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would like to know what compression a 2 litre ve should have with stock 2.0 cams and a 2 litre ve with sr16 cams. i dont want to know the compression ratio, but want to know what you guys are getting when you do a compression test.
thanks for any info..
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-2005 c230 kompressor.
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I got 225 psi across the board with stock sr20ve cams and same with n1’s.The reason I got the same compression because on a sr20ve when you do compression test its on low lobe, thus same size small lobes .Now with regular sr16ve cams which is slightly smaller cam you should see about same or little more psi but nothing much 1+2 psi ect.The Bigger cam lower compression from what I have seen.
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down here we tested four engines. two with stock 2.0 cams and got 210 on both. both of the cars reun very well. on of them was phil's and he made 178 whp. the other also runs very well. the other two engines that were tested had sr16 cams, and both made in the 230's. one car has 200whp, and the other has 187 whp.
what im tryin to get here is that i think something is wrong with my engine.. so im just tryin to do some comparisons. i did a compression check the other day and got 212 all the way across. and am using 20v cams and a 20v head. i checked my chain and cam timing and everything is dead on. and my bottom end came from an engine that was damn near spotless that i got from andreas. now i know that the 20v engine comes with a higher compression ratio, than what i have right now. and that the 20ve cams are suppost to be big also... but whats goin on?
im just a lillte puzzled roght now.
just some insight... the car has fuji headers, elec. water pump, 3 inch mandrel, wai, 20v intake manifold with N1 throttle body, 20v cams and a standalone. i really dont beleive there is a problem with the tuning, because no matter what we did. with timing or fuel. the car would not pass 189.9. when expected was arond 200-205. the car runs very well, and takes off harder than the rest.. but kinda dies uptop.
212 seems about correct remember you have huge low lobes so thats the reason you car lower that the rest.Are you 100% you didnt skip a tooth? you should be around 200-210 whp for sure with these mod's.Did you do a leakdown ?compression test don't tell everything. Sometimes you can have a slightly bent valve or bad seal and you can't tell by just looking.Just throwing idea's around not saying you motor has bent valve but you never know.
Actually, depending on the lobe seperation angles and the amount of overlap(if the same as a 20VE cams), he should be craming the same if not more air into the engine regardless of low lobe or high lobe since its a 20V cam and more agressive. As you know more air is compressed so more HP thats why we get cams.
Actually, depending on the lobe seperation angles and the amount of overlap(if the same as a 20VE cams), he should be craming the same if not more air into the engine regardless of low lobe or high lobe since its a 20V cam and more agressive. As you know more air is compressed so more HP thats why we get cams.
Sorry for the off topic but.True but at the end of the day the bigger cam means less static compression.Yes you get more air but it hold open longer (overlap) letting air excape that's why the the static compression end up to be less. example Quote from SR20turbofreak". These cams are going to be used for a big turbo, high rpm drag setup. I lost some power due to the extra duration, compression dropped 30psi from 210 to 180 after installing these cams. I'm going to adjust cam gears and see what she does. Top end power is looking better and has a better curve." as you see big cam means less static compression.
Sorry for the off topic but.True but at the end of the day the bigger cam means less static compression.Yes you get more air but it hold open longer (overlap) letting air excape that's why the the static compression end up to be less. example Quote from SR20turbofreak". These cams are going to be used for a big turbo, high rpm drag setup. I lost some power due to the extra duration, compression dropped 30psi from 210 to 180 after installing these cams. I'm going to adjust cam gears and see what she does. Top end power is looking better and has a better curve." as you see big cam means less static compression.
that is exactly what i was thinking...because of the big lobes on the bottom, is why i am getting such lower compression numbers when compared to motors with stock 2.0 cams and sr16 cams. but the car pulls out harder than them on the bottom. but up top it dies out. so say i play with my cam gears and change the angle of the cam lobe...the car will pick up static compression when doing a comp test. and make the numbers jump higher. but the car will then loose down low and gain in peak hp's.. is this correct. if so then the 20v's high lobe is pretty big. almost that of a N1's, it will gain almost N1 hp gains? correct?
THe lobe seperation angle for the 20VE cam on the intake is 110 and the exhaust is 122 and the 20V is 114 and 106 respectively. In anycase, the 20V cams have more duration yet open later on the intake and earlier on the exhaust. Less air should be flowing out cause of the tighter lobe seperation angle. Meaning less overlap and less air lossed. Check this thread on honda-tech where this guy tighened up his lobe centers and gained 19psi...175-194. http://www.honda-tech.com/zerothread?id=996451
if what everyone is saying is correct wich i dont doubt anything kesi says. then yeah your statement would make complete sence. by playing with the cam gears youll be playing with the power band and can choose were you want peak whp.
have u spoken to dre about it. does he feel when he had 20ve's that it fell off up top ?
i dont think adreas ever had the car running with the 20v cams. i belive he has been running the N1's from start up. comparing my dyno sheet with my a couple others i am almost ten hp's higher under 5 grand, and then they match or pass mine around 6500, maybe i should try and switch it around by playing with the gears.
Sorry for going off topic but I edited my post twice cause I second guessed myself. But after looking over my old stuff... I feel confident in saying Kesi's assertions dont apply in this case. This is how where I get me info from:
TERMINOLOGY
Just to explain a few terminologies
Note that all reference to degrees is with respect to No.1 cylinder
ATDC - After Top Dead Centre (Top Dead Centre is when No. 1 Pistion is at the very top - corresponds to yellow mark on crank pulley in line with the pointer
BTDC - Before Top Dead Centre
ABDC - After Bottom Dead Centre.
BBDC - Before Bottom Dead Centre.
CAM OPENING AND CLOSING SEQUENCE
In a four stroke engine - the engine goes through two complete revolutions (360 x 2).
REVOLUTION 1 – The piston is at TDC. At the start of the first revolution the intake cam has just opened, and as the piston goes down, air/fuel is drawn in to the cylinder, the piston reaches the bottom (BDC and starts to come back up -then as the piston is coming up the intake valve closes. The compression of the air begins (as the exhaust valve is also closed at this time), and just before the piston get to the top the spark plugs fires, and the mixture starts burning ( this is usually about 15 BTDC ignition timing at idle).
REVOLUTION 2 - Now the second revolution starts, the air/fuel mixture is burning and this is the power stroke where the piston is being pushed down by combustion. Before piston reaches the bottom, the exhaust cam starts opening, once the piston reaches the bottom and starts coming back up with the exhaust valve open - the spent gases are pushed out of the cylinder. Now the cycle starts all over again – i.e Revolution 1 start over again at the end of Revolution 2. The exhaust cam only closes after Revolution 2 finishes, and after the start of Revolution 1, but the intake valve opens slightly before the end of Revolution 2, stays open through the beginning of Revolution 1. This is where cam overlap happens. Therefore for a short period of time the intake cam and the exhaust cam are simultabneously open.
INTAKE CAM TIMING
Cam intake centreline is where you will normally have the maximum lift (and it is generally halfway through the duration of the cam).
For example, the Tomei intake cam is of 260 duration, and if it is installed at the recommended intake cam centreline of 110ATDC then :-
The intake cam will start opening at approx: 110 ATDC - (260/2) = 110 ATDC - 130 degrees = 20 BTDC (Revolution 1)
Maxuimum lift will be at approx 110 ATDC – Revolution 1 (ie valve fully open)
Likewise this intake cam will close at 110ATDC + (260/2) = 110 +130 = 240 ATDC – Revolution 1 (or 60 ABDC)
Advancing the cam means that the cam centreline will be less than 110ATDC (i.e the cam starts opening sooner than recommended). E.g. if the intake cam was advanced 5 degress say, then intake cam centreline is now at 105 ATDC (cam will start opening at 25BTDC and will close at 235 ATDC).
Retarding the intake cam means vice versa. Cam centreline is now more than 110 ATDC (e.g 115 ATDC cam centreline if the cam was retarded 5 degrees, cam will start opening at 15BTDC and will close at 245 ATDC.
Advancing the intake cam means that the cam closes more open at TDC, hence there is a limit to which intake cam can be advanced before valve/piston interference occurs
EXHAUST CAM TIMING.
Likewise the Tomei exhaust cam is of 260 duration, and if it is installed at the recommended exhaust centreline of 64 ABDC (Revolution 2) then :-
The exhaust cam will start opening at approx: 64 ABDC - (260/2) = 66 BBDC (Revolution 2)
Max lift will be at 64 ABDC (Revolution 2)
The exhaust cam will close at approx: 64 ABDC + (260/2) = 14 ATDC (Revolution 1)
Advancing the exhaust cam will mean the exhaust cam centreline will now be less than 64 ABTC (e,g advancing by 5 degrees – 59 ABDC). Opening is now 61BBDC and closing 9 ATDC (Revolution 1)
Retarding the exhaust cam will mean that the exhaust cam centreline will now be more than 64 ABTD (e.g retarding by 5 degrees will make it 69 ABDC). Opening is now 71BBDC and closing 19 ATDC (Revolution 1)
Also note that when exhaust cam is retarded it closes at 19 ATDC (instead of 14 ATDC) – i.e the exhaust valve is now open more at TDC. If the exhaust cam is retarded too much (generally over 7-10 degrees then there is the chance of exhaust valve to piston contact.
CAM LOBE CENTRES AND CAM OVERLAP
Many cam manufactures quote the cam lobe centreline in addition to cam duration and max lift.
Cam lobe centres value indicate how many degrees separate the intake valve maximum opening to the exhaust valve maximum opening position. This is normally expressed as half the actual degrees.
For the Tomei cams, the cam lobe centreline can be calcalated as follows. Intake valve maximum opening (intake cam centreline) = 110 ATDC, Revolution 1. Exhaust valve maximum opening (exhaust cam centreline) = 64 ABDC, Revolution 2. The Separation angle = (180 –64) + 110 = 226 degrees. The cam lobe centre value is 226/2 = 113 degrees.
If the lobe centre value decreases then the cams are coming closer together (e.g 105 lobe centre means that the separation angle btw the intake and exhaust cam centrelines is now 210 degrees). As the lobe centre value decrease the overlap increases – as the cams are closer together, and vice versa
The cam overlap for the Tomei can also be worked out ( from the above recommended installed positions) The intake cam starts opening 20 BDTC (Revolution 2), and the exhaust cam only closes 14 ATDC (Revolution 1). Hence there is an overlap of 14 + 20 = 34 degrees.
POSIBLE CAM TIMING COMBINATIONS AND RESULTS
Normally for billet cams from reputed aftermarket companies, adjustable camgears are not strictly necessary as they have been designed to install in the recommended centrelines with the stock camgears. Adjustable cam gears are needed when the cams need to be advanced or retarded from the stock positions (to customise the set-up).
Idle quality is normally affected by overlap. Lesser the overlap the better the idle, but top end power is sacrificed. More overlap (within boundaries) will make for a rougher idle, but gives better top end power.
Generally if you advance the intake cam (say 3 degrees), and retard the exhaust cams ( again say 3 degrees)…then overlap between the cams will be increased , idle will be a bit rougher, but will give a fairly good mid range power, without much sacrifices in top end power.
Retarding both cams by 3-4 degress will give good top end power, but at the expense of bottom end. Not best for normal day to day driving
Advancing both cams by 3- 4 degrees, gives good low/midrange at the expense of top end – good for autocorsses, hill climb type events.
i dont think adreas ever had the car running with the 20v cams. i belive he has been running the N1's from start up. comparing my dyno sheet with my a couple others i am almost ten hp's higher under 5 grand, and then they match or pass mine around 6500, maybe i should try and switch it around by playing with the gears.
could it be possible that you have the cam gears in the wrong postion ? or do 20v's have that strong of a bottom end ? but i would think either way the 20v high lobes are much more agressive then 20ve's or 16ve's. but if you are eating em up down low and their passing you up top its deff in the cam gears.
I am with Stratton. But I think you already answered it? If you get really mad lance just send me the valve cover... Maybe that will make it run better. HAHA! Good luck getting things sorted out.
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05 Tacoma 4x4
91 White SE-R built de coming up
im gonna try the settings you have there to start off. i am really believing that this will gain quite a few hps out of my motor. i remeber then i had my type-r... out of all the mods i had to it, adjusting the cam gears was the best power adder. in stock form it netted the car 9 whp.
