For example, if I wanted to run 28.2" diameter tires rather than the 25.7" diameter tires that the X has on it?

All this would really do is correct the speedo. I suppose, for track use only, I might not even want to. However, still interested in the answer.

Thanks.

 

No.

 

Thank you for the concise reply.

 

No sweat.

 

+if you go that 'tall' they will surely rub badly. I went with a 45 series for the street (1" taller) and they rub on lock to lock. Any taller than that and they woud'nt fit anyway

 

MooseX, I only plan on running them 1/4 mile at a time. Or actually, a 1/2 mile, that's a 1/4 down and a 1/4 back. Only big turn on a drag strip is the one onto the return road, and that's normally pretty manageable.

Appreciate the input though.

Right now with the 245 40 18 tires (25.7" diameter), the EvoX will go through the traps at about 112 mph, assuming a 7500 RPM rev limiter. At 8000 RPM (assuming RPM is increased via a flash) it can go through at 119 mph.

With a 27.6" tire (235 50 18) same engine speeds:
7500 = 119 mph
8000 = 126 mph

With a 28.2" tire (235 55 18) same engine speeds:
7500 = 123 mph
8000 = 131 mph

Ultimately, I plan on getting into the 125-130 mph range, necessitating either the tires or different gearing. Tires are cheaper and more effective at launch, since taller tires hook better than wider tires. Whether I run 28.2's or 27.6's will remain to be seen.

 

If your car ends up being 130mph capable someday down the road, you might as well just accept the fact that you'll have to shift to fifth unless you want to spin it to 9k.

 

But with the 28" tire, I might not have to. Assuming it all fits of course. Maybe it won't. In a straight line, I can't see how the taller tire would be an issue. I don't plan on lowering my car, and from the times I've been under it, there appears to be plenty of room.

Who knows, maybe at that point the car will be faster shifting to fifth, but nearly every seemingly realistic shift point scenario I run going into fifth, puts the car in fifth for only about an increase of 10 mph through the end of the track. I can play with the numbers and make excel say I'll pull a 30 mph speed increase in fifth, but I don't think that's realistic. For only a 10 mph gear speed increase seems like it's not worth shifting to fifth, hence the taller tire.

This is ALL speculation and calculation of course. If/when I get to this point (or even someone else), I'll know for sure. I'm an independant, I'm sure a shop car will run into this problem long before I do.

 

so this is just a what if question because even if you could change the speedo you wouldnt because it would be off for regular driving on stock height tires

 

LOL. YES. My original intent was to change the ECU setting, but after typing the first sentence, I came to the exact conclusion as what you typed, changed my ming, but hi the submit button anyway just to know the answer.

 

We're off topic anyway since you got your original answer, so why not continue? Due to power and weight, a normal weight Evo X will need about 600whp on a Dynojet to trap 130mph.

In a two liter, that means you'll need at least a 35R. It also means that you're going to need to rev it pretty deep. Maybe not 9k deep, but close.

All this to say, if you're going to be making that kind of power, you'll be making it way up in the rev band, and your transmission issues will cure themselves.

If you make a lower revving stroker, just have a new FDR put in there when you pull the motor. Making an Evo X trap 130mph is going to incur a lot of worries that you'll prioritize ahead of oversized tires rubbing.

 

5th gear is free last I checked

 

I had figured it would take a turbo that can flow about 65 lb/min and 35-ish psi manifold pressure for a 128-130 mph trap in an EvoX with a 3700 lb race weight. If a GT35R can do that, then I suspect that's an option. In the past I ran a Master Power T70 and then a PT76 on a Mustang. Most of my experience is with aftermarket turbos. I understand Turbonetics has a new GTK series turbo which works pretty well also. I have no aversion to a Garrett turbo, but my past experience says that the aftmarket companies normally have more options for A/R ratios on both turbine and compressor. I do want to stick with a twin scroll unit, so if the aftermarket companies don't have that option, I'll prob stick with Garrett.

Really, I may be confusing the issue here. What I really want is a car that goes 10.70's-10.90's. In a manual trans Mustang on drag radials, where most of my experince lies, that car better be going 130-ish mph. An AWD Evo probably won't have the traction problems a manual DR Mustang has, but I don't really know yet. If an Evo hooks up better (and the DSM's I saw back in my Mustang days sure did) then I probably don't need to be going 130 mph. Frankly, if Big Valley can go 11.40 @ 115 mph, maybe a 10.70 car going to fifth only needs the power to go 122-124 mph. Only time will tell given this platform is completely new. Also, I suspect by the time I've gotten this all together, I'll have pulled a bunch of weight out of it, making my 3700 lb race weight mega-portly (I hope).

I bought this car because I wanted something different and new compared to what I had previously. I can throw together a 130 mph Mustang with no problems, using "not so trendy branded" used parts, for probably somewhere near $15k. I don't really want another one of those. I like fabricating stuff more and learning new things more than just assembling someone else's purchased parts. This is the reason I bought the X. It's completely new, and there aren't many independants working on it with intents to campaign a serious effort.

Anyway, really off topic now. Continue if you want.

 

My 45 series BARELY fit. It's the back edge of the tire that has minimal clearance. The front edge has plenty of space. I have about 1/2" clearance remaining on the rear of the tire...

 

Damn... Haven't spent much time looking at the back of the tire.