Johnny Posted April 9, 2008 Report Share Posted April 9, 2008 Does anyone know how much N/A power you get with a Danielson cam? Quote Link to comment Share on other sites More sharing options...
Bean Posted April 10, 2008 Report Share Posted April 10, 2008 Can you elaborate what you mean by N/A HP? Here NA means normally aspirated - IE no forced air systems. Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 10, 2008 Author Report Share Posted April 10, 2008 That's exactly what I mean. The stock engine, according to the factory specifications develops 180 hp with 0.8 bar boost. The N/A hp is 180 divided by the pressure ratio (PR), IE 180/1.8 = 100 hp. The more N/A hp you got, the less boost you need for a specific hp figure. Quote Link to comment Share on other sites More sharing options...
Bean Posted April 10, 2008 Report Share Posted April 10, 2008 That's exactly what I mean. The stock engine, according to the factory specifications develops 180 hp with 0.8 bar boost. The N/A hp is 180 divided by the pressure ratio (PR), IE 180/1.8 = 100 hp. The more N/A hp you got, the less boost you need for a specific hp figure. Weird - I've never heard of this reference, or the comparison used like this. The formula doesn't sound like it'd be accurate at all... Or is it just a for comparison sake? Is there a better explanation as to why or how it's done like this as it makes no sense to me as is. Also seems odd since it would be futile to know how much HP a turbo engine made normally aspirated. I also think it's not very complet to assume that with increased NA power you need less boost to acheive a given HP output. Turbo motors have to be built and tuned as a turbo motor. To me - it would be much more accurate to dyno a stock motor, change only the cam, and then redyno it for gains the cam gave. Turbo cams have very little overlap, so without boost - any NA numbers are pointless since the cams are designed for boost. I'm sure I'm missing something - or maybe that's just a term or figure used in Europe - I've just never heard of it, and don't fully understant why you'd use it... Rabin Quote Link to comment Share on other sites More sharing options...
V-M Posted April 11, 2008 Report Share Posted April 11, 2008 Agree with Bean. Dani cam have more lift and degrees -> better breating in high revs (means in N9T case over 4000). :-P V-M Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 11, 2008 Author Report Share Posted April 11, 2008 Cam choice is more than just turbo cams and n/a cams. You can use a n/a cam in a turbocharged engine, if you adapt the choice of turbo/exhaust manifold to it. It's a matter of pressure balance. Why don't you agree that with more n/a hp you need less boost? Where do you think the gains comes from when using a dani cam? It's useful to know N/A hp, because then you could calculate how much boost you'll need to reach your target. This in turn helps to choose turbo. It's obvious that a dyno session would be more accurate, but this gives a good indication. I have to say that I have no practical experience, but these terms and theories is widely used on Swedish forums, and the people that advocate this have pretty awesome engines. Quote Link to comment Share on other sites More sharing options...
V-M Posted April 11, 2008 Report Share Posted April 11, 2008 There is several aspects on that issue. If you take N/A car and put turbo cam on that you get ~20-25% less power. If you take turbo car and put N/A cam you get ~10-15% more power. Calculating these could be nice hobby but reality is different. Like I did try 318deg (0 lift) and 8.2mm lift cam on my grey beast and that was laugh... it bearly moved and hardly runned. In N/A engine that should give ~50hp more with related mods. So it totally depends on cam and engine. N/A cam on turbo engine is like having 290 deg cam on N/A car. IMHO V-M Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 12, 2008 Author Report Share Posted April 12, 2008 What backpressure and boost did you have? Quote Link to comment Share on other sites More sharing options...
Bean Posted April 12, 2008 Report Share Posted April 12, 2008 Turbo cams are TOTALLY different than a wild NA cam in that you want as little overlap as possible with a turbo cam since it's being pressure fed the intake charge. Modified NA motors usually run wilder cams with substantial overlap to help scavenge the burnt charge out while filling with new charge - so comparing the two really are apples and oranges. You simply can't turbo an NA engine and have it better than a properly built turbo engine. So many things are different between an NA motor and a force fed motor that any comparison between the two isn't going to be helpful at all... Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 12, 2008 Author Report Share Posted April 12, 2008 As I said before, it's a matter of pressure balance. The balance between backpressure and boost. The problem with fitting a N/A cam in a turbo engine is that the turbo was matched to have boost at lower revs (smaller turbine=more backpressure). When you take a cam with alot of overlap and backpressure greater than boost the cylinders don't get scavenged as good as they should and the engine runs like crap (low VE). What people do here where I live is that they use a "wild" N/A cam and combine it with a large turbo (=boost always higher than backpressure). The result is an engine that runs hard without boost, and when the boost comes, it says thanks you and give you a horsekick in the back. Of course this method of building engines has it's limitations and gives a certain character to the engine. It would be more optimal to have a cam with a little less overlap so less A/F mixture goes straight into the exhaust, but it works good for low-budget projects. Quote Link to comment Share on other sites More sharing options...
V-M Posted April 13, 2008 Report Share Posted April 13, 2008 In that I'm not agreeing Bean... there is no big difference on N9T engine cams and N/A Chrysler cams those u can see on those listings. As I sayed it depends on engine how big difference there is. V-M Quote Link to comment Share on other sites More sharing options...
Bean Posted April 13, 2008 Report Share Posted April 13, 2008 As I said before, it's a matter of pressure balance. The balance between backpressure and boost. The problem with fitting a N/A cam in a turbo engine is that the turbo was matched to have boost at lower revs (smaller turbine=more backpressure). When you take a cam with alot of overlap and backpressure greater than boost the cylinders don't get scavenged as good as they should and the engine runs like crap (low VE). What people do here where I live is that they use a "wild" N/A cam and combine it with a large turbo (=boost always higher than backpressure). The result is an engine that runs hard without boost, and when the boost comes, it says thanks you and give you a horsekick in the back. Of course this method of building engines has it's limitations and gives a certain character to the engine. It would be more optimal to have a cam with a little less overlap so less A/F mixture goes straight into the exhaust, but it works good for low-budget projects. Sorry - I've never heard of tuners optimizing an engine with this balance of boost and backpressure... Doesn't make sense to me as explained.... Just so we're clear though - What is your definition of backpressure? What I know is that Turbo engines use little overlap because there's no need for it due to boost... With overlap you'll get a lot of the raw air/fuel past the combustion chamber and into the turbo itself - and uncontrolled that'd be bad since it would ignite in the turbo (Basically uncontrolled anti-lag!). There's no need for any sort of scavenging as the old charge is literally blown out... I can see the attraction of having a stronger engine off boost - but running on boost wouldn't be very good from what I know... To me it makes more sense to size the turbo for your design goals, and then optimise the cam for your power delivery. A higher lift cam with little to no increase in overlap will likely be ideal - but I know that I would not want a wild NA cam with lots of overlap in it. Now just because I've never heard of it being done successfully doesn't mean it can't be done - it just goes against what I know up to this point... So if you have any info that backs up this kind of build I'd love to see/read about it. V-M - Correct - Stock turbo engines and stock NA engines usually do have very similar cams, since production engines have to be quite tame with good emissions and such. But I was refering to the comparison of a wilder NA cam with lots of overlap - not a stock one. I wasn't clear above so I fixed it. We're probably getting away from the original post though - and I still stand by my stance that comparing NA HP of a cam on a turbo engine isn't valuable info... Heck - even just testing it would be a hassle since you'd have to remove the turbo and tune it as an NA motor - and it would still be crap because of the low compression. Are you sure this comparison isn't used for guys putting turbo's on NA cars? I can see this argument being used if you're doing a junk yard turbo on a NA car... But it goes out the window if you're trying to make it work for a stock turbo engine. This could also just be a moot argument since our definitions of these words could just be different... Rabin Quote Link to comment Share on other sites More sharing options...
Bean Posted April 13, 2008 Report Share Posted April 13, 2008 OK - found this article on the supra site you linked for Agnes... turbo tech article At the end of the article they start describing what you're talking about, so I understand what you're talking about with reference to backpressure of the actual turbo itself. I knew this existed - but it's never been a consideration since there are other areas I feel are more critical. Once they are addressed - backbpressure is already optimized as well as it can be automatically. The article did back me up by stating that Turbo engines need less overlap than NA motors - but there was no mention of what happens when running wilder overlapping cams on a turbo motor. So if you have any links to articles where they've run wilder NA cams with more overlap and a turbo it would be an interesting read... Rabin Quote Link to comment Share on other sites More sharing options...
V-M Posted April 13, 2008 Report Share Posted April 13, 2008 Yes now we are talking same language True N/A wild cams are totally non functional in turbo engine. I know several BMW 325 N/A which have put directly turbo without opening engine and those are hell a beasts and those are not junk jard cars (model year 2000 ->). I don't get that back pressure? Is it measured from exhaust? V-M Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 13, 2008 Author Report Share Posted April 13, 2008 Backpressure is the pressure in the exhaust manifold, before the turbo. It's usually measured in the collector. Rabin, If you read what I wrote, you'll see that I do agree with you that less overlap is optimal. What I mean is that it would be better (for low-budget riding) to use a wilder N/A cam combined with a large turbo, instead of using a tamer cam with a smaller turbo and crank the boost up to insane levels (which will be needed to get to you hp goal) since this would ruin the pressure balance. It's easy to see the benefit of less boost. If you have higher backpressure than boost, exhaust gasses will be forced to enter the cylinder again and mix with the fresh charge. Power will also be lost due to the piston needs to force the exhaust gasses out of the cylinder, using power from the crank. You found an article that describes pretty much everything I've said very well. It seems like the only thing we disagree with is weather or not using a wild N/A cam in a turbo engine works good and if more N/A hp means that you can use less boost to get to a certain hp goal. I wish I had an article in english that I could show you, but everything I've read myself to is in Swedish. V-M, Good thing that you mentioned those BMW's. They are 2.5L and have 192 hp, for comparison this would mean around 165hp in our 2.155L engine. To compare with the 100 hp stock. They work good for turbocharging, and I'm guessing that the cams they use have more overlap than a regular turbo cam. BTW, do you still have that 318 deg cam? Quote Link to comment Share on other sites More sharing options...
V-M Posted April 13, 2008 Report Share Posted April 13, 2008 V-M, Good thing that you mentioned those BMW's. They are 2.5L and have 192 hp, for comparison this would mean around 165hp in our 2.155L engine. To compare with the 100 hp stock. They work good for turbocharging, and I'm guessing that the cams they use have more overlap than a regular turbo cam. BTW, do you still have that 318 deg cam? That comparison does not open to me? For me it's like comparing planes and cows As I sayed no engine openings done = std cam is in use. Of cause not, they re-grinded it to dani spec cam. V-M Quote Link to comment Share on other sites More sharing options...
Bean Posted April 14, 2008 Report Share Posted April 14, 2008 You found an article that describes pretty much everything I've said very well. It seems like the only thing we disagree with is weather or not using a wild N/A cam in a turbo engine works good and if more N/A hp means that you can use less boost to get to a certain hp goal. I wish I had an article in english that I could show you, but everything I've read myself to is in Swedish. Yep - we're agreeing on everything except the wild NA cam and turbocharging. I just don't think it'll work as well as using a stock NA cam, or better yet a wilder TURBO cam that has higher lift and still optimised with little overlap... I'm also not sure about the attention to the backpressure...Still think it will fall into place after you select the right cam and the right turbo.... Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 14, 2008 Author Report Share Posted April 14, 2008 That comparison does not open to me? For me it's like comparing planes and cows As I sayed no engine openings done = std cam is in use. Of cause not, they re-grinded it to dani spec cam. V-M They have much more hp/L and max power is at 6000 rpm, I made the assumption that the cams they use are wilder than the stock cam used in the N9T and that they have more overlap. Yet they still work good when turbocharging. Was that cam made from scratch or was it a regrind? Yep - we're agreeing on everything except the wild NA cam and turbocharging. I just don't think it'll work as well as using a stock NA cam, or better yet a wilder TURBO cam that has higher lift and still optimised with little overlap... I'm also not sure about the attention to the backpressure...Still think it will fall into place after you select the right cam and the right turbo.... Rabin I'm sure it falls into place for some who know what they're doing, but if you don't measure, you'll never know... Quote Link to comment Share on other sites More sharing options...
V-M Posted April 14, 2008 Report Share Posted April 14, 2008 Was that cam made from scratch or was it a regrind? What u mean? There is no raw cams available on N9T engine. Danielson have them but I have not get answer if they would like to sell them. So every cam is re grinded. And 8.2mm is max lift from cam what can be gained. Surely if do some welding there is possible to have more lift. But eaven with that 8.2 is on valve 10.7mm which is giving good flow. About that lobe, there is big differences in different engines how they are defined and built using that lobe degrees. So it's not direct at N/A engines are using big lobe (106-116) and turbos have small (100- 108). V-M Quote Link to comment Share on other sites More sharing options...
Bean Posted April 14, 2008 Report Share Posted April 14, 2008 They have much more hp/L and max power is at 6000 rpm, I made the assumption that the cams they use are wilder than the stock cam used in the N9T and that they have more overlap. Yet they still work good when turbocharging. Production NA motors don't have a lot of overlap, and the stock cams do usually work well with turbo's. (Most just need to drop compression) BMW owners that had their NA engines tricked out with big Schrick cams, and high compression pistons always swap out the cams for stock units if they decide to then go turbo... It's possible to do low boost high compression engines with good engine management - and that does give you the feeling of a strong motor off boost - then the horse kick when the turbo comes in... But turbo'ing that same motor with the wild Schrick cams wouldn't work due to the excessive overlap... This last scenario is the one I've never seen anyone do - and it just doesn't make sense to me that it would work if someone did do it. (At least not better than the same motor with the stock NA cams in it.) Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 14, 2008 Author Report Share Posted April 14, 2008 What u mean? There is no raw cams available on N9T engine. Danielson have them but I have not get answer if they would like to sell them. So every cam is re grinded. And 8.2mm is max lift from cam what can be gained. Surely if do some welding there is possible to have more lift. But eaven with that 8.2 is on valve 10.7mm which is giving good flow. About that lobe, there is big differences in different engines how they are defined and built using that lobe degrees. So it's not direct at N/A engines are using big lobe (106-116) and turbos have small (100- 108). V-M I ment just that, if it was made from a raw cam or if it was a regrind. Is it possible to get another cam regrinded to those specs? I might be interested in one of those. What is the rocker ratio? 1.30? I don't understand why you talk about lobe separation, since it hasn't been mentioned earlier in the thread. Production NA motors don't have a lot of overlap, and the stock cams do usually work well with turbo's. (Most just need to drop compression) BMW owners that had their NA engines tricked out with big Schrick cams, and high compression pistons always swap out the cams for stock units if they decide to then go turbo... It's possible to do low boost high compression engines with good engine management - and that does give you the feeling of a strong motor off boost - then the horse kick when the turbo comes in... But turbo'ing that same motor with the wild Schrick cams wouldn't work due to the excessive overlap... This last scenario is the one I've never seen anyone do - and it just doesn't make sense to me that it would work if someone did do it. (At least not better than the same motor with the stock NA cams in it.) Rabin Then how do you explain this? http://02mannen.wastegate.se/ It's a BMW 2002 with a M10 engine with a Dr. Schrick 304 cam and KKK K27 turbo, boost is 1.3 bar. And this: http://savarturbo.se/?sida=content/bilarna.php&bil=peter A BMW 1602 with a M10 engine, 304/10mm (Schrick 304?) cam with "Enough power to spin the tires on all gears". I'm sorry it's in swedish, but you should be able to figure out something in the engine specs. Edit: Here are some videos on the last car (different paint job). http://media.savarturbo.se/peter/halkigt.mpg http://media.savarturbo.se/peter/med_shift-cut.mpg http://media.savarturbo.se/peter/utan-shift-cut.mpg Quote Link to comment Share on other sites More sharing options...
V-M Posted April 15, 2008 Report Share Posted April 15, 2008 I ment just that, if it was made from a raw cam or if it was a regrind. Is it possible to get another cam regrinded to those specs? I might be interested in one of those. What is the rocker ratio? 1.30? I don't understand why you talk about lobe separation, since it hasn't been mentioned earlier in the thread. Then how do you explain this? Surely specs for that cam are available in grinder, I have one but I have to check if person who ordered it will still buy it (I did ordered it 2 years ago and it have been in my carage shelf since). I don't remember was it 1.3 or 1.4... Well it's time to talk then. Cause thats the point in that difference. 304 deg (well I didn't find how that was measured) there is big difference if thats is 0 lift or 0.05" lift degrees. Sure you can make that work but driveability is surely poor but hi rev power can be nice... as can be seen. Remember these are just my opinions and experience on engine building. V-M Quote Link to comment Share on other sites More sharing options...
Bean Posted April 15, 2008 Report Share Posted April 15, 2008 Then how do you explain this? http://02mannen.wastegate.se/ It's a BMW 2002 with a M10 engine with a Dr. Schrick 304 cam and KKK K27 turbo, boost is 1.3 bar. And this: http://savarturbo.se/?sida=content/bilarna.php&bil=peter A BMW 1602 with a M10 engine, 304/10mm (Schrick 304?) cam with "Enough power to spin the tires on all gears". I'm sorry it's in swedish, but you should be able to figure out something in the engine specs. Nope - don't have to explain it. There's not enough info to go on. Sure it works and that's awesome, but I couldn't find any specs on overlap, or how the duration was measured. Also have no comparison on other motors running properly engineered turbo cams... All I could find was that the 304 was the first cam to start being advertised as being wild... Still a decent street cam though - and there were 2-3 wilder cams on top of that one... So it might work - but if we go back to your original question - you're comparing turboing and NA engine, and the techniques they use and trying to make it work - to a factory turbo engine and the techniques that are used to tune them... And that's where I think your logic is faulty... Apples and oranges. Granted - I don't have the language skills to decifer the sites you provided - but I stand by questioning the logic of determining NA hp a cam gives a factory turbo motor. Rabin Quote Link to comment Share on other sites More sharing options...
Johnny Posted April 16, 2008 Author Report Share Posted April 16, 2008 Surely specs for that cam are available in grinder, I have one but I have to check if person who ordered it will still buy it (I did ordered it 2 years ago and it have been in my carage shelf since). I don't remember was it 1.3 or 1.4... Well it's time to talk then. Cause thats the point in that difference. 304 deg (well I didn't find how that was measured) there is big difference if thats is 0 lift or 0.05" lift degrees. Sure you can make that work but driveability is surely poor but hi rev power can be nice... as can be seen. Remember these are just my opinions and experience on engine building. V-M Ok, it would be great if you could check that! I'm pretty sure it's measured at 0 lift. As you might know I have no real experience in engine building yet, so I spend my time reading. Nope - don't have to explain it. There's not enough info to go on. Sure it works and that's awesome, but I couldn't find any specs on overlap, or how the duration was measured. Also have no comparison on other motors running properly engineered turbo cams... All I could find was that the 304 was the first cam to start being advertised as being wild... Still a decent street cam though - and there were 2-3 wilder cams on top of that one... So it might work - but if we go back to your original question - you're comparing turboing and NA engine, and the techniques they use and trying to make it work - to a factory turbo engine and the techniques that are used to tune them... And that's where I think your logic is faulty... Apples and oranges. Granted - I don't have the language skills to decifer the sites you provided - but I stand by questioning the logic of determining NA hp a cam gives a factory turbo motor. Rabin I never said that you have to use the wildest cam available, this was the only material I found that you might get anything out of. Enough said about that, I think I have showed you that it's possible to use a wilder N/A cam in a turbo engine with good results. But why is it so hard to understand that with a stronger N/A engine, you need less boost? I think it's pretty simple to see that for example engine 1 with 170 N/A hp would need less boost than engine 2 with 100 N/A hp to get to 200 hp. I'll explain how I'm thinking, we start from the top with the ideal gas law, we have PV = nRT where: P is the absolute pressure of the gas (=boost + atmospheric pressure) V is the volume of the gas n is the number of moles of gas (=molecules of gas) R is the universal gas constant (nevermind about this one) T is the absolute temperature If we rearrange this law a little, we get n = PV/(RT). Of course, the gas is air in our case. As you can see, that the molecules of air will be determined by the volume, pressure and temperature. When pressure or volume increase, the molecules of air increase. When temperature increases, the number of molecules decrease. And vice versa. The actual volume of air inside our cylinder that can be combusted will be VE x Cylinder displacement (at a given rpm), the pressure will be boost + atmospheric. The temperature of the air will be dependent on the compressor efficiency and the intercoolers ability to cool the air. The first engine in the example needs 17% more air molecules in the cylinders to get to 200hp. The second engine needs 100% more air molecules to get to 200hp. The way we choose to do it is to increase the pressure. If we raise the pressure to 17% over atmospheric on the first engine then we get exactly 17% more air molecules into the cylinders, and 17% more power (with correct A/R ratio). And if we increase the pressure 100% on the second engine on the second engine, we get 200hp. As you can see, VE has great influence on the amount of air molecules, and VE is affected by the turbo and cam you choose. With wilder cam, the choice of turbo becomes more important since the pressure balance will affect VE more and vice versa. The "formula" I wrote earlier is not exact in any way, it is in fact just a way to get a rough estimate on how much boost you need. You will probably need more if you start with a N/A engine since compressors only work with ~60-76% efficiency, some fresh charge may get wasted in the exhaust manifold etc. etc. But if you take an engine with turbo already, the factor of compressor efficiency should not matter so much, only the difference in efficiency between the different places in the turbo map. Haha, this became alot more detailed than I though when I started to write, I hope I made it understandable. It may or may not be correct, but it's my way of thinking about this. Quote Link to comment Share on other sites More sharing options...
Bean Posted April 16, 2008 Report Share Posted April 16, 2008 Holy crap Johnny - you got too much time on your hands! You are comparing apples and oranges... And I don't see the point. NA motors are different than turbo motors and they both get tuned differently. Period. I totally see your point about needing less boost on a stronger motor - but this is only valid up to a certain point. There's a reason why turbo engines have lower compression, and less overlap... They can take far more boost - and in the end will make more power than the "stronger" NA motor with boost. (And by NA I mean high compression motors that never had a turbo, and which still retained the stock bottom end.) Maybe we need to define our terms first to avoid miscommunication. Even your examples you provided show that they had built turbo motors out of NA ones by using lower compression pistons - they weren't true NA motors anymore! Maybe this is a language thing... Rabin Quote Link to comment Share on other sites More sharing options...
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