Hello, myname is Alejandro (Alex) Regueiro. In early 1997, having previously been Senior Engineer responsible for the prototype build and durability development of the 2.0L engine family at Chrysler, I was hired to lead a small team of 4 Engineers in performance and durability/reliability development of the 1.6L Tritec engine. Having recently acquired the “Cooper S bug,” I finally purchased a supercharged R52 last week. Prior to purchase, I watched several very informative youtube videos from “ModMini” and exchanged some communications with him. That’s when I stumbled into this forum. It’s been great reading so much from owners, modders and tuners about the engine that I helped to develop so long ago. Since part of my responsibility was the durability/reliability development of the engine, I was very pleased and amused when someone in an old thread referred to the engine as the “Unbreakable lump!” Hence the username.

It’s good to see that there is a lot of great information and practical experience that is freely shared on this forum. OTOH, there are also some misconceptions about the design, development, technical specifications and history of this engine still floating around. Over the next weeks, I'd like to write a series of posts detailing the history of the engine, how it came to be, and get into more the technical details of the engine design and development,explaining why things are designed the way they are and hopefully answering your questions (keeping in mind that it’s been over 15 years since I last worked on this engine). I also hope to learn about the real world experience of owners and tuners of the engine.

So that you know where I’m coming from, here is my linkedin profile and a link to the SAE paper that I authored and presented at the 2001 SAE World Congress on the naturally aspirated version of the Tritec engine used in the Dodge Neon for European and Latin American markets .

https://www.linkedin.com/profile/view?id=AAMAAAKrPJgBTwxSnJFKqNtn5IYMfagTsNszc5A&tr k=hp-identity-name

http://papers.sae.org/2001-01-0330/

In the link to the SAE paper, you can now preview it on the right side of the page. So you get to see a few cool pictures and some data for free.

On a more personal level, I've had the British sports car bug from birth, as my Dad had both an Austin Healey 3000 and a Jaguar XK-SS when I was born! I've owned an MGA, a few AH3000's and E-Type Jag. Now a Mini. You can only imagine the excitement that I felt when I was tasked to develop the engine for the new Mini back in 1997. What a thrill! Best and toughest job I've ever had.

 

Welcome! I'm sure many of us are looking forward to reading your articles. Hope your new year is going well.

 

Amazing!
First and foremost, thank you! Second, I'm very much looking forward to your future posts.

 

Interested to hear your take on solid crankshaft pulleys

 

Welcome.

Frank S. ( Original Designer for MINI R50 ) was on the forums last year. Nice to see people coming to the forums.

Post up more info on the tri tech and how much of it was mitsubishi sourced , if any , heard a rumor?

 

Münchner Technologie Zentrum white paper entitled "The MINI Cooper S Powertrain", available in both English (no figures) and German.

 

Welcome to NAM, Alejandro! Glad to have you aboard. I've always wanted an Austin Healey!

 

Hi ECS - Mitsubishi had zero involvement in the Tritec program. They didn't build any part of the engine or have any involvement in the design. Perhaps the rumor started because Chrysler and MMC did use the same 2.0L DOHC engine in the mid 90's, (designed, engineered and built by Chrysler) but that engine shared nothing significant with the Tritec (that I know of), except maybe some sensors and fasteners. I will post up some more info. on the Tritec in the coming weeks.

 

Interesting! Thanks for sharing. I hadn't seen it before. I'll write more about this in the coming weeks. I'll say right now that the authors of that paper had nothing to do with the design and development of the long block S/C engine. They may have had some involvement in adapting the supercharger and the induction & exhaust systems, although I don't recognize any of their names and I worked very closely with the former Rover guys in Longbridge on the development (the S/C variant was more of a collaboration than the base engine), but all of the developments described in the paper concerning crank, pistons, oil pump and port flow and emissions were done by Chrysler. The exhaust port flow increase in fact was my own personal project.

 

Hi Bavmotors,

This is way outside my area of expertise but I'd think that it would be hard on belt and the timing drive system as the pulley is a harmonic damper (as I'm sure you know). I can't imagine it being a problem for the crankshaft in the HPD (we called the supercharged engine the High Performance Derivative) as the crank is bulletproof, being forged steel. I wouldn't do it on the base engine, as that has a nodular cast iron crank that might be overstressed without the crank damper.

 

Here's a cross section of the naturally aspirated Tritec engine used in the Dodge Neon (different intake and exhaust manifolds from the Mini). I don't have one of the Mini


Here's a little something to whet your whistle!

 

I look forward to your insight.

There is another MINI forum that has a VERY strong 1st generation following you might want to check out. I won't post the URL but PM me and I'm happy to share.

 

Interesting. Look forward to it. Do you know much about the Eaton SC development ?

 

Wow. I very much look forward to your contribution and your take on some of the conventional wisdoms that have become gospel. Welcome!

 

Yes, I know a bit about the development of the Eaton M45 proper and quite a lot about the adaptation to the Tritec engine, as my job was to conduct performance and durability development of all Tritec engine variants. So I had one engineer dedicated to the HPD engine development. Of course there were several other design engineers working on the components, like crankshaft, pistons, rods, water pump, etc. We tested a lot of different things, like different pulley ratios, water to air intercoolers and even an IHI Lysholm screw compressor. I'll get into the adaptation in a later post, but here's something about the Eaton Supercharger proper:

Eaton developed the M45 in house so the base unit, (minus water pump drive) was an off the shelf Eaton item. I'm not sure if they were the originators of the twisted rotor for a roots blower (they may have been), but they did a fine job developing that and the rotor coatings to increase the efficiency (know as isentropic or adiabatic efficiency) and reduce the noise. One of the main purposes of the twisted rotors is to reduce the characteristic beat frequency of straight rotor roots blowers. The other is to be able to have the inlet and outlet configured diagonally or longitudinally (wrt to the rotors) rather than perpendicular to the rotors. This is very important in an automotive application for packaging reasons and lent itself well to the R53 package. It's possible that some of these advancements in the Roots design were assisted by previous OE manufacturers who'd been using Eaton blowers for years (e.g. GM).

As you know, mid way through the R53 production, a new rotor coating was introduced. I believe Eaton called it the Gen 5. This increased the efficiency about 2% if I recall correctly and I believe the intention was for the rotors to "wear into" each other with the new coating to improve sealing (the cause the of the efficiency increase). Those two small slots just behind the wedge shaped outlet on the supercharger are also there to reduce the pulsation noise. Reducing that beat frequency is super important in automotive applications as pulsations like that can lead to the excitation of body panels in the vehicle which result in an extremely annoying drone.

BTW, the reason the Roots is called a "blower" is because it's really an air pump. The design has no internal compression. This is why they are typically only effective to about 2.1:1 pressure ratios. The Lysholm screw types have internal compression, meaning that the air is compressed by the interaction of the rotors with each other. Typical Lysholm screw compressors have internal compression ratios somewhere in the 1.3 to 1.6:1 range and can perform well up to about 2.6:1 pressure ratios (in automotive applications and depending on the internal compression ratio). The disadvantage of screw compressors is that they are still compressing air when in bypass mode (unless the drive pulley is clutched), so they have a higher parasitic loss when in by-pass (which is most of the time).

 

Nice, thanks for the R&D info. Yes , know about the coating. Its funny they considered water to air and IHI. I guess the eaton M45 fit the engine bay the best and was the newest small blower ( GM developed ) at the time. Why the water pump driven by the supercharger vs. belt ? I know they went to the EHPS PS pump because to reduce strain on the engine. Otherwise is would be another main belt driven accessory.

I have 250K+ on my 2005 Tritech ( N/A) , its been holding up well.

 

Hi ECS. Glad to hear that your lump is unbreakable.

Just to clarify, Rover/BMW did not consider a water to air intercooler. Chrysler Engineering ran one in our dyno cells to better control the IAT and understand the fundamentals of the technology better. IOW, it allowed us to more effectively do our work. Rover/BMW also didn't consider a Lysholm screw compressor. That was a side project that we did at Chrysler.

The EHPS went to that route simply because it was a more effective solution for the HPD than to try and drive it with the accessory drive belt. I don't think we could come up with a belt routing and PS pump mounting location that would work to drive everything and it would have likely needed an additional belt.

As it was, the base N/A engine had a tandem PS/water pump. That design was all new and quite innovative. One of my closest colleagues on the project has 3 different patents on it. Once the S/C came in, it displaced that PS/Water pump combo unit and a new solution had to be devised for both the PS and water pumps. That was one of many big challenges in designing and packaging the HPD into the Mini.

 

yes, and the bottom of the engine against the side wall is already tight. You had to fit the biggest engine in the smallest Frank S. Design.

 

Thanks for doing this. I expect it will be very interesting. I hope I'll be able to wrap my head around some of it.