FSC Forum - View Single Post - Common performance-minded FAQs about 88-98 OBS trucks

Red94Chev · 01-05-2008, 06:32 PM

This little piece of software is going to be your new best friend. I often see a lot of questions in the performance section asking "which camshaft to use?" or "which are the best heads for my motor?". Use this program and you can find the best performing engine combination for your purposes, be it at the dragstrip or in your 1/2-ton truck.

Not convinced? Let's do an example using a dynoed engine. Horsepower TV on the Spike network did a "Best Bang for your Buck" series using a GMPP 350 290hp engine. The specs of the engine and dyno results can be found here: http://www.powerblocktv.com/sites/bang4buck/0602/. In summary, they turned the GM 350 crate engine with 290hp-326 ft/lbs into a 412hp-420 ft-lbs performance engine with a complete bolt-on top-end kit from Edelbrock. Looks like they partnered with Summitracing.com and you can even buy this exact combination for $2770.75 using the part# SUM-CBB2 at the Summitracing.com website. I wouldn't reccommend this combination for a truck, but for a lighter street car with a 3000 RPM stall and 3.70+ gears, this is a pretty wicked combination. Click on the video to see the actual build-up and dyno run. So what would be the predicted results using the DD2003 software? Let's find out...

STEP 1: You’re going to need to buy the software. Or alternatively, you can download a pirated copy of the software from sites like Torrentspy and Isohunt. You will need to be familiar with working with torrent files. An additional program is needed to help you download the file, like Bittorrent or Azureus. If you want more info on how to use these programs, search Google, go to the Bittorrent website, or read the Wikipedia link: http://en.wikipedia.org/wiki/.torrent

STEP 2: Install the software and start inputting the engine parameters. There are several sections shown in the figure below: Short block, Cylinder heads, Compression, Induction, Exhaust, and Camshaft sections.

STEP 3 - SHORT BLOCK: This one is pretty easy. If you have 350 engine, click the drop-down arrow and choose Chevy > 8 cylinder SB > 350 V8. The rest of the table is formatted for the standard 350 engine. Now if you have rebuilt your engine 0.030 over, you would change the bore size to 4.030. Notice when you do this, the cid calculated is now 355 ci. You can also choose a 383 V8 SB, a common upgrade for the 350 engine.

STEP 4 - CYLINDER HEADS: Here’s where things get a little more complicated. In order to get accurate simulations, it is best to look up the actual flow data from the manufacturers’ website. The program, depending on the software version and whether you actually paid for the software, comes with some cylinder head data for most common OEM production and aftermarket heads. You can select a particular head for your virtual engine to see the performance results. However, I prefer to enter in the head flow data. For the Edelbrock E-tec cylinder heads and others, the flow data can be found here: http://www.purplesagetradingpost.com...fo/heads1.html. In this section of the software, click the airflow button and enter the specs as shown below.

You will also need to enter the intake and exhaust valve size, in this case for the Etec heads, it is 1.94 and 1.5.

STEP 5 - COMPRESSION: In this case, the Horsepower TV video states the engine compression of 9.5:1, so we’ll enter that into the compression ratio area. If you need to calculate the CR of your engine, you can click on the CR button. Most pistons have valve reliefs, but you don’t need to click on the piston with valve reliefs. I find it more confusing since you cannot zero your piston to the deck height @ TDC. You just have to enter a number that is equivalent to the cc dish of your pistons. These are the common parameters: head chamber (58cc, 62cc, 64cc, or 76cc), gasket bore (4.000”, 4.030”, or 4.060”), gasket thickness (usually 0.028” or 0.051” for GM gaskets; you’ll need to look-up the thickness for Fel-pro gaskets), piston down bore (# in inches that is equivalent to piston cc valve reliefs). For my engine, I would enter 62cc, 4.000”, 0.028”, and 0.0874” to give me 18cc valve reliefs. My calculated engine compression ratio is 9.36:1. Entering this data allows you to calculate what your compression ratio would be if you: 1) changed cylinder heads (58cc for example), or changed engine displacement (either with a 0.030” or 0.060” rebuild or a 383 SB stroker engine. Using the same heads, compression ratio of would be 10.1:1 on a 383 short block with all parameters the same. This would be the max limit using pump gas and aluminum heads. 9.5:1 is roughly your limit with iron heads on pump gas.

STEP 6 – INDUCTION: For the horsepower TV build, they are using a single plane intake so that is what is selected. They are also using a 800 cfm 4-barrel Edelbrock carb (@ 1.5 inHg), so that is entered as well. Flow data for 2-barrel carbs are usually at 3.0 inHg. The exception to this rule is the TBI throttle body, which flows 490 cfm at 1.5 inHg. A modded TB from CFMTech (aka ultimate TBI mods) would flow 590 cfm with the injectors or 620 cfm without the injectors. The TBI engine uses a standard dual plane intake. An air-gap performer RPM intake from Edelbrock would be equivalent to the high-flow, dual plane intake manifold type.

STEP 7 - EXHAUST: If you have the stock log-type set-up, choose “stock manifolds and mufflers”. “HP manifolds and mufflers”, according to the user manual, corresponds to the ram-horn style manifolds. Shortie and long-tube headers are grouped together as “headers”, but separated into small tube and large tube headers. Small tube headers typically have 1-5/8” primaries or smaller, whereas the large tube headers have 1-3/4” primaries or larger. You can model with or without mufflers. There is no parameter for catalytic converters unfortunately. You could assume very little obstruction of flow when two 3” catalytic converters are being used. For the Horsepower TV engine build, small tube headers were used with 1-5/8” primaries. Mufflers were also installed on the engine during dyno runs.

STEP 8 - CAMSHAFT: Here is another place where it is best to look up the specs from the camshaft manufacturers. There is two ways to enter the data; either using valve timing open/closing angles or camshaft duration angles (advertised seat-to-seat or specs at 0.050). You will also need to know the camshaft’s LSA and intake/exhaust centerline angles. DD2003 can use both advertised duration and 0.050 specs to calculate the ramp rate and therefore provide a better simulation when using aggressive high lift camshafts. Here is the cam card for the Comp cam in my ride to illustrate these values: http://www.compcams.com/Technical/Se...umber=08-502-8.

For the horsepower TV engine, the camshaft used is a hydraulic roller retrofit camshaft #2201. The specs for the 2201 camshaft are: duration at 0.006 - 296/300, duration at 0.050 - 234/238, Lift w/ 1.5 rockers - 0.539”/0.548”, lift w/1.6 rockers - 0.575”/0.585”, LSA 112, intake centerline 107, exhaust centerline 117. The figure below shows the entered specs. In the video, the horsepower guys mention they are using 1.6 ratio roller rockers, so I’ll enter the higher lift data.

Do I use the data based on advertised duration (0.006) or the specs at 0.050? According to the user manual for the software, seat-to-seat duration is the most accurate, but occasionally I’ve found that with higher duration camshafts, using valve opening based on 0.050 specs produce more accurate simulations (particularly in the low RPM torque estimates). In this case, the simulation using the 0.050 specs produced a result closer to the actual dyno results.

STEP 9 - THE RESULTS: Shown below is the simulated dyno curve using DD2003 and the specs of the Horsepower TV 350 top end build. The program estimates 409 hp at 6000 RPM and 407 ft-lbs at 4500 RPM. The yellow block highlights the same RPM range given in the actual dyno results, the actual peak data being 411.8 hp at 5800 RPM and 419.8 @ 4500 RPM. Pretty dam close as you can see.

01-05-2008, 06:32 PM	#26
Red94Chev Kick Ass!! Status: Offline Join Date: Sep 2005 Member ID: 33983 Pics: My Gallery Location: Edmonton, AB Age: 33 Posts: 930	Re: Common performance-minded FAQs about 88-98 OBS trucks This little piece of software is going to be your new best friend. I often see a lot of questions in the performance section asking "which camshaft to use?" or "which are the best heads for my motor?". Use this program and you can find the best performing engine combination for your purposes, be it at the dragstrip or in your 1/2-ton truck. Not convinced? Let's do an example using a dynoed engine. Horsepower TV on the Spike network did a "Best Bang for your Buck" series using a GMPP 350 290hp engine. The specs of the engine and dyno results can be found here: http://www.powerblocktv.com/sites/bang4buck/0602/. In summary, they turned the GM 350 crate engine with 290hp-326 ft/lbs into a 412hp-420 ft-lbs performance engine with a complete bolt-on top-end kit from Edelbrock. Looks like they partnered with Summitracing.com and you can even buy this exact combination for $2770.75 using the part# SUM-CBB2 at the Summitracing.com website. I wouldn't reccommend this combination for a truck, but for a lighter street car with a 3000 RPM stall and 3.70+ gears, this is a pretty wicked combination. Click on the video to see the actual build-up and dyno run. So what would be the predicted results using the DD2003 software? Let's find out... STEP 1: You’re going to need to buy the software. Or alternatively, you can download a pirated copy of the software from sites like Torrentspy and Isohunt. You will need to be familiar with working with torrent files. An additional program is needed to help you download the file, like Bittorrent or Azureus. If you want more info on how to use these programs, search Google, go to the Bittorrent website, or read the Wikipedia link: http://en.wikipedia.org/wiki/.torrent STEP 2: Install the software and start inputting the engine parameters. There are several sections shown in the figure below: Short block, Cylinder heads, Compression, Induction, Exhaust, and Camshaft sections. STEP 3 - SHORT BLOCK: This one is pretty easy. If you have 350 engine, click the drop-down arrow and choose Chevy > 8 cylinder SB > 350 V8. The rest of the table is formatted for the standard 350 engine. Now if you have rebuilt your engine 0.030 over, you would change the bore size to 4.030. Notice when you do this, the cid calculated is now 355 ci. You can also choose a 383 V8 SB, a common upgrade for the 350 engine. STEP 4 - CYLINDER HEADS: Here’s where things get a little more complicated. In order to get accurate simulations, it is best to look up the actual flow data from the manufacturers’ website. The program, depending on the software version and whether you actually paid for the software, comes with some cylinder head data for most common OEM production and aftermarket heads. You can select a particular head for your virtual engine to see the performance results. However, I prefer to enter in the head flow data. For the Edelbrock E-tec cylinder heads and others, the flow data can be found here: http://www.purplesagetradingpost.com...fo/heads1.html. In this section of the software, click the airflow button and enter the specs as shown below. You will also need to enter the intake and exhaust valve size, in this case for the Etec heads, it is 1.94 and 1.5. STEP 5 - COMPRESSION: In this case, the Horsepower TV video states the engine compression of 9.5:1, so we’ll enter that into the compression ratio area. If you need to calculate the CR of your engine, you can click on the CR button. Most pistons have valve reliefs, but you don’t need to click on the piston with valve reliefs. I find it more confusing since you cannot zero your piston to the deck height @ TDC. You just have to enter a number that is equivalent to the cc dish of your pistons. These are the common parameters: head chamber (58cc, 62cc, 64cc, or 76cc), gasket bore (4.000”, 4.030”, or 4.060”), gasket thickness (usually 0.028” or 0.051” for GM gaskets; you’ll need to look-up the thickness for Fel-pro gaskets), piston down bore (# in inches that is equivalent to piston cc valve reliefs). For my engine, I would enter 62cc, 4.000”, 0.028”, and 0.0874” to give me 18cc valve reliefs. My calculated engine compression ratio is 9.36:1. Entering this data allows you to calculate what your compression ratio would be if you: 1) changed cylinder heads (58cc for example), or changed engine displacement (either with a 0.030” or 0.060” rebuild or a 383 SB stroker engine. Using the same heads, compression ratio of would be 10.1:1 on a 383 short block with all parameters the same. This would be the max limit using pump gas and aluminum heads. 9.5:1 is roughly your limit with iron heads on pump gas. STEP 6 – INDUCTION: For the horsepower TV build, they are using a single plane intake so that is what is selected. They are also using a 800 cfm 4-barrel Edelbrock carb (@ 1.5 inHg), so that is entered as well. Flow data for 2-barrel carbs are usually at 3.0 inHg. The exception to this rule is the TBI throttle body, which flows 490 cfm at 1.5 inHg. A modded TB from CFMTech (aka ultimate TBI mods) would flow 590 cfm with the injectors or 620 cfm without the injectors. The TBI engine uses a standard dual plane intake. An air-gap performer RPM intake from Edelbrock would be equivalent to the high-flow, dual plane intake manifold type. STEP 7 - EXHAUST: If you have the stock log-type set-up, choose “stock manifolds and mufflers”. “HP manifolds and mufflers”, according to the user manual, corresponds to the ram-horn style manifolds. Shortie and long-tube headers are grouped together as “headers”, but separated into small tube and large tube headers. Small tube headers typically have 1-5/8” primaries or smaller, whereas the large tube headers have 1-3/4” primaries or larger. You can model with or without mufflers. There is no parameter for catalytic converters unfortunately. You could assume very little obstruction of flow when two 3” catalytic converters are being used. For the Horsepower TV engine build, small tube headers were used with 1-5/8” primaries. Mufflers were also installed on the engine during dyno runs. STEP 8 - CAMSHAFT: Here is another place where it is best to look up the specs from the camshaft manufacturers. There is two ways to enter the data; either using valve timing open/closing angles or camshaft duration angles (advertised seat-to-seat or specs at 0.050). You will also need to know the camshaft’s LSA and intake/exhaust centerline angles. DD2003 can use both advertised duration and 0.050 specs to calculate the ramp rate and therefore provide a better simulation when using aggressive high lift camshafts. Here is the cam card for the Comp cam in my ride to illustrate these values: http://www.compcams.com/Technical/Se...umber=08-502-8. For the horsepower TV engine, the camshaft used is a hydraulic roller retrofit camshaft #2201. The specs for the 2201 camshaft are: duration at 0.006 - 296/300, duration at 0.050 - 234/238, Lift w/ 1.5 rockers - 0.539”/0.548”, lift w/1.6 rockers - 0.575”/0.585”, LSA 112, intake centerline 107, exhaust centerline 117. The figure below shows the entered specs. In the video, the horsepower guys mention they are using 1.6 ratio roller rockers, so I’ll enter the higher lift data. Do I use the data based on advertised duration (0.006) or the specs at 0.050? According to the user manual for the software, seat-to-seat duration is the most accurate, but occasionally I’ve found that with higher duration camshafts, using valve opening based on 0.050 specs produce more accurate simulations (particularly in the low RPM torque estimates). In this case, the simulation using the 0.050 specs produced a result closer to the actual dyno results. STEP 9 - THE RESULTS: Shown below is the simulated dyno curve using DD2003 and the specs of the Horsepower TV 350 top end build. The program estimates 409 hp at 6000 RPM and 407 ft-lbs at 4500 RPM. The yellow block highlights the same RPM range given in the actual dyno results, the actual peak data being 411.8 hp at 5800 RPM and 419.8 @ 4500 RPM. Pretty dam close as you can see.