Login


12142013, 02:10 PM  #67  
Banned
0
Rep 47
Posts 
Quote:
Each consecutive gear would require an increase in power equal to the same percentage of difference between each gear ratio for that statement to hold any merit, and that doesn't even take into account any drag, which increases exponentially with speed. Last edited by <3VOM; 12142013 at 03:25 PM. 

Appreciate
0

12142013, 03:07 PM  #68  
2016 Track Days  3 Ridge 1:52:24Pacific 1:33:30
4539
Rep 18,029
Posts 
Quote:
__________________
02 Tiag e46 M36MTGC platesMCS c.o.GC barsGC race control armsGC bushingsBW eng. & tran. mountssubframe kitBW race shifterBW JaffsterEuro headerBW exhaustK&N c.a.i.Epic race tuneRouge pulleysSeibon CF hoodCSL bumperapr gt 250 & splitterST40XR2SS lineshalf cageRecaro profiProfi 2 harnessBMWpedalsBW studs 

Appreciate
1

12142013, 04:05 PM  #69  
Native Texan
500
Rep 3,322
Posts 
Quote:
Additionally, w/ w/m, you have to have a nozzle for each port, not just one. http://www.golfmk6.com/forums/showpo...9&postcount=49 Quote:
Last edited by whats77inaname; 12142013 at 04:17 PM. 

Appreciate
0

12142013, 05:17 PM  #71 
Lieutenant
17
Rep 473
Posts 
I used to spray 100% methanol on my MINI JCW(boy did that engine love meth) and after 25k miles, things still looked clean. I did get a walnut blasting done at 30k miles prior to installing a meth kit. No catch can but was meth tuned. That JCW had more torque than my current M3 too. Yikes.

Appreciate
0

12142013, 06:45 PM  #73  
Lieutenant
81
Rep 576
Posts 
Quote:
Of course, as you hold the gear and accelerate above 5500 revs, the acceleration will continuously tail off, for the same reason: constant power going through the drive train. 

Appreciate
0

12142013, 09:39 PM  #74 
Banned
0
Rep 47
Posts 
No. You're still wrong. Even taking out the wind resistance.
If you had one gear from zero to top speed, and made max power from 0rpm to redline, and redlined at top, and still ignored drag, that would be the only time the rate of acceleration would not change. Your rate of acceleration will decrease with every upshift, for reasons already explained above. 
Appreciate
0

12142013, 11:51 PM  #75  
Lieutenant
81
Rep 576
Posts 
Quote:
Anyhow, this has been discussed in a number of threads so let's not start another one even if we disagree on this.... 

Appreciate
0

12152013, 01:12 AM  #76  
Banned
33
Rep 1,017
Posts 
Quote:


Appreciate
0

12152013, 01:16 AM  #77  
Banned
33
Rep 1,017
Posts 
Quote:
Quote:


Appreciate
0

12152013, 01:23 AM  #78  
Native Texan
500
Rep 3,322
Posts 
Quote:


Appreciate
0

12152013, 01:34 AM  #79 
Banned
0
Rep 47
Posts 
Meth paired with two oil catch cans and 230000kms of direct injection, and my valves are spotless.
Power would have to increas by the same percentage each gear ratio differs, in order to maintain equal acceleration rate. Also, does the car run the same final drive on all forward gears? I doubt it. 
Appreciate
0

12152013, 01:51 AM  #80 
Brigadier General
107
Rep 3,414
Posts 

Appreciate
0

12152013, 11:46 AM  #81  
Lieutenant Colonel
62
Rep 1,987
Posts 
Quote:
In the extremely unusual case of this engine, shifting from one gear to another in the upper gears at 7300 gets you back to something over 5500 rpm, which is where the peak power range begins. Therefore, acceleration at that point will be the same as just before the shift. Yeah, I know it sounds weird, but think of it this way: The drop off in rpm is proportional to the change in gearing, so the drop in torque to the drive wheels will also drop  but the rise in engine torque at 5500 (compared to 7300) is exactly enough to offset the gearing change, given that engine power stays the same. Power equals torque times rpm over 5252. Bruce PS  You could in fact make the case that acceleration right after the shift point will actually increase in this case, since rotational inertia will be less in the higher gear. That has implications for shifting even a little earlier. This will be a very cool car coming out of corners and absolutely blasting down the straights. 

Appreciate
0

12152013, 12:14 PM  #82 
Banned
0
Rep 47
Posts 
Let's just say, you can accelerate from 60100mph in 3rd gear, and stay within the 55007300rpm powerband, now you shift from 3rd to 4th, and remain above 5500rpm, and accelerate from 100140mph. It WILL take longer to go from 100140mph than it did to go from 60100mph.
Both differences of 40mph. Both within the max power band. The only differences being gearing and elapsed time. Last edited by <3VOM; 12152013 at 12:19 PM. 
Appreciate
0

12152013, 02:44 PM  #83  
Lieutenant Colonel
62
Rep 1,987
Posts 
Quote:
Here's the shorthand deal: Speed eats power. It's as simple as that. Let's say you can attain a certain amount of acceleration at, say, 40 mph in first gear in the current car. Let's also say that 40 mph is at the power peak in first. Ignoring any changes in wind and rolling resistance, you will need exactly two and one half times the power to accelerate at that rate at 100 mph. In other words, your 414 HP M will need 1035 HP to pull as hard at 100 mph as it does at 40. Or conversely, it will pull only 40% as hard at 100 as it did at 40, assuming both speeds are at the power peak, and of course assuming no difference in wind and rolling resistance. The key point here is that at any given speed, horsepower governs acceleration, torque and gearing be damned, so the new car will accelerate just as hard after the shift as before, assuming the rpm differences stay between the 55007300 rpm window. Of course, right after that, acceleration will begin to taper off, because the speed is rising while power remains the same  and as I said, speed eats power  in a perfectly linear way. Bruce 

Appreciate
0

12152013, 02:54 PM  #84  
Native Texan
500
Rep 3,322
Posts 
Quote:
2) How many miles were on the car before you started using catch cans? 3) How long have you been running meth? Last edited by whats77inaname; 12152013 at 03:38 PM. 

Appreciate
0

12152013, 03:27 PM  #85  
Banned
0
Rep 47
Posts 
Quote:
When someone says it will accelerate at the same rate in every gear from 55007300 rpm, they're wrong, and I've highlighted why. 

Appreciate
0

12152013, 03:31 PM  #86 
Banned
0
Rep 47
Posts 

Appreciate
0

12152013, 04:38 PM  #87  
Lieutenant Colonel
62
Rep 1,987
Posts 
Quote:
You would normally be correct, but not with this particular engine's power/torque curves. Bruce 

Appreciate
0

Post Reply 
Bookmarks 
Thread Tools  Search this Thread 

