Looking for input from Evo members with significant setup experience
Jul 15, 2010, 03:54 PM
#106
Thought your car was like 2900lbs? Mine was 3240 at G2 if I recall...and it has probably 50lbs in sound deadening and speakers I've installed. Is that weight ballasted with you in the car? I'll have to look at my sheet but I don't believe I had any corner above 1000lbs.
Last edited by dbsears; Jul 15, 2010 at 03:59 PM.
Jul 15, 2010, 05:02 PM
#107
There's more weight still in the car. The whole exhaust is still on, the AC is still in, and the evap canister is still on.
I'll let you assume the math.
I'm contemplating shaving 335/30/18's on some 18x12 wheels...and putting some 295/30/18's out back.
I'll let you assume the math.
I'm contemplating shaving 335/30/18's on some 18x12 wheels...and putting some 295/30/18's out back.
Jul 16, 2010, 07:32 AM
#110
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Jul 16, 2010, 07:40 AM
#111
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I've been going through my calculations with matt...
IIRC
Front
10k spring = 560#
980 lb corner weight
120 lb unsprung weight
860 lb sprung corner weight
560*0.94*0.94 = 495
860/495 = 1.74" per g of cornering
Track width in the front ~ 62"
tan-1(1.74/(62/2))) = 3.3 degrees of body roll per G
If you translate that to 1.2 or 1.3g's assume its a linear extrapolation... 4.3 degrees @ 1.3g's !!!!
....
I've been going through my calculations with matt...
IIRC
Front
10k spring = 560#
980 lb corner weight
120 lb unsprung weight
860 lb sprung corner weight
560*0.94*0.94 = 495
860/495 = 1.74" per g of cornering
Track width in the front ~ 62"
tan-1(1.74/(62/2))) = 3.3 degrees of body roll per G
If you translate that to 1.2 or 1.3g's assume its a linear extrapolation... 4.3 degrees @ 1.3g's !!!!
....
- Assuming a linear spring compression rate, then in Ernie's example at 1.3g's there would be 2.26" of movement. When I look at the amount of travel on my Swift Spec-R setup, that much movement puts me well onto the bump stops (there's maybe .75" of movement before the bump stops), so how much more room for suspension travel is there on the coilovers?
- How much spring rate do the stock front and rear swaybars add?
l8r)
Jul 16, 2010, 07:58 AM
#112
Thanks for posting this kind of stuff. After looking at this, I have a couple of questions:
- Assuming a linear spring compression rate, then in Ernie's example at 1.3g's there would be 2.26" of movement. When I look at the amount of travel on my Swift Spec-R setup, that much movement puts me well onto the bump stops (there's maybe .75" of movement before the bump stops), so how much more room for suspension travel is there on the coilovers?
- How much spring rate do the stock front and rear swaybars add?
l8r)
- Assuming a linear spring compression rate, then in Ernie's example at 1.3g's there would be 2.26" of movement. When I look at the amount of travel on my Swift Spec-R setup, that much movement puts me well onto the bump stops (there's maybe .75" of movement before the bump stops), so how much more room for suspension travel is there on the coilovers?
- How much spring rate do the stock front and rear swaybars add?
l8r)
question #2... There are ways to calculate this completely based on theory...and then you can also measure it via droop and jacking the car up. I'll be doing both after the race and comparing the results...as well as comparing what's on the market.
My equation above only takes into account the coilover spring, not the spring from the ARBs, the chassis spring rate, the tire spring rate, spring rate of the bushings, etc. They all add up. Not to mention we're assuming that we're cornering on a completely flat smooth surface.
Everything is sorted and ready to go for the race today.
I made my personal packing list, schedule, and checklists last night... time to execute.
8:00 Leave
11:00 Arrive @ Drift Office
11:30 start making dyno pulls
12:30 finish + refill 114L
1:30 finish lunch
2:30 show up at Track and setup
3:30 swap wheels and set tire pressures
5:00 Qualify
6:00 Heat 1
7:00 Heat 2
8:00 Heat 3
9:00 Awards ceremonies.
We're going for 1st with Scott driving. I think its very doable. I'd like to be able to finish 2nd, but we'll see how capable I am today as a driver. Best I can do is put a winner on the trailer!
-Eric
Jul 17, 2010, 11:59 AM
#114
Ok so the track event went well! We were .3 of a second off our target. Scott ran a best of a 1:09.8! That would be good enough to have set the lap record the last event!
However we're chasing a moving target.
The lap record was reset several times this last event. The one that was not touched was the 1:06.6 set by an Ariel Atom on 275 Hoosier A6's!
The GTR we competed against in the AWD class had NEW (I mean stickers on them) 315 Hoosier A6's. Dietz ran a best of a 1:08.4 IIRC and the owner of the car only beat our (Scott driving) combined time by four tenths. So we were very close to a 2nd place finish, but ended up getting 3rd.
We were going on a few assumptions.
#1) Dietz would not be able to drive a car that weighed 600 pounds more than his c5 z06 (that he's driven for 6 years) faster on the same size tires. Evidently Physics doesn't apply to the R35.
#2) The A6's would not be able to take the hot lapping. They didn't shine, but they didn't flop.
#3) By running faster than the previous lap record...we would undoubtedly win.
I was wrong on all three accounts. I guess that's racing for you
*****
Notes from the event
New to the car for the event...
ACD reflash from Gruppe-S
Ti shims from girodisc
Fresh RBF600 fluid and not the ATE blue
-100 pounds
+50 hp from 3k to 8k I took the car to the dyno before the event. Put down 400lb ft and 370whp. Not bad for a TBE, filter, and a magnus v5
less camber in the rear...an RCH of toe out in the rear
less toe out in the front
Our target lap time in the CCW direction was 1:09.5
The car rotates on lift throttle AND on trail braking. Its very nice. I attribute this to the camber and toe changes. I think we have a fair balance at this point...it worked well and was predictable.
the ACD reflash definitely sent power to the rear wheels. We were doing burnouts with the inside rear tire leaving fatty 1 tire fire lines all over the course. So naturally we're still picking up the inside rear tire mid corner. I feel that car had more a tendency to pick up the inside rear this time, than compared to others. I can't really attribute any change we made to that, but I think we just expected to be able to get on power sooner.
The solution here is the TRE rear diff and putting that tire on the ground. More on this later.
Another issue that peaked its head during the first heat...the brakes got soft. Not like boiled fluid...just soft... all the time. We both scratched our heads knowing that we had freshly bled RBF600 in the car...WITH the Ti shims. We both said... well we're not boiling the fluid and the brakes are always there. We'll inspect later. I inspected in better lighting. The slotted rotors I once had are no more. I think we're past the minimum wear on these things.
Solution? 2 piece Girodisc front rotors And maybe some SS brake lines.
Back to the issue of picking up the inside rear tire. I see two issues.
#1 Center of Gravity
#2 damping/spring rate
Possible solutions
Buy Ohlin's DFV's might have to break out the CC for this one!
OR
Buy a 14-15k Hyperco spring and test 12k front 15k rear
play with the rear bar
If I can get the spring rate to resist roll...i can run less static camber and have a better contact patch under braking! win win!
AND
Work on reducing front weight
strut tower bar -> Carbing?
Lower/move mini battery
Move ACD pump to rear of car
Remove AC
lighten subframe braces and fasteners
lighten engine mounts
light weight o2 housing
light weight manifold
lower the seat and driver
lighten the subframe brace (like Buschur's setup)
Mostly focusing on removing weight from the front of the car...and removing/moving weight from high points to lower points.
If I can drop 100 pounds off the front end of the car... my front tires will love me.
Things to buy
TRE rear diff ~450 shipped
Girodisc 2pc Fronts ~ 750
Girodisc brake lines ~ 100?
Hyperco springs ~ 140
FP Green ~ 250 (forgot to mention this haha)
Total 1690.00 before lightweight parts or possibly Ohlins lol.
Alignment 60
Racegas 50
Pump gas 40
Registration 85
Dyno time 90
Another 325 for setup... I'll be spending ~2015.00 before the next race. :/ I guess its time to get into the garage and start Fabricating some dope parts lol.
Like I told John Mueller after he told me that I just needed "buck up to play with the big boys" I explained it wasn't in the budget. I want to race for the rest of the year... not just do well at one event and then pay off my Ohlins over the course of the winter lol.
Hopefully the car performs appreciably better next time out and doesn't consume parts or require a bunch of changes. Then we might be looking at buying some killer shocks for the final Event in September.
BTW! got some minty Fresh R6's on the way so I'll be selling my current set of 285/30/18's!
Question for anyone reading this... HOW DO YOU SUGGEST I GET THE INSIDE REAR TIRE ON THE GROUND (besides removing the rear bar and going to 8k springs in the rear)
However we're chasing a moving target.
The lap record was reset several times this last event. The one that was not touched was the 1:06.6 set by an Ariel Atom on 275 Hoosier A6's!
The GTR we competed against in the AWD class had NEW (I mean stickers on them) 315 Hoosier A6's. Dietz ran a best of a 1:08.4 IIRC and the owner of the car only beat our (Scott driving) combined time by four tenths. So we were very close to a 2nd place finish, but ended up getting 3rd.
We were going on a few assumptions.
#1) Dietz would not be able to drive a car that weighed 600 pounds more than his c5 z06 (that he's driven for 6 years) faster on the same size tires. Evidently Physics doesn't apply to the R35.
#2) The A6's would not be able to take the hot lapping. They didn't shine, but they didn't flop.
#3) By running faster than the previous lap record...we would undoubtedly win.
I was wrong on all three accounts. I guess that's racing for you
*****
Notes from the event
New to the car for the event...
ACD reflash from Gruppe-S
Ti shims from girodisc
Fresh RBF600 fluid and not the ATE blue
-100 pounds
+50 hp from 3k to 8k I took the car to the dyno before the event. Put down 400lb ft and 370whp. Not bad for a TBE, filter, and a magnus v5
less camber in the rear...an RCH of toe out in the rear
less toe out in the front
Our target lap time in the CCW direction was 1:09.5
The car rotates on lift throttle AND on trail braking. Its very nice. I attribute this to the camber and toe changes. I think we have a fair balance at this point...it worked well and was predictable.
the ACD reflash definitely sent power to the rear wheels. We were doing burnouts with the inside rear tire leaving fatty 1 tire fire lines all over the course. So naturally we're still picking up the inside rear tire mid corner. I feel that car had more a tendency to pick up the inside rear this time, than compared to others. I can't really attribute any change we made to that, but I think we just expected to be able to get on power sooner.
The solution here is the TRE rear diff and putting that tire on the ground. More on this later.
Another issue that peaked its head during the first heat...the brakes got soft. Not like boiled fluid...just soft... all the time. We both scratched our heads knowing that we had freshly bled RBF600 in the car...WITH the Ti shims. We both said... well we're not boiling the fluid and the brakes are always there. We'll inspect later.
I inspected in better lighting. The slotted rotors I once had are no more. I think we're past the minimum wear on these things. Solution? 2 piece Girodisc front rotors
And maybe some SS brake lines.Back to the issue of picking up the inside rear tire. I see two issues.
#1 Center of Gravity
#2 damping/spring rate
Possible solutions
Buy Ohlin's DFV's
might have to break out the CC for this one!OR
Buy a 14-15k Hyperco spring and test 12k front 15k rear
play with the rear bar
If I can get the spring rate to resist roll...i can run less static camber and have a better contact patch under braking! win win!
AND
Work on reducing front weight
strut tower bar -> Carbing?
Lower/move mini battery
Move ACD pump to rear of car
Remove AC
lighten subframe braces and fasteners
lighten engine mounts
light weight o2 housing
light weight manifold
lower the seat and driver
lighten the subframe brace (like Buschur's setup)
Mostly focusing on removing weight from the front of the car...and removing/moving weight from high points to lower points.
If I can drop 100 pounds off the front end of the car... my front tires will love me.
Things to buy
TRE rear diff ~450 shipped
Girodisc 2pc Fronts ~ 750
Girodisc brake lines ~ 100?
Hyperco springs ~ 140
FP Green ~ 250 (forgot to mention this haha)
Total 1690.00 before lightweight parts or possibly Ohlins lol.
Alignment 60
Racegas 50
Pump gas 40
Registration 85
Dyno time 90
Another 325 for setup... I'll be spending ~2015.00 before the next race. :/ I guess its time to get into the garage and start Fabricating some dope parts lol.
Like I told John Mueller after he told me that I just needed "buck up to play with the big boys" I explained it wasn't in the budget. I want to race for the rest of the year... not just do well at one event and then pay off my Ohlins over the course of the winter lol.
Hopefully the car performs appreciably better next time out and doesn't consume parts or require a bunch of changes. Then we might be looking at buying some killer shocks for the final Event in September.
BTW! got some minty Fresh R6's on the way so I'll be selling my current set of 285/30/18's!
Question for anyone reading this... HOW DO YOU SUGGEST I GET THE INSIDE REAR TIRE ON THE GROUND (besides removing the rear bar and going to 8k springs in the rear)
Jul 17, 2010, 09:06 PM
#117
TRE rear diff upgrade coming first thing monday. I'm going to do the exchange. I can't friggin wait! We were doing inside rear tire burnouts on the track. You can hear it on the in car video.
Scott O'Farrell driving (roommate)
http://www.vimeo.com/13417056
ACD relocation has been planned. I'll be using a custom hydraulic line and replacing the evap canister with the ACD pump. Waterjetting some brackets and making it happen. I WILL off the ACD relocation kit for sale. I think that is a LOT of weight in the wrong place.
Scott O'Farrell driving (roommate)
http://www.vimeo.com/13417056
ACD relocation has been planned. I'll be using a custom hydraulic line and replacing the evap canister with the ACD pump. Waterjetting some brackets and making it happen. I WILL off the ACD relocation kit for sale. I think that is a LOT of weight in the wrong place.
Jul 18, 2010, 10:52 AM
#118
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Another issue that peaked its head during the first heat...the brakes got soft. Not like boiled fluid...just soft... all the time. We both scratched our heads knowing that we had freshly bled RBF600 in the car...WITH the Ti shims. We both said... well we're not boiling the fluid and the brakes are always there. We'll inspect later. I inspected in better lighting. The slotted rotors I once had are no more. I think we're past the minimum wear on these things.
Solution? 2 piece Girodisc front rotors And maybe some SS brake lines.
...
Another issue that peaked its head during the first heat...the brakes got soft. Not like boiled fluid...just soft... all the time. We both scratched our heads knowing that we had freshly bled RBF600 in the car...WITH the Ti shims. We both said... well we're not boiling the fluid and the brakes are always there. We'll inspect later.
I inspected in better lighting. The slotted rotors I once had are no more. I think we're past the minimum wear on these things. Solution? 2 piece Girodisc front rotors
And maybe some SS brake lines....
l8r)
Jul 18, 2010, 11:05 AM
#119
Replies within!
I have to admit I'm a little confused. Didn't the car always behave like this? Nope... we couldn't get the car to oversteer last outing. PERIOD. While trailbrake induced rotation is better with my current setup, it was there even with the stock setup. Ditto for the lift throttle behavior.
Your brakes being soft all the time is probably due to knockback. This issue raised its ugly head the first time I tracked my Evo on R-comps.
Did you replace your wheel bearings? Did you upgrade them? Any recommendations? thanks Ludikraut!
l8r)
Your brakes being soft all the time is probably due to knockback. This issue raised its ugly head the first time I tracked my Evo on R-comps.
Did you replace your wheel bearings? Did you upgrade them? Any recommendations? thanks Ludikraut!
l8r)
Jul 18, 2010, 07:23 PM
#120
i measured the rotor thickness...
RF 31.xx mm
LF 30.7x mm
still more than the minimum of 29.8mm
I measured my old rotors that I bought the car with LOL 26.8mm!!! I had to take an angle grinder to the lip on the outside to get my digital calipers to read it lol.
RF 31.xx mm
LF 30.7x mm
still more than the minimum of 29.8mm
I measured my old rotors that I bought the car with LOL 26.8mm!!! I had to take an angle grinder to the lip on the outside to get my digital calipers to read it lol.