Drag Radials for the 135I

[ModlessG]

I just ordered the BFG Drag radials for my 135I. I have the 17" rims (205/50/17 run flats) so I ordered the 225/45/17 BFG tires from tire rack. What tire pressure should I run in these to race? I raced with the run craps and my 60' times averaged 2.55.Manual trans = no traction. any guess on the improvement with the drags?

[HIPSI]

All depends on track prep, how high you want launch etc... I'd start at 28-30lbs and adjust from there. The more air in the drags you can put w/o wheel spin will make for the best overall ET. I'd guess with an agressive launch a sub 2.0 60 ft is easily obtainable.

[Citizen Z]

You can hit sub 2 sec 60' with good launch technique on street tires. With your drag radials you should consistantly be sub 2.

[ModlessG]

I was thinking 2.0 a lot better than 2.5

[Citizen Z]

Originally Posted by ModlessG

I was thinking 2.0 a lot better than 2.5

If your 60' is 2.5 seconds, you need the driver mod, not new tires.

[ModlessG]

All I can say to that is you try launching with the 205 all seasons.

[Citizen Z]

Originally Posted by ModlessG

All I can say to that is you try launching with the 205 all seasons.

I have. 2.2 sec 60' is perfectly feasible. Try lowering the pressure to 25-28 cold PSI, 30ish PSI hot. What RPM do you launch at?

[WhiteSled]

I nailed a 1.76 with 275 bfg drags on friday. However they rub over bumps even with my rear fenders rolled. 4k pretty much step off the clutch, you hear a lil chirp and its time for 2nd gear. Amazing feeling lol

[ModlessG]

If I launch at any more than 3500 it just spins. I have tried to feather the clutch a bit. I have been short shifting 2nd gear at about 5700 rpm to reduce the wheel spin. Then shift @ 6000 for third.

[Citizen Z]

Originally Posted by ModlessG

If I launch at any more than 3500 it just spins. I have tried to feather the clutch a bit. I have been short shifting 2nd gear at about 5700 rpm to reduce the wheel spin. Then shift @ 6000 for third.

Launch low. Like, 1500 rpm low and you will be rewarded.

[SpeedballTrix]

Originally Posted by WhiteSled

I nailed a 1.76 with 275 bfg drags on friday. However they rub over bumps even with my rear fenders rolled. 4k pretty much step off the clutch, you hear a lil chirp and its time for 2nd gear. Amazing feeling lol

You launched at 4k? Wow.
But the 60' speak for itself. That's ballin.

What was your ET?

[WhiteSled]

my et was limp mode oncei hit 3rd gear.....i dont want to talk about it lol. 5.0 in the 330 7.8x in the 1/8th

[The HACK]

I suggest you read this guy's post CAREFULLY.

http://forums.bimmerforums.com/forum...89&postcount=1

Dude is one of the most respected drag racers on Bimmerforums, has been doing it for YEARS and knows his sh*t. He launches at 5,000+ RPM on drag radials at 16-18psi.

Those recommending higher tire pressure, all you're going to be doing is limiting your available traction and power on launch. You want to be able to maximize your available power and traction. So drop those PSI to 20 or less in the rear, bump the front up to 40, and let her rip in the sweet spot of the engine.

[WhiteSled]

which is not 5000 plus....i launch just under peak tq and then chrip/spin the tires and it grabs right around 4500, which is where my peak tq was made. There is no such thing as a Launch guide, every car is different every driver is different...we can make suggestions but you just have to go out there and do it yourself and find what works best without breaking something.

This is what i do.
2nd stage light, crank up the ebrake, put the car in 1st, let the clutch out till i feel the car move A TINY BIT to preload the suspension at idle. hold the clutch in that spot, rev it up to 4k...3rd yellow let go of the handbrake, floor the gas, quick release of the clutch. Sometimes if you do it to quick you have to pause your release ever so slightly or else you'll bog

[ModlessG]

I finally put the drag radials on the car. 225/45/17 I am running them through a few heat cycles before I go to the track on Wednesday night. The car already feels faster as the traction is way better than the stock 205/50/17 all season tires. I think that I will start off with 25 perhaps down to 21 psi and just go from there.

[The HACK]

Originally Posted by WhiteSled

which is not 5000 plus....i launch just under peak tq and then chrip/spin the tires and it grabs right around 4500, which is where my peak tq was made. There is no such thing as a Launch guide, every car is different every driver is different...we can make suggestions but you just have to go out there and do it yourself and find what works best without breaking something.

This is what i do.
2nd stage light, crank up the ebrake, put the car in 1st, let the clutch out till i feel the car move A TINY BIT to preload the suspension at idle. hold the clutch in that spot, rev it up to 4k...3rd yellow let go of the handbrake, floor the gas, quick release of the clutch. Sometimes if you do it to quick you have to pause your release ever so slightly or else you'll bog

There's a bit of misconception wrt torque vs. power. You want to launch at peak power, or at least, if you still have enough traction you want to launch at as high as you can get on the power graph, not the torque graph. Torque only tells you how much force is turning the engine. That same torque applied over the numbers of times engine is turning, is what power you can actually use. If your peak power happens at 5,000 RPM, you want to find that fine balance between available traction and when you'll hit peak power.

Torque as a number is meaningless in drag racing applications, it's that torque in combination with how many times it gets applied in a minute (RPM, hence HP) that will determine ultimately how fast you can launch a car.

Read the link I supplied. The guy has the fastest time I've ever seen on a STOCK E46 330i, by quite a large margin and the time slip to back it up.

[ModlessG]

It was a fun night of racing up at Bandimere Speedway the air density was 8300' with a nice 10 to 15 mph head wind. I got my 60' down to 2.08 really didn't want to run it too hard as I need to drive it today. 14.04 @ 100.26 mph was my best run. That corrects to about a 13.4 @ 103. I will go back when the weather conditions are better. The car rides noticeably better with the drag radials. I wonder how many miles they would go on the street? I had a friend there with his heavily modded Evo. He has run 12.99 in the past but last night was running 13.6. Just tough conditions

[Evo8MRto335I]

Originally Posted by ModlessG

I just ordered the BFG Drag radials for my 135I. I have the 17" rims (205/50/17 run flats) so I ordered the 225/45/17 BFG tires from tire rack. What tire pressure should I run in these to race? I raced with the run craps and my 60' times averaged 2.55.Manual trans = no traction. any guess on the improvement with the drags?

so you ordered 205 and 225?, that is smaller than stock. Why would you do that?