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Philosophy of Gearing

Posted by dunhamr1 
john vanlandingham
John Vanlandingham
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Re: Philosophy of Gearing
June 16, 2017 08:01PM
Gentlemen! GENTLEMEN!

When the range of knowledge and experience is so broadly spread as is here dotcha thing a smrat first step would be to define what IS cool..
Then compare the coolest car in this parsec of the galaxy to what is available

Compare and contrast.. Numbahs.



John Vanlandingham
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Robert Culbertson
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Re: Philosophy of Gearing
June 16, 2017 08:09PM
Quote
john vanlandingham
Gentlemen! GENTLEMEN!

Someone's been watching AvE.
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hoche
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Re: Philosophy of Gearing
June 16, 2017 08:28PM
Quote
john vanlandingham
Gentlemen! GENTLEMEN!

When the range of knowledge and experience is so broadly spread as is here dotcha thing a smrat first step would be to define what IS cool..
Then compare the coolest car in this parsec of the galaxy to what is available

Compare and contrast.. Numbahs.

Well, fine, John, but most people haven't driven a Trabant.



Self-righteous douche canoe
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fiasco
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Re: Philosophy of Gearing
June 16, 2017 09:02PM
Quote
Robert Culbertson
Quote
john vanlandingham
Gentlemen! GENTLEMEN!

Someone's been watching AvE.

I thought JV WAS AvE with a voice change. smiling smiley



Andrew Steere
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KB1PJY
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Pete
Pete Remner
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Re: Philosophy of Gearing
June 16, 2017 09:22PM
Short final drives are awesome with solid axles because the shorter your ring and pinion are, the less driveshaft torque affects tire loading. Tall final drives really want to spin that bakaksel around like a propellor.



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john vanlandingham
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Re: Philosophy of Gearing
June 16, 2017 11:57PM
Quote
Robert Culbertson
Quote
john vanlandingham
Gentlemen! GENTLEMEN!

Someone's been watching AvE.

Not a clue what the reference is to...



John Vanlandingham
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Robert Culbertson
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Re: Philosophy of Gearing
June 17, 2017 03:24AM
Quote
john vanlandingham
Quote
Robert Culbertson
Quote
john vanlandingham
Gentlemen! GENTLEMEN!

Someone's been watching AvE.

Not a clue what the reference is to...

Enjoy...


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Not Trolling
Keith Morison
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Re: Philosophy of Gearing
June 21, 2017 12:13PM
When I think of gearing, I think back to the first time I competed in a 'real' open class car. It was an ex-Pat Richard car from Rocket and had a 5 speed dogbox and while I don't know what the final drive was, the car had the 'right' gearing, and accelerated like mad.
Now, the real proof is that we blew 5th early in the event, so ended up running Helmer (a stage we knew well and had good benchmarks for) without 5th.
Our top speed was down by over 20km/h compared to the P4(PGT) wrx we had been running, which isn't a shocker. (The stage is downhill with a few sections we can let the car run in)
What was a surprise was that our stage time was 1.5sec/km FASTER, even without 5th, and in the first event for the car in our hands.(and won the stage outright)

That tells me that gearing for acceleration pays greater dividends than focusing on top speed. But of course you'll want to find a balance.
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john vanlandingham
John Vanlandingham
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Re: Philosophy of Gearing
June 21, 2017 03:19PM
Quote
Not Trolling
When I think of gearing, I think back to the first time I competed in a 'real' open class car. It was an ex-Pat Richard car from Rocket and had a 5 speed dogbox and while I don't know what the final drive was, the car had the 'right' gearing, and accelerated like mad.
Now, the real proof is that we blew 5th early in the event, so ended up running Helmer (a stage we knew well and had good benchmarks for) without 5th.
Our top speed was down by over 20km/h compared to the P4(PGT) wrx we had been running, which isn't a shocker. (The stage is downhill with a few sections we can let the car run in)
What was a surprise was that our stage time was 1.5sec/km FASTER, even without 5th, and in the first event for the car in our hands.(and won the stage outright)

That tells me that gearing for acceleration pays greater dividends than focusing on top speed. But of course you'll want to find a balance.

Well duh..
Over 90% of what we do is running from about 40 km/hr or 25 mph up to about 90 mph again and again...and again... Contrary to the North American Old Salty sea-dog old wives tail, it IS a drag race between corners.. Acceleration is supreme... That obnoxious guy who knows everything while in reality is a crash more often than not SS1 crasher was blabbering once--well often--and said "The FASTEST car always wins" proof that he's just a stupid punk kid who know shit...
Quick --rate of acelleration is what counts.
Torque in the motor x gear x final= AX (should be slang for acceleration..it is in some languages)

Now all North American SSs are FAST by world standards..Some are ridiculously fast..When you have 3 rate talents like Block and Higgins averaging over 80mph on SSs on the same weekend as fans are screaming their heads off about Ogier and Latvala averaging 74mph in Finland you know its simple roads, not talent,.
So we want AX but we want it everywhere from 24 to 90 or where ever you chicken out at..

Hence the beauty of the T5 2.95 gearset..1st and second with a 4.3 or 4.37 are not stupid short. The car goes forward, not digging holes downward.

...but 3rd and 4th are shorter overall for more AX in those gears..

1:1 Top, 65cm tire and 4.3 axle gives @7000 rpm about 122-123 mph..PLENTY of speed...and, it'll get you there quickly..

Then stick it in 5th for comfy leisurely transits...



John Vanlandingham
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Not Trolling
Keith Morison
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Re: Philosophy of Gearing
June 21, 2017 10:07PM
Quote
john vanlandingham
Well duh..
Easy to grunt, but the fact that the thread exists means it isn't as obvious to some as it is to you or I.

Quote
john vanlandingham
Contrary to the North American Old Salty sea-dog old wives tail, it IS a drag race between corners.. Acceleration is supreme...
And by driving cleaner and starting off faster coming out of the corner your stage times will drop [/stating the bloody obvious]
Quote
john vanlandingham
That obnoxious guy who knows everything while in reality is a crash more often than not SS1 crasher was blabbering once--well often--and said "The FASTEST car always wins" proof that he's just a stupid punk kid who know shit...
Great to see you still don't shy away from cutting people down for no good reason. 'That obnoxious guy' wasn't even in this conversation until you decided to bring him into it for no reason other than kicking him while he's not paying attention.

Quote
john vanlandingham
Quick --rate of acelleration is what counts.
Well duh. [/humerous mockery]
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john vanlandingham
John Vanlandingham
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Re: Philosophy of Gearing
June 21, 2017 10:41PM
Quote
Not Trolling
Quote
john vanlandingham
Well duh..
Easy to grunt, but the fact that the thread exists means it isn't as obvious to some as it is to you or I.

Quote
john vanlandingham
Contrary to the North American Old Salty sea-dog old wives tail, it IS a drag race between corners.. Acceleration is supreme...
And by driving cleaner and starting off faster coming out of the corner your stage times will drop [/stating the bloody obvious]
Quote
john vanlandingham
That obnoxious guy who knows everything while in reality is a crash more often than not SS1 crasher was blabbering once--well often--and said "The FASTEST car always wins" proof that he's just a stupid punk kid who know shit...
Great to see you still don't shy away from cutting people down for no good reason. 'That obnoxious guy' wasn't even in this conversation until you decided to bring him into it for no reason other than kicking him while he's not paying attention.

Quote
john vanlandingham
Quick --rate of acelleration is what counts.
Well duh. [/humerous mockery]


The cunt needs more cutting down..After all his bullshit talk he's a Jokes... The asshole is a classic troll, the bane to reasonable conversation..he mocks me with his stupid screen name so as long as he does, I'll ridicule his bullshit like crashing on the first stage as a classic dumbshit noob mistake which it is.. Really over 50% DNF rate unchanging over the years..he's a hazard.

The thread exists because others want to try and counter-balance the BS that gets passed off as sage advice...



John Vanlandingham
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DanielSL
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Re: Philosophy of Gearing
June 22, 2017 07:10AM
Based off of what you guys are saying, I believe my pick for a budget RX box was good. It looks like I am good as far as the final drive ratio, 1st, 4th, and 5th gears.

Any recommendations on what should be done for 2nd and 3rd gears? More equal spacing, perhaps?

I am going to add an LSD over the winter, and since the box will be out of the car, it will be the right time to do any work internally. I have an ample supply of spares from other boxes, so with the right advice, I can put together that might be more competitive while still using stock O2J box ratios.

Thanks.
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Attachments:
open | download - O2J Box Specs.jpg (59.3 KB)
O2J Box Specs.jpg
dunhamr1
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Re: Philosophy of Gearing
June 22, 2017 07:43AM
Quote
DanielSL
Based off of what you guys are saying, I believe my pick for a budget RX box was good. It looks like I am good as far as the final drive ratio, 1st, 4th, and 5th gears.

Any recommendations on what should be done for 2nd and 3rd gears? More equal spacing, perhaps?

I am going to add an LSD over the winter, and since the box will be out of the car, it will be the right time to do any work internally. I have an ample supply of spares from other boxes, so with the right advice, I can put together that might be more competitive while still using stock O2J box ratios.

Thanks.

Picking and choosing gear ratios for individual gears generally isn't "budget" but if you've got spares and the skills and time to do it, then it shouldn't hurt you too much.

For RX, I would imagine that the final drive ratio (while relevant for total gearing calculations) wouldn't come into play.

How often are you getting out of second gear? How often do you downshift to 1st? If you make 1st gear "taller" (lower numerically) you could be able to shift better into first for the one slow corner. If 2nd gear is taller then you could avoid having to shift into 3rd thereby gaining time because you're not shifting.



I started this thread because I was curious, and I'm currently building a car and looking at options and recommendations I'm getting and wondering what is important and are certain features worth it?

Full disclosure, I have driven 2x rally in my life, in a Subaru of all things (not really my choice). I compete regularly as a stage rally Codriver though and try to take some perspective from there. I'm just looking to learn, to improve and increase the collective knowledge as well, by initiating this discussion. So far, lots of good info, let's keep it going.
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DanielSL
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Re: Philosophy of Gearing
June 22, 2017 07:54AM
I appreciate the discussion, Ryan. I was able to source two EGT code boxes, for $100 each, and then two other code O2J boxes for $75 and $80, with the same final, but different 2nd thru 4th ratios, and one with a different 5th.

So, in essence, I have a good tranny, a full spare, and 2 more spares with the same F.D., all for around $350. I didn't mean to buy that many, just a couple of deals fell into my lap.

For RX, the launch is the only time I'm in 1st. Second gear, mostly bouncing off the rev limiter for the entire course. Depending on course design, there may be one straight where I am forced to shift to 3rd - but then the car bogs down - even with the turbo.

So, I've been thinking about changing 3rd. 1.75 would basically be in the middle of where 2nd and 3rd are now. There is a stock 1.475 I can source, from the other O2J boxes.

I am thinking (Dangerous, I know); that when I start attending Rally Sprints up at the FIRM, that because of the length of the course, I will be jumping up to 3rd quickly, and running out of room.


For reference, the Eurospec Rally Long gear box is geared as:

Rally Long 1st: 2.7, 2nd: 1.8, 3rd: 1.45, 4th: 1.15, 5th: .89



Edited 1 time(s). Last edit at 06/22/2017 08:01AM by DanielSL.
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Robert Culbertson
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Re: Philosophy of Gearing
June 22, 2017 01:33PM
Quote
hoche
Quote
Robert Culbertson
On the RWD cars that I have played with, the 1st-2nd gap is huge, so I've focused on 2-5th with a short final drive. The low 1st is nice for loading it on the trailer and cruising the service park at a reasonable speed.

And that's the way a lot of people do it. The problem is that you end up driving on a teeny fifth gear that was designed to be an overdrive, and a ring&pinion with really small teeth.

With the T5 trans 5th isn't really that physically small, and you can swap to a the 0.8 5th which is gigantic. The small r&p, that's definitely something to worry about when you have lots of torque in the motor. The 4.88 in the dana 30 (7.2in ring gear dia) has been happy with the 16v motor, the axles... not so much. Can't really fault the axles though. Welded diff for a long time, and then running with only 1 rear brake and the locker was locked the entire time... so one axle was getting fully reversed loading, and bending.

Here are a few screen grabs from a gearing calculator that I built up a while back.
T5z, T5z with 0.8 5th, and a Mustang T5. Have fun!

T5zModvsT5z Trans Ratio by

T5vsT5z Trans Ratio by
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