Roman Posted June 26, 2019 Share Posted June 26, 2019 Thats hardly fair though! 20vs are never good off the line, because the driver cant see the tree through all of the oil smoke 2 Quote Link to comment Share on other sites More sharing options...
kpr Posted June 26, 2019 Share Posted June 26, 2019 I heard muttering in the pits that the resonant frequency of the 20v's effects the timing gear, resulting in inaccurate time slips. the smoke theory does make more sense 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted June 26, 2019 Share Posted June 26, 2019 4 hours ago, Rhyscar said: Here’s some interesting data about primary tube diameter; This is intereresting to me right now, because it shows how much you can potentially move the powerband around with exhaust side cam timing. So assuming you could move the exhaust cam a full 40deg, which mine cant its only about 20 deg, here is the information from this table put in a graph showing how much you could move the powerband peak at a given tuned rpm range: (only went to 8000rpm because cbf typing it all out) But the trend is that higher the rpm its tuned for the bigger the rpm range is. So if I had a header designed for say 7500rpm I could only spread the peak by probably 5-600rpm with 20 deg of VVTI. But then thats not unsubstantial if its a taper away from that peak on either side. I guess you could also move the pulley a tooth on the cambelt. Will be interesting to see how this relates to some IRL testing in a bit. Heres the data from the table with a colour scale In hindsight stopping my numbers at 8000rpm is dreadful, why even get out of bed for less than that. But also, CBF doing it again so here we are. 3 1 2 Quote Link to comment Share on other sites More sharing options...
Rhyscar Posted June 26, 2019 Share Posted June 26, 2019 Love the graph Dave! In conclusion; you can spread the peak with vvti by 500rpm stepped headers can spread the peak by 500rpm Venturi collectors also spread the effective tuning range. It’s safe to say the higher the rpm the header is tuned for the bigger the returns you’ll get another interesting point made in the book is that you’ll get maximum gains if you tune the headers for a rpm half way between peak torque and peak hp. If all the above factors are combined into one header design surely a 1500-2000rpm ‘powerband’ could easily be achieved. 2 Quote Link to comment Share on other sites More sharing options...
Rhyscar Posted June 26, 2019 Share Posted June 26, 2019 @Roman Dave found this article that claims the effect of variable valve timing when combined with header scavenging waves can be up to 4% https://www.mdpi.com/1996-1073/11/6/1545/htm it discredits the gains as not substantial which I think is incorrect. Another 4% just from correct vvti tuning on 140-150kw is a massive gain! Enjoy 2 Quote Link to comment Share on other sites More sharing options...
Stu Posted June 26, 2019 Share Posted June 26, 2019 So much 20v love Good job I have the best 16v there is... stock bluetop awesomeness! Remember kids, rev til bust! 2 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted June 27, 2019 Share Posted June 27, 2019 from the cam timing testing ive done (need to revisit on dyno) can get pretty aggressive on the overlap, inlet advance and exhaust retard. gain a stack of power everywhere usable under peak, with minimal if any loss in peak power . side effect being power drops fairly fast after peak as can see in my dyno sheets. going the other way it will try hold onto that peak power for another 500rpm or so. Inlet had most effect. exhaust done similar but maybe only half or less effect so yeh pretty much nothing new there ^ . if you have vvti /vvt you can have your cake and eat it too. many years ago i attempted to retrofit a vvt pulley off a 20v onto a 16v, its possible but gave up on the idea. 2 Quote Link to comment Share on other sites More sharing options...
mjrstar Posted June 27, 2019 Share Posted June 27, 2019 Vct is awesome. Fg falcon will do 60 degree swing on intake and exhaust, there is a silly trend going around that you throw ~30 degrees or more overlap (there is a simple overlap table in the ecu) to make 'ghost cams' at idle.. I would like vct on my b18c or give it something in the midrange but may settle for some mild cams because stock(ish) ecu life. 2 Quote Link to comment Share on other sites More sharing options...
UTERUS Posted June 27, 2019 Share Posted June 27, 2019 Hell yea. 2 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted June 29, 2019 Share Posted June 29, 2019 @Truenotch Filter vs no filter. cant remember which one is which, but yeh zero loss @Roman red is my normal cam timing. blue is the inlet cam retarded 8 degrees. had a play with the exhaust cam. advanced it 5 deg, then another 5deg. pretty much no change other than a few bumps here and there. maybe slightly better all round with my normal setup, but seems pretty numb to changes. my normal settings im maxed out on both cams, any further pistons will eat valves i do have a vibration issue with either a wheel or wack axle that screws with the dyno and gives inconsistent results, right up top at around 180k i need to fix. / start running it up in a lower gear. 2 Quote Link to comment Share on other sites More sharing options...
KP_wag Posted May 21, 2020 Share Posted May 21, 2020 Daily driving vibratey sparten interior old cars is the way of the future 2 Quote Link to comment Share on other sites More sharing options...
kpr Posted May 21, 2020 Share Posted May 21, 2020 The cams make it lovely driving anything under 30kph, and the gearing makes it a delight to drive over 80kph 3 Quote Link to comment Share on other sites More sharing options...
KP_wag Posted May 21, 2020 Share Posted May 21, 2020 At least you can go faster than 80kmh, DDing the BJ 80kmh is getting up there 2 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted September 24, 2020 Share Posted September 24, 2020 Do you have a pre and post intercooler temp sensors to see what difference the intercooler makes? Quote Link to comment Share on other sites More sharing options...
kpr Posted September 24, 2020 Share Posted September 24, 2020 wrong thread yo. but close enough. only got post iat sensor. The temps were never really an issue, china intercooler cooled good. just doesn't flow enough 1 1 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted September 24, 2020 Share Posted September 24, 2020 Oops haha. Was the first thread I saw. Quote Link to comment Share on other sites More sharing options...
Dudley Posted March 26, 2022 Share Posted March 26, 2022 Super 1 Quote Link to comment Share on other sites More sharing options...
deankdx Posted March 26, 2022 Share Posted March 26, 2022 now i have 2 more threads to read looking forward to the testing videos! 1 Quote Link to comment Share on other sites More sharing options...
nick_m Posted March 28, 2022 Share Posted March 28, 2022 throughly approve. vvti would be epic Quote Link to comment Share on other sites More sharing options...
shrike Posted April 6, 2022 Share Posted April 6, 2022 What did you have to do to get the vvti pulley to work on the 4age? did it just bolt upto the cam? assuming you had to add an actuator etc to turn it on and off? Very cool, any benefit in setting up exhaust side control Beams blacktop (Altezza) have intake and exhaust right? did the 2jz setup make more sense/fit better then the beams setup? Quote Link to comment Share on other sites More sharing options...
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