Anyone running a compound setup on a L-series

[Tony D]

Don't waste your time Ray, this ilk can't read what's written, no use trying.

 

I had an idiot in Japan argue what I went through Shaken-Sho inspection in a Suzuki Jeep I bought off him somehow illegally. We had installed a reed valve 360cc engine while that idiot had spent three years trying to duplicate the rotary-valve 360cc engine he had in there. He was convinced "those damn japs lied to me they said it had to be the (exact) same engine in there to pass!"

 

When I said "it is, it's an LJ36,"

 

He started screaming how it was NOT the exact same engine as what came out!

 

The old engine was in the back: "See! LJ36, it's the exact same engine!"

 

This guy just got more pissed off because his mental acuity simply couldn't comprehend "LJ36=LJ36"...

 

No matter which way you tried to explain it wasn't chicanery, he would have nothing of it.

 

He never would. There was a reason he was in mortuary affairs I guess!

[Six_Shooter]

I just looked and I have no idea where the post is, but I sent a string of pms off to the folks that have real world experience in such things. I invited you to read over the responses in on of those PM's with Tony. Have a read through it.

 

Thanks, I read through it and makes me want to continue with the compound set-up even more.

 

Nothing ventured, nothing gained.

 

BTW Tony, I can read just fine, it's funny how after I do the math, you change the subject, like you always do when you're proven wrong with math and/or verifiable data. Yet you never provide any of your own, only keep harping on this Electramotive car from the '80s, using anecdotes and stories of what people said, and this is somehow supposed to prove something. 

 

I guess the big difference here is that I'm not afraid to take a chance and possible waste time and/or money on something that may or may not work as expected, and you know what? Even if it doesn't perform as expected, I will be able to say I tried it, and learned something from it, instead of solely listening to other people who repeat something they were told from someone else.

Edited February 21, 2013 by Six_Shooter

[B. Whisky]

So what size turbos are we talking here, and what's the power band those in favor hope to produce?

[Tony D]

GT35R produced 2-3psi at any speed going WOT. Full boost of 17-25 was available like clockwork at 3,200. Depending on pressure, the basic R ran out of boost (stonewalled) at 7,000 up at 17psi, upping it to 21, only resulted in the same Hp being developed at 6,800, with power flat to the limiter setting at 7,200. Trying 25 psi, the upper rpm limit was only around 6,500, flat to 7,200.

 

I begged for a low boost run at 8 or 10 psi to determine actual horsepower peak, which should be in the 8,200 to 8,500 rpm range. Actually with the "X" replacement he is now running 21psi to 7,400 rpms and not running out of Air yet, nor is the power tapering off.

 

At 8psi, at 4,500 rpms this setup was making 380ft-lbs of torque and that was not torque peak. Everyone should remember that while the head flows 220CFM, the stock intake manifold Jeff is running drops that to only around 190CFM. The design exercise for quantification of what is possible on the stock L28ET Manifold is not over yet, but it's working fine to 7,400 rpms and 700+RWHP! One day the ITB's will be employed, that should uncork a few more horses as well, but require a bigger turbo for ultimate HP, or I project similar HP between 10-15psi, at a peak around 8,000 give or take. Should be a funner ride than now, and easier to modulate spreading out the power more like a larger N/A engine.

 

With the next larger model, there may be better power, but until we retest the X on the same dyno we don't know... The Ford Lightning MAF is running out of resolution, and comparing our PPH air intake, Jeff is really impressed at the increased flow the RX produced over the R in the target18-25psi range. Garret says the thing is capable of airflow supporting 100 more HP than previous model (GT35R)

 

From the MAF raw data (calibrated independently) we believe it!

As far as horsepower goals, Jeff wanted 600RWHP, but after my prodding and "over helping" he finds he's surpassed that and now it becomes a test mule for the Bonneville project, which requires horsepower in great reserve due to altitude and temperature during competition. We'll chart a peak on this setup, then simply build another engine with the uncorked intake and a bigger turbo with spool above 4,000 and turn up the boost! That should give us more than enough power for a Red Cap. At least I hope it will! So far testing has borne it all true. The Electramotive boys know their stuff, they have not steered us wrong yet! The ultimate power isn't really what they gave us, it was ancillary support systems where they really opened our eyes. Without that knowledge, the power becomes treacherous! Things want to go boom!

 

Jeff's engine, after all, is only a streeter. It's not competition spec by a LONGSHOT!

Edited February 21, 2013 by Tony D

[Six_Shooter]

For anyone actually interested in compound turbo set-ups, here are some links to some builds:

 

http://www.dsmtuners.com/forums/dsm-build-journals/426339-compound-turbo-setup-holset-style.html

 

http://www.dsmtuners.com/forums/custom-fabrication/336541-my-compound-turbo-set-up.html

 

http://www.skyroadster.com/forums/f25/lipsticks-800hp-first-lnf-compound-turbo-engine-build-36112/index10.html

[dylanh]

I've recently started reading about these setups as well and they seem very interesting although no one really knows how to match the two turbos its kind of just a guess and check thing. It would be really interesting on properly sized turbos so they are really running efficiently...

[Tony D]

I've recently started reading about these setups as well and they seem very interesting although no one really knows how to match the two turbos its kind of just a guess and check thing. It would be really interesting on properly sized turbos so they are really running efficiently...

That's patently false. The equations for sizing multiple-stage centrifugal compressors are well know and published.

Control is somewhat more complex if "efficiency" is the goal...but hen again there is arguably no reason to add this level of complexity with the currently-available wheel cuts in today's turbochargers. The single turbo can do far more than the one of even 10 years ago.

[TimZ]

That's patently false. The equations for sizing multiple-stage centrifugal compressors are well know and published.

Control is somewhat more complex if "efficiency" is the goal...but hen again there is arguably no reason to add this level of complexity with the currently-available wheel cuts in today's turbochargers. The single turbo can do far more than the one of even 10 years ago.

 

Agreed, but what I've observed from the build threads linked above is that it's likely true that the statement

no one really knows how to match the two turbos its kind of just a guess and check thing

 

 

...is likely a true statement for the population of people that are doing the builds.  They seem far more interested in creating the awesome looking bundle of snakes (and the fab work does look cool) than in how it actually performs.  If it works at all they declare awesome success.  Sorry, but 600hp from 47 psi   on a modern 4-valve 2.0 liter with a reasonable CR is not impressive.

Edited March 9, 2013 by TimZ

[Tony D]

Agreed!

 

Even Ford decreased complexity by running two compressors ON A SINGLE TURBINE to get better spool from lower MOI, and single compressor map surge line compatibility on their diesel.

 

Garrett ran true COMPOUND (not parallel) turbochargers with the first stage going into the second stage on a COMMON shaft. Then you just select wheels with,relatively similar performance islands and you get your pressure in inter cooled staging.

 

And 47 psi is the FIRST stage! That was what Garret was proof testing over 10 years ago. The actual compounds operated at less than 3:1 CR across each stage so their islands of efficiency were broader and the pressure across the whole turbo was still over 6:1 (100psi easily done on two centrifugal stages...inter cooled on only one stage you still get 180F air out f he second turbine with 104 in!