FI and wheel size.
 

Ok so I'm about to go vortech SC, e85/flexfuel, and I've been eyeing up to wheel sizes and I need to know from people who are FI, turbo or sc, which they feel is necessary 17x8 or 17x9

I'll be going with the wedsports tcn105s and what I wanted was 17x8.5, but that isn't an option, so really just want some feedback. Are 17x8's gonna cover it or should I go 17x9's?

@robispec @2forme @sportsguy86 @Pete @kingtut

You want more contact patch. More contact patch requires more section width. More section width necessitates a wider wheel once you're at a certain section width.

@TyperRspec789's car on 225/45/17 was scary with 312hp.

Well yes, hence the thread, and I think the proper term is foot print. I wasn't planing on running the stockers, I don't like to strech tires so 8 would put me around 235, where 9 245/255. Foot print increases with diameter of rim as well but I want to stay 17"

http://www.ft86club.com/forums/showthread.php?t=31920

Changing diameter to 17" doesn't mean this thread doesn't apply to you.

Would you happen to know his torque spike?

No, but his dynos are on this forum. @Pure Automotive Performance has posted them, both gas and E85.

I run a 17x9 wheel with a 245/40/17 tire...Next set of tires will be 255/40/17.

I'll look in to it, I didn't mean to be snippy btw, I'm just flustered that its been 36 hours now to get a basic stg1+ map, and still no response or map.

I know @moto-mike is probably laughing his ass off about it... Well him and @Simmons

I am running 18x8 TC105Ns with Michelin PSS 245/34/18s and it isn't scary. I can sometimes get all the power down in 2nd gear, but then sometimes I will lose traction at partial throttle in 3rd gear depending on road conditions. I don't see any reason to run anything less than a 245 width tires on a forced induction application, and you can fit them on anything from a 8 inch to a 9.5 inch wide wheel typically.

Definitely agree with Tut, would not go smaller than 245 on FI, you need that extra contact patch. Both my car and typerrspec789s car are on 255.

Yeah that thread had nothing of use, he's not FI, and those wheels are ridiculously heavy, not to mention he's running 18x9.5 all the way around on 265's.

robi said he's on 225..

If you are only concerned about performance in a straight line run the 17x8 they will be lighter...for cornering and stability run the 17x9.

K gonna grab a set on 17x9's and run 255/40 on them, thanx for the input.... Now where is @RavSpec

robi's car was a NASA TTD car which means he is limited on what size width and how sticky his tires can be. Many guys in TT competition run smaller width super sticky tires. Heck a Hoosier A6 225 is probably at least as wide as a Michelin PSS 245.

Robi also wasn't FI till recently, I'm thinking now that he has that new found torque he may go with a wider wheel to cope with new wider tires. @robispec

I am going to be running a similar setup to him next week, but I am FI. How heavy are the GramNotLights?

True, there are plenty of tyres that run way wider.
A lot of the guys on 265s aren't actually wider than 245s, some are even only equivalent to 235s.

I've installed and driven a Vortech setup and it is much easier on the tires than turbo. I would imagine the same should apply to the Innovate setup.

25lbs each for 18x8.5

You know I would pay an extra 2k for a car on wedsports then stock wish auto makers start making it an option

I've got 17x9 Weds on my rears with 245/40-17 Yoko S.Drives and a Vortech Stage 1. I'm definitely getting stickier tires next time around, not sure I need to go to 255, but something definitely with more bite than these S.Drives. It can get squirrely even at Stage 1. With E85, you'd definitely throw these suckers loose without much effort.

You may also be looking at 26-30lbs for the tyres.
I can deal with a couple after FI, not extra 10+ lbs per corner though.

we just singed with Weds Sport and will be running there new SA15 18/9.5. We will be testing them with a 275 and hopefully a 285 set up. We will be running a squired setup so the final tire will be the one that fits the front. the SA15 are about 19 lbs.

Stock is 21.5 stock w/tire I belive is 48 lbs, I think tcn105 17x9 with good sticky was 52 lbs.

stock is about 40-41lbs.

Im going to run the full blown kit on the stock 215s like a madman :(

Tires/wheels should have come first but ill manage somehow.

Keep the nanies on and don't floor it to often, you'll be fine (at least for public roads, the track is a whole different story).

nasa ttd spec = na 205 wide tires on 8x17 wheel
Current spec will run 245 wide street grip tires 225 wide hoosier grip tires both on 17x9" wheels

Robi

I think you will be the first to fit a 275/285 up front.

We are going to try and Ill keep everyone posted. With luck the tires will be here saturday.

Quality of tire > Width.

There are guys running 8's in the 1/4 on a 275, you just need the right 275. Suspension also plays an enormous role in how the car hooks up. Getting the weight to the rear and having the car " squat " is imperative.

I also understand many people want to DD their FI setups and have to factor in wet weather performance as well, which eliminates any real sticky tire.

Tuning solutions such as boost by gear also help tremendously with traction, which would eliminate the need for such a wide sticky tire and maintain decent wet driving attributes.

Many things to consider. Hope I was of some insight.

I'm on the same boat :mad0259:

225 on stock wheels, 11 psi.

Not scary, its fun.

255/40/18 on a 9.5 inch on the rear and its fun and sticks when u make it but if u drop the clutch and launch you will spin :) !!!! Also I have suspension upgrades... I was on the stock rims and tires just for fun and that was a bit scary not going to lie

ORly? You mean it didn't have anything about fitting wider wheels? Think outside of your box, bro.

Uh oh... Should I be concerned about my 235's even though they're ZIIs then? Not sure I wanna swallow the cost of more performance wheels / tires lol.

Yeah, pls keep us posted--will be watching your experiences.

There's direct correlations and then theres 5th generation correlations, this was the later. Even apples and oranges are comparable.

Incorrect. Diameter of the rim (i.e. 17" vs 18") does not affect the tire's contact patch (or "footprint"), unless you install a tire with a larger outer diameter. If you upsize the rim, you should use a tire of the same outer diameter to maintain speedo readings. This of course means the tire will have at minimum a different aspect.

Consider a 4 wheeler as an extreme example, a factory truck may come with 20" wheels and street tires, and have a contact patch the size of a couple baseball cards. The same truck built for 4WD trails might have smaller 16" wheels mounted with gigantic 40" tires that have a monstrous contact patch.

i've been running dunlop direzza z2 245/40/17, on gram lights 17x9 57dr's. No problem hooking up here on map 3.