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View Full Version : Removing VVTi for Race Engine


daewoo01
09-22-2020, 09:36 AM
Looking into VVTi and cams, and how it works. Wondering if you wouldn't be better just setting a more aggressive static cam timing.

Race specific engine, so always over 4000rpm when VVTi is almost always fully advanced.

I understand for road and performance applications, VVTi is great for emissions, idle, and economy, but is it an unnecessary (and mostly unused due to revs) complication?

xnamerxx
09-22-2020, 02:58 PM
VVTI in my engine advances from 3-5k and is back to 0 by 6k, its provides great power and torque for midrange. I've had it on all of my race engines and its provided big benefits in power even with giant cams.

daewoo01
09-23-2020, 08:54 PM
I've had it on all of my race engines and its provided big benefits in power even with giant cams.

Thanks for that.

I'll admit I know not a lot about tuning. On my SR20DE powered Rally Car I have adjustable cam gears, and was wondering if there was any point in not just doing the same.

One thing I picked up from further reading was the Variable but in VVTi. It isn't a step change, it's a progression.

xnamerxx
09-24-2020, 12:45 AM
Older VVT isn't like newer vvt, so in the case of the SR20 VCT its basically a on off swtich because the resolution was so low because the electronics of the day weren't very sophisticated.
As far as doing cam adjustments, there is benefit, but you'll need to spend sometime on a dyno with a competent tuner who can set it properly.
The only issue I've ever really had is that VVTi is really reliant on oil pressure and the solenoid being sealed, so if you have really heavy valve springs its possible to overpower the actuator at certain RPM's but so far I haven't found that limit yet.

daewoo01
09-29-2020, 08:11 AM
Thanks Man... Just trying to learn about these cars.