New Quadshot here...

Quote from Kyle D

If we are talking about road racing and 1/4mi drags, yes weight savings is crucial. However, I have yet to find a road racing track that will let a 3 wheeled slingshot run with cars or motorcycles. But in 1/2mi top speed runs, weight becomes less important but adding down force (essentially MORE weight) to stay planted does become more important so you can deliver the power to the ground efficiently. As far as tops go, most of the tops out there are not terribly heavy since they are made out of light weight tubing and canvas or plastic and poly but either way performance is going to be more affected by the additional drag created and not the actual weight of it. I would say that it is safe to say that the majority of this niche market is not concerned about shaving ounces and pounds though. Especially when you can just brute force your way through it with a turbo.

just for informational purposes TravAZ has done a good deal of track time with his Slingshot on the track with the cars I dont remember which group it was that was allowing him to run, but perhaps he can chime in here with than information

this is one of his many track videos

Quote from edwardaneal

just for informational purposes TravAZ has done a good deal of track time with his Slingshot on the track with the cars I dont remember which group it was that was allowing him to run, but perhaps he can chime in here with than information

this is one of his many track videos

I'm sure there are tracks out there. But none of the ones in MI allow them and none of the tracks on the Gridlife circuit would allow them. We do not go out much further than those so it was pointless for me to look further.

A stock slingshot has three separate battles when pushed hard (over 70%) on the track.

Terrible Aerodynamics

Lack of rear traction

Awful brakes

The first one really only rears its head on the long straights, everywhere else the first two are far worse. But the big front fenders, you know those floppy dog ear things bouncing around by the front tires, actually create lift at speed and the open cockpit creates dirty air and drag. Those "canards" on the front lip, those are for telling you where the curb at the 7/11 is because they don't do anything else. When the speeds start to push anything over 100 MPH the aero of the sling is a huge hurdle.

The traction issue is more complex. The sling is WIDE at the front and fairly well planted across its front tires. It's stiff sway bar, meant to keep that back tire sitting flat, does a good job of reducing body roll. The biggest problem with a vehicle with three points of contact with the ground is lateral instability. It will want to Tip Over when pushed hard around a corner rather than slide. To keep this from happening Polaris did three things: They put the most mass over the axis between the two wheels (the motor), they placed the center of gravity as low as possible (about 13" high) and they made it very wiiiiiide. This works to keep it from flipping over but it comes at a high cost.

Low weight over the drive wheel at the rear.

The resulting lack of traction in the back creates a pretty bad oversteer situation. You can do a little to help this by widening the rear tire and mixing tire compounds front to rear to try to balance it out but it is never going to be ideal. An actual functioning rear wing can create some downforce but it would have to look like a McLaren Senna back there to get results that would do much good. The stock sling is fun at the track, sure, but when pushed anywhere near hard, the first thing that will pass you at the track will be the rear end of your own slingshot. Not trying to advocate for anything here but adding another rear tire really helps

Now back to that long front straight away..... the second or third time you hit it you may want to lighten up a little on the loud pedal because that middle pedal that is supposed to stop you is gonna be a little spongy. LIke, "holy crap that gravel trap is getting closer!!!" kind of Spongy. Again, a fourth one of those calipers thingies helps but even then whatever tractor they borrowed the front calipers off of was never intended to be a track tool. If you are going to track the sling once a year in group 3 or 4 get some GOOD pads. If you are making it a weekend warrior and want to be that pesky annoying guy in the mirror of those vettes and vipers in group 1 and 2 (mustangs will be behind you or in the grass. PS- I hate mustangs) then you'll want to get some real track brakes. Radial mounted calipers and rotors that look like a device meant to stop you, not looking like a little tin plate to eat you pizza off of.

You can have fun driving anything at the track and I highly encourage anyone to go. Even if you go as slow as possible track time will improve your driving skills and it is much safer than pushing past 70% on the road. No cops, no oncoming traffic (except for mustangs), lots of fun.

One of my favorite quotes for you, from F1 driver Martin Brundle:

Over steer is hitting the wall with the back of the car,
Under steer is hitting the wall with the front of the car,
Horsepower is how fast you hit the wall,
And Torque is how far you move the wall once you've hit it.

Over steer is hitting the wall with the back of the car,
Under steer is hitting the wall with the front of the car,
Horsepower is how fast you hit the wall,
And Torque is how far you move the wall once you've hit it.

Great quote!

Quote from TrakHamr

A stock slingshot has three separate battles when pushed hard (over 70%) on the track.

Terrible Aerodynamics

Lack of rear traction

Awful brakes

The first one really only rears its head on the long straights, everywhere else the first two are far worse. But the big front fenders, you know those floppy dog ear things bouncing around by the front tires, actually create lift at speed and the open cockpit creates dirty air and drag. Those "canards" on the front lip, those are for telling you where the curb at the 7/11 is because they don't do anything else. When the speeds start to push anything over 100 MPH the aero of the sling is a huge hurdle.

The traction issue is more complex. The sling is WIDE at the front and fairly well planted across its front tires. It's stiff sway bar, meant to keep that back tire sitting flat, does a good job of reducing body roll. The biggest problem with a vehicle with three points of contact with the ground is lateral instability. It will want to Tip Over when pushed hard around a corner rather than slide. To keep this from happening Polaris did three things: They put the most mass over the axis between the two wheels (the motor), they placed the center of gravity as low as possible (about 13" high) and they made it very wiiiiiide. This works to keep it from flipping over but it comes at a high cost.

Low weight over the drive wheel at the rear.

The resulting lack of traction in the back creates a pretty bad oversteer situation. You can do a little to help this by widening the rear tire and mixing tire compounds front to rear to try to balance it out but it is never going to be ideal. An actual functioning rear wing can create some downforce but it would have to look like a McLaren Senna back there to get results that would do much good. The stock sling is fun at the track, sure, but when pushed anywhere near hard, the first thing that will pass you at the track will be the rear end of your own slingshot. Not trying to advocate for anything here but adding another rear tire really helps

Now back to that long front straight away..... the second or third time you hit it you may want to lighten up a little on the loud pedal because that middle pedal that is supposed to stop you is gonna be a little spongy. LIke, "holy crap that gravel trap is getting closer!!!" kind of Spongy. Again, a fourth one of those calipers thingies helps but even then whatever tractor they borrowed the front calipers off of was never intended to be a track tool. If you are going to track the sling once a year in group 3 or 4 get some GOOD pads. If you are making it a weekend warrior and want to be that pesky annoying guy in the mirror of those vettes and vipers in group 1 and 2 (mustangs will be behind you or in the grass. PS- I hate mustangs) then you'll want to get some real track brakes. Radial mounted calipers and rotors that look like a device meant to stop you, not looking like a little tin plate to eat you pizza off of.

You can have fun driving anything at the track and I highly encourage anyone to go. Even if you go as slow as possible track time will improve your driving skills and it is much safer than pushing past 70% on the road. No cops, no oncoming traffic (except for mustangs), lots of fun.

One of my favorite quotes for you, from F1 driver Martin Brundle:

Over steer is hitting the wall with the back of the car,
Under steer is hitting the wall with the front of the car,
Horsepower is how fast you hit the wall,
And Torque is how far you move the wall once you've hit it.

Display More

Excellent information. Very informative.

Dave@DDMWorks has the numbers to show effiency of the angle drive vs. A normal differential. The SC they sell for the Sling as what is in the Soltice. The Sling dynos about 35 HP higher than the Soltice with the same boost set up at the rear wheels.

If I remember correctly (been about 2 years since I heard info).

I have somewhere between 10-12 track events with my Slingshot. The group I ran with is called ProAutosports and they are still allowing Slingshots to participate if anyone is interested and around AZ. http://www.new.proautosports.com/   It took some time to get the Slingshot approved, but they have been awesome and the events have been really fun. I have quite a few track videos posted on youtube, but got really busy to edit and post some of the more recent ones.

Most of what is stated above is spot on. It took me a long time to figure out the right tire/wheel setup for the Slingshot to get it to really feel confident while pushing hard at the track. I also would never turn off the stability control, only the traction control would be off. Rear traction is always the issue with the Slingshot and I can confirm the removing the front fenders improves aero and vehicle feedback at high speeds. The big roll hoop mounted rear wings never really helped at the track that I noticed, and I didn't care for how much they vibrated at high speeds. I have driven/ridden in Slingshots with stock brakes and never really thought they were that bad. With the correct bleeding procedure, a brake brace, and halfway decent pads, you should be ok. Maybe I never pushed a stock setup that hard. My machine had the Alpha Big Brake Kit and was probably a bit overkill for a 1,800lb machine. No matter how hard you drove it, you couldn't get brake fade.

Still looking for someone to buy my track (aggressive street) wheel and tire setup. Let me know if anyone is interested in a proven setup.

Quote from TrakHamr

A stock slingshot has three separate battles when pushed hard (over 70%) on the track.

Terrible Aerodynamics

Lack of rear traction

Awful brakes

The first one really only rears its head on the long straights, everywhere else the first two are far worse. But the big front fenders, you know those floppy dog ear things bouncing around by the front tires, actually create lift at speed and the open cockpit creates dirty air and drag. Those "canards" on the front lip, those are for telling you where the curb at the 7/11 is because they don't do anything else. When the speeds start to push anything over 100 MPH the aero of the sling is a huge hurdle.

The traction issue is more complex. The sling is WIDE at the front and fairly well planted across its front tires. It's stiff sway bar, meant to keep that back tire sitting flat, does a good job of reducing body roll. The biggest problem with a vehicle with three points of contact with the ground is lateral instability. It will want to Tip Over when pushed hard around a corner rather than slide. To keep this from happening Polaris did three things: They put the most mass over the axis between the two wheels (the motor), they placed the center of gravity as low as possible (about 13" high) and they made it very wiiiiiide. This works to keep it from flipping over but it comes at a high cost.

Low weight over the drive wheel at the rear.

The resulting lack of traction in the back creates a pretty bad oversteer situation. You can do a little to help this by widening the rear tire and mixing tire compounds front to rear to try to balance it out but it is never going to be ideal. An actual functioning rear wing can create some downforce but it would have to look like a McLaren Senna back there to get results that would do much good. The stock sling is fun at the track, sure, but when pushed anywhere near hard, the first thing that will pass you at the track will be the rear end of your own slingshot. Not trying to advocate for anything here but adding another rear tire really helps

Now back to that long front straight away..... the second or third time you hit it you may want to lighten up a little on the loud pedal because that middle pedal that is supposed to stop you is gonna be a little spongy. LIke, "holy crap that gravel trap is getting closer!!!" kind of Spongy. Again, a fourth one of those calipers thingies helps but even then whatever tractor they borrowed the front calipers off of was never intended to be a track tool. If you are going to track the sling once a year in group 3 or 4 get some GOOD pads. If you are making it a weekend warrior and want to be that pesky annoying guy in the mirror of those vettes and vipers in group 1 and 2 (mustangs will be behind you or in the grass. PS- I hate mustangs) then you'll want to get some real track brakes. Radial mounted calipers and rotors that look like a device meant to stop you, not looking like a little tin plate to eat you pizza off of.

You can have fun driving anything at the track and I highly encourage anyone to go. Even if you go as slow as possible track time will improve your driving skills and it is much safer than pushing past 70% on the road. No cops, no oncoming traffic (except for mustangs), lots of fun.

One of my favorite quotes for you, from F1 driver Martin Brundle:

Over steer is hitting the wall with the back of the car,
Under steer is hitting the wall with the front of the car,
Horsepower is how fast you hit the wall,
And Torque is how far you move the wall once you've hit it.

Display More

Pretty good analysis. That being said, I find that my stocker SS handles, and stops, much better than any of the English sports cars I have owned/driven.

I think one huge advantage to 4 wheels on the SS would be driving in the rain.... it’s hard to avoid ponding in heavy rains with 3 wheels, I know as I have been through a lot of storms, never seems to fail I catch 1 wheel hitting a deep spot and makes ya tighten up in seat area!

Quote from JoeF.

I think one huge advantage to 4 wheels on the SS would be driving in the rain.... it’s hard to avoid ponding in heavy rains with 3 wheels, I know as I have been through a lot of storms, never seems to fail I catch 1 wheel hitting a deep spot and makes ya tighten up in seat area!

Turn the NANNIE's off

Always do!!!!

From the photos I have seen, it makes me question if the rear exhaust is still a possibility with this kit?

Quote from 2W2X1

From the photos I have seen, it makes me question if the rear exhaust is still a possibility with this kit?

With a little modification it should be. SlingDrop had his modified for his bulletspeed kit.

I'm going to have to modify my exhaust as well, my dual welters won't fit with the trakhamr. I plan to do something similar to slingdrops

SlingDrop (or anyone who knows) what brand/model are those tires that you are using?

Quote from Neosolidus

SlingDrop (or anyone who knows) what brand/model are those tires that you are using?

Neosolidus He is running Toyo Proxes T1R. 285s up front and 305s in the rear on 20" wheels

For straight line racing I would want as much weight transfer as I could get. A soft shock in the back and some 10/90's in the front. When you leave the line the 10 out on the front would cause the front to lift and the soft shock in the back would squat. This would cause weight to transfer to the rear wheel. Then as the speed increased the 90 in would allow the front to drop down for better aero. Did this in the drag cars and it worked pretty good, but we had two rear wheels. Just a thought.

LC

She's back and pretty...I am ridiculously happy with it and will be doing a full video review on it this week during SSITR

Here is what I don't understand. When you slap on a 4th wheel how do you get away with continuing to register as an autocycle? Wouldn't local laws prohibit that? And what about car requirements for bumpers etc? Does that only apply to Polaris or are you subject to those laws once you convert the autocyle to by all definitions a car?

On a different note, I would love to see what the 0 to 60 numbers are with the turbo and 4 wheel kit.

Quote from neostar

Here is what I don't understand. When you slap on a 4th wheel how do you get away with continuing to register as an autocycle? Wouldn't local laws prohibit that? And what about car requirements for bumpers etc? Does that only apply to Polaris or are you subject to those laws once you convert the autocyle to by all definitions a car?

On a different note, I would love to see what the 0 to 60 numbers are with the turbo and 4 wheel kit.

I looked in to it extensively here in Colorado...so laws might change depending on your state. Colorado has no vehicle inspection. So essentially you are on an honor system. Once you register your vehicle, you have a renewal...it can be done over the phone or on line. Colorado also has some of the most relaxed laws when it comes to kit cars, registering vehicles to be worthy...so on and so on. We haven't become hyper insane like Massachusetts or California. With that being said...I checked with 2 lawyers, local sheriffs in multiple counties, 2 state troopers, and local PD in my area. All of them essentially came back with "You have no infractions you can be cited for." Essentially telling me there are no laws I am breaking in Colorado. They could possibly hit me with a secondary offense ticket if they really wanted to...but as the quote that was said more often than note "That LEO would be either a big asshole or having a hell of a bad day." With that being said...I drove from Michigan, through Indiana, Illinois, Iowa, and Nebraska....saw law enforcement in small towns and state patrol on the highway...I got more thumbs up and waves from them than I ever did prior.