jhshnh

So my A4 car went 12.89 at 109 with stock converter and 2.73 gears in February. On street tires with 2.0 60'.

I bought some MT ET drag radials 255/50 R16 and put them on the stock snowflake rims... only mod since the February runs.

So last night at the same track I couldn't get out of the low 13s with slower 2.10-2.20 60s... Very little tire spin. My mph is still up there in the 108s. So my theory is I have too much tire for stock stall and 273s. Am I correct on this?

If my mph was slower I would think it's the car, but on the launch the car felt sluggish like the tires were creating too much rolling resistance.

madmike9396

iTrader: (29)

Yes same issue I ran into today.

zracer323

iTrader: (12)

Were you spinning before? If not, they will slow you down slightly. What was the DA when you ran this time compared to last? Could just be the weather.

transampetews6

iTrader: (31)

This exactly. get yourself a converter too. should really wake up you car.

jhshnh

The DA was 1500 feet and 84 degrees compared to February's runs at degrees and a negative DA. The mph was a little slower which I contribute to the DA and temperature.

Yes I was having to feather it off the line with the street tires. The dr's I could build it up and launch with little to no spinning. Which leads me to believe my lack of converter and gears is just bogging me down the first 100 feet. After it gets going the car moves like it always does.

01ssreda4

iTrader: (96)

Did the tire diameter go up? Ive always seen my car fluctuate a few tenths over the course of a night. Usually getting faster as the night goes on....

jhshnh

No. It stayed the same. I started at 30 psi. I kept dropping it and the car got slower. Bumped it back up and it got quicker. Didn't have enough air to get back to 33 psi. But the lower the tire pressure the slower the 60 foot.

krissoto

iTrader: (3)

If the car actually hooked that might have been why it slowed down. Might sound dumb but it happens. Might not have been up in the rpms high enough to get the car moving like you are use too. Tires might be done. There's alot of variables.

jhshnh

It definitely didn't get up in the rpm on the launch. Just kinda bogged. I'm saving for a built trans and 3800 stall. Not sure which brand yet, but it's high on my to do list.

Doug G

Spinning will skew the MPH higher since the motor gets into the better RPMs that the cam likes.
I got my best 60's flashing the converter from about 1000-1200 RPM Vs. trying to leave at 2000 RPM+
DA in February is going to be better than this time of the year most of the time.(do get that rare mineshaft air on occasion)

senicalj4579

iTrader: (41)

1500 da vs da in the negative says a lot.

When my car was bolt on only stock stall it went from 13.2 in 2200da to 12.6 in -1000da

Tuskyz28

Take the car back to the track and experiment with tire pressure. No 2 cars is a like and most cars respond differently with very little air pressure differences in the tire.

jhshnh

I'm going back ASAP. This time I won't build up I'll let the stall flash and I'll start my tires at 33 psi.

Kingc8r

iTrader: (21)

My car with a stock converter ran it's PB on stock tires. I slowed down with 555r's and Hoosiers. I even have the steeper 3.23s....I always ran my best time brake stalling my car to 900-1050 RPM then rolling into it

jhshnh

It's crazy how just different tires completely change the car. But a stall is coming soon. And gears.

BODUKE

The taller tires effected your et. It effects your gear size. Also you have to go down to 22 pounds of air.

Tuskyz28

Next time you buy try Hoosier tires. So much more of a stickier tire.....

T6Rocket

The higher DA was what changed the car the most. The tires just happened to be along for the ride.

Also, I would not run them on 33 psi, might get wheel hop. Set them on the typical 17 psi, but you could do a very short burnout.

Al

Bowtiedford

iTrader: (9)

my MT Dr's are set at 17psi to 20psi. and work great at that range. does sound like the car is creating a bog with those tires.

Doug G

18-20 psi with my 275/60/15 MT DR's