Jump to content
SAU Community

Recommended Posts

Hey guys yes VCT is turned off it was

Dropping off at hi rpm now it has another kick

He also said that the front pipe an pod are holding it back...

Peak power is more likely to be held back by your fuel system than your front pipe and pod. VCT can be turned off mid way through, so have it on until 5000rpm to boost your torque up to that point (you're definitely missing torque out down there), then turn it off to ensure that it maintains the same high rpm power you are currently seeing.

The reason it feels like a stout kick up high is before its lacking the torque the motor could be making up until 5000rpm, the engine is designed to rely on VCT to have a good spread of torque - you're potentially missing out on ~10% of the torque you COULD be making at 4000rpm, which you'd definitely know about.

Link to comment
https://www.sau.com.au/forums/topic/375658-yeww/page/2/#findComment-5993328
Share on other sites

Was it fully tuned with it both engaged and disengaged? Dynoing with VCT off in areas where the engine is tuned with it on - or vice-versa, means that the tune will be off for the current state which could give a misleading indication of where the curve intersection point should be in an ideal situation.

Link to comment
https://www.sau.com.au/forums/topic/375658-yeww/page/2/#findComment-5993425
Share on other sites

Was it fully tuned with it both engaged and disengaged? Dynoing with VCT off in areas where the engine is tuned with it on - or vice-versa, means that the tune will be off for the current state which could give a misleading indication of where the curve intersection point should be in an ideal situation.

When you say fully tuned, do you mean an individual tune either way? The comparison was done on mine with only one tune, the current one. I lost 20rwhp in the middle from having it off. It made no difference above 3900 so that's where we left it.

Also, DVS JEZ mr nissan would have worked out the vct switching point based on a car running 5 to 7 psi through a stock turbo with an entirely stock car. Its possible that when a car gets everything on it swapped over from the computer to the tailpipe that it would have a different vct switching point.

Link to comment
https://www.sau.com.au/forums/topic/375658-yeww/page/2/#findComment-5994661
Share on other sites

Mr nissan would have spent alot of time working out the best VTC switching point

Probably, but when we are tuning non-factory setups with non-factory ECUs we don't have the luxury of using whatever rules Nissan implemented - nor can we be assured that they are calibrated to perfectly match whatever deviation we have from what they designed in the first place. We can't even be sure that they had our best interests (ie, powah!!) at heart, I know of other manufacturers definitely making decisions on this kind of thing based partly on how "exciting" it feels (often at odds to the outright best performing), emmissions, fuel consumption as well.

Link to comment
https://www.sau.com.au/forums/topic/375658-yeww/page/2/#findComment-5994746
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Latest Posts

    • I hadn't thought about the variable power steering assist. Presumably, it will always be the same level of assist as you get in an S14. The R32/3/4 are either helliishly heavy (at low speeds) if the solenoid is not powered at all, or hellishly too light (at high speed) if it is powered all the time. I presume that it is PWM controlled on those cars. I hadn't thought about the S cars not having variable assist. ugh. What crappy plebby cars they must be!  
    • Hmm yeah that is a good point. It looks like it'll just bolt in with no real issue besides maybe the bushings being different. My other concern was that 2 pin plug that I assume is used in some way to control the rack solenoid depending on the speed signal from the ecu. The DMAX rack doesn't even have that plug though so, don't think it'll matter. Might just order the rack and see how it goes. Will update this when I figure something out
    • I'd say it's a fair bet that the feed and return fluid lines will be in different enough spots that you would need to come up with a way to cut the originals short and adapt with new hard line adaption or braided teflon hoses or somesuch. But really, you have the car, you have the photos of the DMAX rack - you should be able to go out there and see for yourself whether they're in the same or different spots.
    • I've been doing some looking around and honestly was just considering throwing a new rack at it. I saw that the dmax silvia rack bolts up into the 33 with the silvia bushings but not sure if the high pressure lines will sit in the correct spot. I believe other version of the 33 rack are the same/similar to the racks that can be opened up without as much fuss so I assume the dmax rack would fit but any ideas?
    • I've never played with one, but I would expect that you are correct. That slot looks like it is intended to be used to unscrew the end, and the flats on the body would be better than grabbing it around the round bit with a pipe wrench. So, yeah, probably unscrews. You'll probably have to make a tool to drive in that slot.
×
×
  • Create New...