Road Race Build 2G Auto Time Attack race build!

[TSiAWD666]

Frontline Fabrications makes an aluminum panel for the rear trunk.

 

[EC17PSE]

Well here it is folks! The aerofoil mounts and brackets are complete!

I still need to finish off the supports to stop it flexing side to side and am looking in to some stainless wire setup that some other time attach guys have told me about so that will help keep it strong,

While it looks beefy and it kinda is by design i can always trim it up near the top area but i just wanted it as strong as possible so it may be well over engineered. So as ugly as the mounts seem its there to do a job, as i progress i can play around and get some pointers on holes and making it look a tad neater and better flowing down the line

The lower mounts bolt in to the chassis rails with 4 m12 bolts so thats plenty for its job in hand! Overall i am very happy with how its turned out and will look forward to testing it out in the next month or 2.

 

[EC17PSE]

I also made my a rear tow hook as i require one front and rear for passing tech inspection, simple thick box section and support to stop it twisting when/if used, sits below my exhaust exit and can suport that and my diffuser when i design it

 

[slowwhite]

What are the small things next to your fog lights?

 

[EC17PSE]

What are the small things next to your fog lights?

At the front? They are my side lights, we require side lights in the UK and i wanted these then in the headlight housing

 

[slowwhite]

The small black things next to where the stock fog lights go in this picture.

 

[EC17PSE]

The small black things next to where the stock fog lights go in this picture.

Yeah they are my white side lights, similer to side markers and i still have them in amber but our laws say you must have white or similer color front side lights! Why i dont know since they are not on all the time like DRL's

 

[EC17PSE]

apart from the aero, recently in the last few months i have messed around with the suspension and changed tires and setups, mainly for the worse . Let me explain,

When i bought my coilovers i actually spent 4 months dataing the car and buying very specific rates that matched well when i put them on, and it handled amazingly well!

Recently i just upgraded my springs but did not data it and i have started to ruin its balance! So i swapped from a 12kgF and 8kgR to 14kgF and 12kgR so i jumped up the rear by 4kg due to wanting to stiffen up the rear end!
So now i either drop that down to 10kg or up the fronts to 16kg to balance it out again!

But the fun dont stop there folks!!! Oh no, i changed ride heights aswel! Which messed up all my data too and now i cannot find my data sheet anywhere apart from my roll centers so im going to have to rework it again to get it orecise but it took me months to gather and it was long! So im hoping i can adjust more easily this time so we shall see what happens.

I also swapped rear tires and they was a fail! Not good in the wet! At all!!!

So what does this all mean! Well lets put it kindly, not great handling! Last sunday i nearly crashed the car as the back end let go on me but i mainly blame the tires for that but i know deep down its the whole setup thats the issue!

As i am learning its always altering and recording and its a small step by step process,
But what i recently learned is huge roll center differences front to rear make the car oversteer! And create some not so friendly handling, Well i have pauls lower arms that raise the RC and my rear uppers that i had set for lowering it so they must conflict now since i changed the heights and spring rates! I cannot lower it as i hit speed bumps so i am as low as i can for the road (its not 100% dedicated track car or it will be back to my original height i calculated)

For now i have out it back to oem levels until i rework it all out which will take some time.

What i have added today are front uppers and rear lowers!
Rear lower were ment to have RC adjustment aswel but found out there is a washer spot welded in the inside of the subframe so i have out that on hold till i find a way to do it, i am thinking of thin washers inbetween the rodend standoffs and the 3mm plates outside will also strengthen the frame so it might still be possible, it may help with the uppers tame full advantage a bit more!

The front uppers i have set to as close as i can today and will finish tomorrow and final adjustment and alighnment and bumpsteer re adjust and see how the test drive goes,
I set it up for 2* rear camber and 2.5* front with front caster being 6.6* now. RC and anti dive are all set to oem for now to keep it more simple!

 

[EC17PSE]

So testing went kinda well, i realised today i been doing my alignments all wrong .

Figured out i was not completing the alignment completly what i was doing was, i set the rear toe and then align that to the front wheels to make sure it dont crab, and when i did the fronts i just set toe and thats it!.what i found out today is i also have to set the fronts to the rear also to keep it all in 1 line! And boy i am glad i found this out as its much nicer now. Braking is much nicer and in a straight line which is helpful as before it did oull a bit and felt a tad off and not as strong as it once was! I found the issue! Yay.

My feedback so far on the arms can be found on my suspension thread.

On to my overtseer issue, i swapped tires back to my Sessantas and it has helped but not completely so i started to go back and see what i altered and when in relation to upgrades/parts swapping. I already had an amazing setup so i know its something i did most recent! And as listed above i only messed with ride heights, springs, rebound, tires, thats all i think i messed around with, oh and my BS kit but that certainly is not the issue here.

I think it does have some kind of relaion to front and rear something! WHAT EXACTLY I AM NOT SURE JUST YET!!! My research shows its possibly front to resr Roll centers and i will play around with this and see the effects.

I also may consider upping the front spring rates to match the progression of the rears and rule that out as i skipped 1 set up front (why i dont know) im learning still dont forget. Its not easy and i see why it can take years and people give up on learning this stuff!

After all this i had a ding ding moment!!! Yes i have them sometimes haha. So i decided to read up on it and i believe it is now related to the spring/rebound setup as I did alter them together,
I used to run more rebound in the front and less in the rear, but when i did the swaps i was under the impression more rear rebound was better and research told me this is wrong and it unsettles the rear and creates oversteer because the rear is always jumping and darting around so it comes down to mid corner setup or thats what i read anyway,

I put the front rebound higher then the rears now but i ran out of time for a test drive so i shall do that next weekend and see if i can get rhe balance right using this method! Or at least better and then i may need to consider the front spring rate to get my balanace back again. We shall see.

Alot more research in the mean time will help me narrow it down i hope so i can look at specific alterations/adjustments to make to rule out.

 

[EC17PSE]

Over the last 2 weekends I have been with the car all the time! and when I am not I have been reading ALOT on suspension setups and causes/fixes to resolve my issues I had been having since i messed with the suspension!

Finally I can say I have now fixed 90% of the issues!!!!!!!!!!!!!!! YAY.

recap of the issues were when cornering i was getting a slight jumping and the rear washed out on me and i could not swerve a bit of the rear sweeps around abruptly! it also nearly totalled my car in the rain a few weekends ago. I had new tires on aswel and still think it was partly there fault, maybe not

today I have pretty much solved all of these issues with alot of hard work, redoing and time setting up and then resetting up time after time, bump steer test after test, small adjustments here and there and a test drive to feel its effects and so on. oh and did I mention alot of reading!

firstly before i started i set my rebound back to higher at the front then the rear! this is how it is meant to be and a good reason for my issues to begin with but its not as simple as that as I shall explain in this long winded reply! so bear with me but it is interesting and very mind boggling indeed.

when I started all this stuff I set front bump-steer as close to zero as my kit allowed me to as I read it was best to have zero or as close to it and........... I assumed! yes assumed this was the same for the rear but recently found it its far from it! its the total opposite in fact believe it or not.
so in the rear in a turn under compression AKA (jounce) you want the rear outside wheel to toe in to turn into the corner but not too much and not too little! so its a great game to play around with because not only that the other side is doing the opposite and toeing out inside wheel under decompression AKA (bounce) but while you set this up for corners you have straight line and braking to consider! this is where it gets tricky! and mine does need small adjustment for this and only this now!

I will adjust slight toe i on the rear at static so it gains me better straight line stability and hope it helps a bit with breaking but at the moment its not uncontrollable when breaking when hard but its noticeable s small adjustment should help put greatly I think.

I have set the rear of the car up with zero toe at static but under cornering i gain 0*55' of toe in under compression and 0*40' with decompression so it very much turns into the corner now! before my setting was very low! just 0*20' toe in and 0*10' toe out so that low combined with the tires slip angle is what made my rear slip around the corners and create over steer! I am very happy how it handles now and I am very much confident once again of its performance and handling! I will of course keep n eye on it and tweet bits to see if i cam make it that small amount better but its hard work and small adjustments can go backwards and takes time to get perfect! but now I have all my own tools I can pursue this and continue to make it the best it can be with what it has.





FOR DATE USE ONLY, I took all BS readings from my rear toe kit (pauls arms) it may be useful data but remember ride heights also play a part in the readings too so this is not what works for me will work for you as I am not saying it will but you will see the difference it produced for me at each level! but its a guidance only

I will list all data from the gauge and convert them to MM and also what it relates to in degrees and degrees are listed in * for degree's and ' for minutes. It was also measured over a 1.5" each way motion from 0!

ROD END AT TOP OF THE BS KIT (closest to the knuckles arm)
Compression 100 thou / 2.54 mm / 0*20' TOE IN
Decompression 50 thou / 1.27 mm / 0*10' TOE OUT

ROD END IN THE MIDDLE OF THE BS KIT
Compression 170 thou / 4.31 mm / 0*34' TOE IN
Decompression 130 thou / 3.3 mm / 0*26' TOE OUT

ROD END AT THE BOTTOM OF THE BS KIT
Compression 270 thou / 6.85 mm / 0*55' TOE IN
Decompression 200 thou / 5 mm / 0*41' TOE OUT

so with this data I received I opted for the max toe in/out I could get with cornering. once I adjust toe in on the rear i will gain more toe in on compression and toe out under decompression, I hope i can balance it out to keep both cornering and braking/straight line handling happy! time will tell

 

[Black95TSIawd]

When making a run... I lower my rear rebound and it gets more stable out back. If I need a little more, I set rear tire pressure a half to 1 psi lower. Works everytime. I run 14.5k front/10k rear springs. Front rebound is maxed out and rear is about half on koni yellows. Rear toe in .01 so basically zero.

Great data and thanks for sharing.

 

[EC17PSE]

When making a run... I lower my rear rebound and it gets more stable out back. If I need a little more, I set rear tire pressure a half to 1 psi lower. Works everytime. I run 14.5k front/10k rear springs. Front rebound is maxed out and rear is about half on koni yellows. Rear toe in .01 so basically zero.

Great data and thanks for sharing.

Yeah i certainly agree that rear rebound lower is better! I used to have it this way and i assume too much but reading all these forums and so on has really helped me understand it alot more! Just hard to piece it together with the whole thing in motion and so much else going on in that same motion!. Fun to learn though.

Im not maxed out on front yet so i still have room to play if i need to with that, but the balance so far good.
I need a tad more rear toe in for straight line stability but a small amount should be good enougb without wiping alot out all the toe out under decompression in a corner,

 

[Black95TSIawd]

The tires (level of grip) is what determines initial settings. Last year, on 245 tires, I probably had too much spring. Front rebound was wayy down and full soft in the rear. Otherwise it would understeer and then snap oversteer without careful driving.

And yes, tuning a motor is easier than tuning suspension. It took me a year of constant autocrossing and making changes and even now, i'm sure i've only touched the tip of the iceburg.

 

[EC17PSE]

The tires (level of grip) is what determines initial settings. Last year, on 245 tires, I probably had too much spring. Front rebound was wayy down and full soft in the rear. Otherwise it would understeer and then snap oversteer without careful driving.

It certainly does help towards it, my issue was not mainly tires but it didnt help my issue either. Mine was more setup more then anything,

I use a split setup, so a 245 front and 255 rear with a wider rear track, but i will be going up to a 255 up front when my tires wear out,

Since i have adjusted camber and caster i now seem to find the tires squeal a bit more then before, but it still holds really well a d i think its related to slip angles being oroduced but yet to work out how its been adjusted from before so its next on my list to work out

 

[EC17PSE]

Did some more adjusting today, I now believe i have 100% figured out my issue or what it causing it! I need to modify my rear subframe to allow the lower arms inner mounting to go up higher! This is because the fro t to rear centers are out of balance causing excess roll to make it loose at the rear end! Let me explain a bit more,

All cars have a roll center they set and moves during cornering, when i lowered my car it messes with said centers and while on stock suspension arms it would alter the same in theory, because i have pauls front lower arms that raise the front center again and i dont have such joys at the back as the 1 that needs to be adjustable is the rear lower! It has a much bigger effect on the center overall! The uppers do aswel just not as much! This needs the lowers to be adjusted! But its not as simple as that as camber static and dynamic comes into play aswel as toe! So this is what i am up against when learning all this!

So i have 2 choices!! Remove pauls arms or modify my rear subframe! And i choose the rear subframe as it was in my original plans and when i drew all my motions this was why i wanted to include this! Since pauls arms raise the RC i have to speed the rear up and that means raise the rear RC!

This should allow me to raise the lower arms inboard pickup point and bring it back into spec for the centers and keep front to rear roll in balance! Its the only logical way i see now as i have done and adjusted just about everything else going i can adjust!

More data

On another note i considered using my front BS kit to give me toe in/out under braking and cornering but j decided to just keep it as simple for now! By my figures are below,

Thin spacer below the rod end gave me.
Compression 5 thou / 0.12 mm / 0*1' of toe in
Decompression 23 thou / 0.58 mm / 0*4' of toe in.

Thick spacer beloe the rod end gave me.
Compression 48 thou / 1.21 mm / 0*10' of toe out
Decompression 22 thou / 0.55 mm / 0*4' of toe in.

So if i used the thick spacer it would be good for cornering and braking but i dont k ow its effect in straight line driving over bumps! So for that reason i kept it simple and kept the thin washer below and opted for the toe in under braking and cornering since toe in makes the front end turn a bit faster since the loaded tire in a corner is ready pointing into the corner and not having to go past zero to point but its often known toe out is faster cornering but its not, so because of this knowledge i have come to find out toe in for me it is!

Rear i have adjusted to not give me so much toe in cornering as it felt too much so i went back into the middle now,

Another test today was how much camber i personally gained and lost in compression and decompression! This is very interesting! As it makes me look at the whole static camber this alot differently now then before! Again indid these tests over a distance of 1.5" each way!!!

Rear was pretty much the same, i gained and lost 0*30' of camber each way, so if i started with - 1*30' (-1.5 degrees) of camber under compression it would go to 2* of camber and 1* of camber under decompression!

Front was a bit different each way but not by much. I gained 1* on compression and just under 1* on decompression! I currently have -2.5 camber up front and i think i will drop this down to 2* now because i feel as if i will be loosing grip in a corner while gaining such amounts of camber in compression. This may mean i can stop the tires from squeeling as it never squeeled so much while cornering since i went and added fair amount of camber!

Thats about all i got done today! Apart from a test drive where its now much nicer to driver once again aoart from the roll center balance issue

 

[Black95TSIawd]

Our setups probably differ quite a bit, autoX vs road racing, but more negative camber is good. -2 degrees is pretty low and I can feel the loss of grip in the corners. Tires screeching means nothing. Slicks barely make any noise.

You'd have to drive the card very hard (harder than you imagine on public roads) and read the tire temperature (inner, center, outer) and then determine if you're running too much or not enough camber. Generally speaking, more negative = more grip.

I don't really care too much about tire wear during daily driving, but even with -3* plus of camber, the outside half of my tires wear out quicker.

 

[EC17PSE]

Our setups probably differ quite a bit, autoX vs road racing, but more negative camber is good. -2 degrees is pretty low and I can feel the loss of grip in the corners. Tires screeching means nothing. Slicks barely make any noise.

You'd have to drive the card very hard (harder than you imagine on public roads) and read the tire temperature (inner, center, outer) and then determine if you're running too much or not enough camber. Generally speaking, more negative = more grip.

I don't really care too much about tire wear during daily driving, but even with -3* plus of camber, the outside half of my tires wear out quicker.

.
It is different and research does show it should give more grip and i will get a temp tester and get checking on the temps, i plan to do a test day at a track once my seat rails are made and harnesses are in so i can get better data from tires and setup from there.

Im just more concered i gain 1* of camber under load! I just hope its using it wisely and getting contact patch down as to keeping on the inside of the tire and same goes to the tire on decompression and if its gaining that camber and putting it down ok to give a bit more tread area on the ground! We shall see soon hopefully

 

[Black95TSIawd]

Oh please do share. Loving all this numbers and knowledge you're giving out.

 

[EC17PSE]

Oh please do share. Loving all this numbers and knowledge you're giving out.

Well i am trying my best to learn this all, so i am just sharing what what i find when i find it so it may help the group or not, its certainly helping me as i progress

 

[EC17PSE]

Another day and other modification!

This time i modified my rear subframe, the reason is to allow mh rear lower arms to be moved up 1" on the inner mounting side, currently i was pointing down towards the center of the car, this made my rear RC way below ground, now i have adjusted it up im at a slight angle towards the outside of the car now,

This has made the car alot different! Its so sharp now kinda like before but this seems different! Its so responsive, the rear if very quick to react and i seem to have made the rear as fast as the front which is good, before it was slower and lagging but im happy its reacting fast.

I am currently holding the bracket in with lower bolts aswel as i have not yet welded the bracket but its not going anywhere as it locates it perfectly,

 

[Black95TSIawd]

Wish thats was legal for me to do. Although I dont think my car is as low as yours and my arms are pretty flat.

 

[EC17PSE]

Wish thats was legal for me to do. Although I dont think my car is as low as yours and my arms are pretty flat.

Yeah im working around my ride height so i had to and im pretty free on stuff like this in my series i wanna join, so thats good news for me, gonna prep for my tubeular subframe jig soon.

 

[Black95TSIawd]

Yeah im working around my ride height so i had to and im pretty free on stuff like this in my series i wanna join, so thats good news for me, gonna prep for my tubeular subframe jig soon.

If anything, you're proving all the original DSM racer's point about not over lowering the car. Tip my hat off to you for trying stuff out of the box!

 

[EC17PSE]

If anything, you're proving all the original DSM racer's point about not over lowering the car. Tip my hat off to you for trying stuff out of the box!

Yes i read many posts saying over lowering can create issues! It would not be as bad if i kept the stock front lower arms, but as i have pauls it throws the whole front to rear balance out of whack! So i had to do something to match the front setup!

While some may see it as drastic i see it as an advantage! Ive kept lower CofG, while i may be stubborn and could have gone another way (raising the car) i wanted to defeat the side effects of lowering our cars past its optimum point and gain control once again!

A nice subframe will work wonders, im just wondering if i can make it have wider range of adjustment, like up and down but in an out aswel, may not work well but some GT cars have multiple mounting holes to take use of

 

[EC17PSE]

Just collecting some parts lately!

All my new timing components and new kevlar RED belts are in, i need to do it as its been about 5 years now plus i have a leak in my front balance shaft seal as it did it last time and i clearly did not get the seal right!

My new light blue Iridium visor came in which looks awesome! I may get the dark blue Iridium if i feel the need for a darker shade!

Also my new Hans by Schroth arrived too! Since we have to use these now in all forms of motorsport here. Without it you cannot take part!

Next is my race suit to be ordered and the rest of the kit Gloves, Shoes, undersuit! Then thats the safety side of things done and ready which i will order that all this month no doubt as it take a few weeks for my modification to be done anyway.