New guy here, bringing another thirdgen to the mix - F-Body Road Racing and Autocross Forums

Hello all,
I have been lurking for some time and wanted to introduce myself. I'm an aircraft mechanic living in so cal coming from the drag racing scene. Being originally from south florida, there was essentially no attraction to good handling for me since every road in basically the whole state of florida is straight and flat.
In the past 8 years of living in California I have seen what I can only say is the death of drag racing through track closures, police harassment, etc. This in addition to the magnificent twisties around here has built an itch for me to get into the road racing/ autox scene. It didn't help when a buddy of mine was able to regularly get me a ridiculous amount of free track time at a shall be un-named go kart track. Chasing faster lap times is extremely addicting. Couple this with going for canyon runs in his gutted E36 bmw, and I was hooked.

I previously owned an 89 Firebird from 97-04. It was basically set up for drag. I was very heavy into thirdgens for that time period. That car ended up meeting it's end when I moved on to an 86 T-type which I still own. (It's run as quick as a 7.0@95 mph, 1.54 60' in the 1/8th and should be substantially quicker when I get a working transmission under it).
Even after all these years I still missed my thirdgen, so I decided to go out and buy one. After putting out some feelers, I found a 91 Z28 LB9/T5 hardtop (rear drums (IMG:http://www.frrax.com/rrforum/style_emoticons/default/sad.gif) ) that was pretty rough. I managed to get it home with what felt like 75 hp. After repairing countless atrocities committed by previous owners I now have it running pretty well. Feels like stock with the "upgraded" 2 1/4" kink bent exhaust that some retard put on it. It's my daily driver now, knocked down almost 25 mpg last tank. Unfortunately it still looks like hell. I'll be painting it myself soon.

Anyway, plans for the car are to build it to either STX, STU, or ESP. I am still debating this. In the meantime here is what I have sitting on the shelf waiting for install; complete poly bushing set (will not do both lca ends in poly) MOOG 5664/5665 springs, AC delete heater box (already have the pulley installed), Koni Yellows (on backorder), lt1 ministarter, GTA crosslace wheels (will go with something else later), G.W. Tracklink (left over from the old car, still researching if the short arm is a good idea for what I am doing), 82-83 factory fiberglass z28 hood, hooker headers + 3" y pipe, T-top/vert door shim strikers.

I plan on cutting the springs half coil or so in the front which from what I understand will bump me into the low 800s spring rate wise. To help compensate for the roll center and camber curve issues this creates I'm looking into some taller ball joints (will post about this in the susp. forum). Rear springs will be cut as well. I'll probably start at 3/4 coil for those.
I would love to run a weight jack setup but I wanted to get my feet wet cheaply and quickly.

I'll probably look into some LCA RBs and a panhard relocation setup soon.

Right now I just want to get it to where I can go out and tear up some tires. As it sits, the shocks are so blown that I can induce violent wheel hop (on the front wheels!) with aggressive driving. So I'm taking it easy.

I'll also be applying some of my composites training to the car- I have some ideas (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif)

And yes, from what I've read, some of these mods are probably not technically legal in stx/stu but I think I can fly under the radar locally (don't snitch on me). I would mostly like to be in a challenging class. In judging from local results for ESP, there are basically no competitors in that class or F stock. STX isn't very good either but a lot better. STU has a ton of competitors.
I thrive on competition, I'd rather be dead last in STU with a bunch of other drivers than first in an ESP class with only one or two other drivers.

Anyway, sorry for the book. Check my post on the susp. forum for my ball joint q.
Here are some picts of the cars. The camaro looks slightly nicer now that I've touched up the bare metal the previous owner left from his "paint prep" job.

Buick:
(IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/Barona/_MG_7630.jpg)
(IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/eng-1.jpg)

Camaro
(IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/IMG_0710.jpg)

Josh,

Send me the spreadsheet and I can upload it to the board (assuming it's not over the file limit).

So what is the verdict concerning the Kumho 265/45 xs tires? Will they really fit an 8" wheel well enough to autoX with? Their specs state the minimum size is an 8.5" wheel. What's going to happen if I use them on an 8" wheel?

QUOTE (Pablo @ Apr 14 2010, 10:37 PM)

I would stick real close to the recommended rim widths once you get to a lower profile tire, but for a 265/45 i think they will still be plenty safe on a 8" wheel. It'll probably give up a little bit of tread width due to the pinch and may cause the tire to react slower. For a 16" performance tire I think you'll still be better off with the XS than a crap tire in the right size. I'm guessing you could pick up some 17x9's and have a lot more options for street tires, but the only wheel options I can think of would be pretty heavy.

Kevin, this is quick and dirty spreadsheet I made for doing spring rate/height calcs. For whatever reason it isn't quite right, but it should be able to get somebody in the ballpark on spring rates. Its got all the OEM springs in there as well.

https://spreadsheets.google.com/ccc?key=0Am...1KMGc&hl=en

This post has been edited by roostmeyer: Apr 15 2010, 02:58 PM

QUOTE (roostmeyer @ Apr 15 2010, 07:56 AM)

QUOTE (Pablo @ Apr 14 2010, 10:37 PM)

Thanks for the reply. I also did some searches online and it seems like plenty of people are running tires a little wider than spec for various rim sizes. So I think I will be ok

I was looking at your spreadsheet, pretty cool info on there. One thing that seems like a mistake is that the 5664 and 5662 springs seem to be reversed in their spring rate. The 5664 has a larger wire diameter and is listed at a lower spring rate. Doesn't seem right. I had read other posts on TGO speaking of this apparent discrepancy on the moog spring rate listings. Do you think they screwed up? It would seem so to me, the 5664 is the spec spring for convertables. I wouldn't figure they would use a lighter spring on an even heavier car.

Pablo View Member Profile	Apr 9 2010, 04:31 AM Post #1
Member Group: Advanced Members Posts: 72 Joined: 27-July 07 From: Mascalucia, Italy (Sicily) Member No.: 1,864	Hello all, I have been lurking for some time and wanted to introduce myself. I'm an aircraft mechanic living in so cal coming from the drag racing scene. Being originally from south florida, there was essentially no attraction to good handling for me since every road in basically the whole state of florida is straight and flat. In the past 8 years of living in California I have seen what I can only say is the death of drag racing through track closures, police harassment, etc. This in addition to the magnificent twisties around here has built an itch for me to get into the road racing/ autox scene. It didn't help when a buddy of mine was able to regularly get me a ridiculous amount of free track time at a shall be un-named go kart track. Chasing faster lap times is extremely addicting. Couple this with going for canyon runs in his gutted E36 bmw, and I was hooked. I previously owned an 89 Firebird from 97-04. It was basically set up for drag. I was very heavy into thirdgens for that time period. That car ended up meeting it's end when I moved on to an 86 T-type which I still own. (It's run as quick as a 7.0@95 mph, 1.54 60' in the 1/8th and should be substantially quicker when I get a working transmission under it). Even after all these years I still missed my thirdgen, so I decided to go out and buy one. After putting out some feelers, I found a 91 Z28 LB9/T5 hardtop (rear drums (IMG:http://www.frrax.com/rrforum/style_emoticons/default/sad.gif) ) that was pretty rough. I managed to get it home with what felt like 75 hp. After repairing countless atrocities committed by previous owners I now have it running pretty well. Feels like stock with the "upgraded" 2 1/4" kink bent exhaust that some retard put on it. It's my daily driver now, knocked down almost 25 mpg last tank. Unfortunately it still looks like hell. I'll be painting it myself soon. Anyway, plans for the car are to build it to either STX, STU, or ESP. I am still debating this. In the meantime here is what I have sitting on the shelf waiting for install; complete poly bushing set (will not do both lca ends in poly) MOOG 5664/5665 springs, AC delete heater box (already have the pulley installed), Koni Yellows (on backorder), lt1 ministarter, GTA crosslace wheels (will go with something else later), G.W. Tracklink (left over from the old car, still researching if the short arm is a good idea for what I am doing), 82-83 factory fiberglass z28 hood, hooker headers + 3" y pipe, T-top/vert door shim strikers. I plan on cutting the springs half coil or so in the front which from what I understand will bump me into the low 800s spring rate wise. To help compensate for the roll center and camber curve issues this creates I'm looking into some taller ball joints (will post about this in the susp. forum). Rear springs will be cut as well. I'll probably start at 3/4 coil for those. I would love to run a weight jack setup but I wanted to get my feet wet cheaply and quickly. I'll probably look into some LCA RBs and a panhard relocation setup soon. Right now I just want to get it to where I can go out and tear up some tires. As it sits, the shocks are so blown that I can induce violent wheel hop (on the front wheels!) with aggressive driving. So I'm taking it easy. I'll also be applying some of my composites training to the car- I have some ideas (IMG:http://www.frrax.com/rrforum/style_emoticons/default/smile.gif) And yes, from what I've read, some of these mods are probably not technically legal in stx/stu but I think I can fly under the radar locally (don't snitch on me). I would mostly like to be in a challenging class. In judging from local results for ESP, there are basically no competitors in that class or F stock. STX isn't very good either but a lot better. STU has a ton of competitors. I thrive on competition, I'd rather be dead last in STU with a bunch of other drivers than first in an ESP class with only one or two other drivers. Anyway, sorry for the book. Check my post on the susp. forum for my ball joint q. Here are some picts of the cars. The camaro looks slightly nicer now that I've touched up the bare metal the previous owner left from his "paint prep" job. Buick: (IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/Barona/_MG_7630.jpg) (IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/eng-1.jpg) Camaro (IMG:http://i53.photobucket.com/albums/g71/Chewbaccathedog/IMG_0710.jpg)

trackbird View Member Profile	Apr 12 2010, 01:42 PM Post #2
FRRAX Owner/Admin Group: Admin Posts: 15,432 Joined: 13-February 04 From: Ohio Member No.: 196	Josh, Send me the spreadsheet and I can upload it to the board (assuming it's not over the file limit).

Pablo View Member Profile	Apr 15 2010, 03:37 AM Post #3
Member Group: Advanced Members Posts: 72 Joined: 27-July 07 From: Mascalucia, Italy (Sicily) Member No.: 1,864	So what is the verdict concerning the Kumho 265/45 xs tires? Will they really fit an 8" wheel well enough to autoX with? Their specs state the minimum size is an 8.5" wheel. What's going to happen if I use them on an 8" wheel?

roostmeyer View Member Profile	Apr 15 2010, 02:56 PM Post #4
Advanced Member Group: Advanced Members Posts: 560 Joined: 20-January 09 From: Wichita, KS Member No.: 3,727	QUOTE (Pablo @ Apr 14 2010, 10:37 PM) So what is the verdict concerning the Kumho 265/45 xs tires? Will they really fit an 8" wheel well enough to autoX with? Their specs state the minimum size is an 8.5" wheel. What's going to happen if I use them on an 8" wheel? I would stick real close to the recommended rim widths once you get to a lower profile tire, but for a 265/45 i think they will still be plenty safe on a 8" wheel. It'll probably give up a little bit of tread width due to the pinch and may cause the tire to react slower. For a 16" performance tire I think you'll still be better off with the XS than a crap tire in the right size. I'm guessing you could pick up some 17x9's and have a lot more options for street tires, but the only wheel options I can think of would be pretty heavy. Kevin, this is quick and dirty spreadsheet I made for doing spring rate/height calcs. For whatever reason it isn't quite right, but it should be able to get somebody in the ballpark on spring rates. Its got all the OEM springs in there as well. https://spreadsheets.google.com/ccc?key=0Am...1KMGc&hl=en This post has been edited by roostmeyer: Apr 15 2010, 02:58 PM

Pablo View Member Profile	Apr 15 2010, 07:11 PM Post #5
Member Group: Advanced Members Posts: 72 Joined: 27-July 07 From: Mascalucia, Italy (Sicily) Member No.: 1,864	QUOTE (roostmeyer @ Apr 15 2010, 07:56 AM) QUOTE (Pablo @ Apr 14 2010, 10:37 PM) So what is the verdict concerning the Kumho 265/45 xs tires? Will they really fit an 8" wheel well enough to autoX with? Their specs state the minimum size is an 8.5" wheel. What's going to happen if I use them on an 8" wheel? I would stick real close to the recommended rim widths once you get to a lower profile tire, but for a 265/45 i think they will still be plenty safe on a 8" wheel. It'll probably give up a little bit of tread width due to the pinch and may cause the tire to react slower. For a 16" performance tire I think you'll still be better off with the XS than a crap tire in the right size. I'm guessing you could pick up some 17x9's and have a lot more options for street tires, but the only wheel options I can think of would be pretty heavy. Kevin, this is quick and dirty spreadsheet I made for doing spring rate/height calcs. For whatever reason it isn't quite right, but it should be able to get somebody in the ballpark on spring rates. Its got all the OEM springs in there as well. https://spreadsheets.google.com/ccc?key=0Am...1KMGc&hl=en Thanks for the reply. I also did some searches online and it seems like plenty of people are running tires a little wider than spec for various rim sizes. So I think I will be ok I was looking at your spreadsheet, pretty cool info on there. One thing that seems like a mistake is that the 5664 and 5662 springs seem to be reversed in their spring rate. The 5664 has a larger wire diameter and is listed at a lower spring rate. Doesn't seem right. I had read other posts on TGO speaking of this apparent discrepancy on the moog spring rate listings. Do you think they screwed up? It would seem so to me, the 5664 is the spec spring for convertables. I wouldn't figure they would use a lighter spring on an even heavier car.