346whp @ 0 pounds of boost
11-23-2010, 04:24 PM
#1
346whp @ 0 pounds of boost
That's right! 346whp is a number a supercharger or a turbocharger could put down and it wouldn't be half bad.
Put in larger cams in preparation for our big cam test. These JWT C9/C10 cams require head clearancing, valve cover clearancing and lots of checking to be sure these *huge* cams won't be hitting things. Now that we are confident everything is clearing and running correctly, hopefully we won't have to spend 30+ hours on the next cam swap! (Like we did with this one).
Gains of 8whp over the other cams were found, the C10 on the exhaust would likely make even more power, and will be part of our next test.
Of interest to some of you tech dudes, the duration of the cam with the pistons we're using did not allow us to use the full travel of the intake sprocket. So to be safe, Clark from JWT advised a mechanical stop was required to prevent bending all of the valves (or worse!). This is what I came up with today before loading the car on the dyno. It allows for approximately 27 degrees of intake travel:
Here is the graph, we might have an iphone video coming soon which doesn't even come close to doing the sound justice - but is still better than nothing.
EDIT:
Engine Part List:
Stock non Revup DE heads - JWT C10 Intake, C9 exhaust w/ JWT valve springs
JE Custom 12:1 pistons, Eagle Rods, Revup Oil Pump
SGM Longtube headers + 3.5" Race exhaust
Stock revup lower plenum
SGM custom upper intake with 90mm throttle body
Tilton clutch + flywheel
Unorthadox crank pulley
Motec M800 ECU
Put in larger cams in preparation for our big cam test. These JWT C9/C10 cams require head clearancing, valve cover clearancing and lots of checking to be sure these *huge* cams won't be hitting things. Now that we are confident everything is clearing and running correctly, hopefully we won't have to spend 30+ hours on the next cam swap! (Like we did with this one).
Gains of 8whp over the other cams were found, the C10 on the exhaust would likely make even more power, and will be part of our next test.
Of interest to some of you tech dudes, the duration of the cam with the pistons we're using did not allow us to use the full travel of the intake sprocket. So to be safe, Clark from JWT advised a mechanical stop was required to prevent bending all of the valves (or worse!). This is what I came up with today before loading the car on the dyno. It allows for approximately 27 degrees of intake travel:
Here is the graph, we might have an iphone video coming soon which doesn't even come close to doing the sound justice - but is still better than nothing.
EDIT:
Engine Part List:
Stock non Revup DE heads - JWT C10 Intake, C9 exhaust w/ JWT valve springs
JE Custom 12:1 pistons, Eagle Rods, Revup Oil Pump
SGM Longtube headers + 3.5" Race exhaust
Stock revup lower plenum
SGM custom upper intake with 90mm throttle body
Tilton clutch + flywheel
Unorthadox crank pulley
Motec M800 ECU
Last edited by SGSash; 12-16-2010 at 06:36 AM.
11-23-2010, 05:00 PM
#3
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do you have the specs for the C10's? cant seem to find them. Sasha, can you explain what the purpose is of lowering the exhaust duration in comparison to the intake duration. I am seeing that some have larger intake durations than exhaust and some have the exact same amount and I am not sure what this does.
For example, Jim wolf C9 has 283.5* in 283.5* ex, Kelford's 189-B has 282* in 272* ex
I love watching the progress you guys are doing, keep up the good work!
For example, Jim wolf C9 has 283.5* in 283.5* ex, Kelford's 189-B has 282* in 272* ex
I love watching the progress you guys are doing, keep up the good work!
Last edited by lemmiwinkz; 11-23-2010 at 05:03 PM.
11-23-2010, 05:40 PM
#6
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are those 2 runs on the same set up?
or is the dotted line from a previous set up?
looks like you had to sacrifice a bit of low end power for high end
but damn 346...
or is the dotted line from a previous set up?
looks like you had to sacrifice a bit of low end power for high end
but damn 346...
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11-23-2010, 08:02 PM
#10
From other cars that have been on both our dynapack and a dynojet, our dynapack is usually a few percent lower. I would venture a guess that we would be close to 360 on a dynojet.
The loss in midrange torque I am guessing is coming about because we aren't able to further advance the intake cam. If I had pistons with larger intake valve reliefs that torque would pick right back up.
The target power band for this engine is 5750 to 8250 rpm anyways!
Regarding the exhaust cam sizing differences, I am no expert, but we are just experimenting here. We will also be testing the C10 on both the intake and exhaust, but my hunch is there won't be much gain. The intake is the restriction In the system right now more than the exhaust, so I feel like more cam on the intake was of the greatest benefit. My thinking could be totally off however.
I also think we are starting to reach the chocking point of the stock heads, so I am hoping some porting will yeild further gains, but that will be a project to tackle in a few months time.
The loss in midrange torque I am guessing is coming about because we aren't able to further advance the intake cam. If I had pistons with larger intake valve reliefs that torque would pick right back up.
The target power band for this engine is 5750 to 8250 rpm anyways!
Regarding the exhaust cam sizing differences, I am no expert, but we are just experimenting here. We will also be testing the C10 on both the intake and exhaust, but my hunch is there won't be much gain. The intake is the restriction In the system right now more than the exhaust, so I feel like more cam on the intake was of the greatest benefit. My thinking could be totally off however.
I also think we are starting to reach the chocking point of the stock heads, so I am hoping some porting will yeild further gains, but that will be a project to tackle in a few months time.
11-24-2010, 04:56 AM
#12
It's not much but, here's the iphone video my friend took. It sounds 10,000 times better in real life of course.
http://www.youtube.com/watch?v=Z3-Pe...layer_embedded
http://www.youtube.com/watch?v=Z3-Pe...layer_embedded
11-24-2010, 09:24 AM
#17
As you guys get closer and closer to crazy durations will you guys be trying something like the Fontana Nissan guys? I would imagine the the advancing & declination get less and less useful around the 302 mark (due to the operating rev range).
From Fontana Nissan's Website
Also a cool bit from Nissan's Nismo site showing the change in cam phasing's affect on power through different rev ranges. I thought it really helped to explain your explaination of why you dropped heavily in the mid range, especially note the 3000-4000 range.
From Fontana Nissan's Website
Also a cool bit from Nissan's Nismo site showing the change in cam phasing's affect on power through different rev ranges. I thought it really helped to explain your explaination of why you dropped heavily in the mid range, especially note the 3000-4000 range.
11-24-2010, 11:38 AM
#19
Regarding torque/horsepower:
Torque and horsepower have a defined relationship. If you know either torque or horsepower, and you know RPM, you will know the other variable.
To get more horsepower, you need either more torque, or more rpm.
Torque is basically maxed out by the displacement of the engine. The relationship between torque and engine displacement is basically describing the engines efficiency. Brake Mean Effective Pressure (BMEP) lets us compare engines of different displacement:
To put the VQ in perspective for you, my engine with the non-revup lower plenum was making close to 290 lb-ft of torque at 3.5 liters:
The formula for BMEP is simple, and it gives us somewhat of an idea of the potential torque we should be able to expect out of a certain displacement, when comparing it to racecar engines of similar breed:
BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)
So, taking 290 lb-ft of torque and 213.5 cubic inches we get: 204.83 (the unit is PSI). Now that is to the wheels. If we want to just be conservitive and assume another 10% at the engine: 319 lb-ft the BMEP is 225PSI
Now to compare to race engines:
Formula 1: ~220PSI
Nascar Cup: ~219PSI
Corvette Z06: ~165PSI (advertised numbers)
Porsche 911 GT3: ~206PSI
Looking at the BMEP by itself, it looks like we have the most amazing engine in the world! And it shows that it's making a HUGE amount of torque compared to most race tuned naturally aspirated engines.
Now that I've made the VQ look like a better engine than formula one, I must continue to explain the details:
We're missing a big chunk of the picture. It's much easier to make greater torque at LOWER rpm, than it is to make that same torque at higher RPM. This is because the faster you spin the engine, the more losses you rack up with friction (bearings, cams smashing valves, pistons on cylinder walls etc) and pumping losses (that's why pulling a vacuum in the crankcase frees up power at high rpm).
The reason the BMEP is lower on the F1 and Nascar cup engines, is because they have tuned the engines to spin at high RPM, and the goal is to make the torque (and horsepower) as high as possible at those higher RPMs. That means sacrificing low and mid-range torque to make the engine efficient in those areas. The tuning comes in all sorts of different forms, like header design, cam sizing and timing, intake runner diameter and lengths, etc.
So naturally the peak torque falls, and the BMEP goes down with it. Since the engine keeps making torque at higher RPM, the horsepower goes up (a very significant amount). Using sequential gearboxes with close gears, you can keep the engine operating at high RPM and the loss of low-end torque no longer matters since you're never there!
Is it funny what I described is EXACTLY what modern auto manufactures are doing with their 7 and 8 speed automatics to make up for their high revving engines with fairly small powerbands? (Think of how low the torque is on the new G37/370z 3.7's, but how high the horsepower is). Honda has been doing it forever of course, except with VTEC they can keep a ton of low end power compared to what it would be like if it was always on the big cam.
Back on topic - to make horsepower, REAL horsepower (like 100whp per liter), you NEED to sacrifice torque (or have variable everything). That's why you will see my racecar build going up in power and down in peak torque (or at least staying the same). The peak torque used to be higher than it is now, despite the fact that it's making 15 more horsepower. Because we've used an intake manifold and cam that sacrifices sub 5000rpm torque for more torque (and as a result MORE horsepower) at 6000rpm+
So to summarize:
290 lb-ft of torque at 5000rpm is no where near as good as 230 lb-ft of torque at 7000rpm. The graph to display that relationship, is called horsepower.
(290lb-ft of torque @ 5000rpm = 276hp)
(230lb-ft of torque @ 7000rpm = 306hp)
This post really got out of hand. Sorry!
Torque and horsepower have a defined relationship. If you know either torque or horsepower, and you know RPM, you will know the other variable.
To get more horsepower, you need either more torque, or more rpm.
Torque is basically maxed out by the displacement of the engine. The relationship between torque and engine displacement is basically describing the engines efficiency. Brake Mean Effective Pressure (BMEP) lets us compare engines of different displacement:
To put the VQ in perspective for you, my engine with the non-revup lower plenum was making close to 290 lb-ft of torque at 3.5 liters:
The formula for BMEP is simple, and it gives us somewhat of an idea of the potential torque we should be able to expect out of a certain displacement, when comparing it to racecar engines of similar breed:
BMEP = 150.8 x TORQUE (lb-ft) / DISPLACEMENT (ci)
So, taking 290 lb-ft of torque and 213.5 cubic inches we get: 204.83 (the unit is PSI). Now that is to the wheels. If we want to just be conservitive and assume another 10% at the engine: 319 lb-ft the BMEP is 225PSI
Now to compare to race engines:
Formula 1: ~220PSI
Nascar Cup: ~219PSI
Corvette Z06: ~165PSI (advertised numbers)
Porsche 911 GT3: ~206PSI
Looking at the BMEP by itself, it looks like we have the most amazing engine in the world! And it shows that it's making a HUGE amount of torque compared to most race tuned naturally aspirated engines.
Now that I've made the VQ look like a better engine than formula one, I must continue to explain the details:
We're missing a big chunk of the picture. It's much easier to make greater torque at LOWER rpm, than it is to make that same torque at higher RPM. This is because the faster you spin the engine, the more losses you rack up with friction (bearings, cams smashing valves, pistons on cylinder walls etc) and pumping losses (that's why pulling a vacuum in the crankcase frees up power at high rpm).
The reason the BMEP is lower on the F1 and Nascar cup engines, is because they have tuned the engines to spin at high RPM, and the goal is to make the torque (and horsepower) as high as possible at those higher RPMs. That means sacrificing low and mid-range torque to make the engine efficient in those areas. The tuning comes in all sorts of different forms, like header design, cam sizing and timing, intake runner diameter and lengths, etc.
So naturally the peak torque falls, and the BMEP goes down with it. Since the engine keeps making torque at higher RPM, the horsepower goes up (a very significant amount). Using sequential gearboxes with close gears, you can keep the engine operating at high RPM and the loss of low-end torque no longer matters since you're never there!
Is it funny what I described is EXACTLY what modern auto manufactures are doing with their 7 and 8 speed automatics to make up for their high revving engines with fairly small powerbands? (Think of how low the torque is on the new G37/370z 3.7's, but how high the horsepower is). Honda has been doing it forever of course, except with VTEC they can keep a ton of low end power compared to what it would be like if it was always on the big cam.
Back on topic - to make horsepower, REAL horsepower (like 100whp per liter), you NEED to sacrifice torque (or have variable everything). That's why you will see my racecar build going up in power and down in peak torque (or at least staying the same). The peak torque used to be higher than it is now, despite the fact that it's making 15 more horsepower. Because we've used an intake manifold and cam that sacrifices sub 5000rpm torque for more torque (and as a result MORE horsepower) at 6000rpm+
So to summarize:
290 lb-ft of torque at 5000rpm is no where near as good as 230 lb-ft of torque at 7000rpm. The graph to display that relationship, is called horsepower.
(290lb-ft of torque @ 5000rpm = 276hp)
(230lb-ft of torque @ 7000rpm = 306hp)
This post really got out of hand. Sorry!
11-24-2010, 12:42 PM
#20
Thanks for the break down on this relationship, I've seen the generic explaination many times and for the most part understood it, but this helps in clarifying the relationship even further. But it also brought up a separate thought. I noticed you said in a previous thread you would consider bringing the Rev-up collector in to play when you tried some of the top-ended cams, was this run done with it?