tyoneal

James,

Thank you so much for you help you have no idea how much I appreciate it.

Did you port the intake to match the gaskets? Yes
I'm tying to get an idea for how the D1 is pulley'd. I'm not sure that's a large enough supercharger for that much cubes and unfortunately my software doesn't have ProChargers in it to choose from. I've got a Vortec V1-T trim though and they are similar enough and I should be able to figure it out.
I need a reference for the boost and RPM. Ideally something lower than where the graphs start to fall off. For example, what is the boost pressure at exactly 4500RPM and wide open throttle?
In the model I've got open right now very tiny changes in pulley sizes (drive ratio) are making huge differences in power. I'm starting the think the blower could be choking it instead of force feeding it. Ironically, now that you mention this, when under WOT you feel the power up to a point with the blower whine, then at least to me, I get the feeling that it is trying to push more forced air into the intake than it can swallow.

The intake and the TB should be able to handle 1200+ cfm, and "Supposedly" the injectors are large enough for the application @ #65psi.

Also, do you happen to know which tuning package was used to tune it? I've got TunerCATS OBD-II and EFI-Live and could have a look if you've got it.

Info needed if you have it:
1. seat-to-seat numbers on GM #24502611 cam

Cam # 24502611
@ 0.050
ID 211
ED 230
LSA 112
ICL 108


IVO -2.5 BTDC (- indicates ATDC)
IVC 33.5 ABDC
EVO 51 BBDC
EVC -1 ATDC (- indicates BTDC)
ECL 116
Overlap -3.5

2. exact boost at 4500 RPM @ WOT (On it's way)
3. crank and supercharger pulley sizes (On it's way)

The Tuner is a "HP", if that makes sense.

Take a look at the intake manifold pressure in the lower graph, subtract 14.7 and that's the boost number I am trying to make match your setup.

What I don't have is any information down low in the RPM range.

When tuning I've noticed that most people go through all the "Gears" first then make the actual pull for the DYNO.

Is there any reason why a tuner couldn't pull down the tranny by putting the shifter into the low/first "Gear" in the 4L80e, then just run it to redline from idle?

Ratios of the 4L80e:

1 2 3 4 R
2.48 1.48 1.00 0.75 2.07

Differential Gear Ratio:
4.10:1

32 inch Tall Tires

Let me know if any of this helps, and I will continue gathering the information you want.

Thanks,

Ty O'Neal

James B.

iTrader: (1)

Moregrip, long time no chat!
Ty,
Dyno pulls need to be done when the transmission is in a 1:1 (or nearest possible) ratio for the most accurate feedback. Any gear reduction in the transmission would impose greater mechanical losses than 1:1 ratio. In most 3 and 4-speeds that 1:1 is going to be 3rd gear. Some tuners will even lock out a downshift and lock up the torque converter for that pull. If not going to that effort the pull cannot begin until vehicle speed exceeds the point that wide open throttle would invoke a downshift - that has to be avoided. As far as doing a pull locked in first or second, sure it's possible it's just not normal practice.
Back to the cam for a second, I've got those valve event numbers already but they are the @0.050" numbers. There's another set of numbers that specify the events from the moment opening begins to closing ends, and adding those into the simulator enhances accuracy by allowing the software to calculate ramp rates and better represent valve overlap. I haven't been able to locate seat-to-seat numbers for this or other GM BBC cams. It's like they don't bother to publish it ever.
Your injectors are rated at 65lbs/hr and that's probably @3-Bar (approx. 43.5 psi) fuel pressure. Your actual fuel pressure is likely the stock 4-Bar (approx 58 psi) which would mean the injectors flow more like 75# an hour and that would support over 850 force-inducted horsepower without even exceeding 80% duty cycle, so yeah the injectors are not the problem.
The reasons I'm asking for pulley sizes driving the blower are so that I can determine if the D-1SC is going to be large enough for the application. Boost potential is effectively limited by the impeller RPM limit. For that model it's 62,000 RPM and that's with an internal gearing of 4.10:1. We start with the fuel cut-off RPM programmed into your PCM and work backwards. The specs for that unit advertise supported horsepower to 925, so right off I'm thinking it's got too small of a pulley on it. Based on what pulley sizes you've got now and then seeing what boost level it's achieving at specific RPM and WOT we should be able to come up with a pulley sizing solution.
Would be neat to see some pics too.

James B.

iTrader: (1)

Here's another chart. This one has your exact heads modeled (I used the CNC-ported versions I already had on file for the last one) and I've changed the blower to a Vortech V7. After comparing the specs and power potentials of Procharger and Vortech the V7-YS is actually a closer match to the D-1SC than a V1 or V2 is. The D-1SC has impressive potential.

tyoneal

James:

Thanks again for the help with modeling the engine. I was going to mention that your values regarding the intake say "Tunnel Ram", actually I have Victor jr intake on it now.

I think part of my problem is I am in need of a dual plenum intake manifold so I can move the tq. and hp. back in the normal operating range of the engine/cam. After looking back at the first tune before adding the additional flow rate of the intake and the Fast TB (It had the original TB on it, which would crapped out at 640 cfm.) it was peaking about 3800 rpms then dropping off.

I am thinking a good dual plenum intake from edelbrock would be a good move. The one I want that works from Idle to 5500 "Performer", doesn't have the Bosses for the injector rails while the next higher intake 1500-6500 "Performer RPM" does, however, I think would not possibly take full advantage of the cam I have in the truck, which should pull like crazy right off idle.

Also one thing I was thinking about. If the engine with the cam that is in it, should make power from idle to 5500 then it seems to me I would want a larger blower that could provide 10 psi as early as possible in the rpm range as possible, then once it started to exceed the maximum amount of boost it was tuned for, a "bleeder" valve of some kind could maintain the SC boost at a constant 10 psi. instead of continuing to add more and more boost as the engine reached 5500 rpm's.

Is there such a thing? I cannot imagine that there isn't a way to do this.

If it could provide 10 psi at 2000 rpm's and carry it though 5500 rpm's, then rev limit to to 5800 or so, I believe I would not recognize my truck, nor the small on my face, not seen since my first kiss.

The tuner shows on the graph that the engine now does continue to make power up to around 6500, and I really don't want to spin the engine that quick. It says it will start floating the values once spun that fast. I want this engine to last another 200k if possible.

Another question:
You mentioned:

"Dyno pulls need to be done when the transmission is in a 1:1 (or nearest possible) ratio for the most accurate feedback. Any gear reduction in the transmission would impose greater mechanical losses than 1:1 ratio. In most 3 and 4-speeds that 1:1 is going to be 3rd gear."

Other than road friction and aerodynamic friction one would have on the street, why would locking first gear down and pulling just through it alone, so a lower estimation of low end power and tq could be documented?

Since you know the amount of the gear reduction of the transmission is known, and the rear gear, and height of the tires is known, it would seem like an accurate measurement of the power could be documented in the supposed "Useable" rpm range?

Is it Torque converter loss or something like that? The TC should lock up pretty quickly I would think it was especially made for 900 ft/pounds/tq, or am I just out in left field somewhere?

I have noticed that this engine runs about 40-60 degrees F* cooler than my other one did. I'm checking the milage to see if there has been any improvement there as well.

Thanks again for you help, I'll see what I can find out on the cam information you needed as well as the boost @ 4500 rpm.

BTW: His graph didn't even start measuring power until the engine was about 4600 rpm. Which as far as I'm concerned tells me nothing given how the truck will be used.

Thanks again,

Ty

tyoneal

James:

I forgot:

"I've got those valve event numbers already but they are the @0.050" numbers. There's another set of numbers that specify the events from the moment opening begins to closing ends, and adding those into the simulator enhances accuracy ..."

Are those the numbers usually measured @ 0.020 lift?

Thanks,

Ty

James B.

iTrader: (1)

The seat-to-seat specs are also called "advertised duration". Some cam manufactures advertise the numbers at 0.006". Comp does that. With both the advertised duration and the @.050" duration the simulations can calculate ramp rate and draw a nice curve.
This is the cam I run in my 502: EFI Hydraulic Roller Cam - Chevrolet Big Block Mark VI 454, 502 285/295 - Lunati Power
Back to the dyno, the PCMs in our trucks are not even programmed to lock the converter until third grear - first and second are locked out. The reason for wanting pulls with the converter locked is that it will throw all the numbers off if open. The dyno knows engine RPM, transmission gear ratio, rear end ratio, and tire diameter. It needs all of those parameters because its trying to calculate engine torque not tire torque. If the converters is unlocked you get an RPM delta between the flexplate and input shaft. The job of the converter is to convert that RPM difference into additional torque to the input shaft, but the process is not efficient which is why ATF heats up so quickly in high-stall speed scenarios. That torque conversion is why high-stall converters launch off the line so well - the input shaft could momentarily see double the torque the engine is actually producing. The amount of torque multiplication a converter supplies is proportional to the RPM delta it allows. Those factors taper off as turbine (input shaft) RPM increases.
The lower the transmission gear the more torque the rear end will receive. All gear systems, whether the transmission planetaries or the ring and pinion, will experience more parasitic losses as more torque is put through them. The load causes friction and friction converts mechanical energy into heat. In third gear no planetaries are turning inside the transmission - output shaft matches input shaft RPM. Another factor to consider with dynos is traction. The lower the gear the higher the torque multiplication to the rear end. The dyno has a limit to how much toque can be put down, so staying within torque and traction limits is accomplished by going faster in a higher gear.

Boost from a centrifugal.
What you're talking about as far as bleeding off boost exists, yes. It's a bypass and works sort of like the bypass valve on the exhaust side of a turbo and also like the blow-off valve on the compressor side of the turbo. It's different though.
1. The bypass typically connects between the output side and the input side of the supercharger in sort of a circulation configuration. Keep in mind that when bypassing it will be heating up the charge air more.
2. The bypass must not alter the metering of air going through a Mass Airflow Sensor. For example, the MAF must be upstream of bypass entry point back into the inlet stream, or it can be on the pressurized side downstream of the bypass valve.
3. The reference point (vacuum line) for the bypass valve needs to be just before the throttle body, after the intercooler.
4. The bypass valve can be after the intercooler just before the throttle body so that cooled charge air is being bypassed instead of hot air from the compressor, but MAF location needs to remain completely before or completely after that loop.
5. If you're running your MAF pressurized (look for information on how to re-enforce the body so the rivet tabs don't break) it becomes possible to vent the bypassed air to the engine bay instead of back to the compressor inlet. Just make sure the bypass valve is upstream from the MAF so air metering remains true.

Those heads do an awesome job of maintaining an even temperature transferring heat to the coolant. It's a characteristic of aluminum. 40 to 60 degrees sound like a hell of a lot though and raises question. There is an important difference in how Gen-V/VI BBCs are cooled versus the Mark 4. Earlier big block had series cooling - the water pump pushed chilled coolant into the front of the block, it flowed around the cylinders all the way to the back where it entered the head and then flowed forward through the head until going into the manifold in the front. The heater circuit served as a form of bypass but was unregulated. In the later blocks they switched to parallel cooling. In this setup the water enters the front of the block the same but instead of entirely having to go to the back of the block to get into the head the coolant passages between the head and deck between the cylinders are enlarged so that the temperature of the head can be more evenly maintained front to back. Maintaining even temperature is only possible with coolant in motion. The Vortec L29 intake manifold has a bypass in it with an important feature - it is controlled by the thermostat. If you look the thermostat for one of these motors it has a disc at the bottom. That disc lowers and closes off the coolant bypass back to the water pump as the engine reaches operating temperature. When that bypass is open the water pump maintains a high recirculation rate though the heads to keep the temps even throughout. When the bypass closes it just goes through the radiator but the point is that flow is maintained no matter what temp the coolant is at. So, all that being said, what is the coolant bypass configuration of the manifold you've got in there?

Back to that manifold for a second, all the dynamics of intake port geometry and velocity change with boost. Granted with a centrifugal it's a little more important in the lower RPM. The point of dual plane manifolds in the past was to try to even out the suction pulses through the multiple barrels of the carburetor. We don't care about that any more. You also don't have a cam with so much duration that you get reversion at low RPM. Stick with the EFI Victor Jr. - it's actually great for the application and I wish I had one.

tyoneal

[QUOTE=James B.;5317232]The seat-to-seat specs are also called "advertised duration". Some cam manufactures advertise the numbers at 0.006". Comp does that. With both the advertised duration and the @.050" duration the simulations can calculate ramp rate and draw a nice curve.

I have been looking for hours for this specific information and I have been unable to find the "Advertised Duration", of this particular cam. Iconically I haven't heard that way of calculating Duration in many years, prior to the now more common measurement of Duration @ .050. This is just something I haven't come across in a long time, my mistake. The measurement you listed from your message of "0.006", I am familiar with, the one I mentioned was a mistake based on my lack of current usage.

This is the cam I run in my 502: EFI Hydraulic Roller Cam - Chevrolet Big Block Mark VI 454, 502 285/295 - Lunati Power

This cam appears to be similar, but a bit "Hotter" than the one I have in my engine.

Back to the dyno, the PCMs in our trucks are not even programmed to lock the converter until third grear - first and second are locked out. The reason for wanting pulls with the converter locked is that it will throw all the numbers off if open. The dyno knows engine RPM, transmission gear ratio, rear end ratio, and tire diameter. It needs all of those parameters because its trying to calculate engine torque not tire torque. If the converters is unlocked you get an RPM delta between the flexplate and input shaft. The job of the converter is to convert that RPM difference into additional torque to the input shaft, but the process is not efficient which is why ATF heats up so quickly in high-stall speed scenarios. That torque conversion is why high-stall converters launch off the line so well - the input shaft could momentarily see double the torque the engine is actually producing. The amount of torque multiplication a converter supplies is proportional to the RPM delta it allows. Those factors taper off as turbine (input shaft) RPM increases.
The lower the transmission gear the more torque the rear end will receive. All gear systems, whether the transmission planetaries or the ring and pinion, will experience more parasitic losses as more torque is put through them. The load causes friction and friction converts mechanical energy into heat. In third gear no planetaries are turning inside the transmission - output shaft matches input shaft RPM. Another factor to consider with dynos is traction. The lower the gear the higher the torque multiplication to the rear end. The dyno has a limit to how much toque can be put down, so staying within torque and traction limits is accomplished by going faster in a higher gear.

I appreciate your thorough explanation regarding the Dyno's that measure from the rear wheels, it was very insightful. I am guessing what I would desire can only be accomplished by removing the engine from the truck and putting the engine in a "Engine Only" Dyno, where the only measurement recorded is that from the crankshaft itself.

So a tuner locks up the Torque converter, and lock's the transmission in it's 1:1 gearing, so a more accurate measurement could be measured, Right?

Does this mean getting performance numbers off idle are not possible? I really would like to see the down low performance.

I was reading that if I used the:

PERFORMER RPM™ (1500 - 6500 RPM)
A dual-plane, high-rise designed with a 180° firing order greatly produces incredible top-end horsepower while retaining great throttle response. Their larger plenums and runners match high-lift cams, free flowing exhausts and other modifications of a high-output engine. Great for street or strip.

or

RPM AIR-GAP (1500 - 6500 RPM)
Offering a wide selection of multiple carburetor manifolds, or dual-quad designs. The all-new RPM Air-Gap dual-quads are the latest design, featuring an open air space that separates the runners from the hot engine oil for a cooler, denser charge for more power.

would best about the best I could find in a dual plane for my truck. I'm sure I would lose power over 5500 rpm's or so due to Valve float, however if I changed the springs out and put some in that had an additional; 50# - 75# Seat weight, the engine would spin safely to the 6500 peak.

What are you thoughts on this?

I really wish someone made a idle to 5500 dual plane, oval port intake with the fuel rail bosses in them so my EFI could be set up properly. The Down low Torque is really what I need in my truck.

Boost from a centrifugal.
What you're talking about as far as bleeding off boost exists, yes. It's a bypass and works sort of like the bypass valve on the exhaust side of a turbo and also like the blow-off valve on the compressor side of the turbo. It's different though.
1. The bypass typically connects between the output side and the input side of the supercharger in sort of a circulation configuration. Keep in mind that when bypassing it will be heating up the charge air more.
2. The bypass must not alter the metering of air going through a Mass Airflow Sensor. For example, the MAF must be upstream of bypass entry point back into the inlet stream, or it can be on the pressurized side downstream of the bypass valve.
3. The reference point (vacuum line) for the bypass valve needs to be just before the throttle body, after the intercooler.
4. The bypass valve can be after the intercooler just before the throttle body so that cooled charge air is being bypassed instead of hot air from the compressor, but MAF location needs to remain completely before or completely after that loop.
5. If you're running your MAF pressurized (look for information on how to re-enforce the body so the rivet tabs don't break) it becomes possible to vent the bypassed air to the engine bay instead of back to the compressor inlet. Just make sure the bypass valve is upstream from the MAF so air metering remains true.

Continued on the next page.

tyoneal

Post continued:

Those heads (The Brodix Race Rite's?) do an awesome job of maintaining an even temperature transferring heat to the coolant. It's a characteristic of aluminum. 40 to 60 degrees sound like a hell of a lot though and raises question. There is an important difference in how Gen-V/VI BBCs are cooled versus the Mark 4. Earlier big block had series cooling - the water pump pushed chilled coolant into the front of the block, it flowed around the cylinders all the way to the back where it entered the head and then flowed forward through the head until going into the manifold in the front. The heater circuit served as a form of bypass but was unregulated. In the later blocks they switched to parallel cooling. In this setup the water enters the front of the block the same but instead of entirely having to go to the back of the block to get into the head the coolant passages between the head and deck between the cylinders are enlarged so that the temperature of the head can be more evenly maintained front to back. Maintaining even temperature is only possible with coolant in motion. The Vortec L29 intake manifold has a bypass in it with an important feature - it is controlled by the thermostat. If you look the thermostat for one of these motors it has a disc at the bottom. That disc lowers and closes off the coolant bypass back to the water pump as the engine reaches operating temperature. When that bypass is open the water pump maintains a high recirculation rate though the heads to keep the temps even throughout. When the bypass closes it just goes through the radiator but the point is that flow is maintained no matter what temp the coolant is at. So, all that being said, what is the coolant bypass configuration of the manifold you've got in there?

This is a good question, I'm wondering if I have a thermostat in the cooling system at all. Usual operating temp was about 210F* - 220 F* I was able to get the temp to about 205 F* today after running the a/c and running slowly in town. I may just have a faulty thermostat, in the engine or there might be one of a lower temperature operating range. I seriously have barely put 50 miles or so on the engine as of now so it is still in need of some breaking in and fluid change.

It is strange, upon startup the engine has a type of rattle to it. It was this was when I first got the truck as well. Do you have any idea what that is?

Back to that manifold for a second, all the dynamics of intake port geometry and velocity change with boost. Granted with a centrifugal it's a little more important in the lower RPM. The point of dual plane manifolds in the past was to try to even out the suction pulses through the multiple barrels of the carburetor. We don't care about that any more. You also don't have a cam with so much duration that you get reversion at low RPM. Stick with the EFI Victor Jr. - it's actually great for the application and I wish I had one.[/QUOTE]

When I take off from a light it feels like there is poor air velocity, it slowly picks up to about 4800 then really goes. The problem with that is to get into the band I have to run very fast actually to fast for any speed limit in the area.

What intake are you running now? Would I not be better off with one of the dual plane intakes and a very quick boost configuration in the engine? What are your thoughts about the slightly heavier valve springs? I have always felt like I was on the edge on 6000 RPM's in a BBC.

I'm going to speak with a shop here locally that come really highly rated and see what their thoughts are about this. If I move to a dual plane I'll have a Victor Jr for sale, Hint, Hint!

What size tires are you running, and does your gear splitter, split 1st gear in half, or split between 1st and 2nd gear?

Another thing if I understand you correctly the gauges and such are running off the transmission and basically outside of the ECM/PCM of the engine, is this correct? I know GM changed the ECM's in 1998 to a much more capable unit for better tuning.

I just didn't want to risk using a better/faster unit if it was going to crap out my gauges.

I really want to get the drive train to such a state that it is dependable, efficient for it's purpose and something that will last a long time. I hate being broken down in the middle of nowhere.

Anyway, I hope to hear from you soon. I really appreciate the time you have put in to get me running correctly. This is my first boosted application, and tuned for 93 octane.

Ty

James B.

iTrader: (1)

Lots to cover here but let's begin with your RPM goals.
1. Your PCM does not support more than 5800RPM. This is true of both the 96-97 and the 98-00 design "black box" PCMs. That's a hard limit so you really don't want to get close to it or it can "bounce" off that limiter. You mentioned the later design being more capable, but I'm not aware of any advantage they have over the 96-97 units. They're functionally similar and have different pinouts. The later model has four connectors instead of five, and it's possible to repin the 97 harness to a 98+ pcm, but if you're willing to go to that trouble it would be worthwhile stepping up to a 411 PCM running a custom OS. That's an entirely new thread of discussion many here can help you with.
2. The shortblock is only rated to 5800RPM. This limitation imposed by the fact it's an externally balanced crank shaft. To safely rev higher it needs to be an internally balanced crankshaft - especially on a big block. (Their 572 engines are internally balanced and have higher rev limits.) So, there is some safety margin built into that limit so you can assume an absolute cap around 6000. The Brodix Race-Rites have three different options for valve springs and the ones for hydraulic roller cams have the least amount of seat pressure. Even those springs will support 5800RPM. Beyond that you're getting into solid roller territory. These are not like LS motors with their lightweight valvetrain and hydraulic lifters supplying 7000RPM. This stuff is all just massive and very heavy with lots more inertia.
3. You've got an RPM limit with your supercharger too. We don't know yet what size crank and blower pulleys are on it but this needs to be factored into engine redline.

As for the rattle, not enough information to take a guess. Try to pin it down. If it's easily reproducible by starting the truck use a GoPro or something that take decent video with stereo audio and put it at various places under the truck. If you happen to capture a good sample post it up. Most rattles, in my experience, tend to be interference between exhaust and frame members and/or heat shields.

The dyno - it's not going to be possible to get numbers from a chassis dyno that low in the RPM range. If that's what you really want it will have to be on an engine dyno. I think you already know that will be a massive undertaking. It would need a custom engine harness to do it too.

What kind of torque converter do you have in the 4L80-E? A centrifugal supercharger needs a higher stall speed just like a turbo does to allow the engine to get into power quicker, otherwise laaaaaaag.

I have a ported stock L29 intake on mine with 62# Siemens injectors and a stock PCM tuned shifting at about 5600RPM. It has no problem 5600RPM and tons of torque down low. It does have has very long runners and will choke any higher than 5800 for sure.

I have some videos of the last time it was in the C2500 Suburban to compare yours with. It had a bigger cam then - Cam Spec Card :: Lunati Power
(may have to Save As these because mp4's don't play right in the browsers)
It ran 0-80 like this:
http://bertok.net/pics/502/502-0-80.mp4
Idled and looked like this:
http://bertok.net/pics/502/walkaround.mp4
Sounded like this at idle cutouts closed/open:
http://bertok.net/pics/dougscutouts.avi
Sounded with cutouts opened on the street hauling *** like this:
http://bertok.net/pics/cutoutswot.avi
On a freezing cold morning looked like this:
http://bertok.net/pics/watervapor12-14-12.mp4

The tires on the Suburban are 30.4" and at the time of the above videos it had 4.56:1 gears out back.

You can split any gear with a Gear Vendors Overdrive if you want to but it's impractical. It doesn't disengage when the transmission shifts, so if you split second, for example, and reach a speed when the PCM shifts to third the GV-OD will still be engaged unless you manually disengage it. I use it for Fifth Gear on the highway. That makes the transmission ratio effectively 0.585:1 (0.75x0.78).

As for the gauges, some come from PCM and some come from the chassis. The speedometer signal is processed by the PCM for the cluster to compensate for tire diameter,gear ratio, and transfer case range. The oil pressure, coolant temp, and voltage come from the chassis harness. RPM comes from PCM. Not sure about fuel level but I think that is processed as well. There are two separate coolant temp sensors - one below the t-stat and one in the driver side head. One feeds the gauge the other feeds the PCM. I think the one in the head feeds the cluster but don't recall.

I'm still standing firm the intake is fine and not the problem. I still think the problem is boost - need more sooner.

MikeGyver

iTrader: (5)

Man, bertok.net sure sucks. Every one of those links needed to be reloaded several times to run smoothly from start to finish.