Track-focused Atom 3

Owner

Garmster

Location

Surrey, UK

Project

Track-focused Atom 3

Why?

I want an Atom build that is built for the track with slicks and sustainable performance. I’m not going to be able to get more performance out of the Atom 3 engine, reliably, unless I start from the foundation up and that means I need an excuse to rebuild the engine.

For me the ultimate track day car is not a simple equation of building the fastest car ever, that maybe the case for someone who is racing and competing in their Atom. Let’s not lose focus, this is a track car not a race car. So reliability has to trump out right speed. I’d rather go a couple of seconds slower per lap than having my car let go. I’ve been there, seen it and have the badges. All that said, I did not say performance is not important but it simply comes second to reliability. So that was the key for me, to build a track day car that was firstly reliable and then to squeeze as much power out the Atom as possible without compromising reliability.

Shopping list

Engine – needs to be powerful, enduring and reliable.
Suspension – needs to make me feel like a driving god, which I am not.
Tyres – the addition of slicks is a must but introduces other challenges.
Aero – that actually works and provides downforce.
Tech – need some video, data and assistance with driving.

Starting point

The below pic gives me the perfect excuse to rebuild the engine. My engine gave up at Spa and I believe this was due to oil starvation, once again probably relating to the fact that I’m now running slicks. A key consideration for the engine build will be the oil pump, baffling etc. Slick tyres will increase stresses on the car and one of the must have mods will be the uprights. The factory uprights, bearings and shafts will come under much more stress. As you can see from the picture below, my factory hub literally snapped in two.

Question: Was the old sump baffled?

Answer: Yes the sump was baffled as best as it can possibly be baffled (from factory) but the problem is or was more likely to do with the fact that the FN2 K20Z4 (Atom3) engines uses a balance shaft oil pump, which is not good for high revving and extremely restricted for baffling; plus the fact I was on slicks. I’m surprised there’s any room for an engine let alone a baffle, it’s massive. My new engine will have a balance shaft delete kit and 4PISTON race ported oil pump. As well as saving weight, this will be better for high revving engines with less aeration. I’m also going to add oil pressure and temp gauge to my car, another very important mod. As it stands, its binary. My current 3.5 dash will only show the oil pressure as one or zero, and if it’s zero, it’s too late.

Uprights

I have replaced the factory uprights with Palatov billet uprights with Porsche bearings. The uprights are stronger and should more than suffice for handling slicks and, if desired, 17 inch rims and wider tyres.

Suspension

I wanted stiffer suspension now that I have aero doing its job.

As far as suspension is concerned, there were three choices with three varying price tags, I’ll start with the lowest cost option first:

  • Assuming you have the Bilstein 10-way adjustable suspension, do nothing.
  • Stiffer springs – move the rear 60N/mm springs to the front to replace the 50N/mm springs and order a new set of rear 70N/mm springs from the factory.
  • Ohlins TTX 36.

A set of Ohlins TTX 36 are on their way and will be going on very soon.

Engine components are ready

All engine components ready to be built into my new MMR Atom 2.2 engine.

Engine build is done

The 2.2 engine build is now complete thanks to Michael Morrison at MMR race engines. Engine should be installed this week followed by the engine remap the week after.

Although this engine would be good for 800bhp, I’m not doing anything with the JRSC at this stage other than a water/meth kit. So in terms of power, I simply want to deliver up to 350 horses reliably. That’s my goal for now.

Injectors

While I was at it, some Dynamics 1050x injectors were added for better fuel flow and consistency.

Cooling intake temperatures

Once the new engine is in, its supposedly will be good for 800bhp. Calm down gents, I won’t be going anywhere near that. The Atom as we all know is held back by the Jackson Racing supercharger (JRS) and specifically the air intake temps. The obvious answer to this is the £9k Ariel 3.5R upgrade (i.e. side pods, charge cooler and oil cooler) to help lower the intake temps. I’m already spending £20k on engine, aero and uprights, so need to tighten the belt a little. Maybe a water/methanol injection kit is the way to go to help bring down intake temps on the JRS?

For a boosted Atom that sees the track I’d say you want an oil cooler and a charge cooler or water radiator, you can’t have both. I’d say use the air intake snorkel for an intercooler, second water radiator behind the main one horizontal (hot country radiator), and the Cup car oil cooler. It should still be a bit cheaper than side pods, but not by much.

Water/meth – initial thoughts

I’ve gone for the AEM v2 water meth Injection kit, which should be with me early next week. I’m hoping to install the tank behind the seat but I think judging by the pics that another owner posted, there may not be enough room. I’ll be discussing the options of mapping, i.e. advancing the timing when the intakes temps are x (eg: x = 40c) which means the meth must be injecting. Otherwise a more moderate timing will be applied i.e. no meth is being injected. This should act as a failsafe but needs to be discussed in more detail.

Engine install started

Just waiting for the oil catch tank to arrive and install the AEM water meth kit. I also have a solution for the oil pressure and oil temps to be displayed on the OEM dash.

Oil temp and oil pressure

In order to get the dash to show oil temps and oil pressure, I added a sensor cable that will plumb in to oil filter cooler sandwich plate and then needs to be wired back to the dash. It was very tight and only just fits, but we got it in.

Oil catch tank

Oil catch tank now installed. Not much room left — but just enough to squeeze it in. Next the water/meth kit and then run-in the engine followed by mapping.

Question: Interesting you are going to run a meth kit. Where will you store the tank given there is not much space? Also interested in understanding the rationale of fitting such system to an Atom, could you not get the desired ~360bhp just by regular stage maps, turbo mods etc?

Answer: Great question and gets to the crux of my rationale. Firstly, I could have just left it alone and pottered around with 300bhp but unfortunately I have to tinker. I’m not an expert but then I’m not sure you need to be when you break it down in simple terms. Remember I started with an engine where I fried the pistons, rods and crank so I had to replace/rebuild my engine and have better oil management. I could have gone out and bought a stock K20 and paid £10K for the 350R from Ariel or £10k with TDI north on a turbo and achieve 350bhp. However, you’ve built your house on dodgy foundations. I track my Atom ALL the time so my expectation is that I will be driving through the rev range and every gear. How long would it be before I throw a rod or fry a piston, probably not long. And when you have a chat with TDI or Ariel, they’ll tell you, your engine has to be up to the job for any of these big upgrades.

No matter what I do, I had to build a solid foundation if I want more power so I decided to go the full hog. Forged, lightened, billet, strokered, polished and ported, cams, baffled sump, oil cooled, dash upgrades etc etc. Now I have an engine that is good for 800bhp if only we can get more air into the chambers. We will see some increase in power with the 2.2 stroker kit, ported and polished head, cams and lightened billet crank etc but unless we can get more air into the chambers, we can’t get more power. It takes two to tango and in this case its air and fuel. The Jackson Racing supercharger (JRS) is at its limits and can’t drive any more air without driving intake temps up. Trying to drive the charger harder by changing e.g. pulley sizes will increase the intake temps to the point where you’ll probably get pre-detonation causing engine damage. In any case you’ll be losing horsepower exponentially as the air intake temps get higher. This is why Ariel’s 350R upgrade will combine a smaller pulley to drive the charger harder as well as charge cooler to reduce the intake temps amongst many other bits and bobs.

So why the meth kit? Simple. To get more power I could:
— Add a turbo = £10k
— Add 350R kit = £10k
— Add meth kit = £500

Given I’ve spent so much money on the engine and other bits I need to take step back and pause to take stock of where I am, given I just bought another car.

No doubt I will be installing a turbo at some point but for now I want reliability with a little extra horses. Oil cooled and baffled, now I need to focus on more air. So the water/meth kit is a simple way of getting the intake temps down and allow better fuel and dense air combustion. Untuned you could achieve 15 to 30 bhp and tuned you could be looking at 40 — 80 bhp. Maybe I’m being over optimistic, but we’ll soon see when I take the Atom to be mapped. I’ll make sure that there are failsafes in place so that if the ECU detects an increase in temps i.e. the meth has stopped working then it will adjust the timing etc accordingly.

There may be mistakes in my assumptions and I am happy to be corrected. I’m always happy for people’s input so please don’t shoot me down if you think my rationale is a little skewed.

Oil pressure failsafe

The pic below shows the sensor from Race Technology that will provide my Dash2 with oil pressure and no longer to rely on a ‘1 or 0’. I want to see ahead of time — and at a granular level — what’s going on BEFORE my engine goes bang.

Water/meth – install

As mentioned, I went with the simple AEM v2.1 meth kit. We had to make an inlet for the meth injector as we can only put it in the rubber hose before the throttle body and after the mass air flow sensor. This only leaves us with the rubber hose in between the two. I could have inserted the nozzle directly into the rubber pipe, but it probably would have failed at some point. So we cut the pipe and inserted metal tubing between the cut sections to insert the injector nozzle.

Housed the water/meth tank behind the Atom seat bulkhead, fits nicely and will be easily accessible. Used some bolts to tilt/space it away from the engine firewall so that it’s a better angle to access and pour in the water meth fluid.

Almost done

The Atom has completed its 100 miles running in, all that’s left is an engine oil change and reconfigure of the Dash2 before I go for a remap. Thought I’d do a quick video to show the meth kit, oil cooler and catch tank.

Dyno run #1

Took the Atom for a rolling road map session and all did not go to plan. Apart from the wrong FlashPro and the driveshaft popping out the gearbox (easy fix), we had two issue which need to be fixed with the IAT’s and the meth kit.

First the meth kit, DO NOT inject pre-charger, there is no point and you will lose power, not gain. I know some of you are saying “I told you so”. We live and learn. The plan is to tap the meth injector to the inlet manifold. This also gets round the potential for any water that’s not vaporised getting in to the charger as water cannot be compressed. On the AEM meth kit you have three nozzles, I’ll use the medium based on my experience.

Secondly, the MAF IAT sensor is useless, it’s giving you the ambient air temp as opposed to the charge temps which is what you need. The MAF sensor is located by the air filter and shows IAT’s around 15 degrees. So going to take the signal and ground wire from the MAF sensor and re-route it to a new IAT sensor where I will need to tap a hole into the inlet manifold (courtesy of a pic from Ian G’s build):

Lessons learned

IAT sensor added now into the inlet manifold

  • SG1 = green/black (GROUND)
  • VCC1 = red/yellow (5 VOLT from ECU), range 0.1 to 4.0 volt, circa 1.8 volt @ normal running temp
  • MAP wire remains redundant = green/red

This will allow the tuned map to take proper intake temps into account, as opposed to the ambient temperatures.

Meth injector has also been relocated to the inlet manifold. As I previously mentioned, injecting meth pre-charger will end up losing power and that is fact and tested on the dyno. Meth has to be injected post charger, directly into the inlet manifold.

Dyno run #2

Another bad day on the dyno, once again the driveshaft popped out the diff/gearbox, so I knew I had a fundamental issue. Got it back to investigate and found the inner CV joint is shot. I could see some metal fragments in the joint, which you can kind of see in the grease as shiny metal. Also see the actual housing has been severely scored on the inside. 

However, managed to get a pull on the dyno before my Atom decided to throw gearbox oil over the rollers, so I do have a safe map at least. Pulled 326bhp but could not do any real tuning.

Spoiler alert: lots of useful tech info about driveshafts and inner CV joints can be found on the forum here. For reference though, the Atom does NOT use a Civic Type R inner CV joint.

Dyno run #3

Not having much luck with the meth, I have decided to abandon the idea of using meth. We were consistently pulling just shy of 320 BHP without issues. As soon as we introduced the meth, we had to massively compensate with fuel, to the point it was simply not going to be reliable. For now the meth will have to stay on hold and should I want more power, I will either turbo the Atom or go with Ariel 3.5r upgrade. As mentioned previously, the foundation is all there.

Slicks

As far as slick tyres are concerned, I have tried two size combinations:

  • 15″ front and 16″ rear (standard set-up)
  • 15″ front and 17″ rear

I have also tried three different tyre brands: Pirelli, Dunlop and Avon slick tyres. I have found the following combo to give the best performance as far as slicks go, using the standard wheels from factory:

  • Avon slicks (A53 which is a soft compound) 190/570R15
  • Avon slicks (A545 which is a medium compound) 240/600R16

Don’t be scared to use the soft and medium compounds together! They sit on separate axles and work perfectly together. I originally used the A53 compounds on the rear of my Atom and they were blistered by midday on my second track day. The A545 on the rears are awesome and I’ve probably been through five track days on them.

Aerodynamics

So…what’s left to achieve for the ultimate Ariel track day car?

  • Uprights and slicks – check
  • Engine swap – check
  • Baffled sump and oil tank – check
  • Water/meth – check
  • Driveshaft and inner CV joints – in progress

Next: aero, courtesy of Reverie Limited

Downshift auto-blip

I know there will be the purist out there that think it’s sacrilege not to use heel and toe but for those of us who are too old and can no longer bend in certain ways, get yourselves the auto-blip device from https://www.auto-blip.com/ it works really well with the Atom. The auto-blip automatically blips (opens) the throttle when downshifting gears. This allows the driver to focus 100% on braking while simultaneously downshifting through the gears.

Shakedown run

Had a shakedown test at Brands Hatch Indy circuit. It smashed everything in its path albeit not much competition out there. I would have got a sub 50 second lap in had it not been for traffic which is a significant improvement on previous lap times. So the verdict is the aero and car are working well. 

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