I just bought a 99 z28 6spd with very little mods (slp loudmouth, intake lid,k&n, a maf I never heard of "delphi",tb bypass, aluminum d-s, and short stick)with check engine light on for cat efficiency codes, Dynoed at "281hp 303tq" and a 14.5 at 100mph only my second time at the track with a stick. Havnt really found the sweet spot yet. Was thinking of adding QTP LT's with QTP Y-Pipe no cats,o2 sims. Not sure what exh to run. keep the slp or?. Ls6 intake manifold, Crane Cam 1.8 Rocker Kit, NGK tr55 plugs, MSD Wires, BMR xtreme shocktower brace, slp sub frames,And 4:10's. good start or no, any ideas would be great, Thanks.

 

No offense but those are some weak numbers ESPECIALLY with those mods. go with 3.73 not 4.10.

 

Word, most stock motors I've heard of have done better than that.

Maybe he's running 87 octane.

 

It depends WHERE he's running. First, it could well be driver related, as he said it's a 6-speed and hes working on learning how to drive it at the track. 2. Some tracks are just faster than others. For example, the track here in Hawaii SUCKS for ET's. I ran 14.4 stock, and am now at 13.3's with LTs, intake, and cam. This is on street tires, but not great either way. Most other F-bodies here run similiar times (with similiar mods) due to the crappy track prep. Hell, even 03-04 Cobras are running 13.5's or worse

So....help the guy out, don't rag him. His dyno HP numbers are consistent with a normal F-body. Mabye he's running 18" rims...like I am.... which SUCK *** (I SAY AGAIN, SUCK ***) at the track. Losing at least .2 from that alone. Might be at 5K feet MSL or 110 degree heat. Many factors make our cars slower or faster.

 

Take a look at JRP's Mod Guide in the stickies.

Step 2 is what you need

 

go with 4.10's since you're a six speed, they will really wake the car up.

Can you give us some details of the track where you run...elevation, weather conditions, etc. How are you launching the car and at what RPM are you shifting? What kind of tires (and what size) are you running?

 

Yes! I ran at New England Dragway in New Hampshire, It was prob 80 or so not too humid. Im running 17" z06 rims w/michelin pilots no drag-radials, my 60' was 2.6 which is horrible and like i said i havnt found the sweet spot yet. I Launched around 2k and was spinning a little bit, shifting around 5500rpm. I'm no stranger to the track i traded my automatic 99 z which i ran consistant 13.4 @ 107 w/2.0 60', for this 6spd figured i needed a change. Was not expecting a 14.5, And a dainty 280hp. But for the mods i am thinking of adding to my car do they sound ok. Oh and ALL those mods that are listed on the bottom in my first thread are what i want to add to my car, only the stuff in the () is what i have done to the car.

 

Ride (read...slip) the clutch out around 2500 RPM, with a quick controlled slip you will easily see a 2.0 60'. And shift that thing closer to 6K. Those two changes alone should get you into the mid 13's.

 

So if I make those 2 adjustments I should make mid 13's or atleast high 13's. You think 280hp im making, sound ok for the little mods I have.

 

Hey man, where abouts are you from? I like to go to NED alot when I get the time too.

You said your throwing a P0420 or P0430 for the cats? That could be a major culprit as to why the car isn't making power (should be making altleast 300-315rwhp on a dynojet). I had a cat clog up and start to break apart in my '00 Silverado. It was choking the truck real bad and the thing just wasn't making any power. If the car has less than 80,000 miles, GM will replace those cats no questions asked under warrenty.

Your 60' is killing you too. Get that down and 13s shouldn't be a problem.

BTW: Don't bother with the 1.8 rockers, they are a waste. I've already been down that road.

 

Yeah NED is a pretty nice go cruize the beach and then go to the track then back. Good times. I'm about a good 1hr 20 minutes from NED Usually go on fridays. Thats what I dynoed on was dynojet at New England dyno and tuning in worcester, MA.

 

Find a stock MAF to put on the car (but for some reason i'm actually thinking you DO have a stock MAF...). Don't do the 1.8 rockers, go re-dyno at a different facility to see how much power the car is making. It could just be where you dyno'd that got you the low results.

 

No i know what a stock maf looks like and this is not one, it says delphi on the side, looks like a granatelli but much bigger. Good thing to hear dont do the 1.8 rockers that will just save me about $1,000. And besides I think the codes im throwing is prob a good reason why its not running full potential.

 

WRONG.....

He has a M6 it comes with a 3.42 rear gear. going to 3.73 will net almost no gain what so ever.

4.10's are a good choice, but i would hold off on the gear swap till you are ready to buy a REAL rear, then the gears come in what ever size you ask for at no extra charge (dont pay twice for the same mod )