98CayenneT/A

Absolutely severely clogged cats would be capable of knocking 10 mph off his trap speed/ approx. 100whp

Ls1Ryan2002

Something is cutting power for sure, follow the steps Rev mentioned above. Wouldn't hurt to check, after putting on a SLP lid I had the black seal get sucked up into the TB. Went to make a pull and the car fell on its face. Check to see if something is blocking air flow. It's a free way to diagnose an issue.

RPM WS6

iTrader: (3)

The cats probably aren't the problem as the OP hasn't mentioned anything about the engine having trouble revving or being unable to reach high rpms (which would normally be the case with very clogged cats.) It certainly wouldn't hurt to check them though, an IR thermometer would reveal their surface temps but if the clog were this bad they'd likely be glowing red with heat after some WOT action.

As for the tune, it's definitely not a problem with that itself as the OP has mentioned everything is stock.

I agree completely.

And I'm still not sure why folks are recommending a compression test before the basics have been checked. Makes no sense to me at all. Start with the easy and/or more likely causes first. Oops, back to the broken record again. Sorry, couldn't help myself.

Utinator

I did all that, but the gauge didn't hold the reading. It didn't seem to be a good gauge.
I do hang out with an F-body group near Richmond. Most of them have sub-10 sec. cars.
The stock suspension was shot, so I wanted that fixed first. I like my car to turn and stop. You'll have to explain what a "slushbox" is.
I do have new plugs and wires. I'll work on those when I get time. I've been a little busy lately.
I'm changing the transmission, not the fluid. I plan on having a 10 sec, car eventually. Yeah, I have a long way to go.

Utinator

For those wondering, I am an aircraft mechanic. I don't know much about car engines. That's why I'm here asking questions.

JD_AMG

Post a pic of your engine bay, this may help answer some questions. Im afraid we're going to see a V6 in there lol...

99 ss

iTrader: (12)

Lmaoooo that was a good one . I’m dieing to find out to about his car

Z Fury

iTrader: (1)

Going a bit further outside the box - is this a true SS? I'm wondering if this is a stock Z28 converted to an SS and has 2.73 gears in the rear instead of the 3.23. It wouldn't account for every bit of that terrible time, but non-SS gears would not generate the same time as a true factory SS.

I'd want to see a pic of the engine bay as well as a pic of the RPO codes.

RPM WS6

iTrader: (3)

There's only a very small difference in ET/MPH between those two ratios. 2.73 cars will usually MPH in the 101-103 range stock, depending on conditions and such. 3.23s won't bump that range by more than about 2 MPH on an otherwise stock example, if even that.

The OP is missing a ton of trap speed, he's basically in the range of an early TPI 350 3rd gen, which made 230-240hp and trapped in the ~94mph range as well. Something isn't right with the car.

murphinator

iTrader: (2)

fresh air filter , fresh fuel filter , fresh plugs and wires-basic maintenance first.

You said you hang around with some fast f bodies , somebody you know has a scanner and a wideband and can help you get to the bottom of this before you go changing anything else don't add more possible complications.

A friend of mine had a ragtop ss that was stuck in the low 14's @103 stock and it turned out to be running fairly lean , around 14 to 1 air fuel ratio at wot with considerable KR got it in the 12.5-12.8 range and then was able to add in a bunch of timing , also halved all the torque management per the owner he didn't want to remove it all ( I do on my own stuff) bumped up shift pressures and speed/rpm thresholds conservatively car ran 13.3 @109 on street tires after. DR's would have made it a 12.90 car the mods were just the factory ss stuff lid and catback.....

tberg725

As stated above multiple times there is something really wrong with your car, those times would not surprise me out of a V6, with just a dorman intake, 4000 yank ss and a tune I broke into the 12's with a street tire, the best thing you can do is take the advice members have givin you and for ***** and giggles take a pic of your engine bay and post it, I myself would like to take a look and see

Utinator

Yeah, I'm working on that "basic" stuff. These 12-day work weeks suck. Just 7 more months until I retire.

I'm not sure how to post pics here. I know it's a true SS. I can still read the sticker that SLP put on the door.

I'll have to ask "Mighty Mouse" if he can check that for me. I know he has a laptop with some car-stuff software. I guess that's what you would call a scanner. I know he tunes his Vette with it.

tberg725

I did not see this the first time reading threw the post, so what does your engine look like??

Utinator

Completely stock, except the BMR strut tower brace.

Say something about this photo

FirstYrLS1Z

iTrader: (4)

Appears Normal LS1 stock. Throttle body,MAF,OEM filter/intake,traction control.

bammax

Wondering if it's a bad air pump or a leak in the egr. Those could cause issues and aren't the most obvious things. I'd just start with full maintenance and go from there since it's probably been a while since the engine has seen a full maintenance.

Utinator

Well, it's going to EFI Performance (aka. tuned by frost) Monday. He thinks it's the MAF, but will verify. He's deleting the EGR, AIR, and rear O2 sensors. He's also replacing the plugs, wires, 4L60, exhaust manifiolds, and Y-pipe.

Edit: I just found an LS6 intake at my door. Add this to the list of swaps for "Frost". Thanks Mr. Big! (for the intake)

This should be a 12 sec. car when I get it back.

bigbomber5

Nice! Let us know what he they find the problem was

HCI2000SS

iTrader: (2)

It will be interesting to see what's wrong here. Let us know

RPM WS6

iTrader: (3)

MAF problems normally present with some driveability issues other than macro power loss, things like hesitation and odd behavior during certain rpm ranges are pretty common (you had mentioned earlier that the car seemed to run great with no SES light, but perhaps some info has been left out). Some basic diagnostics with a comprehensive scanner and an FP gauge might be very telling.

This should definitely be sorted out before any mods or tuning are done.