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Thread: SR20VE 101. The good info.

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    sss4me's Avatar
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    SR20VE 101. The good info.

    Great quotes from the past, still relevant today. please feel free to add, if you KNOW its right. no stupid questions.

    "N1 cams make peak HP from 7800 to 8400 RPMs depending on what motor configuration they are on like headers and intake for example".

    "Springs/retainers will not really make more peak HP because N1 cams are not starting to float the valves until above 8500rpms. With a great header , and the correct intake on it, with the cams setup right and tuned you should see peak WHP close to 8000rpm. The motors that are peaking at 7000-7200rpm are not tuned correctly, or they do not have a good header. The SSAC really limits the potential of the N1 cams, especially above 7000rpm."

    "as for setting up the N1 cams. If you are setting the cams up by "guessing" at what centerlines to run, or "so and so ran this and made this here so i'm gonna do this instead" Then you really dont know what is going on with the valve events and why the N1 cams are ground with the profile that they do have. the VE motors still respond to the same similar centerlines as the DE motor does but with a higher flowing head. people started doing the +4-4, +5-5 thing because of a few people years ago that started testing them on the dyno and yes it has trickled down the ladder but that doesnt mean it is the best or will work best for your setup. Exhaust valve opening and header design go hand in hand so what works with one header may not work with another one as well.

    the only TRUE way to setup ANY camshaft(s) is by degreeing them in an knowing where u are starting at with the opening/closing events and C/L's"


    "The N1 cams are not designed for a 2.0L motor and thus the opening/closing ramps and centerlines are designed around a 68.7mm stroke with a 2.10 R/S ratio and with less displacement these cams are not anywhere near optimized for a 2.0L motor. these are designed around the VE head though as the 1.6 and 2.0 heads are the same casting and have the same/similar flow properties.

    "The main thing that is needed for a lot of power from these motors is yes cams, but besides that, before that, you need a lot of intake flow. That includes the cylinder head AND the intake manifold. The N1 is not designed for a 2.0L motor and will actually max out the flow and have low port velocity on a 2.0L or larger motor."

    " There are problems with the VE head in running a cam over 12.7mm lift. more so above 13.0mm lift. there is modification needed to several parts to get this to work in the head and it is no where near drop in. The highest amount of lift you can go for a drop in cam is 12.7mm IN and 12.46mm EX roughly. that is where the cam lobe will contact the rocker arm".

    "the biggest power gains that I have seen with these motors is with the header design, the collector megaphone used and also the quality of the header built and they way it is built. the other aspect is tuning. Someone mentioned how the VE's like a lot of timing.... If you are adding a lot of ignition timing to gain power, then you are not running a very efficient setup. the more ignition timing needed means that you are not achieving a high cylinder fill because the more air/fuel in the cylinder at a higher pressure means that the A/F burns at a faster rate. If you have a very efficient setup with the proper cam timing and proper header you will be running much less ignition timing. If you are running 34-38 deg timing at 7-8000rpm like some people have stated then you are not making anywhere near what your motor should be making if you had the proper header.... N1 cams set at the "proper" cam specs and a tuned length header ( less than 30" with megaphone/reverse cone) will want less than 30 deg timing to make the most power"

    "As for a basic port job making 300CFM, I would say otherwise. Only the Early production VE heads are the "good" ones because they do not have any core shift. The later heads have enough core shift that unless you weld the head up or Install larger valve seats you will be left with a few large steps from the port to the valve seat. A stock VE head flows anywhere from 235cfm-274cfm @ .500" lift. with no good cams to lift that high, the number that we should be worried about is .450" lift, just under 12.0mm. I have seen several pics of people with "ported" heads on many forums including this one and all people seem to do is stick the gasket on the intake surface and port the runner opening in the head out as large as they can and then leave the Valve pockets and throats stock and dont even give it a good valve grind or any grind at all. Some of the cheapest power can be picked up in a good valve grind. Factory valve grinds are not made for power but for longevity".

    "A SR16VE N1 Exhaust cam has about 330 deg duration at .004" lift at the valve. that is a big duration cam. HOWEVER it has one of the smoothest ramps of any camshaft out there and because of its profile, depending on the exact stock VE valve spring harmonics, you may be able to rev to 10,000rpm on stock springs before valve float may occur. The N1 cams have 250 @ .050" Exhaust and 249 @ .050" IN duration. the IN is about 305 Deg @ .004" lift. Now all of these cam measurements are dependent on correct valve lash. Such as HOT valve lash because that is the clearance that the engine runs with. If in doubt measure with "0" lash first then at cold specs and again at Hot specs.

    Getting NA drop in cams for the VE is not a hard thing to do. Getting them to make power is. I have flowed several stock VE heads ranging from 238-277 CFM @ .500" lift. The draw back is the intake manifold. Because of the VE's intake manifold ( even the SR16VE N1) we get a low pressure area forming in the middle of the intake runners because they are a slight reverse taper. So you have to design cams around this "drawback" for them to work and make power. The N1 cams are designed for a 1.6L motor, but with that head design and intake manifold as well. So the best way to start with a drop in cam is with the N1 profile and actually modify it from a short stroke/ long rod motor setup ( 68.7mm, 144.6mm rod 2.10 R/S) to a long stroke short rod setup ( 86mm, 136mm rod 1.58 R/S). Because the piston Dwell time is higher on a short stroke motor, the valve timing events are different for max performance operation at high RPM compared to a Long stroke motor with higher piston speed. Thus why you need to tweak the cam gears on N1's to get the most power out of them. I do agree with the stock P12 SR20VE Low cam lobes for starters with any new cam design at this point because they have short duration and high lift for great cylinder fill and high cylinder pressures. N1 Cams do have the potential to make a lot of power on a higher RPM motor with the right cylinder head setup, but it still comes down to the right intake manifold".

    "1/4, 2/3 pairing is actually mainly to keep exhaust temps constant in the manifold for even heat expansion as well as keeping the exhaust pulses constant for fast cat warm up. For performance, a 4-2-1 needs to be 1,2 or 1,3 and 2,4 or 3,4. This is for optimal scavenging. You only gain the maximum benefits of this type setup if the header length is correct. if it is too long or too short you will loose a lot of power".

    "Pairing the cylinders correctly is critical for scavenging. Of all the headers I build, I RARELY have a 4-2-1 header that makes more power than a CORRECTLY WELL BUILT 4-1. The design of the header is highly influenced on the size of the camshafts, the amount of overlap, the exhaust valve opening, the R/S ratio, B/S ratio, the Piston speed over the RPM range of the powerband the header is designed for, exhaust valve size, flow and a few other complicated ones".


    "Coatings are great, There are 3 main coatings that you can do to the piston. The ceramic coating on top is great for keeping heat out of the piston, great for Turbo or Nitrous applications. Also a teflon coating on the piston ring lands and skirts. Most companies dont do this much other than one or two. The last coating is a sort of teflon coating on the bottom of the piston. This helps keep oil from sticking to the piston. This is also a great coating to get done to the crank and rods as well."

    "On stock motors, using an aluminum crank pulley is a gamble. When you remove the dampening abilities then the harmonics get transferred across the crank and can actually loosen the rod bolts. You can sustain high rpm without a crank damper, but that is very dependent on how well the complete assembly is balanced as well as how well the motor is tuned. Detonation, pre ignition, are other factors that affect crank vibration. When building a motor for longevity it is always wise to keep a damper on the crank. If you have a very high HP motor, you may want a larger front crank damper because of the higher forces acting on the crank."

    The biggest problem is a large crank throw. When the rod journals are far from the crank center line you get much more rotational flex between each crank shaft arm. Rotational flex between each crank shaft arm is the problem harmonic dampers try to remedy.High torque creates high crank harmonics, not high horse power.
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    "stock sr20ve motors really are not going to make much over 200whp easily. The Head and maybe the intake manifold just does not flow above 7500rpm. I have tried 5 difference headers 4 sets of cams, tuning for hours on end, changing MAF sensors, and from about 7300rpm+ there really isnt much change. The stock Head just doesnt flow enough for any more power.

    I honestly think that a stock sr20ve motor with bolt ons will be limited to N1 cams, and an AEBS type header. If you want more power and more RPMS you will need to build the motor, plain and simple.

    Here are a few reasons on why these motors are "interesting"

    I have a header with 23" primaries and it makes more midrange than the 26", and 30" headers. i'm talking from 4000rpm+. and a noticable amount. Why? im not sure.

    also, I have a set of larger 290+ deg cams that make more mid than stock sr20ve cams and 284 deg ones like N1's. i'm still not sure why though.''

    "I think anything larger than 288-290 deg adv and 12.0-12.2 lift will be a waste on a stock motor. I will probobly try something smaller than the N1 cam in duration but a little more area and see how that goes."

    " at +7in, -6.5ex is exactly where the valves touch the pistons with a stock 2.0ve bottom end. thats with n1 cams. +5, -5 leaves about 0.041 ex clearance and 0.058 in clearance"

    "i ran stock ignition to 10,500rpm with boost"

    "typically, SR's and VE's like to see about 100 deg IN and about 105 EX C/L.

    N1 cams are at 104 and 110 and work well drop in.
    std VE are at 104 IN and 114 EX. you can gain a few WHP by retarding the EX cam on the std ve cams.

    the N1's work best at about +4 -4 - +5 -5 give or take, that puts them to about 99-100 deg IN and 105-106 DEG EX."

    "putting a girdle in a ve will also cost a loss of HP.this has been tested by me, SR20Turbofreak and by many Nissan racers. You will loose about 5-7 WHP when putting the girdle back in the motor. I only do this when turboing or using NOS on the VE."
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    "A lot of valve spring resonance and surge has to do with the valve opening and closing rate. also known as valve velocity. Take for example N1 cams. nissan rates these at 288* 12.0mm lift and the std sr20ve cams 264* 10.7mm lift. this is nissans rated numbers at .016" lift. If you degree these cams in or run them in a cam doctor you will see that the N1's do have more lift but the valve opens much slower than the 20ve cams. these cams create different harmonics and because of this N1 cams are safe on stock valve springs to well over 8000rpm and sr20ve cams will usually bend valves and or start to float by 8000rpms.

    the same thing goes for the small lobes. Generally most manufacturers of VVL cams will use a shorter duration and more lift profile to open and close the valve faster at lower RPMs to achieve a higher cylinder fill. Open the intake valve right around the end of the exhaust valve closing for low overlap, pop that valve open fast and close it fast right after TDC so you do not get any fresh air/fuel charge reversion back up the intake port.
    These cam profiles are taken into account when the valve springs are designed but they are not planning on the small lobes being active with the motor @ redline."

    "The N1 intake manifold has better flow abilities as well as atomization than the standard intake manifold. They both lack enough combined flow for much power over 200whp (SAE Give or take).

    Sure you can increase the compression, reduce friction, increase thermal dynamic efficiency and make a lot more power, but when it comes to making power from volumetric efficiency, then yes, the Intake manifold seems to be the factor that will continue to hold back these motors."
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    'I am going to say this on our experience the best combo so far its 184-C IN N1 EX even on a 335whp 92x92 13:1 motor!!'

    "Intake manifold design is more important than header design. That is a fact not an opinion. "

    'Dont even waste time and money on 50mm
    I would try Hayward's 60mm if you want to go ITB route'

    "All that needs to be checked its that the choke on the last Y its 2.25 in then after the you can open it with a cone to whatever your exhaust OD is"

    (about intake manifolds)

    "Tuned lengths of 7.5"-10" for NA, runners of 50mm as the dimensional area of the intake port measure about 48mm. Tapered bell mouths of 52mm and larger depending on taper and plenum.

    bellmouth size (mm) x 2 = TB size needed to support."

    "I have tested on both short and long Xcessive Setups!! The short one making more power @ high rpm than the longer one.
    Short version setup with long intake arm its the best of both worlds!! Making most power and torque!! on All size motors from 2.0L to 2.4L"

    (about tri-y headers)
    "In my my opinion its a good budget header that will perform better than a SSAC type of header!!
    Its not the best!!
    The big tube piping sizes and collectors make more power!!
    That's a fact!! We have tested both on multiple cars with same results!!

    "Runner length will move the peak power in the power band...
    Shorter will move it to upper side or higher rpm for example SR20VE N1 cams and stock IM 9in runners will peak @ 7700 or so.. With a super short runners 5.75in (stock SR20VE lower half) and Xcessive plenum same motor will peak @ 8400
    Short runner will not make more power better flowing manifold will...

    "Runner Length
    Runner length also affects the rpm range where an engine makes the most power. Longer runner lengths have a “ram” effect that helps keep the air moving forward as the intake valves open and shut. When an intake valve opens, there is a short lag before the cylinder starts to pull air through the runner into the combustion chamber. A longer runner helps maintain the inertia of the air column so it will fill the cylinder faster.

    When the intake valve slams shuts, the momentum of the incoming air hits a roadblock, and a pressure wave rushes backwards through the intake port and runner. A longer intake runner tends to keep the air moving in the right direction in spite of the reversionary pressure pulse that is trying to push it backwards.


    Shorter runners, on the other hand, usually flow better at higher engine rpm. Reducing the length of the runners may allow the engine to make more power at the top end, but the trade-off may be a loss of power and torque at lower speeds. When choosing an intake manifold, therefore, the runner length should match the engine rpm range where the engine is built to make the most power. If you are building a low rpm torque motor, you want an intake manifold with longer high velocity runners. On the other hand, if you are building a high revving motor, you will probably want a manifold with shorter runners or runners with a larger cross-sectional area to flow more air."

    "The Flow number of the intake manifold itself is not completely useful as it can be somewhat deceiving. The intake manifold alters the flow characteristics of the cylinder head because it directs the flow of the air into and through the port.

    I do have one piece of advice though. It appears that the intake runners are perpendicular to the intake manifold flange. The runners should be at the same included angle as the intake ports are in the head to keep the direction of the intake flow continuous without having to suddenly change directions. If you flowed the intake manifold on the cylinder head where the air had to suddenly change direction turning into the intake port, no matter how slightly, you will have a slight loss in velocity, pressure, and lose flow as well".
    Last edited by sss4me; 31-07-2016 at 05:39 PM.
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    interesting info, thanks for sharing.

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    SR20

    86mm crank
    136.30mm rod
    1.58:1 R/S

    piston speed @
    8000rpm 4515fpm
    10,000rpm 5643fpm

    SR16

    68.7mm crank
    144.95mm rod
    2.11 R/S ratio.

    piston speed@
    8000rpm 3606fpm
    10,000rpm 4508fpm

    Average piston speed increases proportionally with stroke.
    Piston acceleration and deceleration from TDC/BDC where piston speed is highest changes in relation to the R/S ratio on its speed towards and away from the top or bottom of the stroke.

    lower R/S ratio motors make more power
    higher R/S motors have higher longevity (generally)

    'As for the intake port length, they are 4.85" centerline. No guessing here because I made a mold and measured.'

    ''Fast acting intake cams suck on the VE because of the poor intake runner velocity (said by kelford and Chuck to me at different points over the last 3 weeks) This is especially true with the N1 manifolds (again Kelford's and Chucks words)''
    Last edited by sss4me; 21-08-2016 at 10:17 PM.
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    "Did some flow testing today . Take note guys ��. Stock vvl head . Intake only . I did 3 tests . One with head only , one with the p11 lower intake and one with complete intake .
    Lift / head / w low int /whole int
    0.100 70 69 69
    0.200 141 138 135
    0.300 212 206 196
    0.400 253 244 228
    0.500 262 249 233
    So as you can see there is alot of restriction on stock intake system . Not so bad on the lower int only . So ported these could work well . As you can see lower lift flow doesnt get much affected by the stock int its when the lift start to get higher that its becoming a big restricion . All my test were done with radius entrance and around 28inch of water . Please its just info i did on my flow bench . I dont want to here my sister has a friend that has a boyfriend that flowed my head and it was different ��. There are "happy" benches around but thats not important . Most important is what different it makes on the same bench . Supposely every bench should be calibrated the same but its not always the case ."

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    sss4me's Avatar
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    The DE's rod bearings are 17mm wide, the GTiR is 19mm wide. You do not realy want the wider bearing in a high rpm motor. The wider bearing has more load carrying capacity, however, at the expense of a higher gross friction component and consequently higher heat generation. Bigger is not always better, depends on the application.
    If you assume the lighter flywheel and rotating assembly is perfectly balanced then the mean axial and radial 'g' loadings CAN be less on the crankshaft. However the rate of acceleration of the crank will go up and the gas effect on the cylinders CAN create more pronounced eccentric movement of the crank journals relative to the bearing and crank axis at higher frequencies.
    This is ALL speculative as to answer these questions requires either extensive modelling and or testing.
    Remember that in an OEM's motor the key is longevity and economy with power usually being way down in the order of priorities. This is why most of the times you look at the motor with an eye towards mods, you say, WOW why the hell is that so big and heavy.

    My personal theory on the SR's rod bearigns are:

    1-Not sufficent crush on the big end cap to bearing interface.
    2-Too much reliance on the bearing locks as aresult of 1.
    3-Short rod ratio pronounces piston to bore side load which in turn is supported by the geometrically opposite side of the big end of the rod.
    4-Insufficient oil flow to the rod journals with the narrow (DE) oil pump.
    5-High frequency, low amplitude, crankshaft rod journal torsional vibration pronounced by the removal of the torsional vibration absorbing OEM inertia ring pulley.
    This can be as much as 0.3deg of amplitude at the 7th order vibrations at ~3000rpm, based on actual 4 cylinder tests and modelling. Thats 0.3deg (0.054") at the surface of the # 1 main journal. Translate that to the Rod Journal and you can see as much as 0.008" of amplitude on the bearing journal center (assuming there is no movement between the crank journal centerlines........which there is).

    Other tests have shown that the Counterweight center of gravity and actually different weight counterweights (on a 4 cyl crank) yield far better dynamic balance than the "eye" pleasing perfectly symetrical 8 counterweight crank.
    These studies were initiated by the NASCAR guys who had perfect correlations of wear patterns on two specific main bearings, regardless of bearing type, oiling, brand etc.
    The original Porsche 928 V8 had a simillar problem, traced back to the inlet manifold design..........same problem as on a 4 cyl where #3 and #4 fire sequentially......the low pressure on the inlet of one cylinder (because one right next to it just sucked all the air) alters the in-chamber pressure at TDC on the next adjacent cylinder..........the combusted "gas effect" translated to wierd behavior on the crank journals of the two. They cured it by changing the configuration of the inlet manifold.

    SRs like to kill #3 Main right, 3 fires before 4. 4 is starving for air as 3 just sucked the air at the entrance to the port runner. Now 4 fires, 3 is on ex stroke and has the highest rod loading in tension as it is pushing gas through an open system. 4 completes the combustion stroke while 2 has been in compression. 3 and 2 are sharing the same main journal (#3) and has a compressive load on one side (2) and a tensile load on the other (3). The effect is quite possibly detrimental to the #3 Main Bearing.
    Only guessing as it's hard to prove on the SR. Been seen and proven elsewhere though.
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    i asked the question to pipemax 398's owner,larry, what he thought would be the difference between an intake designed for the 3rd resonate (say 5" runners) to one designed for the 2nd resonate (say 10" runners). he response was (based on my findings) pretty spot on. he says (of the 2nd harmonic)..

    1.going to make more Low to Mid-Range Torque + highest Peak TQ
    2.but might not make as much Peak HP as the 3rd Harmonic
    3.HP will fall off quicker after Peak HP RPM point with 2nd Harmonic
    4.the 3rd Harmonic should give overall best combination of Peak TQ to Peak HP

    in my case, less torque 3-6.5k (noticeable), same power ( may be developing reasons behind this though ) hp does indeed fall off quicker ( result of hampered airflow though the longer runners), and the peak torque rpm has increased from 5.3k to 6k, and pretty flat til 8k, where the peak rpm hp point was.

    "Intake length side effects are very different from Exhaust lengths,
    very seldom will an Intake length half-way between 2 Harmonics cause a "dip or valley" in Power Curve,
    and typically increasing Intake lengths make more Torque, but sign-off earlier"
    Last edited by sss4me; 13-07-2017 at 06:55 PM.
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    sss4me's Avatar
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    Just want to share some more flow testing done on a stock ve head .
    We want to compare the stock intake with a gato intake . But before we need to flow the head only to see how much cfm it looses with the intake manifolds on and then to compare both manifolds . This head flows the best compared to all the others i have flowed . So not all heads flow the same . The others flow max 262 on MY bench @0.500 lift . Flow benches vary a lot . I could remove and put it back and it would flow exactly the same . So if i do any change and it gained 5 cfm thats a true 5 cfm gain . Ok now for the good part .

    Lift Head St int Gato int
    0.100 78 76 78
    0.200 154 147 151
    0.300 222 204 218
    0.400 259 229 251
    0.500 269 235 259

    So as you can see , stock intake sucks . And it would need heavy porting and and cutting of the plenum to make it flow better . Which would still not flow what the gato flow . If you want to do something other then gato then do the lower intake with aftermarket plenum . The lower intake doesn't lose a lot of flow compared to the complete intake .

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    quality is remembered long after price is forgotten

  12. #11
    sss4me's Avatar
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    There are 2 main ways of making power, given base identical motor specs.
    1. raise the motors volumetric efficiency.
    2. raise the motors max hp rpm point.

    There is a ton of things to do to improve volume efficiency (ve). improved cams, improved intake manifolds, improved headers, balancing/blueprinting components, lightening components, thermo coating components,superior engine management, better fuels,higher compression, and the list goes on, right down to sneaky stuff like skinnier piston rings.

    Raising the max hp rpm point is limited somewhat by available cam choice. some factory options including n1, and kelford or franklin in aftermarket.

    N1 cams are the default option. These long duration cams have been used by everyone. great for a stock, bolt on, or allmotor. Main difference between them in those different motors is the vvl engagement point. Stock/bolt will work best around 5k, allmotor about 6k.

    With a stock motor, they will raise the max hp rpm point to around the 7.4k. Bolt on around the 8k mark, with those motors long runnered oem manifold. Put on a good short runnered intake manifold, sacrifice some low and mid range power and torque, and they will raise the point to 8.4k-8.7k. they work well with stock heads and compression.

    kelford's popular ve cams are the 184c and 184c4 cms. these feature tighter centrelines and much higher lift, bigger low lobes, less overall duration when measured the same as n1 cams (288 N1 vrs 275 184C, both measured @ 0.016") but greater duration @0.05" lift (258 kelford intake vrs 250 n1 intake). n1's have a very gentle ramp angle, where as both kelford and franklin 118D/E have more aggressive ramps.

    so to some real world examples of what i'm talking about.
    my first dyno with n1 cams and 9 1/4'' runnered intake manifold.



    8k max hp rpm point. it held power peak to 8.3k with a good headers i had, and was still up there at 9k. main thing i dont like was that dip between the low cams running out, and the big cams coming on (5800-6200rpm).

    Then, i changed to the 184c's. the kelford's improved the low and mid range performance (to me significantly, it turned into a torque monster)...right until 7k, then shock horror (with that long intake manifold and less duration), the max rpm hp point was now 7k (the headers extended that to 8k).



    Trent (tuner, chequered tuning) said to me at the time "the cams are out at 7k". years later, looking back, i realise that i'd seen this happen before, to a guy in NZ, with a similar long manifold.



    A few american's (jamie marsh for one) have seen big numbers with the kelfords, running shorter runnered intakes, or itb's. these shorter runners help the kelfords peak later in the rev range.

    6" custom intake



    5.5" intake with 184c intake , n1 exhaust



    The kelfords are a great cam, but their not to be taken lightly. Headwork,compression,springs and retainers are needed, and a shorter runnered bigger diameter intake manifold is (imo) needed to compliment as well.

    Franklins 118E cam may be a dark horse worth mentioning if you want to chase some revs. this chart from a 9 1/4'' runnered manifold all motor in nz



    Still going @8700rpm. they will need spring/retainers, and some shimming.

    IMO a cam with 20v lows ( to get rid of the dip that the n1 low cams have) and a smidge more duration and lift than n1's on the big lobe would be ideal for an all motor chasing revs
    Last edited by sss4me; 27-07-2017 at 10:40 PM.
    quality is remembered long after price is forgotten

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    "I have just been reading some posts on a SR forum regarding camshafts and why some aftermarket exhaust cams are made smaller than the intake..where Nissan do not do this.

    Here are a few points of interest (if you are interestsd otherwise pass it on if you can)

    The reason OEM put huge ramps on their cams is noise..you can be .003" out with your tappet and the thing will still be quiet (fool proof design)...therefore the low lift duration is huge. If you get ours too loose it will be noisy.
    We design lobes based on experiance and testing, our S184-C cams are basically a N1 spec exhaust with altered ramps and more stable design. At the tappet setting we use it has 310 degrees, we have tried bigger exhausts in 2.0L engines with 13/1 comp, I/R throttles and it just lost midrange so we went back to basic N1 spec on the exhaust, and remenber, the better your port efficiency the less cam you need and the more midrange you make, so this cam is designed for ported big valve heads.
    Our intake cam showed more top end in higher compression modified engine, but I doubt that this cam would be any good in a stock engine.
    Remember, it is an engine, just like any other, it has ports, pistons and a crank that have no idea what badge is on the front of the car, so the people talking about Nissan SR-VE's needing different designs need to re-think that...here are some real basic considerations for cam design.
    The intake duration is mostly designed by dynamic compression ratio required for the intended usage, the intake lift by valve size, the intake centreline by duration, closing point and overlap required.
    The exhaust duration is mostly designed by required overlap, port flow and the ability to evacuate the cylinder at a desired rpm. Exhaust lift by pumping requirments, duration and valve size. Exhaust centreline by overlap required and opening point required."

    "Here is my take on the cam spec, if you look at most of the high performance camshaft with durations over 300, including Honda, there will be stagered specs to them. Meaning the intake will be larger than the exhaust. That is the pattern I have noticed. When the intake gets over 300 degrees in duration the exhaust does not follow. If the intake is below 300 the exhaust will have the same general duration numbers. Guess what, most of the stock nissan camshaft have less than 300 duration and so the intake and exhaust have the same general duration #. Camshaft manufacturer already know that over certain duration on the exhaust you can't get more flow or power. Franklin, Kelford, Toda, Skunk, and Buddy Club can't all be wrong."
    quality is remembered long after price is forgotten

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