Street Racing & Kill Stories - 99 SS vs 99 SS

Hey guys, something is up with my SS. I bought it and all I can tell is it has a lid and a Flowmaster Catback with a detonation problem. High rpm's from 4800 to 5300 rpms. I have tried to remedy the situation, but I think it is the heat here in AZ. In my other thread I raced a new 5.0 and held him at bay from an 80 MPH roll on the freeway until I hit 5th gear. He went around me pulled 3 cars and stayed there until we let out. Those cars dyno 360-370 hp to the rear tires, so I was kinda happy after hearing about that.

So onto my new findings of my SS. My buddy has a 99 SS M6 as well. His has Pacesetter long tubes, y pipe, cut out, spec stage 2 clutch, and a Hurst short shifter. His car was tuned by Arizona Dyno Chip (NicD tunes out of there). He says his car puts down 340/340. I ask if I can take his car for a spin. I drove it and it runs pretty damn good. He will chime in on here and say what it actually put out.

He then drives my car, and is like your car runs pretty damn good for only a lid and a cat back. So I say lets run em. He agrees and we go down to Mexico. To remove the driver mod, we run from second gear at 45 MPH.

We start our roll, and at 45 we both get on them. I pull him by about half car. I attribute this to getting the hit first. However, something strange happens and his SS just stays there. All through second, and all through 3rd, we hit 4th and he starts his creep. He pulls even and we let out...... I was like WTF? That shouldn't have happened, he should have pulled me all the way through 2nd gear, and 3rd gear right? Didn't happen.

We run them again, he honks it off, gets the hit, pulls me by a fender stays there and I miss 3rd. DAMN IT.

We both agree something is up with my car, but what can it be? Maybe a cam? I know my car high idles for a bit before coming down into the 700-800 rpm range when I drive it. It does have a choppy idle, and I swear it is high idling however the tach says it isn't. I attribute that to the Flowmaster Catback. It has stock manifolds, cats, and passes emissions with flying colors........ It should not have run toe to toe with my buddies SS.

So, when I get the cash and time, I will take it to the dyno see what it is putting out. I know he wasn't messing with me, and ran his car.

Why don't you contact the old owner and see if he can shed some light on it? lol

Why don't you contact the old owner and see if he can shed some light on it? lol

I wish I could. From what Carfax says the car has had two previous owners. One owned the car for 2 years and traded it in. It was resold and the second owner owned it for 9 years. It was again traded in, wholesaled at auction, and picked up by the small dealership that I bought it from. The dealership has no previous ownership info on the car. I dont think the DMV would give the info out to me if I asked them for some contact info. I might be wrong...but I really want to know. Who puts a cam in a car, and keeps the exhaust stock? :bang: If this is the case.

So your SS beat your friends' SS?

Have you checked the numbers on the intake? Although unlikely, a ls6 intake and a tune might make up some difference.

If you are having issues with detonation running premium fuel you should get the tune/afr looked at asap. Unless you are running crap fuel it shouldn't have issues unless it has a very lean or aggressive tune.

Just because his car had headers and tune doesnt mean it will outrun one without mods. I had a 408 in my SS and lost to a bolt on Z28 from a roll because my tune wasnt right. I also had a WS6 that went 12.82 @ 110 mph stock. Maybe you just have a strong running car?

So your SS beat your friends' SS?

No, they run about dead even.

I had a TSP 228R cam and had stock exhaust and it ran like a mofo, then added a 125 shot and it was a whole new monster lol.

Have you checked the numbers on the intake? Although unlikely, a ls6 intake and a tune might make up some difference.

If you are having issues with detonation running premium fuel you should get the tune/afr looked at asap. Unless you are running crap fuel it shouldn't have issues unless it has a very lean or aggressive tune.

It is an LS1 intake, and the detonation is from 4800 to 5300 rpm but it cleans up higher in the rpm band. The motor has 145K on it. I put premium fuel in it, and really do not beat on it. It is my daily driver. Only mods are Lid, Flowmaster Cat Back, MSD Wires, and TR55r plugs gapped at .55. MAF is clean, and screened. I want to throw some 100 octane unleaded in her and see if it cleans up. My buddy thinks it has a cam.......

Any chance it has gears in it? 2 friends of mine ran and one had headers and bolts ons untuned, the other at the time just had 410 gears catback and a crappy handheld tune. A 98z and 98 ws6. He actually pulled a little on the header car. What kind of rpms are u turning at highway speed?

It is an LS1 intake, and the detonation is from 4800 to 5300 rpm but it cleans up higher in the rpm band. The motor has 145K on it. I put premium fuel in it, and really do not beat on it. It is my daily driver. Only mods are Lid, Flowmaster Cat Back, MSD Wires, and TR55r plugs gapped at .55. MAF is clean, and screened. I want to throw some 100 octane unleaded in her and see if it cleans up. My buddy thinks it has a cam.......

Ok you say the Maf is clean and screened even if that is the case it could still be your Maf. I had a similar problem my car would break up around 4500 and 5000 eneded up changing the Maf and it ran great.

I would see if your buddy would let you borrow his Maf for a test drive and see if it drives better with his maf. You never know.

I had another odd outcome to a race with a fellow member here, though yours is much more odd.

Mods were as follows:
1998 Z28- 6 SPEED, headers, ORY, lid, muffler delete, 3.73s, tuned
1999 Z28- 6 SPEED, headers, true duals, lid, 3.73s, untuned (+passenger)--mine

Effectively, we had the same mods, him having a tune, me being untuned and I had a passenger while he was alone. Every race we had, I pulled him in 3rd or 4th for no apparent reason. His shifting was on par with mine, it just seemed like mine pulled harder. He even got the hit every time since I couldn't hear his horn. The only thing I attributed this to was the fact that I was on stock wheels/tires where he was on 18s, which could have negated the gearing.

http://www.youtube.com/watch?v=F1Rb9L4p7_A
http://www.youtube.com/watch?v=UYaGiN2Dqcc


Some cars are just stronger than others, but there might be a small issue at play here or you may have hidden mods. Are his shifts slow? That can play a role.

Okay, so check this..... We had a Monsoon sweep through the valley today. I got off work around 11ish and it was 81 degrees out. Pavement was dry so I let it rip, and there was no detonation even when it is at operating temp. None at all. It screamed tonight. I called AZ Dyno Chip earlier today and explained my situation. I am taking my car to them next week. We are going to baseline it and hook it up to see what tune is in it and why it is detonating when it is hot. I am pretty much convinced the car has a tune, cam, lid, and catback. We will find out soon......

Actually you wont unless you pull your cam out and see if its a ls1 cam or possibly a ls6 or other smallish upgrade cam.

yeah both cars we're dead even, mine might've had just a little bit of an edge on his, but not much at all. it was very close both runs. and mine put out 338 rwhp/ 365 twtq. so i'm excited to hear what's goin on with his when he takes it in next week.

yeah both cars we're dead even, mine might've had just a little bit of an edge on his, but not much at all. it was very close both runs. and mine put out 338 rwhp/ 365 twtq. so i'm excited to hear what's goin on with his when he takes it in next week.

Wednesday at 4 we will have a baseline and know why it is detonating.

Any chance it has gears in it? 2 friends of mine ran and one had headers and bolts ons untuned, the other at the time just had 410 gears catback and a crappy handheld tune. A 98z and 98 ws6. He actually pulled a little on the header car. What kind of rpms are u turning at highway speed?

No it has stock gears, we were both hitting our shifts the same time. I cruise on the freeway at 80 around 1700 to 1800 rpms.

Could be a cam. A good friend of mine had a 99 z28 6 speed and they put a cam in it that you couldnt hear. Think it may have been that one thunder racing has, think its called the cheater. Even with catback and tune and a few other bolt ons it didnt sound like it had one but it woke the car up a bunch.

Sure it's not bad knock sensors I had some false knock at 4400rm that cleared up at 5200rmp.

Well tomorrow I pick up an LS6 intake. It goes to the dyno Wed for a baseline. I guess when I do swap the intakes I could replace the knock sensors for just shits and giggles.

Okay, so I decided to set an appointment for the Dyno during the hottest part of the day, on one of the hottest days of the year. 119 degrees during my pulls at AZ Dyno Chip yesterday. NicD came and hooked up HP tuners into my car. It has a stock tune it, and nothing has been changed. It made 293 HP and 307 TQ at get this 14.1 A/F ratio. Stupid lean. So we checked the fuel pressure, it was fine, and now it looks like the MAF is acting up. I have a stock MAF coming from a buddy in Florida, and I might be able to buy my friends Dad's MAF off his 98 Vette to check and see if the detonation goes away.

The real question is, I saw my buddies Dyno sheets at AZ Dyno Chip for his 99 SS. It made 339 hp and 364 tq, so even taking out the driver mod, why does my car run side by side with his? His is a hard top, mine is T-top. My car has less hp, and is heavier yet....... I know for a fact I don't have gears, I was cruising to Tucson last night @ 80 mph at 1800 rpms. I am really confused now.......

Okay, so I decided to set an appointment for the Dyno during the hottest part of the day, on one of the hottest days of the year. 119 degrees during my pulls at AZ Dyno Chip yesterday. NicD came and hooked up HP tuners into my car. It has a stock tune it, and nothing has been changed. It made 293 HP and 307 TQ at get this 14.1 A/F ratio. Stupid lean. So we checked the fuel pressure, it was fine, and now it looks like the MAF is acting up. I have a stock MAF coming from a buddy in Florida, and I might be able to buy my friends Dad's MAF off his 98 Vette to check and see if the detonation goes away.

The real question is, I saw my buddies Dyno sheets at AZ Dyno Chip for his 99 SS. It made 339 hp and 364 tq, so even taking out the driver mod, why does my car run side by side with his? His is a hard top, mine is T-top. My car has less hp, and is heavier yet....... I know for a fact I don't have gears, I was cruising to Tucson last night @ 80 mph at 1800 rpms. I am really confused now.......

Was it the same day he dynod, that you did? If not, then don't worry about it... The Dyno isn't really for comparing 1 car vs another

Was it the same day he dynod, that you did? If not, then don't worry about it... The Dyno isn't really for comparing 1 car vs another

It wasn't dyno'd the same day. I don't know when he dyno'd it, might have been in the cold season here......

He is going back next week to see what it pulls. Hopefully it will be 110+ out so we can have kinda the same atmospheric conditions.

Yea you never know - software updates, if the dyno was serviced, different weather, etc... anything can impact the #s. Just be glad you found out it was running super lean and can fix it. Previous owner may have had other mods done and you are running stock(ish) on an aftermarket tune (unless you in fact confirmed its 100% virgin PCM)

It is a 100% virgin PCM.

Okay, so long story short it was the MAF sensor. I switched my stock one out ( I also threw my K&N in the trash, and bought a Fram air filter), and bought a MAF from my buddies dad that came off his 98 Vette. Installed it, let it idle for 3-4 mins, drove it normal, then beat on it getting on the freeway. No detonation, full pulls through 2nd, 3rd, and 4th gear all 6400 rpm. It is running great now. Looks like I will be heading back to the dyno next week, and I will have a re-run with my buddies 99.

Okay, so long story short it was the MAF sensor. I switched my stock one out ( I also threw my K&N in the trash, and bought a Fram air filter), and bought a MAF from my buddies dad that came off his 98 Vette. Installed it, let it idle for 3-4 mins, drove it normal, then beat on it getting on the freeway. No detonation, full pulls through 2nd, 3rd, and 4th gear all 6400 rpm. It is running great now. Looks like I will be heading back to the dyno next week, and I will have a re-run with my buddies 99.

Awesome!! Good luck at the dyno, and get vid of your rematch!

Whoever is in that black car shifts slow as hell. Needs a driver mod for sure.