Boost gauge install

[SiberianPatrol]

Had a guy install my boost gauge and I'm wondering if he tapped into the right place for a reading. He tapped a thread into the intake manifold just past the turbo. This seemed a bit odd but he was insistent that that was the best location to pick up the boost. I thought you simply picked it up from the vacuum line running from the injector pump to the turbo?

Can someone clear this up for me? Did he do it right or do I need to tee into the vacuum hose? Here's the picture of what he did and the instructions for the gauge install.

http://www.nissanpatrol.com.au/forums/images/imported/2015/10/312.jpghttp://www.nissanpatrol.com.au/forums/images/imported/2015/10/313.jpg

[threedogs]

Which engine do you have again??

[SiberianPatrol]

Mine is the RD28Ti in a 99 GU.

[threedogs]

not familiar with that motor , but if its on the boost side why not.
On my mighty ZD30 they drilled and tapped a hole under the ic.
Im changing that to a plate that fits under the OE boost sensor
neater imo
Heat that tubing up in a cup of hot water , you'll be able to push it on further
maybe even use small cable ties

[SiberianPatrol]

not familiar with that motor , but if its on the boost side why not.
On my mighty ZD30 they drilled and tapped a hole under the ic.
Im changing that to a plate that fits under the OE boost sensor
neater imo
Heat that tubing up in a cup of hot water , you'll be able to push it on further
maybe even use small cable ties

I'll be taking it for a drive today when he's done to see if it works right. If it doesn't, I'll cap off that hole and tee into the vacuum hose. Does you boost gauge register when you just rev the engine or do you have to be driving it under load to get an accurate reading?

[SiberianPatrol]

Took it for a drive around the city and it sits around 5psi accelerating about 1/2 throttle. If I really punch it, it jumps to 9.5-10psi. Haven't taken it out on the highway yet because I need to replace my front hub seals. Does this seem like it's reading the right boost #s for the 2.8?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[JoeG]

Sounds right
Light load should be around 3 to 5 psi full load and say over 2,000 rpm then 8 to 10 psi
so looks good
regards
Joe

[SiberianPatrol]

Sounds right
Light load should be around 3 to 5 psi full load and say over 2,000 rpm then 8 to 10 psi
so looks good
regards
Joe

Thanks, Joe. Since everything is mechanical on the 2.8, am I correct in assuming that there isn't any way to increase the boost since it is vacuum controlled and not controlled by the ECU?


1999 GU RD28Ti turbo diesel; manual transmission; 33" Khumo mudders; ... more mods on the way ;)

[JoeG]

Ther is no way to increase the light load boost as that is a function of exhaust gas flow.
However the boost at full load and higher gas flows can be controlled by a variable restrictor.
typicaly a Daws valve and needle valve.
do a search on this and think about it.
Regards
Joe

[SiberianPatrol]

Ther is no way to increase the light load boost as that is a function of exhaust gas flow.
However the boost at full load and higher gas flows can be controlled by a variable restrictor.
typicaly a Daws valve and needle valve.
do a search on this and think about it.
Regards
Joe

Thanks again, Joe. I have a Dawes valve that I was going to install but it wasn't making much sense as to how it worked to increase boost. Need to do some more research. There's not much chance of boost spiking so I don't need to restrict the boost. Just didn't know if I could increase it by a couple of points.

[SiberianPatrol]

Can anyone tell me what a safe boost range would be for the 2.8? I have stock intake and exhaust and won't be changing those out anytime soon. Is it worth trying to tweak the boost on a stock setup or wait until the snorkel and exhaust get fitted?

[JoeG]

Just increasing the boost only increases air flow which will reduce smoke and give a cleaner burn but not much more.
You need a free flowing exhaust and more fuel to go with the increased air flow for more power.
a free flowing exhaust should result in slightly higher air flow throughout the load range (turbo spinning up quicker)
However there come the point of diminishing returns when more air means higher air temp and no more gain, so a better air intercooler cooler adresses that
and possibly more power sooner, you can spend lots for little gain.
If you plan to do a lot of high load running (towing of heavy loads) then the cost can be apreciated as economy improves (less smoke more complete burn fuel drive vehicle not just up in smoke)
Joe

[SiberianPatrol]

Just increasing the boost only increases air flow which will reduce smoke and give a cleaner burn but not much more.
You need a free flowing exhaust and more fuel to go with the increased air flow for more power.
a free flowing exhaust should result in slightly higher air flow throughout the load range (turbo spinning up quicker)
However there come the point of diminishing returns when more air means higher air temp and no more gain, so a better air intercooler cooler adresses that
and possibly more power sooner, you can spend lots for little gain.
If you plan to do a lot of high load running (towing of heavy loads) then the cost can be apreciated as economy improves (less smoke more complete burn fuel drive vehicle not just up in smoke)
Joe

Thanks again, Joe. As have switched over to a mechanical injector pump, winding a little more fuel to it won't be a problem. It already runs a bit on the rich side, so I might wind a little more boost for a better burn and see what that does. Not trying to make a race car here, just want the ol' engine to run as efficiently as possible to prevent problems down the road.