RAGEman

iTrader: (4)

As I posted earlier in the week, I'm trying to fit some 28" x 10.5" x 15" ET Drags on 15" x 10" (w/ 7.5" backspacing) Weld Draglites underneath my car. I am using wheel spacers that I believe are ¼". I don't know for sure because they've been sitting in my garage for nearly 400 years, and I can't remember anything further back than 48-72 hours. Saturday was SUPPOSED to be track day at Temple Academy Dragway, but alas, of course, since I had a desire to go to the race track, it rained. So we used the rest of the day for some more track preparation for next week. After a little bit of grinding on those pesky rear brake calipers, they fit in there. We're talking a fraction of a fraction of an inch of clearance between the rear of the tire and the rear bumper cover. Well, me being the moron that I am took the car out and did (after many failed attempts to keep the car from sliding around all over the place) a monster burnout on a side street next to Nitro Dave's (one of our sponsors, BTW) shop. Everything was just great after I finally got the car to stay put and I did a very large burnout. The tires were at that point about .00000000000001 millimeters away from hitting the rear bumper cover. I then attempted to launch the car from around 4K RPM's several times, and spun each time, of course. What with me being on the dirty, cold street and all. Anyway, after pulling back into the shop we took off and inspected the ET Drags. We noticed a distinct line that had been rubbed around the tire, and upon inspecting the fender ABOVE the tires, found rubber marks on the white paint. Is it possible my car squats so hard, even on the street, that the fender comes down so far that it rubs the tires? I figgered the problem would be with the rear bumper cover, but we noticed no rubbing lines on the tires from that. At that point, I was advised to roll the edge of the fender that sticks out inward towards the interior of the car up all around the upper quarter panel, I guess it's called. I also see part of the rear bumper cover that can easily be sliced off just in case. We will be attempting these modifications this week and I'll be sure to let everyone know how it goes.

On a side note, I was informed last night that when the tires "grow" towards the end of the ¼-mile, they grow up-and-down, not side-to-side. What are your thoughts on this?

Any comments or insights will be greatly appreciated.

It'llrun

I thought wheel spacers were against track rules all over? They won't likely check though.

Tires definitely grow vertically and narrow horizontally at speed. The same thing happens when you do a burnout. You won't notice that as much with ET Steets as with ET Drags, though it still happens.

SilverGhost

iTrader: (53)

the problem you are having right now is being caused by that spacer you are running. believe it or not, 1/4 is way to thick..you could roll the fenders, but the simpler solution is to grind more off the calipers.

pull them off the car and let at them with a bench grinder.

the best way i can describe this job is aggravating, boring, and a total pain in the *** that will take a long time to get it right.

but if you want the tires to tuck in under the lip you have to do it. its hard to believe just how much metal has to come off those things before they will work..trust me its alot.

i broke through my caliper from grinding so much and said **** it and put tiny 1/8" or so spacers in and the tires still just clear and don't hit when they expand, but no spacer at all would be ideal.

i also had to trim my rear bumper a bit on each side to keep them from hitting in the back.

I personally wouldn't want a spacer as thick as 1/4" either running a 28" Et Drag..makes me a little nervous taking away that much thread when running tires like that.

as for squatting..mine does that pretty well..pulls both front tires at the track..but i'm not hitting with the way i have it now. I even pulled out the donuts at the top of the springs and put radiator hose in instead to lower the rear and there is still enough room..the key is just to get the tires tucked inside the fender so they clear that lip when the car sits down or the tires expand at the big end.

hope this helps.

Sean
A.R.T 98 Z28 A3
03 Impreza WRX

SilverGhost

iTrader: (53)

oh yeah, one more thing, i assume you have an adjustable panhard rod. make sure that rearend is dead ***** centered before you start the process of grinding, testing, gridning some more, etc. otherwise you'll end up driving yourself crazy when you put the car back onthe ground and one side clears and the other doesn't and you have to start over again.

center the rear in the air..drop it and it WILL change. so note what you have to do..put it back in the air, adjust, drop again..till its dead ***** on, lock it in..and then start the grinding process.

that's what i did anyway, have fun <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

RAGEman

iTrader: (4)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by It'llrun:
<strong>I thought wheel spacers were against track rules all over? They won't likely check though.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I think they just might be. But, I can assure you the track I go to won't check. <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

SilverGhost, thanks for the help, partner. I've got a whole week, so I just might do some more caliper grinding. One thing I cannot afford to do is break through the caliper(s). I'm not entirely sure if my spacers are 1/4-inch or what. I originally thought they were 3/16-inch, but I'm just not sure. If they are 3/16", that's only a sixteenth of an inch wider than yours. Where does one get an 1/8-inch spacer from anyway?

Unfortunately, I do not have an adjustable panhard rod. I'd really like one, though, along with adjustable LCA's, and an adjustable torque arm. I wish I had a little more money. That or less bills. <img border="0" title="" alt="[Embarrassed]" src="gr_emb.gif" />

Pro Stock John

iTrader: (34)

My 28x10.5x15 Hoosier slick/15x10 Pro Star (7.5) has never rubbed. I don't have rear spacers. My car torques over to the passenger side too... It's the spacers. I think spacers in back are dangerous, especially big ones. Just grind carefully... fit and grind, fit and grind. It's not hard, it's time consuming.

My old 28x11x15 MH's on 15x8's rubbed on launches and that's due to how much the tire sticks out with those 15x8's... I think the Centerlines would be much worse.

RAGEman

iTrader: (4)

Okay, another question then: how do you know how much is too much to grind off the rear calipers? I don't mind grinding, I think it's fun. I just need to know where to stop. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

RUQWIKR

iTrader: (11)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by RAGEman:
<strong> Okay, another question then: how do you know how much is too much to grind off the rear calipers? I don't mind grinding, I think it's fun. I just need to know where to stop. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" /> </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Check your wheels side-to-side. I've got a couple of sets of ProStars and they varied wheel-to-wheel. Also, on the 28's, my M/T (10.5's) grew a bunch. I could stick my finger sideways in between the tire and the fascia only to have them rub quite badly from about 1/2-track on. I trimmed a bit and bent back the metal behind it, but they still rub a bit. That'll change before I'm back in action when the snow melts, hopefully, by April 1st or so.

BIGBOS

I'm running 27x11.5x15 Hoosier QTP's, I have some rubbing issues with these, I have 15x10 prostars in the back...the grinding was a pain in the ***.. <img border="0" alt="[bang head]" title="" src="graemlins/gr_banghead.gif" /> but well worth it, I have eibach lowering springs in the back, that I will soon replace with regular v8 springs.... <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" /> that will help some...my tires rubbed the inside of the fender well, but I fixed that by pounding with a hammer, the bump stops were rubbing, I completely grinded those away....now I'm just having the rubbing problem on the upper lip of the fender...whats the best way to tuck that under?

Jason99T/A

iTrader: (21)

Alan,

I had to do quite a bit to get my 28" Hoosiers and M/T ET Drags to clear using Weld 15x10 Prostars.

First off, I had to totally remove the bump stops and grind the mounting points down flush with the rest of the car. This gave me much more clearance inside the fender.

Next, the tire was practically resting on the rear bumper fascia. I pulled the plastic back and secured it with some self-tapping screws. This worked very well and wasn't hard to do.

The Prostars required alot of grinding, but fit very nicely in the end.

Here are some pics of the car w/ the 28" Hoosiers (now running M/T ET Drags):

http://members.***.net/jason99ta/28fit.jpg
http://members.***.net/jason99ta/28fit2.jpg
http://members.***.net/jason99ta/28fit3.jpg

Here are some videos with the 28" Hoosiers from Memphis this summer:

http://members.***.net/jason99ta/jason11481.mpg
http://members.***.net/jason99ta/jason11484.mpg

I do hook way better on the M/T 28" slicks FWIW.

Jason

BIGBOS

What kind of springs are you running in the back, you have more clearance than I do w/my 27" Hoosiers

Jason99T/A

iTrader: (21)

I have stock springs in the rear. However, since those pics, I have removed the rear spring cushion and this dropped the rear 1" and caused alot more clearance issues when I put the 28" M/Ts on there. It does look 100 times better though lowered.

BIGBOS

Yea, mine looks great how it is now, but as soon as I launch it they will rub, it can also get bad if I carry one person in the back...

SilverGhost

iTrader: (53)

Yeah, forgot to mention those damn bumpstops.

i just got out my trusty cut off wheel and compressor and cut the whole mount off so the tire would not hit inside the fenders. strange thing was that even with the rearend centered right on, i had to cut more off one side than the other so all would fit..but whatever

BIGBOS

Yea, I also had to cut more on one side, I still need to do some more grinding, I will worry about that when it gets warmer out.. <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

Bob Cosby

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">On a side note, I was informed last night that when the tires "grow" towards the end of the ¼-mile, they grow up-and-down, not side-to-side. What are your thoughts on this?</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Correct. Your 28" slick will become taller as speeds increase. How much will vary on a number of factors, including wheel width, tire pressure, and speed of the car in the traps.

Pro Stock John

iTrader: (34)

IMO you didn't need to cut off the bump stops, the tires only hit them when you jack up the car and the rear end is not supported.

I just bent mine back and took the snubbers off and they never rub.

A finger of clearance is a must between the tire and the body panels.

Bos if you removed your rear spacers you would not have any contact my rears are bigger than yours and they never contact.

Rage, try making the face of the calipers with marker or black grease... tq the wheel down... rotate it, and then see where it's contacting... It's not hard.

dug

iTrader: (10)

How about removing the rear brakes? That should take off 50 pounds of unsprung weight.

SilverGhost

iTrader: (53)

TheVenerableProStockJohnson--mine were hitting on those bumptop things even with the car down on the ground..and just trimming them left barely enough room..made me too nervous. Was worth the 1/2 hour it took to just chop them off to know i'm not going to shred a tire and hit the wall

Jason99T/A

iTrader: (21)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SilverGhost:
<strong> TheVenerableProStockJohnson--mine were hitting on those bumptop things even with the car down on the ground..and just trimming them left barely enough room..made me too nervous. Was worth the 1/2 hour it took to just chop them off to know i'm not going to shred a tire and hit the wall </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ditto!!! <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />