Fastest HPI Sport 3

[Redback]

It's been a while and a chassis I have wanted to get for a long time.

Got a spicy 2 pole brushless and high speed gearing ready to drop.
Anyone else speed ran one of these, I've seen people get 108mph so i know the car can do it.

Got a propper speed run shell for it this time too, no more launching into the sky.

 

Plan:
Do 150+mph get 200kmph hat.
2s - 4s.
Low drag body.

Custom carbon fiber splitter.

2x 2s-2p 3200mha HV 120c lipo

 

Been impressed with the HPI Savage flux's durability on 4s, diffs holding strong at 70+mph, so I'm excited to see what this will do at Rossa this year.
Fairly sure it will blow the FTX banzai's 108mph away.

 

Build pics to follow then a cheeky quick test run.

[Lone-wolf]

2 hours ago, Redback said:

It's been a while and a chassis I have wanted to get for a long time.

Got a spicy 2 pole brushless and high speed gearing ready to drop.
Anyone else speed ran one of these, I've seen people get 108mph so i know the car can do it.

Got a propper speed run shell for it this time too, no more launching into the sky.

 

Plan:
Do 150+mph get 200kmph hat.
2s - 4s.
Low drag body.

Custom carbon fiber splitter.

2x 2s-2p 3200mha HV 120c lipo

 

Been impressed with the HPI Savage flux's durability on 4s, diffs holding strong at 70+mph, so I'm excited to see what this will do at Rossa this year.
Fairly sure it will blow the FTX banzai's 108mph away.

 

Build pics to follow then a cheeky quick test run.

will be interesting to see how it goes, still not sold mine but not splitting it so looks like im stuck with it

[Redback]

40 minutes ago, Lone-wolf said:

will be interesting to see how it goes, still not sold mine but not splitting it so looks like im stuck with it

Send it, it would be nice to get a brushed bench mark and worth a drive if its not going anywere anytime soon right?

[PraetoR]

Sounds like an interesting project. Good luck with it! 

[Lone-wolf]

11 hours ago, Redback said:

Send it, it would be nice to get a brushed bench mark and worth a drive if its not going anywere anytime soon right?

might put the gps on it and see how fast it is at weekend, my guess is 38mph with the 15t motor on 2s

[Redback]

The "Comet" build begins

 

[Stormbringer]

Should look good hurtling down the track at Rossa and good luck 

[Redback]

Thanks chaps, forgot hpi screws were cheese, already rounded 2 getting the servo plate out.
Esc fits snugly behind the small motor, if a longer can is needed then id have to forward mount the servo, still might do it to free up some chassis space.

 

Most annoying is the inability to run contact foams as the wheels hit these little bumps on the rear A arms. Could grind them off, think its for a grubnut but cant see any there and they give a spare set 😄

[Lone-wolf]

tidy build, hope you get some big numbers, are you using a steering gyro, i found this chassis does handle pretty well......also gathers dust well sat in the storage space

[Redback]

Slow gearing out, stock High speed gearing in.

 

Could go a little more crazy as pinions fit the 5mm drive shaft, woot!

 

Seeing what else will work, if the servo is moved out the way.

[Redback]

3 hours ago, Lone-wolf said:

tidy build, hope you get some big numbers, are you using a steering gyro, i found this chassis does handle pretty well......also gathers dust well sat in the storage space

No gyro, as it can make the car loose control at high speeds, trying to self correct oscillation in the steering.

[Redback]

Body fitment, as expected had to do some trimming off the front towers nothing drastic.

[Lone-wolf]

I was gonna put my speed flea GPS on my RS4 but sent it up in a flying wing sunday and crashed as the motor ripped of, bye bye speed flea its now in a crop field somewhere

[Grogg]

How far can you modify the HPI Sport 3 - does it come as a rolling chassis or in a kit that needs to be assembled it's quite taken my fancy as well, before it's no longer a HPI Sport 3?

 

  I've been wondering about this since I first got into the hobby and started to build my Rock Socker, less than 50% of the parts I used to build that are from the Tamiya Rock Socker kit, most of the parts I used aren't even made by Tamiya, the TT-02 SRX that I have lined up to build for my next challenge with my mates, I'm not exaggerating when I say, I'd be extremely surprised if I use 15-20% of the parts that came in the kit if not less, is it still a TT-02 if I use less than 20% of the parts the kit comes with, and instead substitute them with say gears from HPI, Koysher and RW Racing, drive train from Yeah Racing, shocks from GMade..... and even say use the gears out of a TT-01 and DT-03 instead of the TT-02 gears - the TT-01 speed spur gear set includes a 55T and 58T spur gear the speed spur gear set for the TT-02 is 67T or 68T the diffs on the DT-03 are identical size and shape as the ones on the TT-02 except that they are made out of metal instead of plastic.

Edited April 28, 2023 by Grogg

[Lone-wolf]

19 hours ago, Grogg said:

How far can you modify the HPI Sport 3 - does it come as a rolling chassis or in a kit that needs to be assembled it's quite taken my fancy as well, before it's no longer a HPI Sport 3?

 

  I've been wondering about this since I first got into the hobby and started to build my Rock Socker, less than 50% of the parts I used to build that are from the Tamiya Rock Socker kit, most of the parts I used aren't even made by Tamiya, the TT-02 SRX that I have lined up to build for my next challenge with my mates, I'm not exaggerating when I say, I'd be extremely surprised if I use 15-20% of the parts that came in the kit if not less, is it still a TT-02 if I use less than 20% of the parts the kit comes with, and instead substitute them with say gears from HPI, Koysher and RW Racing, drive train from Yeah Racing, shocks from GMade..... and even say use the gears out of a TT-01 and DT-03 instead of the TT-02 gears - the TT-01 speed spur gear set includes a 55T and 58T spur gear the speed spur gear set for the TT-02 is 67T or 68T the diffs on the DT-03 are identical size and shape as the ones on the TT-02 except that they are made out of metal instead of plastic.

Buy mine and work with that ha ha, its already way faster than a TT02

[Redback]

21 hours ago, Grogg said:

How far can you modify the HPI Sport 3 - does it come as a rolling chassis or in a kit that needs to be assembled it's quite taken my fancy as well, before it's no longer a HPI Sport 3?

 

  I've been wondering about this since I first got into the hobby and started to build my Rock Socker, less than 50% of the parts I used to build that are from the Tamiya Rock Socker kit, most of the parts I used aren't even made by Tamiya, the TT-02 SRX that I have lined up to build for my next challenge with my mates, I'm not exaggerating when I say, I'd be extremely surprised if I use 15-20% of the parts that came in the kit if not less, is it still a TT-02 if I use less than 20% of the parts the kit comes with, and instead substitute them with say gears from HPI, Koysher and RW Racing, drive train from Yeah Racing, shocks from GMade..... and even say use the gears out of a TT-01 and DT-03 instead of the TT-02 gears - the TT-01 speed spur gear set includes a 55T and 58T spur gear the speed spur gear set for the TT-02 is 67T or 68T the diffs on the DT-03 are identical size and shape as the ones on the TT-02 except that they are made out of metal instead of plastic.

I haven't done any mods, they say add a washer to stop the back ring pinion slop.

As noted you can fit pinions on the driveshaft, this is good because the only other gearing choice is the high speed set and I hear these melt. Probably some metal c hubs as they seem weak.

[Grogg]

On 29/04/2023 at 17:59, Redback said:

I haven't done any mods, they say add a washer to stop the back ring pinion slop.

As noted you can fit pinions on the driveshaft, this is good because the only other gearing choice is the high speed set and I hear these melt. Probably some metal c hubs as they seem weak.

 

You can get custom spur gears made to any pitch and tooth count you want, and it is nowhere near as expensive as it sounds.

[Redback]

14 minutes ago, Grogg said:

 

You can get custom spur gears made to any pitch and tooth count you want, and it is nowhere near as expensive as it sounds.

Indeed but theres no need when any 5mm bore pinion will fit, thus making any pinion a spur gear, thus saving the need for any custom cuts.
As you can see here i have a small pinion as a spur in the rs4 to see if it works.

 

I did the same with the banzai even popped mod 1 in there.

 

Edited April 30, 2023 by Redback

[Grogg]

On 30/04/2023 at 20:53, Redback said:

Indeed but theres no need when any 5mm bore pinion will fit, thus making any pinion a spur gear, thus saving the need for any custom cuts.
As you can see here i have a small pinion as a spur in the rs4 to see if it works.

 

I did the same with the banzai even popped mod 1 in there.

 

 

 

That's very very interesting being able to use a 5mm bore pinion gear as a spur gear.  I haven't started to build my TT-02 yet for the challenge my mates and I have to build one with FPV that will go over 100mph, and I've just treated myself to a HPI Savage XL Flux V2 GTXL-6, now I'm wondering if it would be too greedy of me, or obsessive - I know own 4 RC cars 2 1/8 scale and 2 1/10 scale,  to buy myself one, if it came in kit form instead of a rolling chassis, I would be all over it and to hell if it's being greedy or too obsessive.  What body shell or shells have you got for it, if you don't mind me asking?

[Redback]

On 05/05/2023 at 01:15, Grogg said:

  What body shell or shells have you got for it, if you don't mind me asking?

The only shell i intend to run is the delta plastic porche shell, shown in the images. Its very heavy and 2mm thick.
Would have cost over 100£ if imported, managed to snag the last one on modelsport.
https://www.modelsport.co.uk/product/1349081

[Grogg]

On 08/05/2023 at 16:01, Redback said:

The only shell i intend to run is the delta plastic porche shell, shown in the images. Its very heavy and 2mm thick.
Would have cost over 100£ if imported, managed to snag the last one on modelsport.
https://www.modelsport.co.uk/product/1349081

 

Thanks for the info.  I bought 4 body shells for the challenge I'm doing with mates to build a TT-02 that goes over 100mph. 

 

Any plans of reinforcing the body shell?  I'm considering doing it, a number of the speed runners that I've been watching on YouTube who are are getting over 100mph seem to do it, that Australian Youtuber Stew Mac I think he's called, he also posts over on the Tamiya club forum, in the speed section, does it with carbon fibre, on his channel and a thread on the Tamiya club he shows you how he does it, in the thread he explains why, others I've seen use reinforcement tape, dry waller tape and shoo goo.

[Redback]

9 hours ago, Grogg said:

 

Thanks for the info.  I bought 4 body shells for the challenge I'm doing with mates to build a TT-02 that goes over 100mph. 

 

Any plans of reinforcing the body shell?  I'm considering doing it, a number of the speed runners that I've been watching on YouTube who are are getting over 100mph seem to do it, that Australian Youtuber Stew Mac I think he's called, he also posts over on the Tamiya club forum, in the speed section, does it with carbon fibre, on his channel and a thread on the Tamiya club he shows you how he does it, in the thread he explains why, others I've seen use reinforcement tape, dry waller tape and shoo goo.

No I got a 2mm thick body for that exact reason, it doesnt need reinforcing its thick enough to take impacts and not flex under load.

The issue is stopping the body mounts flexing as the body and car are pushed into the floor from downforce.
I have used normal tc bodies and fiberglass tape in the past, but thats just to make them last a bit longer, doesnt stop the flex or parachuting that can occur on the thinner body shells.

[Grogg]

On 10/05/2023 at 22:50, Redback said:

No I got a 2mm thick body for that exact reason, it doesnt need reinforcing its thick enough to take impacts and not flex under load.

The issue is stopping the body mounts flexing as the body and car are pushed into the floor from downforce.
I have used normal tc bodies and fiberglass tape in the past, but thats just to make them last a bit longer, doesnt stop the flex or parachuting that can occur on the thinner body shells.

Because of the TT-02 challenge I've got going with my mates, I've been reading up on and looking at body shells designed for speed runs, and they all tend to be 2mm thick, a few are 1.5mm thick, but the vast majority are 2mm thick.

 

Now I've recently bought extra body shells for my HPI Savage XL, official HPI ones, the 1979 Ford F150 shell, an extra stock shell that's been pre painted and stickered, and a clear stock shell - the stock shell is called the KingCrab, that you need to paint and sticker yourself.  All of these official HPI body shells are interestingly enough 3mm thick, 1mm thicker than the most used and common speed run shells, and the Savage XL is hardly designed with speed runs or high speed in mind.

 

I found that to be quite surprising.

[Redback]

Few parts inc, wider wheels, rear diffuser, will finish build this weekend 2 weeks till rossa first pass, no road shakedowns cant risk it.
Have to also put on the other 0 caster c hub as running a '6 and the spares arnt spares and are 0 caster pulls either side even double trimmed.
Want some spares for the event but mostly out of stock, fingers xd no crash maybe 150mph is a dream, now i see the chassis it seems long way off.

[Grogg]

15 minutes ago, Redback said:

Few parts inc, wider wheels, rear diffuser, will finish build this weekend 2 weeks till rossa first pass, no road shakedowns cant risk it.
Have to also put on the other 0 caster c hub as running a '6 and the spares arnt spares and are 0 caster pulls either side even double trimmed.
Want some spares for the event but mostly out of stock, fingers xd no crash maybe 150mph is a dream, now i see the chassis it seems long way off.

 

 

 Best of luck with R.O.S.S.A, I was hoping to attend this year but I've still got my Rock Socker to finish building - I'm pretty sure close to 50% of the members here have died of old age so far with how far along I've come with my Rock Socker build.  So I haven't even started on my 100mph TT-02 build - the other half of the membership will probably have died of old age by the time I get started on my TT-02 build.

Edited June 9, 2023 by Grogg