sr20det VVT cam selection - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

gaz_moose · 12-02-2016, 05:41 AM

I blew my head gasket so am rebuilding my engine/making some improvements.

its the usual suspect bottom end with uprated rods/pistons/ARP's etc..
I plan to use a GTX2867R in .64 trim with some nismo 740's which I hope will see me around the 400hp mark. im aiming for good driveability/response so a nice powerband with little lag.

I plan to fit a set of cams into the equation and was contemplating a set of 256 tomei poncams as they seem to match my goals, ive seen that you guys use JWT cams but they would work out about $300+ more than the tomei's for me which puts me off them. SO.. would the poncams be the best bet for this turbo setup or have I overlooked a different option?

I an going to keep the VVT to help with the midrange so was trying to avoid fitting heavy springs as im under the impression valve stomping springs kill VVT. does anywhere stock new OEM springs or some that are not too savage??..

gaz_moose · 12-02-2016, 01:29 PM

my main concern is that they might be a bit too mild and I should opt for something like the 260 procams or the brian crower cams.

what are peoples thoughts on the crower springs? I don't plan on revving the engine past the stock redline (7200) so would not bother with titanium retainers.

Kingtal0n · 12-10-2016, 02:18 AM

If a street car you want a weak spring and low/stock lift. No 2-step, no t-brake, no rocker stopper, use 6800~ for daily driving and it will never throw a rocker or give you any trouble. You can turn it up for a race/dyno.

The cam for a 7k redline is either 25x or 26x. You use the 25x if you have both stock manifolds, as it will choke a bit up top anyways, while giving you a slight advantage to torque everywhere else, this is recommend for street cars.

To set the VTC you make 2 dyno passes, one with it on, one with it off. Overlay the two graphs and find the switch point.

jr_ss · 12-10-2016, 02:56 AM

The benefit of using JWT cams, especially the S3's, is you do not need to upgrade the valve springs. You have to contact them and let them know you'll be using it in a VTC motor so they can drill the can for it.

By all means, a Tomei/HKS/etc 256 will get you what you want.

gaz_moose · 12-10-2016, 07:55 AM

the car is a trailer queen and gets used for drifting/track work. ive not driven it on the street legally for about 4 years ,so it spends most of its time getting a beating.

im trying to spec it for doing both high revving (7K) fast tracks and low revving technical tracks. so I kind of want to have my cake and eat it and have an engine that performs well at both ends of the spectrum. I see too many guys with massive turbo's struggle at the small tracks because they are off boost.

I have a tubular manifold/elbow/exhaust but stock intake manifold.

although ive never had any rocker trouble in the past 8 years ive beaten on this engine my concern is that the current springs may be getting a little tired. I can get the BC springs for about £100 without retainers but am not sure if they are overkill and will cause me trouble. if I could get new OEM springs or like 10% uprated for £100 then I would opt for those.

jr_ss · 12-10-2016, 08:29 AM

Supertech or Tomei springs are the only spring steel that would find their way into my motor.

Keep the factory exhaust manifold. It retains heat better than a tubular and is good well into the 400's.

12-02-2016, 05:41 AM	#1
gaz_moose Zilvia Member Join Date: Mar 2008 Location: engerland Posts: 242 Trader Rating: (0) Feedback Score: 0 reviews	sr20det VVT cam selection I blew my head gasket so am rebuilding my engine/making some improvements. its the usual suspect bottom end with uprated rods/pistons/ARP's etc.. I plan to use a GTX2867R in .64 trim with some nismo 740's which I hope will see me around the 400hp mark. im aiming for good driveability/response so a nice powerband with little lag. I plan to fit a set of cams into the equation and was contemplating a set of 256 tomei poncams as they seem to match my goals, ive seen that you guys use JWT cams but they would work out about $300+ more than the tomei's for me which puts me off them. SO.. would the poncams be the best bet for this turbo setup or have I overlooked a different option? I an going to keep the VVT to help with the midrange so was trying to avoid fitting heavy springs as im under the impression valve stomping springs kill VVT. does anywhere stock new OEM springs or some that are not too savage??..

12-10-2016, 02:56 AM	#4
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	The benefit of using JWT cams, especially the S3's, is you do not need to upgrade the valve springs. You have to contact them and let them know you'll be using it in a VTC motor so they can drill the can for it. By all means, a Tomei/HKS/etc 256 will get you what you want. __________________ My SR20VET

12-10-2016, 08:29 AM	#6
jr_ss Post Whore! Join Date: Dec 2005 Location: Pa Posts: 6,056 Trader Rating: (34) Feedback Score: 34 reviews	Supertech or Tomei springs are the only spring steel that would find their way into my motor. Keep the factory exhaust manifold. It retains heat better than a tubular and is good well into the 400's. __________________ My SR20VET

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12-02-2016, 01:29 PM	#2
gaz_moose Zilvia Member Join Date: Mar 2008 Location: engerland Posts: 242 Trader Rating: (0) Feedback Score: 0 reviews	my main concern is that they might be a bit too mild and I should opt for something like the 260 procams or the brian crower cams. what are peoples thoughts on the crower springs? I don't plan on revving the engine past the stock redline (7200) so would not bother with titanium retainers.

12-10-2016, 02:18 AM	#3
Kingtal0n Post Whore! Join Date: Jul 2005 Location: South Florida Age: 38 Posts: 4,649 Trader Rating: (17) Feedback Score: 17 reviews	If a street car you want a weak spring and low/stock lift. No 2-step, no t-brake, no rocker stopper, use 6800~ for daily driving and it will never throw a rocker or give you any trouble. You can turn it up for a race/dyno. The cam for a 7k redline is either 25x or 26x. You use the 25x if you have both stock manifolds, as it will choke a bit up top anyways, while giving you a slight advantage to torque everywhere else, this is recommend for street cars. To set the VTC you make 2 dyno passes, one with it on, one with it off. Overlay the two graphs and find the switch point.

12-10-2016, 07:55 AM	#5
gaz_moose Zilvia Member Join Date: Mar 2008 Location: engerland Posts: 242 Trader Rating: (0) Feedback Score: 0 reviews	the car is a trailer queen and gets used for drifting/track work. ive not driven it on the street legally for about 4 years ,so it spends most of its time getting a beating. im trying to spec it for doing both high revving (7K) fast tracks and low revving technical tracks. so I kind of want to have my cake and eat it and have an engine that performs well at both ends of the spectrum. I see too many guys with massive turbo's struggle at the small tracks because they are off boost. I have a tubular manifold/elbow/exhaust but stock intake manifold. although ive never had any rocker trouble in the past 8 years ive beaten on this engine my concern is that the current springs may be getting a little tired. I can get the BC springs for about £100 without retainers but am not sure if they are overkill and will cause me trouble. if I could get new OEM springs or like 10% uprated for £100 then I would opt for those.