Potent68

Absolutely! I'll probably still cut pretty awful 60' times on my Bridgestone Potenzas and my lack of experience launching the car, but I'm very curious as to what it will do to my trap speeds. I'd like to try it again before it gets much warmer too.

racebum

that re760 is such a terrible tire. best i was able to do on a stock z06 with that tire was a 12.6@115.6 @ pir which has no prep at all. basically street racing. hard on the clutch too. in order to even get that i had to slip and launch

when i first bought my 02 it came with a new set of those which were quickly replaced by 18/19 wheels and michelin pss tires. those things are amazing

had the t1s been available back then like it is now i may have kept the stock wheels. the pss is still better but at least the toyo t1s is a good tire for here in the NW that comes in OE sizes and actually works well.

our local discount tire stores can get you fixed up with a set of those. nt05 is another choice but it's scary in the rain

Potent68

That's good to know. I'll definitely keep that in mind when I need to replace these tires. I thought about just buying a cheap set of wheels and slicks to go drag racing with but then I'd need to rent a trailer every time I take the car to Woodburn.

In other news, the air cleaner assembly will be here on Friday. I'll probably get that, the MAF cleaning, and the fuel filter done Friday night or Sunday.

AmbulanceDriver

Thats interesting, just put a blackwing intake from slp on my car and have the same exact codes. Also did x-pipe and back exhaust. Cant find a vacuum leak, used the cigar smoke method only smoke that leaked came from the filter...

racebum

that is suspect. both of you, same codes. same filter.

i have ran a couple pasees with no filter just to try it but it was a different day, different weather and just a 1/4 mile pass

i've never heard of JUST the air filter causing a lean condition but turbulent air or something that filter is doing may be screwing with the MAF

very suspect you guys have the same filter and same problem

Potent68

Have you tried putting the stock air cleaner assembly back on and seeing if it clears? I cleared mine at the track and after driving back home mildly and to/from work mildly it hasn't come back on. I'm sure the issue still exists as I was getting the hesitation in 3rd prior to the CEL coming on.

AmbulanceDriver

I trashed the stock one. Got picked up a say before the code came on. I didn't have to code till I had an oil change done the next day. Now it won't go away. Cleaned the maf too.

Potent68

UPDATE.....

I just swapped the fuel filter, cleaned the MAF, cleaned the throttle body, and installed the stock air cleaner assembly. Unfortunately it still doesn't feel right. It almost feels like it's missing at higher RPMs, but it's not setting any codes at the moment. I guess it could be a bad spark plug, a weak fuel pump, or a weak coil. I'm not really sure which but I do have a set of NGK TR55's that I bought for it when I did the valve springs so I may try to install those in place of the original iridiums.

Any other ideas?

bwill03z

What octane gas do you use and do you get gas from diff stations or one in particular? I always run 93 octane and try, when possible, to avoid ethanol gas. Do you think your cats are clogged?

Black 03 Z06

Some great discussion here. May I ask what your method of launching the car is?

Will keep an eye on this thread to see a positive outcome, hopefully you can get it sorted quickly with minimal expense.

bikeriderga

Tuning the car will remove what you felt up top. Not suggesting you pay for a 500.00 dyno tune, but your should be able to get a street tune for around 150.00. It will definitely improve your performance.

Potent68

I use premium. I couldn't tell you off hand if that is 91 or 92 here, but I get it religiously from the Fred Meyer (Kroger) gas station. The cats *should* be good with only 10k miles on them but it's something to keep in mind for sure.

Potent68

I didn't mess around with tire pressure (which I should have) and I was just trying to launch smoothly at various RPM's. Dropping the clutch to quick resulted in hopping and spinning. I was spinning the tires enough to clean them off but never got the smoke rolling off of them. Once I have the performance sorted out I'll go back and try to imitate the Ranger method. That or find a cheap set of wheels and slicks that I can bolt on for the drag strip when I go.

I think I ordered the TR55's prematurely. There seems to be a mess around which plugs are specifically recommended (for stock cars) from GM now. First they had whatever the original platinum plug was. Then they released a TSB (03D-J-171) citing that there is a new revised iridium spark plug, ACDelco 41-985 that is now gapped to .040" instead of the previous plugs .060". Then I saw a bunch of people talking about running the ACDelco 41-110 iridium plug now. Even the ACDelco parts looker upper said the 41-110 is for 2005 and newer cars and pointed at some different plug number for the '01-'04 cars.

Finally I kept digging this evening and found that the 41-110 superseded the 41-985. SO, I ordered a set of 41-110's and they will be here on Sunday. That works since I won't have much time to mess with it tomorrow.

Doing a search on here for the right plugs can be confusing as hell!

Potent68

The problem is that until it's running like it's supposed to be in stock condition, a tune will not be able to optimize it. Kind of like putting a bandaid on a broken arm. I want to fix the broken arm before I start lifting weights to make that arm stronger.

MY03C5Z

You really don't need to heat regular street tires up until they smoke on your burnout. With my NT05's I drive around the water box, then back up into it, drop the clutch in 2nd and roll into the gas to 4-5k for about 2 sec until they bite, which is real obvious to feel when they grab on the dry pavement. Get to the line quick and stage very shallow, dont be the last one to stage. Gives you more time to prepare, that's what I do every time. Your mph was low but your 60' was awful no offense. A 'decent' 60' of 1.9 with good shifting should have gotten you a mid 12 run. As mentioned 111 mph is a bit off for a near stock 02-04z. 114-115 is more average. My best run stock with just the zip tie filter mod was 12.4 @114 1.9 60', that was on just 3 passes ever in the car. With the VR, LT's and tune ran 11.96 @119 1.87 60. Both runs were on 295/18 NT05's. They are an excellent street/track tire for the money imo. Probably not the best choice for a daily, great for a weekend car.


.

racebum

keep troubleshooting or take it to tom wong. the oe plug is now the delco 41-110. if you have a bad one that could do it, bad wire could do it. tom can check knock counts and pinpoint. will cost you shop time but it could be a time saver

wong's performance 360 695 9433

Potent68

Thanks racebum!

Last night I swapped the original 15+ year old, .060" gap, stock spark plugs with the new 41-110 iridiums pre-gapped at 0.40".

The car definitely feels noticeably better throughout the entire RPM range and that weird hesitation/missing feeling is pretty much gone. I say pretty much gone because I feel like the PCM has been learning the changes from the air cleaner assembly to the new plugs and it's been improving every time I drive it. I'm not sure how soon I'll be able to get back to the track with all the rain in the forecast but either way, I'm glad it feels so much better now.

racebum

unhooking the ground resets the fuel trims. pull the ground off the battery and start from zero.

.060 gap will do it, lucky you didn't waste a coil. the GF has a mercedes with 105k on it, OE plugs, finally took out a coil. i have harped to change those for a year or more. coil died. she limped it home on 5cyl. gap was about .065. new plugs and a new coil went in, runs great.

AmbulanceDriver

Glad your issues were fixed! I have ghost cels now. Same codes just randomly turn on now. Been a while day without them. Fingers crossed! Cheers!

Potent68

I think the stock gap from the factory was .055". I can't believe how much better and smoother the car feels even driving mellow. These cars are so much fun.