Outer Limits 4x4 Board

well i have recently discovered that i have blown the factory turbo on my rd28t (gq model), so im stuck with wat to do. now before any one says put a v8 in it, i cant im on my P's. or put a 4.2 in it, i aint got that kinda money.
so it would seem im up for a new turbo, id like to put a gt28 on it but i get confused by all the .64 .86 turbine and stuff like that. so basicly wat i want is something that comes on to boost as early a possible and continues to around the 3500rpm mark as i am lookn for as much torque as possible and i really cant care about top end. so wat sort of turbo should i be lookn at?

as well i have heard of modifying the boost compensator for more low down torque. wat exactly is involved with this?

thanks
Mundy

get a price on getting you old one rebuilt and hi-flowed. this will give you boost earlier and not lose any top end if yours is rebuildable. used to cost around a 1000 bucks when i was toying with turbo rotories.
you don't have to worry about different manifolds or pipework or anything.

Go to ebay, buy a rebuild kit and install it.

Unless your turbine shaft is rooted that'll get you back up and running.

A T28 is too big for a 2.8. Don't get it "high flowed", that's only for ricers and won't help a diesel.

for around a 1000 i can get a new turbo, so thats why i would rather upgrade my current turbo but im not sure wat turbo would suit my application

mundy wrote:for around a 1000 i can get a new turbo, so thats why i would rather upgrade my current turbo but im not sure wat turbo would suit my application

Your current turbo is probably the best match. What do you want to "upgrade" to.
A worthy upgrade would be a ball bearing turbo of similar size to your current one (GT25 maybe). But you won't get one for $1000.

mundy wrote:for around a 1000 i can get a new turbo, so thats why i would rather upgrade my current turbo but im not sure wat turbo would suit my application

Looking at the USA diesel mags for stuff about this, hard to say really.

As they sell mainly larger size turbo's that have a larger exhuast outlet this helps to reduce EGT's and the shoot on effect is it helps to spin up the turbo faster, these are also on V8 7litre diesels though.

probably doing what the other guy said get the same turbo and high-flow it, would be doing the same thing and tell the poeple that your mainly after low end speed.

Some else to know is that on a diesel once the turbo is spinning, it'll usually keep on spinning as the air being sucked in on the compressor side will help to keep the xhuast side spinning so helps to suck out the exhuast gas out of the engine.

One thing I do know what ever works on petrol engines turbo wise doesn't always apply to diesel engine turbo wise, so I would say goto a diesel shop and ask them about what to do about the turbo rather than hit up petrol turbo shops.

zagan wrote: As they sell mainly larger size turbo's that have a larger exhuast outlet this helps to reduce EGT's and the shoot on effect is it helps to spin up the turbo faster, these are also on V8 7litre diesels though.

You've got that backwards.
A smaller turbo housing will boost higher, spin earlier and lower EGT's.
A larger turbo housing will boost less, spin up later, have higher EGT's but give more topend power.

I've been told a disco potato, check this link out

http://www.horsepowerinabox.com/HPIAB2/category12_1.htm

There's also a good thread in the nissan tech section at the mo'

mattstar wrote:I've been told a disco potato, check this link out

http://www.horsepowerinabox.com/HPIAB2/category12_1.htm

There's also a good thread in the nissan tech section at the mo'

No way.
All of the turbos on that page are way too big for a 2.8L diesel.

i went through this with mine also...

after much messing around i purchased a brand newy from mtq.. $1500..

nearly every other turbo you will fit has a different manifold latout, so you will either have to make a adaptor or a complete manifold..


there is a used unit on ebay (search under nissan patrol gu) for $250...

id go this way bud, lot less mucking around..

KiwiBacon wrote:Go to ebay, buy a rebuild kit and install it.

Unless your turbine shaft is rooted that'll get you back up and running.

A T28 is too big for a 2.8. Don't get it "high flowed", that's only for ricers and won't help a diesel.

hey kiwibacon, i'm curious, from my knowledge a hi-flow turbo will increase performance no matter what the application, they spool up to full boost earlier, less lag and hold boost better for top end (not that a deisel has much top end rpm)- why doesn't it advantage a deisel ??? I don't see the logic ??

A high flowed turbo will not improve spool up. They flow with less restiction, so in relation to spool up they will behave like a (slightly) bigger turbo - raising the boost threshold.

Steve.

brown hornet wrote:

KiwiBacon wrote:Go to ebay, buy a rebuild kit and install it.

Unless your turbine shaft is rooted that'll get you back up and running.

A T28 is too big for a 2.8. Don't get it "high flowed", that's only for ricers and won't help a diesel.

hey kiwibacon, i'm curious, from my knowledge a hi-flow turbo will increase performance no matter what the application, they spool up to full boost earlier, less lag and hold boost better for top end (not that a deisel has much top end rpm)- why doesn't it advantage a deisel ??? I don't see the logic ??

Diesels don't need high flow, they need high pressure. The modifications made to a turbo to let it deliver higher flow (i.e. bigger A/R exhaust, bigger trim compressor wheel) result in less low end torque and can surge when you try to get full boost at low rpm.

If there was no downside to modifying a turbo that way, then they'd all be done from the factory. Often people selling a product or service will deny that downsides exist. But they always do.

Thanks Kiwibacon, I tried writing that but it didn't come out right.

Steve.

thanks kiwibacon

Happy to help.

BTW a T28 would be a good match for the 4.2L diesel, so if you have your heart set on one, get the engine to match.

KiwiBacon wrote: Diesels don't need high flow, they need high pressure. The modifications made to a turbo to let it deliver higher flow (i.e. bigger A/R exhaust, bigger trim compressor wheel) result in less low end torque and can surge when you try to get full boost at low rpm.

If there was no downside to modifying a turbo that way, then they'd all be done from the factory. Often people selling a product or service will deny that downsides exist. But they always do.

A good question for you:

Why is it that every 3rd party turbo over in the US is high flowed for a diesel?

zagan wrote: A good question for you:

Why is it that every 3rd party turbo over in the US is high flowed for a diesel?

Because they sell their turbo kits on "dyno power", not drivability. So rednecks can stand around wanking about how much power their truck produces.

Check out some of the promotional videos and you'll understand. Like a 15m long dodge doing donuts and blowing out soo much black smoke that you can barely see it.

I got a GT25 with the same specs as the standard turbo and it works great.
Cost $1300 with the custom housings and all brand new.

Comp AR .48

Exh AR .48

stool wrote:I got a GT25 with the same specs as the standard turbo and it works great.
Cost $1300 with the custom housings and all brand new.

Comp AR .48

Exh AR .48

Nice, is it ball bearing?

The banks website has this:

The air throttle in a gasoline engine will create a pumping restriction for the intake cycle of the engine whenever the throttle is partially closed. Consequently, under partial throttle conditions, the majority of pumping efficiency gains for gasoline engines come from exhaust flow improvements. Things in the intake system, such as air cleaner capacity and cool air induction, help most at wide open throttle, or nearly wide open throttle. An unimpeded exhaust path helps at all throttle openings.

Diesel engines, by comparison, have no air throttle. A turbo-diesel is free to intake as much air as it's intake conduits and turbocharger can supply for the load on the engine. A diesel is "fuel throttled", meaning its power output is regulated by how much fuel is injected. Therefore, all flow improvements in both the total intake and exhaust systems improve efficiency. Just as with gasoline engines, if pumping losses are reduced with flow enhancements, extra power is available to do work without extra fuel consumption.

zagan wrote:The banks website has this:

Therefore, all flow improvements in both the total intake and exhaust systems improve efficiency. Just as with gasoline engines, if pumping losses are reduced with flow enhancements, extra power is available to do work without extra fuel consumption.

BS.
Or rather, BS to sell their turbo kits. A bigger turbo is not "a flow improvement".

The extra boost a turbo creates increases the engines efficiency through two ways.
Firstly by increasing the dynamic compression ratio, secondly by feeding on energy that was wasted out the exhaust.

"High flowing" reduces boost at the engines most efficient operating points (low to mid rpm), hence it reduces the engines efficiency and increases fuel consumption.

Yes it increases top end power, but at the expense of your low and mid range torque, engine efficiency and drivability.

Their claim about "extra power without extra fuel consumption" is ridiculous.

Yes its a BB and will make 2psi at 1000 rpm under load

And 15psi by 2000rpm As I said it works wery well

zagan wrote:The banks website has this:, extra power is available to do work without extra fuel consumption.

WOW! I didn't know Banks sold hiclones!

I wonder if magnets on the fuel lines work on diesels?

There is no question that freeing up airflow can improve efficiency, but more HP takes more fuel. "Under the curve" (i.e at small throttle openings) better airflow can result in improvements, but this isn't actually "extra power" at all.

It's brilliant marketing speak though!

Steve.

Well to my mind Gale Banks has the runs on the board and is considered probably the finest aftermarket innovator of turbo's since the 70's.
As a case in point check out his "project sidewinder" Dodge, built to be the fastest pickup truck on the planet with a design brief of 20+ mpg capability and a top speed of 200+ mph.
It's an interesting read particularly the fact the vehicle had to drive to the Bonneville salt flats towing all their equipment as well. The tech info on the site and the way it was built is very interesting.
http://www.youtube.com/watch?v=E9eB4ilu_xQ
http://galebanks.com/sidewinder.cfm
Regards Andrew.

I wasn't having a go about the quality of his product - I have no doubt his gear is good - only that the way they expressed the effect of their product in that case is marketing BS.

Steve.

Therefore, all flow improvements in both the total intake and exhaust systems improve efficiency. Just as with gasoline engines, if pumping losses are reduced with flow enhancements, extra power is available to do work without extra fuel consumption.

Sounds fair to me...

All flow improvements improve efficiency.

If pumping losses are reduced with the above point - overall efficiency should increase..

Overall efficiency would possibly be describing the entire engine/turbo unit as a whole, a turbo diesel is accepted as being more efficient than an NA diesel, therefore should be able to make more power from the same fuel!?

more power with the same consumption? maybe if you compared the diesel pre turbo and post turbo fitment - i.e. if it was overfuelling without the turbo, a turbo could theoretically add more air to burn the wasted fuel and make power.
For example an NA td42, put a turbo on it and you should get a power increase without adjusting the pump, if the pump is untouched full throttle at 3000rpm before or after turbo fitment should use the same fuel, i'd pick the turbo one to have a power advantage.

Patroler wrote:Sounds fair to me...

All flow improvements improve efficiency.

If pumping losses are reduced with the above point - overall efficiency should increase..

While this is undoubtedly true.
It's in no way applicable to installing a "high flow" turbo.

well i bit the bullet and got my self a gt2560r as at 900 bucks brand new it was just to tempting. sightly larger then the farctory turbo with .60ar compressor and .64 ar turbine, . then i shall see how much more of an improvent i get outa the mighty 2.8

I think you will find it will push your boost threshold up a fair bit. - I reckon stock A/R's are in the .4-.5 region.

You will be able to run more boost towards the upper reaches of your rev range so long as the piping can flow the air and you can keep it fueled.

It could be fun, but a higher boost threshold (and a motor that wants to rev more) will normally require lower gears to keep your drivability.

Steve.