There are many factors in how 20psi is ok.
1. Direct Injection
2. Small piston bore
3. 20psi is only for a small part of the RPM band
4. Direct Injection....and 10.5CR

1.You need to understand why DI is so good, and why this changes the rules as to how an engine performs. In a normal port injected engine, the fuel is sprayed into the air stream as it passes by the injector and atomizes (some what), the valve opens and the air/fuel mixture gets sucked (NA motor) or pushed (Boosted motor) into the cylinder. Then this mixture gets compressed. As the mixture gets compressed it heats up. Because there is fuel in the mixture, as it heats up, the potential for detonation/knock increases. As you compress more air into the cylinder,or run a leaner/hotter AFR, or the charged air temps go up, you run a higher risk of detonation.

In a DI motor, the fuel is being injected in the cylinder. So as the air is pushed/sucked into the cylinder, the air is compressed and heated up with no fuel in it. Then the fuel gets injected, then the spark fires it. The fuel is injected in the compressed air and atomizes very well before the spark ignites it. Because the fuel is not mixed with the air before it gets compressed, the chance for detonation to occur is greatly reduced. In fact significantly reduced.

In a port injected motor, under high loads in a boosted engine, the Air fuel mixture greatly effects the chance of detonation.

2. The smaller piston bore means less actual force on the rods and bearings. Meaning if you have an engine running 20psi, with a bore of 80mm, and an engine running 20psi with a 100mm bore, the actual force being applied to the rod and bearing is much less in the smaller bore engine. This is why a smaller engine needs to run more boost to make the same power. So the durability is not relative to the amount of boost, but rather many other factors.

3.Even with that said 20psi is only for a small part of the RPM band. 20psi starts at say 3000, then tapers to 14-ish psi by redline.

4. Ya, all the DI stuff i talked about, then throw in high Compression ratios. CR on a boosted engine normally is in the 8.0 to 9.0-1 area. This is due to the limits of octanes of fuel we have. On a normal port injected engine, it comes down to the heat built up as the air and fuel mixture compresses. A higher CR means more heat as the mixture is compressed, and again makes for potential detonation issues. So this means that more boost or a higher CR can be run without the risk of detonation. A higher CR means more torque can be had from the engine so why not run it if, the fuel allows it. DI is kind of like running race fuel, in that you significantly reduce the potential for detonation.

There is soooooo much more to EXACTLY how this works, pressure wave of the ignited fuel vs. crank angle plays a big roll, ignition time.............. but those are the quick notes that should make more sense.

Aluminum block has NOTHING to do with it. Guys thinking aluminum blocks are bad, are either die hard R53/EVO/Eclipse guys (Iron block aluminum head engines) or are old school V8 guys (nothing wrong with either option). All aluminum engines (with iron sleeves) have been around forever and hold up just fine.

Lean AFRS are normal in stock form on these cars also. Again back to the DI motor. Since the fuel is being injected when it is, and the heat in the cylinder doesn't have as much effect if detonation occurs, leaner Air Fuel mixtures can be used. And as we see in stock form the car runs very lean under load. Obviously done for fuel economy.

 

I have no doubts or misunderstandings of how DI works, just doubts that it has as large of an effect as you are saying it does. Time will tell I suppose .

 

Thats exactly the info ive been seeing around the net on the subject. My car is not audibly pinging so im honestly not too worried about it. There seems to be a lack of expert opinion on direct injection in general, so I have to draw my own conclusions from all the info thrown at me.

This is my take on all of this:

My car has NO pinging
It runs awesome
Definately has more power
Air fuel ratios might be a little lean but with DI its totally ok

Im definately not worried about longevity


So if you don't own an R56, and you really dont follow threads about them, and you didnt generate the dyno, AND it's not your car, how exactly can you make your point valid? Information should always be taken with a grain of salt, but the guys from ALTA seem to be the closest to experts I can find on this subject, so I dont see how any of your info that was posted is helpful in anyway. Its almost like your bashing a product you dont own and dont have experience with. Thats just my 2 cents though.

 

I don't need to own something to pass judgement on it. I don't own a lot of things, that doesn't mean I can't use what I know about it to make an informed decision.

Case in point, I'm a pilot, if I told you that a plane doesn't need wings to fly, would you believe me? You're probably not a pilot, I know more about aerodynamics than you do... But does that mean that you'd believe a statement as ridiculous as the one I just made?

I'm not bashing any products, just providing information. If it works as intended for you, then that's all that matters. It sounds like you've done your own research and come up with your own data... so be it .

 

well alrighty

 

*Hands over the *

 

Not true at all. Knock sensors listen to noise, and they ABSOLUTELY can pull timing before they knock. All modern day ECU's do this. They look at knock sensor voltage and internally have a voltage that equals knock at different RPM's. If the sensor reads close to this threshold it pulls some timing to combat Knock from happening.

DI doesn't cool things down, in fact the EGT's we see on both old an new and even other cars is basically the same. Because the fuel is still being ignited and burned like it should it runs the same, or hotter because of the leaner AFR's.

JCW lower compression?? I just read the info on the car, and i didn't see anything about lower compression, just stronger pistons. A great thing for a car that is meant to be driven more at the track. Since when is 21psi bad? The stock Pistons are a Malhe forged piston, and they will hold quite a bit of power.

Your right, it does have to be with it being small, but you said 21psi is too much, and Adam responded with its only 20psi at lower RPM as the boost tapers to redline, hence less boost than 20psi. You should read a little more careful before posting because you think we don't know what we are talking about.

You are correct, that curve is just like the stock motor. Lean to rich. When we tune the Unichip we find that the same curve works very well. The leaner mixutres make more TQ at lower RPM and don't cause knock. If we tuned in a flat AFR curve, power is lost, Torque is lost, and detonation is still NOT there and EGT's are not much cooler. LEaner is how this car runs. But there is a point where it doens't like to be lean and knock does happen. Also if the car has over boost problems and it goes to 8-10psi of boost (something we found before we had the Unchip) it would run perfectly happy at 14.5 AFR all the way to redline.

I have seen runs like that on stock R56's. I bet on those areas where the AFR went really lean, the boost dropped. If it did and the power dropped there, it could be from the intake temps going up from a scoop not being removed, or potentially from a Inlet hose collapsing. If this customer has one of our parts, i would like them to email us to make sure we get that taken care of.

Normally so do we, but there is no good solution for the R56 yet. Keyword is yet. We used the Unichip as a great stepping stone to satisfy peoples needs to for engine management. This also allows us to learn how the R56 response to fueling, timing boost, and other things, so we will be better prepared for future tuning solutions.

You can put the probe before the cat? There are lots of places to put the probe. All of which effect the AFR readings. The tail pipe is just fine, but this makes the readings much leaner than they are. Then add the fact there are 2 cats before that sensor its going to be way different. The only way to know what this offset is, is to test what it is before the cats and compare it to the tail pipe. So while that is true, those AFR numbers do not scare me.

We did install a lot of those, and now that the Unichip harness issues are gone, there must be an explanation.

When tuning different kinds of cars, people have to know they all tune differently. One car may only like to run at lean as 10.5 AFRS and then another would be perfectly fine with 12.0AFR's. Different engine designs require different methods. So since you are an R53 guy you are used to seeing a similar leaner to richer AFR curve. The same thing applies on those engines. If you came from the Subaru world, you would be cringing at how lean the SC engine runs at low RPM and high load. But that AFR is where they make the most TQ.

To give people an idea how well/safe DI works, during some of our testing of different boost control systems, we have done runs where the AFR stayed at 14.5 all the way to redline with only a slight loss in power, and ZERO knock. I say zero knock because when the ECU hears knock, or gets close to its threshold, you can see it pull timing on the dyno. This was even on our turbo kitted car making well over 220WHP.

 

I am not just saying it does....... it DOES have these effects. That is what i was trying to explain. I could spend hours stating the facts about how and why it works, and then even more hours about my personal thoughts about how it can be used for the better of man kind..... Until that time machine is invented, i just don't have the time.

Same here, i am providing information about things, not bashing your thoughts. So please don't think that.

 

I'm not concerned about the car running lean at lower RPM's, I'm concerned with the random lean spikes up to 14.5 around 5-6k

 

Regarding lower compression on the JCW Cars...

Engine modifications have been made to the air filter, air mass meter, exhaust system and catalyst. Air supply to the modified larger turbocharger is increased through fitment of a larger air intake pipe, which in turn creates a quicker induction phase. Also come with reinforced, specially polished pistons, as well as a strengthened cylinder head for optimised stability and a modified cylinder gasket. The intake valves and valve seat rings have also been upgraded with stronger and more resistant materials. This reduces the engine’s compression ratio. The new Sports exhaust system is instantly recognisable through the large polished stainless steel twin tailpipes. Modification of the exhaust system has also helped to reduce counter-pressure at the point of exhaust gas recirculation. Ducts in the exhaust manifold and turbocharger are split between two cylinders each. Congestion is therefore minimised when air is inducted to the turbocharger and “turbo lag” is virtually eliminated.

So, in effect MINI felt the need to lower the compression, strengthen almost EVERY part of the engine, and still only run 18 psi of peak boost (On a larger, more efficient turbo).

^-- Concerning...

 

alright now get back to making stuff that makes my mini faster.

 

PERFECT!

 

YES!!!! Enough of this horse play.

Someone start doing some real component design to save me the fabrication cost. Anyone care for my wish list?

 

Thank you Nick!

They didn't just "feel the need" to lower the compression and strengthen the internals...they came to that conclusion through extensive testing with the increased boost levels and a couple blown head gaskets.

They are engineers...and believe it or not, I think they just might be on to something with what they have developed for the JCW car.

 

I tried to explain that those spikes are from the car not running correct. I bet that the boost at those "spikes" also dropped from 16-ish PSI to 8-9psi. STill not good though. I agree, that under normal conditions, and boost staying consistent that is bad. But this is not the case, and like i explained, if the car sees too much boost, or too much MAF flow, it cuts boost way back, and at 5-10PSI the car just runs that lean.

Stronger is good! But its not like the stock engines are falling apart. Our shop car is a great example of big HP and engine still running great. With that said, no where have i found what the CR is. And that is the only place that mentions it. Just because valve seats, and valves are better that doesn't mean the compression drops. So if you read that sentence by itself it makes the author seem as though they are not understanding what they did. Also as i search around, people have copied that same basic info and mixed it up and even 4 different places write about the "Supercharger blades are set in optimum motion". But either way the lower compression is just fine, and i think it will allow for more power. BUt its not like 10.5CR is holding back power currently. That would be a better argument as to why Mini changed it. Whats holding back power is the turbo.

With that said does that mean the thousands of 10.3-1 CR audi's and VW are all going to blow up because thier ratio is too high. Again another direct injected motor that tons and tons of guys making 350+WHP.

I am sorry you feel this is horse play. I think its just educating people on how things work. I hope that none of our posts seem like we are arguing. I just feel its important to answers peoples questions or comments.

On your second comment, are you saying ALTA's parts just don't cut it, and you feel you need to fab something better? If so we would like to get feedback how to fill your needs. Or (which which would make more sense) are you talking "Electronic" component design, which i feel the same about, as we do not do that here. If its ECU reflashing, then our second solution is a little ways away. When its out, you will be very happy.

I love the fact the engine is built better. Just means we can push way beyond 300WHP with out worrying quite as much. And when this car is out, you better believe we will be the first with it, the first to tune it and the first to make big power.

Trust me, i am all about stronger things, and i hope you don't think i was arguing for the higher compression, i was explaining why its very different on a Direct injected car.

 

Perhaps something was wrong with the car and some kind of boost drop caused those AF's. I don't know. I'm sure the owner will deal with it. No doubt he's read this by now.

As far as the stock Prince motor falling apart. You guys probably have what, 10k miles on it? Any motor that's falling apart at that milage has some serious issues. Like I said, issues are going to take time to manifest themselves if they do at all.

On the lower compression, this is the quote from the Official MINI Press Release, I'd venture to say they PROBABLY know what they're talking about...

"The MINI John Cooper Works and MINI John Cooper Works Clubman are driven by a true power package based on the current engine of the MINI Cooper S, extensively revised for the MINI John Cooper Works CHALLENGE racing vehicle and now back on the road with refreshed power. Even the basic design of the 1,598 cc 4-cylinder engine has details which are drawn from motor racing. The cylinder block and bearing housing are made of aluminum, the four valves per cylinder are controlled by two upper camshafts, friction-optimised cam followers and hydraulic valve clearance compensation elements. The outlet valves are filled with sodium so as to meet the increased cooling needs of a turbo engine. The camshafts of the 4-cylinder are composite. Instead of using the conventional die-cast procedure, the cam rings are made of high-strength steel and shrink-fitted to the actual shaft. The intake camshaft has a continuously variable phase adjustment function by means of which the valve control times can be adapted to the relevant performance requirements.

The engines for the MINI John Cooper Works and the MINI John Cooper Works Clubman are made at the BMW Group engine plant Hams Hall (Great Britain) where the engine units for all MINI model variations are manufactured. In the case of the top-of-the-range engine, there are a number of special modifications to the production process to do justice to the increased output and the resulting higher temperatures in the combustion chamber, thereby guaranteeing maximum reliability of the drive system. The engines are fitted with reinforced and specifically ground pistons as well as a cylinder head with optimised rigidity and modified gasketing. The intake valves and valve seat rings are also made of especially resilient material, and as compared to the engine of the MINI Cooper S there is a slight reduction of the compression."

The drop in compression is likely due to redesigning the head, and the gasket selection. I believe the mentioning after valves was just sentence poor structure.

Source: Motoringfile

Eh, and I highly doubt the turbo was holding MINI USA back from squeezing out a measly 190-195 whp. A bigger downpipe and another 2-3 PSI of boost could have done that. They added a new turbo for the same reason they added a cylinder head to the last JCW package, because it helps them justify the *** raping.

Uh... The Audi guys aren't running 21 psi of boost to make that 350 whp, they're running 15-16, and that's with a bigger, more efficient turbo (Cooler temps). The tuners also have years of experience fiddling with the the motors, and even more time with the 1.8T, and I guarantee you they're not running 14+ AF's (More like mid to high 10's). It's also won several awards for it's durability (As has the 1.8t). The Prince is brand new, we know nothing about it at this point.

 

enjoying this thread very much.

 

Please do not be misled by my comment, but this is getting ridiculous, I do not see any point in responding to repeated negative commentary.

The first few times were great, informative, and needed explanation. I understand that not everyone has the same background, nor understands alot of basic design principles. I too post replies and try to help guide as well as help educate.

Secondly, I have many Alta parts, you guys make some great stuff. Right now I am very happy with my current setup. However there is a need for other hardware to go further. I gotta agree with the Mini engineers. in order to maintain reliability she need to be stronger.

I could be much happier though. I would love to increase the size of the turbo. To do that though, because I am an engineer, I need to fix some other things first. Currently the components I would love to add do not exist. I eluded to this a while ago. Here is my short list:

Forged internals,
Perhaps a little head work... larger valves, ported and polished would help. perhaps there is a better all around head design?
Is the exhaust manifold really ideal? at the very least SiN coated exhaust and turbo parts, or perhaps a good heatwrap for the turbo.
drive train -- transmission, quaif, stronger CVs and half shafts, clutch and pressure plate could be stronger.
These engines run a tad hot, if I make her run harder do I need increased cooling capacity?
You guys already make a water injection kit... I need to add that eventually.
What about a decent air intake, a nice scoop and grill, If the M7 is already there I have yet to see any photos, or drawings.

Electronics, well I bought the UniChip and am awaiting flux, as well as some hotter mapping, and of course once the parts are there, I need the ECU tune to make it all work right. A little tighter control of the engine would be very nice as well, she seems a little skittish at times.

 

Nicely put and you and I are thinking down the same lines

 

i need to hit the lottery. so i can do all that stuff too .