HSP 94122 suspention

[dan_man5000]

Hello again 94122 people, I'm thinking about upgrading my HSP 94122 suspension to better suit off road driving (just dirt road driving not anything crazy).
And i'm wondering what parts I would need, speciffically to get it off the ground more as it sits verrrry low from factory.

I have already bought some overkill wheels: these ones. Pretty sure i will need to change the gearing? if so how do I do that properly? realised I also need to cut the foam at the front so they fit
will it be worth it? if not what should i get instead?

Edit: also thinking about a proper battery instead of using AA's. what battery/charger should i go for (can solder) and will I need new servos?
I'm thinking about this one. will I need new servos?

Sorry for all the questions, Any help is much appreciated. Cheers

 

[tudordewolf]

Hey! I've had the same thought since mine was getting scratched up just by pebbles and cracks in a parking lot, not even taking it off road.

One of the simplest things I did was bend the tabs on the chassis that limit the suspension arm movement about 20° down, by clamping a pair of vice grips over the tab. This added a lot of clearance just on the stock wheels:

The problem you're going to run into with those wheels you've linked is their width. About the largest wheels you'll be able to fit on a 94122 are these, but the upshot is that you'll only have to cut the bumper foam and otherwise they'll drop right in. They're 75mm, so a good bit larger than the stock ones. With those and the bent tabs you should have some substantial clearance.

The other HSP models (94155, -66, -77) are built of almost all the same parts, just longer suspension arms & chassis, and use wheels like the ones you linked. They're also geared lower, so you could use the transmission from them (42/47 gearing), to compensate for the bigger tires and the added resistance of going off-road.

My experience though, is that even with heavily modified gearing, the 2-speed is going to struggle with the added resistance, and winds up bogging the engine down just as it hits the powerband in first gear.

Maybe it would be ok over packed dirt, but the wheels kick a lot of dust & dirt into the body shell, and into the air filter, especially because they "break free" and spin more easily. The issue isn't as bad on the other models because they have larger, looser body shells with space around the wheels, or are entirely open-wheel with the shell protecting the air filter.

 

[dan_man5000]

Hey! I've had the same thought since mine was getting scratched up just by pebbles and cracks in a parking lot, not even taking it off road.

One of the simplest things I did was bend the tabs on the chassis that limit the suspension arm movement about 20° down, by clamping a pair of vice grips over the tab. This added a lot of clearance just on the stock wheels:

View attachment 179209

The problem you're going to run into with those wheels you've linked is their width. About the largest wheels you'll be able to fit on a 94122 are these, but the upshot is that you'll only have to cut the bumper foam and otherwise they'll drop right in. They're 75mm, so a good bit larger than the stock ones. With those and the bent tabs you should have some substantial clearance.

The other HSP models (94155, -66, -77) are built of almost all the same parts, just longer suspension arms & chassis, and use wheels like the ones you linked. They're also geared lower, so you could use the transmission from them (42/47 gearing), to compensate for the bigger tires and the added resistance of going off-road.

My experience though, is that even with heavily modified gearing, the 2-speed is going to struggle with the added resistance, and winds up bogging the engine down just as it hits the powerband in first gear.

Maybe it would be ok over packed dirt, but the wheels kick a lot of dust & dirt into the body shell, and into the air filter, especially because they "break free" and spin more easily. The issue isn't as bad on the other models because they have larger, looser body shells with space around the wheels, or are entirely open-wheel with the shell protecting the air filter.

Thanks mate ill buy those wheels now and try to bend the tabs. I also wanna get some metal suspension components.
Do you have any ideas for the battery/servo? Will the battery linked above be ok soldered to the wire on the standared AA battery pack so it fits? also will i need a new servo with that one?

 

[tudordewolf]

Thanks mate ill buy those wheels now and try to bend the tabs. I also wanna get some metal suspension components.
Do you have any ideas for the battery/servo? Will the battery linked above be ok soldered to the wire on the standared AA battery pack so it fits? also will i need a new servo with that one?

That battery wouldn't fit in the tray, and if you go for 2S, 7.4V, you'll need "HV" servos, which are a bit pricier.

My suggestion is a 1600mah NiMh "hump pack" - it'll deliver better performance than the AA's you have now, with the same servos. It's what I use. This combo would cover you for both battery and charger, though you would have to change the connector since it's got a "servo port" style plug. I myself change the connector on the car to the kind instead of the other way around. You can crimp those instead of having to solder them, the kit & tools for it come in handy all the time once you have them.

 

[dan_man5000]

Thanks again mate I’ll have a look into it.
Where would I buy the plug (in this case “servo port” style plug) to crimp or solder to the car?

 

[tudordewolf]

Thanks again mate I’ll have a look into it.
Where would I buy the plug (in this case “servo port” style plug) to crimp or solder to the car?

This kit should be perfect, it even gives you the option to use either kind of connector. It takes a little practice to get the technique down, you might want to do a few scrap wires first before you start clipping down wires you'll need.

 

[dan_man5000]

Hey Tudor, thanks for your prevous reply but sorry, I have another question. How long do these vx-18 engines last in the 94122?
I feel like I've just lost compression, it wont start even with a new glow plug. Just charging my electric starter and igniter now hoping that could be the issue. although I dont feel much compression.

Do these electric starters wear out the engine? its what I use.
Its a very new car, only been started about 10-20 times since run in...

 

[tudordewolf]

Hey Tudor, thanks for your prevous reply but sorry, I have another question. How long do these vx-18 engines last in the 94122?
I feel like I've just lost compression, it wont start even with a new glow plug. Just charging my electric starter and igniter now hoping that could be the issue. although I dont feel much compression.

Do these electric starters wear out the engine? its what I use.
Its a very new car, only been started about 10-20 times since run in...

It shouldn't be dead just yet, you should be able to put at least a few gallons of fuel through it before it starts losing performance. The first one I ever bought, which I made plenty of mistakes with, even running it too lean until it stalled from overheating, still runs fine.

Unless something specific happened like dust getting past the air filter and scratching up the piston, but that would take an extreme case and you'd know by The sound and feel when you turned the engine.

It sounds like you're getting past the break-in and the engine is starting to "open up" - they get a lot easier to start after the first few times, but the tune will change on you too. You might need to richen up the low-speed needle or open up the idle gap a little and set it again once you get the engine started.

I think you're fine with an electric starter. There's the risk that if you flood the engine, the force of the starter can break something, but that's rare and avoidable with a little caution.

 

[dan_man5000]

Thanks so much mate your a life saver, I’ll play around with it later, pistons still moves up and down so should be good!

It shouldn't be dead just yet, you should be able to put at least a few gallons of fuel through it before it starts losing performance. The first one I ever bought, which I made plenty of mistakes with, even running it too lean until it stalled from overheating, still runs fine.

Unless something specific happened like dust getting past the air filter and scratching up the piston, but that would take an extreme case and you'd know by The sound and feel when you turned the engine.

It sounds like you're getting past the break-in and the engine is starting to "open up" - they get a lot easier to start after the first few times, but the tune will change on you too. You might need to richen up the low-speed needle or open up the idle gap a little and set it again once you get the engine started.

I think you're fine with an electric starter. There's the risk that if you flood the engine, the force of the starter can break something, but that's rare and avoidable with a little caution.

 

[dan_man5000]

Alrighty it works. I had to adjust the low speed needle quite a bit and now it’s smoother than ever!

But…
One more issue, not a big one just the throttle is stuck. Probably less than a quarter, the car still brakes and stops fine, just when I’m not on the throttle it moves.
I’m wondering if the carb could be dirty? Or maybe it’s normal I can’t remember if it moved without throttle before.

Thanks!

 

[tudordewolf]

Alrighty it works. I had to adjust the low speed needle quite a bit and now it’s smoother than ever!

But…
One more issue, not a big one just the throttle is stuck. Probably less than a quarter, the car still brakes and stops fine, just when I’m not on the throttle it moves.
I’m wondering if the carb could be dirty? Or maybe it’s normal I can’t remember if it moved without throttle before.

Thanks!

Awesome!

You might need to adjust the endpoints on the throttle linkage so that the spring is lightly pressing against the carb when it closes,, or adjust throttle trim on the transmitter so that it holds the servo in the "idle" position and not slightly up on the throttle

 

[dan_man5000]

Hey mate, so I've done some modifications..., (new fuel tank with metal cap, full metal exhaust system + gasket, fuel filter, air filter that seems to fit very loosly, and the wheels you linked above which fit great btw). But the car won't start. I have noticed there is a leak between the new fuel cap and tank when i turn the car upside down, is that normal?
Anyways, it doesn't look like any fuel is entering the engine. i have a thinner fuel line (3x5x1m) connecting the tank to the filter, with the the factory line connecting the filter to the engine, would that be a problem? The glow plug works fine.

Thank you!

 

[tudordewolf]

Hey mate, so I've done some modifications..., (new fuel tank with metal cap, full metal exhaust system + gasket, fuel filter, air filter that seems to fit very loosly, and the wheels you linked above which fit great btw). But the car won't start. I have noticed there is a leak between the new fuel cap and tank when i turn the car upside down, is that normal?
Anyways, it doesn't look like any fuel is entering the engine. i have a thinner fuel line (3x5x1m) connecting the tank to the filter, with the the factory line connecting the filter to the engine, would that be a problem? The glow plug works fine.

Thank you!

That leak is definitely not helping, it should seal. I've found the o-ring can get pushed out of the groove when it's dry, you might want to remove it, smear a tiny bit of o-ring safe grease on the entire thing, and replace it, to make sure it seats correctly. I'd also use the original, stock orange o-ring on the new cap rather than the stiffer black one they include with the aluminum cap

The fuel line shouldn't be an issue, but I might try it without the fuel filter to see if that helps.