VR4 cams vs 61NA cams

[Jazz9]

What do you guys reckon?

VR4 cams or 61NA cams?

i am running mostly vr4 external parts on the 61 - it is a 61NA intake and head on a 61t bottem end.

I might get the 61t head rebuild ( bent valves ) and then put vr4 cams into it .... argh --- too many options....


Glen

 

[JayRome]

N/A cams top out too early....

VR4 cams will give you a better power delivery accross the RPM range...

 

[JAP63]

N/A cams top out too early....

VR4 cams will give you a better power delivery accross the RPM range...

Interesting, top out as in run out of puff earlier?
i know theres always been big debate on this, can you explain a little more? Has anyone heard of putting N/A '63 cams into a VR4 motor, apparently it makes better power...

 

[mrcyborg]

anyone done any searching on 4g61t.com?
i remember some pretty extensive testing done some years ago on this and the different heads and so on.

 

[JayRome]

Interesting, top out as in run out of puff earlier?
i know theres always been big debate on this, can you explain a little more? Has anyone heard of putting N/A '63 cams into a VR4 motor, apparently it makes better power...

basicly i have had both cams in my hi comp (jspec ECU, tri-y's, CAI, cyclone intake, etc)

basicly
N/A Cam: tend to give you a load of torque nere the 3k mark, normal driving in what ever gear and most of the time you sit at 3k so it makes sense. go anything past around 5k and it takes a while to pull to redline. i found it to be alot better on the fuel econ, but really sucked in the power, but you could always compinsate with engine timing and cam gears.

Turbo Cam: tends to give you a long power band, from about 3k onward and tends to pull till about 6k. day to day driving feels good but you can feel a slight lack of power at the same rpm marks as the N/A but feel alot better revving out.

obviously depening on your mods you get very different out come... N/A cams would make sense to make more power, but an even delivery accross the rev range would probably be a prefered option...

 

[JAP63]

Interesting, i thought since an N/A motor has to work to breathe the cams would be pitched a liitle better for the upper rev range

The turbo does get air stuffed in though at mid-range, so they can afford to have a poor mild effect and concentrate on a top end type lobe, as the turbo is making all the mid range torque for the engine any way.

 

[mrcyborg]

yes from what i have read with the na cams they come on a little lower, and matched with a turbo you tend to get a big midrange but it also makes the turbo over work and max out earlier and not as effienct up top.
where as your normal turbo cams are aimed higher, the turbo comes on mid rev range and cams come on later opening up flow to keep turbo going up higher revs.

 

[JayRome]

yes from what i have read with the na cams they come on a little lower, and matched with a turbo you tend to get a big midrange but it also makes the turbo over work and max out earlier and not as effienct up top.
where as your normal turbo cams are aimed higher, the turbo comes on mid rev range and cams come on later opening up flow to keep turbo going up higher revs.

i believe you have it


N/A cams would be good for really twisty cornering, Turbo cams would be good for the long straights...

 

[Jonson]

Well i have a set of N/A 63 cams with gears I'm happy to donate to test.

 

[mrcyborg]

still easiest thing to do would be research, i am quite sure the crazy US guys would have had the answer years ago.
dont take everything they do as gospel though, they do many many crazy stuff too thats probably not needed over here as we have a better range of parts much more easy to get then they do.

 

[OLDIE]

From memory the HG GALLANT GSR NA motor the max hp was at 6000rpm & max torque at 5000rpm so why would the motor run out of puff early ?????????????

 

[CLuTZ]

From memory the HG GALLANT GSR NA motor the max hp was at 6000rpm & max torque at 5000rpm so why would the motor run out of puff early ?????????????

Was that peak power figures though? I drive a 7-bolt N/A and the power band is ridiculous- makes no power after 4500rpm

 

[to4garret]

glen you lazy bugger, you have both sets of cams there, just measure them up

 

[JayRome]

Was that peak power figures though? I drive a 7-bolt N/A and the power band is ridiculous- makes no power after 4500rpm

yup bout the same as my HG GGSR...

 

[cheaterparts]

4G6x DOHC
Listed is the open/close, (duration), cam height, and lift.
Letter= Cam ID mark
Intake
A-26/46 (252) 35.49 9.5mm
B-21/43 (244) 35.20 9.0mm
C-23/57 (260) 35.79 10mm
D-21/51 (252) 35.49 9.5mm
E-16/48 (244) 35.20 9.0mm
F-26/38 (244) 35.20 9.0mm
G-18/62 (260) 35.79 10mm
H-Unassign
I-Unassign
J-21/51 (252) 34.91 8.5mm
K-18/62 (260) 35.38 9.3mm
Exhaust
A-55/9 (244) 35.20 9.0mm
B-Unassign
C-57/15 (252) 35.49 9.5mm
D-54/18 (252) 35.49 9.5mm
E-43/17 (240) 34.91 8.5mm
F-53/07 (240) 34.91 8.5mm
G-63/21 (260) 35.49 9.5mm
H-63/21 (260) 34.91 8.5mm
I-Unassign
J-57/15 (252) 34.91 8.5mm
K-Unassign

this is from the 4g61t site

my guess you would need a C or G grind inlet and a G grind exhaust
as for them being a turbo or NA grind that would make no difference . however for a turbo you would dail them in with more lobe sep which is easy on a TC
with a single cam you you have to grind the lobe sep into the cam where as the TC can be adjusted to suit

 

[SIVART]

I think you should get a hyundai sonata 2.4ltr and then add goodies,

im going to do this to a 94 lantra as soon as the 1.8 packs up,

and if hectors doesnt pick up his C73A 4wd stuff from my houes its going in there also

 

[cbgsr]

i read this a while back and thought stuff it ill find out!

well i just changed the cams for my na 61 and now not really convinced .I had to do a rebuild before it was running a td04 with standard 61na running 14psi ,380cc injectors, ems 4424 made 137kwatw, so now have fully rebuilt top to bottom 61 td05 550cc injectors,vr4 cams,cam gears,bigger dump pipe, hpc and tefflon pistons,reco head etc running 17psi and only whent 147kwatw so the bigger turbo, cams and 3psi only netted me 10kw gain. now in saying that the car has more petential goning on the dyno again this week but im left wondering if the na cams would have been better it sounds good and does go good but im not convinced the cams made a big difference the overlay of before and after shows its laggier but peak power is at the same rpm give or take a couple off hundred rpm will see how we go but might put the 61na back in for a true test

 

[CLuTZ]

were both runs on the same dyno?

 

[Dean]

yeh, clearly something is not right there buddy.
Would be good to see a comparison though, but i dont think thats your issue.

 

[cbgsr]

both tunes on the same dyno and same tuner?