skills.

If your sole objective is to go fast and forget learning well then use 'r's right away and chance it. But you won't learn nearly as well or as quick than if you had good street tires.

Gleb
04-02-2012, 02:31 AM
Choice 1: S54
Choice 2: rebuild S52 and put some goodies on it like cam/hfm/software
Choice 3: use the money for track days

I say definitely NUMBER 1


....... just because I dare you to pull it of for $4500!

dcramer
04-02-2012, 12:12 PM
Without proper experience or instruction first, I would not recommend R compounds. Depends on your driving resume.

So what would constitute "proper instruction" ? I've been to the trillium ADS a few times and was not given any specific instructions related to this at all.

cormier
04-02-2012, 03:13 PM
I think he just meant instruction to the point that you're comfortable with the limits of your street tires-- knowing when traction will be lost, how it feels and what to do so that when it happens faster on the r-comps, it won't be a surprise

dcramer
04-02-2012, 04:10 PM
I'm curious about "happens faster" ? I would think that because you can go faster that it would happen at a higher speed. My experience suggests that when R-comps do let go they are much more controllable and recoverable.

One thing that I was surprised about was on a the cool down lap they do some very strange things over the cement at mosport due to the difference in grip between cement and pavement.

None of my instructors mentioned this before it happened.

dble Trouble
04-02-2012, 11:16 PM
I'm curious about "happens faster" ? I would think that because you can go faster that it would happen at a higher speed. My experience suggests that when R-comps do let go they are much more controllable and recoverable.

One thing that I was surprised about was on a the cool down lap they do some very strange things over the cement at mosport due to the difference in grip between cement and pavement.

None of my instructors mentioned this before it happened.


The reason you didn't hear anything from the instructors is that it is not part of the curriculum to discuss the differences modifications make for C and B students. Of course if you ask your instructor they will answer you. There are just too many other things to cover at that level. However in the A curriculum there are some discussions about some modifications from benefits to set ups etc.

R comps do not recover quicker. Once you've reached the liimit of adhesion with an R comp, they completely let go until you slow down enough that they regain their composure or you hit a wall! (lol) But seriously, it has happened. The only time in my driving career that I ever spun out was on R comps. Luckily for me all 4 tires stayed on the asphalt. It's like once you reach the limit your grip falls off a cliff hence the suddeness. Street tires are constantly howling at the track, but as you push harder, they scream louder and your senses ie your hearing tells you that you're reaching the limits amongst other things. Your car will also be less responsive at this point but still controllable until you push a little harder and then start to slide at which point its up to you to control what's happening.

Now once you're in a slide it's up to you to bring it back but since 1.) you are going slower with streets you can recover quicker, but also the nature of the rubber will start to regain composure more quickly 2.) R's will not give you the same type of warnings so to the amateur/rookie/intermediate driver you may not see the warning signs coming.....

R compounds are faster, and more durable at the track so yes I do recommend everyone to aspire to them, just don't start with them. One more thing I'd like to add, R compounds are very susceptible to tire temperatures. For example your 1st lap out on cold r compounds the will have LESS grip than any street tire. As they warm up the tire pressures alter drastically with air and moderately with nitrogen. Don't listen to anyone that tells you Nitrogen doesn't change tire pressures with temperature...IT DOES! Just not nearly as much as with air. As the rubber compound warms up it starts to give more grip altering the feel and approach to cornering including slip angles, speed, positioning etc. Also with the tire pressure get greater with the heat, that also affects the feel and approach to driving. There are so many more things that I can talk about in regards to this one topic but my fingers are getting tired from typing!!! I think you get the idea. Keep the questions coming though if you want more......

richie_s999
04-02-2012, 11:27 PM
If you were surprised by anything that happened with r-comps on your car you were not ready

Instructors teach technic, not car set up.

dcramer
04-03-2012, 06:58 AM
If you were surprised by anything that happened with r-comps on your car you were not ready

Instructors teach technic, not car set up.

How would you "prepare" yourself for the first time you experience a sudden change of grip across the cement patches at Mosport? It doesn't happen with street tires. The only way you can understand it is to experience it. It is also only becomes really noticeable when you are going slow.

As far as what the instructor teaches; the instructors have all asked me what tires I have, I would think if I were riding in a car with someone on r-comps I might mention it.

dcramer
04-03-2012, 07:18 AM
The reason you didn't hear anything from the instructors is that it is not part of the curriculum to discuss the differences modifications make for C and B students. Of course if you ask your instructor they will answer you. There are just too many other things to cover at that level. However in the A curriculum there are some discussions about some modifications from benefits to set ups etc.

I've never heard it at the A level either.


R comps do not recover quicker. Once you've reached the liimit of adhesion with an R comp, they completely let go until you slow down enough that they regain their composure or you hit a wall! (lol) But seriously, it has happened. The only time in my driving career that I ever spun out was on R comps. Luckily for me all 4 tires stayed on the asphalt. It's like once you reach the limit your grip falls off a cliff hence the suddeness. Street tires are constantly howling at the track, but as you push harder, they scream louder and your senses ie your hearing tells you that you're reaching the limits amongst other things. Your car will also be less responsive at this point but still controllable until you push a little harder and then start to slide at which point its up to you to control what's happening.


Apologies in advance for my need for evidence.

This would suggest that the difference between the static friction and kinetic friction of R-comps is greater than the difference for street tires. While this is likely do you have any real evidence other than subjective ?


Now once you're in a slide it's up to you to bring it back but since 1.) you are going slower with streets you can recover quicker, but also the nature of the rubber will start to regain composure more quickly


nature of the rubber ???? Can you point me to any links which explain this ?



R compounds are faster, and more durable at the track so yes I do recommend everyone to aspire to them, just don't start with them. One more thing I'd like to add, R compounds are very susceptible to tire temperatures. For example your 1st lap out on cold r compounds the will have LESS grip than any street tire.


This is fairly obvious.



As they warm up the tire pressures alter drastically with air and moderately with nitrogen.
Don't listen to anyone that tells you Nitrogen doesn't change tire pressures with temperature...IT DOES! Just not nearly as much as with air.



Well nitrogen is a gas, and actually 78% of air by volume. As a gas nitrogen has to obey the Ideal gas law PV=nR http://en.wikipedia.org/wiki/Ideal_gas_law

If you remove moisture out of the equation (which nitrogen attempts to do ) there should be 0 difference between nitrogen and air.

Keep the answers coming!!!

SiR
04-03-2012, 11:00 AM
I doubt he will sell you it to you for $250.

http://www.memes.at/pics/cereal-guy-spitting-low.jpg

SamE30e
04-03-2012, 12:25 PM
You won't do a S54 swap for $4500.

Make your car better. You don't drive on a track every weekend, and it's not a race car.

njansenv
04-03-2012, 01:22 PM
There's enough variation in "street tires" and "R-compounds" that you shouldn't make generalizations between the two.
A V710 has plenty of stick when at ambient temp on a warm day, for example.
RA1's behave like very sticky, responsive "street tires" in my experience.

I'd recommend learning on RA1's, for example, rather than crappy all seasons...but a good/great street tire like a Direzza Star Spec or RS2, RS3, NT01, or... would be very good for learning. Just my .02.

Dinanstu
04-03-2012, 02:17 PM
dcramer,

The ideal gas law is PV=nrT. Don't forget the 'T'!

All tires have different compounds and different optimal temperature ranges. The handling characteristics of all tires vary, but you know that....everybody knows that.

What exactly do you want to know?

dcramer
04-03-2012, 02:56 PM
Cut and paste, forgot the T

So is the difference between static and kinetic friction dramatically different for R-comp tires vs very good street tires ? Or stated another way do R-comps really break away faster than street tires ?

T.Dot_E30
04-03-2012, 03:24 PM
Or stated another way do R-comps really break away faster than street tires ?

I think you are getting what the others are saying about r-comps wrong. They don't 'break away' faster, it's that you are going much faster when they break loose, therefore making it harder for an unskilled driver to recover if they don't know what they are doing. Also they mask alot of driver mistakes since the limits are higher, so typically screwing up on r-comps has bigger consequences.

Also this is only one school of thought, which differs, everyone is different and learn differently, but this is a more cautious/safer approach to build up speed gradually.

It would probably be akin to jumping into an F1 car without and track or racing experience, you probably want to start off with something easier to learn on...

dcramer
04-03-2012, 03:52 PM
I think you are getting what the others are saying about r-comps wrong. They don't 'break away' faster, it's that you are going much faster when they break loose, therefore making it harder for an unskilled driver to recover if they don't know what they are doing. Also they mask alot of driver mistakes since the limits are higher, so typically screwing up on r-comps has bigger consequences.


Actually this is what I argued in the first place is that they break away the same, but at a faster speed. There is actually some evidence to the contrary, but I'd like to find more.


Also this is only one school of thought, which differs, everyone is different and learn differently, but this is a more cautious/safer approach to build up speed gradually.


FWIW, my formative years of driving were spent driving mostly sideways, first in a field when I was 14, then on country roads. Recovering from slides is not a new concept.

Dinanstu
04-03-2012, 04:02 PM
Static and Kinetic friction is variable with all materials... Silk and sandpaper?

Instructors are giving you good solid advice at a starting point. You have a nice car, and you should be prepared to protect it and yourself and me if I'm on the track too.

There is always a point that the tire (any tire) will have grip to no grip and lose control. The R tires have much more grip, to a point, which will be a higher cornering speed, so when it goes, you go with it. Its very much akin to surface conditions and tire quality..ie snow, rain etc...hence the invention of anti-lock brakes that maximize the tire grip in adverse conditions. Poor tires squeal at the Timmy's drive-through, so you know what the limits are.
The problem here is Mosport can be very unforgiving and you woudn't want your car backed into the wall at turn 1!

Aero
04-03-2012, 05:07 PM
Cut and paste, forgot the T

So is the difference between static and kinetic friction dramatically different for R-comp tires vs very good street tires ? Or stated another way do R-comps really break away faster than street tires ?

The way pneumatic tires generate grip is much more complicated than the Coulomb or "dry" friction model, which involves static and kinetic friction coefficients. Almost any decent modern vehicle dynamics book will have a chapter or more devoted to the subject. Look at offerings from Carroll Smith and Milliken for race car focused discussion. Milliken is the much more technical of the two.

Basically, the issue of "driveability" involves much more than rubber compound alone. Everything from the tire width, sidewall profile, carcass construction, wheel diameter, wheel width, and of course tire compound will affect driveability.

For learning to control a car at its limits, I would think a tire with a low cornering stiffness (makes grip at high slip angles) and one that makes near peak grip over a broad range of slip angles would be best. This points towards a relatively narrow tire with soft carcass/sidewall construction, on a relatively narrow wheel. I don't think this necessarily excludes r-compound rubber, rather that tires using r-compounds typically do not fit the rest of the description.

Alternatively, the approach taken in Karting (very high cornering stiffness and very narrow 'optimal' slip angle range) to learn how to control a car seems to have worked well for most F1 drivers. *th-up*

Food for thought.

And back on topic: my advice would be to get a set of star specs, RS3's, XS's, or similar and spend the rest of your money on registration fees and consumables for track days.

Dinanstu
04-03-2012, 06:56 PM
Ya, thats what I meant....
:)

dcramer
04-04-2012, 08:15 AM
The way pneumatic tires generate grip is much more complicated than the Coulomb or "dry" friction model, which involves static and kinetic friction coefficients. Almost any decent modern vehicle dynamics book will have a chapter or more devoted to the subject. Look at offerings from Carroll Smith and Milliken for race car focused discussion. Milliken is the much more technical of the two.



So which book did you prefer. Milliken's book is considerably more expensive.

Would you recommend one over the other ?

Dave

SiR
04-04-2012, 12:03 PM
milliken book is excellent.

Doesnt hurt to have both if you are into that sort of thing.

Aero
04-04-2012, 03:46 PM
It's tough to recommend one over the other. The authors have very different style.

Smith is much less technical/mathematical and tends to speak from his wealth of experience. Tune to Win is a great book for someone who may not be an engineer, but still wants to learn a bit about vehicle dynamics and car setup.

Race Car Vehicle Dynamics by Milliken is the bible of, well, race car vehicle dynamics. It's much more technical, and is presented with an engineering audience in mind. That said, it is much more thorough and comprehensive. I like it since it presents the fundamental dynamics of the various vehicle systems and builds the analysis from there to arrive at meaningfull conclusions.

So, it really depends what you want to get out of the read. Yup, a typical "It depends" answer from an engineer. :rolleyes:

E30S54
04-25-2012, 09:25 PM
n54 :)