Flux

Today was one of the best days at the track I have ever had - the car felt so solid and responsive and I got into that rhythm where the laps just clip by and you're knocking them off 12 in a row within a tenth of each other. Plus my fastest lap was a full 1.8 seconds faster than my previous best.

Had some fun with some Porsche guys, a bunch of modified Miatas and a big, burly Mustang GT. I really like being on the track with other cars - just not when they hold me up. I seem to concentrate better and drive more smoothly for some reason when I am running down a 200hp turbo Miata.

Fist time at the track with the Mugen baffled pan, new Cobalt GT-Sport rear pads and Motul Gear 300 transmission fluid. No comment on the pan's performance... I really like the Motul transmission fluid - shifts felt nice and clean and smooth and never had a problem coming down into second like would happen with the Honda MTF. The Cobalt rear pads are great when running the Spec VR up front. I will be using Cobalt pads till the day I die...

My heel-toe downshifting sucks (see other thread) and it really is slowing me down and limiting my progress. More practice needed...

I ran a stiffer rear/softer front damper setting for some of the sessions today and I liked it. Car certainly rotated differently and twitched a bit under braking - but I had some fast times with this set-up and will continue to use it in the future.

Kendall

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">I ran a stiffer rear/softer front damper setting for some of the sessions today and I liked it. Car certainly rotated differently and twitched a bit under braking - but I had some fast times with this set-up and will continue to use it in the future. </TD></TR></TABLE>

Are you using a stock rear sway bar, and what spring rates are you using?

Chris F

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">I ran a stiffer rear/softer front damper setting for some of the sessions today and I liked it. Car certainly rotated differently and twitched a bit under braking - but I had some fast times with this set-up and will continue to use it in the future. </TD></TR></TABLE>

On my Konis, I used to run 3/4 stiff rear (always, never bothered changing it), full stiff front for autocross, and I played a lot with it in the front (started stiff and worked backwards). I liked it soft, too.

(SSNHTS traitor! )

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Kendall &raquo;</TD></TR><TR><TD CLASS="quote">Are you using a stock rear sway bar, and what spring rates are you using?</TD></TR></TABLE>

I have the 23mm JDM rear sway bar. Spring rates are 12k/10k,

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">(SSNHTS traitor! )</TD></TR></TABLE>

Don't worry - I practiced that too...

Kendall

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">(SSNHTS traitor! )</TD></TR></TABLE>

Hey, just because you think driving like a grandma is cool, doesn't mean it works for everyone.

Flux

I also learned today what a 260lb passenger does to braking, transitions and acceleration... (about 2-2.5 seconds/lap)

RTW DC2R

sounds good. I remember you had a post about trying to tune your settings and whatnot. Have you had a chance to make changes and notice a difference on the track? what steps have you taken so far in regards to different settings/changes you have made?

what tires are you running?

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW &raquo;</TD></TR><TR><TD CLASS="quote">sounds good. I remember you had a post about trying to tune your settings and whatnot. Have you had a chance to make changes and notice a difference on the track? what steps have you taken so far in regards to different settings/changes you have made?

what tires are you running?</TD></TR></TABLE>

Yes - I am tracking all my changes and all my posts include what I have done mostly. So far medium/softer damper settings (about 7 or 8 out of 15) are quicker around this particular track with it bumpy braking zones. I really started losing time when I was up in 13-15 out of 15 in the front.

I am now starting to play with a stiffer rear damper bias. The car feels a bit more nervous, particularly through 2 of the corners and braking is not quite as stable - but it does seem to be a bit faster, although not enough data yet to really compare.

I am running the Falken Azenis (215) but plan on getting some Toya RA1s soon...

Nishant

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">

Yes - I am tracking all my changes and all my posts include what I have done mostly. So far medium/softer damper settings (about 7 or 8 out of 15) are quicker around this particular track with it bumpy braking zones. I really started losing time when I was up in 13-15 out of 15 in the front.

I am now starting to play with a stiffer rear damper bias. The car feels a bit more nervous, particularly through 2 of the corners and braking is not quite as stable - but it does seem to be a bit faster, although not enough data yet to really compare.

I am running the Falken Azenis (215) but plan on getting some Toya RA1s soon...</TD></TR></TABLE>

i'd get used to the suspension and adjusting before going to R comps. I tried this and it hasn't worked out too well. I am gonna run street tires at my next track even then go back to R comps. I think its easier to tune the suspension on street tires

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Nishant &raquo;</TD></TR><TR><TD CLASS="quote">

i'd get used to the suspension and adjusting before going to R comps. I tried this and it hasn't worked out too well. I am gonna run street tires at my next track even then go back to R comps. I think its easier to tune the suspension on street tires</TD></TR></TABLE>

I'm very comfortable with the suspension and suspension tuning - I have been running and tuning this set-up for years for auto-x and track days. The only difference now is that I have a way to capture lap times so I have some qualitative data that reflects changes to the car's set-up.

Chris93Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">I really like the Motul transmission fluid - shifts felt nice and clean and smooth and never had a problem coming down into second like would happen with the Honda MTF. </TD></TR></TABLE>

I've noticed since switching to the Motul fluid my shifts are really smooth too, I'd give the stuff a definite

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">My heel-toe downshifting sucks (see other thread) and it really is slowing me down and limiting my progress. More practice needed...</TD></TR></TABLE>

Dude seriously we share a brain, this is what I feel is holding me back the most too. Just when I'm really getting into a rhythm on track I totally boner a downshift Hopefully we'll both get betteR

PS - I'm still totally jealous of you living so close to that track

Chris93Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">I am now starting to play with a stiffer rear damper bias. The car feels a bit more nervous, particularly through 2 of the corners and braking is not quite as stable - but it does seem to be a bit faster, although not enough data yet to really compare..</TD></TR></TABLE>

Time for Mugen wing???? I'm hoping for a noticeable improvement in stability under braking w/ it installed :fingers crossed:

RTW DC2R

do you think you are actually going fast enough into and through a turn for the mugen wing to provide more downforce? I could understand if this was F1, but I find it hard to believe on a street car.

Nishant

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Flux &raquo;</TD></TR><TR><TD CLASS="quote">

I'm very comfortable with the suspension and suspension tuning - I have been running and tuning this set-up for years for auto-x and track days. The only difference now is that I have a way to capture lap times so I have some qualitative data that reflects changes to the car's set-up.</TD></TR></TABLE>

ahh if thats the case, r comps should be no problem

Chris93Si

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RTW DC2R &raquo;</TD></TR><TR><TD CLASS="quote">do you think you are actually going fast enough into and through a turn for the mugen wing to provide more downforce? I could understand if this was F1, but I find it hard to believe on a street car. </TD></TR></TABLE>

Into and through a turn I dunno, from what I understand the Mugen wing really helps keep the car stable under heavy braking.

George Knighton

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris93Si &raquo;</TD></TR><TR><TD CLASS="quote">... from what I understand the Mugen wing really helps keep the car stable under heavy braking. </TD></TR></TABLE>

Hmm. That means it introduces drag if that's what it's doing, right?

The bodywork is definitely stable at 150 miles per hour, which is about ten miles per hour more than most of us would see on the typical 2.5 mile course. At extremely high speeds, sure, the wing would introduce some drag on the rear end when the nose dipped down as you went into threshold braking.

I dunno.

I'm doubtful this is the best way to accomplish this.

The reason the rear end gets so light is because your springs are light enough that the nose comes down and radically increases the front tread patch, accentuating the slightest movement on the steering wheel, and exaggerating whatever effect being slightly off centre of straight was going to have.

Additionally, as the rear end raises up off the springs, the wheels go positive camber and toe out, and the tread patch in the rear is lessened.

If you're driving well enough that you are reaching speeds of 140 or so at the end of a long straight, you might want to consider heavier springs on the front to keep the nose up (and this means heavier springs in the rear to preserve the balance).

You might also want to make sure that your rear brake pads are appropriate and that they complement the front brake pad compound.

Another trick you learn as you get faster is that, despite conventional wisdom to the contrary, it helps to have a little toe in on the rear.

Chris F

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by George Knighton &raquo;</TD></TR><TR><TD CLASS="quote">You might also want to make sure that your rear brake pads are appropriate and that they complement the front brake pad compound.</TD></TR></TABLE>

What does appropriate mean?

At x MPH, lock up all 4 at the same time?
At x MPH, lock up the fronts first?
At x MPH, lock um the rears first?

And, what is x MPH?

I can't figure out what makes a car more or less unstable in braking, front or rear bias. Someone says rear bias, and I believe them, because you can do donuts in the car if your rear locks up.

Someone else says too much front bias makes the car a little unstable, because if your rear moves to the side, the braking vector of the front wheels trys to spin your car, whereas the braking vector on the rear tires tries to keep the rear behind the front.

An analogy might be, sorta, if you had a disc sliding down a snowy hill, but there was a rough edge on the disk that was doing more braking. The rough edge would spin the disk to try to pull that edge towards the back of the car.

But at the same time, using more rear brakes reduces the amount of adhesion available for keeping the rear from moving side to side.

But on the other hand, using more rear brakes reduces the weight transfer.

George, your post made me dizzy.

-Chris

George Knighton

You don't need the same compound front and rear; however, most people need a stronger compound in the rear than they realise.

In other words Spec VR on the front and Spec C on the rear makes sense, assuming a good suspension.

Spec VR on the front and OEM does not make sense. Sure you could manage it, but the car won't be doing its best.

(In discussing any of this we have to realise that most of the problems we have are related to the driver's training and state of mind, too.)

You will stop the fastest in any given situation if all four wheels are at impending lockup at about the same time, and the brake pads and brake pressure balance and ABS need to all be working to achieve this.

With most cars locking up the fronts first will be more stable, but it won't slow the car as fast as it could be slowing.

Chris F

Thanks George.

-Chris

MattD@Stoptech

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris F &raquo;</TD></TR><TR><TD CLASS="quote">
But on the other hand, using more rear brakes reduces the weight transfer.
</TD></TR></TABLE>

Weight transfer is only a function of geometry and vehicle acceleration. Now, brake balance will affect it indirectly, whereas the better the brake balance the higher the decelerating force, and the larger the weight transfer.

Most stable car will have no brakes in the rear and will lock up the fronts...it will also take a while to stop, and won't be very steerable. Braking dynamics are always a compromise between steerability, stability, and stopping distances, they are all inversly proportional.

Also, stiffer springs will have no effect on weight trasnfer, but will prevent some(unwanted?) suspension geometry changes.

MattD@Stoptech

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chris93Si &raquo;</TD></TR><TR><TD CLASS="quote">

Into and through a turn I dunno, from what I understand the Mugen wing really helps keep the car stable under heavy braking. </TD></TR></TABLE>

I'd spend money on the the mugen trailing arm bushings, if the money were mine....and I wanted to increase braking stability.

Chris F

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">Weight transfer is only a function of geometry and vehicle acceleration. </TD></TR></TABLE>

I just drew out a couple diagrams to prove you wrong, and ended up proving you totally right. Boy was I surprised. Let me know if you really care to see them.

Must be some other phenomenon that causes the rear to droop when pulling the e-brake on a 1G Integra, likely suspension geometry. I'll think about that some.

Chris

Chris F

Screw the diagram for a second...

The moment around the center of gravity is always the height of the center of gravity, times the braking force. Simple as that. You can move that force all over along a line adjacent to the ground, and calculate the force perpendicular to a line between that point and the CG, but trigonometry will catch up with you and the distance to the CG times the force perpendicular to the line to the CG are always the same.

Therefore, weight shift is only a factor of braking force and distance of the CG to the ground.

-Chris

MattD@Stoptech

You can reduce the weight transfer by:

-increasing wheelbase
and/or
-lowering cg
and/or
-reducing acceleration

Flux

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by El Pollo Diablo &raquo;</TD></TR><TR><TD CLASS="quote">You can reduce the weight transfer by:

-increasing wheelbase
and/or
-lowering cg
and/or
-reducing acceleration

</TD></TR></TABLE>

Reducing weight transfer is one thing, lets talk about slowing down the rate of transfer...