SG 1603 / SG 1604 Review and THe Simple Fixes That are critical

The SG 1603, SG 1604 and UDIRC 1601 are small 1/16 scale 4wd on road cars designed for skids on any smoothish surface. They are extremely durable and the edgy body shells (SG 1603 Hoonitruck/Infraction and SG 1604 Moke) being the only thing that separates these two. Here I've reviewed the SG 1604 Moke and have written a setup guide on how to greatly improve performance by fixing the errors out of the factory

Before I start this review I'll note that this car from "SG" is supposedly the same company that made the SG 1601 and SG 1602 4wd 1/16 brushless truck which won my budget RC basher of the year award for 2020 here. In addition my review and follow up can be found here and here. Thus is was with great expectation that I have reviewed this car.

What's included?

• The car itself (brushed 380 powered 4wd 1/16 scale onroad chassis)
• 2.4GHz transmitter with gyro control
• Stylish pre-painted PC body with plastic detail and functional 3 stage headlights
• Onroad preglued tyres and rims fitted (white wheels)
• Drift tyres and rim (black wheels)
• 2s 1200mah li-ion battery (mine came with 2)
• USB balance charger
• Wheel nut removal tool, screw driver and hex tool
• 2 x spare linkages
• A surpsringly comprehensive user manual

A closer look at the car - Drivetrain
The car is powered by a 2s lipo with lightweight JST connector to an all in one receiver/ESC unit which is typical of lower priced RTR models. This powers a brushed 380 motor which drives a 4wd system via 16t 0.7m pinion to a 38t spur gear and full time 4wd drive train. My drive train had a lot of bind from the factory but I was able to fix in my setup guide as below - in short reducing the rear travel. This car uses metal driveshafts - CVDs on the front and dogbones in the rear which is good news. There are ball bearings on all moving parts in the drivetrain to help keep friction down and improve durability. Diffs are plastic and contain only one pair of planet gears meaning that they would not be well suited to a larger motor (including brushless).

A closer look at the car - Steering
Steering starts with a 5 wire micro servo which is plenty fast in this application. The steering system is lightweight, basic and effective. There is no adjustment which is fine because linkages appear to be exactly the right length and 2 spares are included with the car. Servo saver is basic but again effective. All of this makes for a fairly fast and well centred steering system which is well suited to a skid/drift car like this.

This car is set up with a gyro in the receiver and control via the transmitter which essentially gives you access to adding some countersteer in but try as I might I couldn't see it working as I did with the gyro on my FS-GT5 transmitter (as seen on this page) nor could I feel it. Perhaps mine was faulty but the way this car was balance I didn't really miss it.

A closer look at the car - Suspension
All upper arm linkages are fixed plastic items meaning you have non-adjustable camber which is fine since they are well sized. Good news that they seem to be made of the same plastic as the SG 1601 and SG 1602 meaning they absorb impact easily without getting bent or broken.

​Shock absorbers are mostly there for display. They are NOT oil dampened and are too long front and rear (50mm and 55mm respectively). This means they body sits higher than ideal and so looks a little lame but more importantly it causes the rear drive shafts to rub, causing a lot of friction in the drive line. A a crucial change in my setup guide below I did fix this however which greatly improved ride height - better looking, better handling and a much more efficient driveline. Although oil fill shocks would have been nice, It's probably unnecessary on they type of surfaces you are likely to run this car on.

55mm at the rear (too long for this car)

50mm for the front (also too long)

A closer look at the car - Transmitter
Transmitter was fine, there is no control over throttle parameters, not that they are needed here. You have steering trim adjustment of course, steering dual rate to adjust the amount of steering throw you have and of course a potentiometer for controlling the level of countersteer intervention (labelled ESP here). In terms of range I never had an issue with what I'd expect for a 1/16 scale brushed road car where I'd never expect to drive too far from myself.

There are also another 2 channels that give you a lot of control over the lights - more on that in the body and headlight section below

A closer look at the car - Body and headlights.
Whether the Moke styled SG 1604 or the Hoonitruck/infraction styled 1603 let's face it - the body is one of the main reasons you are probably considering this. They really don't disappoint in fit and finish - they look fantastic, with multiple plastic inserts giving them a really detailed look that you cannot achieve with polycarbonate alone. Speaking of the polycarbonate body, it is nice and thick and fits PERFECTLY with the rear plastic and front foam reinforced bumper - this makes it super durable so that it can hold it's shape and functionality in repeated crashes and this is covered more in the review just a little further down.

I never knew how much I like headlights until I had this car but these are special. A push button switch where your thumb sits allows you to turn the headlights on an off. Another 3 position switch just above your thumb allows you to choose a red halo "angel eye" light, a while projector style light in the centre of the halo or both. Check out the videos in the review just below.

So what - how does it run?!
As I've mentioned out of the box this car definitely needs some simple adjustments as below so I've completed my review based on this adjusted state.

This little car is a lot of fun. Weight bias is fairly even front to rear meaning breaking into a power-slide or skid when getting on or off the power is easy and predictable even though it does only have basic non-dampened suspension. Because of it's small size, compact design and responsive steering it feels a lot faster than it is, ultimately the 380 brushed motor provides good power for the type of driving whilst being light and providing the all important balance that a skid car needs.

It's nice that they have included a dedicated set of hard drift wheels as well but I ultimately think the white grip wheels are better and the car has enough power to get into a slide even on coarse concrete as seen in the video below.

As mentioned earlier the body fit to the car is excellent and the dense foam padded bumper (which follows the body contour) makes it super durable. Small overhangs front and rear means you are less likely to catch on obstacles and do damage.

Front of the body fits very cleanly against the contoured foam bumper making it extremely resistant to knock and bumps

My pictures don't do it justice but the combination of polycarbonate and moulded plastic make the body very detailed.

I really do need to mention the lights. Let's face it, they are gimmicky but so much fun and really this is what this little car is all about. Check out the amount of control you have on them below. One channel with a 3 position switch allows you to flip between either the red halo, white projector beam or both while another channel allows you to turn them on or off altogether. See more in the videos below

Headlight on/off control

Switch headlight mode control

Interestingly this car comes with gyro stability correction which essentially adds counter-steer to assist you when the car gets out of control much like the Flysky FS-GT5 and DumboRC radio gear sets. Unfortunately on my model I couldn't get this working. It's not a big deal but would have been nice only really low friction surfaces with the plastic drift wheels

Gyro countersteer control is labelled here as ESP. I haven't got it working but will update if I do.

The driveline on the car is durable where it needs to be: Rear dogbones, cups and front CVD driveshafts are metal as well as the main driveshaft. Diffs are fine for the stock brushed motor but being plastic with plastic cups and a single pair of plastic planet gears means that an upgrade to brushless will probably be too much for this little car. Pinion gears is made of brass and uses a grub screw which is good.

Metal CVDs in the front 👌

Metal dogbones and outdrives in the rear

Diffs are fine for stock motor but will struggle with a brushless upgrade

Ball bearings everywhere and 0.7mod 16t pinion and 38t spur

OK so it's clear this is a fun little car but after a fair bit of work put into the design to make it right, the execution was poor, particularly the suspension. Luckily the fixes are simple and cost little to nothing.

Setup Guide - fixing the suspension
If you do nothing else then please fix this. It seems that the front and rear suspension is a little too long and this has 3 negative effects, worst of which is last:

• Looks crap - these cars look best LOW
• Handles poorly - less predicable and skittish
• In the rear it over extends the driveshafts and causes the driveline to bind

I can't put too much emphasis on what a problem the last point is - a serious problem. It took a lot of troubleshooting and pulling the car apart to fins that an over extension of the rear suspension (and a little in the front) is the cause of the drive line binding really badly - you could tell before even driving the car that this was causing issues with overheating, poor performance and shortened battery life. It's good then that the fix is easy, check out the steps below:

Stock rear shock absorbers are too long

I used a 5mm long plastic spacer with 3mm hole which was perfect but you could use 2 x m3 nylon nuts too

One of the rear shock which are easily disassembled with the spacer at the top of the piston. Reassemble and reinstall

Stock front shock absorbers are also too long

In the front I used an m3 nylon nut as the spacer

Front shock disassembled with the spacer in place

Car with no suspension spacer looks jacked up and this photo is flattering

Stance is much better now - low, flat, even and no rubbing on the body.

I recommend using the spacers to the right for this job, I just used what I had lying around. These spacers are about $1 for 50 which is more than enough to fine tune the height to your own liking​ Suleve™ MXNW3 100pcs M2 M3 M4 M5 Black Nylon Washer Gasket Thickness 1mm - M3

With this reduction in height it looks and handles better but most importantly it frees up the driveline to be much smoother with more power and better efficiency (longer battery life). If you do nothing else to this car, please make this change as it makes a world of difference to performance and ultimately enjoyment

Setup guide - greasing and adjusting the diffs
This part isn't as critical and is a little more complicated if you've never delved into an RC car before but it will give more life to your diffs (which look to be the weak point in the drive train). Further more the diffs are over-tightened from the factory so this is a good chance to loosen them off a little. Follow the images and instructions below to complete.

Firstly remove the top deck in order to access the front and rear diff housings. You don't need to clip the zip ties holding the wires down

Remove the rear diff housing and note the diff drive spur on the left side. Unclipping the shocks and removing the camber arms makes this much easier 

Undo the 4 screws on the diff to expose the plant gears. No need to remove them

Load the diff up with the thickest grease you can find. I used heavy duty bearing grease

Grease will squeeze out of the screw holes when you replace the drive spur. this is good. Tighten all 4 screws right up and the back off a turn. Make sure the diff is not binding - loosen or tighten to make sure the diff is not notchy but has resistance from the grease

Repeat for the front diff. Note the side the drive spur is on again when reassembling.

Future upgrade: Improve the battery connector
The connector used to link the battery to the ESC is a JST and is only capable of delivering a constant 5A. Since the peak draw is likely to be above this (20-30A I'm guessing) then this will create a significant voltage drop and will pass less power. The practical result is that the ESC will move to limp mode before needed - in my testing the ESC low voltage cutoff is conservative ( a good thing) but the big voltage drop means that it starts to limp when the cells are at connector which is better suited to this current draw and doesn't really sacrifice on bulk. Also since the charge uses the balance port you'll have not compatibility issues either. I'm not expecting changes to be significant so won't  bother recommending now but if I find them to be worthwhile, I'll update things here.

The stock JST battery connectors can only manager about 5a continuous

XT30 connectors can handle 30a continuous easily and are a lot more durable over repeated matings. I'll report back if they have a real world benefit

Recommendations
This car is poorly setup (but easily fixed as above), has low quality suspension and limited adjustability. Oh and it's relatively slow too. So why to I recommend it??? Well, simply put, it's fun. There is enough power to make this skid, donut, powerslide and if you have the skills, drift. Weight balance is ideal for this style of driving and the combination of this, size, total weight and tyre choice makes it a real blast. Importantly it looks the part to with the Edgy Moke design in the SG 1604 reviewed here or the Hoonitruck/infraction look of the SG 1603 and UDIRC 1601. The awesome remote adjusted headlights add to the look too - a gimmick of course but a very fun gimmick.

​If you are feeling a bit exhausted from maintaining more expensive cars and just want to get back to some no-strings fun or have a young person that needs something durable and reliable that can take a good hit then this is a good, inexpensive option and worth trying out. Both the SG 1603 and SG 1604 are available from Banggood and ship worldwide. Update, the UDIRC 1601 is also the same car if the others are out of stock

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SG 1604 RTR 1/16 2.4G 4WD 30km/h RC Car 

SG 1603 RTR 1/16 2.4G 4WD 30km/h RC Car

UDIRC 1601 RTR 1/16 2.4G 4WD 30km/h RC Car

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