Dont laugh-but my 2.5NA 'performance' project

[Turbocharger]

I ran Lucas Pintle (ex-Peugeot XUD9) injectors in place of the standard Pintaux injectors in my 2.25D - they don't have an auxiliary spray hole pointing at the heater plug. The penalty is poorer cold starting, but with smoothed ports, a 2.5NAD cam and the injection timing advanced until it rattled like there was a small construction project going on inside it would outrun a standard 2.5NAD Ninety.

For context, we're not talking Testarossa vs 911RS3 territory, but I learned plenty from it!

[cackshifter]

I'd be tempted to get it balanced, as it is likely to be revved, and it definitely makes for a smoother engine; also maybe a lighter or lightened flywheel if possible (no more powere but more responsive)?

Nigel

[need4speed]

If it keeps you amused then go for it, although I'm sure people will be curious about why you're doing this as it makes very little sense from a time/effort/money Vs performance gain point of view

What about propane injection?

Allow me this time Fridge.....

[RustyNissanPrairie]

fitted new head last weekend-trouble is piston/bores are quite worn-you can see down the back of #4 piston and see the top ring quite clearly, also a bit of movement between piston and bore when cold. Fitted new head anyway-its my daily driver and ring blow by isnt too bad. Turned fuelling up by 2 turns-still hardly smoking so perhaps more to do? but oil temp is up slightly, water temp is normal. Did 200 miles today pulls far better even with worn bottom end-holDs gear longer on hills-not Tdi level but not bad.

[Turbocharger]

Do you want to do any work beyond winding up the injector pump, or are you just asking a hypothetical question? If you're serious about making more power, you need to look at the rest of the engine first to make sure you won't be playing catch-the-piston. Sort the bearings, bores and rings to give yourself a solid base. Reliability is below the head gasket, performance is above it.

Then look at how to get more air into the engine, because fuel's easy to match up to it. Taking the rough casting flash off the ports is a good start, match the manifolds to the heads to maximise the area and avoid a sudden step, get the Pintle injector nozzles. Tidy up the inlet system for a short, smooth pipe to cold air, and get the exhaust flowing as nicely as possible. An infra-red camera could help to show you any hot spots to direct your work. Maybe swing the timing a little or even up the compression ratio with a head skim, but it's getting more 'developmental' now. From there, you have to decide what you're aiming for. If you want a tidy 2.5NAD that pulls well, I reckon that's about it. Going from 'developmental' to 'mental', you could supercharge it, add LPG, nitrous, water injection or the obvious route - a turbo - but you're back to needing a stronger bottom end to handle it all. The 19J engine taught us that much!

[RustyNissanPrairie]

not 100% sure where Im heading with this engine to be honest-(its a long story) but one of the reasons for fitting the head last weekend was to see how much gain or improvement it gave to the engine irrespective of the bottom end. If it gave a noticeable gain then I would stand to have that gain PLUS the gain from a (Turner engineering) rebuilt bottom end, and end up with a reliable (no turbo, or aluminium head, or leaky 'p' gasket etc of a 300tdi) engine that would chug along for another twenty years.

The trouble is though-it looks like the gains from the head are at the expense of increased oil temps (water is the same temp as before)-more air+more fuel=higher temps. I know these arnt ideal for a N/A fitted with hotspots-they crack and can&will fall into the barrel=wrecked engine&head-the weak spot of a N/A.

The other thing is im being swayed by a 300tdi seeing as my LT77 has mainshaft wear and I want to galv chassis it anyway so I might as well order a chassis with 300tdi mounts, 'upgrade' a recon box to a R380 from Ashcrofts, and source an ex-Disco low mileage 300tdi for less than a bottom end rebuild on my N/A........

[Quagmire]

Whilst replacing a coil on my girlfriends '52 plate Polo the other day I noticed that the alternator seems to have a clutch and spends most of its time idle, kicking in only occasionally. The pulley would be whizzinig round, but the windings you could see were stationary.

If we are taking the same approach to power on this as Honda did when applying weight savings to the NSX then might be worth a go?

Don't ask me for a circuit to monitor and trigger such a thing though...

Should be more insurance friendly too.

[RustyNissanPrairie]

Okay-bit of an update;

Tried a set of Peugeot non Pintaux injectors (FOC through a friend), a very slight improvement at mid to high revs BUT could have just been because of fitting new clean injectors as opposed to the 2 year old Pintaux types that I took out. Starting was okay initially but after a week or so it got harder to start-it took a lot more cranking and then obviously quite a bit of grey unburt diesel smoke till it cleaned up. Took them out and went back to a refurbished set of standard injectors again. Probably ok in a warmer climate or if I'd fitted some Bosch Duratherm glowplugs as well but otherwise not worth bothering with.

The 2nd biggest difference though (after fitting the gas flowed head) was fitting a Donaldson air filter. These are available cheap on Ebay (and I've got the mounting bands for sale on here). Basically they are a far bigger airbox & filter that were fitted to 300tdi/Wolfs serving in Iraq to cope with the dust levels there.

It flows a lot more air than the standard N/A (or 300tdi) filter and has given an approx 5mph increase up my usual test hills-low to mid range torque has improved by quite a bit as well. Not sure if they would work so well with a standard N/A cylinder head, due to the fact mine is gas flowed/ported and so can breathe more air in and out than a standard head and was possibly being restricted by the standard air box

Requires an adaptor making up to go from the reduced bore of the N/A inlet manifold hose to the increased bore of the 300tdi/Donaldson airbox outlet.

In my case-definitely worth the £20 odd quid they cost.

Also trying 2 stroke oil in the diesel. Theory seems to stem from South Africa where they have sulphur issues with their diesel-it probably only effects newer state of the art diesel systems as opposed to older mechanical setups. Anyway, adding 2 stroke oil is supposed to add lubrication to the injection system, which leads to reduced friction levels in the IP resulting in increased engine power outputs.

Will report back.

[lynall]

Guy on the series 2 forum has a very sexy 4 branch manifold and complete stainless diesel ex system for sale its in the classified section.

Lynall