iscooby

Hello,

Is anyone running an MD321H turbo on a 2.5L engine? Is it possible or is the turbo to small for a 2.5L?

Thanks...

RA Dunk

The H will be a good set up for a 2.5, Capable of 400 or so horses with bags full of torque, Im thinking you will like it

iscooby

Just the answer I was looking for! Keeping the TMIC and am looking for something very responsive.

trevsjwood

iTrader: (2)

I'd speak to lateral performance before committing. They recommend the bigger turbo for 2.5. The early spool-up will deffo cost you top end.

bigarf

iTrader: (67)

the 321h would be great for such as scoobyshootout with the tight twisty corners,the power would be staight in.

dunx

iTrader: (3)

It should spool like crazy, but it's a 2 bar capable turbo, so you may need a T to fully work a forged 2.5, IMHO.

dunx

iscooby

Anyone running this set up?

RA Dunk

The 20G is a well recommended turbo for a 2.5, since the H is often compared with it i cant see why it shouldent be a good set up for quick spool, Andy.F recently took his MD321T off of his 2.5 set up for scoobysprint and replaced it with a 20G for the quick spool, says enough really

H for low down spool T for top end basically

Jay_

Funnily enough I've not heard of many people running H's on 2.5's. Seems strange as I reckon it would be a ballistic setup with a topmount, extremely quick spool too.

I ran my old 2.0L on an H for years and couldn't fault it... very good spool, so would be amazing on a 2.5 run around 1.5 bar.

iscooby

This is what I was thinking. I guess not many people run them as they wont make big figures?
Would be great to see a dyno graph!

Jay_

Be interesting to see that yes.... if I had to guess I reckon you would see 400-410bhp and about 430 lb/ft with peak boost at a touch over 3k

trevsjwood

iTrader: (2)

Far too many assumptions being made here and that can = disapointment.
Check with Lateral if your're committed to the MD for advice on the turbo and importantly the spec you will need to run alongside it. Just because it's a good turbo for a 2litre doesn't make it good for 2.5.

dunx

iTrader: (3)

Hence my point about it being a 2 bar turbo, if the 2.5 is forged, and can take 2 bar of boost, then you'll probably need a T anyway...

IMHO

dunx

2pot

iTrader: (3)

Back from the dead.
I always thought this would be a good idea; so I'm going to try it - with a non-billet MD321H, on forged, pinned ej257 and V4 sti heads
According to Lateral, they could retro fit 2 versions of billet wheel. One, the same size - spools the same, but flows more than my non-billet. Or a smaller billet wheel and housing - flows the same, but spools up 200 rpm earlier, than my non-billet.
With 3 years hindsight, since this thread was created, what bar to try? Is current thinking now 1.6 bar on a forged 2.5? Could it be squeezed a bit higher as it's a scb and pinned? It's a daily driver.

toyney83

iTrader: (3)

I ran a 321h on mine. seemed fine, good responsive turbo with cracking spool. Made 380bhp at scoobyclinic on the rolllers at 1.4 bar. Had to stop there though as running standard internals on the bottom end. Turbo made 420 bhp on the 2 ltr bottom end

trevsjwood

iTrader: (2)

My standard H made 425hp/456lbsft @1.45bar on RCM rollers, this on straight V-Power, forged 2.5, WRX heads, TMIC, water/meth injection.
The turbo is well within it's efficiency envelope at this, with peak compressor wheel outlets temps of mid 120c, so should produce good power at 1.45bar on a top mount without the benifit of W/M injection.
On my V-Power +20% meth map it made 434hp but the 650 injectors maxed and car ran lean. The plan now is to fit a FPR and up the fuel pressure on the 20%meth map and see what happens.
Trev

2pot

iTrader: (3)

Thanks, both, for those replies.
I may(?) have been a bit pessimistic with my probable performance figures - which is nice.
Just finished fitting an fmic and fpr to my classic wagon.
I wonder what cc injectors 1.6 bar or above will need? Having seen those figures, I wonder if I need anything more than 1.4 bar, for a road car?
Who am I kidding: what's the max bar on my set-up?

trevsjwood

iTrader: (2)

I would have thought 1.6 bar the limit for the H and 650's are a good match unless you are thinking of running meth. The T with bigger injectors would be the next step.
Trev

Jolly Green Monster

iTrader: (4)

Works really well on 2.5

Danny1984

Ive got the T on my 2.5 forged. Dont find any problems wuth spooling think its with the extra torque from the 2.5 though.

Jolly Green Monster

iTrader: (4)

Totally sgree Danny the T is also very nice on the 2.5.

H just spools earlier but ultimately less power

2pot

iTrader: (3)

Dragging up another 3 year old thread - with time, does your statement below still apply?
Talking of torque and cylinder pressures, what bar would you currently advocate on a daily driver, with pinned and forged scb 2.5, md321h and 11mm ARP's?

Jolly Green Monster (Jan 2009) wrote "the answer is not boost but cylinder pressure.. which is obviously effected by boost but more so turbo size.

obviously a large turbo flows more air than a smaller one for the same boost and therefore you have higher cylinder pressures.. however it appears to be torque that kills the cylinder walls.. and obviously someone running 2bar is going to be doing so on a fairly large turbo and therefore it will spool later and therefore run less torque or similar torque to a medium sized turbo..

Some blocks seem to last longer than others and just seems to be luck of how it came out the cast.. there is little support from the ally block for the thin 1mm thick liner.. and therefore it moves and cracks and at worse actually breaks a chunk off which bounces around introducing itself to various parts of the engine..

On top of that you have head gaskets that do tend to fail possibly due to the cylinders moving..

I have been running 1.6bar with occasional higher boost on an ej257 block with md321t making 455lb+ with no issue for several track and dyno session and close to 40k miles.

Simon"

Jolly Green Monster

iTrader: (4)

Yes but if it is pinned the pretty much go as high as the reset of the spec allows and as high as it is decided during mapping.
More boost doesnt alway make more power and torque.
I hsve redone a few cars running similar spec that were mapped to 2bar boost and I got more power and torque running 1.5bar and obviously everything was at less stress.
Sometimes people at obsessed with boost and concerntrate on that boost figure rather than actually checking it makes more power and torque at it.
Just depends on the whole setup and how its mapped.

Simon

2pot

iTrader: (3)

Thanks Simon
Your knowledge is always very helpful.

Jolly Green Monster

iTrader: (4)

Also if you are running on a suitable after market ecu to allow boost cut and safe mapping to higher boost then it may well make more power and torque at that level.

the H comes alive big time around 1.6bar depending on the setup