loffe

hi! I´m interested to know if you guys have advanced technical know how about the Group a cars that was such a success in the 90 s. Its more and more popular to build a nice time attack car, and the "top secret" know how maybee not so top secret anymore?? I think it would be very nice to know more about hardcore technical solutions, data about suspension alighments, CG, RC, scrub, spring hardness, swaybars and so on, all this information would be alot help to people today trying to show the world about the GTRs splended performance. i´m also interested in engine tech, such as the swing oil pickup in the wet sump and so on, all this Group a candy.. I know there is a group a thread but its mostly just alot of talk about anything group a. /Lofa

ok, thanks for your input, i will try to find some way to figure out the CG and go from there.

i´m having it cornerweighted when i think i´m close to what i think is final solution

do you think its a good way, if i make the inner lower adjustible, so i can adjust it maybee from RC80-RC180. At other places i have read it is very extreme to have such high RC that is so close to CG I think you are totaly right, i should find out what my CG really is. here is an interesting comparison ive found on another cite: Now we may have 4 basic positions: 1) Roll center height (from now on RCH) = center of gravity (CoG) No pivoting here, it means that there is no roll. Its like trying to spin a door applying force in the hinge. The car is turning, lateral force is applied, but there is no roll. Hence, all the force is "catched" by the wishbones. This makes the car as hard as a rock, as spring/dampers doesnt work here. Its good for nothing. 2) RCH between CoG and the ground. Depending the percentage of that height you distribute how much force goes through the wishbones and how much through the spring/dampers. The range between 15% and 30% of RCH compared to CoG is the most common place to locate it in many racing cars. 3) RCH = ground height. All the lateral forces passes from the chasis to the wheels throught dampers/springs, so virtually the wishbones makes no force under pure lateral load condition. 4) RCH below ground. More force than whats actually transferred passes through the spring/dampers, so that the wishbones is loaded unders "a negative" force. This means outer top wishbone for example is not under compresion, but under traction. This is the case of tourism racing cars that have to maintain the suspension geometry from the original street car when you reduce their ride height, there you have to find the best compromise between what you gain from aero and reduced CoG height and what you loose for poor suspension geometry. Here you dont have jacking, but the contrary. Also it is the case of heavily "tuned" street cars... puaj!!!... .

This is how my car looks like today Today setup RC 33 i´m thinking of raising inner lower link 20mm, then it would be like this Next step? RC 96 What do you think?

Its just casim. The CG is just set from a quess. The simulation i did with original spec, problem is i don´t know factory car hight, i maesured on my car and it wasn´t original hight from start, so if i make it higher than on calculation it raises the Roll centre. Good tip, i can try and see what happens if i goo back, so i try to get 80mm RC. CG of 170 sounds very low? But maybee it isnt so important, i don´t have a factory spec car any way, it was just to give a view in what happens in an easy to see way, for those who doesn´t can visualize that in mind. I do the calculations just to compare, what happens, i have not made it together with rear end, that i can not do, have to try it on road instead.

Youre right Risking, it was bad data, i have found my original data now and see some foults. Except from those faults.. One measure that i dont have is original hight on inner lower mount from ground, does anybody know hight? Do you think this look better? GTR org setup Roll

Hi I made this calculations today. To be honest i have played a little with the data (just like the meteorologists ) and i can have put some of the data wrong when i have changed back, i havent controlled that yet, therefore i wrote close to original setup. Which data do you think is wrong? On my car i have RC distance with camber increased under spindle, i have raised upper inner linkmount 25mm. i have shortened upper link. i have shortened hight on spindlearm. trackwith is 1618mm camber 4º caster 7º (somewher close to) I have calculations on that to, but on my other computor. In this ridehight i have 6cm workingdistance inwards and 4cm outwards on coilover. I´m not an expert, i have this as my hoby, but i would like to get better. /christofer

maybe this can help a bit Here is a picture of close to original setup under roll condition Then we lower the car 40mm and see what happens and make the roll You can see that the upper-outer link probably is close to bottum out and that the rollcentre is way off, just looking at the geometry makes it easy to understand that it needs a lower force to make it roll when susp-arms stand angeled up right from the beginning. Then you have to test your coilovers workingdistans without feathers to see it can move up and down as it should, not so nice to ride with coils bottum out at bumpstops. Maybe it looks cool with a lowered car, but its worthless without setting things up properly i think. And this is with only 40mm lowering.

If its real race öhlins you are after i would contact ohlins sweden directly and ask for their opinion. [email protected]

What 4wd controller do they use?

I think its easy welding Titanium, don´t forget shielding gas, or it will crack very soon. A good thing to know is that titanium has a very high meltingpoint (1725ºC), but it oxidixes already in 500ºC in atmospere and becomes a white powder..

Interesting thread, i´m doing almost the same mods on my r32. Nice to see that i think in the same way, then it should work i guess...

If you read the wire schematics, then you see the abs-sensors input is 13,14,15,16,17,18,19 and 20 in the E-TS control module. Then it has 3 pin out to activate abs soleniods, 10 FL, 6 FR and 9 Rear and they use the same signalground or is it +12?? nr 7. Pin nr 5 activates motorrelay on ABS. So if i understand it right E-TS does something with signal to add the rear ones to one outsignal? I was thinking of convert to 4way Bosch 5.3 EBD ABS but i stopped myself until i understand if E-TS needs signal input from wheelsensors, otherway i´m thinking of remove them from E-TS and connect to Bosch 5.3 module instead. If ABS and Atessa is separate in E-ts module would be great, then its just to disconnect the in and out pins that has with ABS to do. What is your input?

ok, thanks!