gt-ahhh!

im not worried about running more boost. id happily run 25psi if it made more powah. the set gain of 15/15.5 psi setting is when the ebc starts to regulate boost, according to the greddy manual. and they recommend setting this for 2-3 psi below desired pressure. yeah i can wind it up to maybe 17 or such, ill try it tomorrow. would 1 psi at 3500-4500 really make much difference? cant hurt i guess!

i wound the gain up from 19% to 30% (the max setting is 35%), and the start gain from 15psi to 15.5psi. it didnt make any difference as far as the seat of my pants is concerned. i still think its lacking power below 5000rpm. will look at the other issues.

what is an op6? yeah i reckon the turbo comes on pretty well, its just that the pull is gradual when it does!

yeh its pretty close to its limit. they wound more boost in but it wasnt making any more power so no point. the dyno graph actually shows it makes the same peak power at 15psi, but less across the range obviously. no the cats not piped. my logic being if i ever get done for it ill just say it broke. not sure if theyd ever pull it off and notice a pipe though...

thanks SKYPER interesting reading. the cam gear adjustment graph looks promising.

haha ash you really know everything dont you! so you reckon i havent got extra top end at all? im just basing the 240rwkw figure on the dyno graphs ive seen. my main concern is with the nature of the power curve, being too top heavy. i will def have to go talk to the tuner about the points everyone has raised. in regards to the exhaust, its got a 3in split dump. a 3in cat that had an unfortunate incident with a hammer and screwdriver. behind that, i had the centre muffler cut out and its all 3.5in jasma straight through resonator and muffler. i did take it off once for a laugh, but i dont imagine it would be too restrictive haha can resonators get blocked up? i know the mufflers not, i can see through it!

all mine. the green run was the best, but the timing was wound back a touch to be street safe, which is the blue run. the red run, and red boost curve is for the low boost mode on my ebc.

all these things were checked, or should have been, as it was professionally tuned. as for afr's, i havent actually seen them myself, so i cant comment. but that might be worth a look. the main reason i suspect, and have been advised, the cams are non-standard is because of the top end. generally that turbo wont make much over 240rwkw peak power. and since its designed to be close to stock response, it shouldnt be making more and more power past redline like mine does lol. before i made this topic i looked up dyno curves of similar setups and they were all making more midrange but less top end than me! i cant think of anything usual done to the motor, its a stock head gasket... so normal comp. other mods - injectors, ebc, whole exhaust, intake manifold, fmic, bov, map sensor ecu, splitfires... all the usual stuff.

all good points. the vct is def working. i know this because the electrical socket broke not long ago, and it was VERY noticeable! boost, 16psi @ 3500rpm. so thats pretty good id reckon! its a smooth curve between 16-18psi across the range. i dont know that much about cams, but yes my tuner did describe it as a poncam.

it has an electronic boost controller... so i wonder if fiddling with that could help?

i don't think they had obvious markings on them mate.

hey all, ive got an r33 rb25det with all the usual mods for 250rwkw. the turbo is a gcg hi-flow. it chucks out unusually high kw in the top end, and keeps making power well past the redline, but unfortunately this is at the expense of midrange, which is down approx 20-30kw compared to similar setups. my tuner and i believe the rb25 head i installed must have a set of camshafts for the dyno curve to behave this way. (see attachment) this is all fine in a straight line, but on the street it can be very sluggish below 70kmh (unless you try to crash it into 1st i guess lol) my question is this: would an adjustable ex. cam gear improve this? to what extent? or would i be better off going back to stock/other camshafts? i believe the vct is functioning, and that choosing a cam gear is probably cheaper in terms of labour and tuning? thanks!

hi welcome to sau! what the hell happened to your motor? i have dealt with bad mechanics before, and you end up paying for everything twice, having to undo all their bad work. very painful. good luck with it.

gtr?

HAHA it lived there for about 3 months! it started as a motor in and out... and then i bit off more than i could chew and added a turbo, clutch, split dump, $200 cat (which i then gutted in a fit of rage), ecu and bov. the motor came minus camshafts. but my cams from the blown motor didnt turn in that head. so then i had to find a replacement head, have it machined, new gasket etc. then we had to get all the water and oil lines for the turbo! the old turbo was oil cooled only, so whoever installed it just hacked off all the water feeds. needless to say, genuine nissan cost a mint. and after all that, when the car rolled off the dyno at long last... the wastegate actuator fell off on the way home! and now this vct problem! its been 5 months since my poor baby has been running at 100%. cant wait until i get a gtr and do it right the first time.

thanks nytsky. are you a JEM regular? pretty impressive output from a RB25.

thanks everyone for your help and advice! the people who mentioned vct were right on the ball. the electrical clip for the vct solenoid was broken! its runs much better now, but will obviously have to be re-tuned. i dont know how they didnt notice this on the dyno though...

yes it feels lacking in mid range. big time! i found the problem, the vct electrical clip was broken and disconnected. i replaced that and hello midrange powah! trouble is, they tuned it like that. so i expect they wont mind re-tuning it properly now.

probably standard size. why do you ask?

thanks. i will definitely hit up the tuner after the last few posts. i have no idea whats going on with the timing and vct etc etc. that was the only dyno printout i got. intake pipe is factory item. cooler is hybrid 600x300 with 3in outlets. i thought the cat might have been blocked, so i went for a drive minus the exhaust lol. lots of noise, but no extra power. in regards to air temp, they should be able to check this on the dyno yes? the ecu has air temp correction i believe.

sorry this was a dud reply. but i may as well use it to reanswer the injector question. they were on the plenum/fuel rail/motor when i picked it up second hand. and yeah, nice to have up my sleeve if i ever go for more power.

thanks for your input. yes the timing belt and head gasket were replaced when i put this motor in. so thats a very good point, i will have to ask my tuner about that. the suction pipe is the factory one, clamped onto a z32 afm which is not wired up since im using a map sensor.

they were on the plenum/fuel rail when i bought it second hand. also, yeah just a good upgrade to have up my sleeve.

www.justjap.com www.slidingperformance.com

any help or advice greatly appreciated!