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571 rwhp - NEED HELP WITH TIRES

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The only supention mod's I've done to my car to dates is swap my LCA's for the CHE LCA's in hopes of hooking up a little better. It didn't hook up any better, but the wheel hop went away and no more fish tailing and better control. So there was improvement and I got 75% of what I wanted. I think I may need relo brackets but I wait until I put the PSS on in spring stock tires have seen better days. I'm curious to see what your fix will be. I would loose the 20" rims and go back to stock or an 18" like suggested, a deeper sidewall will absorb some of the initial shock when you mat the gas.
 
yankeehick said:
I'll be in the market for some tires this summer. Had the Boss supercharged for a few months now and it's great (putting down 571 rwhp) but I'd like some input on what summer/sticky tires I should be running to get the best possible performance/traction. I can't keep the tires from spinning and I realize this is due to the temperature outside currently. It's been anywhere from 7 degrees to 60 degrees in just a week span. Granted, I don't take the boss out when it's wet or under 30 degrees but my problem (if you should even call it a problem) is I can't seem to put down any traction. This morning, (45 degrees) I was in a more spirited driving mood so I came out of first and second pretty quick (due to tire spin of course) and engaged third with a good amount of throttle (probably half way down). I spun in third like I would have in 1st or 2nd if I kept it down. It was pretty nuts.

I currently have great tread on my toyo proxes 4 but that might be half of the problem right there. They probably aren't the right tires for max grip. The other obvious culprits here: weather temp and colder tires. Since I've never had this much hp before I have some general questions that some of you may be able to answer - especially if you've supercharged/turboed your stangs.

First off, am I just wasting my time by even asking the question?? I want to know if ths topic is pointless to begin with. I don't want to buy wider tires (currently running 295s) just to drop the coin on 305s and still break loose ( within reason ). Now I'm not looking to hook from a dig here or anything... but hoping to be able to hook if I want to go WOT at a 50mph roll.

1) Based on your experience, would there have been a significant difference if the temp outside was 85-90 degrees using same tires?? How much difference really?
2) Aside from racing slicks / drag radials, is anyone with this kind of power able to go through gears more agressively without too much tire spin on street tires? (Again, not from a dig - from a roll on start). If so, what kind of tires are you using or recommend?

Background info on my wheels/tiers: I'm running forgestar F14s on 20" rims back and front. 9.5 front 10.5 in back. Tires are toyo proxes 4.

I can't even imagine what 700 + rwhp would be like on this car. Based on what some other guys are putting down 571 rwhp is tame (just kidding).

If you want to check out my supercharger thread it's here >>>>>>>>>>https://trackmustangsonline.com/index.php?topic=6238.0

Summer tire comparison for grip:
Best (1st place) MPSS
Worst (9th place) Pirelli P Zero. Was this not the factory OEM tire that regular Bosses came with? I forgot as I got it changed at the dealer before leaving the lot.
http://www.caranddriver.com/comparisons/michelin-pilot-super-sport-page-10
 
Grant 302 said:
Well, they can't quite advertise it as a monster RWTQ street tire can they? It's DOT legal and lots of high HP/TQ cars run them on the street.

Fair enough. My main concern with it was the potential for hydroplaning, although the OP said he was not driving in the rain. For me hydroplaning could be an issue but after seeing your post I read reviews and they were very positive for dry and wet street use. I would give it a try but in 19 and 20 inch rims they are available only in 305 and 315 as widest. I do not want to run 18 inch wheels and probably would like to stay with 19. In 19 inch 305 is the widest R888 while people are able to fit in 325 Michelin PSS. It could be of course that a 305 R888 has more grip than a 325 MPSS but this is most likely not the case. However, you are right if someone is running 18-inch wheels and is careful about potential hydroplaning then the R888 looks as a good street tire and available in close to maximum width.
 

Grant 302

basic and well known psychic
NWBoss said:
Fair enough. My main concern with it was the potential for hydroplaning, although the OP said he was not driving in the rain. For me hydroplaning could be an issue but after seeing your post I read reviews and they were very positive for dry and wet street use. I would give it a try but in 19 and 20 inch rims they are available only in 305 and 315 as widest. I do not want to run 18 inch wheels and probably would like to stay with 19. In 19 inch 305 is the widest R888 while people are able to fit in 325 Michelin PSS. It could be of course that a 305 R888 has more grip than a 325 MPSS but this is most likely not the case. However, you are right if someone is running 18-inch wheels and is careful about potential hydroplaning then the R888 looks as a good street tire and available in close to maximum width.

I don't know for sure, but I'm under the impression that the 305 R888 would be grippier than the 325 PSS.

For the OP, it looks like there are better options for his 20x10.5 rears in R888. 315/30-20 vs. 305/30-20 in the PSS.
 
Grant 302 said:
I don't know for sure, but I'm under the impression that the 305 R888 would be grippier than the 325 PSS.

For the OP, it looks like there are better options for his 20x10.5 rears in R888. 315/30-20 vs. 305/30-20 in the PSS.

Interesting. Is there a way to find out for sure with hard data? I am not trying to be difficult. I am in the process to select wheels and tires for upgrade in the next few weeks and I want to install the widest rim and tires with most grip possible on each end. It would be great to have some hard data for grip level other than the usual "Joe believes, based on his 800-mile experience with the tire, that it is really great" or similar reviews on tire sites.
 

Grant 302

basic and well known psychic
NWBoss said:
Interesting. Is there a way to find out for sure with hard data? I am not trying to be difficult. I am in the process to select wheels and tires for upgrade in the next few weeks and I want to install the widest rim and tires with most grip possible on each end. It would be great to have some hard data for grip level other than the usual "Joe believes, based on his 800-mile experience with the tire, that it is really great" or similar reviews on tire sites.

I don't know of anybody who has used the two back to back, so I can't comment on any hard data. I have a set of the PSS with 295 rears. Great all around, but not as much forward grip as my 275 R-s3 Hankooks in the dry. I've gotten lots of 1st hand comments on the R888 as relates to high HP and TQ cars...and a little from other track rats. And I'm under the impression for forward dry grip only, that the R888>R-s3>PSS in similar sizing.

But don't get me wrong...PSS are amazing all-around tires that wear really well. Exceptional in the wet and cold too.

And I hear you about tire reviews...it's hard to get real info from reviews from guys who just made their purchase and are happy with their new tires, which are just better than their old crappy tires. It's useless data.

What are you using the car for and what's your setup? Might help others point to a tire that will work for you.
 
Grant 302 said:
... And I'm under the impression for forward dry grip only, that the R888>R-s3>PSS in similar sizing.

But don't get me wrong...PSS are amazing all-around tires that wear really well. Exceptional in the wet and cold too.

....

What are you using the car for and what's your setup? Might help others point to a tire that will work for you.
Grant: I do not want to hijack the OP's thread but because you asked my circumstances: I use the car on street only and cross country driving and it is my DD. Because of the wet performance (I have 9 months of wet roads) I plan to go with MPSS. Currently I am NA but considering SC on low boost only (~500-530 RWHP maximum) to avoid most of the traction and heat soak issues I hear on these boards while having a little more acceleration. A little more HP but not much more.

OP: Again, I did not want to hijack your thread but I am in a very similar situation as you looking for the maximum grip. What I found very informative was to read the Vorshlag blog about their quest for more grip. http://www.vorshlag.com/forums/showthread.php?p=57671#post57671
Message #225 and some others (you will need to page through their blog). That blog and other reports inspired me to take care the tranny, suspension and tires first before even thinking of SC. We are at the last steps (wheels). We did all and more what was suggested to you in the earlier posts.

I plan to use a 12 inch rear wheel and 325 tires. I am just hunting down the offset that would work with it. The best example I found so far is 61 mm for a guy running 20x12 and 315 R888. On the photos his setup looks completely flush but I do not know if he has any rubbing issues and his supporting mods. If you read the Vorshlag blog you will see that for 12-inch and even some 11-inch setups you will need Watts link, bump stop bracket removal and some more mods. Message #15 is a good summary from one of the Vorshlag guys:
https://trackmustangsonline.com/index.php?topic=1774.0

If you decide on 18-ich rims then you can order from Vorshlag. Otherwise they do not publish the offsets.
 
OP: Again, I did not want to hijack your thread but I am in a very similar situation as you looking for the maximum grip.

It's OK. I'm learning a lot. Thanks for the thread. It's got a lot of good info.
 
yankeehick said:
OP: Again, I did not want to hijack your thread but I am in a very similar situation as you looking for the maximum grip.

It's OK. I'm learning a lot. Thanks for the thread. It's got a lot of good info.

Glad it helped. As for the grip, maybe we both are chasing dreams here. On the Vorshlag blog there is a picture where they show that they could spin the rear wheels during autocrossing. The car had around 420-430 RWHP and the tire was the 345/30/18 Hoosier! So, I am not sure if it is realistic to find anything that will not spin at 571 RWHP. Plus their 345 setup is not even possible without flare because it rubbed everywhere.
 
NWBoss said:
Glad it helped. As for the grip, maybe we both are chasing dreams here. On the Vorshlag blog there is a picture where they show that they could spin the rear wheels during autocrossing. The car had around 420-430 RWHP and the tire was the 345/30/18 Hoosier! So, I am not sure if it is realistic to find anything that will not spin at 571 RWHP. Plus their 345 setup is not even possible without flare because it rubbed everywhere.

Yes, but that car was restricted by the SCCA rule set. It did not have any rear geometry correction and was lowered too much. By not lowering it much and using a rear lower relocation brackets and getting rid of the soft bushings in the rear it should -help- with the hookup even if it doesn't cure it.

Next would be a set of dampers that were the right length and tuned for the rest of your suspension. And as it was already mentioned, a 20" tire is going to hurt your performance compared to an 18".
 
modernbeat said:
Yes, but that car was restricted by the SCCA rule set. It did not have any rear geometry correction and was lowered too much. By not lowering it much and using a rear lower relocation brackets and getting rid of the soft bushings in the rear it should -help- with the hookup even if it doesn't cure it.

Next would be a set of dampers that were the right length and tuned for the rest of your suspension. And as it was already mentioned, a 20" tire is going to hurt your performance compared to an 18".

I did not know that geometry was not corrected at that time. Later you had the Watts link on the car and other mods. As for 18" tires. My problem with 18" tires is that the street summer max performance tire selection is limited. For example, Michelin stopped making PSS for 18" wheels in the 305 and up sizes.
 
This looks like a new book with relevant info:
http://www.amazon.com/The-Racing-High-Performance-Tire-Balance/dp/0768012414
Edit: I meant good book. It is new only for me.
 
NWBoss said:
This looks like a new book with relevant info:
http://www.amazon.com/The-Racing-High-Performance-Tire-Balance/dp/0768012414

That book has been out for some time. I've bought two copies. The first was destroyed during a motorcycle trip to Speedweek at the Bonneville salt flats and the other is loaned out to Terry Fair. Have to get him to learn something! ;D

It's one of my recommended readings for people trying to understand the concepts behind suspension dynamics.
 
NWBoss said:
I did not know that geometry was not corrected at that time. Later you had the Watts link on the car and other mods. As for 18" tires. My problem with 18" tires is that the street summer max performance tire selection is limited. For example, Michelin stopped making PSS for 18" wheels in the 305 and up sizes.

I don't think the Michelins are the end-all-be-all for performance tires. They do well in daily driving conditions (rain and cold) but they aren't the stickiest. For that go to the BFG Rival in a 315.
 

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