bt20v vvt dyno question???

[slider4life]

hi guys i got my ae86 tuned today again. only problem is at it makes good power till it hits 5500 6000rpm then goes flat looses 10hp then slowly picks back up and makes more power at 7500 on wards. then we decided to turn off vvt via the haltec and it was a nice solid curve to 127hp except it was about 20hp under the line of the vvt run. this said it makes alot beeter mid range power with vvt then without, i just have a dead spot at six. dose any one know what this might be???? i got told it maybe i need longer trumpets as mine are very short????

[timbo]

so on the vvt run it made 147hp?

could it be ignition related? i think the tech guys will probably ask for some more info so maybe you could elaborate on the issue.

[Gunner]

like the fact you just bolted in 272 cams?

[slider4life]

Sorry guys no I had 272 cams in for a while. And when I dissconnect vvt it's 20hp down from 1000 rpm to 6000rpm. And from 6500 to 8000rpm the graphs for both are the same. So the vvt graph is 20hp better till it hits 6000rpm then it dies it is a solid climb on graph then it's as if something that turns off it drops 20hp for 1000rpm then it starts to climb again to 127hp. And no it still makes 127hp with or without vvt just vvt makes heaps better mid range

[Slimer86]

My silver top (Std ecu) made a similar dip in the vacinity of VVT activation/deactivation.
Have a look at the A/F ratio, is it richening up in the area?
This happened to mine, but couldn't do much. (10.5 on mine)

[slider4life]

10.5 thats rich as all hell mine is more in the spot of 13.0 on my one is this too lean???

[Anthony]

is the haltech set to turn the vvt off at 6000? or is it still on til redline (like a lot of ppl incorrectly set it up)?

[slider4life]

ahh im pretty sure it was set at six then got changed to 9000 rpm but didnt make a diffrence.

[pornstrv]

vvt is only to be used in mid range wont change power up top
mine is set a 2200rpm till 6100rpm we found that it works good on the 20v

when it drops just put bit more timing in it

[biggo]

Turn it on and leave it on?

What is it with the "tech" on the end of computer manufuctuares? Fucking usless cunts if u ask me

[Sam-Q]

can you show the dyno curve for us to look at?

[slider4life]

I left it at the shop I will go for a drive and pick it up Monday and post it up thanks guys

[charged]

heres my dyno sheet of my BT that was recently tuned... no real dip
http://www.ae86drivingclub.com.au/dcimages/1/7/8/6/43513.jpg

[slider4life]

charged what mods do you have to your motor do you retain vvt and what computer thanks for that wish my graph looked like this, Who tuned it for you???

[Sam-Q]

mine has a serious dip after 6500 on my ST but that has to be because of my intake resonance

[charged]

charged what mods do you have to your motor do you retain vvt and what computer thanks for that wish my graph looked like this, Who tuned it for you???

The motor runs spool rods with toda pistons for a comp around 13;1, stock cams, stock head cleaned up and 440cc inj running on e85, the ecu is a autronic smc. The tune is a conservative one at the moment but will be getting retuned now the clutch is fixed and has a decent pinion in the diff. I expect a few more kw as there is a ecu interface problem at high rpm limiting rpm about 8300rpm. Adam Allan and Jamie(Frak) did the tune

heres a little vid of it running at Bathurst
ZYKmUvTfYvg

[slider4life]

here is the dyno sheet the purple on is as it is now blue was a run with vvt off

[Gunner]

dont have one with the afr?

[slider4life]

sorry mate i dont but i remeber it being about 13.5 to 14

[pornstrv]

must be somthing with the cams

[slydar]

ant pretty much spelt it out for you. your vvt on/off points are incorrect. the fact that switching it on and off changes the curve alone should tell you that.

[slider4life]

but we tryed it from 1000 to 9000 rpm and it didnt change a thing?????

[FoldKing86]

?Possible the inlet cam gear is buggered or the vvti solenoid itself. Not allowing the oil pressure thru properly??