jxhunte

C6, LS2, E85/Flex Fuel, PRC heads, 227/234/114 cam, Johnson 2116 LSR Lifters, 1.7 Rockers, PNR 7.5 gal Ice Tank, E-Force supercharger, 2.75" pulley, Headers, exhaust, etc. At the track, tuning for the new cam and heads, recording Burst Knock Retard for the first time, I was seeing 12 degrees of retard at WOT, Launch. I had never before messed with Burst Knock Retard but seeing the amount of timing being pulled at Launch, I decided to zero out the Burst Knock table and the result was no timing pulled at launch, no recorded knock at WOT, followed by wheel spin or for the first time I could not hook-up at launch. My MT ET drag radials (295/45R17) have served me well in the past, they are a few years old, but I cannot get them to hook now, after removing BK retard. I tried lowering tire pressure which helped some but because of the age of my Drag Radials, my plan is to replace them. The 295/45R17 is no longer offered so my next choice as recommended by several enthusiasts is the MT ET Street SS 275/40R17. Anyone know of a better option I should consider? I drive the car to the track and back or an approximately 70 mile round trip via I70 from Central City, CO to Bandimere Speedway.

Dano523

To stick, you can either use Burst knock retard, or going into Torque management instead.

Of the two, if its just the launch you are having problems with, not down the track with the tires breaking free there, then better to just retard timing at the launch, since TM would be limiting all the way down the strip isntead.

If running a A6, then can play with the pressure amounts before the Torque convertor does a full lock up, to keep the tires stuck on the launch out of the hole.

Bottom line, your throwing too much power at the amount of grip the tires have, and its the reason that they are breaking free. If you can not solve the problem with your right foot to limit the amount of power to the ground to keep the tires from breaking freel, then it done electronically if your going to use the gas pedal like an on/off switch isntead.

Turbo6TA

I have used a set of 305/45 -17 drag radials mounted on 17x11 (+45mm offset) wheels on my GS ... they would be better at dealing with your HP level.

I think the 275/40 -17 is way too small for your car's HP

Here are the 305/45 -17 drag radials when I had them mounted on my GS:

subfloor@centurytrans

Plain and simple, you need better tires.

Drag radials have a fairly short life expectancy so it's absolutely no surprise they're not hooking and I think it's only a coincidence this happened after the tune change. You don't mention how many different runs you've tried after making the change but if its only one trip to the track with a few passes that may be too small a sample size to definitively blame it on that.

If it was actually because of the tune change it simply means you were already at the edge of how well the tires were able to hook. You don't need to put any TM back in the car or play around with lockup to hook properly as I have everything turned off and except for nights when the track is poorly prepped (or sometimes not at all) I hook extremely well and I'm probably making more power than you. The timeslip shown below was from the last race and in addition to the 1.357 60ft time being with a stock 2.56 differential, I even did a small wheelie on the launch.

If you have the option of changing the tires at the track then a 315/35/17 Hoosier drag radial will fix all your issues.