VIN 12306 'Auryn' : RHD rebuild

[stunned_monkey]

Interesting… it occurred to me too that you’d need new manifolds as the turbos can’t simply be switched. Is Ed planning combining the flow across the back or leaving it separate? IMO leaving them separate does not sound good, being basically two 3-cylinder engines. Having the exhaust exiting rear does reduce the length of exhaust you have to play with but also gets rid of the ugly exhaust U-bends on front of the turbos in favour of light weight air intakes. The centre of gravity of the turbos is also further forward – a minor point. I’m not sure where the fire risk comes from, the DeLorean engine bay is about the most ventilated of any car I know and the bits generating heat are all south of the fibreglass anyway. I suppose the cats on yours can be located right down low in the U-bends and quite a bit of air rather than across the back. How come you’re catting it out of interest? It’ll make initial tuning all the more critical for sure.

[stunned_monkey]

Looking a the photo of the alternator above, it’s mounted higher up than on the Island kit I’m familiar with which required relocation of the coolant bottle to make room. I assume it was to maximise wraparound of the belt on the water pump pulley which is sorely limited already on the twin turbos. Any problems with reducing it still further? Also it makes for even tougher routing of the coolant feed – is yours coming through the belt? That’s what we ended up doing on #2727 though it’s less than ideal.

[Starglider]

stunned_monkey Wrote:Is Ed planning combining the flow across the back or leaving it separate? IMO leaving them separate does not sound good, being basically two 3-cylinder engines.

I suggested a crossover pipe. Ed believes that it sounds better without one (and there is not much difference anyway). I agreed to give it a try but if I don't like it we will be adding a H-pipe (at the same time as doing the exhaust tips).

Quote:I’m not sure where the fire risk comes from, the DeLorean engine bay is about the most ventilated of any car I know and the bits generating heat are all south of the fibreglass anyway.

AFAIK the Legend prototypes (at least one that I have photos of) had two hot cats plus muffler crammed in where the stock muffler goes. This dumped a lot of heat into the heatshield right next to the belts and rear fascia.

Quote:How come you’re catting it out of interest?

Because a production turbo would have been catted. Also it is one less thing for the DVLA to complain about.

[Starglider]

Coil pack is installed. Still working on the air piping and ECU.

[Guinney1971]

WOW !!!!!

[Darren C]

NOT a good place for your coils......

You'll cook them there.

[Starglider]

Darren C Wrote:NOT a good place for your coils......
You'll cook them there.

Really? That's where the fuel distributor was (replaced by the EFI system); I wouldn't expect it to get any warmer than the intake manifold. Ed has used roughly this layout on several previous engines apparently without problems. Still I'll keep an eye on it.

Ditching the original fuel system isn't early-80s-accurate of course but given the difficulty of getting and keeping a good tune on K-Jet twin turbos that's a sacrifice I'm willing to make.

Build has been delayed due to the original crankshaft turning out to be warped; had to be removed and replaced. There were no engines with the original Wooler Hodec parts find so one was sourced separately and almost entirely rebuilt; new bearings, pistons, seals, pumps etc. Rockers turned out to be damaged and now the crankshaft, so pretty much the only parts retained are the cylinder block, crank case and flywheel (machined for lower weight).

[Chris Williams]

So out of interest (not picking fault with anyone or anything) what (if any) was the difference between a stock engine and the legend, excluding the twin turbo's did they do any other work to them? More importantly who refurbed the engine and did not notice the duff crank and duff rockers?
It's a shame it's been delayed would have been the ultimate Xmas pressie for you!
Chris

[Starglider]

Chris Williams Wrote:So out of interest (not picking fault with anyone or anything) what (if any) was the difference between a stock engine and the legend, excluding the twin turbo's did they do any other work to them?

As well as the turbos, exhaust manifold, intake, intercoolers and scoops, the Legend engines have forged pistons, different cams and a seriously modified ECU. I suspect there's also a different distributor with a mechanical boost adjustment, although I haven't been able to confirm. The prototypes had some other convenience and layout modifications e.g. different coolant bottle, but Ed thinks many of these would not be present on the production car, as the company would prefer to retain standard parts where possible.

Quote:More importantly who refurbed the engine and did not notice the duff crank and duff rockers?

Ed noticed the burned rockers when doing the rebuild. He didn't notice the warped crank, but I can't really blame him as Chris N told him the engine was good. Chris N bought the engine partially dismantled from a guy who swore blind it was running smoothly before he pulled it from a wrecked car. Apparently this was a serious misrepresentation.

[Chris Williams]

Quote:As well as the turbos, exhaust manifold, intake, intercoolers and scoops, the Legend engines have forged pistons, different cams and a seriously modified ECU. I suspect there's also a different distributor with a mechanical boost adjustment

Ahh OK I did not realise the internals were changed that much.
Chris

[stunned_monkey]

Starglider Wrote:Really? That's where the fuel distributor was (replaced by the EFI system);

The fuel distributor, with the exception of two O-rings, is an entirely metal assembly. Ignition coils are almost antirely polymer-based (though this doesn't automatically make them more prone to heat).

Starglider Wrote:As well as the turbos, exhaust manifold, intake, intercoolers and scoops, the Legend engines have forged pistons, different cams and a seriously modified ECU.

There is/was no ECU, as K-jetronic is entirely mechanical. The only electronics are the ignition amplifier (which replaces points and is entirely "dumb"), the idle control module which has nothing to do with actually driving the car, and the lambda ECU which fine-tunes the mixture.

The fuelling is dealt with pretty easily with a custom built control pressure regulator which drops the control pressure with boost. The stock 066 cpr already has a similar function with vacuum but it isn't straightforward to reengineer.

The real challenge would be the ignition, but the stock dizzy has a vacuum advance control - however making this bi-directional and therefore boost-retardable is limited because the spark can fall off the end of the rotor arm. The same would be true of any plug-through electronic control module.

IMO it's a bodge to simply prevent the advance higher in the rev range as this is a function of engine speed, not boost and most of the fun can be had lower in the rev range where the PRV is a monster torque-er.

Personally, I'd investigate the use of a wastegate actuator to rotate the distributor under boost, much as you do when setting the timing. Whether it has enough throw to affect enough retard is anyone's guess.

This is all academic because modern EFI eliminates all these question marks.

[Starglider]

Ed has the car running on the dyno at 240 WHP, still fine tuning (that is 280ish BHP, or 320 in Internet forum HP ). Hope to collect it later this week, will post torque & dyno graph. Still no brakes!

stunned_monkey Wrote:and the lambda ECU which fine-tunes the mixture.

That is what I mean, I read that the mixture control electronics were replaced, I don't know what with.

[Chris Williams]

Quote:(that is 280ish BHP, or 320 in Internet forum HP ). Hope to collect it later this week, will post torque & dyno graph. Still no brakes!

That's very impressive what brakes are you going for Martins?

Chris

[Starglider]

Chris Williams Wrote:That's very impressive what brakes are you going for Martins?

Stock for now. The budget has been seriously stetched by all the extra work Ed had to do, also Martin's brakes would complicate registration (can't say the drivetrain is original and they don't have a mechanical handbrake so wouldn't pass IVA). Might upgrade to either Martin's or Ed's sports brake package some time next year. Ed only has a solution for the fronts at the moment but is working on the rears.

I'd be interested to compare dyno charts with a single turbo of similar peak boost. The twin is only maginally more efficient at making peak boost (does so with slightly less restriction thus a little more peak power), but should come on boost faster and make more power & torque lower in the RPM range.

[Chris Hawes]

The handbrake in Martin's kit is mechanical