RB25 td06-20rx vs 25g

[Prof_Finesser]

I have a built bottom end semi built head trying to decide between these two and don’t really see any info on the 20rx I’ve seen some videos on them but not really much info.  I want to be in the low 400whp range and be responsive I’ve been looking at some dyno sheets for the 25g but I do want the 8cm rear for response and I can’t find any it’s all 10cm.  I wanted to see if anyone has some info about the 20rx and could get me to my goals also if anyone has sheets or know if I could run a 25g 8cm and be in the low 400s if not how bad is the lag for 10cm.  Ik there’s better turbos for the same price but I’m in it for the sound and td06s are a classic.
 

 

hks 264 no vct (de block and head)

8.5:1

greddy mani

[Lithium]

Are the Trust TD06-20RXs super super cheap?  I'm not sure why you'd go a TD06 these days unless it costs almost nothing.

From the perspective of someone who has been into RBs/turbos for over 2 decades now - I remember a time where TD06 20Gs were a wicked thing for an RB20/25.  Like they cost less, were strong, and performed admirably (for a journal bearing turbo) against Garrett/HKS turbos which cost a lot more back in the day - a 20G would be a solid alternative to something like a Garrett GT3071R or HKS 2835 for sake of argument.    That was around 20 years ago.

In that time Garrett have since released a GTX3071R, then Gen2 GTX3071R, then the G25/G30 range of turbos - and there are budget equivalents semi-loosely based off all the previous things.   This TD06 20RX from everything I can see is basically Trust finally upgrading the compressor wheel (but nothing else) to something comparable flow wise to the improvement Garrett did with the GTX3071R, a turbo that's been available for about 13 years now.    If the year was 2010 and this turbo had just came out THEN (and at a sharp price point) then I'd understand threads like this coming up... but in 2023 I just don't have a clue why they'd be a thing anyone would consider.

So yeah, short answer - it's something that will spool like a TD06 20G (a 400whp turbo from 1998) but is capable of around 10% more power.  But a Pulsar GTX3071R (or the like) will probably cost less and do everything better.  

 

[Prof_Finesser]

24 minutes ago, Lithium said:

Are the Trust TD06-20RXs super super cheap?  I'm not sure why you'd go a TD06 these days unless it costs almost nothing.

From the perspective of someone who has been into RBs/turbos for over 2 decades now - I remember a time where TD06 20Gs were a wicked thing for an RB20/25.  Like they cost less, were strong, and performed admirably (for a journal bearing turbo) against Garrett/HKS turbos which cost a lot more back in the day - a 20G would be a solid alternative to something like a Garrett GT3071R or HKS 2835 for sake of argument.    That was around 20 years ago.

In that time Garrett have since released a GTX3071R, then Gen2 GTX3071R, then the G25/G30 range of turbos - and there are budget equivalents semi-loosely based off all the previous things.   This TD06 20RX from everything I can see is basically Trust finally upgrading the compressor wheel (but nothing else) to something comparable flow wise to the improvement Garrett did with the GTX3071R, a turbo that's been available for about 13 years now.    If the year was 2010 and this turbo had just came out THEN (and at a sharp price point) then I'd understand threads like this coming up... but in 2023 I just don't have a clue why they'd be a thing anyone would consider.

So yeah, short answer - it's something that will spool like a TD06 20G (a 400whp turbo from 1998) but is capable of around 10% more power.  But a Pulsar GTX3071R (or the like) will probably cost less and do everything better.  

 

I know there’s a so many turbos that are better but I do like how the old td06s are and how they sound mainly and I’m really going towards the 25g many ppl still use them in Japan and love them 

[Lithium]

8 minutes ago, Prof_Finesser said:

I know there’s a so many turbos that are better but I do like how the old td06s are and how they sound mainly and I’m really going towards the 25g many ppl still use them in Japan and love them 

Ok, should have said that was your priority instead of response - a preference because you just like the idea etc is fine.

So the TD06-20RX will basically make the power of a 25G but with the spool of a 20G.  Turbine is the same so should have the same "Mitsi turbo" exhaust note you're probably looking for.  

[CefiroA31]

I assume you have non vct rb25de with greddy 3 bolt turbo flange manifold, if it must be trust turbo, get trust td06sl2-20rx. As tested by trust on td06sh, 20rx spools like 20g but peak hp close to 25g, so higher average hp than 20g or 25g. By trust pictures, 20rx compressor looks like similar size as 20g compressor with smaller center hub, taller + extended tip blade, so its good as it has 20g spool but close to peak hp of much larger 25g (20g 52.6mm/68mm compressor, 25g 60.5mm/78mm compressor). What doesn't show on dyno plot is spool up/response time and lag, 25g being larger will has more inertia thus lazier than 20g and 20rx, and 20rx nearly match 25g peak hp so I see no pros of 25g vs 20rx. 

Turbine side I suggest to go with smaller td06sl2 54.1mm/61mm it should be enough to support 20rx compressor if using 10cm turbine housing (my experience with holset twin scroll 10cm spools quick and not choking on rb20, so single scroll 10 cm which flow more than twin scroll 10cm should match well with rb25, while single scroll 8cm better match rb20 but may choke on rb25). Td06sh is just regular mhi td06h turbine, its bigger at 58.8mm/67mm, also has more inertia thus lazier than td06sl2. Due to bigger wheel has more inertia thus lazier spool, for similar max flow I prefer smaller wheel + bigger housing (td06sl2 10cm) vs bigger wheel + smaller housing (td06sh 8cm).

[Prof_Finesser]

10 hours ago, CefiroA31 said:

I assume you have non vct rb25de with greddy 3 bolt turbo flange manifold, if it must be trust turbo, get trust td06sl2-20rx. As tested by trust on td06sh, 20rx spools like 20g but peak hp close to 25g, so higher average hp than 20g or 25g. By trust pictures, 20rx compressor looks like similar size as 20g compressor with smaller center hub, taller + extended tip blade, so its good as it has 20g spool but close to peak hp of much larger 25g (20g 52.6mm/68mm compressor, 25g 60.5mm/78mm compressor). What doesn't show on dyno plot is spool up/response time and lag, 25g being larger will has more inertia thus lazier than 20g and 20rx, and 20rx nearly match 25g peak hp so I see no pros of 25g vs 20rx. 

Turbine side I suggest to go with smaller td06sl2 54.1mm/61mm it should be enough to support 20rx compressor if using 10cm turbine housing (my experience with holset twin scroll 10cm spools quick and not choking on rb20, so single scroll 10 cm which flow more than twin scroll 10cm should match well with rb25, while single scroll 8cm better match rb20 but may choke on rb25). Td06sh is just regular mhi td06h turbine, its bigger at 58.8mm/67mm, also has more inertia thus lazier than td06sl2. Due to bigger wheel has more inertia thus lazier spool, for similar max flow I prefer smaller wheel + bigger housing (td06sl2 10cm) vs bigger wheel + smaller housing (td06sh 8cm).

Thanks for that but I’ve heard that there’s not really a difference on dyno with L2 I seen one where two identical rb20s and the graphs were basically the same as they were running the same psi and same turner 

Edited October 11, 2023 by Prof_Finesser

[WMDC35]

On 10/11/2023 at 3:08 PM, Lithium said:

Ok, should have said that was your priority instead of response - a preference because you just like the idea etc is fine.

So the TD06-20RX will basically make the power of a 25G but with the spool of a 20G.  Turbine is the same so should have the same "Mitsi turbo" exhaust note you're probably looking for.  

Back in the times when they were popular it was usually td06l2/sl2 20g, td06h/sh 20g wasn't something you seemed to see around?

[WMDC35]

On 10/12/2023 at 3:02 AM, Prof_Finesser said:

Thanks for that but I’ve heard that there’s not really a difference on dyno with L2 I seen one where two identical rb20s and the graphs were basically the same as they were running the same psi and same turner 

T67 25g 10cm would usually make 20 psi before 4k on a 25 although with a bit more compression and vct than you're running, td06h/sh 25g was usually around 300rpm later, t67 with 8cm was only marginally more responsive but down around 30kw up top.

Be surprising for the l2 to not be more responsive than sh especially on a rb20, although old news I'm wondering why the sh with the 20 comp haha, maybe the sh worked better with 8cm than l2 with 10cm.

[Lithium]

On 11/10/2023 at 4:49 PM, CefiroA31 said:

my experience with holset twin scroll 10cm spools quick and not choking on rb20

A Holset HX35 and a Mitsi TD06(/SL2) are *completely* different turbines - you absolutely cannot take what a Holset 10cm divided housing behaves like and try and use that to determine what a turbo with totally different housing and wheel geometry on both sides will do.   May as well say they're both loosely based on circles so will behave similar.

2 hours ago, WMDC35 said:

Back in the times when they were popular it was usually td06l2/sl2 20g, td06h/sh 20g wasn't something you seemed to see around?

Hmmmm.   I did write a post saying that the only ones I experienced were the bigger ones but decided to verify and there is every possibility I had actually been exposed to TD06SL2 20Gs when they had been referred to as simply "TD06 20G" so I'm actually going to have to not weigh in on that. 

The only thing I *can* add to the "maybe the SL2 doesn't add as much value as it's given credit for" is arguably the most famous TD06 aside from the TD06(something)-20G is the classic FP Green which was basically a 50-trim T4 compressor paired with a TD06H turbine, and had the reputation of outspooling and out flowing 20Gs of almost any combination... though this potentially brings the whole "compressor vs turbine matching magic" side of things into the discussion.   Sometimes the result can't exceed or fall short of the sum of the parts.

My memory also probably stretched here, but one of the best 20G setups in the entire RB kingdom was @Roy's RB20... I'm not sure that was an Sl2? 

Edited October 13, 2023 by Lithium

[discopotato03]

Short of time at the moment but .

Recently I noticed that Mitsubishi released a turbine called (from memory) TF06 - which is sort of similar dimensions to a GT30 turbine . The turbo is called TF06-18K and similar wheel wise to a GT3076R .

They have the most modern Mitsy wheel designs AFAIK .

 

[Lithium]

2 hours ago, discopotato03 said:

Short of time at the moment but .

Recently I noticed that Mitsubishi released a turbine called (from memory) TF06 - which is sort of similar dimensions to a GT30 turbine . The turbo is called TF06-18K and similar wheel wise to a GT3076R .

They have the most modern Mitsy wheel designs AFAIK .

 

They've been out for a few years and actually a "joint" effort with (or FP say basically is a FP turbo that Mitsi liked so much they've sold as an OEM option) Forced Performance.   They seem like excellent performers and are loosely FP Greenish from memory.  

They also happen to be "standard rotation" as they are an Evo X option

Edited October 17, 2023 by Lithium

[hypergear]

Here's something I've done 10 years ago. Making custom comp wheeled TD06SL2-20G. Not sure if that became the 20rs equivalent 😂

R33 GTST, Rb25det with forged pistons and valve springs. Turbo was in 10CM rear, Externally gated run on E85 fuel. 

[WMDC35]

19 hours ago, hypergear said:

Here's something I've done 10 years ago. Making custom comp wheeled TD06SL2-20G. Not sure if that became the 20rs equivalent 😂

 

Probably not, the 20RX above has the H/SH turbine haha.

[Prof_Finesser]

On 10/17/2023 at 8:27 PM, hypergear said:

Here's something I've done 10 years ago. Making custom comp wheeled TD06SL2-20G. Not sure if that became the 20rs equivalent 😂

R33 GTST, Rb25det with forged pistons and valve springs. Turbo was in 10CM rear, Externally gated run on E85 fuel. 

Ok thx for the info I think I’m going to go with the regular rear turbine on the 20rx with a 10cm housing and if i don’t like the response I might go to a 8cm I would like to run the 25g just cuz it says powered by trust on it but too much lag lol

Edited October 24, 2023 by Prof_Finesser

[Prof_Finesser]

The 20rx is on the way hopefully post some dyno sheets soon hoping to get on the dyno in December or January engine is still at machine shop