Which turbo is better, Garret or KKK?
 

I have a choice of turbos to use on the 617 engine I'm rebuilding/reassembling. I have both a Garret and a KKK so I was wondering which one would be a better turbo. They both look like they're it good shape.
What are your thoughts?

KKK spools faster and has an external wastegate adjustment.. ^_^

I noticed that on one of them.

the KKK spools faster but the Garrett has a higher top end while the KKK runs out of steam. plus IIRC you can switch the turbine housings and blades on the garrett with that of the SDL garrett.

Well I don't have an SDL turbo so I won't be able to try that one.

The KKK is better as a daily driver if you have no plans on increasing engine power beyond stock.

I think you should use the turbo that is in better condition, less shaft play.

does anyone have measurement of all the wheels for comparison.

We also should consider other turbos. anything with a standard t3 turbine inlet should bolt to the exhaust manifold. these turbos were designed 30 years ago. we need something modern. I really like holset turbos. I want to try an HX25 or HX27 or HX30 on a 617, they are used on Iveco engines. I'm looking for the quickest spooling turbo without sacrifice to the current top end.

Also a bigger, well designed, down pipe, like a 3", will make a drastic improvement. I will never forget the time my downpipe was cracked at the bottom flex section, this lowers back pressure, like a bigger downpipe. all I know is that the turbo spooled much faster and my 300SD easily got to top speed.

I'm sticking to the parts I've got on hand on this job so this car will be more like something to be a daily driver.

they are both very reliable. i would say garret for mods. kkk for outstanding proformance without mods.

Hmm, what sort of mods are we talking about?

Upgrading the compressor wheel and changing the turbine A/R.

Sounds $$$$ to do that. I was thinking something like turning up the boost.

It's cheap if you get the parts used.

The T3 is good to about 20psi IF you have an intercooler.
The KKK is good to about 14psi, at 18psi it turns into a heat pump.

Wouldn't 20 psi basically melt the pistons or does the intercooler do something to keep a meltdown from happening?
As far as upgrade parts, what would work and who's a good source?

20psi won't hurt the engine if you do it smart. Intercooler, Pyrometer, additional fuel, good exhaust, properly sized air filter, etc.

Any traditional T3 can serve as a parts source. The T3 from the 86-87 300D/SDL has a 50 trim compressor, the 3.5L engine has a 55trim and the turbo Mustang/Thunderbird/XR4ti have a 60 trim. Larger trim flows more air at a slightly lower overall efficiency.

Check ebay, there are parts on there all the time.