The Racetractor. The End.

[Lwilliams]

[7057sam]

No need to get the popcorn out,Ruan wins everytime

[Ruan]

Or just use it as it is because its fine

OK ignore me, I provided a valid argument, but apparently it's fine.. 

[fatlapit]

It is fine been using this rad for 2 years no problems

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As in just use the rad only and not the expansion bottle

[Ruan]

It's a different engine with a differently designed cooling system which doesn't suffer the same problems as the XUD cooling system, hence my 2 paragraph response, trying to explain why it's not ideal doing that.

But as said, these are merely my opinions, people can take them or leave them.

[fatlapit]

I totally agree ruan but theory is different to practice and actually using it there are no problems

[Ruan]

I think I've said what I need to say - I've made my points clear I hope.

The practice is fine on one engine, but you can't apply the same to another engine of entirely different design.

[fatlapit]

What is so special about this cinfiguration of engine to any other xu engine?

[Lwilliams]

Only thing I would like to ask is if water is being sucked from the bottom rad hose how does it airlock? I could see why if it was taken from the top as it would just take in air... what am I missing?

Basically what I'm asking how does it air lock and why is it different for a xud and not a gti 6?

[Matt-Rallye]

Only thing I would like to ask is if water is being sucked from the bottom rad hose how does it airlock? I could see why if it was taken from the top as it would just take in air... what am I missing?

Basically what I'm asking how does it air lock and why is it different for a xud and not a gti 6?

This is why ruan said to use the lower hose rather than the top to avoid this airlock situation

XUD9TE and XU10J4RS is a completely different cylinder head, with the XU10 being much more efficient in regards to cooling.

Cannot even compare them tbh.

[Lwilliams]

Ruan didn't actually say that it would avoid it he just said use the lower to tee off for the expansion... Sorry piggy will stop posting on your project now

[fatlapit]

Aye sorry piggy

[Ruan]

XUD9 vs XU10 - they're a totally different cylinder head with a totally different type of combustion process with totally different thermal loads in totally different places. The XU10 is no more efficient/inefficient than an XUD - it's just that the designs of them are so vastly different, you cannot compare.

XUD9 the fuel is burning in a small chamber in the cylinder head, which rushes past an orifice in an Inconel chamber, this Inconel begins to crack on older or abused engines, that's how hot it gets, I've also seen the aluminium around where the prechamber cap meets the cylinder head melt and bow out - this is where the vast quantity of heat is generated within an XUD engine. It then rushes out as it burns onto the crown of the piston - at the time it was the best compromise of noise and emissions - DI couldn't compare until the late ninties where computer modelling could be used to make DI quiet and pass emissions.

This means that the vast quantity of heat is generated within the cylinder head, this is why they require a constant flow of water through the head to prevent hot spots whilst warming up and the thermostat is closed. This is part of the reason that the XUD is quite sensitive to cooling system changes, if the flow around the cylinder head is messed up before the thermostat is open, it will boil off the water locally around the precombustion chambers (nucleate boiling) because there's only so much convection within the coolant going on, the amount of heat quickly produced can't be dealt with so it boils, then you will damage the cylinder head before the thermostat even opened because there was no water flow.

XU10 by comparison the fuel burns in the area between the piston and the cylinder head - this means that the way the heat is transferred to the cylinder head is very different, the XU10 requires much more cooling in the block due to the lower compression ratio used and therefore decreased thermal efficiency (more compressed gas = more insulation = less heat transfer) - they transfer more to the block and around the exhaust ports. This is the reason a GTi6 on idle will have the heaters blowing red hot whereas an XUD idling on a cold day, you can easily turn on the heaters and remove all the heat to the point the blowers go cold - because unless there's large quantities of fuel injected, the quantity of heat transfer is actually very low, but incredibly localised.

If you take the DW10 for example, ALL of the fuel is burned in the piston bowl with a high compression ratio. They have incredible thermal efficiency to the point where they have glowplugs in the coolant system to make them heat up! You can leave a DW10 engine idle all day with basically no cooling because they're so efficient, they so rarely need fans!

In terms of the bleeding problem, this is because of the internal passages inside the XUD9 cylinder head - it's a design that is fine if you read the manual before you work on it, unfortunately, people ended up bleeding them "like any other car" and ended up with air locks, which consequently blew the head gasket, then people installed a fibre head gasket and boom, you've a reputation for an engine that blows head gaskets. An XU10 or almost any other XU or TU based engine doesn't suffer this problem anywhere nearly as bad, they don't have nearly as complicated cooling system setup. The XUD cooling system was so problematic, it got changed about 5 times whilst in the 306, with varying different layouts and revisions - all in an attempt to solve the problems of the ways the heat transfer happens inside the cylinder head and the air locking that can happen.

This is why on the Ph2 cars they went to an external header tank which you can remove quite easily and cause to be the highest point in the system. If you have a radiator like suggested and don't have an expansion tank, the problem is immediately exacerbated since the bleed line has to go to the top of the radiator, but the top of the radiator could have air in it since the system pulls back when the pressure drops again - the air will then move to the highest point (inside the cylinder head...) and you've then airlocked the cylinder head - you know this when the water flow to the heater matrix stops due to the head being airlocked and the heaters suddenly go cold. By having an expansion tank, the pressure will simply raise to the correct point and drop again, no need for any overflowing, since the amount of air inside the top of the expansion tank will always maintain this pressure unless the pressure is exceeded, in which case the cap will release.

An XU10 won't do this because, simply due to the way it's designed, it instead actually moves any air into the heater matrix where it doesn't cause too much of a problem, but the air doesn't stop the water flowing through the head, unlike an XUD.

As said, please don't think I'm just being an arse for the sake of it, I'm trying to actually help - I'm using a bit of my own knowledge and a bit of science on this to prevent cockups. I've explained what I can.

I'll leave it so James can make his own decisions - I'm just trying to put the facts forward.

[Lwilliams]

Think I'm going to have to find you Ruan at some point and buy you a beer

[Piggy]

haha!

sciences biatches.

Now bend over... ruan is in the house!


Don't strike through your post matey, keep that there, good info if anyone searches etc.


Consider that both Chris' gti5 and my xud11 are at a serious level of tuning respective to each engine design. Yet they both work very differently. To start with, ones a petrol and ones a diesel... so I can't really believe people are trying to compare their cooling systems.

I still genuinely believe that Chris' needs an overflow/header tank though tbh, either that or you are not running it topped up correctly/running a different designed 200SX rad.

Either way, I need and want to do it properly. Not just drash on. The xud/idi diesel is sensitive to temperatures...so I can't afford to mess it up.

I will order a barbed brass to go into the bottom of the rad as I will ALREADY have a T piece in the bottom hose for the heat exchanger to be plumbed in. Either that or put the heat exchanger into the bottom of the rad and the expansion tank on the bottom hose. Not decided yet. More bits yet to come from Mr Posty.

[Piggy]

https://www.youtube.com/watch?v=tZ-7oRJPt0o

[1616six]

Have you done much track time before?

I take it that's the SJCAM? I love mine.

[Piggy]

arrival from Germany...

[attachment=23991]

---

Have you done much track time before?

I take it that's the SJCAM? I love mine.

Done a little, not much, and some time ago. Why?

yup, Sj4000

[Poodle]

Good grief, does it always sound like that or is that where it was overheating so badly? Looks quick mind, be a lot quicker as you get more aggressive in the corners though.

[Piggy]

Good grief, does it always sound like that or is that where it was overheating so badly? Looks quick mind, be a lot quicker as you get more aggressive in the corners though.

When I really gun it you can here how sweet it is. Remember its a diesel!

Yeah my last session was much better, following ones like Sam and Sam I could see they could carry a lot more speed through some of the esses and camp than I thought was possible.

I was just working hard at getting braking points and turn in points as well as having my left eye on my gauges!

Not sure if it shows on those videos but a few times I pulled up so hard I had to accelerate into the corner coz I had scrubbed too much speed, the "reccomended" brake point cone I found was nearly twice the distance I needed on most corners

[Piggy]

everyone gets annoyed with things I say...but everyone loves pictures...


[attachment=24007][attachment=24008]

[darrenjlobb]

Im afraid im not sold on the bonnet.....Imo its kinda ruined the car a little bit...

I do genuinely have alot of respect for all the work that has gone into this, I can see how many hours of work have gone in, and its far more than likely meets the eye.

There are a few things I would have done differently, and a few things everyone else would have done differently, but thank god for that or else this would be a very boring forum, however I think some work is needed on the bonnet, I've never been a fan of any mismatching panels, but I think black on moonstone just looks even more odd for some reason...

[procta]

what colour is the bonnet getting painted? or is it getting a wrap?

[Danny Wideboy]

Nice dag.

[Piggy]

Im afraid im not sold on the bonnet.....Imo its kinda ruined the car a little bit...

I do genuinely have alot of respect for all the work that has gone into this, I can see how many hours of work have gone in, and its far more than likely meets the eye.

There are a few things I would have done differently, and a few things everyone else would have done differently, but thank god for that or else this would be a very boring forum, however I think some work is needed on the bonnet, I've never been a fan of any mismatching panels, but I think black on moonstone just looks even more odd for some reason...

It's not staying black fella...

But I aint going to paint it overnight!

Plus I aint going to paint it then hack at it for trimming and a NACA duct!!

---

what colour is the bonnet getting painted? or is it getting a wrap?

either wrapped or painted.

Painted it be moonstone.

Wrapped, looking into a colour match as close as. But not sold on that yet.

[tonycox_design]

Moonstone is not an easy colour to match too. For perfection you'll have to respray. Perosnally I'd go for a contrast colour but that's me. I'll try and find a match 2moro!

[Piggy]

my track effort:

   

[Poodle]

I'm aware it's a diesel lol, still sounds awfully rough, even for an xud. Maybe it's just the camera or the chronic stripping, but it's something i've noticed before on your vids, more so than with other stripped diesels... I can hear it's making good power, not sure i'd term it as "sweet" though. As long as you like it, who cares!

Haha yeah, those first few track outings are a bit fraught, trying to watch everything at once while gettimg good laps in is harder than it looks. Good effort on those tyres!

[Dum-Dum]

They do sound rougher but also smoother than the HDi's and XUD9s but it's a good sound

[darrenjlobb]

I'm aware it's a diesel lol, still sounds awfully rough, even for an xud. Maybe it's just the camera or the chronic stripping, but it's something i've noticed before on your vids, more so than with other stripped diesels... I can hear it's making good power, not sure i'd term it as "sweet" though. As long as you like it, who cares!

Haha yeah, those first few track outings are a bit fraught, trying to watch everything at once while gettimg good laps in is harder than it looks. Good effort on those tyres!

What are you rambling on about?!

Are you just referring to a bit of diesel knock midrange / mid load ? Its a 200+hp diesel fueled by a VE....Its impossible to make a timing curve suit a motor with that much top end in a VE... Sounds crisp on the blower just as it should.

Besides, who can call themself's a diesel fan if they dont like the sound of a diesel running some timing!