Restoration Project #8 - Huge Bundle of HPI, Kyosho and HSP.

[gandalfnz]

Awesome!

In my experience the stock servos worked, but not for long, and they get less reliable as they wear out. Basically good enough for break in, then replaced at the first rebuild.

I had one that would only glitch out while the engine was running, but seemed to work fine when tested. It would "wiggle" at full throttle, making me think I was having tuning issues.

I'm installing these locked, low-reduction diffs in one of mine now, to see if I can break 50mph with the VX-18View attachment 153075

Where did you get those from?
Interesting job that one, let us know what you get?
Does stiffer diffs means less cornering ability, never got into that diff thingy, maybe its time for me to learn.
I bet your Ffish is the most upgraded one out there. Good job!

 

[gandalfnz]

And....HSP is now at its full running capacity.....

 

[WickedFog]

And....HSP is now at its full running capacity.....

That is badass man. Sounds awesome.

 

[tudordewolf]

Where did you get those from?
Interesting job that one, let us know what you get?
Does stiffer diffs means less cornering ability, never got into that diff thingy, maybe its time for me to learn.
I bet your Ffish is the most upgraded one out there. Good job!

They're in this listing, which also has one-way diffs, more on those later...

Locked diff is a bit of a misnomer, as you can see, it's just a solid axle. All 4 wheels turn together. They were a bit stiff at first but wore in just fine. They're 40% "faster" than the stock diffs, gear-ratio wise.

With locked diffs front & rear, it drives... poorly. Very prone to sliding out, I only got it to 47mph before it would veer off to a side and spin out as I tried to re-center it. Definitely makes me appreciate what the diffs do for a car. I'll have to see if I can do anything to stabilize it, maybe with the alignment.

Stiffer diffs can reduce cornering, but they also distribute torque more evenly (also of particular value to crawlers), which can improve turning & stability at speed, provided they still provide some differential action. When a wheel spins out on an open diff, the opposite wheel also stops delivering power; the stiffness of the diff ensures that at least some torque still gets sent to the wheel that still has traction while the other one spins. This can happen due to low-grip surfaces, or the inside wheels of the car lifting up in a turn.

The VX 18 handled the increased resistance well, the new gear ratios are as if the car starts in 2nd gear and it had no problem getting it going.

Interestingly, the listing is proposing an even weirder setup- the idea is that you'd put the locked diff on the rear and a 1-way diff on the front to facilitate drifting, with a different ratio between the front and rear wheels. The rear wheels spin and push out the back, and the front ones would have no braking... I think it was intended for the electric / indoor drifting versions, but it adds yet another tuning option to the nitro.

 

[gandalfnz]

That is badass man. Sounds awesome.

Thanks.
This engine is super easy to tune.

 

[gandalfnz]

They're in this listing, which also has one-way diffs, more on those later...

Locked diff is a bit of a misnomer, as you can see, it's just a solid axle. All 4 wheels turn together. They were a bit stiff at first but wore in just fine. They're 40% "faster" than the stock diffs, gear-ratio wise.

With locked diffs front & rear, it drives... poorly. Very prone to sliding out, I only got it to 47mph before it would veer off to a side and spin out as I tried to re-center it. Definitely makes me appreciate what the diffs do for a car. I'll have to see if I can do anything to stabilize it, maybe with the alignment.

Stiffer diffs can reduce cornering, but they also distribute torque more evenly (also of particular value to crawlers), which can improve turning & stability at speed, provided they still provide some differential action. When a wheel spins out on an open diff, the opposite wheel also stops delivering power; the stiffness of the diff ensures that at least some torque still gets sent to the wheel that still has traction while the other one spins. This can happen due to low-grip surfaces, or the inside wheels of the car lifting up in a turn.

The VX 18 handled the increased resistance well, the new gear ratios are as if the car starts in 2nd gear and it had no problem getting it going.

Interestingly, the listing is proposing an even weirder setup- the idea is that you'd put the locked diff on the rear and a 1-way diff on the front to facilitate drifting, with a different ratio between the front and rear wheels. The rear wheels spin and push out the back, and the front ones would have no braking... I think it was intended for the electric / indoor drifting versions, but it adds yet another tuning option to the nitro.

When is the test drive?

I am having some issues with my FFish.
Today I had a crash into a curb, as the car just stopped steering, no big damange though, just a bit of scraping on that beautiful body
Upon inspection I found out that steering would stop working when you are using throttle at the same time, so naturally u suspected the servo.
Replaced it with this one...
https://www.aliexpress.com/item/1943129663.html?spm=a2g0o.order_list.0.0.21ef1802eUTIdP
Then, the problem remained, so I tried a FS BS6 receiver instead of traxxas with TSM that was in there initially since break in.
BS6 responded so much better, with servos working great, which I found odd. Thought that was it and off I went for a test run.
Now, I can't do a straight run anymore, car just skids out and I am afraid to give it more speed, no idea what is going on now.
Is it the servo, is it the receiver, was it the Traxxas TSM maybe which I had at 5% only? I have to figure this out, because it went straight like a bullet before, and to see it swirl like this is so disappointing.

I gotta feeling its the servo, as the same servo was on my mini cooper nitro, and I remember having exactly the same problem.
Bit odd, to find that stock crappy servo was so good at keeping the car straight.

I also tried playing around with steering exponential, but nothing changed.

Haha, a bit frustrated now, so gonna leave this for a few days then come back to it.

 

[gandalfnz]

So I reset the TQI RX and all seems to work on that end.
Also, thrown in Futaba 3004 as steering servo.

When I run the car it starts going straight, then steering just twitches to the side, I then have to apply brakes not to crash.
Never used to do this before crash.
The only thing to do is put back the old HSP stock servo and see what happens, but I doubt it will make a diff.
Maybe steering linkage took a hit when I crashed, but all seems to be normal and tight.
Damn it!

 

[tudordewolf]

So I reset the TQI RX and all seems to work on that end.
Also, thrown in Futaba 3004 as steering servo.

When I run the car it starts going straight, then steering just twitches to the side, I then have to apply brakes not to crash.
Never used to do this before crash.
The only thing to do is put back the old HSP stock servo and see what happens, but I doubt it will make a diff.
Maybe steering linkage took a hit when I crashed, but all seems to be normal and tight.
Damn it!

I had some steering issues with mine after a crash, turns out I'd slightly bent the linkages and given myself some toe-out, so that it'd "grab" in one direction or the other once it got up to speed. Pointing the front wheels back "in" helped me with that.

That's also why I put thicker grease in the front and rear diffs; I can't be certain this had the intended effect, but I think it did help to keep it stable at high speeds and under acceleration.

I use Radiolink TX/RX and haven't had any issues stem from it yet, and I like the gyro around 25%. I can't comment on TQi's effects.

I think the most important detail on the steering servo is a precise return-to-center; otherwise you'll constantly be over-compensating for the last control input you made and having a hard time setting the true center. Even some "nicer" servos weren't giving me good performance in that regard. I settled on the 4409MG and it's been rock-solid for me.

Starting to look like the end of the season around here, may have to wait 'till spring to do more bashing. Good chance to catch up on my backlog of maintenance and builds!

 

[gandalfnz]

I had some steering issues with mine after a crash, turns out I'd slightly bent the linkages and given myself some toe-out, so that it'd "grab" in one direction or the other once it got up to speed. Pointing the front wheels back "in" helped me with that.

That's also why I put thicker grease in the front and rear diffs; I can't be certain this had the intended effect, but I think it did help to keep it stable at high speeds and under acceleration.

I use Radiolink TX/RX and haven't had any issues stem from it yet, and I like the gyro around 25%. I can't comment on TQi's effects.

I think the most important detail on the steering servo is a precise return-to-center; otherwise you'll constantly be over-compensating for the last control input you made and having a hard time setting the true center. Even some "nicer" servos weren't giving me good performance in that regard. I settled on the 4409MG and it's been rock-solid for me.

Starting to look like the end of the season around here, may have to wait 'till spring to do more bashing. Good chance to catch up on my backlog of maintenance and builds!

That servo link is not working, would you mind fixing please?
I need to figure out why its twitching like that, almost makes me think tyres are not gripping on the concrete no more, but it can't be that cause it started doing this after the crash.

So, any toe in, or toe out would be bad for a car going straight?
Never paid too much attention to this, just made it approx straight, but a lot of cars I purchased all had toe out by quite a bit.
For me season has just started, beautiful spring weather.

 

[tudordewolf]

That servo link is not working, would you mind fixing please?
I need to figure out why its twitching like that, almost makes me think tyres are not gripping on the concrete no more, but it can't be that cause it started doing this after the crash.

So, any toe in, or toe out would be bad for a car going straight?
Never paid too much attention to this, just made it approx straight, but a lot of cars I purchased all had toe out by quite a bit.
For me season has just started, beautiful spring weather.

Fixed the link.

Toe out increases cornering / tendency to oversteer, making the car more prone to spin out.
Toe-in does the opposite, increasing stability and the car's tendency to straighten out under power / while sliding.

This applies to rear wheels too.

Good luck with the steering issue, it's gotta be something specific since you had it running well before.

 

[gandalfnz]

I noticed that there is significant toe out when braking, the whole linkage just sort of twists in a weird way and creates toe out.
So, as I default I have created toe in, so when braking wheels are straight.
Will see if this makes any difference, but again, before I didnt touch anything, and it just went straight haha

 

[gandalfnz]

Fixed the link.

Toe out increases cornering / tendency to oversteer, making the car more prone to spin out.
Toe-in does the opposite, increasing stability and the car's tendency to straighten out under power / while sliding.

This applies to rear wheels too.

Good luck with the steering issue, it's gotta be something specific since you had it running well before.

So I did some more testing yesterday, I seem to have fixed it, it goes straight like it used to before.
I think a bit of "toe in" adjustment did it?
Still not entirely convinced, will need to do a few more runs.

I have had a look at the brushless versions of this car, and there is one locally for sale.
All seem to be the "V1" of this model, and I was not able to spot the "pivot ball" suspension version?


Cheers

 

[tudordewolf]

I have had a look at the brushless versions of this car, and there is one locally for sale.
All seem to be the "V1" of this model, and I was not able to spot the "pivot ball" suspension version?

Interesting, the pivot ball revision may have only been done for the nitro model. Odd, considering they were all released at least 10 years.

Looking at their website, it seems they only made pivot ball nitros. A conversion is possible, and you'd get a pretty unique vehicle out of it.

 

[gandalfnz]

Hey

Would you mind linking again the web page with HSP manuals?
can't seem to find it, I know you posted it once.
I need a brushless version manual...
Do you see where I am going with this?

 

[tudordewolf]

Hey

Would you mind linking again the web page with HSP manuals?
can't seem to find it, I know you posted it once.
I need a brushless version manual...
Do you see where I am going with this?

Here you go

Looking forward to the build thread!

 

[gandalfnz]

Here you go

Looking forward to the build thread!

Hey thanks very much.
Car is actually in mint condition, I am picking it up tonight.
Scored it quite cheap.

Dont like the plastic chassis base!
Fun fact, this bundle (from the first post) came with an extra alu nitro chassis plate, which I threw in the rubbish, thought will never need it. It was a bit bent, but nothing some hammering couldnt have fixed.
Lesson learned, need to make some room in the attic.

 

[tudordewolf]

Dont like the plastic chassis base!

Yeah, fortunately there's aluminum ones available aftermarket, and in 5 colors, too. That's the listing for the car version, be aware that the buggy&truck version is longer and bent up at the front.

There's a subtle difference between the chassis for pivot ball and c-link versions; an extra hole for the diff cases of the c-link version which are completely "enclosed", the one superior feature of that version. Fortunately that means you only need to plug the hole to convert to pivot ball rather than drill it. If you don't, you can see the ring gear through the bottom of the chassis...

My solution was to put masking tape over the tops of the holes, flip the chassis upside-down, and pour some epoxy into them - I used jb weld and also slightly roughed up the edges it would be touching to make sure it got a good grip. The making tape came off easily and left a flat surface.

 

[gandalfnz]

Yeah, fortunately there's aluminum ones available aftermarket, and in 5 colors, too. That's the listing for the car version, be aware that the buggy&truck version is longer and bent up at the front.

There's a subtle difference between the chassis for pivot ball and c-link versions; an extra hole for the diff cases of the c-link version which are completely "enclosed", the one superior feature of that version. Fortunately that means you only need to plug the hole to convert to pivot ball rather than drill it. If you don't, you can see the ring gear through the bottom of the chassis...

My solution was to put masking tape over the tops of the holes, flip the chassis upside-down, and pour some epoxy into them - I used jb weld and also slightly roughed up the edges it would be touching to make sure it got a good grip. The making tape came off easily and left a flat surface.

Thanks for the feedback!
So, I need to put together a list of parts for the pivot ball conversion and see how much it will cost me in the end.
Might be able to source a run down version of the car, with all the extra parts for less, maybe.

I need front and back A arms, alu chassis is optional, anything else?

Cheers

 

[tudordewolf]

I need to put together a list of parts for the pivot ball conversion

If there's any way you can avoid that, it's a massive pain. I tried to do that myself for my TRX 3.3 swapped monster truck, and that's why I haven't finished it yet. I would recommend straight up breaking down a nitro roller for the front + rear assemblies and calling the rest extras for your nitro.

I've had to place multiple extra orders to finish my parts list and I'm still not sure I have every little bit.

You'll also need different suspension pins, basically a whole set, new diff cases, new drive cups, (or CVD's if you want), lower rear arm & upper rear linkage, "fixing block" 06055...

On the plus side the front and rear diff housings are identical, not sure why they listed them twice. Good chance to buy the aluminum cases instead, with the right shims they turn butter-smooth. I recommend 10mm x 0.5mm opposite the ring gear on the diff, .3mm up against it, behind the bearings.

 

[gandalfnz]

I hear you....
Had a few projects like this myself in the past, and yes, they are very time consuming and expensive to complete.

I wonder, how hard would it be to convert the nitro version to electric, would that be an easier route.
Removing the transmission and engine, and mounting the motor...etc.