doomsdaydonkey

Hi,

I'm not looking at a drag car but understand some fundamentals about traction...

I'm considering looking at the Hotchkis springs as they are slightly softer in the rear and harder in the front, the adds say its about 12% whatever transfer to the front.... do you think it will aid with launching better than OEM and assist with weight transfer to the back....

I drive this car on the road so its not a race/drag... although the interior is stripped out and currently getting redone nice style!

another thing, am thinking of moving the battery to the back... thats about 16kgs of mass from the front to the back... anyone done this kinda stuff...

another thing i did was get a really soft compound tire, am currently running 325 michelin pilot sport cups, they are 80 AA...

and yea, i got the racelogic traction control unit as well...

all in all I want great pull off/acceleration in 1st, 2nd gears on my 500whp build...

Lets make friends and share the info...

Cheers
DDD

davidv

iTrader: (2)

I do not see the point for a daily driver but if it suits your needs do it.

BTW the damper not the spring prevents the front of the car from rising during acceleration.

doomsdaydonkey

with a weight transfer i am presuming the front should rise or the back drop slightly bogging down in order to get maximum benefit.

scotts300

iTrader: (46)

Disconnect the front sway bar when you do go drag racing. Get a DA set of shocks so you can control and and rear rebound and compression. Michelin PS Cups are not a drag tire, so you will still likely haze the rear tires when you launch with 500rwhp, even in a 325. The PS Cup is a soft compound, but that tire still has a very small sidewall (325/30/19 = 3.8" sidewall all around). For all the $ you have in the car, get yourself a cheap set of 16 or 17" wheels with some ET Street tires if you want to make a good 1/4 mile pass. The PS Cups should be fine on the street, though I think the Toyo R888 is a MUCH better tire (and comes in 19" sizes).

davidv

iTrader: (2)

That is the suspension theory for drag racing. Flexible dampers or none in front to get the front end up. Strong springs or solid springs in rear to transfer weight immediately over rear wheels.

johnlotusboy

iTrader: (1)

For a street car get an after market limited slip differential, run low camber(-1.1 to -1.3), get adjustable rebound shocks for the front and run the shocks on soft setting.

doomsdaydonkey

thank you for the advice, I am looking at making the ultimate road car, which implies handling is sound, launch to 100kms under 4 seconds and all the great stuff the guys spend the $$$ on for the super cars... this project was to make ma own super car, the one that beats down otha super cars...

so... from the advice so far... a soft rear is a good thing to aid in weight transfer... relocation of the battery to the rear, thats 16 kg's going from the front to the back... the nissan racing team here weild a little box just behind the diff, so its nice and now... 32 kg in total transfer, a limited slip diff... I have a nismo 2 way so am sorted there... nice soft rubber compound tires, the side walls were mentioned, the 325/30/19's are nice but am thinking of widening to a 345... michelin have one but the side wall is 30, pirelli have one, its got a softer compound 60 and the side wall is 35... will def fill the gaps between the fendors at the back... i had my fendors custom made, they are cf and follow the natural lines of the car so the 325's are still a bit inset and could use an inch on the outside...

a concern with a larger tire is that once u WOT in 4th gear, the back end can start to wobble a bit and this is f*in scary... found this out cause I had 2.5 inch spacers on the back previously, the made a big wobble, took them off to solve the issue... just hope another inch of widening the rim will not give us the wobble...

the springs on the rear, I'm confused... r u saying that one needs harder springs or softer springs in the rear for better traction..? the hotchiks r softer in the rear than OEM and claim better traction..>?

I've decided to make mods till i attain my goal with v-box test results... if you guys would like to help me on this journey it will be most appreciated... and yea we can all learn and share the info...

cheers
DDD

doomsdaydonkey

an update...

I got my guys to cut a whole in the back of the z and drop the battery in it, the standard battery, its a weight transfer of minus 16 kgs off the front and plus about 20 in the back, including custom box and re-inforcement for the battery. this is a total of about 36 kg's weight transfer to the back of the z.

I must say that it does make a difference and can feel better traction off the line, granted that the racelogic has been tuned a bit as well... pics to follow shortly. am thinking of getting 345 michelin cups on the back to replace my 325's on at the moment...

betamotorsports

iTrader: (1)

Instead if disconnecting the front anti-roll bar, run one with a small diameter. If you get out of shape down track a front anti-roll bar can keep you off the wall.

And remember, shocks only control the rate of load transfer. They have no affect on the total amount of load transfer.

Gsedan35

iTrader: (10)

I do not get into drag suspension, so I won't suggest right or wrong

At 330lbs vs 342lbs (ok 350lbs if we use Hotchkis's number), your not talking about much of a differance. 139lbs seen at the rear wheel vs 147lbs if we use the Hotchkis oem number. Hotchkis did make the spring softer then oem, but I don't think it was ment for added traction in standing starts, mainly for the slalom and coming off corners, allowing you to roll into the throttole sooner as cornering loads eased.

You could use the rear springs out of the Tein S-tech ment for the G35 coupe, you'd get about a .4" drop and a milder 274lbs rate or 115lbs at the wheel.

of course the ultimate thing to do is go with the SPL rear mid link and experiment with different rear spring rates.

doomsdaydonkey

Thank you for that input, after doing some research it looks like the guys tend to keep the back as solid as possible to insure that under a hard launch the angles of everything, tire, diff, subframe all stay pretty much the same insuring a steady contact patch for the tyre....

I was looking into some of the spl stuff, am thinking of using a kw v3 suspension which would allow me to use the spl toe arm that replaces the spring bucket... not sure what a traction arm is though kentix is selling this kit...?

http://www.importpartspro.com/kirafrcareca.html

kind regards,
ddd