NissanDiesel Forums

Boost compensator is definitely required. Without it either the pump would be always under fueling on boost or set to over fuel all the time(except at max boost)

Under-fuelling is fine (though you don't get maximum power) and should (in theory) reduce EGT over NA. Over-fuelling isn't so good

So . . . boost compensation isn't necessary -- unless you want more power and to retain durability

Remember, I'm adding a turbo to an LD28 (and member dslsmoke has done that too) and will not be changing fuelling (initially). I'll be adding the EGT gauge of course.

well then..there is not point in turboing it.if you are going to leave fueling alone..no power increase.no point..just more strain on head gasket..

now increase the fueling,thats a different story!!

so ip needs to have boost/fueling compensation!!! if it didnt manufactors would not bother with it..now would they?

remember i have turboed my sd33..

philip wrote:

dieselscout80 wrote:I don't think you need the boost compensator to run the turbo (the boost compensator keeps the engine from smoking in low boost conditions and then when boost is built up it adds fuel for more power) Snip

Carey

Carey: Looks like "you don't need a boost compensator" is in conflict with "boost compensator keeps engine from smoking in low boost conditions".

So to take best advantage, boost compensation is necessary to control exhaust smoke, power output, and of course exhaust temperatures.

It is if you require no smoke during low boost, but many diesels have been built that do not have a boost compensator and yes they do smoke till the turbo builds boost. Most NA diesels will smoke too the SD's with the MZ are one of the few that don't smoke.

Can it be ran without a boost compensator yes, but that is not the best way. Now days the greenies will take a strong dislike to the smoke too.

If I ever turbo my Tug SD33 I still have my SD33T pump to help make that swap.

Carey

zen wrote:well then..there is not point in turboing it.if you are going to leave fueling alone..no power increase.no point..

My primary goal on my LD28 turbo project isn't more power -- it's less visible smoke. If more power and better mileage comes along with that, those are side benefits. I will probably be adding boost compensation in future, and that mod's goal is for more power, but Stage 1 is: same power as NA + less visible smoke.

I understand that others have different goals -- I'm pointing out that boost compensation is not necessary -- if you don't add more fuel.

zen wrote:well then..there is not point in turboing it.if you are going to leave fueling alone..no power increase.no point..just more strain on head gasket..

now increase the fueling,thats a different story!!

so ip needs to have boost/fueling compensation!!! if it didnt manufactors would not bother with it..now would they?

VW put a turbo on the 1.6 and 1.9 IDI engines without increasing fuel and imported them to the US (91-92) and Canada (91-95+). Advertised HP was up from the NA diesel 52hp to 59hp, so some manufacturers did do it.

sa

glenlloyd wrote:VW put a turbo on the 1.6 and 1.9 IDI engines without increasing fuel and imported them to the US (91-92) and Canada (91-95+). Advertised HP was up from the NA diesel 52hp to 59hp, so some manufacturers did do it.

I didn't know that. 7 HP is approx. the amount I'd expect to pick up from the reduced pumping losses that are compensated by the turbo.

ISUZU 4BDI[3.9] fitted to australian landrovers comes in 2 turbo versions.

1Garret air research turbo with waist gate overboost relief valve and boost compensation.
2 IHI turbo with no waist gate and fuel delay timmer on the back of the IP.

the latter is for low tech military aplication but has better performace.

IHI tractor we have on the farm is the same.it has a rotary IP that is electrically switched like the VE-but by design it has a shut down idle mode for a few seconds.I believe the delay function is used to dampen fuel quantity changes.

glenlloyd wrote:VW put a turbo on the 1.6 and 1.9 IDI engines without increasing fuel and imported them to the US (91-92) and Canada (91-95+). Advertised HP was up from the NA diesel 52hp to 59hp, so some manufacturers did do it.

sa

In the interests of cost containment, one -could- "curve" RPM/Load fuel delivery to a turbo that provided boost over a narrow range (no boost compensation). But when anticipated boost was short of expectations ... smoke. Surely a crude and vulnerable but cheaper design that gave way when the Environmental Protection Agency got involved.

Also, the VW had no air throttling / pneumatic governor such as found on many SD engines. Is that correct? That's another factor in optimal fuel delivery.

In legitimate SD33-T engines, which IP was fitted?

philip wrote:In legitimate SD33-T engines, which IP was fitted?

I was curious if a rotary IP was also used in conjuntion with factory turbocharging.

Can't really call the above IP a fully mechanical pump because there is also mixture override based on boost pressure. A diaphragm still influences fuel rack position.

philip wrote:I was curious if a rotary IP was also used in conjuntion with factory turbocharging.

Possibly on the newer ones? Not on the 1980 Scout.

ebay number 200029776295

davehoos wrote:ebay number 200029776295 -SNIP

So Dave, this is a 1985 Nissan Patrol SD33T. I see it has an aneroid valve positioned horizontally off the rear of the governor housing.

The engine appears to have a spin-on coolant filter adaptor (no filter present). AU accessory?

philip wrote:this is a 1985 Nissan Patrol SD33T.

Maybe not. The Seller states that he bought it for a 1985 MQ.

I see it has an aneroid valve positioned horizontally off the rear of the governor housing.

Looks like a accel prop to me.

The engine appears to have a spin-on coolant filter adaptor (no filter present). AU accessory?

Looks like the Secondary fuel filter mounting base to me.