All passes were at 15 psi. Complete street car. Full weight, full interior, drove to the track, off the road and into the staging lanes. 93 octane pump gas. No meth/water/alcohol injection, no E85. 255/45/17's in front, 275/45/17 DR's out back. 3.55 gears, stock T56, SPEC stage 4 clutch. Full exhuast(Borla cat back), no dumps.

Environment:
Heavy storms all around but not raining in our immediate area at the time I arrived at the track.
Barometric pressure: 29.54
Humidity: 100%
Air temp underhood: 108degres.
Outside temp: 72degrees

The weather forecast strong thunderstorms so I rushed to the track with my tools in the trunk and a full 13 gallons of gas in the tank. The track is 7'ish miles from my house (<Napoleon Dynamite voice>"Luckee.."). There weren't too many cars or bikes there. Perhaps 50 or 60 in total? Fearing the rain could start at any moment and wanting to get at least one time trial, I didn't take my tools or the tub to hold them out of the car. I got out to check the air pressure in my Nitto DR's (275/45/17) and, at 40, I took them down to about 28 psi. Right then, a few sprinkles came down and I cursed, but then it stopped.

In the past, I've just dumped the clutch like I used to on M/T ET streets but these DR's don't like that and either spin or bog. I decided to 'drive' this time and feed the clutch out while keeping the RPM's up. Viola!! I got my first sub 2.0 (1.909) sixty foot since I put on the Turbo! But... shifted to second and it spun so hard, it made me lose my concentration so I tried to clumsily shift to 3rd but went into 5th, let out the clutch, realized my mistake, re-clutched and shifted to 3rd and got the rest of the race right.
I logged the passes. This pass had a lot of knock retard going on.

Results:
Left the line at 3,825 rpm.
Reaction time: .35377
sixty foot...: 1.909
330 foot.....: 5.309
660 foot.....: 8.37053
1/8th MPH....: 87.28
1000 foot ...: 10.696
1/4 mile ET..: 12.57353
1/4 mile MPH.: 121.89

The car felt fine on the way back. Running nice and cool, exhaust burbling. Oil pressure and all other gauges showing normal.

Went back and got in line(hot lapping) and talked to a nice young gent with a new blue GT500. We spoke a bit and he said he was spinning quite a bit tonight. He was there from Kingston area and had several buds with turbo Subarus and a Cobalt SS. Nice guys.

Time for the second pass. As I cleaned off the tires for the next pass, a check engine light came on. I made the pass anyway, deciding to check what it was after the pass since the car felt fine and all gauges were showing the normal readings. Rats... I let out the clutch too quick and I got my normal crap sixty foot, but a better MPH. My best to date with the current setup...

Results:
Left the line at 3,700 rpm.
Reaction time: .33675
sixty foot...: 2.107
330 foot.....: 5.553
660 foot.....: 8.08423
1/8th MPH....: 98.20
1000 foot ...: 10.212
1/4 mile ET..: 11.96798
1/4 mile MPH.: 128.96
Oddly, this pass, though still getting knock retard, only got it in 4th above 4,800 rpms.

Once again, I hotlapped it and went back in line. This time the GT500 guy wanted to race heads up. I said sure. Meanwhile, I checked the DTC and it said it was a low MAP reading. Odd... never had one of those before. I got out, checked the connectors and all and everything seemed to be in place. I cleared the DTC and started the car. No error right away. So the GT500 and myself line up and warm up the tires. Again comes the check engine light as I finish the burn out of the tires. We stage and the lights come down.

Results(GT500):
Reaction time: .53343
sixty foot...: 2.324
330 foot.....: 5.764
660 foot.....: 8.38338
1/8th MPH....: 95.04
1000 foot ...: 10.591
1/4 mile ET..: 12.45491
1/4 mile MPH.: 121.01

Results(ME):
Left the line at 4,775 rpm.
Reaction time: .34377
sixty foot...: 2.090
330 foot.....: 5.338
660 foot.....: 7.95996
1/8th MPH....: 98.94
1000 foot ...: 0.0000 (??!)
1/4 mile ET..: 11.95621
1/4 mile MPH.: 126.03

By the time I got back to the staging lane, a huge crack of lightning spanked the trees not to far away and the announcer told everyone to get out of the stands, "Show's over!"

I had a good time! Keven and Adam Martin from Twisted Synergy were there and they stopped by to say hello. It was great to see him again.

On the way home, though the gauges read normal, the car was running a tad lean and felt a bit weak. I gave her some gas and watched the boost gauge. Hmm... only gets about 2 or 3 psi. Sounds like a coupler has came nearly off or I have a split in one of them. I'll check tomorrow.

 

Good stuff! Get some real tires and put them in the backseat so you can swap them at the track. Heavy+power makes driving on a Nitto a real chore. Next time out will be a lot better with less weight. Goodluck.

 

Got up this morning and was reviewing my data logs from the 3 passes. I'd mentioned above that I got a DTC for "Low Map Reading". On the first pass, the MAP KPA was 44 at idle. At WOT, it was as high as 104 all the way from 1st gear till about the middle of 3rd gear, then it plummeted to 89, then down to as low as 11, all still at WOT, with the MAF max'd out at 471 and the RPM's at 6,000.

Reviewing the 2nd pass, MAP was ONLY 10 or 11 at WOT and idle. Going out here in a moment to see if the seal around the MAP crapped out. If that's not it, I'll look at the MAP sensor itself.

 

Nice.
Pics of the setup.?

 

Found it. The middle wire/pin in the MAP connector had backed out.


I plugged it back in and reinstalled it. Just about to go for a test drive.

 

Sounds like a low 10 second car when you get things sorted. I am surprised you are still using worm gear hose clamps. If it works, don't fix it.

 

I thought I had to for those oval shapes. Believe me, those ratbag clamps have popped off a few times. Occasionally at embarrassing times. Do you know what T-Bolt clamp options I have for those ovalized parts?

I just got back from a test drive (14 psi). I data logged it and found that the MAP KPA was pegged at 104 the whole time I was at WOT (100% TPS). Perfect. I had wondered why in all my past data logs (going back a month or two) the MAP KPA during WOT would vascillate between 104 and 8x and all points in-between. I can now suggest that the connector pin was making erratic contact. That probably also explains why my timing at WOT would go from the desired 2x advance to 41 (instantly introducing a ton of knock retard) for just a nanosecond, then go back to 2x advance.
Thanks,
Dave

 

Good MPH, just need to get tracking and get out of the hole.

 

Thanks I have a built TH350 for it but I'm waiting on getting my Vigilante TC restalled from 2800 to 4000rpm. That should help. I have a two step and I'm contemplating getting a Transbrake.

 

There is a LT1 car in the latest GM High Tech Performance magazine using T-bolt clamps. I am guessing all you need to do is press down on them to make them more of an oval.

 

i use a 4" t bold clamp on the throttle body it oval out as you tighten it. you can use any t bolt clamp on anything oval or round the mafs are 3.5" and i would but them off ebay there cheap and i never had one issue ever with them and get the one with nuts not wing nuts

 

Nah.. It couldn't be that. That makes too much sense Thanks for the tip! I'll get a couple and try that out!

 

Get some ET drags and let it eat!

 

10 bolt still?

i have same kinda set up and im worried ill blow the diff out of it on slicks

 

My 10 bolt lasted thru several 11 second passes via nitrous on M/T ET streets and Hoosier 28" drag slicks as well as several pairs of DR (Nitto and BF Goodrich) but it finally broke in 2003 at the MTI Spring Break shootout in the semi final. At that time, I opted for my current Ford 8.8/GM 10 bolt hybrid differential. The center section and 10" of the legs are Ford 8.8 while the rest of the legs are from my stock 10 bolt so the calipers, etc will bolt on. The axles are by Strange. I've had both 4.10's and the current 3.55's in there and it's taken everything I can throw at it. At the time, I got it for $1,400 If I recall correctly. The guy that was creating them quit methinks. Some of the welding for the torque arm mount was breaking for some of the customers. I hear it can be a challenge to get mild steel to weld to cast iron. The fabricator was called Extreme Chassis at the time.

 

Dave, like I mentioned on cz28:

I knew something wasnt right... even your last track outing when you said you trapped 98mph in the 1/8th.

With your old ported stockers and the 4.10's you did 108mph in the 1/8th a couple years ago. With the new LE TFS heads and 3.55's.... I was expecting 135-140mph traps.

Oh, and a 4" Tbolt clamp fits our TB's. I have several lying around... shoot me your addy and I will drop one in the mail.

Jon