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Lack of traction
Just looking for some advise before I make any purchases but I recently went turbo and I ordered 255/40/18 for the rear and there Michelin pilot super sports. However if I go WOT even at 55 the back end just starts spinning what have my fellow power junkies done to help keep there rear end on the ground
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Smooth application of throttle pedal.
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Lol Sent from my iPhone using Tapatalk |
Cant go much wider than that on the stock body, how much power are you making?
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Lightweight car with a lot of power on street tires. Gonna have to be pretty easy with the throttle modulation or go to a street radial.
Wouldn't happen to know how much torque would you? Breaking lose from WOT in the top of the rev range or from 2500? |
Try to get some anti-squat out of the rear suspension, let it squat more under acceleration?
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I'll be able to tell you how much tq tomorrow and around the top end I normally don't like to speed on the street but I've been driving it pretty hard since I just got it back from my shop and if there's anything wrong with it I want to know before I drive back to nc
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300hp + 55 mph + 255/40/18 PSS and "the back end just starts spinning" dose not add up!
Things to look at: tires way over inflated? do you have mad camber so only half your tread is on the ground? 800lbs springs with 1.5 in drop? (IE no squat)? are the roads covered in snow, ice or lots of water? are you dropping the clutch at max TQ to try and spin the tires? |
something isn't right, you should have no issue hooking up at that speed and power.
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Only a very very slight camber till I can roll the fenders and adjust everything
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I'll look into this and see if it helps thanks guys Sent from my iPhone using Tapatalk |
Another thing to check is air/pavement temperatures... if the tires are too cold they won't stick well at all.
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^this…it's why I bought a winter beater. summer car with similar #s. At 334whp I was putting 261tq (90 degrees ambient) Summer tires not so nice in winter temps.
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Trade your turbo for my CAI and you will solve the problem easily. my loss your gain. . |
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300rwhp at 55mph (80.7 ft/s) gives 2045 lb. of thrust at the rear tire contact patches. 300hp * 550 ft-lb/s/hp /80.7 ft/s = 2045 lb. If all that made it to the ground, ~0.7g acceleration (2045/2950 = 0.7). At that acceleration, weight transfer is ~12% (0.7*18" c.g. height/101" wheelbase =.12) , load distribution ~42F/58R, load on rear tires ~1714 lb. Effective coefficient of friction at the tire/ground interface would have to be 2045/1714 = 1.19 to put that down. It's not surprising that even very good tires are overwhelmed. |
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Batman did you do tht in your head or did Alfred lol Sent from my iPhone using Tapatalk |
Throw a few sandbags in the trunk ;)
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I might actually do tht Sent from my iPhone using Tapatalk |
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To actually calculate how much power is making it to the tires you need to know what gear it was in and how much power it makes at that RPM. Knowing peak hp means nothing if it peaks at 6500rpm and he was driving at 3500rpm. I think most people were assuming he wasn't driving around at 55mph in 2nd gear, but probably 5th or 6th which would put it low in the rev range and nowhere near 300whp. |
Surely no one is assuming he's getting wheelspin at 55mph in 5th or 6th gear! If he's making 300rwhp at 55mph, most likely he has to be in 2nd gear. To make that much power at that speed in 5th gear would require about 570 lb-ft of torque.
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Stickier tires can also cure traction issues, as well as suspension tuning for softer rear rates that allow the car to squat a bit more for drag racing use...
Tires do make a HUGE difference and while going wider will allow for some increase by making the contact patch larger, it also has to maintain correct contact patch temperature, and bigger tires on a light car also has inherent issue of taking much longer to heat up. Going to a more aggressive tire compound will make a much more drastic difference...than small difference in size in the case of traction, cornering and braking. |
I'm betting temperature has something to do with it. Pss are summer tires, don't do well in cooler conditions
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Agree, temp is probably a big factor. PSS are great tires, but at ambient temps below about 50F, they don't have a lot of grip on the street, don't get near optimal operating temp.
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This is true i have the same tire in a michilen super sport 245/40-17 65mph punch in 3rd gear car gets side ways forget about first and 2nd under boost. and once (no one is gonna believe it).....but on a chilly afternoon with the sun out on the salt covered highway that was BONE DRY after I ran a V8 challenger, got completely sideways in 3rd and when i hit full boost in 4th the tires loss traction at 90mph. i was at 375whp and 262 trq |
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OP, what gear are you when this is happening? |
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@ZDan, you're up :D
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Must be a temperature issue? Driving on a dirt road or snow, maybe? Don't see how you should be spinning 255/40-18 Pilot Super Sports (btw, those are an inch bigger in diameter than stock, intentional?) at less than 4000rpm with a 2.0 turbo that maxes 300hp. |
OK, at indicated 55mph you're only making 150rwhp. Something else is going on here...
No way you should be spinning the tires in 4th gear at that speed! |
To be honest I haven't been having much problems with it in the last 2 days I think maybe the roads could've been a little damp
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I've never spun 4th on the stock tires with 360whp wtf are you doing dumping the clutch? I do spin third but I can feather it so it hooks.
Sent from, The Frozen North |
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happy medium, giant bags of kitty litter? |
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The car is in Miami we only have summer :-| Sent from my iPhone using Tapatalk |
Could your new tyres be old stock ?
If they have been sitting around in storage a couple of years traction can be way down on fresh "new" tyres |
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