Highest Speeds on Sidewinder/Thundercat

[Bluebullet]

Stock 2021 SW LTX pulls speedo 115 -118 all day on decent long pulls with hard pack groomed trails. best speed on top in county rail bed 105 last weekend was 120 speedo and 114 GPS. Maybe next year I will take the orange secondary off my apex and try it on my winder and check for gains. Motorhead we should hook up!

 

[SideHogger]

This was the 132 mph pass. But I have to give credit to all the great people on this site and info on here. I'm just an old drag racer always trying to go fast!!!! What really stinks is that we never had great conditions to run some top speeds this year. Just makes you look forward to next year I guess!!! Lmao Special shout out to Mr. Knapp for all his help and info. Thank you sir.

 

[Sidewindo]

On my stock SW mtx 153 I can get the speedo to read 160km is approximately 660 ft. I can feel the sled stop pulling around the 400ft. My clutches are fully shifted out with low 21/52 (2.47 ratio). Without a tune and only a gearing change what speed can I safely aim for without track damage. This is a 3'' powder claw trimmed to 2.25" single ply. I understand the tracks sort of balloon with increased track speed. Any advice with these single ply tracks without studs.

 

[Motorhead]

Stock 2021 SW LTX pulls speedo 115 -118 all day on decent long pulls with hard pack groomed trails. best speed on top in county rail bed 105 last weekend was 120 speedo and 114 GPS. Maybe next year I will take the orange secondary off my apex and try it on my winder and check for gains. Motorhead we should hook up!

Yes we should hook up next year Bluebullet!

 

[Big_Phil]

Top speed runs are very gearing dependent. Stock 21/41 is 1:1 ratio at about 117mph. Gear it up if you want to go fast.

 

[Erskin]

yes they are, I found 21/41 in my tuned tcat would pull about 125 on hardpack groomed trail and just run out of gear. But a great all around gear combo for me where I ride.

 

[Fleecer]

My 2018 RTX isn’t crazy fast but is decently quick. Best 660’ off hard pack snow is 114.8 on GPS. Set up is a pro-mod engine build with a big turbo and TAPP clutching. It’s only geared for 120 at 1:1. This run was max performance pump gas set at 140Kpa, 20.4 psi. I use it as an everyday trail sled with full suspension/full weight. As an added bonus it gets better fuel mileage than my other 998s (one tuned, one stock) As a comparison, my 1200 turbo doo (pump gas) ran 116 in 660’.

Brent,
That's darn good speed in 660. Would you mind sharing a little more info such as tune, turbo size, boost, estimated horsepower, what engine build consisted of etc?

 

[Brent68]

Brent,
That's darn good speed in 660. Would you mind sharing a little more info such as tune, turbo size, boost, estimated horsepower, what engine build consisted of etc?

Sure, the engine was assembled local. Used the same person who did all the work to my 1200s. The engine builder is the best in the business but I’ve been sworn to keep it quiet. It has all the good internals. Dave at hurricane did a nitro head for me with big cams and +1 valves. He did work on the intake ports and cut the chambers to his hemi design. Dave said I would be able to add 3 degrees of timing with the head modifications and I can confirm this is accurate.

It has a custom header attached to a xona rotor 4948. This one flows enough for about 500hp. Finished with a modified sandale 3”including divorced waste gate exhaust. It has a big intercooler with Dave’s secondary intercooler. Using Motec for tuning, I do my own tunes. Not exactly sure on HP but if you use injector size, duty cycle and fuel pressure, the math indicates about 360 hp. This set up has boost at 20.4psi.

 

[number1kyster]

Yesterday I broke my top speed record in the County. I was running 126 on the gauge and it climbed up to 128 for a couple seconds. That may have been some track spin though. My GPS log read 123mph for the day.

 

[Fleecer]

Sure, the engine was assembled local. Used the same person who did all the work to my 1200s. The engine builder is the best in the business but I’ve been sworn to keep it quiet. It has all the good internals. Dave at hurricane did a nitro head for me with big cams and +1 valves. He did work on the intake ports and cut the chambers to his hemi design. Dave said I would be able to add 3 degrees of timing with the head modifications and I can confirm this is accurate.

It has a custom header attached to a xona rotor 4948. This one flows enough for about 500hp. Finished with a modified sandale 3”including divorced waste gate exhaust. It has a big intercooler with Dave’s secondary intercooler. Using Motec for tuning, I do my own tunes. Not exactly sure on HP but if you use injector size, duty cycle and fuel pressure, the math indicates about 360 hp. This set up has boost at 20.4psi.

Sounds like you've got quite a monster there! Thanks for sharing.

Quick question:. Since you have both intercoolers, which one lowered temps the most and/or which one is biggest bang for the buck? The big one in the front or the secondary one up top?

 

[Fleecer]

Yesterday I broke my top speed record in the County. I was running 126 on the gauge and it climbed up to 128 for a couple seconds. That may have been some track spin though. My GPS log read 123mph for the day.

Nice! At 123 GPS, I would wager 128 speedo is about right.

 

[Brent68]

Sounds like you've got quite a monster there! Thanks for sharing.

Quick question:. Since you have both intercoolers, which one lowered temps the most and/or which one is biggest bang for the buck? The big one in the front or the secondary one up top?

The goal was to make it as quick as my 1200 was. I got close. It’s a lot harder to make these things fast than making them quick. With a bunch of power and decent clutching they will get down the track. I wouldn’t even know where to start trying to get a trail sled up 144 mph…..that’s impressive!

I really didn’t put the second intercooler on to lower temps. It was required because I went with a Nitro head. I kept all the log files on this project so I could do a comparison. Because I only do shorter pulls and the boost is fairly low, intake temps were not much of a concern.

 

[Slow998]

The goal was to make it as quick as my 1200 was. I got close. It’s a lot harder to make these things fast than making them quick. With a bunch of power and decent clutching they will get down the track. I wouldn’t even know where to start trying to get a trail sled up 144 mph…..that’s impressive!

I really didn’t put the second intercooler on to lower temps. It was required because I went with a Nitro head. I kept all the log files on this project so I could do a comparison. Because I only do shorter pulls and the boost is fairly low, intake temps were not much of a concern.

From the sounds of things, it wouldn’t take you long and we’d be asking you questions on how to make our sleds go faster! We’ll be lake racing here in another week or two. Hopefully I can gain a couple mph.

 

[Upstater57]

125MPH on my 1100. I weigh too much and run too many studs to go faster. LOL

 

[Fleecer]

125MPH on my 1100. I weigh too much and run too many studs to go faster. LOL

Years ago, I had a 2013 F1100 Turbo with pipe and helix change. Dealer did a recall and updated the gearing. After that, it ran 128 mph speedo on groomed trail. That was pretty good back then for a stock machine.