Evergreen billet K27/26-6 hybrid turbo impressions
 

A few months ago I sent a spare K26/6 turbo to Charlie at Evergreen to see what he could cook up. He had been wanting to try a trick lightweight 9-blade turbine wheel in one of these and mate it to a K27 compressor with billet wheel to see how it would work, so it was a perfect guinea pig. A #8 hot side would probably be more ideal for my use (this car sees a lot of track time), but I couldn't locate a good used one at the time, and we both wanted to see how fast the thing would spool, so we went with the #6. Charlie did port the turbine inlet and open up the throat as much as possible to minimize backpressure.

I finally got a chance to install it a couple of weeks ago, along with a SFR 3" downpipe and exhaust center section. Even though everything was "bolt-on," it was a bit of a wrestling match to get the exhaust to line up. I kept the water cooling circuit intact, and had to bend the hard water inlet pipe, install a shorter temp sensor, and extend the coolant hose from the expansion tank. But everything fit in the end, and I took the opportunity to install Siemens 80# injectors and Bosch 044 fuel pump at the same time, along with eliminating the factory hard pipes under the intake manifold. I even installed my Laust vacuum manifold that had been sitting in my toolbox for 10 years! I also installed a Saikou Michi closed-loop catch can and all LR black silicone boost hoses and J-boot, along with the factory airbox to keep things looking clean and factory.

I had previously installed and dialed in the VEMS engine management and a Tial 38 wastegate, and reconfiguring and retuning was a breeze.

I must say that I am very impressed with this turbo so far. Even with the factory headers and crossover, the turbo builds boost at 2000 RPM and achieves my WG spring setting of 0.7 bar/10 PSI by 2800! It is very torquey and fun to drive around town now, and still pulls hard to redline. I will install a gauge to check backpressure and post the results soon, but I'm stoked on how much this has woken up my engine, which is the original bottom end with 170K miles, and 10-12K track miles (I do have a spare engine that I will be building and fortifying for track use)!

Next up, dialing in the VEMS electronic boost control and going up to 1.0 bar!



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Looks great! Seems to come on boost as fast as my wee k26-6 does. Do you know what turbine wheel it is exactly, and will it fit in the #8 exhaust housing? I've acquired a hybrid turbo (vitesse stg 2) that needs to be rebuilt, and wouldn't mind putting in a newer better turbine wheel.

I think you'd need to ask Charlie @ Evergreen exactly what it is; I think he said he got it from Japan. But it should fit into a #8 housing as we were debating finding one and installing the turbine in that instead.

Very nice! It makes full boost at 2800rpm with the stock airbox? Amazing, I swear that airbox slows the spoolup down by 200-300 rpm.

Yeah, I am thinking that it might be a restriction, but one of my requirements was for the stock AFM and other stuff be bolt-on and bolt-off for CA smog purposes, plus it looks clean . . . . . I might experiment with a more open intake down the road.

I think the stock intercooler is the next cork that will be removed . . . . .

time for your VEMS' anti-lag function... :evilgrin:

Charlie just finished my k26-8 with that Billet wheel. I don't have as many upgrades as you but I should get it back on Monday, install it by Friday, and have some feedback soon.

Take it around the block with the air filter cover off and you'll see what I mean. For a while I ran a drop in K+N filter without the air filter cover and improvised something to keep the filter in place. Eventually I went with a MAF setup, but I know everything has to look stock for CA emissions.

You know what? I thought you had a stealth MAF attached to the airbox this whole time. That makes the spoolup of that turbo even more impressive!!

K26/6s spool quite fast. I have somewhat modified k26/6 and as you can see from the Mustang dyno sheet, it reaches 0.8 bar (11,7 psi) at 2800rpm (3rd gear), reaches 1 bar at 3000rpm and 1.15 bar (around 17 psi) at 3100 rpm, but can hold it (while remaining efficient at the same time) only up to 5200 rpm. This was with stock air box and air filter and stock intercooler (3 inch exhaust).

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I just installed mine with the Billet comp wheel but I still need to fix an exhaust leak by the wastegate before I can give my impressions. In terms of customer service, I can report back that he is top notch.

You can search my posts on more details about the turbo. The cold side has Bullseye drop in wheel - not the best option for a lot of power, but the wheel is light and helps with spooling and the hot side is machined to IIRC 54mm housing inlet diameter (48mm OEM, 56mm on k26/8) and has somewhat bigger wheel from some Audi turbo. In 2017 I did Stage 1 intercooler modification and did tune the car on street (the above dyno sheet is from first tuning where the car was on dyno for 2.5 hours and was really heat soaked) and the tuner said that based on the fuel amounts, the power increased in the whole RPM range by a good margin, but I did not recall what it was (something around 5 - 8%). Thus, the results above are quite understated (Mustang dyno & heat soaked engine after 2.5h on dyno).

I have the VEMS setup and I am very happy with it. The M-Tune also looks really nice, but at the end of the day a standalone speed/density setup like the VEMS is more flexible. It can run any type of fuel injectors or ignition setup you can throw at it, and changing settings/ re-tuning is very straightforward. Wideband O2 control and electronic boost control are built-in, and everything can be datalogged. I know that the M-Tune and Vitesse setups have some of these capabilities, but they are being piggy-backed onto a 30+ year old DME . . . .

I am building up a spare engine that will have some head porting work, but for now the new turbo is bolted onto my original engine, which has over 170K miles on the bottom end! I have not dyno-tuned the engine yet, but have done a fair amount of road tuning and it pulls well with good throttle response and AFRs throughout the rev range. I am only running 0.7 bar of boost so far, but I can tell that a freer-flowing head and intake tract would improve things even further.

For now, I am enjoying the excellent spool-up and midrange torque!

Update: I FINALLY got my car back from the bodyshop and got a chance to check exhaust back pressure. I was afraid that the #6 hot side would be too restrictive, even with the larger turbine and extensive porting done by Charlie.

I hooked up a Snap-On fuel pressure gauge to the factory O2 sensor bung in the crossover pipe (I have the factory exhaust manifold and crossover pipe, SFR 3" downpipe and exhaust center section, factory muffler) and did some high-boost runs on the freeway (could only do a few seconds at a time at full boost for obvious reasons). With an indicated 230 kPa manifold absolute pressure (about 19 PSI above atmospheric pressure), the backpressure gauge would peg at about 22-24 PSI. This was actually less than I expected, and was a pleasant surprise! I think I will still upgrade to a larger hot side in the future for track use, but this turbo sure is fun on the street!

I probably will not be able to get it on a dyno for about a month or so, but I will post the results here when I do.