bpracer said:
The only thing I can think of is that the full-droop length may be affected (shorter) than with the non-R springs so it has to find the new limits for the ride height sensors. Range difference.
Maybe.
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R-springs on GT350
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The only thing I can think of is that the full-droop length may be affected (shorter) than with the non-R springs so it has to find the new limits for the ride height sensors. Range difference.
Maybe.
The car seems perfectly normal. I really can't tell a great deal of difference. It seems slightly stiffer.
I can see the relearning if you replace a shock or the travel sensor, that would be like re-calibrating the electrical signal so it knows what full droop is from the sensor. You have to do a similar thing on my Ducati's throttle positioning sensor if you change ECUs.
I'm guessing if you put slightly stiffer springs and lighter wheels on a track pack, the difference to the MagnaRide may be a wash. The stiffer spring will try to overpower the shock more, but lighter wheels will be easier to control.
Put them on your car and we will have two data points. Believe me, I thought these would lower the car a little like 1/4"-1/2".
I can see the relearning if you replace a shock or the travel sensor, that would be like re-calibrating the electrical signal so it knows what full droop is from the sensor. You have to do a similar thing on my Ducati's throttle positioning sensor if you change ECUs.
I'm guessing if you put slightly stiffer springs and lighter wheels on a track pack, the difference to the MagnaRide may be a wash. The stiffer spring will try to overpower the shock more, but lighter wheels will be easier to control.
Put them on your car and we will have two data points. Believe me, I thought these would lower the car a little like 1/4"-1/2".
The R I measured at the Laguna Historic races last year was 1" lower than the Track Pack sitting next to it. Both were preproduction cars. @Moto and I have measured our production cars and there is only 1/2" difference between the two. Either the R got raised or the TP lowered 1/2" before going into production. So the only appreciable difference in ride height is the tire height.
Now that I have my vorshlag camber plates and cortex front and rear lower control arm bearings I'll be installing everything as soon as my work load slows down.
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Droop would be effected by strut or shock length not spring length. Reading the service manual states a relearn was needed when the suspension was replaced or serviced. I'll have to read it again.ArizonaBOSS said:
I completely understand the relearn issue. I'm a mechanic, just as replacing a crank sensor, throttle body, etc. But I figured the R springs were going to lower the car 1/2" and the tires another 1/2". If the R springs don't drop it I'm gonna be kinda disappointed because I have 305/30ZR19 tires and I hope the tire to wheel well opening isn't larger. Time will tell.bpracer said:
My thinking was if the springs drop the car 1/4, 1/2" a relearn would be needed because the magride doesn't know "home" anymore over the stock non R springs.
Sorry for the lame pic. I have no idea how to post it
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bpracer said:
How many have installed the R springs and how are your resorts on track ?
93cobra said:
Well crap, I ordered the wrong one perhaps...
I'll have my parts guy double check my work next time. Anyway, I was thinking of fabricating an adjustable bar out of one of the bars I have. If I got the wrong one, I'll get the proper R model one and try it in a couple weeks.
I have run the car at the track (with perhaps the wrong rear sway bar...) If so, that would probably explain the impression that it didn't change much over stock as far as over/under steer balance. It seemed to me it still had a slight understeer. Of course the front stiffness went up more than the rear with the R springs. This was probably offset by the fact this was also the first time I ran the car with camber plates.
I'll have two more opportunities to run the car in November. The second track will be a much smoother with turns more conducive to determining what is really going on than what I've run on so far. Sorry I can't be more helpful right now.
Flyboygsxr
ADAM
I didn't really notice any significant amount of understeer in the car on track. The Boss in stock form was a lot worse in the understeer department. A little trail braking to get the car pointed in the right direction and to set the front and it goes where you want. The only time understeer reared it's ugly face was when I went too hot into corner. The only thing I see doing to my GT350 is eventually finding some lighter wheels, maybe an aluminum driveshaft, and a slightly more aggressive brake pad. I was really impressed with the stock pads but after a day on track the bite did start to fade away though the brakes never waived. The stock GT350 pads lasted me three days on track before I swapped them. I picked up a new set of the front OEM pads for $240. Not sure what the going price is for the pads but they weren't easy to find. The rotors still haven't started any spider cracking after 4 track days. The Boss rotors would be spider cracked after one day on track with race pads but the 350 did the job on the OEM pads. Super impressed with the car, I just wish it was a little lighter.
I've been on track with the GT350 six times now including the one day at GT350 TA. I didn't experienced any serious understeer in the two days on the stock tires and setup but with my 305 square rotatable setup of PSC2's the car is very neutral. While I'm not ruling out changing the springs I'm now more inclined to leave my car stock. The change of springs would be to lower the car mostly for looks and to reduce brake dive a touch. My non R with lighter wheels/tires (10 lbs per corner) and PSC2's is hooked up on track and I need to learn to get on the gas sooner at apex.
OK, I was really confused when I first picked up the FR3Z-5A772-E bar and compared it to my stock Track Pack rear bar.
The length of the "arms" is exactly the same, or at least not discernible to me. Then I thought I saw a difference...
The diameter is bigger! Not what the specs say but the R "-E" bar is .94" in diameter, and my stock GT350 TP is .875" in diameter (.875" = 22.2mm as in specs below)
I can't really tell if the wall thickness is different, I can only measure the thickness of the smushed end and that's not very accurate. But probably the same wall thickness tubing.
My parts guy will check for different bushings on Monday.
I guess they made a running change from what is printed in the GT350 supplementary owners manual:
Rear stabilizer bar
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in)
GT350R
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in )
with 8mm (0.31 in) shorter arms than
GT350
The length of the "arms" is exactly the same, or at least not discernible to me. Then I thought I saw a difference...
The diameter is bigger! Not what the specs say but the R "-E" bar is .94" in diameter, and my stock GT350 TP is .875" in diameter (.875" = 22.2mm as in specs below)
I can't really tell if the wall thickness is different, I can only measure the thickness of the smushed end and that's not very accurate. But probably the same wall thickness tubing.
My parts guy will check for different bushings on Monday.
I guess they made a running change from what is printed in the GT350 supplementary owners manual:
Rear stabilizer bar
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in)
GT350R
22.2mm DIA x 3.9mm wall (0.87 x 0.15 in )
with 8mm (0.31 in) shorter arms than
GT350
Mark, your last track day was with the R springs and sway bars? While I'm sure it's stiffer do you think it's faster?
Well, I did the unforgivable sin of changing multiple things at once, camber plates, alignment and R springs. The rear bar was not the R bar as I guess I had ordered the wrong part. The car needed more rear roll stiffness.VoodooBOSS said:
As the R front springs are 10% stiffer and the new rear bar is 10% stiffer, the new rear bar should help offset the understeer I felt. I'm sure it will feel faster.
Nov 21, I'll be at a smoother and faster track
The springs are not a big change, they probably only offset the increased roll that stickier R tires create.
I'm still not pushing the car too far. I drove harder in the Track Attack school cars in Utah. Even then, I felt much more at home in the Boss 302 track cars the next day.
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Finally got to the track today (MSR-Cresson) with the larger rear sway bar to match the R springs and it does the work better as one would expect!
It was chilly in the morning and I wasn't trying to push the car too much, I really went to coach a friend that just picked up 2001 911 Turbo... But then there was another GT-350 there and it left me while my tires slid around.
The last session I ran I finally got the air pressure low enough to get the tires to stick. Overall the car felt neutral, with some lower speed understeer (but likely I was getting in on the gas to soon). The car had more oversteer on fast turns until the tires got hot. At that point the car seemed more neutral overall.
I must have been spinning the left rear more than I thought because it was 2psi higher than the rest when I finished.
My tire pressure gauge shows about one psi less on average than TPMS readings.
My next tire pressure starting point for this track will likely be:
LF 27.5 RF 27
LR 28 RR 26.5
I guess I need to take some tire temps.
The other things that was absent this time was some shuddering from the front end when pushed really hard. My only other modification was a Steeda G-Track brace. It seems to help tram-lining on the highway as somebody in the M6G forum stated that it "cured" that problem for them. I think it is slightly better, but certainly far from cured. It's pretty cheap, looks like it should do something to triangulate the front sub-frame and it can't hurt other than adding a little weight.
I'm getting more comfortable with the car but a little voice in the back of my head keeps telling me I have 50+ payments remaining.
It was chilly in the morning and I wasn't trying to push the car too much, I really went to coach a friend that just picked up 2001 911 Turbo... But then there was another GT-350 there and it left me while my tires slid around.
The last session I ran I finally got the air pressure low enough to get the tires to stick. Overall the car felt neutral, with some lower speed understeer (but likely I was getting in on the gas to soon). The car had more oversteer on fast turns until the tires got hot. At that point the car seemed more neutral overall.
I must have been spinning the left rear more than I thought because it was 2psi higher than the rest when I finished.
My tire pressure gauge shows about one psi less on average than TPMS readings.
My next tire pressure starting point for this track will likely be:
LF 27.5 RF 27
LR 28 RR 26.5
I guess I need to take some tire temps.
The other things that was absent this time was some shuddering from the front end when pushed really hard. My only other modification was a Steeda G-Track brace. It seems to help tram-lining on the highway as somebody in the M6G forum stated that it "cured" that problem for them. I think it is slightly better, but certainly far from cured. It's pretty cheap, looks like it should do something to triangulate the front sub-frame and it can't hurt other than adding a little weight.
I'm getting more comfortable with the car but a little voice in the back of my head keeps telling me I have 50+ payments remaining.
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