Bongo TD Tuning Parts -interest?

[rustyp]

Hello there,

I am considering having some Thermal Heatshield Inlet Manifold Gaskets made up.

They are CNC made from 4mm plastic to prevent heat being transfered from the head to the inlet manifold to keep the air entering the engine cooler/denser. Put your hand on the inlet manifold when it has been running and it get very hot.

The heatshield gasket is best used in conjunction when the EGR pipe is removed and blanked off as this also adds a lot of heat to the inlet manifold.

I would need to make a bulk order to make it cost effective. I am also considering having EGR removal kits made up. Would anyone out there be interested in either

a) Heatshield Gasket
b) Heatshield Gasket & EGR delete kit

I am not sure of prices as yet but I would hope not that much more than a standard inlet manifold gasket (I last paid £15 in a bongo specialist shop for one) the EGR delete kit will be similar.

and finally.....

The runners of the inlet manifold are smaller than the head restricting flow into the head. I have opened up and matched the ports to the head on my inlet manifold. Would others be interested in this service on an exchange basis?

All the best, Russ

[Driver+Passengers]

I'd wondered about this myself after having come across similar for other vehicles. I'd also wondered about adding a heatsink with fins to the threaded bolt holes on the other side of the head (some heads) to contribute to air cooling. Anyway, that's something else entirely.

I'll be interested to see what others think, too. Someone I was talking to (I forget who) mentioned a possible drawback of changing the heat distribution in the head - by isolating the inlet manifold you're reducing the thermal mass on the inlet side. This may (perhaps) speed up head failure in the event of an overheat, but it's difficult to say...

[rustyp]

The inlet manifold being a heat-sink is a good point but the air entering the head would be cooler which would potentially offset this?

I have some other ideas in the pipeline which would help keep the head cool but I'm keeping them under wraps at the moment awaiting time for me to fit them

Russ

[Northern Bongolow]

all sounds interesting stuff. .
i think it was you that was making an improved aftercooler, how did that go.
would bolt on fins not improve the temp of the inlet manifold. maybe a water jacket manifold like on the marine stuff.
how do you plan to remove /blank the outlet on the exhaust manifold as this nut is really bad to remove.

just removed my egr, and opened up the crankcase/top end breather to atmosphere, the improvement in performance is very noticeable, just need to get past the mot man with my crankcase pipe strapped to the sump venting oil laden vapours.


edit, beaten to the fins by matt.

[Driver+Passengers]

I hadn't thought about fins/additional cooling for the inlet manifold. Isolating it perhaps makes more sense, I think. Unless you want to increase thermal mass and surface area.

Perhaps we're taking it too far. A heat-resistant inlet manifold gasket on its own is an interesting idea, worth playing out...?

[Driver+Passengers]

i think it was you that was making an improved aftercooler...

Yes... viewtopic.php?f=3&t=38190. What's the lastest?

[rustyp]

Frustratingly I have now got all the parts ready for the chargecooler conversion, it is very impressive if I do say so myself, but my day job means I have been working lots of Saturdays grrrr, which has meant less family time so I haven't been able to commandeer my brother's workshop as would need to fit in a day, drive in/out, the Bongo being our only means of transport!

The chargecooler is an intercooler with a water jacket

The nut on the exhaust manifold is a real b#£%&&d and doesn't always undo (mine didn't) so with the delete kit I would have the choice of a blanking plug if the nut undoes or a blanking plate where the EGR diaphragm is and another blanking plate on the inlet manifold "elbow" so the egr pipe on top of the inlet manifold can be removed reducing heat transfer.

I eventually removed my exhaust manifold, cut off the egr pipe crimped it and had it welded shut

[briwy]

Interesting theory.

Assuming you can get a cooler charge of air into the engine than this will deliver more air as you say. However, will the fuelling system automatically take care of the extra fuel needed to keep the fuel/air ratio correct? If it won't then the mixture will end up weaker which in turn can produce more heat. I don't know if this is so critical in a diesel but when I used to play around with turbocharged petrol units it certainly was, a too weak mixture usually led to burning out valves and valve seats and in bad cases cracked heads. A favourite easy tweak on the first Saab Turbos was to screw the wastegate pressure up but a lot of people didn't alter the fuelling which led to a lot of failures.

Will insulating the inlet manifold from the head make much difference. I guess without some serious measurement it's difficult to know how much heat the manifold is taking from the head as opposed from the hot compressed air coming in. I know it passes through the intercooler but that is fairly small on the Bongo. Is the inlet pipe into the manifold hot?

Has opening up the inlet manifold made any difference? If the system is already delivering as much air as the engine needs to run then it shouldn't really show any improvement.

[Northern Bongolow]

keep us posted please. .

my nut took lots of heat and some 18 inch stillies and a 2 foot scaffolding pole. .
if it cannot be removed you could use a plumbers fitting on the pipe as its 22mm od.
i removed the tube over the top of the inlet manifold for the same reasons, remove heat.

[rustyp]

Hi Briwy et al,

I'll try to be brief. Diesels actually run hotter with richer fuelling as it is slow burning and the black smoke you see is fuel that hasn't burnt during combustion either due to too much fuel or too large fuel droplets (dirty/worn injectors). This fuel that carries on burning is quite hot.

At tickover diesels run at about 50:1 air to diesel, very lean, when you press the accelerator more fuel is added to richen it up, this creates more heat in the exhaust gasses spinning up the turbo which adds more air and so the boost pressure pushes down the diaphragm on the fuel pump adding more diesel. Maximum power (before smoke is produced) is about 22:1-20:1

Simply put to make more power add more air and/or more fuel. Getting more air into the engine should help with efficiency (as does removing the EGR) and anabling it to run cooler.

The intercooler is woefully small, it makes a real difference running in sub-zero temperatures. The charge pipework is far too long and convoluted. Project Chargecooler will remedy this.

The inlet manifold plenum is woefully small because of packaging issues. I plan to look at this in the future. Anybody here work in a metal stockholders?

With the heatshield gaskets, on a CRX engine with one fitted you can comfortably place your hand on the inlet manifold when previously it was too hot.

Will be doing final back to back test on inlet manifold soon now I have some new carbide burrs

All the best

Russ

[briwy]

Hi rusty.

Thanks for that, explains it well. If I understand correctly then the system will automatically provide more fuel with more boost pressure from the turbo as the fuelling iis (at least partly) dependent on the boost pressure. This was my concern after my experiences with petrol engines.
Does the Bongo ECU come into this somewhere?? My Bongo is drive by wire so might be different.
I too was surprised at the small size of the Bongo intercooler and had intended at some stage to try a bigger one which I have lying around somewhere.
My concern now is that fitting the bigger intercooler will get more air into the engine (as its cooling air which has already passed through the turbo) with the same boost pressure that the standard Bongo intercooler would, is that right? If the boost pressure is the same then the pump won't see a need to put more fuel in and the mixture will still be wrong. Or have I got this wrong somewhere?

Do the inlet manifold studs line the ports up spot with the head? When I used to modify heads /manifolds we used to line them up accurately by drilling through both and inserting a dowel. Even a slight bit of misalignment would negate any improvements to the ports.

I'd certainly be interested in the gasket and the intercooler setup. Anything to get more mpg is worth it nowadays.

[rustyp]

The inlet manifold runners are much smaller than the ports so I open the runners up to match the gasket which matches the ports. The difficult thing is the runners are curved and all but 2 are paired up, where the runners meet the plenum I increase the height of the runners to blend into the plenum. The studs hold the inlet manifold well so no need for dowelling.

Fuel/air ratio isn't at all critical on diesel until you get too rich. Cooler/denser air will simply improve combustion/power. On a really cold sub-zero day the torque improves greatly.

Russ

[briwy]

OK cheers russ.

All good news then

[Simon Jones]

It would be useful to get it on a dyno for some before and after stats.

[scanner]

Fuel/air ratio isn't at all critical on diesel until you get too rich.

Fuel/air ratio on a diesel is what determines your speed.

No fuel = stopped
more fuel = more revs = faster.

The air inlet is wide open all the time as there is no butterfly valve as on a petrol and all you do to go faster is add more fuel and add it at the right time. Add too much at the wrong time or without enough oxygen (not enough air) and all you get is black smoke.

More air (or cooler, denser air and thus more oxygen) allows you to burn more fuel to produce more power