dazdavies

iTrader: (22)

Mine is all ready to try one of these turbos on.

Fully built 2.0L

Just made 358bhp 322 ft lbs on a dyno today with a VF28

The sceptical can see todays post in my projects thread for more details as to the current specs etc here https://www.scoobynet.com/projects-4...c-2-0l-15.html

Please read the last posts in that thread before shooting me down

However I think an MD321T would be perfect for mine.

Guinea pig anyone???

ZEN Performance

I wouldn't get too excited until you get it back onto (for instance) scoobyclinic's rollers. Good figure nonetheless.

Does it feel like it has 30hp more than it used to?

dazdavies

iTrader: (22)

Dont know if you have read the post I made today in my projects thread however, I shall eloborate here.

The Run on Scooby clinic dyno was done before my documented rebuild started. However that day it made 330bhp and 298ft lbs

The spec then without going into too much detail was:
STI 5 V engine with STI 9 crank eagle rods standard STI Forged pistons,
walbro fuel pump with standard fuel rails and standard reg with 440cc Injectors.
NGK6's
Running standard UK top mount IC and an ECUTEK'd ecu mapped by Andy.
TSL group A down pipe, TSL Decat centre section, and TSL firestorm backbox
2.5in all the way through

Todays run was done with the same turbo but with the following additions:
rebuilt engine with wiseco forged pistons (93mm with a comp ratio of 8.35:1)
Same crank and rods
Apexi Power FC ECU mapped by Andrew carr
740cc Injectors (peaked at 76% duty)
Parallel fuel rails with braided hoses and all the goodridge elbows and T's
SX FRP set at 3 bar atmosheric
Front Mount Intercooler
NGK 7's
Buddy Club 3in Exhaust system

Also According to Andrew he was quite conservative with the mapping due to the misfire at the time he said he took a fair bit of advance out .
How much more power, if any, additional mapping would produce I dont know.

However I would say that the car is notibly quicker than its previous guise.

If you look at the additional mods I dont think an extra 28bhp is unrealistic. Do you??

Would be interesting to see people's opinions on this. I also think mine would be the perfect car to ascertain just what the MD321T does on a 2.0L that appears to be giving good results on the standard STI 5/6 Turbo.

Daz

pat

I cannot see any relevant information ? WRXshaneWRX asked for a turbo capable of 450BHP. A suggestion was made that an MD321T would be suitable. You then said "I very much doubt that an MD321 T will be capable of 450 bhp on a 2 litre", but presented no information on which to base that assertion. You then went on to say that your experience of an MD321L suggested that the MD321T would struggle to make 450BHP, but you don't say that you've actually tried it and failed, so I can only conclude that you haven't tried. The fact that the car equipped with the MD321L you do have experience of is having difficulties does not, in any way, validate the argument that the MD321T would exhibit the same problems.

In trying to back up your assertion, you are blaming the MD321L for the poor performance of a 2 litre motor, but you fail to explain exactly how you came to the conclusion that it must be the turbo, and that it cannot possibly be anything else. Do you have the relevant data to support that conclusion ?

I'm a techie so I like to know the specs of what I'm dealing with, but most people don't want to know, or care about things like turbine size, trim, compressor cover A/R etc etc, all they care about is how much power a turbo will make and how it drives. It is pointless giving unnecessary details and confusing the hell out of someone when a simple statement such as "An MD321L will spool a bit slower and produce a bit more power than an MD321T" conveys all the information needed to understand how the two differ. Because that statement doesn't quantify how they differ, it would be wrong to infer from it that they are sufficiently similar to consider them comparable to the point of extrapolating results from one to predict results from the other. As with anything in life, there is more than one way to achieve a particular goal, some ways may prove more successful than others... there are several cores in the Garrett GT series that are capable of hitting the target power, the MD321T uses one core, the MD321L uses a different core with a slightly higher flow potential sacrificing spool for top end power.

Cheers,

Pat.

Andy.F

Daz

I'd have to agree with Paul, only compare the results on the same dyno, preferably even the same operator who has no vested interest in the results. Torque should be up by approx 25% (75lbft) at the same boost, power should also be up due to the FMIC providing a cooler charge, particularly on the rolling road.
I've just had a report of my TD04 hybrid having made 337bhp today somewhere in the South, I have not seen this level of bhp further north.

Andy

harvey

iTrader: (48)

Pat : This is what the purchaser of the turbo said :
As far as he was concerned the two turbos were very similar in construction or he had been led to believe that. It is now clear they are completely different.

Mark : What 321Ls are producing 450 bhp on 2 litre cars ?
Why not publish the compressor maps and we can see clearly what a 321L and T are capable of and avoid the need for all these posts.
I stated clearly I was talking about a 321L and the purchaser of the turbo was led to believe it was very similar to a 321T but with slower spool but similar power output. It was you who gave these impressions.
BTW. Full boost at 5000 rpm is very slow spool.

Possible restrictions were detailed to the car owner and the original purchaser of the turbo but even on removing these restrictions will not lift power from 390 to over 450 bhp.

To clarify. If the turbo was maxed out on a 2 litre and then fitted to a 2.5 litre and it could be maxed out in each case because the turbo was not restricted by other factors then the bhp would be similar in both cases but the torque would be lower on the 2 litre but higher up the rev range.
Publish the compressor graphs and we can see what the turbo is capable of.

I have exactly the vehicle you need for this test and can fit and remove your turbo at no cost to yourself and probably get dyno time thrown in too. The car as you know is currently 420.7 bhp at just a little over 6000 revs on one of my own TD05-06 20Gs with Sigma ECU and the figures were obtained on Optimax plus 2mls per litre NF. BTW I am looking for a bigger turbo anyway.

pat

Neilo (and others that are interested ....

The 2.5 litre Subaru engine is less efficient than the 2 litre for several reasons. I'll try to outline the differences below...

a) Combustion dynamics

The 2.5 litre engine has a larger bore. That means the flamefront has further to travel. At equal flamefront speeds it will therefore take longer to fully burn the charge than on a 2 litre, ergo you need to run more advance in order to place peak cylinder pressure near 16 degrees ATDC to achieve peak thermal efficiency. Given that we know that it takes longer for the flame to propagate, the amount of heat put into the area directly in front of the flamefront at the extremities of the bore will be greater and therefore the propensity for the fuel to autoignite will also be greater.... ie it will have less timing tolerance but greater timing requirement. This is not an insurmountable problem and clever engineering of the combustion space can yield some useful gains.

b) Pumping losses

Air doesn't magically want to go into the cylinder, it has to be persuaded in there. Given the same aperture for the air to go through, it will take more effort to move a larger amount of air in the same period of time. Additionally, the larger bore also means that the friction from piston rings will be higher. Once you've burnt all your charge it doesn't magically just all flow out the exhaust; some is propelled out by the residual cylinder pressure at the point the exhaust valve opens (known as a "blowdown"), but the rest has to be pushed out. Again, there is more to push out so it takes more effort

c) Thermal efficiency

There is a larger surface area exposed to the flame in a 2.5 litre than a 2.0 litre. It therefore stands to reason that more heat will be lost into the head, cylinder walls, piston crown. The cylinder wall is perhaps a little less important because at the point where you really, really don't want to be losing heat to the surroundings very little of the cylinder wall is exposed... ergo increasing stroke has a smaller effect on heat loss than does increasing bore. The stroke on the 2.5 is 5.3% longer, while the bore area is 17% bigger, so it's not looking too good there. In order to extract the maximum amount of useful energy from the working fluid, you have to achieve peak pressure at a certain crank angle, typically around 16 degrees ATDC. As we have already seen, the combustion space and dynamics make this more difficult, but there's more :

d) Working fluid flow

Air has to get into the cylinder, mixed with fuel, in order for it to be lit at the right point in time, heat up and then allowed to do work against the piston during expansion, and then it is exhausted once the useful energy has been extracted. That's where it gets a bit ugly. When the piston reaches TDC there is a clearance volume, a remaining space that the piston cannot "squeeze out" due to the chamber in the head and the dish in the piston crown. It is important to get reid of any burnt gasses left in these spaces so they don't contaminate (and much more importantly, HEAT) the new fresh charge coming in. We already know that we have to push more working fluid through the same orifice which increases pumping losses, but if we have to exhaust more and we also have a large remaining volume at TDC (if we maintain the same mechanical compression ratio) then it makes it much harder to flush out the remaining gasses. Camshafts play an important role, with overlap (where both inlet and exhaust valves are open at the same time) allowing fresh charge to flow through the chamber and out the exhaust expelling the remaining burn gasses. This of course also leads onto another issue...

e) Inlet / Exhaust pressure balance. Given that you need to drive the remaining gasses out of the chamber during the overlap period, the last thing that you want is for the exhaust to have a pressure greater than the inlet. It isn't going to do a wonderful job working against a pressure differential pushing exhaust gas back up the inlet! Exhaust design and turbocharger selection is much more critical on a 2.5 litre than on a 2 litre. Get it wrong and you will get MUCH LESS power from the 2.5 than the 2 litre, the 2.5 being "strangled" by the turbo unable to breathe with fresh charge being heavily contaminated and heated by residual gas.... result is that you cannot run anywhere near enough timing to get decent thermal efficiency. Sure you're moving air, but it isn't being used efficiently, might as well not be moving it in the first place!

That's a few of the basics that work against the 2.5 as compared to the 2 litre.... now it's not all bad news because the 2.5 will want to displace more air at the same boost pressure if the heads permit the flow. Or to put it another way, a 2 litre would require more boost to achieve the same airflow. If you have to compress the air more to make it flow then you will raise its temperature more, firstly through isentropic compression and secondly by compressor inefficiency.... more boost means more heat which you have to get rid of, ergo you need a better intercooler. Unfortunately, this heat doesn't just magically appear from nowhere.... it comes from energy supplied to the compressor by the turbine. More boost means more power needed by the compressor, which means more energy from the turbine, which means it has to extract more energy from the exhaust gas, which means that since the mass flow rate is constant the additional energy can only be taken from the exhaust gas by increasing the pressure ratio across the turbine wheel, ergo compound EGBP has to be higher for a given flow rate. This is of course in an ideal world, and assumes that the heads are no more of a restriction on the 2.5 than they are on the 2 litre but as we have seen above, that is far from the case. It is also possible, but not very common, that the compressor choke line limits the airflow at the raised boost pressure required for the 2 litre compared to that necessary for the 2.5, in a nutshell the compressor may be simply incapable of delivering as much air to a 2 litre as it can to a 2.5.... I have never seen this theoretical situation in practice though.

It's a complex balancing act. Some things work in the 2.5's favour while other work decidedly against it. In order to build a successful 2.5 litre you need to identify those aspects that are going to be the largest impediments to making the 2.5 efficient. If you can get the airflow, and you can make it efficient, you'll have a monster. Get it wrong and you'll have a dog. A 2 litre is much more forgiving of minor indiscretions, but of course will always languish in the shadows of the 2.5's awesome torque.... in the real world, an average 2.5 will leave a 2 litre wondering whether its turbo is working, while a good 2.5 will leave a 2 litre trying to find the anchor

Hope this helps,

Pat.

pat

Harvey,

I believe Mark has stated the MD321L is based on the Garrett GT30 "-12" core, which has a 56 trim T04S 76mm compressor and is rated to 55lb/min compressor flow. The closest map I can find at a glance is the GT30R map, which has a 56 trim T04S 76mm compressor and is rated to 53lb/min....



Cheers,

Pat.

ZEN Performance

The turbo still isn't producing the goods though pat, it's hard evidence. It's a shame, but it's true for now at least.

P20SPD

iTrader: (1)

Paul, wouldnt that be a little more accurate as:

This turbo still isn't producing the goods on this particular engine though pat, it's hard evidence. It's a shame, but it's true for now at least.

ZEN Performance

I agree, I should have been more specific, but with so few units about, we don't have much in the way of evidence to suggest what we should be getting.

On the other hand I easily managed 390hp with a different TD Hybrid rated at less power than the 321L, this was at less boost with a smaller (2.0 vs 2.13) engine too.

P20SPD

iTrader: (1)

Do you know what boost this is running?

ZEN Performance

boost at peak power was 1.45bar, power was 387.3hp but I am sure I saw a little more power on another run.

Jolly Green Monster

iTrader: (4)

is that the boost on the TD hybrid or the MD321L?

Simon

P20SPD

iTrader: (1)

Cheers Paul, just trying to get a feel compared to the boost Alan Bell's 2.5 runs to get 450, which is circa 1.6bar.

911

Reading Pat's (#37) input (so interesting and well expressed), is this why the 2.33 is favoured over the 2 and 2.5?
Graham

Peanuts

iTrader: (15)

^^^^ what G done said


(Having plumped for a 22t)

scoobysmiff

iTrader: (2)

Owen Developments - turbochargers, performance tuning and innovative engineering solutions

these seem to know a bit about turbos?

With this one in particular suitable for this thread

Owen Developments - Online Catalogue

Andy.F

What core was in your Garrett hybrid turbo John ? It was also rated at 450bhp IIRC.
Was it larger/smaller or the same -12 core fitted to the MD321L ?

Andy

harvey

iTrader: (48)

Mark : I want a turbo to take a step up from my TD05-06 20 G and if the MD321T is capable of providing over 450 bhp with not dissimilar spool, then I am very interested. Bearing in mind the current turbo is producing 420.7 bhp with more to come and that was the result on Optimax plus 2mls/litre NF, then good results can be expected.
I can undertake fitting the turbo on the car and getting it mapped. I know you won't have a problem with the Sigma ECU as you wanted to sell these earlier in the year and it is even more advanced now. You can be present for the mapping if you wish and have a copy of whatever data you want.
Obviously I don't want to go to the trouble of fitting a turbo, only to take it off again so the insentive is for me to get a good result, leave the turbo on the car and for you to get a sale.
What do you think? It gets you a turbo, tried tested and demonstrated in line with what you wanted and providing I keep it, I would obviously be happy with it and pleased to say so publically. This could go a long way to mending the bridges between us and burrying the hatchet so to speak. Win :Win for both of us.
Let me know.

dowser

Hi Andy - no idea what core it has, but it's bolted to my EJ25 now I'd guesstimate 320-330 at 1 bar currently.

Richard

Lateral Performance

iTrader: (20)

Harvey,

Thanks for the offer, but arrangements have already been made, and the results will be posted, so you'll be able to assess them.

I'm hoping that "mending bridges, & burying the hatchet, so to speak" isn't based solely on you being able to test the turbo ? Because that would be a pity.


Mark.

Maz

iTrader: (34)

Would indeed as well as being extremely cynical.

harvey

iTrader: (48)

No I was offering to buy a turbo providing I was happy with it and my approach to it was quite simple. It would be a great benefit to you if I was running one of your turbos.

P20SPD

iTrader: (1)

That just reads wrong Harvey.