MD321T MDX321T Turbo Advice
 

Hi All,
Can someone tell me exactly what the difference is between the MD321T & the MDX321T.
After deciding to upgrade my RCM400 I had a short list of MD321T or H or SC46 or 42.
However my mappers opinion is that only the 42 on my list would be suitable, but he has advised me to consider the MDX321T. Car is 96STI 2L CDB fully forged.
I'm inclined to go with my mappers choice as he's always right about my car, but just after other opinions & info on the MDX.

Ones Billet and ones not I assume.

Hi Richard

MDX321T is billet and will spool quicker on the 2.0L
MD321T is non billet and will spool later than MDX321T

We are run MDX321T on our wagon

Jura

So the only difference is the billet wheel meaning it spools earlier & is less laggy meaning it would be suitable for a 2L. Has anyone tried the MDX & the SC42 for a comparison?

I would say yes Billet MDX321T will be more suitable for 2.0L

This is SC42 on 2.0L STi with AVCS

Attachment 57139

This is MDX321T on 2.0L STi with AVCS

Attachment 57140


Jura

Go for the billet H on a 2.0l. It would be ideal with extra spool. Dont let the figures get to you.

I would go slightly further from what KAS35RSTI has said and state that it can certainly be about the figures, but you really need to look at the area UNDER the curve and not just peak.

Based on those two graphs above I would say that the SC42 one is quite a bit better than the MDX321T in the lowdown area. However the graph below (which is mine on a OEM 2ltr JDM with AVCS) is better than both, using the Billet LM450. It has the spool of the SC42 (mine has pretty amazing torque for a 2ltr) and the top end to match the MDX321T.

All peak figures are around the same, but it just highlights what you REALLY need to look at when comparing graphs.

Attachment 57134

It's amazing what 2.0L engine can produce these days with the latest standard location turbos

Not familiar with the LM 450 will try to do some research on it. Iv been told that the MD 321T can have a billet conversion. Will this make it an MDX321T, & is this worthwhile & cost effective?

LM Turbo is Twinscroll from Lichtfield Imports.

Yes is possible to convert non billet MD321T or V to the MDX321T Billet


Jura

Thanks Jura,
LM is no good for me then. If I can get a used MD any idea what it costs to make it an MDX ?

Hi Richard

Price for conversion is £295 plus VAT,but for actual prices would ask Turbo Dynamics or Lateral Performance

https://www.scoobynet.com/trader-ann...et-turbos.html

Jura

It maybe worth mentioning that the graph of the SC42 is running 20% meth for the 472bhp run. Not sure if Steves figure on the MD is also from running meth?

Yes both running Methanol,Steve run 18% and Ken run 20% IIRC



Jura

This is true. Cheers Jura.

Mine is also using a Sports Cat from RCM. :D

Going by Shauns graph that deffo picks up lovely torque. I assume this is due to the Twinscreen getting the gasses up quicker etc?

Personally for me the older version MD321T over the MDX321T Billet
is like night and day. :norty:

Steve

Sorry Steve,Oh I forgot on the yours RCM Sport CAT,but still think this turbo have potential of 500bhp


Jura

Agree 100% mate.

Looking at adding some new fuel rails and lines and may pop in a run with race fuel too? Not sure.


Steve

Fuel lines Steve,you are running braided lines or not?

Race fuel is expensive and really not sure if its worth the extra outcome,we are never tried put our wagon on the rollers after NOS mapping/tweaking

As Duncan and Neil said with better heads we should break 500bhp,which we are never tried :(

You will see how you get on and good luck :thumb:


Jura

:thumb:

Also guys here are graphs for old MD321T over the newer MDX321 (Billet)

MD321 (T)

Attachment 57135


MDX321 (T - BILLET)

Attachment 57136



Hope this helps.


Steve

About to replace my MD321H with the MDX321T Hoping it'll spool as well!
The 321H is a good turbo so I'm a little nervous as to what I'm going to find.
Superb condition MD321H (21k miles) for sale soon!

JohnD

John, Have you considered a billet conversion on your current turbo?

To be honest, no! I had almost settled on the SC42 but wondered how much more it would give, over what I've already got. I was also told that the billet 321T was now fast spooling enough for the 2 litre with VVT It would also be a bit more 'future proof' should the lure of a 2.1 and multi maps etc become too much for me!

JohnD

Im interested in your md321h how much

John we are run MDX321T on our 2.1L and has been spotless,we are loved this turbo and spool up has been great

MD321H is great turbo too,mainly on WRX or classic



Jura

I need to get a bit of advice on prices etc I should know a bit more after Wed. when the swop and map are being done.

JohnD

Ok thats fine keep me
Posted

I'm a huge fan of both the SC42 and SC46.
Used them aplenty on 2.1 strokers and they always deliver the goods.

:thumb:

Sc46, 2.1 Stroker, Alca Tek, by Engine Tuner, V-power:

Attachment 57137

Is the SC46 more laggy on a 2L without AVCS? My mapper has advised me towards the SC42 but has said the MDX321T would be suitable.