The MD series turbo's seem to have been available in two forms.... the MD321H and the MD321T. One basically for the 2.0 and the other more suited to a 2.3 or 2.5. I see there now seems to be two others, namely the MD321M and the MD321T+ . Does anyone know how they differ from the other two turbo's ?

Cheers !

Ricky !

The MD series turbo's seem to have been available in two forms.... the MD321H and the MD321T. One basically for the 2.0 and the other more suited to a 2.3 or 2.5. I see there now seems to be two others, namely the MD321M and the MD321T+ . Does anyone know how they differ from the other two turbo's ?

Cheers !

Ricky !

intresting realy

Anyone know what's the difference ?

The MD321M sits between the H and T, in regards to power output. The T+ is a 470bhp turbo on straight v power but will make 500bhp with a splash of methanol.

Banny

My 2005 Sti has the following :

Gt Spec Gen II headers
Full Milltek decat exhaust
Walbro fuel pump
APS sold air induction
Andy F remap

Obviously my two choices then I guess would be either the MD321H or M as my car is a 2.0, with obviously bigger injectors.

Why would I choose one over the other ? Surely anyone fitting a turbo is ultimately looking for more power so why would anyone now buy the H as the M has slightly more power ? You know what I'm getting at.... pro's and con's.........

Ricky,

The M falls between the H, & the T, and the T+ gives about 20-25bhp more than the T, but the throttle response isn't quite as sharp.


Mark.

Banny,

you looking for another job ;)

Do I get to work from home :lol1: ;)

Banny

Ricky,

The M falls between the H, & the T, and the T+ gives about 20-25bhp more than the T, but the throttle response isn't quite as sharp.


Mark.


Hey Mark,

So whats the difference between T and T+ comp wheel size? You can get 500 out of a T on 2.5 with correct modifications, wonder what the T+ would then do?

Tony,

I rate the power of the MD321 turbos conservatively, and as you say some people have had much better results than my ratings, depending on engine set up, fuel type, and rolling road.

Not certain what the max seen out of a T+ is, but over 500bhp, but that will be with 10% methanol.


Mark.

Big numbers and conservative I like...lol.

Is the spool point much different? With my cams, dont think I can afford to have any more spool lost for fast road driving.

Read in the new Total Impreza a MD555 is in development.

Wolfie.

The MD321T has been tested against the MD555, and the MD321T spools up quicker by several hundred RPM !


Mark.

.

Not certain what the max seen out of a T+ is, but over 500bhp, but that will be with 10% methanol.


Mark.

Alan bells was 500bhp/540lbs mapped on his autronics ecu :)

Hi Mark,

Have these been tested on the same car?
If so, do you have some data which you can share with us?
I expect the MD555 would have more power up top, but at the loss of some spool, but it would be great to know what the respective torque curves look like. :)

Cheers
Richard

The MD555 has some defficiency's when compared to the 321T, for now, having mapped both, I would stick with the 321T, I would also say the T is a better bet than the M for most applications, the H is the daddy when it comes to the std engine at circa 400 bhp. As Mark says he does rate on the mean side.

Bob

__________________________________________________ _________________

Link, Motec, Simtek, EcuTek, PowerFC, DTA, Bosch, Autronic, Gems, ESL

So what would be the best buy for my 2.0 then ? The H, M or T ????

Could I buy the T and use a lower boost map, cause if anything ever did go wrong I'd be buying a 2.5 bottom end anyway. Would I get the same results using the T that way as I would using the H or M with higher boost bla bla bla ......

My spec is :

Gt Spec Gen II headers
Full Milltek decat exhaust
Walbro fuel pump
APS sold air induction
Remap

So what would be the best buy for my 2.0 with standard internals then ? The H, M or T ????

Could I buy the T and use a lower boost map, cause if anything ever did go wrong I'd be buying a 2.5 bottom end anyway. Would I get the same results using the T that way as I would using the H or M with higher boost bla bla bla ......

My spec is :

Gt Spec Gen II headers
Full Milltek decat exhaust
Walbro fuel pump
APS cold air induction
Remap

I ran a 321H on my 2.0 JDM STI for over a year and it was fantastic. Very good spool on the 2.0 considering it was over 400bhp:)

Am now running an MD555 on a 2.35 and have just recently ironed out some minor glitches, yet to be re-tweaked by Bob.... it's stunning now:thumb: Will be interesting to see how it really does compare to the T once finished off. Sorry, but no dyno runs or figs as yet.

I would probably avoid T on a 2.0 litre as it will be a bit too laggy. Best bet is the H I reckon.

The MD555 has some defficiency's when compared to the 321T, for now, having mapped both, I would stick with the 321T, I would also say the T is a better bet than the M for most applications, the H is the daddy when it comes to the std engine at circa 400 bhp. As Mark says he does rate on the mean side.

Bob

__________________________________________________ _________________

Link, Motec, Simtek, EcuTek, PowerFC, DTA, Bosch, Autronic, Gems, ESL


Interesting comment Bob , in what way was it lacking ?

MD555 is a fantastic turbo, does what it says on the tin.

I ran a 321H on my 2.0 JDM STI for over a year and it was fantastic. Very good spool on the 2.0 considering it was over 400bhp:)

Am now running an MD555 on a 2.35 and have just recently ironed out some minor glitches, yet to be re-tweaked by Bob.... it's stunning now:thumb: Will be interesting to see how it really does compare to the T once finished off. Sorry, but no dyno runs or figs as yet.

I would probably avoid T on a 2.0 litre as it will be a bit too laggy. Best bet is the H I reckon.

I have a T on my 2.0, at first I wasnt sure, but I have driven the car more recently and got used to it. Love it now and it is very rapid indeed. :norty:

MD555 is a fantastic turbo, does what it says on the tin.

Have you got one on your car ?


Mark.

I have the 321H Still running with a 2.5" system and its still really good to drive, I will be going up to a 3" soon , look forward to see what difference it makes. On the 2.0 std internal sti the H is a great turbo.

I still have the 2.5 inch system on mine, will it make a huge difference with a 3.0 inch, with map tweak of course.

Yes Andy F Will be giving it a nice map tweek too :)
lets see what the difference will be.

Have you got one on your car ?


Mark.

No Mark , he doesn't ...He has the earlier MD195s which is working very well producing 464bhp and 400lbft @ 1.5 bar at the Powerstation rolling road day also featured in Total Impreza..
The new one is based on the info gathered over the last 8 years of producing the 195s and the 321 range as stated in the mag feature...

In answer to the original question posed I guess it is all a matter of personal taste and the use you put it to...
For a really good road car instant torque has always been my favourite so I believe the H would be the correct one for that application...
If you can cope with a small increase in lag for an increase in power then the T is probably for you....
Either way choose the smallest turbo to match your intended power goal ...


Martyn

Alan bells was 500bhp/540lbs mapped on his autronics ecu


Mapped by Paul Zen on 100 octane pump fuel. It now produces 390bhp/395lbs at the wheels. Probably about 470 - 480bhp and similar torque. Seems to have lost more torque rather than bhp now that it is not on methanol. Not that you can tell:) All this at 1.7 bar and a 7000rpm limit (and 35 degree heat). It is frightening the way it picks up speed. Makes my hillclimb car with a 2.2 and GT35 seems sluggish and unresponsive.

Excellent spooling turbo and engine combo. Would recommend the T+ on a 2.5. Think this engine may go nicely in my hillclimb car.

. Makes my hillclimb car with a 2.2 and GT35 seems sluggish and unresponsive.

.


But the gt35 is a superb 600bhp turbo where as the md321+ is only a 500bhp turbo :) I have the gt35 on mine mapped low and its an excellent turbo :)

Yes you are right, although the GT35 comes on like a rocket at 3700rpm and does cause some hairy moments on a hillclimb, whereas the MD with the 2.5 is just one long push with no step in power.