komp55

This may be true, but the statement I commented on didn't specify the results as being solely from Kleeman mid-length headers. Shorties alone are not going to yield the claimed power. Nobody should want to drop $3K or more on a good set of shorty headers (not manifolds) and then be disappointed when the majority of the obtainable gains (as stated in the post) aren't there to be had.

Yacht Master

Actualy you want turbo lag on a coumpound motor. Remember you are on the supercharger at the bottom end and turbo only at the top end.
In my opinion the thick wall steel HEM would be a great canadate for a turbo install because it lends it self to easy fabrication and mounting of a turbo flange, it is the best suited part for this to date.

For a turbo only motor you are 100% correct small tubes higher velocity quicker spool up.

jangy

I'm sticking with the primary cats for now. I'm just too paranoid about all the O2 issues and getting the CELs.

I want to have a custom connection made just past the primary cats and O2 sensors. Then, I will get bent pipes that bolt to it and go to the mufflers. I will have an option add spots for an X pipe (where the resonator was) and a cut out pipe. HELP!!!

stevebez

Yep - I was thinking turbo only... have to say I think a compound setup is overkill and pretty complicated, let alone limited by space... particularly for intercooling. Also not mad about blowing turbo boost onto the S/C screws... heat + more heat dunno not a great recipe. A turbo only is ideal to me. Remove the S/C screws keep the S/C pulley in place so ECU thinks S/C is still there and everything will look almost stock too... some low mount cold air intakes, some turbos where the primary cats are, custom twin intercoolers where the OEM air boxes / filters are and viola... you're golden.

You could even remove the OEM I/C in this setup...

Sry Jangy getting a bit O/T here...

Yacht Master

I know it sounds and is complicated, But we have the most important part done, the blower bypass valve, this would allow the supercharger to come off line totally (+60 to 70 hp) and the turbo takes over, torque everywhere My point of view is from the marine engines and having a V16 twin turbo then after-cooled, with a bypass blower, followed by an inter-cooler, engines, that I see and use almost everyday distorts a guys reasoning. Even the little boat engines down the street are beginning to build some custom compound engines.
http://www.chiefengines.com/
Sorry for the off topic, somebody's got to do a turbo sooner or later, Jangy.

stevebez

Will the Turbo feed not also be pushed through bypass valve though?

chiromikey

if you're going to remove the screws, you may as well go the next step replace them with laminova i/c cores or something and turn that newly hollowed out hunk of metal into something useful.

jangy

No problem on the turbo OT. I would consider it, but it would have to make a major difference. From what i am gathering, you guys want to add a turbo setup as a piggy back to the OEm SC. When the turbo spools up, the SC psi will get dumped into the bypass and the car will literally run on TT? If I am even in the ballpark, then I have a few questions before I do this.

Is it true that the diminishing returns on the SC are in the actual volume of air they can handle? Basically, does there come a point in the band where the airflows faster than the SC can pump? OR is it that the drag from the SC begins to show itself?

If the issue is airflow, would the TT setup have a solution, or just work by pushing air? Will it go through the current SC plumbing? Is the porting wide enough? Do the ports need to be tuned for proper flow and lag?

Last, why not dump the SC and go TT or replace the SC with a more efficient version (my preference)? CF trubine anyone?

HYEPWR

Let me try and answer your questions...

Twincharging(Turbo+SC) is the best of both worlds. the supercharger compresses the the air directly above it. It doesnt care if that air is at 5psi ...14.7psi(atmospheric preasure) or 20.7psi(TOTAL preasure above the supercharger blades with the perposed 6psi turbo boost).

So the turbo boosts the air 6psi....that 6psi (~Preasure ratio 1.4)air now gets compressed even further by the supercharger (13psi is ~1.9 preasure ratio). Since the supercharger compreses by 1.9 whatever air is above it--the final boost is not 13 + 6 =19 psi ---the boost is now 1.4 x 1.9=2.66....so the engine see's a preasure of 24psi!!

As I understand it---there is a valve at the supercharger inlet. This valve opens during vacuum situations to bypass the s/c and increase fuel economy. Some are suggesting that electronics are used to open this valve at say 4500 or 5000rpm while silmiltaneously getting the supercharger clutch to disengage. What will be left is pre s/c pressure --which in this case -is turbo pressure.Personally I feel the tuning will be very complex as the MB systems are intertwind(or not who knows unless you've completely mapped the ecu).

Shortcomings of twincharging..

Unfortuneatly the supercharger needs more torque to compress the 6psi air, so it will have to work harder. Furthermore--a more heat will be created. for example on a 70 degree day the output from 6psi turbo is only 90 degrees....not that high but the senario get worse when we now use that 90 degree air as the starting point for s/c compression. after the s/c gets through with its compression---we see supercharger outlet temps of 218 degrees!! in other words--- the problem of heat is much more compounded with a turbo feeding a s/c ...no matter how efficiant the turbo. SLR type IC's are the only solution...unless you drive in Alaska only.

Benifits

why turbo + s/c?

In our cars(or any where the S/C is online the whole time)....the turbo is just adding boost that the s/c cannot. imagine a HUGE pulley. With 6psi extra boost the total at the piston would be 24psi....since we see ~10rwhp with each psi---I would expect at least 110 rwhp with a 6psi turbo. So 600 to 625rwhp.

Adjustability----with a controller you can set your boost from 2psi to whatever at the turbo....in other words---with 116 oct gas we could boost to 35psi and gain 250rwhp...

alll theory till someone slaps one on their $50k car