Choosing KRAS55Bi or KRAS55Ti... Bi Update 1,163WHP!

[Sales@KRATOS]

Choosing KRAS55Bi or KRAS55Ti

Since announcing pre-orders for our KRAS55 line of turbos, we noticed the majority of pre-order interest we've been receiving is for the KRAS55Ti rather than KRAS55Bi. As we understand the excitement behind wanting to purchase the highest output option available, we feel it necessary to further explain the differences between the two options so that consumers can make an educated decision before placing orders.

(Pre-order bearing housings in prep for final assembly)

KRAS55Bi

The KRAS55Bi was engineered and developed as our Standard Third Order Geometry Point Milled Forged Billet Wheel option to support an average of 850whp with supporting modifications and built engine. This wheel design was engineered through CFD (Computational Fluid Dynamics) to flow more lbs/min at a given pressure ratio than any other turbo system on the market for the BMW S55, as well as provide great boost response with minimal lag. As many of you have seen, the KRAS55Bi has exceeded those figures by leaps and bounds and has been proven to support 1163whp as tested. Rating our systems at an average of 80%-85% of their maximum output capabilities allows for consumers that may not have identical supporting modifications installed to produce at minimum our rated power output for that platform. KRATOS has been testing the KRAS55Bi on several beta test vehicles from time attack track cars to daily driven street cars throughout the past 2 years and over 30K miles logged without fail. Simply put, the KRAS55Bi is the best all around street/drag/track setup for the S55 that KRATOS has to offer.

KRAS55Ti

The KRAS55Ti is a marginally larger Third Order Geometry Point Milled Compressor Wheel option made from Ti6Al4V Grade Titanium. This wheel was developed for the long term HCF (High Cycle Fatigue) effects of 25 Hour Endurance Racing and Time Attack Racing. We were approached by the Race Team Strom Motorsports to develop a high output low heat alternative to the stock turbo system that continuously failed and caused limp mode issues during their NASA 25 Hour Endurance Races. It was at that point that we designed a Ti option that has 3-4 times the tensile strength of Forged Billet and could handle much higher cycles of constant variable load stress (HCF). We also made the wheel marginally larger, not so much to produce a higher maximum power output, but to reduce outlet temperatures on the compressor side at a given boost pressure. This helped completely negate the issues Strom Motorsport constantly had to deal with regarding high heat limp mode.

Unfortunately, the increased density of the Ti material does increase weight to almost double that of an identically designed Bi wheel, which in turn increases lag and slows down transient response of shaft speed. As a result of the increased weight our engineers were left with the task of trying reduce the increased lag and reduced transient response. Fortunately, the higher strength of the Ti allowed our engineers to take advantage of the metallurgical properties of the titanium material and be much more aggressive with the design and blade/hub root thickness. This, in turn, also helped reduce overall weight. The result was a tremendous difference in transient response and reduced lag over an identical copy of the Bi wheel in the titanium material. Another characteristic of the Ti is that it has a much lower rate of expansion as compared to Bi. This allows for much tighter compressor to wall clearances which results in helping to negate increased lag due to the larger size and weight of the titanium material. We rate the Ti conservatively at 1000whp capability, but are currently beyond the limit of the Dodson Sportsman Plus Clutches with the Bi at 1163whp. That being said, we are awaiting their new Promax Clutch System to be available for beta testing before we can fully test the maximum output capabilities of the Ti.

Summary

Now that more detailed information regarding the two options is available, customers can have better understanding as to what options best fit their needs. We feel the Bi version is the best all around option for daily drivability, weekend track use, 1/4mile, 1/2 mile, etc. The Bi also produces less lag and better transient response than the Ti. Of course the Ti has the capability to produce more power, although that was never the intent for the design, it comes at the expense of increased lag and transient response. Keep in mind that endurance race cars very rarely operate below 4krpm engine speeds. Therefore, the lag and transient response issues are really a moot point for their application.

Most S55 owners are yet to experience the challenge of controlling this platform and putting power to the ground with the current output levels of the Bi, be it on the street or the race track. More power isn't always the answer as this can compound the problem and only make matters worse, especially on a rear wheel drive platform such as this.

Updated KRAS55Bi Results

As many of you know, during previous testing with our KRAS55Bi we were able to achieve 1150whp/985wtq @ 41psi in 75°F ambient conditions. The original data that was collected during this dyno session led us to believe that the drop off in power after 6300rpm was quite possibly related to limitations with valve spring pressure on the valvetronic side and/or stock camshaft profile limitations. To assess this issue further, we have been busy tuning on the dyno with Halim@HCP which helped realize the true underlying cause. The addition of the 4 Bar Map sensor added to the equation and required more time on the dyno dialing in the car as well. What we concluded is that we are in fact beyond the flow capabilities of the KRAS55Bi rotor group @ 41psi to sustain the power from 6300rpm to the rev limiter. However, we're not reluctant to admit that our original assessment was incorrect as we're still very pleased with the capabilities of our KRAS55Bi turbo system and newly collected data from our latest dyno sessions listed below. We feel many of you will be pleased with data as well!

This Dyno run of 1066whp/883wtq was produced @ 37psi in 92°F ambient conditions. The boost values for this dyno run is where the adiabatic efficiency of the KRAS55Bi shines while power continues to climb to the rev limiter and provides a nice, clean, and repeatable graph even in hot ambient conditions. We also feel the graph could have been even cleaner and would have made more power had ambient conditions been a bit cooler. All in all, we are very pleased that a system we rated as capable of 850whp can easily produce over 200whp more at a very consistent level.

This Dyno run of 1163whp/983wtq was produced @ 41psi in 77°F ambient conditions. The purpose of this dyno run was to produce a balance of maximum output capabilities of our KRAS55Bi system with the least amount of drop off compared to higher boost levels.

The overlay of these 2 graphs provides a good example as to how the KRAS55Bi's both at 37psi and 41psi end up at the same power level of 1050whp once 6600rpm is reached. However, the 41psi map does produce 160whp/140wtq more @ 6300rpm vs. the 37psi map.

Pre-Orders

Delivery on pre-ordered sets is right around the corner! We are currently accepting $500 pre-order reservations for the KRAS55Bi turbo system. Our anticipated ship date is the week of April 15th. There is limited space available for pre-order reservations at the moment.


Please contact info@asrkratos.com to reserve your KRAS55Bi turbo system!

(Pre-order reserved KRAS55Bi bearing housings prior to final assembly)

[CT92F80]

Yummy!!!

[chetrickerman]

Love it. 1066 whp is awesome!

[papasmurf_m3]

Thank you for the update! Will the KRAS55Bi be available on the shelf at some
Point or is it always pre order?

[MR RIZK]

Since I only want 600hp can I get a 40% discount..

As always a detailed write up.. 👍

[Sales@KRATOS]

Originally Posted by AlphaPro_F80

Thank you for the update! Will the KRAS55Bi be available on the shelf at some
Point or is it always pre order?

KRAS55Bi's are scheduled to start shipping within the 3rd week of this month. As stated, pictures above are of pre-order turbo systems being prepared for final assembly.

For the short term, the pre-ordered systems will be the first out the door. However we have the raw materials in hand necessary to stock our shelves and are scheduling their final machining and assembly. We decided to expedite a portion of these to use as our pre-order sets as we know that some customers want to have their set of KRAS55Bi's in hand ASAP. After this first round of pre-orders, inventory for at least 6 months of projected sales will be kept on the shelf so as to assure that we can ship to customers within 48hrs of their placing an order without running the risk of backorders.

[papasmurf_m3]

Originally Posted by Sales@KRATOS

KRAS55Bi's are scheduled to start shipping within the 3rd week of this month. As stated, pictures above are of pre-order turbo systems being prepared for final assembly.

For the short term, the pre-ordered systems will be the first out the door. However we have the raw materials in hand necessary to stock our shelves and are scheduling their final machining and assembly. We decided to expedite a portion of these to use as our pre-order sets as we know that some customers want to have their set of KRAS55Bi's in hand ASAP. After this first round of pre-orders, inventory for at least 6 months of projected sales will be kept on the shelf so as to assure that we can ship to customers within 48hrs of their placing an order without running the risk of backorders.

That's awesome !!

[Sales@KRATOS]

A couple of extra pictures of KRAS55Bi components in the process of machining and final assembly.

[z33c]

ok you got my attention here. where do I sign up for a set of these to try out?

[Sales@KRATOS]

Originally Posted by z33c

ok you got my attention here. where do I sign up for a set of these to try out?

PM Sent!

[BadM4]

Originally Posted by Sales@KRATOS

PM Sent!

Pm me too please

[AlexNFH]

And me too ;-)

[Sales@KRATOS]

PM's sent to both!

[Dino_f80]

Originally Posted by Sales@KRATOS

PM's sent to both!

Can you pm as well im definitely interested

[Sales@KRATOS]

Originally Posted by Dino_f80

Can you pm as well im definitely interested

PM Sent!