al_r33

Hey people, Just after some advice about my rb25 & what should be done to achieve the best response and power! I have the head off the car getting planed etc & have decided to put in a set of Tomei Poncams Duration: IN, EX 256 Lift: IN,EX 8.5mm, So I was wondering what would be best as I was only going to put a Cam gear on the exhaust side as I wanted to run the VCT with the cams, but I just wanted to know what people are doing are you using an Inlet & Exhaust cam gear & not running VCT or are you running VCT! As I am tyring to find out some of the setting people are using to achieve good power & results Sorry if doesn’t make sense but I think there enough there to get someone opinion Cheers Alan

PM Me the details mate!

Thanks mate! That has just made it easyer!

can you be sure or just from what you remeber? Do you have the spec sheet for them if you have rb25 20tho ones? Cheers

cheers!

What should be 0.1 higher?

Yer but the guy that rebuilt the motor moved to qld & we cant track him down & the bought the pistons.

anyone?

Well does anyone know what brand they could be! & know i was not given a specs sheet when it was rebuilt!.

Hey people, Got my motor rebuilt about 9months and the Piston that were meant to be put in were Arias Forged Pistons 20tho! I have had problems with compression ratio's so the head has been pulled off and on top of the pistons there is this information RA9603X 0.50 RIB 0.10R1 Can anyone shed any light on these as to what specs these pistons are? As we are trying to work out the Current compression ratio of the motor! Any help would be appreciated! Cheers Alan

Thanks for clearing that up mate!

If you run a cam gear on the inlet side on a rb25 with VCT. Will the VCT work or does the Inlet Cam Gear take over??

I would be interested in taking the 33 down the strip with the new setup!

Hey mate, Your car looks good! What power is it making with that GCG Turbo? Al

Yer he told me that he did push it to the point of detonation as he said he physically coulnt dial in anymore boost or timing & then he backed way off! It wouldnt even make more power when he would lean it out! im getting to the point where im nearly over the old skyline!

nar the oil was comin out the oil line for the turbo! plus the car is barly drivable atm eg. wont idel & i allways have to keep the revs up or it goes to stall! but i think that is being cause by a faulty afm or busted ic hose! but i have tacked down the guy who built it & going to talk to him as to why he would build an engine with a compression ratio of 7.5:1.

Basically the mechanic recons that it has a ratio of around 7.5:1 & that the VCT isn’t correct! He spoke to a few guys and they have had the same problem with a rebuilt rb25 with all the mods should have made 300rwkw but made around 180rwkw so the up the ratio to 8.4:1 or 8.5:1 and played around with the vct and cams & stuff like that and put it on the dyno & it made 330rwkw @ the same boost & same tune! So they have suggested to me that we raise the ratio to 8.4:1 or 8.5:1 & muck around with the head & get it back to the dyno for more tuning! Does this sound like a solution or what? Also does anyone know anyone that is making decent power of a ratio of 7.5:1? Cheers Alan

thats the thing i cant do f*ck all because he moved to qld!

i bascally drove the car for 1500km on no boost & no higher than 3500rpm. can anyone suggest how you would fix this sort of problem if the compression is too low?

well that’s the thing the guy who did it knew his sh*t that’s why I found it hard to believe that he built a bad motor! I don’t have a catch can! the exhaust was replaced after the rebuild as with the other parts! the guy who check the cam timing said it was spot on! so I dunno what’s going on with it! Cheers Alan

so does it sound like my motor is stuffed? the car still feels very strong & pulls decent enough even thow its only got a 138rwkw

i dont know why oil started going everywhere as the motor has heaps off\ parts of it atm! the dyno is okk as i took it to another one just to see & they bascailly come up the same! the cams were check and come up fine! if its low compression how do you fix that? Cheers alan and as for the headgasket i was aware that it was a std one! Cheers

Hey people, I recently got my rb25 rebuilt about 5000km ago & we have now found out that there is a very big problem with power output etc. I recently got a PFC installed & the best we could achieve was 138rwkw on .7bar with the following mods forged piston set 20tho gtr rods arp conrod bolt set race series main bearing set bigend bearing set nissan gaskets nissan cam belt pfc fmic 3.5inch full exhaust avcr (.70 Bar) cai stock turbo stock injectors Now the problem is not with the tune as we put it onto the dyno before the pfc went in and the best it got was 111rwkw on stock boost! so the was a gain of 27rwkw at the end with the pfc installed., the tuner said that it could have an extremely high static compression ratio or another issue. so then we thought it was a turbo issue but we pulled it off yesterday & the turbo is fine! which means there something wrong in the motor! we did a leak down test & compression yesterday and these are the results leak down test: this was done with the car not being started in 2weeks so its dead cold! 1 cld: 7% 2 cld: 5% 3 cld: 5% 4 cld: 5% 5 cld: 9% 6 cld: 6% compression test: also done cold 1 cld: 120psi 2 cld: 115psi 3 cld: 125psi 4 cld: 125psi 5 cld: 117psi 6 cld: couldn’t do 6 as oil started going everywhere so the were the results & we still don’t have a clue on what the problem could be! the compression test come up really low but couldn’t that be caused by a low compression ratio? I guess if any one has had this problem or could shed any light on it that would be good. Sorry about the crappy post but im not really mechanically minded! Cheers Alan

Thanks Mate!!!

yer its manual. I got tha turbo off & new turbo goin , 550cc & z32. I will let ya know how it goes but it will be awhile as im going to take it to melb to tune it!