DSC

Looks like I might pick up the new car next week
After reading over the rules I was left with a few questions, hopefully you all can answer them for me, or point me in the right direction to have them answered.

The front tension rod on the 240sx goes bad I think the day it leaves the factory, honestly, they suck. The bushing is a very hard ruber (think street tire compound hard) injected with a silicone goo. The ruber rips easily because of the suspension design, asking a part to move in 2 directions but only building the part to move in one so the bushing rips and the goo leaks out, giving the front end a lot of 'slop'.
Finally to my question, can I replace this bushing with a solid polyurethane bushing and still be in g-stock? Or does that bump me to sts? Same amount of metal, same amount of bushing, same actual suspension piece, just different material bushing and no silicone.

Shocks, specifically looking at koni yellow. Rebound adjustable only, static compression. Rebound is adjustable I think 8 different settings of hardness. This is OK for g-stock right? It says no more than 2 adjustments in the rules...(not sure what adjustment the rules are talking about) do koni's have 1 adjustment or 8?

Sub frame bushings, same type as tension rod bushings…rubber with silicone goo. Can I replace them with poly bushings?

Is brake ducting allowed? Do temps in auto-x get up high enough for it to matter? If ducts aren't legal for g-stock, can I still have ducts on (for track use) and just tape them off for auto-x? Or will I actually have to remove them for auto-x?
Any rules about removing the dust shield behind the rotors?

Wheels - Any wheel the same diameter, width and offset as stock allowed? 15x6, would be nice to find some that aren't steel if I can. I think this is what I read, just want to double check.

"Engines may be rebored to the manufacturer's first standard overbore, not to exceed 0.020"
Is this anywhere within the range specified in the factory shop manual, as long as its not more than 0.020 beyond the largest size in that range?
Won't get beyond the head for a long while, but figured I'd go ahead and ask.

On a 12-year-old motor, the head is going to be disgusting. Is minor sanding (porting/polishing whatever it’s actually called) of the exhaust ports allowed to clean carbon buildup? If not, what’s the best way to get it back to stock flow?

Welded or bolted in roll bar with diagnal brace from the main hoop above the driver to the passanger side floor (attached on the bar, actually a few inches up from the floor) and horrozontal bar for a harness is allowed right? What are the rules on cutting/removing interior pieces at the bar's attachment points?
If I read right, I can use any aftermarket harness so long as the stock 3pt is left in right?

"Any item that can not be held permanently in place by factory installed fasteners may be removed. "
This is kindof vague to me. The board over the spare tire just sits there. All the other pieces of material in the trunk are held in by clips, a hard tug takes them off, and a smack of the fist puts them back on. What can/can't I remove here?

Can I remove the speakers and tape deck? All associated wireing?

Updating/Backdating:

The 89 240sx and 90 240sx had different compression pistons.
Can I put the higher compression pistons from the 89 in my 90?
I'll have to do more research but I believe everything between the 2 motors is exactly the same except for the pistons compression ratio.

The SE model of the 1990 240sx had ABS/LSD as a package option. The car I'm getting doesn't have that option; can I add the LSD from a car that had the option?

Don't think I'm doing all this at once, just figured I'd post it all now and get it out of the way.

All I can think of for now.

Thanks in advance!
Dave-

monaco

Bushings must be the same as originally equiped
Konis have 1 adjustment w/8 settings.
No ducting for Solo 2, you must remove for auto-x. You can not remove any part of the brake sheilds.
Wheels-pay attention to offset. 15x6 is a hard size to find. SSR Comps or Volk TE-37s or CE28Ns $$$$$$$$$.
You can not overbore beyond .020"
No head work allowed.
Roll bar must have four mounting points.
In the trunk you can remove the spare tire and the jack along with any tools. If the board has no fastener it should be removed to pass tech.
Removing the raido is legal IF you could buy a 90 240 WITHOUT a radio and speakers. The trick is if the radio is part of an options package, everything in the package must be removed. i.e. air conditiong and radio bundled together the AC must come out as well.

DSC

Heh, shattering my dreams here monaco thx for the clarification. Good news on the koni's tho.

lightningd

for the reality check though, lol

don't tell anyone about the bushing. it's not gonna make your car go that much faster, and it will save you $$$ and life of your car. go w/ the poly bushings.

koni's are fine. basically, the only change the strut should give you is up/down compression effect. nothing else should change.

as for the valves or whatever. cleaning your engine is OK.

DSC

I guess as long as I don't win nobody will protest...but then again, I just told everybody about the bushings so it's a little late for hiding it And your right, it won't actually make the car any faster. I put solid metal ones on my 96 and it just made it feel better, not really go any faster.

One question I forgot to ask was about exhaust. In my other post someone said I could swap exhaust. Well, right now the car doesn't have a muffler at all and for whatever reason the exhaust it totally gone from the pre-muffler (resonator, whatever it is, 1/2 way between the cat and the real muffler) back, so I'm going to have to replace it.

"Any part of the exhaust system beyond (downstream from) the header/manifold or catalytic converter, if so equipped, may be substituted provided the system meets the requirements of 3.5. Stainless steel heat exchangers are permitted only if the physical dimensions and configuration remain unchanged. "

So I can do anything I want beyond the cat, as long as it's stainless steel? What's the 3.5? Max size or a type of steel?

monaco

3.5 is a section of the rules, I'm not exactly sure of the wording, and my rule book is at home. Anyhting downstream of the cat is "free"- but the exhaust must terminate behind the driver (this may be in 3.5-I'll check tonight). Using this reasoning, any pipe may be considered a muffler so a straight pipe can be your muffler system as long as it terminates dehind the driver. The material for the muffler is unspecified as well as dimensions and sound deadening, the limiting factor will be the openess of the cat anyway. A 5" pipe downstream and connected to a 1" cat is not very effective. Just remeber some back pressure is better than none.

roadRacer

It all sort of depends on your level of seriousness.

At the local level here around Tidewater at TSCC events some of the things mentioned are not legal. I think Monaco pretty much gave you the letter of the rule...

Locally, expecially if you tape up the ducts, nobody is going to complain about them. If the wheels are the stock diameter, width, and offset (+-1/4"), you are ok. The rollbar has to be no more than a bolt in 4 point bar. The TC bushings are probably the worst violation you mentioned. I would probably run with the car in stock at local events, get to know the competitors in your class, be completely honest with them about the mods. If any of them complain significantly, just chose to run in the appropriate Street Prepared or STS class.

Now if you plan to go to national level events, and hope to win trophies..... you are going to get protested with those modifications. The competitors are serious, and sometimes at the pro events the money paid out can be pretty serious too. I think at a single event there has been a payout of more than $10,000, so if you win, expect your car to be closely scrutanized. Think about it, knowing that you are running against people in your class and knowing that maybe a full set of autocross tires was on the line for the winner..... think someone would protest the existance of brake ducts, even if they really make no differance in an autocross..... Or if you won by 0.01 second, think someone might think maybe, just maybe that was the differance?

roadRacer

On exhaust.

Some event sites have sound level rules. If your car is determined to be too loud, you can be either not allowed to run, or DQ'ed, no matter what the exhaust consists of. I think with the stock cat, you don't really have to worry about being too loud anywhere, but it is just something to note.