Thread: Will this turbo suit the 4BD1 ??

The turbo on one of our 200tdi d1s is an Airesearch, looks abit like that
I think airesearch is another name for the brand garret, could be wrong

TIM.

I thought they were Garrett by another name. The turbo should be a T3 and has an ok exhaust AR for a 4BD1T. The turbo engineer that fitted my setup was wanting to fit this turbo or something similar with a small exhaust AR. 0.63 AR is about as small as available in T3 when I was looking. I am pretty sure Bearman has this turbo fitted to his 110.


The following explanation of A/R is from Garrett:

A/R describes a geometric characteristic of all compressor and turbine housings. It is defined as the inlet cross-sectional area divided by the radius from the turbo centerline to the centroid of that area.

• Compressor A/R - Compressor performance is largely insensitive to changes in A/R, but generally larger A/R housings are used to optimize the performance for low boost applications, and smaller housings are used for high boost applications. Usually there are not A/R options available for compressor housings.
• Turbine A/R - Turbine performance is greatly affected by changing the A/R of the housing. Turbine A/R is used to adjust the flow capacity of the turbine. Using a smaller A/R will increase the exhaust gas velocity into the turbine wheel, causing the wheel to spin faster at lower engine RPMs giving a quicker boost rise. This will also tend to increase exhaust backpressure and reduce the max power at high RPM. Conversely, using a larger A/R will lower exhaust gas velocity, and delay boost rise, but the lower backpressure will give better high RPM power. When deciding between A/R options, be realistic with the intended vehicle use and use the A/R to bias the performance toward the desired powerband.

AiResearch was Garrett's turbocharger division before it got renamed to Garrett Automotive. Garrett also makes gas turbines, so all Garrett turbochargers were branded AiResearch until the division was renamed sometime in the late 90s(?), I think.

86 x 44.5 is a T3 Flange, so will be a direct bolt on for these manifolds. That one comes with all gaskets and new ehnaust bolts, which is a bonus, and shipping to Perth was ~$65 US from memory.

Bojan

As it doesn't have an internal wastegate, you may like to leave some wiggle room in case an external one is needed.

The stock garretts on 4BD1-T's are free float (no wastegate) but there may be differences to yours that may require a wastegate. If you have some time, just try it without first.

Wastegates don't just limit boost pressure, they also reduce drive pressure - excessive drive pressure reduces power. Drive pressure is the pressure in the exhaust manifold (that is driving the turbine).

You can increase boost pressure without gaining performance if the drive pressure increases proportionaly higher. Conversely power can be increased with lower boost pressure, by reducing drive pressure.

If you fit a pressure tapping in the exhaust manifold and measure both drive and boost pressure, it will become apparent (high drive pressure relative to boost pressure) whether you need a wastegate or not.

Originally Posted by Bush65

As it doesn't have an internal wastegate, you may like to leave some wiggle room in case an external one is needed.

The stock garretts on 4BD1-T's are free float (no wastegate) but there may be differences to yours that may require a wastegate. If you have some time, just try it without first.

It does have a small connection on the compressor housing which suggests it might have had an external wastegate, or maybe just a boost gauge.
I will just try it without a wastegate first. When I was mucking around with my County I found the engine would only push the turbo to a certain point anyway, before turning up the fueling.

Murray

Originally Posted by rijidij

It does have a small connection on the compressor housing which suggests it might have had an external wastegate, or maybe just a boost gauge.
I will just try it without a wastegate first. When I was mucking around with my County I found the engine would only push the turbo to a certain point anyway, before turning up the fueling.

Murray

That hole is too small for an external wastegate.

As the others have spotted, it's a garrett T3 with a 0.63 A/r exhaust housing and no wastegate.
Yes it's a good match for the 4BD1T, but it'll depend on your state of tune as to whether you need a wastegate or not.
Basically a more detuned diesel has less exhaust heat so less exhaust volume and won't choke itself or overspeed the turbo.

If you want to add a wastegate, then a wastegated turbine housing should be available. You'll need to know the exhaust wheel size to order one but any half decent turbo shop will be able to look up and sell you an appropriate housing. Wastegated housings are available in a smaller range, down to abotu 0.48 A/R I beleive.

You could fit an overboost protection valve on the compressed air side just before the intake. That's how mine is set up. I don't think my waste gate moves. I have heard the overboost valve.