Also as injun stated to bypass the throttle body coolant line. What it does is help heat the air going thru the throttle body to improve gas mileage and maybe for economical reasons but it is actually not allowing your k&n filter to deliver the coldest air possible.

Also on race day run higher octane fuel if you don't already.

Sent from my Z796C using Tapatalk

 

My $0.02: Decork the inlet with any of the advertised CAI systems. Get a high flow y-pipe. Do not waste $$ on any type of headers, the stock heads combined with low rpm limiter conspire against any gains with headers. No need for a catback if the y-pipe is good enough (I got zero gain at the dyno before/after Borla catback install). No need for bigger TB or MAF sensor, leave the MAF screen installed. Bypass the TB coolant. Get a 165°F thermostat, combined with any of the aftermarket re-programming tools, start using premium gasoline.

 

You would be better off sticking a tubular K member on it along with a mini-starter if you wanted easier plug and wire access.

IMO if you have a grand to spend and it's an auto do a converter and a set of gears if it doesn't have the 3.23 ratio rearend. Either way budget for a tune for whatever mods you make since it's a 93.

 

The coolant is running through the throttle body to prevent throttle body icing in cold weather/cold climates. Nothing to do with fuel economy. In actual practice, I've never heard of anyone having problems with throttle body icing after removing the coolant flow.

 

I ran a Borla 2 3/4" y pipe, 3" ORP and picked up little power. Went from a 14.10 to a 13.94 in the 1/4. This was on my 95 Formula LT1 automatic car.
Car was very consistent in the 1/4 mile.
Probably picked up a few ponies 7-8 hp. It was a nice sounding mod. Borla does not produce this y pipe anymore. Would have to disagree with the above statement of wasting money on headers. Stock heads respond well to long tube headers and mid tubes. Have seen several LT1s pick up 3 mph and 3 tenths in the 1/4 with just headers alone. So the power is there to
be had. I dynoed 309 rwhp with just headers, 3" ORP, 160 stat and tune. Most stock LT1 M6s dyno in the 265/275 range. I dont think a Y pipe is going to help much to produce those numbers. For what the Borla y pipe cost 169 plus shipping back in 2002. If I would have spent another 150 bucks could have had a set of headers back then. The hassle of the Y pipe install vs headers is about the same...I know I have done both. So how much do you want to spend, determines how fast you can go IMHO. Its all relative. I went with headers on my Firehawk this time and am very pleased with the results.

 

I wouldn't write exhaust modifications off as useless on a stock (or near stock) engine.

WS6.com got 10HP out of the Borla adjustable catback, using the 1.75" plate - dyno proven:

Drivetrain Modifications #5

I did the Borla catback (non-adjustable) and a Callaway Honker at the same time, and picked up 3/10ths in the 1/4-mile. I attributed about 1/2 the gain to each of those mods.

WS6.com also did a dyno test on TTS 1-5/8" headers and 2.5" Y-pipe, and picked up rw14HP:

Drivetrain Modifications #15

GM High-Tech Performance magazine got 10 (flywheel) HP gains with TPIS long tubes. See Test #2 in this article:

Dyno Testing New Mods for the LT1 Motor - Part 2 - GM High-Tech Performance Magazine

 

OP, does your 93 z28 have black stripes down the sides of it and a new transmission in it? auto transmission?

also as far as HP in a 1993, im running a ported intake, TB bypass, 52mm TB, custom grind comp cam, 1.6rrs, bbk shortie headers, off road y pipe, flomaster 3 in catback, 3;73s A/C delete and a few others im forgetting im sure, im planning on having 400HP to wheels from what ive read around and seen, so use what will as a reference from me,

 

I've gained 44 rwhp through bolt-ons. The biggest gain was the was the exhaust. From manifolds with 2 1/2" duals and H pipe to a fabbed shorty header with a 3" collector, 2 1/2" X pipe mandrel bent through 4 Magnaflow mufflers. A 17 rwhp, 16 tq gain. Dyno proven and backed up at the track.
However, none of this stuff is cheap.