R500 HPE

[danwebster]

This is it. The moment i've all been waiting for....i'm doing my dream build. 

Just over 5 years ago I did this:

Then a year later I decided it was time for a mid life crisis, I was 34 after all, so I quit my job and tried to earn a living playing with cars. The amount of gratitude I feel to all of my customers deserves another thread all of its own so I won't go into it in too much detail, but despite the last 4 years being phenomenally stressful and difficult, they have to be the most enjoyable years of my life so far. 

Just over three years ago, after building a couple of customer cars that were loads better than my own I decided a quick winter refresh was in order so I tore my perfectly working elise apart and parked it in a barn.

Three years later having done two thirds of bugger all to it things got so bad I considered selling what was left of it, however after some rest over the christmas break, several long conversations with various people and a slight change of circumstances I'm doing the build i've been dreaming of for the last 4 years. 

If you saw my previous build thread you'd have seen that I picked up the registration K20 HPE for the car. That registration is now on my daily runabout because I got another for the elise, R500 HPE, which ties in perfectly with my plan for the car, which is to build a 500 hp per tonne Honda Powered Elise.

In order to hit 500hp per tonne I'm targetting 650 kilos and 330hp. The engine will be a normally aspirated honda of course...but a little different to the norm. I'm building a 2.2 similar to some of the customer builds i've done, except mine will be standard stroke and very big bore, so in effect a short stroke 2.2l engine. Its going to have a few tricks that don't make their way into customer builds for various reasons, 2 ring race pistons for example. 

In thruth, I haven't done nothing to it over the last 3 years, but its a tiny amount of work in the scheme of what i've got ahead of me. 

As it stands the car looks like this:

Its almost completely stripped, even down to the wiring loom. I had the cage made a while back by a top motorsport fab place and its very light. I managed to get hold of a lightly used Tillet B7 seat which is lighter than the runners its on and the rest of the car is sitting on fresh bushes and bearings throughout, but thats about it. 

I started collecting a few parts for the engine and i've been porting my own cylinder head  I have almost no idea what i'm doing so the results will be interesting...

Being a much bigger bore than standard has several advantages. I can run substantially bigger valves than standard but still not suffer from shrouding of the valve. As i'm going for gold with the engine i'm running 2mm bigger inlets and an extra large set of throttle bodies with 54mm chokes so the ports are getting opened out to match the huge throttle body manifold. You can see here how much material needs to be removed from the already gargantuan K20 port to match the manifold. 

Here's one nearing completion:

It doesn't stop there though. I'll be fitting a very trick clockwise motion flywheel that'll allow me to fit a 5.5" twin plate clutch to it. Whilst light flywheels have a noticable effect on the response and inertia of an engine, its the clutch that makes the biggest difference. Reducing the diameter from over 8 inches for the standard honda clutch to 5.5 is mind boggling, its the setup that most single seaters run so it'll sound suitably bonkers....and be undrivable, but who cares. 

The crank, rods and pistons are pretty special too. I'll go into some more detail on those when i've got some pictures, but the end result is an engine that feels like it has no flywheel. Think mclaren F1 or Porsche carerra GT and you're somewhere near, but not quite as responsive

So here goes, to say i'm excited is an understatement. I'll be doing all the evenings and weekends I can spare on it, which by my previous experience means many late nights listening to radio 2, but at least I don't have to do it on the drive in the snow any more!

Stay tuned.

[Daveb99]

Nice one Dan, sounds like it will be an absolute beast.  It’s great that you finally got time to have a crack at this..

As one of your customers in the last couple of years I wish you all the very best, your work is always stunning so I expect this will be no exception.

I may be bringing the V6 to you this year for a service.....if you can squeeze me in!

[danwebster]

Thanks Dave, i'm sure I can squeeze you in!

[jonnyfox]

Looking good buddy.

 

[stockhome]

Looking forward to the build thread Dan

 

[danwebster]

Time for some crank porn.

This is a standard K20 type R crank shaft:

They're forged steel and virtually unbreakable but pretty heavy. 

This is a Clockwise motion billet steel stroker crank (bottom) and the crank i'm using in my engine (top). Notice they're both single counterweight and as a result much lighter.

You'll probably also notice that mine looks like an oem crank rather than aftermarket. That's because it is...its out of another K20 but not a type R. Its also got smaller big end journals which in turn means smaller rods and even less reciprocating weight. The rods are pretty trick too, also clockwise motion items. As I mentioned they have a smaller than usual big end which makes them lighter even than the usual rods I put in the 2.2 stroker builds. They're also longer, which is facilitated by the 2 ring pistons, which have a shorter distance between the gudgeon pin and the crown. Longer rods are great because they mean the pistons 'hangs' at the top of the bore longer and whips around the bottom faster, which in turn means more bang for your buck. Its a very small incremental improvement, but with the big bore and bigger valves it all adds up.

[Martin R]

Good work. First daft question. Does the large bore and short stroke not give rod angle problems?

[danwebster]

It’s a good question Martin but actually it has the opposite effect.  I’ve called it short stroke but it’s aftually standard stroke and yet due to the shorter piston crown height the rods are even longer than standard (whereas with a long stroke 2.2, the more conventional route, you run a shorter rod than standard) so the rod / stroke ratio is even better. 

[@ndy]

Sounds stunning Dan, Look forward to following this thread and nice to hear you are keeping it NA

[danwebster]

NA ALL THE WAY!

[danwebster]

A minor update today, I went to the autosport show and got a healthy discount on a rather special new gearbox and a nice new steering wheel!

[@ndy]

Come on Dan, spill the beans on the gearbox......

[danwebster]

6 speed, dog engagement, straight cut, H pattern

 

[Martin R]

It obviously came with a few sets of ear plugs 

[@ndy]

Nice close ratio's based on the rev drop details and with straight cut cogs to, this is going to be one epic car.....