JR 3 springs.

[JGR32]

I’m building a JR3 motor and I’m wondering what would be the beat valve springs for this application?

 

[OVALTECH1]

Any of the legal 10.8 springs setup correctly. I like the Dover reds but you’ll soon hear them all im sure.

 

[1fasttiller]

Dover reds, Dyno Green Stripes and the WMS Tuck and Run springs are all top choices. Pick one and go!

 

[JGR32]

Dover reds, Dyno Green Stripes and the WMS Tuck and Run springs are all top choices. Pick one and go!

I started with the Dyno yellow stripes but there were a little too stiff so I’m gonna go with the greens.

 

[Petty Race Engines]

Do you have a way to check those reds to make sure that they pass tech ? Those springs are a builders spring and a lot of blueprinting goes into those to get them right, they may not pass tech straight out of the box

 

[Raging Bull Engines]

Dover reds, Dyno Green Stripes and the WMS Tuck and Run springs are all top choices. Pick one and go!

Yep. Pick good springs.

 

[1fasttiller]

Yep. Pick good springs.

You must certainly do so! Our little Jr3 motor spun 6950 last weekend

 

[Raging Bull Engines]

You must certainly do so! Our little Jr3 motor spun 6950 last weekend I

I thought for sure he had the pro race won.

 

[1fasttiller]

I thought for sure he had the pro race won.

Us too... apparently the finish line is several feet BEFORE the flagstand there.... it was a photo finish for sure!

 

[Raging Bull Engines]

Us too... apparently the finish line is several feet BEFORE the flagstand there.... it was a photo finish for sure!

How convenient

 

[JGR32]

You must certainly do so! Our little Jr3 motor spun 6950 last weekend

6950 and we’d be gearbound for sure.

 

[1fasttiller]

6950 and we’d be gearbound for sure.

We definitely wasn’t gear bound. My son turned the fastest lap in that class and led quite a few laps. This particular track has a ton of drop in the corners and No bite so unfortunately you have to spin em a little higher. Although i ended up dropping a tooth for the main and we stayed around 6700 all night.

 

[JGR32]

We definitely wasn’t gear bound. My son turned the fastest lap in that class and led quite a few laps. This particular track has a ton of drop in the corners and No bite so unfortunately you have to spin em a little higher. Although i ended up dropping a tooth for the main and we stayed around 6700 all night.

Our engine fell off bad at 6500. We were turning 6550 one day and we couldn’t keep up. Dropped one tooth and we were back in the mix.

 

[VenomPower4]

I’m building a JR3 motor and I’m wondering what would be the beat valve springs for this application?

Even if you get pre set springs for your engine you still have to check them to make sure they will be legal for your rules!

 

[Raging Bull Engines]

You must certainly do so! Our little Jr3 motor spun 6950 last weekend

Because I don't pay attention, I had no idea who the motor was for when I built it. I was glad to hear it was for you guys. You all made it look good.

 

[Raging Bull Engines]

6950 and we’d be gearbound for sure.

Could be kart and tire issues. The worse the kart and tires are, the lower the rpm will need to be closer to peak power rpm to be fast. As the kart and tires get better and absorb less power to run a given MPH, the further past peak power you can turn it and still be as fast or even faster. Then there is the motor........

 

[payneracing714]

Could be kart and tire issues. The worse the kart and tires are, the lower the rpm will need to be closer to peak power rpm to be fast. As the kart and tires get better and absorb less power to run a given MPH, the further past peak power you can turn it and still be as fast or even faster. Then there is the motor........

is that being said if you are on the right gear to begin with?

 

[Raging Bull Engines]

is that being said if you are on the right gear to begin with?

The right gear depends on how the kart is rolling that day. Different setups and tires require different rpm to be fast with the same motor.

 

[JGR32]

Setup was baseline numbers from Phantom and cut tires with medium prep 100,100,60 inside. 6 and 7 psi.

 

[racing promotor]

Regardless what gearing you use for an I'll handling kart or one with wrong tires on you'll never get it to it full potential by adjusting gearing only.