Tan327

iTrader: (15)

Went to the track for the first time in 4 years last night and made some horrible passes, looking for some help figuring out these timeslips because I'm beyond confused. Car is an 01 Z28 with I/H/E, tune, 3800 stall, street tires.

Best pass of the night was a 13.80 with a 2.4 60' and letting out early, wish I had that slip but I had to turn it in to make the heads up bracket we were doing.

60' - 2.60
330' - 6.32
1/8 ET - 9.28
1/8 MPH - 85.32
1000' ET - 11.84
1000' MPH - 92.52
1/4 ET - 14.21
1/4 MPH - 81.55 (first time at this track, hard to see finish line, let out way early)

60' - 2.48
330' - 6.48
1/8 ET - 9.74 (Wtf?)
1/8 MPH - 77.36
1000' ET - 12.53
1000' MPH - 87.89
1/4 ET - 14.74
1/4 MPH - 94.04

60' - 2.48
330' - 6.49
1/8 ET - 9.74
1/8 MPH - 77.31
1000' ET - 12.54
1000' MPH - 88.06
1/4 ET - 14.73
1/4 MPH - 94.54

Like I said I'm clueless to a good answer, but I'm thinking the car started spinning again at the 1/8th on the last 2 passes, or was spinning the whole time. To me it felt like I spun out of the hole, hooked a bit, and spun again ..but wasn't noticeable enough to know for sure.

My other thought is that the trans may have been acting up on those last 2 runs, it went into limp mode as I pulled into the tracks parking lot but all was well after letting the car cool down.

Unfortunately I don't have a data logger to know for sure what's going on, but I was hoping some of you experts have a better idea. Any help at all is appreciated!

1Bad97WS-6

iTrader: (3)

First thing I would do is get a set of DR's and head back to the track..Seems like your spinning the whole track.

11SECSS

iTrader: (199)

did you dyno tune the car. I agree you need tires those 60ft are crazy .

Tan327

iTrader: (15)

Yep that's the plan! I thought so too.

Car is tuned by Frost, and yeah pretty much every ones 60' times sucked, even on DR's. Track isn't known for it's prep.

Wire guy

Then get some et streets. You never be able to tell what is going on with it spinning like it is. Hell I got a 1.89 60' out of a stock motored 5-speed mustang with 4.10 gears on real street tires. It looks like you just decked it and smoked the tires all the way down the track. Is you limited slip acting up?

Tan327

iTrader: (15)

It looks that way, but wasn't the case at all. I cut an awful 1.4 light once because I was strictly trying to focus getting the car off of the line. Now I'm not saying I'm some amazing driver, haven't been on a track in 4 years, but I've raced enough to know not to just smash and go on street tires. I'm pretty convinced it spun, caught, and started spinning again once I hit WOT ...then once it finally hooked the 2.73 rear didn't have enough to make up for it. Just my crazy guess. No clue if limited slip is acting up.

Thanks for the replies everyone, looks like the only way to figure this out for sure is buy E.T Streets and make another trip!

1Bad97WS-6

iTrader: (3)

Ya or go to another track if its not to far away. If that track is known not to prep the track to good. I have a stock stall 273 with just Lid/Smooth bellows/Free mods/SLP Y/SLP LM1 and I run on street tires and I leave at Idle and floor it and I have ran a best of 8.6@84mph and 13.20@106mph. Sorry to high jack the thread ..

Frost

iTrader: (45)

With the car off, put someone in it and have them floor it. See if the throttle opens all the way...

Golf&GM

iTrader: (22)

If it feels like the tires are slipping, but they're not, that sounds like a slipping trans.

Midnight02

iTrader: (8)

Yikes -- definitely looks like persistent traction issues through the 1/8, or as Frost suggested, the throttle isn't opening up properly.

got-a-ls1

iTrader: (12)

frost should have further elaborated that when your checking the throttle the car should not only be off but keys removed, in park, e brake set, front wheels choked and rear tires removed and chain wrapped around the rear axle hooked to a tree... safety first...

but seriously running that badly would be ridiculous wheel spin, not just it might be spinning.... Limp mode could be at fault... sometimes a stall makes it hard to notice if its starting in 2nd gear or something.

Tan327

iTrader: (15)

Checked it, it's good.

Now for an update, went to the track again and did better on Nitto 555R's when I did a good burnout, 60' still wasn't amazing but I'm thinking no suspension mods, still figuring out what RPM the car like to launch at, and cut springs could have a little to do with it.

The car is still very inconsistent, it threw a SES light as I was lining up for what should have been a 12.7-8ish pass, it turned into a 14.0. ...14.0 with full bolt-ons, tuned, stalled and a 1.9 60'? Car definitely has issues. The first pass of the night it ran 13.0 with a 2.1 60'. Drop .2 on my 60', add 1 second 1/4 mile. WTF? ..and to top it off, I ran a 13.8 with a 2.3 60'.

I might have the slip to the 13.0 pass tonight, had to turn it for the bracket we were running, hopefully they kept it.

2.31 60' (this pass was my fault)

6.18 330'

9.16 1/8 ET
84.83 1/8 MPH

11.76 1000' ET
91.72 1000' MPH

13.84 1/4 ET
100.60 1/4 MPH


2.27 60' (worst pass of the night, 60' sucked cause of burnout but not as bad as the 13.8 pass so why .6 slower in 1/4???)

6.23 330'

9.47 1/8 ET
78.18 1/8 MPH

12.22 1000' ET
88.95 1000' MPH

14.4 1/4 ET
96.50 1/4 MPH


1.91 60'

5.85 330'

9.10 1/8 ET (this is where the car slowed, almost same ET as the 13.8 pass which had a 2.3 60')
76.66) 1/8 MPH

11.84 1000' ET (worse than 13.8 pass 1000')
89.09 1000' MPH

14.01 1/4 ET
96.66 1/4 MPH


I'm more confused than ever by those time slips, it just doesn't make any sense. The code it threw was for both front O2 sensors being bad, but the front O2's are ignored at WOT, so this wouldn't be the issue right? The trans felt fine and the car doesn't feel that slow going down the track, the time slip just says differently. Like I mentioned earlier the tune is by Frost who has a great rep so I'm guessing/hoping the tune is good. Any ideas at all?

s346k

iTrader: (4)

is this a mail order tune?

when you installed the headers you did extend the o2s, correct? how did you do so?

those times are terrible for those mods and i don't see a 12.7ish pass anywhere in there haha. you've obviously got a problem with the engine management system somewhere, now which sensor(s) it is/are bad is another guess.

transamtom

iTrader: (8)

With both sensors causing a code its probably a dirty MAF.

Tan327

iTrader: (15)

Yes it's a mail order tune by Frost who posted earlier in this thread.

No clue on extended o2's, bought the car with mods installed, I'll check that out though.

Not trying to be an *** lol but yes I know the times are terrible for those mods, that is why I'm here. I had a 4500lb 350whp truck faster than this car, that I sold to eventually buy an F-body to be quicker, so it makes this even more frustrating.

You don't see a 12.7 pass? Car ran 13.0 with a 2.1 60', car pulled a 1.9 60' later = should be an easy 12.7-12.8 if the car had ran the same as the 13.0 pass.

transamtom thanks for the tip, I'll try cleaning the MAF.

Tan327

iTrader: (15)

Installed wideband last week, 15.2 AFR @ WOT.

s346k

iTrader: (4)

uhh that's not good. any vacuum leaks? codes?

and typically lowering your 60' in a stock(ish) car will also lower your trap speed not automatically equating to a .4 better 1/4 time.

Tan327

iTrader: (15)

No codes right now, no vacuum leaks that I know of but I can definitely check. Thanks.

I'd think lowering 60' would still help, I mean it ran a full second slower with a better 60', something isn't adding up.

s346k

iTrader: (4)

any luck?

Frost

iTrader: (45)

That's a dead MAF or having reported an 85mm MAF and then running a stock MAF.

You need to be careful here. There are a lot of n00b tuners that would think that since it's reporting SOMETHING, they can hack the fuel in and you will be good. That will fix things for the moment, but the MAF will continue to report lower and lower though over time.

Your cal is the derivative of over 50 other LS6-f-body swaps and with a properly reporting MAF should put the car in the low 12.s:1 AFR. It's not a borderline tune at all.

To test this, if you have an external IAT (not using a 5-wire MAF) unplug the MAF and check what the AFR in SD is. It should come in nice and fat. If that's the case, you KNOW it's the MAF.