For VWRacer re your race car

[VWRacer]

Thanks for the info, DVS8TR. DO you have a link for this? I would like to read more about it, especially if there are pics.

I suspect that the VNT25 would be a bit large for my application, but this same approach might work with a VNT15, which is a much better power fit to my engine.

[Spike_TDI]

As for the M90 idea, a very good friend of mine bought a M90 prototype kit off Monmentum Motors a couple years back(Never made it into production because it sucked total ass). It was terrible, it only did two things good 1) make noise 2) heat the air. I seen Wolfrocco's charger setup this weekend his car did the same things my buddy Paul's did. Make allot of noise and heat the *** of the air. The outlet from the charger was so hot you couldn't touch it.
A small Procharger would be cool though.

The T25 used on the 2.2L Dodge motors is fairly small. Don't confuse it with the GT25.

[TDIMeister]

Rootes-type superchargers, of which the Eaton family are derived, are notoriously INefficient devices.  Just because Mercedes and a handful of OEM use them doesn't make them God's gift to the earth.  Any car company needs to minimize costs, and business to supply components (whether superchargers or what-not) go -- almost without exception -- to the lowest bidder, unless there's political back-scrubbing going on, which also happens almost without exception.  I can say this since I work at a Tier-1 supplier.

A Lysholm screw-type compressor is far more efficient, but $$$$$$$$.

IMO, I would rather go with a two-stage Lysholm supercharger / turbocharger arrangement in series than a sequential turbo setup for a small displacement 4-cylinder engine.

[lord_verminaard]

Lysholms are indeed badass, but like you said, good luck finding one for a good price.  I've never messed with an M90 before, but GM had pretty good success with the M62? or M63?... whatever it is on the GTP/supercharged 3800 Series.  I dont think they used an intercooler on those either, and those big cars scoot along pretty well.  Anyway- I think what caught my attention the most about that M90/G60 setup was that it made boost at low RPM and made a lot of boost (or potentially did) at high RPM- While the M90 isnt ideal, like TDIMeister said, I think a charger/turbo setup in series would be a lot easier to control than sequential turbos, and packaging would probably be better (in VWRacer's situation anyway) as well.  You could have the charger on one side and the turbo on the other, which would probably have a better balance than two turbos hanging off of one side of the engine.  Trying to get two VNT turbos to do what you want them to do sounds like a lot of headache to me.  With a super/turbo setup, you probably wouldnt even need a wastegate on the turbo, if it was just the high-boost counterpart to the equation.  Either way, seeing a diesel with either two turbos, or a super/turbo setup would be a sight indeed.  

Brendan
84 Scirocco 8v
00 Camaro L36

[TDIMeister]

A screw type charger can pretty efficiently supply around 6-9 PSI of boost, the optimal level of which is determined by reading the peak efficiency of the supercharger and running on the low side of the efficiency island to minimize the parasitic drag of the supercharger, which subtracts crank HP.

In a steady-flow system like a supercharger is, the power required is equal to the mass flow rate multiplied by the integral of V*dP divided by the efficiency (hey, BlackTieTD, here's a primer for your math exam and a preview of Thermodynamics you will be taking at college   )

The turbo can then act as the second stage.  Let's take for example, a Screw compressor operating at 7 PSI (PR approximately 1.5).  The turbocharger acts on an additional PR of 2.3 (19 PSI), making the total PR 1.5*2.3=3.45 or a overall total boost pressure of 36 PSI  :shock:  :shock:  :shock: Is that enough for you??

[lord_verminaard]

As some of the confederate flag-flyers in my area would say: "Yeee-haw!"

 :lol:

Brendan
84 Scirocco 8v
00 Camaro L36

[BlackTieTD]

In a steady-flow system like a supercharger is, the power required is equal to the mass flow rate multiplied by the integral of V*dP divided by the efficiency (hey, BlackTieTD, here's a primer for your math exam and a preview of Thermodynamics you will be taking at college   )

i've been involved in a couple discussions regarding supercharger options for the G60, their individual benefits/drawbacks but i haven't gotten into the mathmatics of it all quite yet. (i will stay with the OEM charger on the corrado.. uber-ported g-lader yields immediate 12psi when you mash the pedal, peak 18psi or so. flat torque curve from 2000rpm to redline). i hope one day to drive a supercharged diesel but there are obvious stumbling blocks and fabrication involved there that are beyond my capabilities right now.

the entrance exams went pretty well this morning, i think i did well enough to get my foot in the door. hopefully i'll know for sure in a couple weeks and then all thats left is quitting my job, which i eagerly await  :lol:

[lord_verminaard]

Here we go:  http://www.bahnbrenner.com/bbmservices/screwcompressor.html

22+ PSI capability, over 80% efficient.  Very nice.  I think Brenner is using a Lysholm design and modifying it in-house.  But, at $2,500, it aint cheap.

Brendan
84 Scirocco 8v
00 Camaro L36

[TDIMeister]

Here we go:  http://www.bahnbrenner.com/bbmservices/screwcompressor.html

Thanks for the link, Brendan!  the Lysholm and centrifugal superchargers are the most efficient devices, and IMO are the only types of superchargers that should be used.

Where superchargers are concerned in a Diesel or multi-stage forced-induction setup, the boost should be used sparingly because every PSI of boost generated by the supercharger needs additional power that comes straight out of the crank.  In an engine where performance rules at all costs with no regard for fuel efficiency, sure, you can run as much boost as the supercharger can generate.  However, in an endurance race where a single fuel stop (or the lack thereof) can mean the difference between winning a race or not, you want to keep fuel efficiency at least somewhere in mind...

Turbocharging is by no means free as well.  The restriction in the exhaust give rise to added backpressure and therefore piston pumping losses.  However, in an efficient, properly-matched setup, the intake boost pressure can/will be higher than the exhaust backpressure.  The energy to raise the charge pressure comes not directly from the crankshaft, but from the enthalpy in the exhaust gas that would just otherwise go out the tailpipe.

Despite all this talk, we need to get back to earth for a moment and realise that the VW IDI motor will be limited by other things (peak cylinder pressure and thermal stresses) that need to be addressed before running boost levels that warrant an exotic setup.


Dave

[QuickTD]

Despite all this talk, we need to get back to earth for a moment and realise that the VW IDI motor will be limited by other things (peak cylinder pressure and thermal stresses) that need to be addressed before running boost levels that warrant an exotic setup.

My thoughts exactly. A single turbo can boost an IDI to destruction. Any efforts made in this area probably should be in lag and backpressure reduction.

[lord_verminaard]

Despite all this talk, we need to get back to earth for a moment and realise that the VW IDI motor will be limited by other things (peak cylinder pressure and thermal stresses) that need to be addressed before running boost levels that warrant an exotic setup.

My thoughts exactly. A single turbo can boost an IDI to destruction. Any efforts made in this area probably should be in lag and backpressure reduction.

I feel that you are correct in that statement.  But it keeps popping back in my head... wouldnt a charger/turbo setup be cool?  

I mean, REALLY cool???    

Brendan
84 Scirocco 8v
00 Camaro L36

[QuickTD]

I mean, REALLY cool???

Without a doubt...  

[matt_gti]

Despite all this talk, we need to get back to earth for a moment and realise that the VW IDI motor will be limited by other things (peak cylinder pressure and thermal stresses) that need to be addressed before running boost levels that warrant an exotic setup.

My thoughts exactly. A single turbo can boost an IDI to destruction. Any efforts made in this area probably should be in lag and backpressure reduction.

Bringing this thread back from the dead to say this:

Lower the CR, way lower, so you can run more boost. The twin-screw supercharger or Eaton TVS will provide boost at start-up/idle. One would need to determine the optimum CR plus supercharger boost to get an effective 22:1 or so that the IDI has as stock.
Result:
The Effective CR is the same as before, but with more air volume! Good startup and running, and allows more boost for more power.

The new Eaton TVS runs with a high thermal efficiency (up to 76%) across a very wide operating range. look at these compressor maps. awesome:
newbielink:http://www.eatonperformance.com/superchargers/TVS.html [nonactive]

here's my fuzzy math:
14.7psi times 1.5 PR @ Y CR = 14.7psi times 22:1 CR
solve for Y

I'm new to these diesels, but maybe if an 18:1 CR turns out to be successful, you can run 40+ psi total boost on the 1.6TD and break into the 200whp range. let me know what you think.