This past Friday I was planning to go to MIR but went to Capitol Raceway instead because the track was not crowded and it is closer to my home. The air temp. didn't drop as low as what was forecasted. The air temp. got down to 68F for my last run but I did not beat my best ET of 13.1 seconds. The track just did not hook and it was humid (80-85%). Here's a summary of my stats:
13.4@105.04 73F
13.3@105.81 72F
13.7@106.66 72F
13.8@105.99 70F
13.2@107.09 69F
13.2@106.76 68F
13.5@106.34 68F

That's the first time I've reached 107 mph in the 1/4. I've never gotten to race that many times in one night either. Definitely got my $20 worth.

 

107 mph? See what opening up the exhaust did? You gained 2 mph over stock despite losing 1/2 second due to high humidity...oh well? What wasn the temp. of the intercoolers? Was the motor hot before the runs? Ok, now it's time for the "Mafioso" air intake elbow and 3 lb. pulley, then hard re-set. You'll gain the "Off the line grunt" to overcome the disadvantage of the tall 2.88:1 rear-end cogs, and achieve the sub 13 second 1/4 mile that eludes you. I have a straight stretch of road that enabled me to measure out a 1/4 mile, and I use this every now and then to see what she'll do. A few nights ago in 45 degree outdoor temperature with very low humidy, she clicked off a 110 mph 1/4 according to the stock speedo. What a rush! IMO, as boost is increased the 2.88's run in our favor, albeit an LSD would still be nice (procured for $$$$). First gear is a stump pulling 4:1. Coupled with 16+ lbs. boost, one would easily roast the tires with 3.45 cogs. 2.88's allow less spin when launching under high boost = lower E.T. Must be nice to have a track nearby. The nearest to me is over an hour away. Keep up the good work STRacer.

 

Very nice! What tires and pressures did you run?

 

Thanks for the input and questions guys...

bfsgross,
I am not sure of the intercooler temps but I had ice cooling things down for all but the first run when the motor was warm, but not hot. As for the Mafioso air intake, it likely works and has a great high-tech and quality appearance but I have looked but not found dyno runs or 1/4 mile time slips showing a the amount of power increase. It sure does sound great though! My next mod will likely be the smaller sc pulley.

Michael Star,
My tires are Continental Extreme Contact DW 245/40/18 Front, 285/35/18 Rear. All tires are kept at 38 lbs. during normal street driving. The rear tire pressures are dropped when I go to the track and the front tires are kept at 38 PSI:

Sec @ MPH Temp - - - Rear PSI
13.4@105.04 73F - - - 30d 25p
13.3@105.81 72F - - - 30d 25p
13.7@106.66 72F - - - 30d 25p
13.8@105.99 70F - - - 25d 22p
13.2@107.09 69F - - - 25d 22p
13.2@106.76 68F - - - 25d 22p
13.5@106.34 68F - - - 25d 22p
notes:
XXd = driver's side and XXp = passenger's side
passenger side has lower PSIs since it has a tendency to spin more easily than the driver's side

Launching our cars with an open differential (A.K.A. Peg Leg)
Most 1/4 mile tracks allow room to drive around the water box for vehicles who you do not have slicks. For some unknown reason they forced all drivers to drive through the water box on this particular night. This caused my 60' times and elapse times (ETs) to be all over the place. Whenever possible I will go around the water and just spin/chirp the rear tires for just over a second to remove all debris. Before staging, if I spin much longer than a second it has always been counter productive. A big burnout with most street tires causes them to become too hot and they "glaze". Glazing of your street tires will provide you with a worse launch than if you did no burnout whatsoever. I've raced this car many times over the last few years and most every 60' time this summer has been at or below 2.0X seconds.

Reasons why to go around the water box with street tires...
A) Your front tire treads will hold water and make a perfect trail of water for your rear tires follow and spin on when you launch.
B) As you perform a burnout the water held in your rear tire treads is spun up inside your wheel well. Then, as you sit waiting at the staging light, the water drips down around and on top of your tires.

 

I've got those exact tires (although in the stock rear width) and I love them. I will try to get to the track this weekend and see what I can lay down. Also, that was a great tip about the different pressures between driver and passenger. I never would have though about that. One thing I was thinking about is disconnecting the front sway bar to help weight transfer that I might try the next time out.

 

1320racer, perhaps you can be the first to dyno/track test the "Mafioso" air intake elbow? Prior to your track experience, did you perform a hard re-set of the ECU then teach her to blaze? I'm itching for your opinion after the 3 lb. pulley install. I know you'll be surprised with your cats larger *****. Thanks 2x for your tire pressure and "Avoid the water box" tips.

 

https://www.jaguarforums.com/forum/s...t-43896/page6/

Post number 110 is where Mafioso posted his dyno findings from the intake. This is when he had the cat issues. If it doesnt cost me much for my hood and front bumper repaint I found a dyno near me but I dont know what they charge are yet. I may get some numbers with and without.

 

Do it!!! You wont regret it. I gained more then a tenth on my truck the first time I did this, and all at the launch. The weight transfer happens much quicker, and my 60ft time went from a 1.89 best with sway bar conected to a 1.75 best disconected, on street tires!

I'm sure the STR will like it too. Being a peg legger or a one wheel wonder I'[m sure any bit will help.

 

for you guys running those continental dw's how do they act in the cold weather? i live in pa and my str is kept outside. i dont use it in the rain or snow, but i do have to move it to shovel driveway from snow... i have nexen n7000 now which is all season but i am looking for a better responsive driving tire... i narrowed it to the dw's and hankook ventus. all input welcomed

 

They seemed to handle fine in the cold weather. I put mine on when it was still pretty cold out (for here at least) and they didn't give me an issue until I had to drive it one day in the snow. They didn't have traction to start or stop the car, but I think that is all summer high performance tires. I too narrowed it down to the DWs or the Ventus, but decided to go with the contis after reading lots of reviews that the v12s became hard and noisy after 12k miles. I couldn't be happier with the DWs. I am trying to convince my gf to get a set for her Mustang.

 

I have performed and logged the hard ECU reset without any noticeable performance difference. This may be because I drive aggressively most all the time and the ECU never learns any bad habits. My ECU resets were done before racing but after driving aggressively with "S" button ON for:

1. ~60 miles (test target of 50 miles)
2. ~90 miles (test target of 75 miles)
3. ~120 miles (test target of 100 miles)
4. not performed (test target of 150 miles)
5. not performed (test target of 200 miles)
6. not performed (test target of 250 miles)
7. ~340 miles (test target of 300 miles)

I remember recently reading on this forum an attachment (or link maybe) that suggested our transmissions not be put into "S" mode and driven hard for at least 300 miles after an ECU reset. What do our forum techs think?



carlorner,
You can't have the best of everything in one tire. The Continental Extreme Contact DW tires are okay for cool or cold weather here in Maryland but are worthless in any type of snow. The tread design doesn't clear itself of snow and no traction is provided for turning, starting or stopping. I still use them in snow but they are pretty bad.

Last Friday at the track I saw two 1999 to 200X Camaros running them. Like me, they said they didn't get them for the track, they got them because they are quiet and last.

 

I wouldn't worry about the S button. You're not after soft shifts when at the strip!

Also, I reckon the ZF has already decided how to shift and you need a dealer tool to clear its learned values.

If you do a PCM reset you'll also reset all its learned values to defaults. Possibly some are then values you don't want.

E.g. some cars (Ford at least) would start with a default BARO (barometric pressure) which if wrong will negatively affect fuelling. I don't think this affects the STR as it has an internal BARO. I've no idea what it defaults to after a reset (the right reading, I hope).

 

The ltft values will be gone after an ecu reset. These are learned during normal driving in closed loop and are used to get ideal values again for once you are in open loop (WOT). This process is needed as sensors (ie MAF)/injectors etc over time could be off. The ltft will be used to calculate the fueling under open loop, where the ECU has only the maf input (one of those sensors that could be off).
So it will be a gamble of what the a/f mixture will be if you reset the ECU, it can either be leaner or richer for a while, all pending on how well the mentioned sensors/injectors where working in the first place. For example, my car got much leaner when I resetted the ECU before a dyno run, so can’t recommend this, it’s like Russian roulette.

 

Pay attention to avos, guys!

On high-performance PCMs, such as Densos, there are commonly MULTIPLE learned values per major variable (such as the LTFT values). These are learned for multiple conditions, such as various speeds and/or throttle values. All the values for all the sets of conditions are cleared when the PCM is reset (battery disconnected) and then defaulted and subsequently relearned.

I don't know of any way to read out the many values to see how far from default they've moved
Pity, as they could easily point towards a component that ought to be cleaned/changed.
(Granted, you'll get a DTC if needs be.)

I'd not thought of it as Russian roulette, but I suppose it is!