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Old 03-06-2011, 07:36 PM   #586
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I would run 4S with the 2650kv. If you use 3S with the stock gearing (51T spur, 13T pinion) it would only be geared for about 25mph which is very slow. On 4S with stock gearing you'd get to about 35mph (which is still a bit slow). I'd start with a 15T pinion which will be about 40mph and go from there based on temps and performance.

I have always been told 40mph is a good place to start out with a 1/8 vehicle. For the first run check temps often to judge how it's behaving. This is the calc I use to setup gearing on all my vehicles, the site also has lots of other useful calcs and tools:

http://www.scriptasylum.com/rc_speed/top_speed.html
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Old 03-06-2011, 08:23 PM   #587
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Originally Posted by simplechamp View Post
I would run 4S with the 2650kv. If you use 3S with the stock gearing (51T spur, 13T pinion) it would only be geared for about 25mph which is very slow. On 4S with stock gearing you'd get to about 35mph (which is still a bit slow). I'd start with a 15T pinion which will be about 40mph and go from there based on temps and performance.

I have always been told 40mph is a good place to start out with a 1/8 vehicle. For the first run check temps often to judge how it's behaving. This is the calc I use to setup gearing on all my vehicles, the site also has lots of other useful calcs and tools:

http://www.scriptasylum.com/rc_speed/top_speed.html
Are you using Tekin Hot Wire to setup your ESC?
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Old 03-06-2011, 11:14 PM   #588
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......

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Old 03-06-2011, 11:54 PM   #589
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The gearing in the calc for the older original GTP is not the same as the GTP2e, the GTP2e uses typical 43/13 buggy ratio. It's in the list as "Misc Typical Buggy Ratio - 3.31:1"

Also, I generally use 3.7V/cell as the voltage, as that's what the cells are likely to be at when loaded. That is what the creator of the calc BrianG told me to use. I leave the motor current and resistance blank, and I've always found it to still be pretty accurate, enough to get you where you want to be. You can also leave tire ballooning at 0 providing you run belted tires. I only enter ballooning for off-road vehicles where it's much more significant.

I assume this is going to be a speed run vehicle? Because with the numbers as they are that's about all it will be good for. Definitely pushing the RPM, so keep the runs short when using 6S. The calc says 118mph, but the calc loses accuracy quickly once you go past 40-50mph, as friction and air resistance become a much bigger factor. I would say the true speed will be much less than 118.

For a general starting point on my 1/8 vehicles I shoot for 40mph, 30-40k RPM, rollout between 1:1 and 1.5:1. That has worked very well for me so far, and has always yielded cool running setups with room to gear up for more speed if wanted. Better to start too slow than to overgear and fry something right away.

Bubblehead: I'm using a Mamba Max Pro ESC, so I won't be using the HotWire, but I do use the CastleLink to adjust the settings via PC.
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Last edited by simplechamp; 03-07-2011 at 12:13 AM.
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Old 03-07-2011, 04:44 AM   #590
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[QUOTE=simplechamp;8757886]I would run 4S with the 2650kv. If you use 3S with the stock gearing (51T spur, 13T pinion) it would only be geared for about 25mph which is very slow. On 4S with stock gearing you'd get to about 35mph (which is still a bit slow). I'd start with a 15T pinion which will be about 40mph and go from there based on temps and performance.

I have always been told 40mph is a good place to start out with a 1/8 vehicle. For the first run check temps often to judge how it's behaving. This is the calc I use to setup gearing on all my vehicles, the site also has lots of other useful calcs and tools:


Been playing around with that vehicle speed calculator. 40mph is pretty slow for onroad if you wanna get close to the nitro GTs. All of our nitro GTs are in the lower 50mph range on our rather long straight(~200ft). I shot my GTP-E with a Stalker Pro gun and got 53.2mph on a 200 foot straight run. Using the top speed software I get a speed of 54.58 which is pretty darn close. That speed is calculated if you leave the current draw blank. The speed doesn't very much plugging in 40-200 amp draw numbers. I'm running 4S 5000 30C geared 47/23 with a Tekin 2050KV. ESC timing is 40 at a rpm band of 20-30K. Thanks for the link. It's an useful tool.
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Old 03-07-2011, 05:41 AM   #591
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Thanks for the comments. I'm new to 1/8 GT so the 40mph was based from my off-road experiences. Good to know because I'm in the final stages of setting up my car and will gear a bit faster now.

BTW, be sure to check out all the other tools on that site, lots of helpful stuff. I think he's currently in the process of adding a spring rate calculator, we had talked about it briefly. I was looking for springs for my GT and noticed that the Ultra GTP, Ofna DM-1, and Inferno GT springs aren't rated in the standard lb/in units, which makes it hard to compare them. With the calculator you will be able to find the rate in lb/in for any spring (without a special testing device, just calipers to take measurement), and it will make it much easier to compare the springs.
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Old 03-08-2011, 03:39 AM   #592
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Been playing around with that vehicle speed calculator. 40mph is pretty slow for onroad if you wanna get close to the nitro GTs. All of our nitro GTs are in the lower 50mph range on our rather long straight(~200ft). I shot my GTP-E with a Stalker Pro gun and got 53.2mph on a 200 foot straight run. Using the top speed software I get a speed of 54.58 which is pretty darn close. That speed is calculated if you leave the current draw blank. The speed doesn't very much plugging in 40-200 amp draw numbers. I'm running 4S 5000 30C geared 47/23 with a Tekin 2050KV. ESC timing is 40 at a rpm band of 20-30K. Thanks for the link. It's an useful tool.[/QUOTE]

Where do you get the 47/23 gearing from for the GTP-E? Where can I purchase these from?
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Old 03-09-2011, 07:49 AM   #593
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Where do you get the 47/23 gearing from for the GTP-E? Where can I purchase these from?[/QUOTE]

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Old 03-09-2011, 03:13 PM   #594
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Hi guys! My first time posting on the board. I am new to the boards and new to 1/8th scale on road having raced 1/8th scale off road and 1/10 tc for years now. I just got my GTP2E and am in the process of final setup, but had a couple of questions.

1) What is the popular motor choice? I will be running an RX8 and it seems that most of you are running the 2650 but some are running the 2200? Any further insite would be great. It will be running at a prepped track with a 200ft straight and tight infield for the most part, but occasionally i would like to run an open setup (bashing) for fun as well.

2) For those that are racing this chassis seems that the popular tire is the sweep 50's? Treaded for dusty tracks and slicks for well prepped? What other mods are giving you best bang for the buck?

3) What spring are you guys running?

4) Battery choice, i guess this would depend on what kv motor i choose but any advice would be helpful.

Thanks in advance, i have read the entire gtp2e posts and will try to contribute as soon as i get mine up and running.

Thanks, Jonathan

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Old 03-10-2011, 06:34 AM   #595
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Quote:
Originally Posted by canucksfan77 View Post
Hi guys! My first time posting on the board. I am new to the boards and new to 1/8th scale on road having raced 1/8th scale off road and 1/10 tc for years now. I just got my GTP2E and am in the process of final setup, but had a couple of questions.

1) What is the popular motor choice? I will be running an RX8 and it seems that most of you are running the 2650 but some are running the 2200? Any further insite would be great. It will be running at a prepped track with a 200ft straight and tight infield for the most part, but occasionally i would like to run an open setup (bashing) for fun as well.

2) For those that are racing this chassis seems that the popular tire is the sweep 50's? Treaded for dusty tracks and slicks for well prepped? What other mods are giving you best bang for the buck?

3) What spring are you guys running?

4) Battery choice, i guess this would depend on what kv motor i choose but any advice would be helpful.


Thanks in advance, i have read the entire gtp2e posts and will try to contribute as soon as i get mine up and running.

Thanks, Jonathan

Wild Bill(IGT Hobbies) runs a Tekin 2050 and 2250. The 2250 on larger tracks. He's been running GTs successfully for a while now. I think he can go 10 minutes on a charge. Those are the motors I went with as well. I've been test when weather permits. The 2050 has lotsa torque and goes 53+mph on a 200 foot straight. Geared 47/23 on 4S 30C lipos. For high speed bashing just strap on a 6S lipo. Speed calculator comes up with 78mph with that set up. Gotta watch temps.

45 Sweeps are the best on our track. 50 Sweeps are for hotter climates. Taller gears are a needed mod. Not sure but the hardened steel diff rings might be needed. I had to replace both the Kyosho stock diff rings for the nitro GT car.

The stock GTP shocks feel good to me. Feels very similar to my Kyosho GT set up. I won most of our GT-N club races.

I get all lipos from Hobby King USA. 4S 30C 5000-7200mah. Under $50 a pack.

This about all the info I have for now. Anxious for the weather to break here in NW Ohio so I can do some track testing.
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Old 03-10-2011, 11:28 AM   #596
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Can you post a link to some different option Spurs? I can't find them. And does anyone know who sells Thunder Power lipos at the best price? Thanks!
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Old 03-10-2011, 02:46 PM   #597
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Quote:
Originally Posted by rcwck View Post
Anxious for the weather to break here in NW Ohio so I can do some track testing.
rcwck.... Would you PM me when you know your going to the track for testing please ?

I've been working on my gtp2e for 3 weeks now.
I'll have most of the parts next week.

2200kv Neu 1415 1y, two 4s 40/50c 2200mah lipo's and some experimental custom made stuff to try out.

There are 4 of us now from Lazer speedway that have our 1/8th cars and more will be getting theres soon.

Anxious....Thats an understatement
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Old 03-11-2011, 11:06 AM   #598
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thanks for the info rcwck,

Can you guys confirm the center diff is OFN31325 and the corresponding 47tooth spur is OFN40247. Are these #'s correct?

If i run a center diff is that the only spur option? Assuming i run a 47t spur and 4s with a 2050 or 2250 where should i start for pinions?


Thanks guys
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Old 03-11-2011, 11:13 AM   #599
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Quote:
Originally Posted by canucksfan77 View Post
thanks for the info rcwck,

Can you guys confirm the center diff is OFN31325 and the corresponding 47tooth spur is OFN40247. Are these #'s correct?

If i run a center diff is that the only spur option? Assuming i run a 47t spur and 4s with a 2050 or 2250 where should i start for pinions?


Thanks guys
the 31325 is right but the spur you need is 30110

Start with 16 pinion
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Old 03-11-2011, 12:27 PM   #600
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isnt the 30110 the stock 51 tooth?

I am looking for the 47 tooth spur.

Thanks, Jonathan
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