617 Turbo : KKK or T3 Is Best & Why ?
 

I'm tinkering on my late 1984 graymarket (CWC, thanx fellas) and it has a KKK turbo on it, I'm getting ready to install original non E.G.R. intake & exhaust manifolds and am wondering if there's any reason to retain the KKK turbo or replace it with a Garret T3 I plan to overhaul .

Thoughts ? .

TIA,

Done both.KKK comes on sooner,fades out by 65mph,3 miles per gal. less at higher speeds. T-3 turbo comes on later,better for higher speeds.
Have ported both,did help both. Impressed with kkk after porting at lower speeds.

KKK Turbo Details
 

?? Why / how does it 'fade out' at 65 MPH ? .

By 65 m.p.h Exhaust back pressure becomes too great. Exhaust through
turbine becomes too restricted.

T3 turbo rebuild kits are dime a dozen and readily available.

If your curious about turbo options I'd suggest you have a poke around here.
STD

?!
 

I assume here you're unaware that the Mercedes muffler and resonators have NO RESTRICTIONS in then whatso ever.....

Seriously .

Yes, I've personally looked in one end and you can see straight through .

Thanx for the STD link, I'll go peruse that ~ I bought a nice overhaul kit from G-Pop Shop *but* they can't seem to sell me an impeller ~ they want a "tag number" and not a single T3 I've ever seen has nay tags on it....

I really appreciate the help and ideas here .

I assume here you're unaware that turbocharger turbines cause backpressure....

The KKK having more restrictive wheel/housing meaning Exhaust Manifold Pressure gets too high. To be honest both the KKK and the T3 have this issue. HX30 all the way :P

THANK YOU !
 

I'm still learning here, I don't understand how an open exhaust has any back pressure .

The turbo creates back pressure in the intake manifold, unless you loose that pressure there shouldn't be any speed related loss of boost/ power ~ I've run the car wide open and discovered no loss of boost so I'm tying to understand this but failing .

The engine runs fine, sweetly in fact and now I understand why this heavy wagon takes off faster than my lighter Coupe .

Any exhaust pipe can create back pressure depending on the gas flow rate.

Nate,

The KKK K26 spools a bit quicker than the Garrett. All else equal, I prefer the KKK for Los Angeles driving, as that power comes on sooner for stop and go/slow and go. It also has an externally adjustable wastegate which is easier to access.

I’ve had my 300D up to about 115 GPS verified mph with both turbos and though the KKK runs out of breath a bit sooner (seat of the pants says about 4000 RPM vs 4400 RPM for the Garrett), at freeway speed it doesn’t matter.

YMMV, this is on a very healthy motor with an even 380-400 psi/cylinder.

O.K. then ;

I'll prolly stick with the KKK turbo since it seems to work O.K. .

The wastegate adjuster has maybe 3/4" clearance to the body making it not really easy to adjust I think, I've gotten pretty fast at the T3 boost adjustment, I use a pair of 8 X 1.0 MM Pal Nuts on the end of the pop valve and am reasonably fast at getting that damn spring out and back in again too .

I should hook up the GPS and see just how fast it will go .

T4 compressor with a T3 hot side. Works for me and more is better (sometimes). It does come on late, though......


Dan

Options
 

THANX Dan ! .

As I drive a lot in traffic the late boost is a non starter for me .

I also dislike the Diesel Smoot on the cove, no smokey joe for me thankyouverymuch .

The turbine spins from hot and pressurised exhaust gas. Eventually the volume of exhaust gas can become too great to get past the turbine, and back pressure builds between the pistons on their exhaust stroke, and the turbine. This is known as Exhaust Manifold Pressure, and if it gets too high, it could potentially lift the exhaust valves on the cylinders with them meant to be closed. Some people believe that turbos run on "free, otherwise wasted energy" but this isn't quite true.



:)