Hey guys / gals

Recently put on the Whipple supercharger and Whipple Crusher TB - now my next problem - what tire do you recommend to get the power to the pavement? I would like to stay with the 8.5 factory rim - really like the look. Also, if you recommend a wider rim - to accommodate a 305 tire - will the extra width really help considering the extra cost of new rims considering a 275 size of the exact same 305 tire/ softness level?

 

When do you plan on driving this car? The Nitto drags are fantastic for occasional driving. Stiff sidewall to handle the turns but stick well. They last about 8k miles and don't do well if the road is wet at all. The MT drag radials have a softer sidewall but stick even better so less on the curves but better on straight. Toyo R888 is a road race tire that is great on turns and does a little better in wet but is not a drag race tire so they do spin some. All season or summer radial will not stick as well as the race tires but you can drive them every day.

 

You are never going to get 777HP to hook on anything that you can fit on a 8.5" wheel. Heck, nothing short of a DR will even hook on the street at those power levels. You are going to have to go big and wide and as sticky as you can get in order to make all of this power hook and even then good luck.

When it comes to selecting tire size, the number that people pay attention to the most is the one that they shouldn't be paying so much attention to. Granted it is nice to say that I have a 315 size tire on the back because it sounds like you have a monstrous tire in the rear and all of this rubber to put down on the road. That isn't the case at all! The thing you should be paying THE MOST attention to is the tires tread width and thank goodness for Tire Rack because they actually measure this statistic! This is actually how much rubber you are going to put down on the road so pay careful attention to this.

Now you are also going to have people saying that you can fit such and such a tire a 8.5" wheel and it will give you a nice wide tire. While you can do that it you can fit a certain tire on a certain wheel width, I choose not to do this. I prefer to make sure the tire's measured rim width is within the spec for the wheels that I have for optimal performance of the tires. After all I didn't just spend $3-400 on a tire for it to not be performing at its peak. When a tire is stretched you will have increased turn in response due to the reduced sidewall flex, but you will have decreased break away characteristics, and it will ride very poorly (if the tire is over stretched). Same goes for a bulging sidewall, you will have decreased handling characteristics, vaguer steering feel as the sidewalls are flexing greatly, and the carcass of the tire will deform and create uneven pressure along the surface of the tire.

Also, do your homework on a specific tire as this is THE most important part of your car. All of your handling, ride characteristics, power delivery etc. all rests on these 2 or 3 inch patches of rubber that are touching the road. Take the Michelin Pilot Super Sport wheels which are regarded, almost unanimously - except Patrick - as the best tire on the market today, - very good hydroplaning resistance, superb lateral grip, and amazing ride quality - but when you look at their straight line grip on guys with high HP cars, it just isn't all there. Now if all the above is more important to you than 100% straight line grip then it may be a great option for you. This is Brian's (skwerl) Bullitt that was making north of 800HP after choosing the wrong tires. He said that they started to turn into hockey pucks on him and well ....





Not exactly the short and sweet answer you were looking for probably, but these are important items to not skimp out on IMO. I'm not saying you have to go spend 3k on tires or whatever as the best tire is the best performing tire for your needs and on your budget plain and simple.

 

Nicely stated Sean!

 

Brian's car was at about 640 rwhp, and that happened.
With close to 800, you really need to build suspension and get the right tire, and even then you can't just flat-foot it everywhere, you need to use that right pedal cautiously

 

Maybe I am thinking of Bruce then. I could have sworn he was around 800 on that build.

 

My 295 Michelin Pilot super sports on my 14 gt500 with 700 rwhp and I get traction at about 60 mph in 3rd gear. Pretty ridiculous actually

If you like the stock wheels why not have them widened? People knock the practice but if you do some research you won't find any failures of these wheels. They make a 5/8" wheel spacer that get you a little more tire under the back too and 5/8" isn't really detectable by just looking at it.

 

Sorry guys let me clarify. Not a track car. Just a dd. Maybe drag strip 1x yr

 

I'll be first to ask: "then why the blower and why pushed all the way to 777 rwhp?"

A dd does the "dd" duty just fine with 435 crank-hp, the factory un-boosted rating for the 5.0, and if you "must" have it boosted, there's certainly lower power levels that won't require so many other changes to the car and so much driving skill, to actually stay on the road, shiny side up.

 

Seriously, you ask why so much horsepower? 😂😂😂. Because I can.

 

My car is almost exclusively driven on the street, because of traction issues I wasn't successful at the track and gave up trying.

I did learn something racing my car last year. It doesn't necessarily matter how much HP you have, it's how much you can get to the ground. With my car I'm able to put around 450 RWHP to the ground despite having close to 700 RWHP on a dyno. I figured this out because other mustangs running slicks with 400-450 RWHP, that didn't have any traction issues, were running the same 1/4 mile time as me at my local track.

I talked with a guy running .5 seconds quicker than me in a 2014 gt500 and asked what his secret was. He actually had less mods than me, made 50 RWHP less but he had a setup rear end and nitto tires. That really got me thinking about the correlation between HP, traction, and speed.

 

So nitto tires. The 555?'s

 

That's your best chance with stock rims IMO. A friend of mine has a 2013 gt500 and only runs nitto 555s, he told me it was a mistake to go with the the michelins if I was looking for traction. I got the michelins anyways because I really like the way they looked, they were safer in the rain, and I didn't expect that I would not be able to get traction until 3rd gear. I think they are the best tire besides the nittos.

If you get a tire that's too wide for your rim it will bulge to the center and actually give you less of a flat contact patch than a properly fitting tire.

 

*le sigh*

 

Throw some Sumitomos on there and call it a day.

 

Thank you Ecostang. Your post was helpful

 

Seriously, we ask (jumping in on this) because that kind of streetable horsepower is *insane* and frankly doesn't belong on the streets.

Yes it's hella cool. But yes, it's hella dangerous. And not just to you.

Therefore, we ask. It is a responsible thing to do.

That said, if you can handle that car when it tries to go sideways (and even the pros can't always do this, mind) then go for it.

I personally think it's silly enough we have 400 and 500 horsepower pony cars running about, much less that much and the torque associated with it.

It's not just your life regarding that car at that point, I think. Think wisely.

Then do it anyway, because like you say... we hadda ask?

 

HA HAAAAAAA
I had those on my '05 Ram Daytona 4X4 regular cab.


HTR Sport H/P

 

Absolutely!


But you ain't gonna make it on a 8.5" wheel. Unless it's a 15X8.5 with full slicks or ET streets. In fact there is absolutely no logical reason to not upgrade the wheel size.

 

I would agree with you with some clarification, the clarification I want to offer may help someone finding themselves with a 700+ hp for the first time No one wants to wreck their car, injure themselves, or injure someone else. 777 HP can certainly be dangerous if not respected.

OP if this is your first time with a car this powerful I'd like to offer a few suggestions that I learned while getting accustomed to my modified Shelby, you may already know these things and if so then maybe it will help someone else.

1. Traction is king, with traction the odds of you accidentally putting the car in to an unwanted slide is minimal. With 8.5" rims you don't have a chance, I'm just being honest. If you want to keep the same rims add a spacer and widen them to 10".....even with a 305 tire your asking a lot.

2. Temperature is a big factor in traction. The the colder temps, the colder the road, the harder your tire gets. When I'm driving my Shelby I always pay attention to the temps when I want to play around. Below 60f you are asking for trouble, anything above 75f I'm usually hooking up a lot better.

3. Heat your tires up by spinning them some at low speed, when it's safer, before you do any high speed pulls. Some quick second gear burnouts are fun and it makes the tire stickier and safer for high speeds.

4. Leave the traction control on especially when driving at higher speeds, If I downshift at 70 mph and floor it with trac ON I still fishtail some. The only time I turn off the trac control is if I'm racing or trying to burn the tires off at slower speeds.

5. Learn how to handle your car constantly getting out of shape! It took me at least 5k miles before I felt comfortable driving the car at full power. I'm comfortable now with turning trac off and fishtailing from a stoplight up to 60-70 mph and I don't feel like I'm risking passengers or other people on the street. It's not to be taken lightly, things happen incredibly fast with that kind of power.

I'm an experienced driver with 2 decades of driving hard, but I almost lost my Shelby to an unexpected slide when it was new. I left my house and turned off trac control and forgot about it. I went to pass a car going 50-60 mph on a single lane road near my house. I downshifted, gave it some gas, and swung out to go around the car. My car lost traction and I ended up passing the car sideways as I went around it. It probably looked awesome, like I meant to do it, but I nearly S*** my pants over it.

I know you didn't ask, so please don't take it the wrong way that I'm offering this advice. It's not intended to be disrespectful of your driving skills, again you may already be aware of the things I've mentioned.