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This track is a flat, no bank track. Some of the turns have depressions (more for drainage than anything). Track was wet/damp during these runs as it was raining earlier.
Thoughts:
The RC-F is a track car through and through. It kept the heat on most of the competition. '17 Z06 could only make time (about 1/2 second) on the straights and lost it everywhere else. Mustang 5.0 on 4 track slicks couldn't get away at all. That said, it's got some definite shortcomings and I see why people spend $6k+ on suspension parts-
Understeer is the understatement of the year. Torsen gives me extreme understeer, to the point that the only way I'm turning at speed is making stability control run brakes to pull me around. Turning off stability control actually made cornering impossible, the back end wouldn't break loose and the front end just goes whatever direction it's already pointed.
Hellooooo body roll. I'm rolling for everyone else who isn't.
Stability control? Yeah, I'm pretty sure I really wanted to turn more to the left, not be "assisted" into the grass on the right. This is also a factor of understeer (at random?).
Going too slow makes the engine oil too hot. I've actually never seen it move over to the right side of the gauge before. Flogging the car around the track is a-ok though.
you can fix understeer by running square set up front and rear.
Makes a huge difference in the way the car behaves.
Different tires will be a key too. Oe Michelin’s side walls not that great.
Try a track oriented tire. Finding right fitment is the challenge if you do run square.
Plus if it’s your first time, everyone plows.
Try reducing corner entry speed, turn in with car at the widest point, etc.
It will get better.
Glad to hear you getting out there!
Are you on stock tires? I have written before how their sidewalls are non-reinforced and they tend to flex a lot under heavy cornering load. You will have to pick up 'XL' rated (extra load) rated MPSS or MPS4S tires. They have great sidewall rigidity and have much sharper steering response. I agree with Mingofish the cheapest way to fix understeer is to put sticky tires on. You can buy Michelin Pilot Cup 2 tires and the front will stick a lot better with those.
Also, TVD almost eliminates understeer as long as you don't lift off the throttle through the turn and keep feeding in the power through the turn as it will rotate the rear for net neutral behavior.
OK that explains it. Your staggered ratio is way too big front to back. You added so much grip on the rear by increasing the contact patch to 305 mm (on the stock 10.5 inch rear wheels) while the front is still 255 mm. It will make the front end lose grip a lot faster as you carry higher speeds since you have so much grip on the rear. If you increase the contact patch on the rear, you should increase it proportionately to the front as well. I would personally do 275/295 max to keep the balance. I think the 305 width is not optimal for 10.5.
The stock rear RCF rear wheel is 10.0" not 10½". Fronts are 9.0".
305/30/19 is not recommended on a 10" wheel.
Lou
Yeah, the tire will not be supported properly across the cross section of the wheel width and sidewall will bulge out from the side of the wheel. Hence the excessive roll as OP stated.
Op,
Give the Yokohama AD08R a try. Imo a great compromise between streetable in rain, grip, & tread life.
Its gonna ride rougher though. The side wall way stiffer than oe PSS.
They were the first track tire I used. I used 275/35 square front & back on my oe wheels. You’ll be amazed how much different the car will feel.
Just a disclaimer, 275/35 is a bit larger than the oe diameter.
Car may scrub a tad on high compression, especially on track with a downhill corner. But it’s not a bad scrub if the car isn’t dumped. From your pic, doesn’t look like you’re lowered too much or at all so you should be ok.
I know 275 rears doesn’t sound manly but you’ll be faster and have more fun!
275/30/19 is actually imo the perfect front tire size and don’t scrub. But there’s not a single track tire out there in that size.
All are 35 series or higher...
I ran the AD08R on my TT 350Z in the 275/35/19 and loved them.
Originally Posted by Mingofish
Op,
Give the Yokohama AD08R a try. Imo a great compromise between streetable in rain, grip, & tread life.
Its gonna ride rougher though. The side wall way stiffer than oe PSS.
They were the first track tire I used. I used 275/35 square front & back on my oe wheels. You’ll be amazed how much different the car will feel.
Just a disclaimer, 275/35 is a bit larger than the oe diameter.
Car may scrub a tad on high compression, especially on track with a downhill corner. But it’s not a bad scrub if the car isn’t dumped. From your pic, doesn’t look like you’re lowered too much or at all so you should be ok.
I know 275 rears doesn’t sound manly but you’ll be faster and have more fun!
275/30/19 is actually imo the perfect front tire size and don’t scrub. But there’s not a single track tire out there in that size.
All are 35 series or higher...
11-07-18, 12:24 AM
Finally got to track my RC
