Philosophy of Gearing

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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.

I think you would be better off with the 1st and 2nd from an EGX box 3.3 and 1.944 or the 2nd from an EUH box 2.063

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Josh Wimpey

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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.

I think you would be better off with the 1st and 2nd from an EGX box 3.3 and 1.944 or the 2nd from an EUH box 2.063

Josh it's not going to make any difference to anything for this guy..Its a grassy filed..And how do you measure if its worth some hundreds of dollars and 10-5 hours work? For nothing...

As usual this guy makes himself the center of a discussion which really he has no connection with..Gearing for a rally car in a rally on ROADS driving from 25 to 90mph again and again and again and again, has nothing to do at all with driving around on a flat field in 2nd gear... He isn't discussing he's fapping... Grass-o-cross = fap-o-cross....

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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.

Josh;

The EGX numbers look like they would be interesting to work with. I may try to source and install this 1-2 combo when I put in the LSD. Then the trans will be more ready for the length and speeds of the Rally Sprint course up at the FIRM. Now that we will have a full season of RX under its belt, its time to progress the car up to Sprint status, and get a season of Sprints driving on top of another season of RX driving. Hopefully by then, I will start feeling like I have enough experience with how the car reacts to bring it to Sand Blast and wring it all the way out.


Thanks.

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DanielSL
Josh;

The EGX numbers look like they would be interesting to work with. I may try to source and install this 1-2 combo when I put in the LSD. Then the trans will be more ready for the length and speeds of the Rally Sprint course up at the FIRM. Now that we will have a full season of RX under its belt, its time to progress the car up to Sprint status, and get a season of Sprints driving on top of another season of RX driving. Hopefully by then, I will start feeling like I have enough experience with how the car reacts to bring it to Sand Blast and wring it all the way out.


Thanks.

A WHOLE season..

I wonder how many actual minutes that is? 20 minutes? 25?

Realistically the gearbox isn't going to make any difference at some rally-sprint..

Stop thinking..
Just drive more.. OK?

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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.

Quote
john vanlandingham
As usual this guy makes himself the center of a discussion which really he has no connection with..Gearing for a rally car in a rally on ROADS driving from 25 to 90mph again and again and again and again, has nothing to do at all with driving around on a flat field in 2nd gear... He isn't discussing he's fapping... Grass-o-cross = fap-o-cross....

All this.

My opinion for non rally? 2nd gear should be just short enough that tire spin isn't a problem. So maybe 4550mph top if you have decent grip and power. Accelerating out of corners is way more important than accelerating at the top end. 1st gear is just to get moving, 3rd is there if you need it, but you MUST be able to accelerate out of a slow corner in 2nd because the first part of a straight is way more important than the second part. Better to accelerate fast to moderate speed than to accelerate more liesurely to a momentarily higher speed.

Acceleration more important than speed, sounds familiar yeah?

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

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john vanlandingham

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DanielSL
Josh;

The EGX numbers look like they would be interesting to work with. I may try to source and install this 1-2 combo when I put in the LSD. Then the trans will be more ready for the length and speeds of the Rally Sprint course up at the FIRM. Now that we will have a full season of RX under its belt, its time to progress the car up to Sprint status, and get a season of Sprints driving on top of another season of RX driving. Hopefully by then, I will start feeling like I have enough experience with how the car reacts to bring it to Sand Blast and wring it all the way out.


Thanks.

A WHOLE season..

I wonder how many actual minutes that is? 20 minutes? 25?

I've had singular events where there were 20 minutes of timed runs. One-day events with times in the 15 minute range...

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Stop thinking..
Just drive more.. OK?

THIS. Stop thinking, just drive, then think AFTER THE FACT what could have made you faster. Accelerating more quickly and accelerating from a higher speed always makes you faster, so focusing on what is keeping you from doing those two things is important...

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Pete Remner
Cleveland, Ohio

1984 RX-7 (rallycross thing)
1978
Silence is golden, but duct tape is silver.

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

Well step one would be not listening to you, most have realized that though

You seem awfully invested in disliking somebody you've never met, I'm sorry that your life is so meaningless for that to be the case. It does warm my heart to know you are thinking about me though You probably have some parts that are a year behind in the making, maybe less interneting and more doing work is in order?

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dreamsofjvl

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

Well step one would be not listening to you, most have realized that though

You seem awfully invested in disliking somebody you've never met, I'm sorry that your life is so meaningless for that to be the case. It does warm my heart to know you are thinking about me though You probably have some parts that are a year behind in the making, maybe less interneting and more doing work is in order?

You seem awfully invested in shit talking somebody you never met, especially considering you modest and extrememly limited results and the duration of time and efforts you have expended doing nothing but shit talking.

Maybe you go and eat shit and die..

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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.

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Robert Culbertson

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hoche

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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

So the GM V8 Camaro box has the same ratios as the Z-spec box? Nifty.

I've built a similar calculator with graphs, and it looks like your also getting the speed deltas between gears? or is that the difference between the two different types of trans/diff combos?

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john vanlandingham

Maybe you go and eat shit and die..

Hmm, probably not for quite a while. You on the other hand old man... Only a matter of time. And then you will really be forgotten, not even be a hasbeen or neverbeen.

Keep on keepin on Junior Varsity

It's the speed delta between gears at a certain rpm.
I chose 7k, as that's usually where Derek shifts the Volvo.

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Robert Culbertson
It's the speed delta between gears at a certain rpm.
I chose 7k, as that's usually where Derek shifts the Volvo.

Got it.

Which trans/diff combo are you guys running now?

T5z with the "Sebring" 0.8 5th and a 4.88. The 5.29 R&P might be just the ticket for an NA car with that trans gearing.

The GM T5 does have a nice gearing spread, especially if you pick-up the model with the .74 5th. Drop it in and go racing... assuming you can find an adapter plate for the GM pattern.

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Robert Culbertson
T5z with the "Sebring" 0.8 5th and a 4.88. The 5.29 R&P might be just the ticket for an NA car with that trans gearing.

What kind of top speed would that yield? 120 calculated seems really fast. (assuming you were trying to gear for acceleration in rally.

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Robert Culbertson
The GM T5 does have a nice gearing spread, especially if you pick-up the model with the .74 5th. Drop it in and go racing... assuming you can find an adapter plate for the GM pattern.

Yes, that's true. I've got one of the GM T5s but it's got a .63 5th gear.. might play mix and match and throw the 5th gear from a 3.35 box on it, and swap everything over into the Ford case. Idk if I ever want to get that deep into it though..

Ryan,
Double check the number of teeth and the ratios. The ratio in 5th is also controlled by the input shaft gear and cluster/counter gear tooth counts. So swapping just 5th might not actually be the change you're looking for. For instance, using the 0.80 5th with a 3.35 1st drops the OD closer to 0.9...

As far as gearing, the 4.88 is still a bit too high, but it's way better than the stock 4.1 that was in the car originally. Switching to a 5.29 would drop the top speed, and up the accel.
I see the point is using 1-4 and a longer final drive, but you'll be stuck in each gear longer and loosing time vs using 1-5 and a shorter final drive.