[Snowblind]

Anyone growing up in the 80's and listening to the band Foreigner knows that this is a title to one of their songs, I thought it may be appropriate for this thread.

I have attached the speed in gears chart which most of you have already seen by now, this chart and thread are specific to the A8 guys only (sorry M6 readers) because the gearing and axle ratio is different in the manual trans. This chart and topic has 1/8 and 1/4 mile implications so it is two-fold but we will address the 1/4 mile specifically. If you look at the bottom of the chart you will see that 114 mph is the top speed in 4th gear, no getting around it, at 6500 rpm the ECU cuts power to protect your motor.

I have attached my time slips from last week and I got in 8 solid passes. I have plenty of seat time and now my routine does not change, all passes are made the same way with one exception in these cases...I manually held fourth gear through the traps on my last 5 passes. Now, my car consistently shifts at 6200 rpm on the 2-3, 3-4, 4-5 and it was shifting just before the finish on each pass I made this whole summer. I was happy with my times but I wanted to see what running it out would do.

If you have studied the chart you will say, hey idiot, you can't run it out with a ceiling of 114 in 4th and you would be correct, however, I run a 305/35/20 which gives me a 28.7 height (27.5 stock) and a circumference of 90.1 (86.6 stock). I punched in the numbers and came up with a 119 mph limit in 4th. "Balls to Wall" I said and after my 3 passes of the car shifting itself, I held it in gear so let's check out the slips.





As you can see, my ET lowered and my mph increased by holding onto 4th through the traps and not letting the car shift at the line made me quicker and faster.

I will readily admit that my car took a nosedive every time I hit the line on the rev limiter and I was just wishing to get to it before it fell on its face. If you have been following closely, you will be asking me how I got to 120.9 on my last pass then...well...let's just say I tripped just before the finish and momentum carried me over...lol.

In summary, it is my opinion that if you research your tire size and find out what your speed limit is vs. what you are trapping now...you may be able to run it out and squeeze out that little bit more. It seems that even though I am well past my power peak, it is still quicker than a shift at the end.

1/8 mile implication; my top speed in 3rd gear would come out to 96 mph.

Side note; a tire size calculator may be different than the manufacturer specs so be sure to double check your size. ie....MT lists my tire height at 28.7 but the calculator shows 28.4 so I went with the MT math to figure my speed in gears.

P.S. side note; if you already have your tires and are second guessing yourself about your choice, don't, a smaller circumference tire will in theory net you a quicker 60' time than a taller tire, but if you haven't made the leap yet....and you don't plan on extensive mods in the future, then this info should give you food for thought. Once you up the power beyond this ET point then this avenue will no longer provide a benefit.

[ULTRAZLS1]

I held 4th as well. My tires are shorter than yours . 27.8-28.0 depending on calc or manufacturer. My 116.5 run I hit the limiter right at the line.

I went faster holding 4th as well.

I'm going to try short shifting into 5th next if my traps get too high with better DA. Motor makes great torque on the midrange might workout.

[jdasnt3]

Nice info! I'm using the same tire size you are. Looking forward to trying this trick.

[wnta1ss]

Snowblind, were you in 'D' until it went into 4th gear, then slid the lever over to the left so it would not upshift?

[Snowblind]

Originally Posted by wnta1ss

Snowblind, were you in 'D' until it went into 4th gear, then slid the lever over to the left so it would not upshift?

Yes, it's a long gear so at any point just shift it over to manual.

[laynlo15]

I did notice on my last passes it was shifting into 5th probably at about 1200 ft. Now mine does trap higher then most cars if you look at my last pass when I trapped at 118.60 and that was in 5th gear. We used to do this with our g8's before I went supercharged. With my taller 28" tall slicks holding it in 4th would probably make my car trap close to 121 looking at what your car picked up. I want to try this and I hadn't really watched the tach thru the traps. Good thinking snowblind and thanks for sharing.

[JFM-jr]

Your trap speed is a calculated number that is the average speed over the last 66 feet of the 1320. It can differ from what a GPS would tell you. I have no idea how far apart the figures actually are but the chart you show would be based on GPS figures. When you are this far down the track trap speed is effected alot more than ET. You could lift at the 1260 mark and still run an 11.85@109 for instance. The only way to know for sure is for everyone to share their findings like you have. Now people know with your tire size how far out 4th can be held wich is great.

[laynlo15]

It may not work with the short tire, but with mine being 28" tall slick and it growing a little on the top end it will work out on my car.

[hotlap]

Interesting info and great runs. Are you still DR only?

[Snowblind]

Originally Posted by jdasnt3

Nice info! I'm using the same tire size you are. Looking forward to trying this trick.

I'll be interested to see how it works for someone else with a 305/35/20, good luck.

Originally Posted by hotlap

Interesting info and great runs. Are you still DR only?

I am DR and skinny now, Roto CAI, seats out and Vitesse (mod?). No tune and all 4 cats still on.

[ULTRAZLS1]

Which setting at the track for the vitesse?

[mcsoul]

Somewhere I read that the Air Raid intake manifold lets you bump your redline a bit. Between something like that and the tune itself, you should be flying.

[JFM-jr]

Originally Posted by Snowblind

I'll be interested to see how it works for someone else with a 305/35/20, good luck.



I am DR and skinny now, Roto CAI, seats out and Vitesse (mod?). No tune and all 4 cats still on.

Race weight?

[hotlap]

Originally Posted by Snowblind

I am DR and skinny now, Roto CAI, seats out and Vitesse (mod?). No tune and all 4 cats still on.

The Vitesse isn't a power adder so I'd say not a mod. Some would say the same about the CAI. Tires and weight reduction are your biggest gain IMO.

Good job.