Very good advice SY,it works for all of us. Thank you

 

Im interested how and when people began to believe that 1.1-1.2 is max for pump gas....

Properly mapped...you can run more.

 

Tony would you please explain to me how internal engine pressures are relative to BAR. How is 1.0 Bar on GT40's compared to 1.0 BAR on K16's. I am not sure I understand the theory. Not setting you up, just a novice at this and wanting to learn.

Peas,
Ryan

 

Tony,

I would NEVER - NEVER doubt your tuning prowess. The basic problem here is that NONE OF US are remotely as good as you are. Having said that, we jump in, get on the gas, and we run these cars in far from ideal conditions; most of the time with far from ideal fuel to boot... This is 98% of members, in a most likely scenario. I know that with YOU tuning the car, dropping it off regularly, zero leaks, regularly serviced diverter valves, recalibrated ECU for weather and etc. that you could consistently pull more out of these cars than even GOD could. The problem is that we don't have the ability to run those numbers (1.25+BAR) without issues given all of the other (almost limitless) variables that come into play at that state of tune.

I used to deadlift almost 600 pounds, for example. Could rep out with 485 all day long. The 585 pound number almost killed me. The state of tune required to hit another 15 pounds (to hit 600) was just not going to happen with any reliability due to the external constraints. (my passion for good beer and some decent ****tails perhaps?) I'm just being realistic on what SHOULD be run as a regular programming setup vs what is POSSIBLE to run with your continuous expertise. @ almost 575WHP/575WTQ there's almost no one in the room who can "track" that much power, and certainly not without laying rubber everywhere. The danger level is stratospheric (for the average street racer/weekend track guy) vs the additional joy received. MEOJ < MROFU (marginal experience of joy ...is less than... marginal risk of f**king up). Saves engines, keeps "more fun under the curve" if you know what I mean.

Best Regards,

SY

 

Well, I have a 91 octane file on my K16 hybrid car and I have seen 1.3 bar and spike to 1.4 on 91 octane fuel. No issues at all and I have done way more than 50 runs with no cels, no problems at all. So, when I hear people say that it cannot be done, I wondered but was told that it is not a problem.

 

Not to step on Tony's toes. But a larger turbo will in most cases not create as much heat due to the increased turbo effeciency. A smaller turbo is working harder to acheive said boost, which increases IATs(even post intercooler in some cases) therefore increasing pre-ignition(higher internal pressures). Outside of that, I can't imagine the differences are that much. When I switched from K03s on my S4 to K04s, I gained timing at the exact same boost due to effeciency. Tony can fill us in even more on the other factors.

 

you move a LOT MORE air per unit of BAR with larger turbos. 1-BAR with G35's vs 1-BAR with K16's is no comparison. 1.3-BAR on G16's is totally maxxing them out. You'll soon need new turbos.

get a set of GT28's with REAL ball-bearing cartridges and they'll spool SUPERFAST and feel like K-16's with tons more punch.

you won't necessarily get the 7000RPM power out of them that you'd get with larger compressors but then you'd have a virtually ZERO lag situation while filling up the 5500-6500RPM space in the powerband with extra horsepower and interestingly, the 3500-5000RPM space with extra torque vs a distinct dropoff (in torque) @ 3500-4000RPM's which is the limiting factor with the K16's. the higher torque @ 4K-RPM's and above will materially aid your freeway marauding adventures in the 140-170mph area.

overboosting K16's does only one thing.... delivers VERY HOT air to the motor. you should not do this if you want the car to live. get larger turbos and some IC's if you want to get more aggressive. you're slowly COOKING your intake system and it's going to kill the motor, ultimately.

 

Tony just finished indicating how people are so set into pressures and here we go making statements to the contrary. Not all K16's are the same. I would venture a guess that gt28's have nothing on these K16 hybrids.

 

I think you have a good point, but I would like to further elaborate on your statement. I think the thing to focus on is not the boost pressure(as Tony said), and focus on the quality of boost (density,temps, etc.) This is where you get into compressor effeciency graphs to figure out what area you can effeciently run a turbo. I live in Denver and many people here think that what is good at sea level is good here. The fact is that when you are pushing turbo effeciency outside or to the edge of its capability, the results are minimal. My S4(sorry for the Audi content) with K03s would actually run faster at 15 psi than 17 psi. Not all boost is equal.

 

My point is people talk about boost being the absolute factor for engine demise. Detonation kills these engines. Boost levels can play a factor in the cause of detonation, however so can heat, too much or incorrect ignition advance, low octane fuel or bad fuel, etc.

It just as easy to tune a car to 1.4 bar on pump as as it is to 1.1 bar on pump gas. As long as you take into account all factors of the tune, you will be fine running both boost levels.

 

I don't understand the physics of this...

How much air you move is quantized by the combustion chamber- you only move so many cc's per cycle. pressure in, pressure out, volume - times RPM - is flow rate.

1.3bar is 1.3bar, given the same combustion chamber and same back pressure, it is the same.

I'm not talking overall dynamic performance, or if a larger turbo will generate the same 1.3bar with less back pressure....just how there are differences in flow rate with the same pressure given different turbos generating the same pressure.

So what do I have wrong?

 

very true, UMW does not tune for boost, the tune is timing, afr, octane etc. The boost is what it is and the tune limits boost, as my understanding goes. I know very little about that tune, but I am sure the tuners can throw their 2 cents in about this.

 

what you say makes more sense. Given the same cam timing specs(lift/duration), turbos at 1.3 bar should be close, I thought the issue was that stock turbos have trouble getting there. I also think when talking turbos, it is really the compressors we're talking about here. That is where the flow comes from. The only issue I see that can cause the smaller turbo to flow less at the same bar is heat, since heat expands the mixture and you do have a smaller charge going into the cylinders, I would guess, but again conjecture on my part.

That is why I'd like to hear more from tuners/engine builders/etc on this and how this really works in our cars.

 

Agreed. Temperature will alter the air density, and hence more air mass. (grams/second)

But technically speaking, flow is flow. (cc/second)

 

what I have tried to throw out there are some basics given all of the blather thrown around as to which turbos are better and etc...

clearly, a set of HIGHLY MODIFIED K-16's will outperform a "standard" version of something else in many cases. the point is not that you can continuously modify or hollow out or bore out K16's and get them to flow more air or that continuously larger compressor wheels won't ultimately creat more flow. this is obvious to most people. the problem is when people don't begin with the basics. tony has a GREAT set of 16G's with programming that you can kill with. on balance, though, you want to own a larger pair of compressors vs simply swapping to larger compressor wheels and hollowing the turbos out to flow more air.

the 16G is probably the least expensive upgrade possible with the best results for all-around street performance. I would stand by the statement, though, the the 24/18G's are going to make more power, and that vs a "run of the mill" 16G your GT28's are ALSO going to produce more power on top as a middle of the road solution. your 24/18G solution is for people who want 700+ horsepower; you can keep the boost down and use them for daily driving or you can add a LOT of fuel and hit the dragstrip with these. they're crushingly powerful with the right additional INTERNAL components and have true engine-breaking potential without a careful setup. (see RPM North!) the idea here is not to see how much power a Honda CIVIC will make on nitrous. It's still a Honda at the end of the day. in general, you go bigger, you get more power. you run a tight tune with the SAME absolute PSI numbers and with larger compressors vs highly modded small compressors, the physics are all there. you get more (denser) cool air and a motor that is likely to make more power and live longer vs overboosting what are STILL smaller compressor bodies.

SY