Fine Tuning Rear Brake Bias
06-02-2009, 02:36 AM
#16
Rennlist Member
The race 928s are about 56 /44% weight distribution with us in the car near 3000lbs. Brian will have to watch the lack of rebound in the rear with his trail braking and even just fast transistion turns.. ever see street cars do the slalom courses? they get so much roll that the amount of mass moving side to side is traveling a greater distance and is higher and is creating more force against the turn. initial bite migh be good (low rebound rear) and even that one turn might be good, its straigtening it out and/or changing the direction that would be the problem. (besides effecting trail braking)
mk
mk
Brian, I bet the widow is much lighter than my Street GTS and that would make a difference in the bias timing. The rear springs really don't effect braking. If you don't have adjustable rebound on the rear, for a quick fix you could go to a lesser pad on the back to reduce the rear braking.
06-02-2009, 02:44 AM
#17
Rennlist Member
well, if you are consistant, that could be the problem. the car will have more motion longitudinally, so that will require a different launch. anyway, going softer in the rear may or may not help with rear grip acceleration. as was said, you want the lowest Cg height. for a given G acceleration, the weight transfer is independent of suspension, anti squat, etc. its all, Cg height, wheel base, and overall weight.
mk
mk
Go try the front rebound setting acceleration thing. And it's not a hole shot, get the car rolling then floor it. Unless your car is so underpowered it can't spin the tires at full firm, or so overpowered it can't not spin the tires at full soft you will be surprised.
I am absolutely certain it is NOT a difference in my throttle application. If anything I am very very consistent. I did some intercooler testing on a turbo at a test and tune night at the local drag strip. I did two runs with each of 3 different intercoolers. The goal was to be as consistent as possible to check the differences in the intercoolers. My two runs with each intercooler were within .003 seconds of each other. That is so consistent the local bracket or dial-in racers said I should be doing dial-in. The announcer at the dragstrip was even talking me up and telling the crowd what I was doing. The bracket winners usually have .020 to .030 seconds between their runs and that's what they are shooting for.
I am absolutely certain it is NOT a difference in my throttle application. If anything I am very very consistent. I did some intercooler testing on a turbo at a test and tune night at the local drag strip. I did two runs with each of 3 different intercoolers. The goal was to be as consistent as possible to check the differences in the intercoolers. My two runs with each intercooler were within .003 seconds of each other. That is so consistent the local bracket or dial-in racers said I should be doing dial-in. The announcer at the dragstrip was even talking me up and telling the crowd what I was doing. The bracket winners usually have .020 to .030 seconds between their runs and that's what they are shooting for.
06-02-2009, 07:08 AM
#18
Rennlist Member
This thread has drifted a bit from the original topic which
was brake bias rather than handling. Mark stated that after
racing his rear brakes were much cooler than the fronts.
Does this mean he is running a fixed front/ rear bias.
If this is the case he is not geting full value from his rear brakes
and it is usually under braking that you get advantages on the track.
My old Triumph Dolomite Sprint had a variable rate brake bias/
anti lock device to prevent rear wheel lock up. It consisted of
a variable valve fixed to the body actuated by a push/ pull rod
fixed to the rear axle. As the weight of the car went forward
under hard braking the rear of the car rose and the pressure in
the rear brake line was reduced . This was fine to stop grannies
getting into trouble panic braking on a wet road but it cut in far to
soon when pressing on. Also since it depended on movement in
the rear suspension
For track use I removed the variable valve, rerouted the rear
brake pipe through the cockpit and put in a directly controlled pressure
limiting valve (Tilton rotary) that could be adjusted from the drivers seat when driving.
I could find the point where the rears just started to lock up before the
fronts then back it of a liittle. This system could be adjusted even on track
to suit changes in track condition such as rain or temperature.
I am surprised that a system like this or even two master cylinders
with an adjustable balance bar in not the norm on 928 race/ track cars.
928s with the gearbox over the rear wheels should be able to get some sort
of braking advantage over other front engined cars that have more weight over
their front wheels. If Marks rear brakes are not getting very hot then he
is losing some of the available braking force. It may not be a lot since
under heavy braking the rears are lightly loaded but in racing every small
detail counts. We have read about Marks work on improving the front
brakes on his racer but maybe he is leaving speed "on the table" by not
looking to the rears.
was brake bias rather than handling. Mark stated that after
racing his rear brakes were much cooler than the fronts.
Does this mean he is running a fixed front/ rear bias.
If this is the case he is not geting full value from his rear brakes
and it is usually under braking that you get advantages on the track.
My old Triumph Dolomite Sprint had a variable rate brake bias/
anti lock device to prevent rear wheel lock up. It consisted of
a variable valve fixed to the body actuated by a push/ pull rod
fixed to the rear axle. As the weight of the car went forward
under hard braking the rear of the car rose and the pressure in
the rear brake line was reduced . This was fine to stop grannies
getting into trouble panic braking on a wet road but it cut in far to
soon when pressing on. Also since it depended on movement in
the rear suspension
For track use I removed the variable valve, rerouted the rear
brake pipe through the cockpit and put in a directly controlled pressure
limiting valve (Tilton rotary) that could be adjusted from the drivers seat when driving.
I could find the point where the rears just started to lock up before the
fronts then back it of a liittle. This system could be adjusted even on track
to suit changes in track condition such as rain or temperature.
I am surprised that a system like this or even two master cylinders
with an adjustable balance bar in not the norm on 928 race/ track cars.
928s with the gearbox over the rear wheels should be able to get some sort
of braking advantage over other front engined cars that have more weight over
their front wheels. If Marks rear brakes are not getting very hot then he
is losing some of the available braking force. It may not be a lot since
under heavy braking the rears are lightly loaded but in racing every small
detail counts. We have read about Marks work on improving the front
brakes on his racer but maybe he is leaving speed "on the table" by not
looking to the rears.
06-02-2009, 09:02 AM
#19
Rennlist Member
Thread Starter
To put this in terms of grip under braking, softer rear rebound gives the fronts better initial braking. So the goal of adjusting the rear bias valve and rear rebound is to take advantage of any rear braking not being used in the transition from accelerating to full weight transferred fronts doing all the work threshold braking.
I like mine setup so that when I slowly lift off the brakes as I apply steering for turn-in the rear starts rotating and getting back on the throttle stops the rotation putting the car in a slight 4 wheel drift heading for the apex. The higher bias valve provides more rear braking at higher pedal pressure increasing the turn-in trail braking rotation point.
Last edited by RKD in OKC; 06-02-2009 at 10:03 AM.
06-02-2009, 11:43 AM
#20
Rennlist Member
In the first post RKD refers to the ABS point.
I take this to mean that her competes with the ABS active.
The 928 ABS system is OK for keeping you out of
trouble on the roads but it is a fairly old design and
is a bit "clunky" for want of a better word. I feel it with
a modern system.
I have not tracked my 928 yet but with previous cars I
would pull the ABS circuit fuse for track days and control
the braking myself. On a track I certainly found I could
brake harder without the ABS getting in the way.
Another brake mod. I have not seen mentioned is to fit
pressure retention valves in the front brake lines.
On other cars I have tracked wider tyres, improved suspension
and higher cornering speeds have caused the front uprights and
stub axles to flex and with the rotors not running true the pads
get knocked back causing long pedal stroke which can be alarming.
The valves keep a low brake fluid pressure in the callipers when
your foot is off the pedal preventing knock back and giving a much
more solid feel to the brakes. Would this be a useful mod to the 928
or do they not suffer from this problem?
So do you guys that race or X-cross use the ABS or not?
I take this to mean that her competes with the ABS active.
The 928 ABS system is OK for keeping you out of
trouble on the roads but it is a fairly old design and
is a bit "clunky" for want of a better word. I feel it with
a modern system.
I have not tracked my 928 yet but with previous cars I
would pull the ABS circuit fuse for track days and control
the braking myself. On a track I certainly found I could
brake harder without the ABS getting in the way.
Another brake mod. I have not seen mentioned is to fit
pressure retention valves in the front brake lines.
On other cars I have tracked wider tyres, improved suspension
and higher cornering speeds have caused the front uprights and
stub axles to flex and with the rotors not running true the pads
get knocked back causing long pedal stroke which can be alarming.
The valves keep a low brake fluid pressure in the callipers when
your foot is off the pedal preventing knock back and giving a much
more solid feel to the brakes. Would this be a useful mod to the 928
or do they not suffer from this problem?
So do you guys that race or X-cross use the ABS or not?
06-02-2009, 01:33 PM
#21
Rennlist Member
If under braking, you have a weight transfer of near 800lbs, this means that my 3000lb car with 1700 up front and 1300 in the rear just went to 2500lbs up front and 500lbs in the rear. (not using exact numbers) . Isnt it very easy to say that the braknig force on the rear of the car with 500lbs should have less braking force (or contribution) compared to the 2500lbs sitting on the front wheels?? As I mentioned, and I have done quite a bit of experimenting on threashold braking on the 928, with the new brakes up front, and the bigger and stickier tires up front, I'm using even MORE force up front and having even MORE weight transfer AND using MORE rear brakes than before, and now seeing some rotation due to increased rear brake effectiveness.
Does this make sense or am I missing the point?
mk
Does this make sense or am I missing the point?
mk
This thread has drifted a bit from the original topic which
was brake bias rather than handling. Mark stated that after
racing his rear brakes were much cooler than the fronts.
Does this mean he is running a fixed front/ rear bias.
If this is the case he is not geting full value from his rear brakes
and it is usually under braking that you get advantages on the track.
My old Triumph Dolomite Sprint had a variable rate brake bias/
anti lock device to prevent rear wheel lock up. It consisted of
a variable valve fixed to the body actuated by a push/ pull rod
fixed to the rear axle. As the weight of the car went forward
under hard braking the rear of the car rose and the pressure in
the rear brake line was reduced . This was fine to stop grannies
getting into trouble panic braking on a wet road but it cut in far to
soon when pressing on. Also since it depended on movement in
the rear suspension
For track use I removed the variable valve, rerouted the rear
brake pipe through the cockpit and put in a directly controlled pressure
limiting valve (Tilton rotary) that could be adjusted from the drivers seat when driving.
I could find the point where the rears just started to lock up before the
fronts then back it of a liittle. This system could be adjusted even on track
to suit changes in track condition such as rain or temperature.
I am surprised that a system like this or even two master cylinders
with an adjustable balance bar in not the norm on 928 race/ track cars.
928s with the gearbox over the rear wheels should be able to get some sort
of braking advantage over other front engined cars that have more weight over
their front wheels. If Marks rear brakes are not getting very hot then he
is losing some of the available braking force. It may not be a lot since
under heavy braking the rears are lightly loaded but in racing every small
detail counts. We have read about Marks work on improving the front
brakes on his racer but maybe he is leaving speed "on the table" by not
looking to the rears.
was brake bias rather than handling. Mark stated that after
racing his rear brakes were much cooler than the fronts.
Does this mean he is running a fixed front/ rear bias.
If this is the case he is not geting full value from his rear brakes
and it is usually under braking that you get advantages on the track.
My old Triumph Dolomite Sprint had a variable rate brake bias/
anti lock device to prevent rear wheel lock up. It consisted of
a variable valve fixed to the body actuated by a push/ pull rod
fixed to the rear axle. As the weight of the car went forward
under hard braking the rear of the car rose and the pressure in
the rear brake line was reduced . This was fine to stop grannies
getting into trouble panic braking on a wet road but it cut in far to
soon when pressing on. Also since it depended on movement in
the rear suspension
For track use I removed the variable valve, rerouted the rear
brake pipe through the cockpit and put in a directly controlled pressure
limiting valve (Tilton rotary) that could be adjusted from the drivers seat when driving.
I could find the point where the rears just started to lock up before the
fronts then back it of a liittle. This system could be adjusted even on track
to suit changes in track condition such as rain or temperature.
I am surprised that a system like this or even two master cylinders
with an adjustable balance bar in not the norm on 928 race/ track cars.
928s with the gearbox over the rear wheels should be able to get some sort
of braking advantage over other front engined cars that have more weight over
their front wheels. If Marks rear brakes are not getting very hot then he
is losing some of the available braking force. It may not be a lot since
under heavy braking the rears are lightly loaded but in racing every small
detail counts. We have read about Marks work on improving the front
brakes on his racer but maybe he is leaving speed "on the table" by not
looking to the rears.
Last edited by mark kibort; 06-02-2009 at 02:52 PM.
06-02-2009, 01:45 PM
#22
Rennlist Member
You are missing the point. I agree to a point. But you are not describing what is really going on. I was trying to show that it is not weight transfer, but the wheels doing something not connected to the body for the first instant. (if you can think of it that way). It has an effect, but it is a tuneable effect that has a sweet spot. Don't confuse the initial bite with the constant acceleration for brief moment out of the hole. The front end raising, raises the Cg which is bad for grip overall. Same thing laterally, the lower the car, the less weight transfer needed to run the same G loading. Under braking, same thing. You have to ease on the brakes to match the grip available, which will follow weight transfer. Too much roll forward will hurt grip (g capabilities and thus reduce weight transfer or keep it the same with a higher Cg height, which will lower G deceleration.
you are going on feelings where some are pointing you in the right direction but could hurt performance if you pass the point of effectiveness. On a road course, you dont want the car to move much laterally, or longitudinally for obvious reasons.
Again, rear brakes on a race car are a fine tuning element. 2500lbs on my car under full threashold braking vs 500lbs on the rear end of the car. Im getting only 100degrees F temp difference rotor to rotor and a slight slide under trail braking into slow corners from fast straights. The nice thing about the 928 is it can handle the rear end slide REALLY well to rotate the car around turns very controllably and fast.
check out some video of how the brake set up works on the stock S4 with stock engine and stock brakes vs the competition coupe 8.3 liter 520hp viper!
http://www.youtube.com/swf/l.swf?swf...in-car%20%20ea...
mk
you are going on feelings where some are pointing you in the right direction but could hurt performance if you pass the point of effectiveness. On a road course, you dont want the car to move much laterally, or longitudinally for obvious reasons.
Again, rear brakes on a race car are a fine tuning element. 2500lbs on my car under full threashold braking vs 500lbs on the rear end of the car. Im getting only 100degrees F temp difference rotor to rotor and a slight slide under trail braking into slow corners from fast straights. The nice thing about the 928 is it can handle the rear end slide REALLY well to rotate the car around turns very controllably and fast.
check out some video of how the brake set up works on the stock S4 with stock engine and stock brakes vs the competition coupe 8.3 liter 520hp viper!
http://www.youtube.com/swf/l.swf?swf...in-car%20%20ea...
mk
LOL. So there IS A DIFFERENCE or it wouldn't require a different launch. And during that more motion (the transition from one speed to another) with the softer front rebound the rear tires get a better initial bite. AND that front stays lifted as long as you are accelerating effectively raising the ride height of the front end quite a bit.
To put this in terms of grip under braking, softer rear rebound gives the fronts better initial braking. So the goal of adjusting the rear bias valve and rear rebound is to take advantage of any rear braking not being used in the transition from accelerating to full weight transferred fronts doing all the work threshold braking.
I like mine setup so that when I slowly lift off the brakes as I apply steering for turn-in the rear starts rotating and getting back on the throttle stops the rotation putting the car in a slight 4 wheel drift heading for the apex. The higher bias valve provides more rear braking at higher pedal pressure increasing the turn-in trail braking rotation point.
To put this in terms of grip under braking, softer rear rebound gives the fronts better initial braking. So the goal of adjusting the rear bias valve and rear rebound is to take advantage of any rear braking not being used in the transition from accelerating to full weight transferred fronts doing all the work threshold braking.
I like mine setup so that when I slowly lift off the brakes as I apply steering for turn-in the rear starts rotating and getting back on the throttle stops the rotation putting the car in a slight 4 wheel drift heading for the apex. The higher bias valve provides more rear braking at higher pedal pressure increasing the turn-in trail braking rotation point.
Last edited by mark kibort; 06-02-2009 at 02:55 PM.
06-02-2009, 01:55 PM
#23
Rennlist Member
no pedal issues at all with the stock 928 S4 brake system.
Ive used ABS as much as I havent used it. (I dont use it, but its there as a safety net) It is only good as an early warning system for threashold braking. I can feel wheel slip, but the ABS makes it a little more known that you are over the limit and to back off. all it ends up doing is keeping you from flat spotting a tire should you get into a panic stop situation, oil or gravel lock up prevention. you cant use it, as the stopping distances seem to be about double if I was to guess.
The only time i got a long pedal was when my rotors were badly cracked and warped pushing the pads in during the long straights. not bad, but enough to notice. these rotors were REALLY bad. with good parts, no issues.
mk
Ive used ABS as much as I havent used it. (I dont use it, but its there as a safety net) It is only good as an early warning system for threashold braking. I can feel wheel slip, but the ABS makes it a little more known that you are over the limit and to back off. all it ends up doing is keeping you from flat spotting a tire should you get into a panic stop situation, oil or gravel lock up prevention. you cant use it, as the stopping distances seem to be about double if I was to guess.
The only time i got a long pedal was when my rotors were badly cracked and warped pushing the pads in during the long straights. not bad, but enough to notice. these rotors were REALLY bad. with good parts, no issues.
mk
In the first post RKD refers to the ABS point.
I take this to mean that her competes with the ABS active.
The 928 ABS system is OK for keeping you out of
trouble on the roads but it is a fairly old design and
is a bit "clunky" for want of a better word. I feel it with
a modern system.
I have not tracked my 928 yet but with previous cars I
would pull the ABS circuit fuse for track days and control
the braking myself. On a track I certainly found I could
brake harder without the ABS getting in the way.
Another brake mod. I have not seen mentioned is to fit
pressure retention valves in the front brake lines.
On other cars I have tracked wider tyres, improved suspension
and higher cornering speeds have caused the front uprights and
stub axles to flex and with the rotors not running true the pads
get knocked back causing long pedal stroke which can be alarming.
The valves keep a low brake fluid pressure in the callipers when
your foot is off the pedal preventing knock back and giving a much
more solid feel to the brakes. Would this be a useful mod to the 928
or do they not suffer from this problem?
So do you guys that race or X-cross use the ABS or not?
I take this to mean that her competes with the ABS active.
The 928 ABS system is OK for keeping you out of
trouble on the roads but it is a fairly old design and
is a bit "clunky" for want of a better word. I feel it with
a modern system.
I have not tracked my 928 yet but with previous cars I
would pull the ABS circuit fuse for track days and control
the braking myself. On a track I certainly found I could
brake harder without the ABS getting in the way.
Another brake mod. I have not seen mentioned is to fit
pressure retention valves in the front brake lines.
On other cars I have tracked wider tyres, improved suspension
and higher cornering speeds have caused the front uprights and
stub axles to flex and with the rotors not running true the pads
get knocked back causing long pedal stroke which can be alarming.
The valves keep a low brake fluid pressure in the callipers when
your foot is off the pedal preventing knock back and giving a much
more solid feel to the brakes. Would this be a useful mod to the 928
or do they not suffer from this problem?
So do you guys that race or X-cross use the ABS or not?
06-02-2009, 03:27 PM
#24
Rennlist Member
Thread Starter
Okay, I'll take this one on. With bigger sticker tires you are using less brake pressure to get the same job done so the rears are seeing more initial brake time. There is also a difference in fluid volume for bigger front brakes that would also contribute to more rear initial braking that would create the higher temperatures you are seeing on the rear brakes. As for more rear rotation, if you went stickier without changing rebound, you are getting rear lift that is contributing to more rotation on turn-in.
06-02-2009, 03:35 PM
#25
Rennlist Member
as a note, I would do full throttle acceleration in the driveway with the rears up in the air. know how I would keep the 320rwhp from running through redline?
Right.... I applied the brakes. I would ride the brakes and floor it. i could barely stablize the rpm under full throttle. ABS would go crazy though. But, the point is, stock bias does provide some rear braking. I dont go through rear pads on the track (as I said, 10:1) but with weight transfer of near 800lbs front to rear, thats a 3:1 change in weight balance. Plus, you woldnt want the braking force to be exactly proportional either as the tail would be all over the place in trail braking and into fast transition turns. So, the 10:1 rear to front pad wear is probalby light, along with the temp measurements of 100F degrees difference from front to rear in the paddock after a race session.
sure, I think I could use the 33 bar vs the 11 bar currently used. But, its fine tuning.
mk
Right.... I applied the brakes. I would ride the brakes and floor it. i could barely stablize the rpm under full throttle. ABS would go crazy though. But, the point is, stock bias does provide some rear braking. I dont go through rear pads on the track (as I said, 10:1) but with weight transfer of near 800lbs front to rear, thats a 3:1 change in weight balance. Plus, you woldnt want the braking force to be exactly proportional either as the tail would be all over the place in trail braking and into fast transition turns. So, the 10:1 rear to front pad wear is probalby light, along with the temp measurements of 100F degrees difference from front to rear in the paddock after a race session.
sure, I think I could use the 33 bar vs the 11 bar currently used. But, its fine tuning.
mk
The stock bias does not provide nearly enough rear braking, period. The rear brakes essentially do nothing with it. I was working on an automatic car the other day and with the rear wheels in the air and in drive, it was all the rear circuit could do to stop the wheel from spinning at idle. I have the 33 in my 84. I wish I would have put the 55 in. Be forewarned though, with a higher pressure regulator the backend will get more tailhappy under braking (trail braking becomes much more effective).
06-02-2009, 03:43 PM
#26
Rennlist Member
Thats where driving style comes in. There is low speed and high speed rebound. which are you talking about? driving style can effectivly negate the high speed rebound difference, and during a long, forceful stop, all shocks will raise the rear end, based on front spring rates, not rear rebound. I am using more front brake pressure as I have much more front grip. my initial bite is the same but I am applying much more pressure during the mid point of a long and hard braking period. (rebound and compression settings are not really a factor as the springs now are the main factor for body roll forward or laterially).
Rebound and compression settings, especially the high speed part, are for initial turn in or anti squat, anti dive. There are a 1000 factors here.
It will make your head spin if you think about it too much. The bottomline, its fine tuning. driving a street car on the track without DOT tires, you are pissing in the wind. Im sure i can drive your car right now on the track and find 10 things , or do 10 things that will make it much quicker. Lock that rear rebound down full stiff and I'm sure It will be faster around the track, but you might have to drive it differently!
mk
Rebound and compression settings, especially the high speed part, are for initial turn in or anti squat, anti dive. There are a 1000 factors here.
It will make your head spin if you think about it too much. The bottomline, its fine tuning. driving a street car on the track without DOT tires, you are pissing in the wind. Im sure i can drive your car right now on the track and find 10 things , or do 10 things that will make it much quicker. Lock that rear rebound down full stiff and I'm sure It will be faster around the track, but you might have to drive it differently!
mk
Okay, I'll take this one on. With bigger sticker tires you are using less brake pressure to get the same job done so the rears are seeing more initial brake time. There is also a difference in fluid volume for bigger front brakes that would also contribute to more rear initial braking that would create the higher temperatures you are seeing on the rear brakes. As for more rear rotation, if you went stickier without changing rebound, you are getting rear lift that is contributing to more rotation on turn-in.
06-02-2009, 07:09 PM
#27
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tran⋅sient
/ˈtrænʃənt, -ʒənt, -ziənt/ Show Spelled [tran-shuhnt, -zhuhnt, -zee-uhnt] Show IPA
–adjective
1.not lasting, enduring, or permanent; transitory.
2.lasting only a short time; existing briefly; temporary: transient authority.
3.staying only a short time: the transient guests at a hotel.
4.Philosophy. transeunt.
–noun
5.a person or thing that is transient, esp. a temporary guest, boarder, laborer, or the like.
6.Mathematics.
a.a function that tends to zero as the independent variable tends to infinity.
b.a solution, esp. of a differential equation, having this property.
7.Physics.
a.a nonperiodic signal of short duration.
b.a decaying signal, wave, or oscillation.
8.Electricity. a sudden pulse of voltage or current.
/ˈtrænʃənt, -ʒənt, -ziənt/ Show Spelled [tran-shuhnt, -zhuhnt, -zee-uhnt] Show IPA
–adjective
1.not lasting, enduring, or permanent; transitory.
2.lasting only a short time; existing briefly; temporary: transient authority.
3.staying only a short time: the transient guests at a hotel.
4.Philosophy. transeunt.
–noun
5.a person or thing that is transient, esp. a temporary guest, boarder, laborer, or the like.
6.Mathematics.
a.a function that tends to zero as the independent variable tends to infinity.
b.a solution, esp. of a differential equation, having this property.
7.Physics.
a.a nonperiodic signal of short duration.
b.a decaying signal, wave, or oscillation.
8.Electricity. a sudden pulse of voltage or current.
06-02-2009, 11:16 PM
#28
Rennlist Member
Thread Starter
I am not new to car setup. I learned setup with a 944 Turbo S. Doing nothing to the stock car except springs, adjustable sway bars, and adjusting the rebound on the stock Koni Yellows I could easily match the fastest cars and drivers the few times I went to Hallett. At my local time trial and autocross events I was the one to beat. I did not gut the car or have the suspension so stiff it would rattle your teeth on the street to make it fast either. It was my daily driver. And I did have help setting up and tuning from Andial and several other "old school" racers. The goal was the best of compromises to be an all round do anything car.
That is also the goal on my GTS so I am sure that since it is a fully loaded street car with all the cumfy fluff there are many improvements that could be made if it were a dedicated track car. Heck, I am running stock ride heights to help protect the hangy downy bits from road hazzards and my alignment is the aggressive limit of stock spec. But that doesn't keep me from using the adjustability of the sway bars, Koni Red shock rebound (there is only one adjustment), and brake bias valve to make it handle it's best when driven at the limits.
That is also the goal on my GTS so I am sure that since it is a fully loaded street car with all the cumfy fluff there are many improvements that could be made if it were a dedicated track car. Heck, I am running stock ride heights to help protect the hangy downy bits from road hazzards and my alignment is the aggressive limit of stock spec. But that doesn't keep me from using the adjustability of the sway bars, Koni Red shock rebound (there is only one adjustment), and brake bias valve to make it handle it's best when driven at the limits.
Last edited by RKD in OKC; 06-03-2009 at 01:25 AM.
06-03-2009, 01:10 AM
#29
Rennlist Member
No disrespect intended. Hey, like you I was always the softest car set up out there, among a sea of guys all with over sprung cars. I think we are both talking about the same types of things, but I was just trying to be clear about weight transfer. Certainly, we all know changes in rebound, compression, spring rate and a dozen other factors help a car get out of the hole, on the brakes and in and out of turns. The reasons are far less intuitive.
Now, your grandious claim of the fastest driver on any circuit in a stock 944 tubo? It wouldnt do to well against us in ITE FYI.
mk
Now, your grandious claim of the fastest driver on any circuit in a stock 944 tubo? It wouldnt do to well against us in ITE FYI.
mk
I am not new to car setup. I learned setup with a 944 Turbo. Doing nothing to the stock car except springs and swaybars I could easily match the fastest cars and drivers on any circuit. At my local events I was the one to beat. I did not gut the car or have the suspension so stiff it would rattle your teeth on the street to make a track car out of it either. And I did have help setting up and tuning from Andial and several other "old school" racers.
But I am sure that since my car is still basically a street car there are improvements to be made. Nothing is perfect.
But I am sure that since my car is still basically a street car there are improvements to be made. Nothing is perfect.
06-03-2009, 01:34 AM
#30
Rennlist Member
Thread Starter
Okay, I edited my claim. The circuit was Hallett and the drivers were Ron Forstall in his club race prepped 996 twin turbo, and also Kim Krumb in his 928 at the first 928 Owner's Club convention. Both sought me out to see what my 944 had in it to be able to keep up with them.