07 RTX Testing today(gear change 22/38 & 23/38) Results

[canapex]

I know this has been talked about several times.I did my own testing today.I used the same section of river with snow packed and ice spots.
My 1st test was 23/38 gear with a 70 link chain. I pulled 113 mph (GPS)at 10,600 rpms (max) one way & 110 mph back the other way(if there was any wind).I did try another belt I had,same thing 110 to 113 mph every time,the dream meter said 125-127 mph.

My next test after taking it home and changing to 22/38 with a 68 link chain then going back to same spot an hour later.Results were very close 111 mph (GPS)both ways at get this, 11,000 rpms and pulled very hard.I never changed anything else but the gearing.

I would have to say the 22/38 gearing works much better and is faster for sure.It pulled the 111 mph in less distance then the 23/38 did.I did mark the primary clutch and there was a 1/4 inch left on the primary with the 23/38 but with the 22/38 there was about an 1/8 th left.So yes under ideal conditions the 23/38 will pull more mph,it was only -13 today so I am sure at -25 it will pull 117-118 but if you get on any kind of snow and the 23/38 will not pull the mph and will be slower getting there as well.

 

[rapeape]

Nice test, thanks.

 

[LazyBastard]

Overdrive your clutches and throw some more weight at your primary and I think you'll get back those last 2 mph. You're loosing some power by spinning your engine too fast.

 

[number1kyster]

I dont think the 07 RTX needs anything. It is the only sled i've ever owned that IMO was perfect stock.

 

[canapex]

I never bought anything that was fast enough......

 

[schmeg]

I'm glad I went with 23/39 on my Apex 136. I didn't have to buy a different chain and it's close to 22/38 in ratio. I had also been tracking different postings about the best way to hook these babys up and the 136 is THE best way.

 

[87gtNOS]

Re: 07 RTX Testing today(gear change 22/38 & 23/38) Resu

My next test after taking it home and changing to 22/38 with a 68 link chain then going back to same spot an hour later.Results were very close 111 mph (GPS)both ways at get this, 11,000 rpms and pulled very hard.I never changed anything else but the gearing.

You are running on RPM...bring the RPM back down and you'll run 105.
I would also wonder if you could somehow have TIMED your runs that the 23t gear would be QUICKER to the finish also, as it was revving 10600, making more power(edit, added this>>), than the 22t at 11000.

 

[SledFreak]

From the testing that I have seen is that if you spin that motor @10,800-11,000, it's the best way to get high mph out of it. At the start it should go to 10,300-10,500, then slowly climb to 10,900-11,000. Let the torque of the motor pull the sled up to 80-90, then let the hp pull it the rest of the way. On a short drag you would not want it to spin that high, but on a long run it helps alot.

 

[chadman]

The 07 rtx has a 22 tooth top gear stock, correct?

 

[number1kyster]

yes

 

[69redmach1]

I did similar testing last year with my 07 RTX. On glare ice the 23 tooth had a faster speed by a couple mph but on any other conditions the 22 was faster and accelerated better. I ended up keeping the 22 tooth gear.

 

[Mikecam]

Keeping my 22 top as well.

 

[SumpBuster]

I'm pretty happy with my rtx as is, but the rpm thing is really noticeable on our grass drag strip. Last month, I couldn't pull over 10,200 and would get indicated mph's high 80's to one 91. It was hooking and ratcheting hard in the clay. On wet grass, I spun more and the rpm went to about 10,500 and then to 11000 and was pulling indicated high 90's same distance. On a long pull, I want to see 11000. Sled really pulls on top if you get the rpm up. Just a seat of the pants observation, for what it's worth.

 

[canapex]

Was on Netley creek on Sunday and ran into another 07 RTX. Not sure if anything was done to it.It had a couple guages on the console and the guy even had the same jacket as me lol.
I pulled along side of him at 50-60 mph an we both got on it hard,as soon as we nailed it I started to pull on him and kept on pulling until 110 mph and we had to hit the brakes for a corner. My sled on a roll goes to 10,500 right away and hits 11,000 very fast and just stays at 11,000 rpms with the 22/38 gearing.The funny thing is it would not do that with the 23/38 gearing,the best I did see was 10,600 10,700 It just does not feel as fast with the 23 gear in there. I wonder if I through some more weight at the clutch and pull down the rpms a little if it will pull more mph with the stock 22/38 gearing? Anyone?

 

[Charged RTX]

You will always pick up rpm with lower gearing. I would add enough weight so it comes out at 10,500 to 10,600 and maxes out at about 10,900.