Don't have a copy of that. Is it worth getting? If so, could you please list some info on it.
Advanced Engine Theory and Design
- Thread starter Alky V6
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Thanks Nearing. With the lack of feedback or participation, sometimes I have to wonder if anyone is getting anything out of this. I hope this is causing some wheels to turn so that your own projects can benefit. I would love to start seeing some new and different projects that might, in some small way, have been inspired by this thread.
I am in the process of building a StageII motor and have followed this thread with much interest. I think I speak for many other lurkers when I say that this thread has been a very instructional and useful resource.
My build is somewhat unconventional (odd-fire 274 ci, dry sump, SII max ported heads, twin 60-1, 2-sets of 75lb injectors staged, Electromotive TEC3r EMs w/ coil on plug ignition, etc, etc - stick shift - built for road race/occasional drag & street use in a Datsun 280Z) and I really appreciate discussions based on real science rather than repetitive formulas for setups that have worked for others.
I say, "Stay the course" and when I get my junk running - should be in the next few months if the machine shop ever gets done - I hope to contribute.
Your using a TEC3r. I'm using the same system. That's great. I finally have someone I can compare notes with. I understand you need to run a cam sensor to be able to run the coil on plug deal? Or are you doing it a different way? I've eliminated my cam sensor, but I guess I could always fab one back in.I am in the process of building a StageII motor and have followed this thread with much interest. I think I speak for many other lurkers when I say that this thread has been a very instructional and useful resource.
My build is somewhat unconventional (odd-fire 274 ci, dry sump, SII max ported heads, twin 60-1, 2-sets of 75lb injectors staged, Electromotive TEC3r EMs w/ coil on plug ignition, etc, etc - stick shift - built for road race/occasional drag & street use in a Datsun 280Z) and I really appreciate discussions based on real science rather than repetitive formulas for setups that have worked for others.
I say, "Stay the course" and when I get my junk running - should be in the next few months if the machine shop ever gets done - I hope to contribute.
Back on subject. Camshafts. I plugged in a smaller duration cam to do a comparison against my current cam specs and would like to pass on the results.
My current specs:
Duration @ .050
Int. 252
Exh. 260
Lobe lift .420
Lift with 1.7 ratio rocker .714
Lobe separation 110
Intake centerline installed at 5 degrees advance.
Sample specs:
Duration @ .050
Int. 232
Exh. 240
Lobe lift .380
Lift with 1.7 ratio rocker .646
Lobe separation 114
Intake centerline installed at 1 degree advance.
With the smaller cam there is a loss in HP from 22 @ 5000 rpm to 73 @ 7200 rpm.
With the smaller cam there is an increase of 14 HP @ 3500 rpm that increases to 100 @ 4750 rpm.
The increase at 4750 rpm is related to a quicker turbo spool up. Once both are at full boost, the larger cam wins out and the benefit increases as rpm rises. At 6500 rpm both HP curves have peaked and the smaller cam starts to slowly drop off immediately. With the larger cam, the HP line stays flat until 7200 rpm and starts to slowly drop after that.
If I was worried about turbo spool up time, the smaller cam would look very attractive.
This test included tuned intake and exhaust systems, tuned to the larger cam. Don't know how this same test would have turned out with untuned manifolding.
My current specs:
Duration @ .050
Int. 252
Exh. 260
Lobe lift .420
Lift with 1.7 ratio rocker .714
Lobe separation 110
Intake centerline installed at 5 degrees advance.
Sample specs:
Duration @ .050
Int. 232
Exh. 240
Lobe lift .380
Lift with 1.7 ratio rocker .646
Lobe separation 114
Intake centerline installed at 1 degree advance.
With the smaller cam there is a loss in HP from 22 @ 5000 rpm to 73 @ 7200 rpm.
With the smaller cam there is an increase of 14 HP @ 3500 rpm that increases to 100 @ 4750 rpm.
The increase at 4750 rpm is related to a quicker turbo spool up. Once both are at full boost, the larger cam wins out and the benefit increases as rpm rises. At 6500 rpm both HP curves have peaked and the smaller cam starts to slowly drop off immediately. With the larger cam, the HP line stays flat until 7200 rpm and starts to slowly drop after that.
If I was worried about turbo spool up time, the smaller cam would look very attractive.
This test included tuned intake and exhaust systems, tuned to the larger cam. Don't know how this same test would have turned out with untuned manifolding.
good info I would be intrested on a comparison of a stage headed engine with a race cam and the same engine with a street grind say in the 230 range @.50. I was told that it would give up 100 HP over the race grind. My combo is 270" stage 2 heads ported, 6.5 rods,9:1 cr, The intake is a conleys sheet metal with a 90mm TB and a 230/230 cam to start with I also have a 248/248 @.050. I went with the smaller cam to get the engine dialed in and have a good lower end. Plus it would be easy on the valve train.
I plan to run 47/80 turbo.
I plan to run 47/80 turbo.
experiment
I have been following your thread like many others. I am in the process of building my stage 2 , stage 2 headed motor. I never got into the "quantum physics" of the motor. I have had blinders on up until I started reading your articles. I was going to throw stage 2 heads on a 274 cu in. block a big turbo or two and go fast. Simple. I never considered air velocity, port sizes,etc.. I wanted to use my Edelbrock tunnel ram because it looks cool not because of it's function. I purchased used twin turbo headers hoping that I can create a "y" pipe for a big single turbo. I would like to contribute this to the discussion. I noticed that John Kaase (builder of Behemoth cubic inch motor 900+ cu in. Ford motors) uses a spacer between the head and block to add cubic inches. I spoke to a contractor of his and he said that I should use and aluminum block create a 1 inch spacer and sleeve the block with the space on the block and basically request $$$$$ everything be made an inch longer. I think in theory it would work very well. Do you think that this idea is realistic of 300+ cu inch Buick V6's. I am sure that the custom part list wouldn't be unobtainable. Ron PS I got my thinking cap on now!!:biggrin:
I have been following your thread like many others. I am in the process of building my stage 2 , stage 2 headed motor. I never got into the "quantum physics" of the motor. I have had blinders on up until I started reading your articles. I was going to throw stage 2 heads on a 274 cu in. block a big turbo or two and go fast. Simple. I never considered air velocity, port sizes,etc.. I wanted to use my Edelbrock tunnel ram because it looks cool not because of it's function. I purchased used twin turbo headers hoping that I can create a "y" pipe for a big single turbo. I would like to contribute this to the discussion. I noticed that John Kaase (builder of Behemoth cubic inch motor 900+ cu in. Ford motors) uses a spacer between the head and block to add cubic inches. I spoke to a contractor of his and he said that I should use and aluminum block create a 1 inch spacer and sleeve the block with the space on the block and basically request $$$$$ everything be made an inch longer. I think in theory it would work very well. Do you think that this idea is realistic of 300+ cu inch Buick V6's. I am sure that the custom part list wouldn't be unobtainable. Ron PS I got my thinking cap on now!!:biggrin:
I've seen the spacer trick used on Honda blocks. It does work. But to use it on a Buick V6 won't work. To make use of the spacer you would need to increase the crankshaft stroke. Camshaft clearance is at the minimum as it is with the strokes that are commonly used now. Good thinking though.I have been following your thread like many others. I am in the process of building my stage 2 , stage 2 headed motor. I never got into the "quantum physics" of the motor. I have had blinders on up until I started reading your articles. I was going to throw stage 2 heads on a 274 cu in. block a big turbo or two and go fast. Simple. I never considered air velocity, port sizes,etc.. I wanted to use my Edelbrock tunnel ram because it looks cool not because of it's function. I purchased used twin turbo headers hoping that I can create a "y" pipe for a big single turbo. I would like to contribute this to the discussion. I noticed that John Kaase (builder of Behemoth cubic inch motor 900+ cu in. Ford motors) uses a spacer between the head and block to add cubic inches. I spoke to a contractor of his and he said that I should use and aluminum block create a 1 inch spacer and sleeve the block with the space on the block and basically request $$$$$ everything be made an inch longer. I think in theory it would work very well. Do you think that this idea is realistic of 300+ cu inch Buick V6's. I am sure that the custom part list wouldn't be unobtainable. Ron PS I got my thinking cap on now!!:biggrin:
I once had a copy of Bill Jenkins' book and lost it. Could you post some info on it so I can look around for a copy.
Don,
Sure no problem just as soon as I get back home I'll get you all the info. Good book.
Marty
This sounds like an interesting comparison. I'll work on it tomorrow.good info I would be intrested on a comparison of a stage headed engine with a race cam and the same engine with a street grind say in the 230 range @.50. I was told that it would give up 100 HP over the race grind. My combo is 270" stage 2 heads ported, 6.5 rods,9:1 cr, The intake is a conleys sheet metal with a 90mm TB and a 230/230 cam to start with I also have a 248/248 @.050. I went with the smaller cam to get the engine dialed in and have a good lower end. Plus it would be easy on the valve train.
I plan to run 47/80 turbo.
I just finished another comparison that turned out a way I would not have expected. I performed the previous comparison with a T91 instead of a T76. Same boost (26 psi) and intercooler. A/R ratio was larger. 1.00 versus .96. The result was a little surprising. Horsepower differences were about the same at the top end. Max boost was reached by a later rpm. The amazing thing was that the turbo spooled much quicker with the big cam. 800 rpm sooner to full boost. The smaller cam had more HP at the mid range, but had a harder time getting the big turbo to spool up. I've been trying to figure out if there is a good reason for this. Keep in mind that this is just a simulation.
Another note. At the higher boost levels (30+), large cam and my engine config, the T91 has it all over the T76. Much more efficient, and the simulation shows no surging at midrange. It appears the T91 has a very broad efficiency island. I know the compressor map shows this, but I'm very surprised that the engine simulator shows the same thing. I want one. When I plug in a T80 or T88, I get surge.
Your using a TEC3r. I'm using the same system. That's great. I finally have someone I can compare notes with. I understand you need to run a cam sensor to be able to run the coil on plug deal? Or are you doing it a different way? I've eliminated my cam sensor, but I guess I could always fab one back in.
Correct. You need a cam sensor to do COP. I still need to investigate whether the E-motive will work with an optical cam sensor - if not I will mod the Buick unit with a custom trigger wheel and an aluminum cap containing a magnetic pickup. Documenting that setup can be my first contribution:biggrin: .
Looking forward to it. Thanks.Correct. You need a cam sensor to do COP. I still need to investigate whether the E-motive will work with an optical cam sensor - if not I will mod the Buick unit with a custom trigger wheel and an aluminum cap containing a magnetic pickup. Documenting that setup can be my first contribution:biggrin: .
Appreciate it, Marty. Thanks.Don,
Sure no problem just as soon as I get back home I'll get you all the info. Good book.
Marty
I'm trying to understand the surge problem with the 80 and 88 in the demo you tried. Please explain what is surge. I though it was when the turbo is making boost but the throtle plate is only partially open....like during a light tip in at cruise speed say 45-55mph. But you engine is race only TB is either open 100% or closed 100% so why surge?
I'm trying to understand the surge problem with the 80 and 88 in the demo you tried. Please explain what is surge. I though it was when the turbo is making boost but the throtle plate is only partially open....like during a light tip in at cruise speed say 45-55mph. But you engine is race only TB is either open 100% or closed 100% so why surge?
If you're familiar with a turbocharger compressor map, you know that there is an airflow axis and an air pressure axis. Within the map is the compressor's efficiency island. Usually, close to the middle of this island is where the output of the compressor is most efficient. Heating the compressed air the least.
I have a much easier time internally visualizing how this works rather than trying to explain it, so forgive me if I confuse you more than make this clearer for you.
If you pick out a particular airflow and air pressure output for a compressor, you can go to this map and pinpoint an area on the compressor map and see how efficient the compressor is at that point. If the airflow demand is too high from a particular compressor, it ends up to the right of the efficiency island where efficiency drops and the compressed air output is heated to undesirable levels. Add to that too high of a pressure demand and you overspeed the compressor risking damage. That is located in the upper right hand region of the compressor map. Generally, you want to pick a turbocharger that will give you no less than 60% efficiency at maximum airflow of your engine setup while under boost.
To the left of the efficiency island is the surge zone. A dashed line separates the surge zone from the efficiency island. As an engine boosts up, the airflow and pressure can be mapped out by a line on the compressor map, starting in the lower left hand corner and angling upward and to the right through the efficiency island. At the point of full boost, that trace line stops moving upward and continues to travel to the right until maximum engine airflow is reached.
If you can match a turbocharger that will skate along the right side of the surge line while the engine is boosting up, you can end up in a higher efficiency zone at maximum engine airflow. Pick a turbocharger that is too small for your engine airflow requirement and the trace line moves upward to the right of the high efficiency region of the island and then moves to the right, well past the 60% efficiency zone. Pick a turbocharger that is too large and the trace line moves upward too close to the surge line and may cross that line to the left of it, causing compressor surge. This will occur as the turbo is boosting up or as the trace line is making its upward and to the right rise before full boost has been reached and the trace line has had a chance to move straight over to the right into a more efficient zone on the compressor map.
The size and shape of the efficiency island and the surge line is different for each compressor.
Some compressors are more tolerant to low airflow and high pressure than others. Those that are not will go into surge easier.
If I just brought up more questions or did not explain it well enough for you, let me know and I'll try again. It's really important that you understand this. It is a very important tuning point.
Surge is when the compressor goes into an unstable delivery of the airflow and pressure. It feels like you've taken your engine by the shoulders and are violently shaking it back and forth. Feels wicked.
I'll get to that comparison sim tomorrow night. Good night y'all.
Don
There is a discussion in the general thread about titanium vs forged rods and I was wondering what were your thoughts on using them in a Buick V-6. I asked in the Stage II forum a little while back and Dale Cherry has them in his low 8-second Stage II.
There is a discussion in the general thread about titanium vs forged rods and I was wondering what were your thoughts on using them in a Buick V-6. I asked in the Stage II forum a little while back and Dale Cherry has them in his low 8-second Stage II.
Don
There is a discussion in the general thread about titanium vs forged rods and I was wondering what were your thoughts on using them in a Buick V-6. I asked in the Stage II forum a little while back and Dale Cherry has them in his low 8-second Stage II.
I finally picked up my new cam from Crower yesterday. OOOHooHoo. There is nothing like the look of a brand new, wide nose, billet roller camshaft. I asked them about titanium versus steel, since I noticed the question on the BB. Crower is a manufacturer of titanium rods. In the area of strength, no difference. Weight, big difference. Price, big difference. I even specified maximum effort, turbocharged applications. If you have the money to burn, go with titanium. At the moment, it is very expensive and is hard for manufacturers to get ahold of. Someone in the market is buying up a lot of titanium causing the price to skyrocket and availability to be spotty. Is it China? Someone is building weapons. For one rod, your looking at $500.00 to $600.00.
Why is lighter better? Anytime you can lighten up the rotating and reciprocating assembly of the engine or any component of the drivetrain for that matter including driven accessories, the engine will rev faster and you will have less HP losses through the drivetrain. Just be careful. In most instances lighter will also mean weaker. Never sacrifice safety over weight.
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