Maximum boost and power attainable on an MD321H turbo?
17 September 2007, 07:18 PM
#1
Maximum boost and power attainable on an MD321H turbo?
As per the thread title really. I'm currently running an MD321H on a 2L MY03 STI (UK Spec). Mapped to run just on 1.5 bar in the mid tailing off to around 1.3 at the top end. Runs very well but I'm just wondering what kind of boost I could run on this turbo before it runs out of efficiency if I had forged internals fitted? And what kind of power/torque levels would be achievable at such a level with the right supporting mods?
Cheers
Andrew
Cheers
Andrew
23 September 2007, 08:25 AM
#3
My MD321H (on an 02 STI) currently runs a max of 1.5, dropping to 1.45, and gives me 390bhp. I'm having a boost controller fitted next month (HKS EVC6) which should allow at least 1.6 bar, and if I'm lucky, 1.7 bar. But note that raising the boost mostly raises the torque, not the power - at least that's what I'm told by Paul Blamire. Obviously you will get a slight power increase, but I'm only expecting about another 10bhp. Highest figure I've heard for the H variant is about 420bhp.
M
M
23 September 2007, 10:21 AM
#4
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Although I rate the MD321H at 400bhp, it is capable of quite a bit more on a very well set up engine.
I think the highest I know of so far is about 440bhp on an STi7, mapped by Andy F, with a few more around the 425bhp mark. Up rated internals recommended
The turbo will happily run 2bar, but your mapper will have to see where your specific engine/cam/exhaust, etc', set up is most happy.
Mark.
I think the highest I know of so far is about 440bhp on an STi7, mapped by Andy F, with a few more around the 425bhp mark. Up rated internals recommended
The turbo will happily run 2bar, but your mapper will have to see where your specific engine/cam/exhaust, etc', set up is most happy.
Mark.
23 September 2007, 11:21 AM
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Although I rate the MD321H at 400bhp, it is capable of quite a bit more on a very well set up engine.
I think the highest I know of so far is about 440bhp on an STi7, mapped by Andy F, with a few more around the 425bhp mark. Up rated internals recommended
The turbo will happily run 2bar, but your mapper will have to see where your specific engine/cam/exhaust, etc', set up is most happy.
Mark.
I think the highest I know of so far is about 440bhp on an STi7, mapped by Andy F, with a few more around the 425bhp mark. Up rated internals recommended
The turbo will happily run 2bar, but your mapper will have to see where your specific engine/cam/exhaust, etc', set up is most happy.
Mark.
taken out the calculation or it would have seen more
23 September 2007, 12:04 PM
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Jack,
Thanks, I'd rather under, than over estimate
The other thing I should have mentioned, is the figure was achieved using some methanol. Andy estimated circa 430bhp without.
Mark.
Thanks, I'd rather under, than over estimate
The other thing I should have mentioned, is the figure was achieved using some methanol. Andy estimated circa 430bhp without.
Mark.
Last edited by Lateral Performance; 23 September 2007 at 12:09 PM.
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23 September 2007, 01:30 PM
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Meridian,
Lose the sports cat', turn up the boost, and you should be close, although I'd be interested to know what Paul thinks of the top mount.
Mark.
Lose the sports cat', turn up the boost, and you should be close, although I'd be interested to know what Paul thinks of the top mount.
Mark.
23 September 2007, 03:09 PM
#10
I like the sports cat, so I'll have to lump that. Turning up the boost is what happens next (October). As for the top mount, Paul reckons it's fine. If I can't get what I want any other way then I'll go front mount, but I really want to stay with the TM.
M
23 September 2007, 06:12 PM
#11
Hi CYP - turbo starts spooling around 2800 and is on full chat by 4000rpm. Very progressive spool up makes it feel very 'normally aspirated' on the road - none of this 'on-off' feeling. Very quick to drive. Like Meridian, I'm running a sports cat and I'm wanting to retain my Hyperflow TMIC for throttle response and driveability. I'm currently leaning towards running the 321H on a built 2.35 or 2.5 next year and seeing how I go with that 
23 September 2007, 10:22 PM
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Hi CYP - turbo starts spooling around 2800 and is on full chat by 4000rpm. Very progressive spool up makes it feel very 'normally aspirated' on the road - none of this 'on-off' feeling. Very quick to drive. Like Meridian, I'm running a sports cat and I'm wanting to retain my Hyperflow TMIC for throttle response and driveability. I'm currently leaning towards running the 321H on a built 2.35 or 2.5 next year and seeing how I go with that
I think the H on a 2.35 /2.5 would make a real niceroad car.
JAC
24 September 2007, 01:30 PM
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Interesting that the 3 guys above are getting full boost at approx 4000rpm, I was looking into these turbos a while back and I was going to buy an H but funds didnt allow, im glad I didnt now as 4K is a wee bit late for me
Thus far, I have never seen an MD321T fail to make 450BHP on a 2.5 litre. A "2 litre version", the MD321H, also exists which sacrifices some top end power for spool; on an 2 litre AVCS car it achieved full boost at 3050 RPM and went on to make around 400BHP (limited by injector flow, airflow was still rising). On a non-AVCS car it achieved full boost at 3300 RPM on the road and recorded 407BHP on the dyno, this time "limited" by unknown engine internals.... Again this is on road fuel without any additives. All quoted figures measured on Dyno Dynamics rollers.
For the benefit of others who have not experienced them, I'll try to relate the way they drive to things people are more likely to have encountered... The MD321H "feels" like a VF34, just with more power and torque but the same throttle response. Similarly, the MD321T on a 2.5 litre with AVCS "feels" like a TD04L on a 2 litre (full boost at 2700 RPM), it's virtually lagless. Without AVCS it "feels" closer to a TD05H on a 2 litre, taking a little longer to wind up (full boost around 3200RPM). No data is presently available for MD321T on 2 litre, but one would expect it to achieve full boost around 3700RPM without AVCS.
Cheers,
Pat.
Granted Pat was comparing to a VF34 but my car has a VF35, in 4th gear im on full 1.45 Bar of boost by about 3200 - 3300, 5th its about 2900 and 6th its about 2800rpm so this would eb a big jump in "lag" (im a lazy driver and like my car to pull from no where ) for not too much more benifits as my car is currently running 370 BHP and 364 lbs-ft of torque with fuel additives and in my experience is every bit as fast if not faster that cars with 20G 400bhp applications that I have come accross
Graeme
Thus far, I have never seen an MD321T fail to make 450BHP on a 2.5 litre. A "2 litre version", the MD321H, also exists which sacrifices some top end power for spool; on an 2 litre AVCS car it achieved full boost at 3050 RPM and went on to make around 400BHP (limited by injector flow, airflow was still rising). On a non-AVCS car it achieved full boost at 3300 RPM on the road and recorded 407BHP on the dyno, this time "limited" by unknown engine internals.... Again this is on road fuel without any additives. All quoted figures measured on Dyno Dynamics rollers.
For the benefit of others who have not experienced them, I'll try to relate the way they drive to things people are more likely to have encountered... The MD321H "feels" like a VF34, just with more power and torque but the same throttle response. Similarly, the MD321T on a 2.5 litre with AVCS "feels" like a TD04L on a 2 litre (full boost at 2700 RPM), it's virtually lagless. Without AVCS it "feels" closer to a TD05H on a 2 litre, taking a little longer to wind up (full boost around 3200RPM). No data is presently available for MD321T on 2 litre, but one would expect it to achieve full boost around 3700RPM without AVCS.
Cheers,
Pat.
Granted Pat was comparing to a VF34 but my car has a VF35, in 4th gear im on full 1.45 Bar of boost by about 3200 - 3300, 5th its about 2900 and 6th its about 2800rpm so this would eb a big jump in "lag" (im a lazy driver and like my car to pull from no where ) for not too much more benifits as my car is currently running 370 BHP and 364 lbs-ft of torque with fuel additives and in my experience is every bit as fast if not faster that cars with 20G 400bhp applications that I have come accross
Graeme
Last edited by G.Mac; 24 September 2007 at 01:41 PM.
24 September 2007, 02:23 PM
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4000rpm is not representative of where the MD321H can spool up.
Dyno graphs are misleading, and will commonly achieve spool up 3-500rpm later than what the same car will achieve on the road, and peak "torque", will always be later than peak "boost", on a dyno.
When Pat quotes spool up RPM in the quote above, (1.45bar @ 3300rpm for a non VVT car, and 3050rpm with VVT heads) he is quoting figures actually achieved on the road.
These are not strange "one off's", but what is commonly seen.
There will always be exceptions, depending on the supporting mod's, and mapping.
Mark.
Dyno graphs are misleading, and will commonly achieve spool up 3-500rpm later than what the same car will achieve on the road, and peak "torque", will always be later than peak "boost", on a dyno.
When Pat quotes spool up RPM in the quote above, (1.45bar @ 3300rpm for a non VVT car, and 3050rpm with VVT heads) he is quoting figures actually achieved on the road.
These are not strange "one off's", but what is commonly seen.
There will always be exceptions, depending on the supporting mod's, and mapping.
Mark.
24 September 2007, 05:18 PM
#19
The second line on my graph is torque, not boost. Obviously they are related, but not directly. Paul has the boost curve printout and I can't remember it. I've got a boost gauge though, results from which suggest that boost starts about 2800 and is full by about 3600 - but I'd need to find a nice road somewhere to check. Take those figures as guesses for the moment.
M
M
24 September 2007, 05:29 PM
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Full boost for the above graph occurs at 3500rpm, as it doesn't follow the torque curve precisely, on the road it's more like 3300rpm, but 1 bar by 3200rpm depending on gear.
The VF35 is a great little turbo for 330hp, but it's very poor for big boost as it's so surge happy. If you want a turbo to spool like the VF35 but may 370-400hp, then you need to get a bigger engine, or buy an EVO 9 GT. In my experience the 321H spools faster than a 20g, very slightly later than a 18g.
As i am sure Lunar Tick will testify, a little more boost brings the car a little more alive, with about 325hp/310ftlb at the wheels.
The VF35 is a great little turbo for 330hp, but it's very poor for big boost as it's so surge happy. If you want a turbo to spool like the VF35 but may 370-400hp, then you need to get a bigger engine, or buy an EVO 9 GT. In my experience the 321H spools faster than a 20g, very slightly later than a 18g.
As i am sure Lunar Tick will testify, a little more boost brings the car a little more alive, with about 325hp/310ftlb at the wheels.
Last edited by ZEN Performance; 24 September 2007 at 06:41 PM.
24 September 2007, 09:31 PM
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I'm pretty sure that on Alan Bell's STi7, with 2.5lt (VVT), MD321T Pat achieved 1.6bar by 2600rpm
Cars will vary, as will the results with different ECU's, and how their boost control works.
Mark.
Cars will vary, as will the results with different ECU's, and how their boost control works.
Mark.
24 September 2007, 09:36 PM
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Anders
24 September 2007, 09:55 PM
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On some 2.0lt cars it is possible to induce surge with an H, but it has been pretty rare.
Because the 2.5lt is capable of consuming a lot more air, I'm not aware of surge being an issue, on any of the MD321's.
Mark.
Because the 2.5lt is capable of consuming a lot more air, I'm not aware of surge being an issue, on any of the MD321's.
Mark.
24 September 2007, 10:39 PM
#27
Mine had boost surge soon after the 321H was fitted. Wasn't there initially, but when the weather warmed up a bit (anyone remember the warm weather in May...
) I started getting fairly bad boost surge - at full boost it was hopping between 1 and 1.5 bar at about 2Hz. Paul changed the restrictor and tweaked a bit and it went away.
M
) I started getting fairly bad boost surge - at full boost it was hopping between 1 and 1.5 bar at about 2Hz. Paul changed the restrictor and tweaked a bit and it went away.M
24 September 2007, 11:54 PM
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I wasnt slagging anyone off, I was very close to buying a MD321H but I was hit with a couple of unexpected bills and therefor couldnt aford it.I was only going on what I have heard about the H, granted looking at my graph and the boys above his seems to be hitting peek torque a little before mine but I would not dismiss the "little VF35" just like that
I think im going to stick with my 35 till I go for a 2.5, Im getting set for another map and expecting to get around the 400ish mark on that one
Again cost is the issue, im only keeping the 35 as I know im going to change my engine in about 1.5 - 2 yrs time (once the car is payed off) and will prob go for the MD321T or the GT30-40
Again cost is the issue, im only keeping the 35 as I know im going to change my engine in about 1.5 - 2 yrs time (once the car is payed off) and will prob go for the MD321T or the GT30-40
Graeme
25 September 2007, 12:40 AM
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Graeme,
I don't think anyone was dismissing the VF35, it's a great turbo, and I would expect it to spool up more quickly than a MD321H, especially running a 10% methanol mix.
Very good figures by the way !
Mark.
I don't think anyone was dismissing the VF35, it's a great turbo, and I would expect it to spool up more quickly than a MD321H, especially running a 10% methanol mix.
Very good figures by the way !
Mark.