Vintage Top Force Evo Refresh

[Mad Ax 9312]

This is my vintage Top Force Evo, bought back in 2017 from a friend as a much-loved runner and survivor from the early 90s racing scene, this car got a quick refresh and new body and became my go-to chassis for vintage racing.  It's done me proud for the last 4 years at the Iconic Revival, this year I was planning on giving it a break and running a modified Hotshot instead, as the TF is in need of some love, but the 2021 Revival is massively over-subscribed and the Hotshot class was fully booked, so I was lucky to scrape an entry into the early 90s class.  My entry confirmation arrived on Saturday, so Sunday seemed the perfect day to drag the TFE off the shelf and give it a refresh.

I've never fully documented it on TC, so here's a recap from the start - including as much as I know about the car from the person I bought it from.

This is how it came to me in March 2017 - a wearing Top Force Evo body, Evo shock towers and modern alloy shocks.

You may also spy a few alloy hop-ups and the rare white arms, lurking under the front gear case is a front one-way and under the body is what I believe to be a HPI chassis.

The included electrics were no good to me as I race with LiPos and didn't have a Tx compatible with the old receiver, so it was stripped out and fitted with one of my older brushless systems and a Spektrum-compatible ORX receiver.

Here we see it one month later, stripped of body and fitted with brushless power, and wearing some ancient Manta Ray wheels so I could test it on the tarmac without destroying my Schumacher race tyres.

The car had a full strip, clean and rebuild.  Some of the bearings were completely seized, some were loose and floppy, one wasn't even the right size and had been spinning freely on the prop drive for who knew how long.  It ran well enough on the tarmac but I would need to wait until the Revival to see how well it went on track.

First, it got a fresh coat of paint on a repro body.  Here it is post-paint, sitting alongside my Buggy Champ, which would be my entry for the 2wd race.

And finally - the fleet, ready to be boxed and loaded.  Top Force Evo, Manta Ray spares car, King Blackfoot for the monster truck race, Wild Mini for the wheelie race, Rough Rider for 2wd race day and vintage SRB custom lightweight conversion as a spare car.  This was Thursday 27th July, 2017, one day before I prepared to leave and 3 days before the Evo would have its first proper run on track.

[Mad Ax 9312]

Everything boxed and loaded, along with awning, sleeping back, and a fridge full of food and cider.  The Revival is the one event of the year when I clean my camper inside and out.

A day later and the sun is shining.  It wouldn't last.  7:30am, 2wd race day, A1 Racing Club, Grantham.

This was my view of Saturday's endurance race:

Well, I digress - and the story of the SRB is one for another day.  How did the Evo go?

Practice went well.  The Revival is a busy day with a tight schedule, so one practice session is all you get before racing starts.  The Evo handled brilliantly.  I've been so accustomed to running older cars that can't keep pace with modern tracks, that I wasn't prepared for the revelation that was a not-entirely-badly set up Top Force Evo.  It went pretty much were I pointed it.

For race 1, I dropped the car on track and pulled the trigger to get it to the line, whereupon it made a screeching sound and didn't move.  Well, that was a problem!  The pinion wasn't mounted entirely correctly and the spur had stripped.  So, abort race 1, back to the pits for a rapid cannibalisation of the Manta Ray.

Race 2 was better, IIRC in race 3 I broke the front shock tower mount - it was already looking fairly well battered and the screws pulled out during the race.  Ace of Axe frontman and all-round nice guy Scott had brought a spare re-re Top Force NIB, into which he kindly dug to furnish me with the part I needed.  Result!

The rain came in midway through the day and in typical bad-planning fashion, I hadn't brought any wet tyres with me (partly because I'm forgetful but mostly because I didn't actually own any).  The pit shop didn't have any either (I can't remember who it was then but two years later we got Racecraft RC who are always well-stocked :p ) so I was struggling for grip into the finals.  In fairness I was also struggling with my complete lack of talent, but I managed to convert it into a win in the D Final.  A 1st place trophy is always good, but in fairness that did make me effectively 31st out of 37 in class.  Another weekend and the highlight of the RC calendar was done and I was heading home with a very soggy Top Force Evo to clean.

[Mad Ax 9312]

[Mad Ax 9312]

At this point my pictures run dry for quite some time, but the Evo remained in use for several more Revivals and the odd one-off vintage race here and there.

I digress a little for a while, as I reminisce about Revivals gone past.

Revival 2018 will always be remembered as the Disasterval, at least by me.  We'd had a heatwave, temps up around 31* C for a week.  That won't scare people from warmer climes, but for us Brits it's about as hot as it gets and we're not built for it.  I arrived at A1 Racing Club a little after midday with the aircon running full blast, I wound down the window to be directed to my camping spot and was suffocated by a wall of humid heat.  I put up my awning wearing nothing but shorts and sandals while the temperature rose above 30, and experienced the rare sensation of sweat running down the backs of my knees.  No sooner was the awning up did the winds roll in and temperatures plummet.  I was parked at the back of the site, under a bank, and the wind coming across the fields was directed upwards by the bank, over the roof of the van and right into the awning flap, inflating it like a balloon.  Testament to Vango, the awning wasn't damaged but the constant flapping put scratches down the side of the van.

Then the rain came, too.  A blessing in disguise, as I was still sticky with sweat and had no access to a shower before 2 days of racing and a 200 mile drive home, I stood outside with a teatowel and some emergency spare shower gel and scraped off the grime.

It wasn't my last shower of the weekend, as the rain didn't really stop for long and the top of the awning would form a reservoir that I could have used to power an indoor shower.  In fact I frequently got one, when the wind blew and the flap lifted away from the van roof and all the water came in.  It was a fairly soggy affair.

This was about as good as my view got.  Toy cars and alcoholic beverages - this is what the Revival is about.

Venturing outside during a lull in the rain.  See the gate behind the maroon car in the distance?  This will become important later in the story.

Friends.  This picture was taken back when we were still allowed to have friends.  Also toy cars, alcoholic beverages and fried food.

Fried.  Food.

Toy cars and Jack.  The Racer's Cocktail.

Fried food, toy cars.

Friend.  Toy cars.  Alcoholic bevarages.

Toy cars.  Rain.

No rain!

[Mad Ax 9312]

In fairness, the start of Saturday wasn't too bad.  I was racing a Bear Hawk and it was about as good as can be expected when one considers the cars it was up against, but this story isn't about the Bear Hawk.  Ostensibly it's about the Top Force Evo, but this particular chapter is about the phonecall I took from my wife around midday.

Apparently she'd been up all night feeling unwell.  We didn't think much of it, hoping it would pass, but she was exhausted and managed to palm our daughter (who was only 18 months old then) off to a friend so she could have a rest.  Well, no matter.  Admittedly I hadn't been feeling brilliant all week, but then I have a long-term condition so I thought nothing of it.

Sunday came and I got on track with the Top Force.  There was no pit shop at all in 2018, so no wet tyres.  And it rained.  Hard.  All day.  So hard that a lot of folks went home, or didn't turn up.

I got another call from the wife to say she'd had a bad turn, had packed our daughter with a friend and was being taken to hospital, and could I come home?  Well, back to that picture with the maroon car.  The gate behind it was the exit.  Between it and my van were cars, tents and caravans.  By that time on Sunday there were a lot more cars, tents and caravans.  So, no, I couldn't come home.  I was pretty much stuck until everyone between me and the gate had gone home.  Plus I had friends who had brought their pit tables into my awning because their shelters had been destroyed by the wind, and if I left, they would be out in the rain again.

Then I started to feel unwell.  I missed my final qualifier because I was camping out in the porto.  Fortunately I'd been wise enough to bring my own, so at least I wasn't holding up the line, but it wasn't the nicest place to be while in the throes of a Norovirus infection.  (Actually I didn't know it was Noro at the time, it was only when my wife got her positive test in hospital the next day that it became clear).

I managed to get back onto the grid for the final, having qualified in 2nd place in the B (IIRC, I don't have the heat sheets for that event).  B sounds like a massive improvement, but due to reduced numbers there were only 2 finals for the class in 2018 and only 6 cars in the B.  I had a really good start, took the lead by the first corner, got plenty of distance and held it for over a lap before - aargh - timing system failure!  So we were called back for a restart.  It's frustrating to be in the lead and lose it because you make a mistake, but even more so to have made a massive lead and lost it because the timing system went down.  But, hey, these things happen.  We lined up again, got underway, and this time I had a terrible start.  At the time I blamed red mist, but I just couldn't stay on track.  Every corner I went off again.  I managed 3 laps before the Evo veered off the main straight and went nose-first into a barrel with a noise that drew an "oooh!" from the crowd.  Fortunately no damage was done, but my race was over.  In a rare fit of race rage (most likely brought on by viral fatigue and stress that my wife was in hospital and my baby stranded at a friend's house) I stormed off the podium, collected the Evo and went back to the pits.

In the pits I found the culprit.  The left lower kingpin had taken a leave of absence and left me with a floppy hub.  Well, it was no wonder it wouldn't go straight, and would have cost me my lead eventually if the race hadn't been restarted.  So it was my fault all along!

At least I had a headstart on packing up, and I managed to get away in short order once the rest of the cars and tents were gone.  A little over three hours after setting off I pulled up at home to find my friend sitting on my sofa, recording his podcast while my baby slept upstairs.  He was dutifully thanked for his services and paid with a Chinese takeaway before he headed off, leaving me to reflect on what had been a tough and, in all honesty, absolutely flippin' brilliant Revival.

[Mad Ax 9312]

For 2019 the Revival moved to Bingham Model Raceway in Saxondale, and at last I started taking it seriously and bought some wet tyres.  Which was just as well, because, well, it rained.  It rained so hard the organiser's awning welled up enough water on its roof that it collapsed under the weight.  There's less to say about this event, other than that I took no photos and have no anecdotes to share, and I managed 2nd place in the C final.

There is another Top Force-related anecdote from 2019, involving the new Dirt 3D track local to me.  On 23rd September they hosted a Festival race, during what should have been a local festival which was cancelled due to, you guessed it, rain.  But we come from the Westcountry and we're not made of salt, so we turned up anyway and went racing.

Those of you not from England might begin to get the impression that it always rains here.  And, well, largely you're right.  We have a saying here - if you can see those hills it's going to rain, and if you can't see those hills it's already raining.  There are basically two weathers: raining, and not raining yet.

I don't have many photos of the actual racing because I didn't have a waterproof camera, but here's a pic of an SCT:

I don't have any of the Top Force because I couldn't find it under all the mud.

Anyway, I raced real hard all day, got 2nd place in all my heats and therefore qualified 2nd overall, which I managed to convert into a 2nd place win in both finals.  Which sounds very impressive until I point out there were only 2 of us in the heat and the other driver was Adie from Racecraft RC, who can hustle a Manta Ray on the dirt as well as anyone.

At the end of the first final, my car slowed right down.  I wasn't sure if it was heat, jammed gears or battery failure, but I soldiered on to take the line because, well, there was a trophy up for grabs.  After the race I unfastened the battery straps to change packs and the battery pretty much ejected itself.

Figuring the pack was past its best, I threw in another identical pack and went out for final 2.  And the exact same thing happened.  Evidently my gearing wasn't right for heavy mud, and I was pulling too many amps through the batteries.

But all's well that ends well, and I came home with a rather special trophy, from which I duly drank a celebratory beverage with a home-cooked meal.

 

[Mad Ax 9312]

Of course the next event on the Top Force Evo's calendar would be Revival 2020, which almost never happened and finally got going in early September, during what we were all hoping was the end of the pandemic and now appears to have been the eye of the storm.  Speaking of storms, it didn't rain, which is pretty amazing.  Had it gone ahead when it was supposed to at the end of July, it would have rained.  We know this because it did.

I took a heapload more photos with my new-to-me (but old-to-my-wife-because-she-gave-it-to-me) Olympus TG-3, but none of the actual Top Force.  I had a pretty good day's racing overall, although I lost an outdrive from the rear ball diff midway through the day and had to swap to a putty-filled gear diff for the final.  In the end I could only manage 7th out of 9, which was a pretty poor show even for me, but the competition was tough and the racing was excellent fun and at the end of the day that's all that matters.  I stayed on late to watch the race of champions and the trophy ceremony (and have another burger from the burger stand, which is the main reason why I go to the Revival in the first place*) and drove home happy that, despite everything the first part of 2020 had thrown at us, I'd still got to race the Top Force on a proper track.

Which brings us full circle.  Revival 2021 has been given the green light (albeit tentative, because if just one person goes off to Brazil without a permission slip, Headmaster Johnson will put the entire country back into detention again) and despite having 3 times more entries than it has spaces, I have been successful in my application.  I had intended to give the Evo a rest this year and run a period-modded Hotshot instead, but given entry numbers we have to accept the place we're given.  So I no longer have to build a Hotshot, but I do have to fix the Top Force.

Basically, it's all feeling a bit tired.  So the remainder of this thread (which will be however long it takes, or until the Revival, whichever comes sooner) will be about the partial overhaul of the Top Force Evo as I get it ready to race once again at the country's premier vintage off road meet.

On Sunday morning, the sun was shining.  This actually happens sometimes.  So I rolled up the garage door and cleared off the workbench.

The rear shock tower is the focus of today's attention.  The mounting point has always looked a bit flimsy, IMO, and although I haven't broken it yet, I fear it's only a matter of time.  Here was a little fix I added last year to try to spread the load in a roll.

These giant red washers were here when I got the car.  I'm pretty sure they're not standard.

Now the interesting thing here is the suspension tower actually moves on those screws.  I can only guess the carbon is worn and oversized, so the tower can slide around unless those screws are done up really tight.  But it's Tamiya plastic, so you can't do them up real tight.

The carbon does look a bit chewed.

But no matter.  This is the brass insert from a servo fitting kit.  It was a tight fit (needed to be pressed into place with a bench vice).

This is the brass insert after I attacked it with a file.

Both sides fitted with inserts and bolted back into place

Also found a larger piece of alu to brace the rear tower.

And that's as far as I've got.  I still need to pull apart the rear transmission to check it over and see about getting replacement outdrives for the ball diff.  I should also open up the front end to check what's going on in there.  The carbon prop is in good shape but the drive cups are seriously worn - probably not worn enough to break on my but would be nice to find some replacements.  I'm not sure if it's a standard part for the Evo - if so I might be able to get spares from the re-re.

Further pics to follow as I dig into other areas of the car and work out what I can be bothered to put right

 

*the food I bring with me to "save money" gets donated to needy racers who don't have their own fridges

[DeadMeat666 1675]

Thanks for posting! In addition to the interesting content, your writing style and humor make this a very worthwhile and entertaining read  

[Mad Ax 9312]

Thanks @DeadMeat666, I'm here to entertain

[Sir Crashalot 235]

Excellent read, cheers.

I often watch the iconic revival videos, and like seeing all the vintage buggys. The conditions in the UK make me appreciate the mostly indoor racing that I do. 

Good luck for 2021.

 

[Robert5000 928]

Brilliant stuff, this is exactly the content I was hoping for!  

[Mad Ax 9312]

@Robert5000 every year at the Revival, I start mentally writing my post-race writeup.  But I never actually post it.  I guess I leave it too long, I forget the trivial details that make an event write-up so much more important, I forget (or don't have time, or am too busy chatting / repairing / drooling* over kits in the pit shop) to take pictures, and I generally perform so badly that I don't feel justified in doing a full race report.

Actually at my last race of 2020, which was a vintage tarmac class at a club event, I sat down after every heat and did a quick write-up of my progress, with the intention of doing a proper race report for the entire winter season.  It was supposed to be the start of a whole new way of racing for me.  Alas, the season was cut short by the sudden resurgence of the pandemic and I didn't get the chance to follow up on what had been a good start.

Hopefully 2021 will be different

*wearing my plague mask at RC events makes my drool less obvious to others but more uncomfortable for me

[ewant81 33]

I will enjoy following your progress here! My TA01 chassis rally car is a very distant cousin to the Top Force Evo, and I do remember drooling over all the hop-up goodies it came with as standard. 

[Mad Ax 9312]

My next plan for the Top Force was to pull apart the gearboxes and check that all is well.  I know I've been through a few different internals in this one but it looks like at some point I had a spur failure (probably back in 2018) and was forced to go back to the old Top Force setup instead of the Manta Ray gears that I had originally fitted for racing.

I started by pulling off the rear diff cover to see what was going on in there.  Originally this car had a ball diff in the back, but at last year's Revival I lost an outdrive and had to swap in a gear diff with some putty in it.  I'll probably keep that in there because it feels about right.  However, the transmission is absolutely full of mush, which most definitely shouldn't be in there.

Yep - that's the Top Force cheese gears under the gear cover.  If you look closely in hi res mode you can see the gears are not evenly worn - this transmission hasn't got long left.

That's a lot of grey goo - aluminium particles mixed in with regular gear grease.

Cleaned

[Mad Ax 9312]

So - the solution to this is to fit new gears.  Two new gear sets are on order - one for the Top Force and one for the Manta Ray, which is currently half a bare chassis with minimal internals.

I thought I'd pull the front transmission apart also to see what the deal is there.

That's looking pretty gloopy.

I think there's some interesting provenance going on here.  Originally this front end would spin super-free if I turned the wheels, but now it backs off quickly, like there's more resistance than there was.  I know I had a diff issue at Revival 2020 (see above) and I did some swapping around of parts.  I think I've ended up with some of the silvered grease from the back end in the front end, so it all needs to come apart.

This part is non-standard and looks like another cheese component, but actually it's plastic - just covered with grey goo.  It's a torque splitter (or centre one-way).  It allows drive to the front wheels but prevents braking.

It's also quite badly worn, probably as a result of getting sand in it, but it's still useable.

So - the front end has been fully cleaned and gone back together with fresh grease, the rear is pending arrival of the new gear set.

Hopefully there isn't much more to do on this chassis now, just reassembly and adjustment.  I had trouble with some ball ends popping off last year, so maybe I should replace those.  The turnbuckles are oddly matched, it would be nice to get a matching set, but it depends on price as I need a full new set for the Manta Ray, and two sets might be pushing it on top of all the other stuff I need to get to make the Manta in a runner again.

Watch this space

[ThunderDragonCy 7877]

You need 50519 gearaet to get rid of those horrid aluminium gears

[Mad Ax 9312]

@ThunderDragonCy I've got two standard NIB gearsets on the way to me.  IIRC there's a speed tuned gear set also but IME I don't need any more speed on BMR's track.

50519 appears to be a CVA shock set?  (I need long CVAs for the Manta Ray - going to be an expensive week!)

[ThunderDragonCy 7877]

9 minutes ago, Mad Ax said:

@ThunderDragonCy I've got two standard NIB gearsets on the way to me.  IIRC there's a speed tuned gear set also but IME I don't need any more speed on BMR's track.

50519 appears to be a CVA shock set?  (I need long CVAs for the Manta Ray - going to be an expensive week!)

Sorry, 50529. It's the so-called Touring Car Plastic Gearset. Same ratios, but no metal. It's off the TA-02. 

[Mad Ax 9312]

1 hour ago, ThunderDragonCy said:

Sorry, 50529. It's the so-called Touring Car Plastic Gearset. Same ratios, but no metal. It's off the TA-02. 

Yep, that's the one - got two of those on order, hopefully here this week so I can get it back together again on Sunday

[Mad Ax 9312]

So I've been having all sorts of fun and games with the old Top Force.  It's been in pieces for a while because I was due to replace all the turnbuckles and rod ends as well as the rear gears, but a couple of days before the Tamiya Junkies meet I realised it basically just needed throwing back together with the blue-tac'd gear diff and fresh gears and it would be fine to run on the astro.

Except it wasn't.  The gear diff went in OK, the plastic spur and idler went in OK, but once the case was torqued down it all seized up.  It would run, but something clearly wasn't right.  I didn't have time to fix it then, so it got left.

On Sunday morning I pulled it out of the box to try to work out what was wrong.  My only thought was the gear case itself was worn or damaged, and the spur was sitting too low and rubbing the bottom of the case.

Here it's held down by what I guess is a standard Evo-style self-tapper

On this side I use threaded screws.  I put nuts on the end to keep the gear case from separating under load, here it was just assembled for testing.

Here's the all-new spur.  Got a bit of dirt on it from the bottom of the upper gear case as I took it off but otherwise fine.

Seems to be clearance here at the front of the gear housing

But that looks suspiciously like a witness mark to me

 

[Mad Ax 9312]

I gave the case a good clean and got rid of some of that gunky grease that was still in there from the last gears that were pulled out (I guess I was lazy and didn't clean it very well), then put it it back together.  Everything looked OK, but it still wasn't turning smoothly.  Something was definitely touching somewhere.

I pulled out all the gears, then put them back in, one by one.  Spur and prop crown were fine, everything turned easy with no resistance.  Then the idler (the diff was already fitted) and again, no problem.  So perhaps that wasn't a witness mark in the spur housing after all - something else, perhaps?

Ah - facepalm - could the pinion be fitted wrong..?  Sure enough, put the motor back in and it starts grinding.  The pinion was slightly too far along the motor shaft and was touching the gear housing when torqued into place.  Gah!  Oh well - at least it was a cheap fix.

I do prefer when Tamiya give an actual motor-body-to-pinion-outer-face dimension in the manual instead of those stupid place spacer things.  Firstly because there must be a dozen different types of plastic spacer and I always forget which one belongs with which car, and secondly because aftermarket motors (especially brushless ones with a completely different nose bearing), aftermarket motor plates and aftermarket pinions make a complete nonsense of the concept.  Well, never mind again, pinion refitted and all is well.

I also took the time to put the turnbuckles on (although I had to re-use some old rod ends on the steering) but it will wait until another day for a proper setup.

[Mad Ax 9312]

After that I turned my attention to one last bugbear on the Evo - the carbon prop rubs on the aftermarket chassis.  It always has done, since before I owned it, and I've never worked out why.  Is the chassis twisted?  Is something upside down?  Is something mis-aligned at the front?  Who knows.  Anyway, it's been like it for years but I finally decided I should fit it before the prop rubs right through and explodes and showers a track marshal with carbon splinters and then he falls over on track in agony and someone swerves to avoid him and hits a ramp and goes into a spotlamp and it falls over on the podium and electrocutes everybody and then shorts out and sets fire to all the tents which then set light to the fields all the way to Bingham and before I've even taken my finger off the throttle the entire Midlands is on fire but I can't see because I've got my plague mask on and my glasses have steamed up, and then people will be in mourning for weeks because some former RC world champions were set alight in the blaze and there'll be Facebook posts of crying smileys with "oh no, it's 2016 all over again" and "someone please wrap David Attenborough in cotton wool!"*

To fix this problem and also to save the Midlands from a fiery fate and keep some famous RC celebrities with us for many decades to come, I used the Device For Making Big Things Slightly Less Big, also known as a File

There.  Next update will come when I've returned the big bore shocks to their rightful place on the Top Force and taken it for a drive somewhere.

 

*I have just eaten half a sharing bag of Minstrels

[matisse 1581]

My favourite device, just beating out the thing-for-making-round-holes 

[Mad Ax 9312]

My last-minute trip to Tamiya Junkies this weekend gave me the opportunity to put the Top Force on track in full racing trim.  Running with modern tyres on dry astro is as close as I'll get to the Revival layout at BMR in a month (the main difference being, at Revival, the astro will be wet).

Immediately the car felt strong, and had lots of turn-in, but over the bumpy areas the back was very flighty.  I could hear the underside slapping the track surface and at least half the time the rear wheels were in the air.  This isn't a handling characteristic that I'm accustomed to taming but I felt I should be able to do something, and it seemed that perhaps the rear was too soft, and standing up the rear shocks a little would help.  Maybe the rear was also too low for the track surface, so a bit more ride height could be in order.

I popped back to the pits and moved the lower mount for the rear shocks inwards.

was:

is:

Back on track the difference was noticeable.  I say noticeable, sometimes I make a setup change that I later learn should have completely ruined the car but it still feels better - either because confirmation bias tells me it should be better or because the short break from the rostrum gives my brain a chance to reset and take in what I've learned about the track.  But the terrible jumpy-roundy at the back had gone away a bit and the car was much more planted over rough stuff.

I figured if that worked then maybe going in one more position would work better, and while this did help more over the bouncy bits, it also seemed to make the car more prone to grip-roll.  Also over jumps it had a tendency to roll sideways and land side-on to the track.  Going back to the middle position improved this a bit.

And that is actually the only setup change I made all day.  The rest of the day was learning the car and the track.  There's still a lot of bouncing from the back of the car and I wonder if some heavier diff oil is needed to stop it moving around so much.  I'm planning on getting to Revival in time for Friday practice (something I've never achieved before) so I'll have time to test my changes before race day.

Still the biggest setup problem is the driver.  It's very noticeable at Junkies where there's only a handful of us and no official marshals, every time a car goes over somebody must climb down the steps to recover it.  A bad driver is punished with aching legs and minimal track time, and I felt like I'd run a marathon by the end of the day.  That said, although I was still making silly mistakes in silly places, I was really getting to know the track's lines and was even getting the confidence to keep the throttle in in places where a good line is essential to get through without hitting a barrier.  That makes all the difference - IME slowing down to zig-zag through something that could be done straight unbalances car (and driver) and makes a mistake more likely, but gaining the confidence to keep the power on and nail it through a that gap takes time, patience and a few good crash-free laps.

In other news - the battery straps seem to have shrunk.  The old HPI chassis requires straps to hold the battery in and it has no lugs to stop it sliding around.  Virtually every run was interrupted by a battery coming out.  I really need to fix that before Revival.  First off I'll use longer straps but also I'll see about fitting some stops to keep the battery from moving around too much.  I also need a new body post, which hopefully comes on a parts tree that has other useful parts on.

[djmcnz 754]

15 hours ago, Mad Ax said:

...There's still a lot of bouncing from the back of the car and I wonder if some heavier diff oil is needed to stop it moving around so much....

The two problems you have need to be treated differently, bottoming out and too much bounce.

I was going to ask what viscosity shock oil you're running? You may need to go up a weight or two. If you do this you may want to wind the spring retainers down a wind (360*) or even two for more preload.

Try adding preload first because it's easy and see if that alone helps with the bottoming out, if it does and it doesn't make a difference to the bounce you're getting then change up your shock fluid.

Those springs look quite beefy and have a lot of winds, do you know their specs?

Just throwing out some ideas, feel free to ignore me! 😎