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Horsepower, Reading, Research, Options

This is a discussion on Horsepower, Reading, Research, Options within the Internal Engine forums, part of the LSx Technical Help Section category; The topic of this is NOT a "How to reach XXX RWHP" thread, its merely trying to show members some ...

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    Post Horsepower - Reading, Research,Options,Information

    The topic of this is NOT a "How to reach XXX RWHP" thread, its merely trying to show members some basic insight on how to reach certain power levels the desire. Additionally, The thread is meant to have a good overview of general information on several popular topic's or questions.

    -Compression
    -Great flowing Cylinder heads
    -Great flowing Exhaust system
    -Great flowing Intake system
    -Losing the "Extra" systems
    -Camshaft Selection
    -Nitrous
    -Stroker Engines
    -Fuel pumps, injectors
    -Difference's in LS1/LS6

    Compression -

    One way to squeeze out a few more horsepower even after porting. Accomplished by milling the cylinder head deck surface to decrease the chamber volume. There are many compression calculators out there, but usually the normal going rate is around 11ish/1 on 91 or higher octane. This of course can depend on your camshaft and other parts of your setup. Shoot for around 11ish/1 compression on a naturally aspirated LSx engine. When milling the cylinder heads you are in turn bringing the valves closer to the piston, decreasing PTV ( Piston to Valve ) clearance. You must take this into consideration when buying a aftermarket camshaft. You can also sway your CR by different thickness head gaskets. Stock is .053" Non stock valve sizes will greatly reduce PTV. (Stock LS1 valve sizes are intake 2.00" and exhaust 1.55") Flycutting is an option when you have less then the desired .080 intake and .100 exhaust clearance. Flycutting will remove material from the piston to make room for the valve. Raising your static/dynamic compression will increase torque output. Roughly 1 point in raised compression will increase torque 3%-4%. Intake valve closing point decides dynamic compression. Trading your flat top piston for a domed piston will increase CR greatly. That's a another whole topic though, as it goes into replacing many parts. 5.3 heads will give a bump in compression immediately. A good thread to read on compression. http://www.gmhightechperformance.com...ion_ratio.html

    Static Compression - The SC RATIO is defined as the Volume of the Combustion Chamber when the piston is at the very bottom of it's travel (called "bottom dead center" or BDC) DIVIDED BY the Volume of the Combustion Chamber when the piston is at the very top of it's travel (called "top dead center" or TDC) For NA purposes, you can get away with low/mid 11:1 SCR. For Forced induction, it will depend on many factors of your build, but anywhere from 8.5 to low 9.0's SCR is usually the numbers guys are going for.

    Dynamic Compression - The Compression Ratio (CR) of an engine is the ratio of the cylinder volume compared to the combustion chamber volume. A cylinder with 10 units of volume (called the sweep volume) and a chamber with a volume of 1 has a 10:1 compression ratio. Static Compression Ratio (SCR) is the ratio most commonly referred to. It is derived from the sweep volume of the cylinder using the full crank stroke (BDC to TDC). Dynamic Compression Ratio, on the other hand, uses the position of the piston at intake valve closing rather than BDC of the crank stroke to determine the sweep volume of the cylinder. For NA setups, you should shoot for mid 8's. High 8's are attainable with the right parts and a very solid tune. Cant stress the tune too much there.

    Compression calculators -
    http://www.angelfire.com/fl/procrastination/motor.html
    http://www.csgnetwork.com/compcalc.html
    http://www.zealautowerks.com/

    Cylinder Head Milling - A easy way to bump compression. But milling too much can hurt head flow greatly. Welding the chambers properly is a known effective way to raise compression and keep flow. Subtracting .080/.100 from measured PTV clearance will tell how much is safe to mill. At a certain point of milling, the intake is not going to line up. There are maximum amounts of milling that can be done. It takes approx .007" to remove 1CC from a LS1 cylinder head.

    Cylinder Heads -

    Cylinder heads vary. And you usually get what you pay for. AFR, TFS, WCCH, ETP all do a SUPERB job in flowing great numbers. The contenders are PRC and Patroit. Both cheaper heads that will still get the job done for most applications. When looking at cylinder heads you must look at the valve angle. It not only means better air flow, but usually will mean a different valvetrain setup is required, ie Pushrods, rocker arms etc. Of course you can always get your stock heads ported. 243 casting being the top head that came stock. You can find your casting number stamped onto the head in one of the corners on either head. Companies like TEA,CarTec, do port work, along with many others. Make sure you have a REPUTABLE porter do the work. 4 bolt VS 6 bolt heads. A stock LSx block will have a 4 bolt design. For most applications this will suffice. For High HP using Nitrous or FI, A 6 bolt block might be needed to prevent pushing water. Cylinder heads STUDS are better then any bolt. ARP studs are nice pieces.

    Stock valve angles are 15*. That's the angle of the valve STEM and the cylinder bore centerline. When you DECREASE this angle ( in degrees ' * ' ) you gain piston to valve clearance. Having a valve angle such as a ETP head produces will allow you to run a smaller chamber ( More compression ) to a point of not having PTV issues. Lets get valve angles straight for those that don't know.

    Stock LS1 - ( 241, 243, 853, 799, 862, 317) angle - 15*
    Trick Flow - 13.5*
    AFR - 15*
    ETP - 11*
    West Coast Cylinder Heads - 12*
    Some reading can be done. Ive searched so many sites, Ive forgotten most. Here's a few that touch on the valve angle ideology. http://speedtalk.com/forum/viewtopic.php?t=3080
    Stock Combustion chambers are -
    241 - 66CC
    243 - 64CC - LS6 Head
    317 - 71CC
    L92 - 70CC
    853 - 66.67CC
    862 - 61.15CC - 5.3 Head
    706 - 61.15CC - 5.3 Head
    873 - 71CC - Cast Iron
    035 - 71CC
    799 - 66.67CC - LS2 Head, Same as 243
    Runner port volume vary. Stock Port volume is 205CC. The AFR 205's are hard to beat on mid lift airflow and horsepower. 225CC ports should be consider 402 CI or higher territory.
    *** Read this webpage on basic LS1 cylinder head specifications - http://www.smokemup.com/tech/ls1.php ***

    L92 heads are a great head. Based off the LS7 head design, they flow huge numbers right out of the box. And for a very nice price. *** Read this page for L92 information,
    L92 valve size -
    2.160" intake valve
    1.590" exhaust valve

    http://www.gmhightechperformance.com...ads/index.html
    http://corvetteactioncenter.com/spec...ls3_page1.html

    Want a general review on the top main brand heads? CLICK HERE FOR REVIEWS

    Stock valve guides are sintered iron. Most ( if not all ) aftermarket heads are bronze valve guides. Match that with a non-stock valve angle and a high lift camshaft (.610"+) and you will have increased valve guide wear that will lead to smoking upon start up and hard acceleration or high RPM deceleration. An adjustable rocker arm should always be considered when going to a non OEM valve angle, bronze valve guided head, or a high lift camshaft as all can cause increased valve guide wear.

    Firing Order -
    1 - 8 - 7 - 2 - 6 - 5 - 4 - 3

    Rocker Arms -
    Stock rocker arm ratio is 1.7. This number is important for figuring out your final camshaft lift. For example, my camshafts lift on intake is .337". ( 1.7 x .337 = .5729) and for exhaust ( 1.7 x .340 = .578 ) So increasing your rocker arm ratio will increase your net valve lift. Simply input your camshafts lobe lift and multiply it by your rocker arm ratio for your final lift. If you have no future plans of adding an aftermarket camshaft, then a higher ratio rocker arm ( 1.8 ) might be for you. It will add approx 10 HP with supporting modifications. Now, with your higher ration rocker arm, that will limit your future camshaft choices as it increases your lift by multiplying. Its better to keep a stock ratio and buy a camshaft with the lift you desire. There are many brands to choose from and many retailers. Harland Sharp, Yella Terra, Crane, Jesel, Scorpian rebuilt stockers. The stock rocker arms are the lightest, and very strong. If your applications does not require an aftermakret rocker, stick with the stock piece and maybe have them rebuilt. Harlan Sharp rebuilds them and COMP sells a rebuilt kit. Stock rockers are NON adjustable. Just tighten them down to 22 ft lbs, turn the engine over a few times and re-check. Pull the two connectors going to your coil packs and your fuel pump fuse. This will allow you to turn the engine over and not start the car. Here's a diagram on torquing the rocker arms. Ive never personally done the diagram's procedure on my setups, but maybe you will.
    Click for full size

    A good link on rocker arms - COMP CAMS ROCKER ARM FAQ

    Link to Harland Sharps stock rocker upgraded rebuild found here -
    http://www.harlandsharp.com/conversion%20kit.htm
    Last edited by Hi-Po; 01-05-2010 at 01:39 PM.

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    Rebuilding your stock rockers with this HS upgrade is strongly recommended for aftermarket Camshaft swaps and springs with higher pressures. At 260$, its a very good deal. Click on the thumbnail below to see a rocker arm needle bearing/rocker arm that has lost them.
    Click for full size

    Here's the Technical Service Bulletin for the needle bearing failure on Stock rocker arms
    http://www.corvetteactioncenter.com/...Rocker+Arms%29

    For part numbers, including gaskets, sensors, Seals, internal/external part number's, Head Information and Spec's LOOK HERE This website is a good website for LOTS of information.

    http://www.theturboforums.com/smf/in...=122987.0;wap2

    SES Code Description and Diagnosis

    http://gearchatter.com/

    Exhaust System - Start by reading these,

    The Complete (Hopefully) Header Thread
    Best headers, best catback, soundclips etc.
    True Dual exhaust read me. pics/and share your information.

    Not going to go into the exhaust too much here as it is discussed greatly in the those threads.

    Intake systems - The best intake out right now for LS1/2/6 cathedral port headed based engines is still the FAST. L92 and LS3/7 heads will require a different intake as they are a rectangular port design. L76, FAST 102mm, LS3, LS7 intakes will all work. If you have a stock 97-2000 LS1, adding a LS6 intake is a great modification. Further in the thread is a thumbnail picture of LS1/LS6 intake flow comparison. FAST intakes will flow even better then the LS6. To my knowledge, the only difference between the FAST 90mm and FAST 92mm intakes is the 2mm increase in mouth size. That will show hardly any (if at all) horsepower gain. Porting can be done to the FAST intakes as they are a two piece design. Gains from porting can vary, but usually will show a very nice HP gain. **Intake comparison dyno graphs shown below**

    Horsepower by deletion - Aftermarket electric water pumps are a must if your trying to squeeze every last HP out of your engine. They are also very nice for being able to cool your engine while waiting in the staging lanes. Same goes for ditching AC. Not only will deleting the AC system get rid of weight over the nose, it will free the engine from that extra drag. Removing the belt can also be looked at. Manual power steering racks can also be looked at. Adding an underdrive pulley(s) to squeeze that little extra out. Doing all the "free" modifications.

    Under Drive Pulley's -
    ATI -
    SLP - $179.00
    ASP - $214.00 - Crank
    ASP - $24.00 - Alternator
    PowerBond - $200.00
    BBK - $229.00

    SLP, Powerbond, and ATI are all good underdrive pulleys with higher walls to aid in belt alignment. They will all show the same average horsepower gains. They don't so much add any HP, rather they reduce HP loss by spinning the accessories slower. Generally people don't have charging issues. If your having problems throwing belts, the Katech solid belt tensioner is great. My belt began to 'walk' off and after installing the Katech tensioner, I never had a problem again. Its a great piece that looks sharp.

    Katech Solid Belt Tensioner - $135.00

    Consider reading this webpage. Its very basic, but is a good way to remind you of the smaller things. http://books.google.com/books?id=AbJ...angles&f=false

    Strokers - 402CI+ - LQ4, LQ9 blocks -

    The easiest way ( not the cheapest way ) to get big Horsepower, maybe your magical 500 RWHP would be to transplant a larger cubic inch engine into your fbody/LSx. If your going to try and tackle it yourself, Iron blocks are very easy to find. LQ4 and LQ9 are the same 4" bore iron blocks. Install a 4" throw crankshaft and you have 402 CI. Bore the Iron block .030" over with the same 4" crank, and you now have a 408 CI. Boring over .030" and you should start thinking about getting the block sonic tested for thickness. If you don't mind the extra weight of an iron block up front ( Roughly 88 LBS ), this is a very cost effective way to get a stroker. You can also go with a LS2 block (aluminum), for an extra cost fee. The iron blocks are almost a complete matching drop in ready replacement block. Drilling and tapping a hole for the alternator will be needed. 402 iron shortblocks with Eagle components start at roughly 3200 dollars. The cost starts going up exponentially when you start adding better forged internals, aluminum block, custom piston, LS2 conversions, balancing, shipping, different bearings etc. If you want 500 HP, it will be much easier to go larger cubes. 402 CI + is a pretty cheap starting point. 400 or 450 RWHP is a much more attainable goal on stock cubes, with 450 being on the higher end. More CI will make more power, in a more usable area in the RPM.

    Stock LS1/LS6: (Aluminum Block)
    Bore: 3.900"
    Stroke: 3.622"
    Rod Length: 6.100"

    Stock LS2: (Aluminum Block)
    Bore: 4.00"
    Stroke: 3.622"

    Stock LQ4: (Iron Block)
    Bore: 4.00"
    Stroke: 3.622"
    Compression Ratio: 9.4/1

    Stock LQ9: (Iron Block)
    Bore: 4.00"
    Stroke: 3.622"
    Compression Ratio: 10.0/1




    Camshafts -
    Without going into too much detail here, I'll post some links. The easiest way to get a cam for you is to call a spec shop.
    http://www.compcams.com/Technical/FA...eQuestions.asp
    Camshaft Guide - Information / Write up
    Dealing with Lobe separation Angle - http://www.compcams.com/Technical/FAQ/LSAproperties.asp
    http://www.lgmotorsports.com/catalog/index.php
    http://www.lmperformance.com/h/1/.html
    Those are some good links to some good companies. A custom cam tailored to your setup will 9 time out of 10 work better and produce more HP where you want/need it. Google PatG, Cam motion, COMP, LG MotorSports, they can all spec you a cam.

    Base Circle Dia.:
    '97-'04 LS1 = 19.7mm / 0.776"
    '01 LS6 = 19.3mm / 0.760"
    '02 -'04 LS6 = 19.0mm / 0.748

    Stock Camshafts
    1997-2000
    0.472/0.479, 202/210 on 117

    2001 LS1
    .500/0.500, 198/208 on 115.5LSA

    2001 LS6
    0.525/0.525, 204/211 on 116

    2002 LS6
    0.551/0.547, 204/218 on 117.5

    Lifters -
    If you were to replace your LS1 lifters with stock LS1 lifters, you would recieve LS7 lifters. There is technically no "LS1" lifter PN. They were designed to work with a stock LS1 engine. Now, that said, the LS7 lifters cup is roughly .050" to .060" taller then your stock old LS1 lifter. This in turn, requires a shorter pushrod. You MUST measure. To properly check/measure lifter preload read this informative "how-to" by CLICKING HERE.

    Pushrods - You MUST measure these when changing/swapping camshafts heads or modifying. Here's a great run down on measure pushrod length,

    Shane at Thunder Racing gets the credit.

    "The TDC method is NOT always accurate. Try the EO/IC method to check pushrod length. I have posted directions on this forum numerous times... Here it is again:

    FWIW, EVERY cam install I have done using the LS7 lifter with a cam with greater than .600" lift (read smaller base circle) AND stock heads w/GM MLS gaskets has taken 7.425" pushrods for ~.050"-.060" preload. We measure lifter preload on each and every cam install we do. I have never had a lifter failure nor do we end up with the dreaded "sewing machine" noise.

    Its very simple, If you change ANY of the following:
    valve sizes, valve job, head milling, thinner/thicker head gaskets, decked block, cam with an altered base circle, etc... YOU MUST CHECK FOR PROPER PUSHROD LENGTH.

    I have helped countless numbers of individuals with this process over the phone, via email, and PM's. I've posted the process on at least 3 occasions.

    Here it is again in a nutshell:

    1. Using the EO/IC method, get the lifter to the base circle of the cam.
    2. Using a known length pushrod (7.400" is a good start with stock rockers) run the rocker arm bolt down to zero lash. This is easily done with your fingers "wiggling" the rocker, the point at which the "slack" is just gone is zero lash.
    3. Set your torque wrench to 22 lb./ft. Tighten the rocker to full torque and count the number of turns it takes to get there. 1 full turn with a stock 8mm X 1.25 bolt is ~.047" preload as measured at the pushrod/rocker interface.
    4. I normally shoot for 1 1/4 to 1 3/4 turns with stock type lifters like Comp 850's, LS1, LS7 etc.

    For an example, if you use a 7.400" pushrod and come up with 3/4 of a turn, you will need at least .025" longer pushrod to get into range. If you end up with 2 1/4 turns, you will need one .025" shorter...

    I might not know everything but I will tell you that this method has worked for me year after year cam swap after cam swap. We average 3 cam swaps a week here so you can do the math.

    If you are not familiar with the EO/IC method for determining valve events in a 4 stroke engine, its very simple:
    For a given cylinder as the Exhaust valve is Opening, the intake lifter will be on the base circle of the cam and lash/preload should be checked for that intake valve.
    For a given cylinder as the Intake valve is Closing, the exhaust lifter will be on the base circle of the cam and lash/preload should be checked for that exhaust valve.

    THIS METHOD ALWAYS WORKS!!!
    Last edited by Hi-Po; 01-05-2010 at 01:30 PM.

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    Check it using the above method and see where you are."

    A cheap Pushrod length checker can be found here,
    http://www.jegs.com/i/JEGS/555/80681...oductId=758609 and here,
    http://www.speedwaymotors.com/Pushro...ecker,225.html

    Fueling, Injectors, Lines, Pumps, Filters

    LS1 Static Flow Rate = 3.6 gal/sec.
    Cranking Fuel pressure = 53 to 63 psi
    Normal pressure for stock LS1 fuel system is 58 PSI. At WOT, my Fbody's PSI drops to roughly 52-54PSI, and with key on-engine off it sits at 55PSI for cranking. Generally fuel injectors are maxed out at 80% duty cycle. Duty Cycle is described as a ratio of on to off time or percentage something stays on. This duty cycle can be viewed with any high end scanner such as HPTuners or EFI Live. For a website that greatly helps decide what size, HP value, Ful flow AFTER pressure change, conversion charts, and fuel injector worksheet click Click Here

    Fuel Pumps - Great Walbro pump install write up, FUEL PUMP INSTALL
    Wiki - The AN thread is a particular type of fitting used to connect flexible hoses and rigid metal tubing that carry fluid. It is a US military-derived specification stemming from a joint standard agreed upon by the Army and Navy, hence AN.

    "An easy way to mentally convert an AN dash size to the nominal fractional equivalent is to remember that the dash number is the numerator of a fraction with a denominator of 16. For example a dash 10 is 10/16ths or 5/8" while a dash 16 is 16/16ths or 1" and so on." - Russell Performance

    AN Dash Size | Nominal Equivalent | Hose I.D.
    3---------------3/16"----------------1/8"
    4---------------1/4"-----------------7/32"
    6---------------3/8"-----------------11/32"
    8---------------1/2"-----------------7/16"
    10--------------5/8"-----------------9/16"
    12--------------3/4"-----------------11/16"
    16---------------1"-------------------7/8"

    Stock Fuel injectors are:
    '98 or '01+ = 28.6
    '99-'00 = 26.4

    If you need to figure out what injector to use for your horsepower application, you the calculator link below. Its very helpful.

    FUEL INJECTOR CALCULATOR

    Nitrous

    Nitrous is the quickest way to reach a higher HP goal. Done correctly it can be very safe, even on a stock LSx motor.

    Read these webpages to get a good grasp on the different systems available. Differences between wet and dry are discussed below.
    http://www.go-fast.org/z28/new_to_nitrous.html
    http://en.wikipedia.org/wiki/Nitrous
    http://www.tuninglinx.com/html/nitro...-tuning-2.html
    http://www.ls1tech.com/forums/nitrou...s-related.html
    If your question is, " How to add XXX amount of HP the cheapest/quickest way" Nitrous is a very short answer to the question.

    Add any, or all of them and get the power your looking for.

    Getting this power to the ground is sometimes ( usually ) forgotten about. Front and rear sway bars, Sub frame connectors, aftermarket springs/shocks, Lower control Arm, LCA relocation brackets is a start.Not going to go to in depth right now with this subject. How to pick a rear?

    Here's a good book to read. [ame]http://www.amazon.ca/How-Build-Modify-LS-Engines/dp/0760335435/ref=sr_1_2?ie=UTF8&s=books&qid=1258664701&sr=8-2[/ame]

    LS1 to LS6 difference's and similarity's -

    2002 LS6 got received sodium filled exhaust valves
    Both have 6 bolt main bearing caps. ( 4 vertical and 2 horizontal )
    Oiling system was upgraded on the LS6. With roughly 500 more RPM, a larger window at the bottom of the cylinder was added. In the picture ( thumb nail, click to enlarge ) you can see a cutaway of a LS6 block. Notice the large window cut.

    Click for full size
    Both blocks use cast gray iron liners. Both bores are 99 MM ( 3.8976 in ).
    Cranks are the same, cast nodular iron with a stroke or 92MM ( 3.6620 in ). Both have the same displacement of 5.665 liters or 345.69 cubic inches.
    LS6 cranks use a different dampener with an aluminum hub that is 2.6 LBS lighter then the LS1 dampener.
    LS6 received a larger MAF (Mass air flow) from the 6.0 liter truck engine
    Compression ratio was bumped four (4) tenths to 10.5/1. This was accomplished by decreasing the chamber size of the cylinder head.
    Exhaust ports are different with LS6 heads. LS1 exhaust ports have an "Oval" shape. The LS6 exhaust port is " D " shaped.
    Both use Mahle pistons. LS6 pistons are referred to as M142 which is silicon and nickle. LS1 pistons are referred to as M124. Mahle 142 (LS6 piston) is stronger and offers less heat expansion at high temp's.
    Camshaft changed slightly. Still a steel billet, rifle drilled for less mass.
    Intake ports changed greatly from the LS1 heads to the LS6 heads. Click on the thumbnail picture below to see the major changes in the short turn radii and port floors.
    Click for full size
    Both Gen III and Gen IV engines share:
    0.842-inch lifter bores
    Four-bolt-per-cylinder head bolt pattern
    9.24-inch deck height

    Obviously LS6 received the LS6 intake rather then the LS1 intake. Click the thumbnail below to view how the LS6 intake carries on well past the LS1 intake. An increase in plenum volume from the LS6 intake is nets about a 10 HP increase over an LS1 intake.

    Click for full size



    Have some thing to add to this thread? PM me, and we can add it.

    * All these links provide ALOT of information. Please read them *
    Last edited by Hi-Po; 01-05-2010 at 01:34 PM.
    370 CI - Twin 6766 Turbo - Jakes stage 5 4L80E - MWC 9" - Holley Dominator

    Build in progress...

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    Intake Comparison's - I found some nice Dyno graphs comparing intakes from vetteweb. Thought I would share.


    GRAPH 1: Stock LS2 Intake vs. Edelbrock Performer RPM Our first intake test involved a dual-plane Edelbrock Performer RPM. Coupled with a Barry Grant 750 Mighty Demon carb, the Performer RPM actually outperformed the factory LS2 intake from 3,000 to 4,500 rpm. From 4,600 to 6,500 rpm, the LS2 manifold battled back and pulled ahead by 12 to 15 hp. This was an interesting comparison, since the LS2 intake features long runners, which tend to promote midrange torque. It just goes to show that every intake must be optimized for its combination


    GRAPH 2: Stock LS2 Intake vs. Edelbrock Victor Jr
    We expected the single-plane Victor Jr. to yield a loss in low-speed torque, combined with an increase in top-end power. True to form, the Victor Jr. lost power down low compared with the factory LS2 intake. But strangely, the Edelbrock manifold only managed to equal the horsepower production of the stock LS2 unit from 5,000 to 6,500 rpm. Compared with the dual-plane Performer RPM, the Victor Jr. offered more power at the top of the rev range. The LS2 intake, however, showed the best overall power curve of the three.


    GRAPH 3: Stock LS2 Intake vs. LS1 Intake
    Although replacing the LS2 intake with an LS1 unit resulted in the expected drop in power, the two intakes performed almost identically up to 5,100 rpm. From there, the LS2 bested the LS1 by as much as 11 hp.Part of the credit surely goes to the larger 90mm throttle body on theLS2. For this test session, both intakes were run with FAST throttle bodies--a 78mm on the LS1 and a 90mm on the LS2.


    GRAPH 4: Stock LS2 Intake vs. LS6 Intake
    The LS6 intake not only produced more peak power than the LS2, but it also outperformed the newer-style manifold from 3,700 to 6,500 rpm. We suspect that if the LS6 intake had been configured with a 90mm throttle opening, the difference would have been even more dramatic. Based on this test, it looks like (non-Z06) C6 owners would do well to swap out their factory intake for an LS6 unit.


    GRAPH: 5 Stock LS2 Intake vs. FAST LSX Intake (78mm throttle body)
    The 78mm LSX manifold (and matching 78mm FAST throttle body) easily outperformed the factory LS2 intake from 3,000 to 6,500 rpm. Equipped with the LSX, the LS2 motor produced just under 500 hp but actually bettered the larger 90mm version down near 3,000 rpm. The lesson here is that you can't go wrong with either version.


    GRAPH 6: Stock LS2 Intake vs. FAST LSX Intake (90mm throttle body)
    The 90mm LSX offered all the mid range power of the LS6 intake along with an extra helping of top-end power. Like the LS6 unit, the 90mm LSX improved the power output of the LS2 crate motor from 3,500 rpm all the way to 6,500 rpm, and even showed a few extra horsepower down at 3,000 rpm
    Last edited by Hi-Po; 12-26-2009 at 05:44 PM.

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    Great post Hi-Po
    I believe it's sticky worthy
    Craig
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    Gone but not forgoten
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    1 of 1 Build Date 3/12/98

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    im glad that some one is finally posting 'tech' in our tech forums, instead of the same questions.

    hopefully this gets a sticky so i can easily reference it in the future.

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    great read and great info Hi-Po!

    you need to quit your job and get an engine/ mechical tech teaching job!

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    ron THANK YOU! ..we need more technical stickies like this on ls1.com.

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    Great post for the normally aspirated engine, but 500rwhp is the norm for a supercharger installs according to A+A and ECS and that's on a stock bottom end.

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    Veteran Hi-Po's Avatar
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    Quote Originally Posted by azfrc View Post
    Great post for the normally aspirated engine, but 500rwhp is the norm for a supercharger installs according to A+A and ECS and that's on a stock bottom end.
    There is no mention of FI really. I wasnt really going for, Pick A to get this B HP. Its just some good general information, with a few good quality links to some good reads. This thread took the back burner.

    Im starting to work on a Excel Spread sheet on all the different cylinder heads brands comparisons. Ive stopped quarter way through.

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    Junior Member need4fun2469's Avatar
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    I hope you continue to write informative posts. I have learned from this.

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    Senior Member grouch0jr's Avatar
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    Quote Originally Posted by Hi-Po View Post
    There is no mention of FI really. I wasnt really going for, Pick A to get this B HP. Its just some good general information, with a few good quality links to some good reads. This thread took the back burner.

    Im starting to work on a Excel Spread sheet on all the different cylinder heads brands comparisons. Ive stopped quarter way through.
    what type of information were you planning on including in the document? flow rates? combustion chamber sizes? compression ratios?

  13. #13
    your parts guy!!! 1fastcamarosss11's Avatar
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    i want to finish reading this later. great post.

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    Veteran Hi-Po's Avatar
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    Quote Originally Posted by grouch0jr View Post
    what type of information were you planning on including in the document? flow rates? combustion chamber sizes? compression ratios?
    Yup. Heres what I have on the speadsheet so far.

    Casting Number, IN Valve size, EX Valve size, Chamber CC, Intake CC, Exhuast CC, Part Number, Flow .100, .200, .300, .400, .500, .550, 600.

    Different things could be added for sure. Maybe CR, but it would have to be asumed that the numbers are for STOCK LS1/2/6 LQ4/9 shortblocks.

    You get the idea. Right now, Im almost done with stock heads. I will have to sit down and search for real data on heads. Flow numbers might be difficult to keep in line on a speadsheet only because people use different test bores and valve sizes.

    Its not going to happen overnight.

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    thank you for taking the time to build up a spread sheet of data. if you post it in a different thread for a sticky. it would be nice if you dropped a post here linking to it, thanks. i can't wait to read it.

  16. #16
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    i cant tell if this got a sticky but it better. good info but i have to really second guess the 3-4% gains for one point of CR.. so if u bump up .1 and u have 360 tq ur going to see a tacked on 11ft lbs thats a lot... just changing from stock head gaskets .053 to stock mls .051 ive seen .2 cr gains... thats 22 ftlbs by using stock parts

    and i would also like to see the limmit of what u can mill off the heads added some where on this write up...

    but HiPo nice job

  17. #17
    cutting and welding mark21742's Avatar
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    Quote Originally Posted by blackbirdbrain89 View Post
    i cant tell if this got a sticky but it better. good info but i have to really second guess the 3-4% gains for one point of CR.. so if u bump up .1 and u have 360 tq ur going to see a tacked on 11ft lbs thats a lot... just changing from stock head gaskets .053 to stock mls .051 ive seen .2 cr gains... thats 22 ftlbs by using stock parts

    and i would also like to see the limmit of what u can mill off the heads added some where on this write up...

    but HiPo nice job
    the best way to get super high compression is to weld the chambers up then CnC them to the shape you need and run a dished piston......this way combution is centered on the piston, not out toward the ring lands like you'd have with a domed piston

  18. #18
    Veteran Hi-Po's Avatar
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    Quote Originally Posted by blackbirdbrain89 View Post
    i cant tell if this got a sticky but it better. good info but i have to really second guess the 3-4% gains for one point of CR.. so if u bump up .1 and u have 360 tq ur going to see a tacked on 11ft lbs thats a lot... just changing from stock head gaskets .053 to stock mls .051 ive seen .2 cr gains... thats 22 ftlbs by using stock parts

    and i would also like to see the limmit of what u can mill off the heads added some where on this write up...

    but HiPo nice job
    Typically, for every FULL point it will show in the neighborhood of 3-4%. Not .1 but 1.0

    That is a pretty general rule of thumb. It could be more/less.
    Last edited by Hi-Po; 12-18-2009 at 04:43 PM.

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    Veteran 0rion's Avatar
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    good post bro

  20. #20
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    could you expand a little more on the need of different sizes of fuel injectors?

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