I want to start off by saying for once I was very sceptical with the changes with the new version of the FWD ARC the A10MF.
The reason for this is that the older A10mf had perfect side to side balance - I had less than 2 grams difference without adding weight to the car to get this right.
The new car is a little heavier out of the box on the motor side as the servo was moved to the motor side.
But I really did like the design of some of the new weights. I have wanted a lighter bumper weight on the A10MF and the new car does have the weight size I had suggested which is always really nice to see. I will get into how this all affected the car later in this review.
Let’s get into the building of the car.
Since this is an update, I will write more about the changes to the car and tips and tricks I have learned building this beast.
First up is the diff:
A tip here that I personally do is trim the edges of the gears and sand the backs of the gears flat with some 800grit wet/dry sandpaper and when assembling the diff, use some SIMSpec Red O-ring Jam on the O-rings to help prevent leaking and wear. This should give you a silky-smooth diff which with a FWD car is super important.
Another tip: measure the diff with a diff checker (if you have one) to keep track of the readings as FWDs can be hard on the diff and the fluid can become lighter with use.
The kit comes with 4 shims for each of the spider gears, I personally only used 3 on each gear as it felt a lot smoother which is super important with FWD cars.
Another thing I do is to use some paint on the eccentric hubs to make it super easy to see they that are in the same position.
Carbon Arms:
Pay attention to how they go together and glue the plastic bits once you have them all installed, to make sure they are all correct.
To help lower the risks of screws pulling through the chassis I use wider shims and my brass screws.
The Motor Mount:
A few tips with this one.
One is to run a 3.1 drill bit through the pin hole to help tweak in the chassis. If this hole is too tight it’s known to cause issues.
The manual says to install this on the chassis before installing the new single steering arm. I highly recommend doing this beforehand. It’s a lot easier.
Make sure you use a strong Loctite on the screw and grub screw. This is one part you do not want coming loose.
If you have any issues with getting it apart with the Loctite you can heat up the screws with a soldering iron first.
Top Deck:
This is another item I would install before doing other steps. To avoid having to bend and force the top deck to get underneath the fan mount, install the top deck first, then fan mount, then servo mount in this order.
Drive Shafts:
Make sure you install the black shafts and rebuild the units so you can add a high-quality grease. I use our Dinosaur goop on them for a long life.
When installing the completed knuckles onto the arms I use a drop of purple Loctite onto the grub screw to stop it coming undone with use. This was an issue I had with the other A10s as well.
So, let's talk about the new A10MF-24 X-Low Shocks and Springs:
Following the lead of Xray, Arc has new X-Low shock (7mm in length) shorter than the previous Ultra Short Shocks. They also allow the fitment of both ARC Ultra Short 20mm shock springs and the new X-Low 17mm springs.
I used all the normal tricks with building them. The main ones were to put a slot on the shock adjustment nut to make it easier to count turns, and used SIMSpec Red Jam o’ring grease to prevent leaks and air getting into the shocks.
Along with the new shocks, there are new shock towers that move the shocks down 6.2mm on the front and 6.5mm on the rear. This lowers the COG of the car a fair bit which is always a welcome advantage and should help improve corner speeds.
The new weights:
The kit comes with 4 weights; a 60g weight for in the bumper. This is down from the 85 grams in the A10mf which allows you to move the weight more in board, than having all the weight over the front of the chassis. I think this is one of the key improvements that I always wanted to test with the A10mf.
There are now custom shaped 35g weights that sit perfectly inside the front arms. The old 10g weights will still fit and have 2 mounting positions either on top of the 35g weights or to replace them.
The final new weight is the 25g weight that sits under the diff and again this is a tight fit and is machined perfectly. This weight was a feature I really liked about some other cars like the MTC2 and Xpress kits. So, it’s really nice to have this tuning feature now.
Upgrades used on this build were:
Stainless Steel Screws
Brass Screws
I don’t think anything else is actually needed. I will probably get the new white low friction belt to test to see if it will hold up with the 13.5t motors we run.
Electronics:
Hobbywing Juststock ESC*
Hobbywing Juststock 13.5t G2.1*
SRT 8015 Servo
Sanwa RX-482 Receiver
Sanwa MT44 Radio
Cheap 4900 Shorty Battery
*Class control itemsHow did the car perform, you ask?
First off, I would like to say I was 100000 percent wrong about this new car. It is fantastic out of the box.
I ran the car with the kit setup as I do with all my reviews.
I did a shake down run at Geelong at the end of a club meeting. Geelong is a very tricky track for FWD cars which normally, seeing as all cars have grip and balance issues and having to find tyre combos that work on the day.
The car felt really good. It was rather competitive straight out of the box (which was surprising) and I was able to come from last to 2nd place, and my lap times were rather competitive.
Now for the real test. I went to Boronia where I race every Wednesday night against two of the best FWD TCR racers in the country. To give a little background; of late Tim Boundy has been the front runner and been unstoppable.
In Practice I did a back-to-back comparison between the two cars and instantly I was blown away by the car balance and grip the new car produced. It had so much grip at both ends of the car and was .2 a lap quicker on its first lap!!!!
I felt the car was wanting more front grip as the rear was so locked in.
Through the night I tried many different tyre combos. Each run I was going to harder rear compounds and the car was still mega gripped up. Even in sub 10-degree track temps.
I was able to win all 4 races with the last race being the highlight. I felt really comfy running out the front pushing without worrying too much about Tim catching or passing.
I am not sure what is making the car feel so hooked up, but at this point I think it's due to the weight not being so far forward, but looking forward to trying some of these weights on the older car to see what is making the difference.
This platform I feel will only go from strength to strength and I look forward to the next few months tuning the car to see how fast I can make it.
I would like to thank ARC and Smokem for their continued support and getting me this kit to try.
There are photos and more tips on the Facebook post which can be found here:
https://www.facebook.com/SIMSpec/posts/pfbid02QaimMvcXdKqRjrVchmBtCoCBrN6465MfV8prgjwPwEkDHJkiCALzhd8hkj7uYVfZl