Rally Speed

[Bulldogger]

Ok did some speed testing bone stock, wife's old phone wouldn't work but luckily a Sheriff stopped by and Radar gun it. 30mph does that sound about right for bone stock with HPI filter?


Just want to make sure because I want to put the jetpro pipe on and see if there is a difference.

 

[Ice_2k]

Not sure what gearing the rally has but 30mph seems a little on the low side. Did you tune the HSN to reach top rpms?

 

[Bulldogger]

I didn't want to lean it out too much as it is new. Are the gears marked?

 

[Ice_2k]

Rally Speed

You can count the teeth on the wheels. Then there's also the final drive that might have a different ratio. My gearbox gears (DuneRunner) have a ratio of 0.987 (29-31-26-24) but the final ratio is 9:1 (9 engine revolutions for one wheel revolution). This gets me ~40mph at almost 17.000rpm

I saw most gas 5th scales are advertised as 35mph when stock.

 

[Bulldogger]

Okay looks like they are 29-31-26-24, not sure which order the 26 and 24 go

 

[Ice_2k]

The 31 is the one connected to the 29 and on the same axis as 26

 

[Bulldogger]

You can count the teeth on the wheels. Then there's also the final drive that might have a different ratio. My gearbox gears (DuneRunner) have a ratio of 0.987 (29-31-26-24) but the final ratio is 9:1 (9 engine revolutions for one wheel revolution). This gets me ~40mph at almost 17.000rpmI saw most gas 5th scales are advertised as 35mph when stock.

Okay same gear ratio should it be doing 35 stock then?

 

[Ice_2k]

Rally Speed

I don't know what the ratio of the final drive is on the rally and also I don't know the size of your wheels (smaller wheels = lower top speed at the same engine rpm and ratios) so I can't say for sure

 

[Bulldogger]

Okay are the gears in the differentials different for each model?. I would think for cost reasons differentials would all be the same.

 

[Ice_2k]

You can do what I did: tape a little piece of duct tape on the outside of the clutch bell, roll the car on the ground and count how many times the bell goes around for the wheels to go around one complete time. If you get smth close to 9:1, then we have the same ratio.

Then measure the distance the car goes for a complete turn of a wheel and use that to compute how many wheel rpm that means for 30mph. Multiply that by 9 and you'll find your engine's top rpm If it's not in the vecinity of at least 16,000, you're probably not tuned right.

 

[RampageHopUps]

You have to wait for at least 5 tanks to get it broken in. After that, it will start performing better.

 

[Bulldogger]

You can do what I did: tape a little piece of duct tape on the outside of the clutch bell, roll the car on the ground and count how many times the bell goes around for the wheels to go around one complete time. If you get smth close to 9:1, then we have the same ratio. Then measure the distance the car goes for a complete turn of a wheel and use that to compute how many wheel rpm that means for 30mph. Multiply that by 9 and you'll find your engine's top rpm If it's not in the vecinity of at least 16,000, you're probably not tuned right.

Same ratio 9:1 that covered 19" on the ground. I don't know if it makes much of a difference but my car has the 30.5cc engine and you have the 32cc correct

 

[Ice_2k]

Rally Speed

That means you were topping at ~15.000 rpm which is more than enough if you're just breaking it in, I wouldn't rev it that high if you're not done with the breakin.

As far as the speed difference is concerned, it looks like you have smaller diameter wheels. I'm covering 22" with one wheel rotation, not just 19".

 

[Bulldogger]

I have done the breaking that was illustrated on O'Niel brothers racing. I am at the tuning stage basically. Momma tried to use a speed gun app on her Apple phone but that was a bust. Was going to do top speed runs till it slowed then richen it up. It gets up to speed really fast so I figured it would be safe being it is starting out rich.

 

[RampageHopUps]

I will look around for one of my old hiking GPS. The iPhone isn't meant for the small bursts of speed.

 

[Ice_2k]

It depends on the iPhone model. I tested with an iPhone 6 and the SpeedTracker app and it works great, you only need to maintain the top speed for 1-2 seconds for it to properly record it. On an older iPhone 4 however it was unusable, it would need over 10 seconds of constant speed to stabilize. By the way, we're obviously talking about apps that read the phone's speed, so the phone needs to be attached to the car. You can't have an actual "speed gun" app as there's no radar hardware on the iPhone.

Btw, you can get a tachometer that attaches to your car and reads the RPM. That's what I used in the beginning until I bought a new radio with telemetry and now I can see my speed/RPM/temp on the transmitter.

 

[Bulldogger]

It depends on the iPhone model. I tested with an iPhone 6 and the SpeedTracker app and it works great, you only need to maintain the top speed for 1-2 seconds for it to properly record it. On an older iPhone 4 however it was unusable, it would need over 10 seconds of constant speed to stabilize. By the way, we're obviously talking about apps that read the phone's speed, so the phone needs to be attached to the car. You can't have an actual "speed gun" app as there's no radar hardware on the iPhone. Btw, you can get a tachometer that attaches to your car and reads the RPM. That's what I used in the beginning until I bought a new radio with telemetry and now I can see my speed/RPM/temp on the transmitter.

Momma was using a baseball app. We are going to attach the phone to the buggy today there is a GPS speed app that worked pretty good on the older phone. I put the Jetpro pipe on and I don't think the tires are long for this world It is a lot louder but low end grunt definitely increased

 

[Ice_2k]

that pipe looks great You can get a silencer for it if it's too loud.

 

[Bulldogger]

that pipe looks great You can get a silencer for it if it's too loud.

Dino included one free of charge when I bought it. The silencer is kind of funky looking. I run the buggy at an abandoned airport so it isn't bothering anyone. He even included heat wrap, really nice guy to deal with.

Next set of tires would you go with tarmac tires or slicks?? Hopefully if the weather holds today I am going to make a couple more passes for speed. I am going to switch the 29 and 31 gears see how it does and next week put on the 990 carb.

 

[Ice_2k]

I had the tarmac busters (here's my opinion of them: http://www.redcatrampageforum.com/showthread.php?p=155589#post155589) and now I bought a set of slicks in the hope of better durability but I haven't mounted them yet as we're under snow here in Europe.