Salt Slush Summer Reading. Chapter one - Turbo & Supercharger Matching part 1

It’s summertime. It’s vacation time. Sun is shining and the asphalt is warm. A perfect time for some Salt Slush summer reading. This time we will expand on our favorite topic, engine boosting. During the summer we will, in a couple of blog post go through the basics of turbo and supercharging without using too much mathematical formulas.

Why boosting?
The main reason for using turbos and superchargers is the low atmospheric pressure on planet earth. 1 bar (14,5psi) absolute pressure can only provide so much torque and power for a given engine displacement. No matter how much you play around with compression ratio, camshafts etc. If you want more than approximately 90hp/litre displacement (or 90hp/61in³) and 110Nm/litre (110Nm/61in³) a boosting device is the way forward. I guess if you read this you are more than likely to be one of them who want more power than a natural aspirated engine can offer. But how to start?


Gasoline engine Turbo and Supercharger matching
First thing to do, is to start thinking about how much power and torque you want and what kind of character you want from your engine. Ignore everything else to start with. 
No matter if you choose turbo or supercharger you need to start with figure out which peak power you want. 
Why? Because peak power relates to a certain airflow needed for a certain power and certain engine. 
Therefore, first step is to specify a certain compressor (or blower) size.

I write for a certain engine, because different engines will need different airflow depending on their configuration, i.e. how the combustion and gas exchange system are designed. If it’s a 2 valve or 4 valve engine, which bore x stroke ratio, compression ratio and combustion system layout (Port Fuel Injection (PFI) or Direct Injection (DI) etc.) and obviously which fuel that will be used.

Since most of today’s tuners are working on PFI engines, I choose to focus this first post on this type.

Example 1: A reasonable modern 4-valve engine PFI engine need approximately 850-900kg/h (31-33 lbs/min) of air to produce 300hp with a modest back pressure and good intercooling. This is not an exact value, but it gives a hint when it comes turbo matching. Obviously, 600hp would need 1700-1800kg/h (62-66 lbs/min) air and so on.

BorgWarner EFR 9180 turbo compressor map.

Then let's move on to a turbo compressor map of a modern turbo, with pressure ratio on y-axis (pressure difference before and after compressor) and mass flow on x-axis. The islands in the map show compressor efficiency and indicates how efficiently the compressor is in each speed-load point.

If we assume a pressure ratio of 2,8 and the air flow from the example above, we would at 95lbs/min get between 863hp and 920hp on premium gasoline fuel (RON 98 or similar). But this theoretical figure depends on several parameters. Among them knock sensitivity, charge air cooling efficiency, engine back pressure, inlet depression, cam timing and so on. 

Obviously, the more efficient an engine run at peak power, the lower boost pressure & air flow it needs for a given power.

Eaton TVS2300 Supercharger map

Lets move on to superchargers. The crank obviously drives a positive displacement roots supercharger like the Eaton TVS, but the matching process is similar to turbo.
You still have to determine which peak power you are looking for to get a supercharger that can deliver the corresponding airflow.

The supercharged engine more works like a natural aspirated engine, since it has no turbine blocking the exhaust, but on the other hand the supercharger takes energy from the crankshaft. 
This means that it all boils down to total engine and boost devices efficiency at peak power. The supercharger advantage is that it is possibility to play around with supercharger pulley ratio without having problem with lag. The basic function of any positive displacement supercharger is to provide more air than the engine can swallow and this, in combination with a direct connection to the crankshaft, eliminate the lag problem that is associated with high power turbo engine. (In coming blog posts we will talk about how to reduce turbo lag). What I mean is, that the penalty for driving around with a too big supercharger is not too severe.

Example 2: If we look at Eaton TVS2300 map above (which is the heart in many OEM applications and as well in Magnuson Supercharger kit) and recalculate to mass flow i.e. kg/h (or lbs/min) we would end up with at least 770hp (with more or less standard emission system and a standard cam)

 

The Magnuson DI TVS 2650R Supercharger

With this nice picture I end Matching Part 1. Stay tuned for more..    

Guests, Gasoline and Garage life



Someone has to make it happen. The spark has to come from somewhere. After that it's all about the fuel supply to keep warm.

Here's the scenario; Our garage neighbors sent an invitation via Insta to a social event and apparently she invited Gasoline Magazine as well. In addition, Josefine the next door event ignitor, sweetened the it all with a promise of free cold beer.  So, we showed up.

Sausages we sizzling on the grill, the beer was consumed cold and stories were told while the evening sun slowly turned into gold. Gearheads in harmony, that's what I'm talking about.  

Gasoline Magazine was there.  

There were eduacating lessons about Javelins.  

Ulf and Ragnar, The Master and The Trainee pictured.

The discussion;  Advanced sheet metal forming, shape and form.

Ringön, Gothenburg in the setting sun. 

Magnus in storytelling mode. Good to be in the audience.

Magnus Chevy AD pickup. 

He secretly chopped the top and surpriced us all.

Plymouth Roadrunner. A lock-up-your-daughters type of ride.

While most of us were going home preparing for work next day, there were other preparing for Gasoline Street Week…the midnight oil had to burn since there were a rear end that didn't work and there was just a few days left to the race.

We know the feeling...

Sunday morning...and more.

Our lives runs in turbo speed. We're supercharged. We have racing on our mind and we're working hard. Always. Our plan is to sleep when we're dead. At that point in time there seems to be plenty of time.

But still, even in this life there are these moments. When you can feel at ease. They almost always arrive on a Sunday. When you wind down. When the soul is free.  A shining sun serves as a support, But even a winter Sundays can provide peach of mind. In worst case it all turns melancholic...or balance in between. 

Here's anyhow the Salt Slush Sunday as of today.

Kalle took the Ford 32 roadster (with 354 Hemi) for a spin. He built this car several years ago and it still can make you afraid in a very positive way. 

Perhaps we were not so relaxed on the surface…Carina and I managed to fire up the old Olds Coupe and take it for a ride. Yes, there was an incident as always, but over all...a clear victory.

Other than that...



Sunday feeling part 1 by Johnny Cash

Sunday feeling part 2 by Velvet Underground.

The meaning of life? Could it be a Supercharger upgrade?

What's the meaning of life? Why do we want to move forward? Why make good things better? Why go fast?

 

All these relevant philosophical question are nice to discuss and think about.

 

But there's more to it. There's a Fever involved. A Fever that keeps car guys and girls wide awake at night. A fever that make hearts beat hard. There's no cure. Only temporary relief.  Reliefs that comes with a performance upgrade. When your ride moves from really fast to beyond imagination.  

Listen to Mike when he guides you through a Corvette C7 Z06 upgrade

 (to Magnuson TVS 2650)

 

Remark 1: Mikes C7 with Magnuson 2300 was one of the fastes cars I've ever experienced.

 

Remark 2: How Magnuson managed to fit the Eaton TVS 2650 supercharger under the Corvette C7 hood is a mystery. There must be a God of Speed that want bring piece of mind to C7 owners. At least temporary.

 

For the love of Racing! How to crave for hardship.

Racing in general; Exhausting. Expensive. Extreemly time-consuming. Add dry salt desert heat, blistering sun and uncertain weather conditions that can ruin it all, always. All located in a far away from Everything location. And basically no media coverage. That's Bonneville Speed Week.

So why do it? Why prepare for years to get there? Why withstand it all?

Because it's magic. The desert hardship brings out fighting spirit. Speed is addictive. The Epic salt desert brings poetic peace.

Right now the jetlag from the El Mirage test drive is wearing off while the crave for Speed Week 2019 is building up.

Still don't get it? You're not to blame. But have a look at the pictures below that Hans Lundblom just sent us...from Bonneville Speed Week 2018.

Powerful Swedish Steel under the Califorina sun. 

Anders.. 

...and Magnus while preparing the race car for Speed Week at Erik's & Ruth's Place in Califorina.

Seconds before one of the many races.

Paracute released after the last run 2018.

No remorse and no reverse. The race is over.

Our hero, help and guide to landspeed racing. Erik Hansson.

A man who knows how to burn midnight oil. But never learned how to give up.

Don Ferguson and Erik Hanson mixing nitro. Focus required.  

After race at Salt Flat Café. A good place to celebrate a birthday. Our friend, Rick Palagyi

Test Drive at El Mirage!

There's no guarantee in racing. Whatsoever. Effort can only take you so far. But still, we're engineers and we believe in analysis and testing rather than in faith and destiny. Therefore we've been working with our race car at Erik Hanson's shop in Orange and test driving the car at El Mirage. Purpose; get ready for Bonneville Speed Week 2019.

 

Let's talk about before and after. Let's start with before.

To start with we had to remove remains of 2018 Bonneville Speed Week from the Amazon. Salt and oxide.  Palm trees and the blue California skies served as a frame for our work with the 449 Amazon. The sun tan was for free too. 

To work in the close proximity of other landspeed race cars is inspiring and helpful.

Some need an after-ski drink. Salt Slush are more into after-wrench. We're here looking at Modelo wind down. 

Still in before mode. The 454 Suburban resting after fighting the Barstow hills. The old Burb still handles heat and hills and the combination of the two. 

For those of you that has not offloaded a race car in a totally quite desert where a wild wind is blowing 40degC (104 deg F) air...

...it's a memorable moment everytime. To some extent you get used to it, but still...it's mindblowing.  

 When silence is broken.

Advice: Look and listen at this video a couple of times.

The after; All dust must go. We're relieved and happy. The calibration is good, the car seems really fast. We're back at Erik & Ruth's Place, cleaning the race care, sorting up our race car

 

Next step: 2019 Bonneville Speed Week 

Epic. We're at Pomona Swap meet.

The early bird catches the worm. A saying that's not applicable for swap meets over a certain size. Like Pomona Swap Meet. Because it's not possible to see it all between 05.00am and 02.00pm. It's too big. There are too many impressions. No use to be structured. Just walk around and hope for the baragin/miracle to pop up around the next corner. 
In total 15 miles (24km) of booth after booth is painful and exhausting...but wonderful. If you're in to car and bike culture that is. 

Crap and Jewels all mixed. Stucture, confusing and creativity and one big melting pot. Here's a couple of pictures… 

Huge area. A lot of everything.

Talk. Haggle. Decide. Agree. Shake hands. I'm buying 97's carbs for my Ardun. 

Immaculate Cadillac.  

Gordini with sting. 

No blues. Just an Amazing 1950 Mercury Custom.

 

Some ride in comfort. Others carry the burden without notice.  Exitment and expectation as fuel.

Old style, modern heart. 

There are different ways to get attention. This is one. 

LS, Coyote, Hellcats...take a pick. 

Caballero, Buick Caballero. 

A truck? A Benz? No,a Mercamino! Dare to be different.

No rain. Not Cold. No heat.

Just a nice day at Pomona Swap Meet.