Tuesday, 22 September 2015

R500 (not) Wide Open Throttle and first power run with video

A bit of background info:-
Some of those avid blog readers will recall that I've attended only a handful of track days this year, starting off with Folembray in France...

Whilst at Folembray I noticed that going up the hill in fourth and fifth gear the car felt, dare i say it a little 'under powered'.  I took note of it, and put it down to the ZZR tyres, but thinking back to it I've always thought the car hasn't really pulled that well in fifth and sixth gears...

The car was then flat floored by Rob at Ratrace motorsport, and I went to Cadwell Park for another track day... And once again, I noticed the same feelings... Again putting it down to the additional weight of the ZZR tyres I made nothing of it and just thought that was the way it should be.

Nevertheless, a week or so ago at Snetterton, I had to fit the RaceCo exhaust and going down the back straight there the car felt like it was considerably hesitating.  A few calls to Rob at Ratrace, he suggested it could be the throttle bodies out of balance or a top end misfire, I discounted the throttle bodies being out of balance, as the car had just been returned from a service by CC midlands, and this is part of the service.  I decided not to run the car anymore on circuit and headed gingerly home.

A few more calls to Rob at Ratrace motorsport, after which he suggested I contacted Steve at Track n Road performance, to get a power run done and take things from there.

Onto the session with Track n Road:-
So... yesterday the weather couldn't have been better for an hour and a half blat to Rainham - torrential rain!  Not one to cancel an arrangement, I donned my wet weather gear and headed off.

The car wasn't running great on the way there, and even though the rain was pretty much the worst we've had this year, I was happy to be on my way to get some answers.

I arrived after a slow two hour drive and a proper soaking, and it was straight down to business for Steve and Jim. The aim was to run the car with the cat bypass pipe and standard R500 can, then with the Raceco can, then with the Raceco can and carbon airbox to see how this effected the fuelling...

The car was put on the rollers, strapped down and plugged into their dyno... Immediately they noticed a few things:-
  • The map is a Cosworth map, even though it's not a Cosworth engine
  • The Cosworth map is locked, so they can't remap this version
  • The car was running poorly
  • They couldn't get full throttle
  • They think the Lambda sensor is burnt out
They ran the car with a small amount of revs, and started to disconnect the spark plugs one at a time to see if there was any difference, and quite worryingly, there wasn't much difference when they disconnected plugs three and four... Whereas when they disconnected plugs one and two you could immediately hear the difference.
Steve fiddling with the throttle
Steve fiddling with the throttle
The air filter was removed, and straight away Steve said that the balance of the throttle bodies was 'miles' out!  Not only that the throttle on the rear barrels wasn't opening to more than 75%, and as roller barrels only offer a benefit when opened over 80%, I was seriously down on power as a result of this - Steve suggested around a 40bhp loss!

With the throttle bodies being awkward to adjust in situ, they removed the inlet trumpets, and the carbon backplate - which was hard to remove as it had what seemed like the factory glue holding it in place along with the bolts.
Jim removing the inlet trumpet backplate
Jim removing the inlet trumpet backplate
With the inlet trumpets and backplate removed here's a look at the roller barrels in the closed position.  I'm kicking myself as I didn't get a shot of the previous 'Not Wide Open Throttle' position, and must admit I had to laugh as my number plate is R500 WOT (Wide Open Throttle) which Steve and Jim are pretty confident the car has never had since day one!
Caterham R500 Duratec roller barrels with inlet trumpet and backplate removed
Caterham R500 Duratec roller barrels with inlet trumpet and backplate removed
The throttle cable was adjusted, the throttle position sensor was also adjusted and then the 'wide open throttle' position was setup to finally be 'wide open'.
Caterham R500 Duratec engine with roller barrels finally in the 'Wide Open Throttle' position
Caterham R500 Duratec engine with roller barrels finally in the 'Wide Open Throttle' position
About three hours after I arrived, the backplate, inlet trumpets and air filter were all put back and the car was restarted with the Lambda sensor disconnected.  The car immediately sounded like a normal engine, with none of the misfiring and lumpiness I've been experiencing all but gone!

So, here's the highly anticipated power run video:-

And the results of the power run, along with the graph:-
  • 255.1 bhp at 8,600 rpm
  • 171.1 lb-ft at 6,174 rpm
  • 148mph top speed
  • 464 bhp/tonne (based on weight of 550kg)
Caterham R500 Duratec power curve graph
Caterham R500 Duratec power curve graph
So what's next?
I'm going to order a new Lambda sensor for starters... The guys from Track n Road are going to make some enquiries as to how to get into the map to customise it, but as it's a locked Cosworth map, it'll be more than likely that they'll get a new map board, and start with a different map and take things from there.

The plan will be to create three maps for the engine:-
  1. Map one will be for standard R500 can, cat bypass pipe and piper cross air filter
  2. Map two will be using the Raceco exhaust, cat bypass pipe and piper cross air filter
  3. Map three will be using the Raceco exhaust, cat bypass pipe and carbon airbox cover
The aim with the new maps will be to improve power delivery and drivability, and if there is any additional BHP then great.  The maps will only be switchable by laptop, so I'll need to take my laptop as well as all the exhaust and airbox gubbins whenever I go to a track day - proper geeky, but... If it work's and keeps the engine and fuelling in tip top condition I'm happy.


  1. They didn't tweak your flux capacitor.... I find this always helps. Especially on re-entry, where is Biff?

  2. Just a thought, would it be worth doing a dyne run with your cat in place. It is needed for competition and its something very worthwhile doing if you might want to do hillclimbs and sprints at a later date. I would be interested in the results as I currently compete with a k-series caterham and I have always wanted a R500.

    Like your weight figures, can the caterham make 263bhp with a cat in place, caterham suggest it should?

    1. I'm still researching what the best map solution is. There are plenty of options out there, but I doubt I'll be getting it mapped with the cat fitted...

      I'm pretty confident that the motor in it's current form won't make 263bhp as all the 'mappers' I've spoken with have suggested Caterham were optimistic to say the least with the 263bhp figure with most cars only outputting 250bhp, so for mine to have 255.1bhp is very good and testament to a well run in engine.

  3. Thought you might like to see this graph https://c2.staticflickr.com/4/3705/13509019744_3521dde5d1_z.jpg
    Basically an R500 engine and the red trace is remarkably similar to you car (wheel horsepower). The blue was with a custom 4:2:1 BTB exhaust . . .

    1. Hi David,
      Found some of the info you've been posting online useful... Can't see how I can get in touch with you as I'd be keen to chat over a few things... Can you drop me an email using the contact form on my blog please?


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