markhuebbe Mark Huebbe Godlike Moderator Location: St. Louis, MO Join Date: 01/29/2007 Age: Midlife Crisis Posts: 41 Rally Car: 1970 VW Beetle (Historic) |
I'm having a transmission built and I have an almost unlimited choice in gear ratios. It's a 4 speed with a 4.57 R&P and ZF clutch LSD.
I was thinking about using a 3.44 1st, 2.25 2nd, 1.50 3rd, and 1.00 4th. Shifting would look like: 1st 3500 16mph - 7000 32mph 2nd 4680 32mph - 7000 48mph 3rd 4667 48mph - 7000 73mph 4th 4667 73mph - 7000 109mph (100mph @ 6450) Would I be better off sticking with a shorter 3rd & 4th? 1.56 & 1.09 3rd 4850 48mph - 7000 70mph 4th 4890 70mph - 7000 100mph With a RWD vehicle I don't know how often I'll see speeds over 100mph. Yet I don't know if I should have the engine screaming on a long straight at 90mph. http://www.huebberally.com |
Pete Pete Remner Elite Moderator Location: Cleveland, Ohio Join Date: 01/11/2006 Age: Midlife Crisis Posts: 2,022 |
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markhuebbe Mark Huebbe Godlike Moderator Location: St. Louis, MO Join Date: 01/29/2007 Age: Midlife Crisis Posts: 41 Rally Car: 1970 VW Beetle (Historic) |
I could put in: 3.11 1st, 2.25 2nd, 1.60 3rd, 1.14 4th.
1st 3500 17mph - 7000 35mph 2nd 5060 35mph - 7000 48mph 3rd 4978 48mph - 7000 68mph 4th 4988 68mph - 7000 96mph (4th - 82mph @ 6000 60mph @ 4400) The engine will make power from 5000-7000rpm. With a 4 speed I'm really limited on staying in the power band. I can always drop the top speed down from 100mph to shorten things up in the lower gears. I was just wanting to see what other people usually see for top speeds in their cars. Do Golfs see over 90mph in a rally? http://www.huebberally.com |
john vanlandingham John Vanlandingham Ultra Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
Mark you may want to look at whar "real" cars have and get as close as you can to them.
"Real" rally ratios typically have been like 2.25 to 2.4 for 1st, 1.6ish for 2nd, 1.16 to 1.2 for 3rd and 1:1 for top. And for cars with wheels the same size as your we have, oh! how convenient! Saab 96, and their rally ring and pinions were either 5.45 or 5.85. Do the percentage differences and run the numbers doing box x final so what you get for overall reduction per gear. In the second gearset all your ratios are fairly close, but shorter by about 15%, to the stock Borg Warner T5s that I say works "pretty good" for the TURBO boys, but are by no means "close". If that's all you have then that's all you have. You gotta do the math and then see. John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
markhuebbe Mark Huebbe Godlike Moderator Location: St. Louis, MO Join Date: 01/29/2007 Age: Midlife Crisis Posts: 41 Rally Car: 1970 VW Beetle (Historic) |
I guess my main question is what kinds of top speeds will I see out on the stages? If I only have 4 gears and a top stage speed of 95mph I can only space out my gears one way.
Your "real" rally car with a 5.45 r&p, 1:1 4th, and a tire that's 24"-25" will see a top speed of 93-95 mph at 7000 rpm. Is this the top speed that I should gear for? http://www.huebberally.com |
hoche Michel Hoche-Mong Senior Moderator Location: Campbell, CA Join Date: 02/28/2006 Age: Possibly Wise Posts: 1,156 Rally Car: Golf, Golf, RX-3 |
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turoc Ozgur Simsek Professional Moderator Location: Brooklyn, NY Join Date: 06/07/2006 Age: Midlife Crisis Posts: 561 Rally Car: working on a Veedub |
At every rally I ve been to in the US (all east coast) I have heard of speeds 110+ mph even in the 2wd category
Flat out top speeds are pretty common in the US. The rallies are less technical with less turns... Top speeds at WRC events are at about 200kph roughly 125mph. If the cars were geared for speed they should be able top that out... All this aside; I have mountain bike raced -XC for years and the races were always won during the climbs or flats. Everyone was fast at the downhills (BTW I was one of the fastest ) A few seconds gained on the downhill was easily wiped out on the way up. There is a huge difference being able to maintain a longer higher average speed vs staying flat out a few seconds . Guess in whose favor? Oscar rally gods would turn in their graves if they ever knew Lada's were now part of EU rallying!!! |
john vanlandingham John Vanlandingham Ultra Moderator Location: Ford Asylum, Sleezattle, WA Join Date: 12/20/2005 Age: Fossilized Posts: 14,152 Rally Car: Saab 96 V4 |
markhuebbe Wrote:
------------------------------------------------------- > I guess my main question is what kinds of top > speeds will I see out on the stages? If I only > have 4 gears and a top stage speed of 95mph I can > only space out my gears one way. > > Your "real" rally car with a 5.45 r&p, 1:1 Wait, I said "and for cars with wheels the same size as yours" Well my car with the 5.45 uses a 0.92 top or effectively about 5.1 ish overall in top. > 4th, and a tire that's 24"-25" And I use Michelin 14/62 x 15= 24.4" diameter. will see a top > speed of 93-95 mph at 7000 rpm. And I get just under 14.8 mph per 1000 rpm---I set the rev limiter at 7100 and that gives me a top speed of about 105mph. >Is this the top > speed that I should gear for? Well my car can pull max revs pretty easily, and I have not been to a rally where I don't hit the rev limiter in 4th, but its also lower, longer, and wider, and the steering is much better than a Beetle. So I can safely do it. On the other hand, I've seen Skoda 1.3s get into the top 12 on tarmac WRC in front of my nose in 1993 at MonteCarlo, and the did almost exactly 140 km'h or about 91mph. And my best over result in a National was back in 1995 at Lake Superior and I had the rev limiter forgotten at 6000, and that was barely 90, but I was setting top 5-6 stage times and had a couple of 3rds OVERALL on a few (and was sunk by 13 minutes of brain fade from the co-driver screwing up "desired in times" at MTCs) So I guess its really about the 25 to 90 range that's most critical. > > John Vanlandingham Sleezattle, WA, USA Vive le Prole-le-ralliat www.rallyrace.net/jvab CALL +1 206 431-9696 Remember! Pacific Standard Time is 3 hours behind Eastern Standard Time. |
markhuebbe Mark Huebbe Godlike Moderator Location: St. Louis, MO Join Date: 01/29/2007 Age: Midlife Crisis Posts: 41 Rally Car: 1970 VW Beetle (Historic) |
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Josh Wimpey Josh Wimpey Junior Moderator Location: VA Join Date: 12/27/2006 Age: Midlife Crisis Posts: 649 Rally Car: Sneak the Golf |
markhuebbe Wrote:
------------------------------------------------------- > Do Golfs see over 90mph in a rally? > > Yes, even with a 4.24R&P and stock ratios, we have seen 5th gear 110+ (Rally NY, and Rally TN) and plenty of 4th gear redline at pretty much every event. Sometimes I decide that redline in 4th is fast enough and back off instead of hitting 5th. ____________________________________________________________- One. Class -- 2WD www.quantumrallysport.com http://www.facebook.com/home.php?#/pages/Quantum-Rally-Sport/281129179600?ref=nf |
Like all have said "GAAAAH! WIDE!" or something to that effect. Your gear numbers look like a stock Opel trannie and they did not work well in rallying (tho your 2-3 spacing is better). Steps similar to what John said, although the numbers may need to be a bit higher for a 4.57 R&P; like the mid to upper 2's for 1st, the upper 1's for 2nd, and so on.
The steps should get smaller as you go up in gear, not stay the same % change. You start to really have wind resistance start to eat up HP as you hit 3rd, so that's one reason to make the % steps smaller. You'll spend 98-99% of your time in the lower speed ranges; if you are on the limiter a bit, it will SEEM like forever, and can be irritating, but don't let it bother you; you have to mkae the best you can out of 4 speeds, not 5 or 6, so concentrate on the middle speed. Actually % time lost is minimal. Since you are in the MW, you will run events like 100 AW and Ojibwe and LSPR and Rally TN. You could hit the top limits every now and then, but I would not base my gearing on it. RNY is not a good example of what you will be seeing typically, and even STPR has only a few spots with high speeds. Good luck! Mark B. |