Originally Posted by
SMWS6TA
Best thing that you can do for a 98' is fix some of the common issues so that when you start putting power you have a solid foundation.
Common problems are:
Passenger Window - Autotrix (Sponsor) sells a fix for it. GM routed the hot wire through the drivers side. By the time it gets to the passenger motor it is no longer 12 volts so the motor is under powered and ends up burning out quickly (Cost under $40)
Oil Pump - 98's have (in a word) a crappy oil pump. Over time it flow drops off and leads to failure. When you replace it get at least a LS6 oil pump, it will increase the flow and keep the pressure up (Cost $110, ported $170)
SFC's - like previously posted, these cars should have had them stock. More power you add the easier the body will flex. 2 points are good, 3 points are better. If you have a vert, I recommend only getting 3 point.
Rear Ends - This is our cars greatest weakness - Over 420RWHP it's not if but when your rear will go. A4 = 12 bolt, M6 = 9" works well with these. Gears = personal choice and what you plan on doing.
PCV Issues - I've been told I'm very passionate on this issue. I F'ing hate the OEM PCV system. It's crap is a nice statement. OEM replacement cost $85-130 to replace. With some time and patients you can replace it with a better system. Look up LS6 VCT mod, combine this with a catch can and you'll have a better solution for $60.
Knock Sensors - 98 KS are no longer made. You will need to up them to the 99-02 KS and WH. You usually do this in conjunction with a intake swap or while doing the LS6 VCT mod.
Free Mods - You can get some performance and function mods without spending much money. It is mostly time. LS1howto.com and our tech sticky section has a lot of them.
Bolt ons - Most bolt ons are about $500 and under. Some things you can get from here in the "parts for sale" section, ebay, or craigslist. I got my LS6 Intake and P&P TB for $450 together.
Most upgrades are:
Ls6 intake or Fast <they are getting harder and more $ to get)
LT Headers - Pacesetter and EBAY headers are very affordable and have had good reviews from members here.
ORY - I'm running TS&P with my Pacesetters and it was very affordable.
Muffers - Everyone has their own tastes, I'm using Magnaflow because I like the rumble, were Flow Masters has the rasp.
P&P TB - I would only recommend spending the $$ on a new TB is you had a FAST 102 intake to go with it. You can get P&P TB for under $150 and have very close to the same results as a 80-85 mm BBK TB that goes for $350.
A4 - Stall coverter
M6 - under 450 RWHP or min track use go with a LS7 clutch Kit, Heavy track use, go with SPEC or Monster clutch systems
Cam and Heads - again these are a personal choice and require tuning. Cost for both can be around $1800 to $3000 plus a dyno tune $500.
Wheels & Tires - personal choice.
What I tell new owners that want to start a project is that the end result is from a lot of many little projects. Research what you want, write it down (map it out), ask questions. Know what you can do, are willing to do, and can not do.
The route most ppl will suggest is to fix what needs fixing 1st, then suspension, rear, drive train, with body and paint last.