RS4 60-90 MPH test-to shift or not to shift?

B6/7 S4/RS4
#1

I have tested this a bunch of times, but recently did so on a hot night so I’ll use those numbers since they’re freshest in my head. I wanted to figure out what the best approach was. The RS4 gearing is unlike the other S cars out there. 2nd gear revs out to 70 mph. 3rd hits 101 mph or so.

So, when doing a 60-90 test in the RS4, you have two options

  1. start in 3rd, rev it out, no shifting
  2. start in 2nd, rev it out to the top, shift into 3rd, rev it out

Not that the 60-90 metric is one that anyone gives a shit about but if you’re doing a highway pull with a friend from 50 or 60 mph up to whatever speed you like, it’s valuable information to know what gear to start in. I did some pulls with a member here in his 335i a while back, and we started at about 55 mph. When I did so in 3rd, the car just felt like it was laggy up until it got into the big RPMs. When I started in 2nd, it jumped hard right away thanks to the RPMs being up, but I had to throw an extra gear shift in there. I wondered if the shifting ate up the improved acceleration?

In option 1 you will be going from 60-90 in third a.k.a. around 4800 RPM to just before redline. If you are doing a pull from 50-?? MPH, you are starting in third at only 4000 RPM. This is where the car seems to lag a bit. from 5500 and up the car feels a lot stronger.

When I did 60-90 rips just in 3rd gear, the pbox spit out 4.6 to 4.7 seconds. Mostly 4.6.

When I repeated the test, but started in 2nd gear the outcome was a little different. 60MPH in second gear = around 7000 RPM so this sounds dubious at best. You have to remember that you’re not starting the test (or pulls) at 60…probably 50 mph and rolling through. When you start at 50 MPH you’re ‘only’ at 5800 RPM so that leaves you with 2400 RPM of headroom before you need to shift into 3rd.

When I did 60-90 rips in 2nd, shifting into 3rd, the pbox said 4.5 seconds 4 out of 4 times I tried it. Further I did the 2-3 test AFTER the 3rd alone testing…so the car was PLENTY hot by the time I tried the 2-3 which can only hurt the 2-3 results. Despite that they were better.

Now I imagine you have to be a pretty quick shifter for this to make sense…and you have to be a big geek to care about that tenth etc. but that can be a car length in a pull. Anyway, thought I’d share it.

http://i50.tinypic.com/hv1ou8.jpg

#2

When I was doing the 60-130 stuff I too was starting in 2nd at about 45 and shifting my way through third into 4th. I felt even with the one extra gear change the times were improved. Turns out 137 on the speedo is not even 130 on PBox so my times never registered for the 60-130…

#3

speedo 140 is retarded. Useless test.

What tires do you have on your car? Smaller than stock maybe? 275.30.19 = 0.5" smaller than stock height = 2% off

#4

Stock size tires. Speedo is just off in the higher mph range. I have tested it against three other gps units simutaneously.

Examples I tested: 100MPH indicated is actually 93.4MPH GPS in my car. ~7MPH is a larger than expected discrepancy imo for 100MPH. It gets slightly bigger as you increase speed. 120 indicated was 112.2mph via GPS.

#5

I have approximately the same amount of speedo error. Although mine seems almost constant around 6mph faster than actual SOG according to my Garmin.

Interesting that 2nd/3rd is faster even with the gear change. I’m guessing short throw shifter would help too?

#6

In theory it would

I drove Axel’s supercharged B7 S4 Avant last night. It had the full JHM treatment with respect to the transmission…and it felt awesome. Clutch/Flywheel/shifter/trio

The shifts were so short…it was fun.

#7

Funny, revisiting this thread

60-90 mph stock RS4 in the summer 4.5-4.6 seconds from above

I have since done loads more tests

60-90 mph stock RS4 in good DA (0 feet) 4.0-4.2 seconds
60-90 mph stock RS4 in EPIC DA (-2000 feet) 3.9 seconds
60-90 mph full JHM catted exhaust in good DA 3.9 seconds
60-90 mph full JHM catted exhaust in EPIC DA 3.76 seconds

This week I gathered some data on supercharged RS4s (JHM stage 1 and 2). Here’s a useless piece of data that shows how an RS4 does in the worst possible conditions

60-90 mph JHM stage 1 6 psi, no intercooler, JHM downpipes, 245lb driver, 265 lb passenger, 40 lbs luggage, +200 feet DA 3.41 seconds

Pretty interesting to compare these times. Take out the 300 lbs and run that car in -2000 feet of density and it will be veeeery interesting.

I’ve also got data on the stage 2+ car in good DA, but I was sworn to secrecy until they finalise everything with the kit. It was significantly faster is all I will say lol.

#8

Very interesting indeed! Thanks for sharing this info.

#9

I recently had a lightbulb moment that explained why in a STOCK RS4 it makes more sense to start in 2nd if you’re a quick shifter

the stock tune has a throttle limit (it’s spurred by a torque measurement that when exceeded, the car holds itself back). Stock tune limits throttle in decent DA to 52% up until around 5500 RPM where it opens right up to 100%.

If you start a 60-90 in 3rd gear, you hit 60mph at 4800 RPM…so the throttle is limited as is your power. Once you hit 5500 it opens up but it has held you back. How much ? Not enough to make it worthwhile to start in 2nd if you’re a slow shifter…but it is enough to make it worthwhile to start in 2nd if you are a fast shifter. If you start the pull in 2nd gear you’re going to hit 60mph around 6900 RPM, leaving you around 1100-1200 RPM in the gear. Certianly worthwhile. You’re also closer to peak performance up top in the gears, so that helps all around.

For example when we tested the JHM supercharged cars, they were better starting in 3rd because the JHM tune elimimnates these restrictions and lets the car make full power in each gear at all RPMs. The drivers were VERY fast shifters. I would say maybe the fastest shifters driving Audis on earth. They still found it was better to start in 3rd. Only by about a tenth, but still faster.

#10

Funny, revisiting this thread

60-90 mph stock RS4 in the summer 4.5-4.6 seconds from above

I have since done loads more tests

60-90 mph stock RS4 in good DA (0 feet) 4.0-4.2 seconds
60-90 mph stock RS4 in EPIC DA (-2000 feet) 3.9 seconds
60-90 mph full JHM catted exhaust in good DA 3.9 seconds
60-90 mph full JHM catted exhaust in EPIC DA 3.76 seconds

This week I gathered some data on supercharged RS4s (JHM stage 1 and 2). Here’s a useless piece of data that shows how an RS4 does in the worst possible conditions

60-90 mph JHM stage 1 6 psi, no intercooler, JHM downpipes, 245lb driver, 265 lb passenger, 40 lbs luggage, +200 feet DA 3.41 seconds

Pretty interesting to compare these times. Take out the 300 lbs and run that car in -2000 feet of density and it will be veeeery interesting.

I’ve also got data on the stage 2+ car in good DA, but I was sworn to secrecy until they finalise everything with the kit. It was significantly faster is all I will say lol.

#11

Very interesting indeed! Thanks for sharing this info.

#12

I recently had a lightbulb moment that explained why in a STOCK RS4 it makes more sense to start in 2nd if you’re a quick shifter

the stock tune has a throttle limit (it’s spurred by a torque measurement that when exceeded, the car holds itself back). Stock tune limits throttle in decent DA to 52% up until around 5500 RPM where it opens right up to 100%.

If you start a 60-90 in 3rd gear, you hit 60mph at 4800 RPM…so the throttle is limited as is your power. Once you hit 5500 it opens up but it has held you back. How much ? Not enough to make it worthwhile to start in 2nd if you’re a slow shifter…but it is enough to make it worthwhile to start in 2nd if you are a fast shifter. If you start the pull in 2nd gear you’re going to hit 60mph around 6900 RPM, leaving you around 1100-1200 RPM in the gear. Certianly worthwhile. You’re also closer to peak performance up top in the gears, so that helps all around.

For example when we tested the JHM supercharged cars, they were better starting in 3rd because the JHM tune elimimnates these restrictions and lets the car make full power in each gear at all RPMs. The drivers were VERY fast shifters. I would say maybe the fastest shifters driving Audis on earth. They still found it was better to start in 3rd. Only by about a tenth, but still faster.

#13

Good info in this thread. *sub’d to read on my lunch break

#14

Good info in this thread. *sub’d to read on my lunch break

#15

Is under a 2.5 good?

#16

under 2.5 is great.

I have only seen one other B7 RS4 that is faster than 2.50. Wonder if you guys are second fastest again :slight_smile:

What was your elevation change?

p.s. did you just leave it in 3rd? We found that was fastest on JHM supercharged cars. On stock tuned cars, starting in 2nd keeps you in the high RPMs with no throttle restriction. If you did it in 2nd and shifted, try it without a shift.

#17

oh and now you have to post the chart since you talked about it and you’re a shop

sounds like you either had epic density altitude or you changed something on your test RS4 because I don’t think it was able to go sub 2.50 2 months ago when you hit the strip. Maybe you can correct me or confirm that. You were trapping barely 130 on race etc back then.

#18

Is under a 2.5 good?

#19

under 2.5 is great.

I have only seen one other B7 RS4 that is faster than 2.50. Wonder if you guys are second fastest again :slight_smile:

What was your elevation change?

p.s. did you just leave it in 3rd? We found that was fastest on JHM supercharged cars. On stock tuned cars, starting in 2nd keeps you in the high RPMs with no throttle restriction. If you did it in 2nd and shifted, try it without a shift.

#20

oh and now you have to post the chart since you talked about it and you’re a shop

sounds like you either had epic density altitude or you changed something on your test RS4 because I don’t think it was able to go sub 2.50 2 months ago when you hit the strip. Maybe you can correct me or confirm that. You were trapping barely 130 on race etc back then.