VIN 12306 'Auryn' : RHD rebuild

[Starglider]

stunned_monkey Wrote:There's a chap in the RAOC who'se doing wonders with the 2.5 engines. Now up to 350hp at the engine and over 300 on the rollers, and that's with re-mapping the standard ECU! (and a chargecooler and a lot of engine internal work, but still looks stock externally)

As you know this is partially a retro/reproduction build rather than a straight power build, but Ed still thinks he can hit 300 bhp with the strengthened gearbox and appropriate EFI setup. The Legend-style intercoolers shouldn't affect the raw power noticably, just a little more turbo lag and significantly more heat soak than chargecoolers.

Quote:BTW just a word on the flasher relay - careful you get one that makes the required ticking noise, and where the pin-out is correct. The DeLorean uses a relay whose pin out does not match the majority of 3-pin relays - and relies on the external capacitor to function.

I'm using the CF13GL-02 as recommended by Ozzie. Seems to work fine; more than enough click with the extra relays in the side marker control unit.

[stunned_monkey]

Very interested to know what head work and cams he's going with. Is he doing his own grinds, or runing a set of Renault turbo cams (like the Venturi 260)? If I've learnt one thing from Martin F, it's that while you can easily get good results, with a bit of know-how and not a lot of extra work, you can get great results - not just outright power but the way the thing drives, fuel economy and so on.

For example, on Rich J's 2.5 when combined with Martin F's fast road cams, you gain an extra 5-10% with stock 2.5 heads by back-cutting the valves. This costs about £70. Or to put it another way, even less boost required to maintain stock power levels. Before we pulled everything apart, Rich was running 1 bar of boost. After reassembly with new cams, new chargecoolers and that valve work, the thing was slipping its clutch on 0.8 bar.

[Starglider]

stunned_monkey Wrote:Very interested to know what head work and cams he's going with.

I'm pretty sure he's using these cams; I don't know where they're from or if it's the same profile used in DMCH stage 2 engines. Valve & port grinding is on the invoice but I don't know specifics e.g. backcut angles.

[stunned_monkey]

But they're NA cams... :?:

[Starglider]

stunned_monkey Wrote:But they're NA cams... :?:

Well, that's what they looked like. When I was last there I only saw them briefly sitting in a cardboard box, so I don't know if the profile is different.

[Starglider]

stunned_monkey Wrote:Very interested to know what head work and cams he's going with.

I spoke to Ed and confirmed that odd-fire is being retained via coil pack, the ECU is capable of per-cylinder tuning and will be using twin wideband lambda sensors (one for each exhaust manifold). Not sure about the cam profile but I'm confident Ed knows what he's doing. He also said that in his experience (presumably of engine-swapped cars) 250 whp is the sensible limit for the DMC-12 before the platform can't handle it properly. Given transmission losses that makes 280 to 300 bhp a sensible goal for engine tuning.

I have come up with a plan for the exhaust tips, I liked the double square ones from the DMC-12 turbo racing sketch;



but also these custom triple ones I saw on a US car;



although it might be restrictive. Also Ed didn't want to block direct view of the red hot cat element that a straight through single would have So I decided to go with triple 2" square on each side, but only single & double square are available. Fortunately I convinced Chris to weld together six single squares with some stainless Y expanders from big rectangular tips to make twin triple square tips. Unlike the custom one above there won't be a visible shroud, just three slightly larger sharp edged squares.

No horns in the WH parts pile so substituted similar-looking decent-sounding modern Bosch units, will splice in a relay as well since I don't like putting that much current on the stalk switch.

[Chris Williams]

Looking forward to seeing the pictures as it all goes together. I'm guessing that it wont be long before the tub is due to be fitted? Once the engine Etc is in?
Chris

[Starglider]

Chris Williams Wrote:Looking forward to seeing the pictures as it all goes together. I'm guessing that it wont be long before the tub is due to be fitted? Once the engine Etc is in?

Tub is already on the frame, doors are on, panels are going on at the moment. Wheels/brakes/tyres are currently scrap units pending finalisation of the plan for those parts; various ideas from Ed, Martin and Welmeod that are still in development.

Martin; I got in touch with Kevin at GTO Racing and he confirmed that he machined off some webbing on your box to make the Quaife LSD fit into the UN1 casing (when flipped over for rear engine use; as supplied it fits perfectly in front engine orientation). So FYI for anyone else considering putting the auto-torque-biasing diff in their DMC-12, it's fairly straightforward but you need someone who knows gearboxes and is ok with grinding the casing. You can see the problem (diff rubbing on casing and not meshing properly with output shaft) in this photo;

[Guinney1971]

have to say, I'm not a fan of that exhaust tip on the black car - I seem to recall Vauxhall fitting
square exhaust pipes on the 24v Senator, Astra GTE and poss Carlton GSi 3000 as it improved
performance at the time compared to the normal round/oval tips - although I'm talking over 20yrs
ago and in the days before Catalysts became a requirement on new cars (1993).

[stunned_monkey]

Interesting choice of words there "before the platform can't handle it properly"

I've preached something similar in the past thansk largely to having driven some very fast turbo PRV cars. I agree there's a sensible limit that's pretty swift before you have to start upgrading brakes, suspension and the transmission. Thing is, you're planning on those anyway Everyone recognises the transmission as being hurdle #1 when going beyond 300ft-lbs. Of course I'd say the brakes and rear ARB need doing too! My opinion is that the front lower control arms need converting to wishbones and one day I might even put my money where my mouth is (I have a design, just not had the inclination to realise it)!

The only other item (and it's a small one), is a torque link added to the engine, otherwise the engine and gearbox mounts will take a pasting.

The CV joints are common to 80's 911 turbos and are very popular to this day and will take well over 500hp. The trailing arm bolts... well okay, they aren't too clever but are cheap and easy to change and give plenty of warning when damaged.

Also a lot of the potential violence can be tamed with studious engine mapping.

[Starglider]

Guinney1971 Wrote:have to say, I'm not a fan of that exhaust tip on the black car

It does look a bit busy. The DMC-12 is an angular design so square makes sense, and the six squares / six cylinders link is nice. However the DMC-12 is also somewhat minimalist, making an over-complex exhaust seem out of place. That's why I considered making something similar to the one above using stainless box section, but settled on three simple squares instead.

Quote:I seem to recall Vauxhall fitting square exhaust pipes on the 24v Senator, Astra GTE and poss Carlton GSi 3000 as it improved performance at the time compared to the normal round/oval tips - although I'm talking over 20yrs
ago and in the days before Catalysts became a requirement on new cars (1993).

AFAIK exhaust performance depends on cross sectional area and how many sharp bends you have, that's it. Round pipe is slightly preferable for the lower surface area: less parasitic drag. Using square pipes for the main exhaust could increase performance if you're space limited in one dimension and it gives you more cross-section than a round pipe, but just the tips shouldn't make a measurable difference (as long as their combined cross-sectional area isn't smaller than the input pipe).

stunned_monkey Wrote:Interesting choice of words there "before the platform can't handle it properly"

Well, he might have meant that it becomes unmanagable for casual drivers. For the purposes of this build 290ish bhp sounds ideal, because that's 'fast 80s turbo sports car' territory (above an Esprit SE but below a 911 turbo) and you could imagine Legend getting there after a bit more development (at least, in euro emissions spec). More than that would be moving away from what you could realistically have bought had turbo DeLorean production gone ahead.

[stunned_monkey]

JZD was trying to buy the Renault 2.5 turbo. The car could have had the same powerplant as wne into the GTA

[Starglider]

stunned_monkey Wrote:JZD was trying to buy the Renault 2.5 turbo. The car could have had the same powerplant as wne into the GTA

Maybe, but this car comes from a timeline where Legend stayed on board, at least for the twin turbo. Although we have to assume alternate universe Martin G got hold of it in the early 2000s and replaced the K-Jet with EFI

[Guinney1971]

lol, someone stick some plutonium in Luke's BTTF car, lets go back to 1982, save the factory
and see what would have really happened

[stunned_monkey]

Guinney1971 Wrote:have to say, I'm not a fan of that exhaust tip on the black car

You should see the rest of it.... :roll: :lol:

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