How to make the 15 handle like its on rails?

[S1Five]

Hello fellow 15 owners,

as i can see from the members spec section i can see a lot of you have quite a bit of handling mods done to your car and i want to know has it significantly improved the handling/control of the car?

These are the specific areas i really want to get to know:
- which mod in terms of handling has most improved the rear end grip or was it a combination of a few items?
- any of you have great track experience and could give me a few pointers in terms of suspension choice, spring rates, tyre choice inc tyre pressure


reason being im so suddenly interested in handling package is, my older bro just bought a mazda rx8 with coilovers and boy does it handle superbly. the car just 'gives' alot of confidence asking you to accelerate out of the corner really early and the stability of it is just awesome and tonight i was just watching him take a u-turn along with my other friends integra dc5r with handling mods also and they both just accelerated out of the corner with no traction issue wot so ever. (note this was in full wet conditions + raining)

my 15 atm in terms of handling is just better tyres, which im running bridgestone S03s all round with 235 front and 255 rear and they are new tyres so tonight i couldnt even try to push to keep up with them. My car on A boost runs about 140rwkw and i really want to sort out my traction/handling charecteristics before i think about using my B boost for tracking purpose.

I hope i can turn this thread into a VERY useful thread for all the S15 owners out there who want their 15 to handle like its on rails. because i certainly do and hopefully we can turn this thread into a reference point for the 15 owners out there who want to start track work.

ps: i hope i can personally add my own opinion to this thread in the future

atm im most likely going to get Tein Flex coilovers in the near future and probably looking into getting some struts at the same time

cheers for any feedback and i apologise for the long thread but im just so motivated to improve the handling of my car

Tony :thumbs:

(btw its 4am here and i didnt re-read my post to check for grammer/spelling!!)

 

[MazzyMan]

My 2cents worth:

- Coilovers a must
- Anti Sway Bars
- Front Custer Adjustable Arms
- Rear Camber Adjusters
- Rear Toe Control Rods
- Replace Pineapples for rear sub frame
- Proper alignment job

With the above I am sure you will get into another dimension of handling!

 

[kieran]

exactly what mazzyman said, they are all without a doubt the things to do, and the most important one at the end a good alignment :thumbs:

 

[S15R]

Good set of tyres

 

[MazzyMan]

Good set of tyres

Now why did i forget about tyres?

 

[S1Five]

Cheers mazzy you been a great help, hope more people can add to this thread with track experience of different suspension setups!

i have one request could i get some simple explaination into wot each of these u mention in real life terms wot it actually does to the car behaviour around a corner or in a straight line


- Anti Sway Bars (this minimises body roll and provide better turn in?)

- Front Custer Adjustable Arms

- Rear Camber Adjusters (i assume this one is just allowin camber to be adjusted for the rear to maximise rear end grip during cornering?

- Rear Toe Control Rods

- Replace Pineapples for rear sub frame

 

[kieran]

you mention track experience alot, but what do you want the car to do, there is again a big difference between fast road set up and fast track? for instance if i wanted more grip on track, loads of neg camber gave me lots of grip, but was shitty on the road

 

[S1Five]

hmm i guess i want to have a more of a neutral balanced car and be able to accelerate out of corners early and to have stability and confidence to try and push

i guess i can say i want more of a road balance for now and later tune for track work

 

[MazzyMan]

Cheers mazzy you been a great help, hope more people can add to this thread with track experience of different suspension setups!

i have one request could i get some simple explaination into wot each of these u mention in real life terms wot it actually does to the car behaviour around a corner or in a straight line


- Anti Sway Bars (this minimises body roll and provide better turn in?)

- Front Custer Adjustable Arms

- Rear Camber Adjusters (i assume this one is just allowin camber to be adjusted for the rear to maximise rear end grip during cornering?

- Rear Toe Control Rods

- Replace Pineapples for rear sub frame

Dude...i am no pro ok...just sharing my experiences (dun kill me if i am wrong):

- Anti Sway Bars = Yes reduces body roll significantly, however pls note that Cusco's rear sway is the same diameter as the original. Some say its the material thats different but for me i'd go for Nismo as the rear is about 1 to 2mm thicker which to me its kinda like makes more sense.

- Front Castor Arms = It allows extending the front wheels further away from the rear thus meaning lengthening the wheel base. In most instance giving the S15 more wheel base length improves overall handling. As it is a case whereby shorter wheel base cars are more snappy at the rear or when it snaps its more unforgiving. For my experience i have extended the castor angle to about 7.25 (original is 6+) and it makes the steering flick back very fast during drifts...but again has a tendency to sometimes generate a very slight understeer. So with this experience it shows clearly that extending the castor angle slows down the rear from wanting to come forward.

- Rear Camber Adjusters = You are right but lets be careful with this...more camber or less purely depends on a couple of factors. Your suspension's character along with the circuit you are in. Example, if you have "a lot" of camber, you would be enjoying good grip in high speed corners whilst suffering less grip on the slower speed corners especially when blasting out of the corner as the rear tyres dun have full contact to the surface. Again, this depends on your suspension, driving line and overall set-up.

- Rear Toe Arm = Stock ones are relying on a big amount of normal rubber bushings which tend to allow more room to move during heavy activity. After market ones reduces the movement significantly thus keeping your toe angle the way it was supposed to be during alignment.

- Pineapples = Very similar to above explanation. These pineapples are aluminum and they reduce sub frame movement during heavy activity...once again keeping the rear nice and tight.

For alignment set up, its about having the rear toe to be set "in" and camber to your desire depending on the application. Front castor angle to be increased slightly from original, slight toe "out" and camber to application. This is more for circuit while for drifting I have my rear’s toe as neutral and very little camber and the front’s toe to be slightly toed out with heavy amounts of camber.

The point here is to minimise any movement from the under carriage as possible, this way you will certainly feel like you are riding on rails. For starters, the coilovers you choose makes a big difference...in fact everything sort of works together or compliments each other so there is always a compromise if you are lack of something or if there is a weak link item amongst them.

BTW...please someone correct me if i am wrong ok. I ain't no pro and just sharing my experiences.

Still learning and experimenting like hell.

 

[A'PEXi]

i think suspension tuning would be different for everyone as everyone's driving characteristics as well as road/track conditions are different, so while not being able to state exact numbers... some form of improvement would be to upgrade some of the standard bits and pieces like others have mentioned.
a good set of tyres is vital for grip, camber on the front made some good improvements to cornering and a rear strut brace caused the car to have a more neutral steer... if you upgrade to a decent set of coilovers, i think the swaybars can be left standard... a too thick/stiff swaybar on the rear would be better suited for drifting...

 

[Nicely]

Piece of concise writing there, Mazzy. Added to Useful Threads :thumbs:

For those wondering. Pineapples are so called due to their resemblance to canned pineapple rings. This is particularly true for Whiteline's bright yellow poly numbers. They are properly called subframe locking collars and come in poly or metal

 

[Topper]

I have all the items suggested bar the Anti roll bars. Rear grip is still not great (235 tires) with the rear breaking away fairly easily in the wet or dry on corner exits. in a straight line, in the dry no problems, in the wet, below 3rd it struggles for grip.

I would say the best thing i've had done is the alignment, there are various opinions on what settings to have, however, i have learnt that it will take a few goes for you to find a setup YOU like, the 1st (and only) setup i've had is ok, but i know now where i want changes.

General rule of thumb - To keep the rear end in line, Toe In is your freind :nod:

Also with coilovers the front camber can be adjusted for your trackdays, then back for the journey home :thumbs:

 

[S1Five]

thx mazzy and all others who have so far replied to this thread, keep em coming!!

topper: how much power are u running atm? btw in relation to power to grip coming out of a corner, is the biggest problem the torque we have which causes the grip to break traction?

so with alignment, is that just making sure all 4 wheels are pointing at a constant/same direction?

to my knowledge, is toe-in when you put your wheels into each other like this? " / \ " of course not that extreme but you get the idea =D


-- just my opinion about the stock S15 suspension
i feel the rear end gets unsettle quite easily. what i mean by this is during a corner the slightest bump will cause the rear to take a leap and it takes a long time for the rear suspension to 'rebound?" back onto the road and during that time when the rear tyres are not contacting is where we lose quite a bit of grip/confidence to the driver to continue accelerating

the car does have a slight tendency to understeer when u initially try to turn in but when you start applying power it smooths out the line you take and eventually lose traction but im not sure if im correct on this but it feels like the car is not in 1 peice, the front end will go in, but it just takes wot feels like a long time before the rear end follows and tucks inside into the line you want - i guess to help solve this would be to have struts?


this is just the feeling the stock s15 suspension gives me, i could be totally wrong but im just going on how i feel when im driving it. or im just a total noob and hav no idea what is going on =)

 

[Yakozan]

^^^
You mean like the rear end feels like it's loose?
I get that sometimes when accelerating hard out of a corner (not break traction hard though)

I've been led to believe it's the design of the rear subframe.
I think it's fitted with 4 bushes to the chassis and allows a pretty good deal of flex. I hope to get rid of it by fitting locking collars to the rear subframe bushes.

 

[Topper]

I couldnt coment on the stock suspension, as i've never been in an S15 with it fitted.

You are correct with the Toe in diagram

As for power, Approx 240bhp at the wheels, the torque plays a big part in traction break, do you have an early model S15? I.e. fitted with a BB turbo? Your mate with the DC5 will have to wait till he gets to 6k/rpm untill any power, yours can be had a 2k/rpm , there lies the difference on corner exit.

 

[S1Five]

yeah but if my friends dc5 can stay in high rev during cornering he will b in powerband already =D

ermm i hav a 2001 audm one not sure which turbo i got as its always conflicting information.

 

[Nicely]

T28 non-BB turbo. Every S15 built after 10/2000 had the non BB. That's all the ADM S15s, I'm afraid

 

[Topper]

I think we just need to be more progressive in our driving than someone with a DC5 who can step on it at all times. For short technical track/corners etc, the DC5 should beat the S15, but on a longer more open track/stretch the S15 should be the faster.

I dont think you will ever be able to set up the S15 so you can stamp on it mid corner and not have the back end loose traction :no:

 

[A'PEXi]

as i said in previous post, try putting in a rear strut brace, made a hell of a difference in my car, reduced the understeer effect

 

[S1Five]

anyone have any good pics of their rear struts and which one they are using?