Holset HX55 on a LDT 465-1D?

[Bantha RV]

Greetings guys. I tried quite a few search terms looking to find out if and HX55 or HX52 would be a good swap for the D turbo. If this has been addressed somewhere else I’ll gladly follow a link and stop wasting everyone’s time with a fresh thread….I just can’t find it after searching and scrolling through 25 pages in this forum.

My truck is currently a stock AMG 1971 M109A3 with Continental LDT 465-1D with the exceptions of:
- FDC bypassed
- EGT and Boost gauges installed
- 395/85 R 20 on MRAP wheels

I currently get about 11# of boost max and EGT comfortably stays below 1200* even under load. It does 55mph indicated (63mph actual) on the level with about 6# of boost and 800* EGT. So it seems like my fuel is set at a pretty good spot with the current turbo.

I’ve seen and read about guys putting in HX40 with good results. I’d like to minimize leak and drag points, and both the HX55 and HX52 can be had with a T6 flange which avoids the need for an adapter to a T4 like on the HX40. However, it seems the smallest turbine (hot end) is 22cm with that flange size, whereas the HX40s are 16cm. The HX52 and HX55 are rated for displacements from 7L and up, so our little 7.8L straight sixes are at the small end of their applicability.

The torque curve on the multi-fuel has all the power at the bottom end and I’m mostly interested in trying to even that out by getting more boost at the top end to improve highway and hill performance. I don’t need the turbo to spool up super fast, but I’d like to have the truck still make decent power at 2200-2400rpm or so. I also want to keep EGT down so would rather error on the side of a little lag from a bigger turbine rather than a restriction from too small of one.

On the cool side both the HX52 and HX55 have pretty big compressors with 65mm-67mm inducers vs the 60mm on the HX40. Both can be found with internal waste-gates as well.

Not needing to go any faster, not needing to accelerate any harder, but want to be able to pull a hill a little better without being a portable chicane and getting rear ended by someone on their cellphone.

Just wondering if anyone has real world knowledge playing with these bigger turbos on the multi-fuel, or if I’d be better off sticking with the HX40 and a T6 to T4 adapter.

Thanks in advance for any insights.

 

[cattlerepairman]

First off, I have no clue. But I find adapting more modern parts to a 50 year old engine fascinating.
I hope somebody has some insights!

Sent from my SM-G991W using Tapatalk

 

[USN_Green_Addict]

Greetings guys. I tried quite a few search terms looking to find out if and HX55 or HX52 would be a good swap for the D turbo. If this has been addressed somewhere else I’ll gladly follow a link and stop wasting everyone’s time with a fresh thread….I just can’t find it after searching and scrolling through 25 pages in this forum.

My truck is currently a stock AMG 1971 M109A3 with Continental LDT 465-1D with the exceptions of:
- FDC bypassed
- EGT and Boost gauges installed
- 395/85 R 20 on MRAP wheels

I currently get about 11# of boost max and EGT comfortably stays below 1200* even under load. It does 55mph indicated (63mph actual) on the level with about 6# of boost and 800* EGT. So it seems like my fuel is set at a pretty good spot with the current turbo.

I’ve seen and read about guys putting in HX40 with good results. I’d like to minimize leak and drag points, and both the HX55 and HX52 can be had with a T6 flange which avoids the need for an adapter to a T4 like on the HX40. However, it seems the smallest turbine (hot end) is 22cm with that flange size, whereas the HX40s are 16cm. The HX52 and HX55 are rated for displacements from 7L and up, so our little 7.8L straight sixes are at the small end of their applicability.

The torque curve on the multi-fuel has all the power at the bottom end and I’m mostly interested in trying to even that out by getting more boost at the top end to improve highway and hill performance. I don’t need the turbo to spool up super fast, but I’d like to have the truck still make decent power at 2200-2400rpm or so. I also want to keep EGT down so would rather error on the side of a little lag from a bigger turbine rather than a restriction from too small of one.

On the cool side both the HX52 and HX55 have pretty big compressors with 65mm-67mm inducers vs the 60mm on the HX40. Both can be found with internal waste-gates as well.

Not needing to go any faster, not needing to accelerate any harder, but want to be able to pull a hill a little better without being a portable chicane and getting rear ended by someone on their cellphone.

Just wondering if anyone has real world knowledge playing with these bigger turbos on the multi-fuel, or if I’d be better off sticking with the HX40 and a T6 to T4 adapter.

Thanks in advance for any insights.

I am by no means an expert on turbos, from my reading the data points needed are different volumes & pressure needed to create boost at lower RPM, adjustable wastewater so you don't blow it, and flow to help EGTs. Are you going to need to fabricate a inlet due to size and distance? What size outlet adapter are you looking at for the exhaust and are you looking at doing a full exhaust?

 

[Bantha RV]

I am by no means an expert on turbos, from my reading the data points needed are different volumes & pressure needed to create boost at lower RPM, adjustable wastewater so you don't blow it, and flow to help EGTs. Are you going to need to fabricate a inlet due to size and distance? What size outlet adapter are you looking at for the exhaust and are you looking at doing a full exhaust?

I’m expecting to need to tweak the turbo inlet, but that is easy. The turbo to intake manifold will not need any fabrication and the exhaust is a V-band outlet, so easy to adapt to the current J pipe.
I have my eye on an adjustable wastegate that will bolt right on to a HX52W and then use the existing internal wg.

I found an HX52W that has a T4 flange and 16cm turbine, with a 67mm compressor inducer. I think this will be my best option and I’ll just need to go with the T6-T4 adapter. 16cm should be good for a 7.8L engine and the bigger compressor should move the torque up the power curve.

I also found an HX50 (also T4) with a 19cm turbine (kind of splits the difference between the 16cm and 22cm) that still uses the 67mm compressor inducer. No wastegate on that unit but I might give it a try just to see the difference in lag/EGT between the two.

I think the 22cm minimum for the T6 flange is too big of a wheel for our little motors.

Any thoughts from the brain trust?