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gee..am sure you could read ..why bother posting ?...smh also in mind is the smaller Borg Warner S300SX 83-75 .91AR.

please no comments about using the search ....just need some driver feed back moto is stock except for pistons head bolts and extended sump and oil pump..no cams 3'' exhaust. my 6262bb .63 housing just decided to take a crap (its done 3yrs ) and am interested in something with quick spool up.. i would get full boost 20 psi by 4300 rpm 2nd gear with my old turbo. just looking for 450whp have my eyes on a borgwarner s300sx 9180 ... any feed back would be helpful ..i dont want to try back another precision again... thanks

yea could be shim time..but i have seriously long gears so even bringing down the rev to 7500 rpm i still clock 120mph in 3rd ..that trip to take down that oil pan is a bitc* ...rather lower the rev and use boost to get the hp.... oil pressure isn't all of it once i have a good flow..

am running 20w-50 as am living in the tropics & clearance is about 2 thou.. also running a small oil cooler... am only revving stock 7800rpm so am not in any real danger but i would have been more comfortable with a lil extra space psi to the top.

hey guys .had problems with oil pressure due to bearing clearance change the bearings and now its a lil better. now at start up i usually get around 76psi cold start blip the throttle would get as high as 90+ psi , idle is around 30psi warm hot it 22 psi. now i have no oil mods ,no tomi oil restrictor or head drain bk. the oil pressure shots like this 1000 rpm>>22 psi 2500 rpm>>45psi 3500 rpm>>60psi 4500 rpm>>70psi 5500 rpm>>75psi and stays 75 psi to redline (stock) i notice everyone here has relatively high psi 90+ psi up top , but i notice they also have tomi oil restrictors does that really make such a difference in oil pressure? even the service manual i think recommends u should see around 66psi by 6000rpm am running a n1 pump with replacement billet gears and a custom 8 liter sup with baffles... is it the nature of the pump to free flow at higher rpm ?

UPDATE!!!!!! so guys i have changed the bearings and went a thou thicker ..so clearances by elimination now is about .0016-.0018 and the oil pressure is up like a bitc* ..at start up its bk to 78psi but at a blip of the throttle of around 2500k its up to 100psi n climbing ...when warm it idles at 28-30psi when heated after some pulls it rests about 22-24psi ...at 3k when hot or warm its up to 70 psi at 5k its up 84psi .... when hot after some pulls it goes around 60psi at 3k and 74-78psi at 5k and holds..i havent hit the limiter yet as i see no reason too ,, car pulls hard... have a new problem now..lol... experiencing windage ... my rb26 is in a s15 so we used a rb25 sump ..and did a lil customising to the sump...first i had 4.5l of 20-50 oil in it and when the boost hit over 16psi the oil pressure would drop to around 35psi when it climb rpm fast ...i added 1.5l for a total of 6l and now when i boost it drops off from 82 to 70psi on pulls ...so am assuming its time to get a 7L sump to help combat the problem.. but even how its set up now am still satisfied as am only revving 6k and getting 70 plus psi will over the 10psi per 1000rpm rule... and yes the bearings had damages to them from the break in period of just 600-800km on low to no boost .... also my tach was off so it was more like getting 3.5bars at 4200 rpm with the wider clearance and staying there... hope this info is help full to other builders so rule is...... wide clearance require bigger pump or oil pressure will be on the sad side......

yes I understand how the oil system works ..this build has zero blow by ..and as for rev ..its prob seen 5000k to redline 5x in its 400miles... when my pressure drop off its usually from a 2nd gear pull. not going tru the gears and shifting hard .. I simply accelerate from 2k and by 3k my oil is up to 60psi.by 4 stays around 65 and by 5k falls off to about 55psi and would stay there to redline if I hold it.

its a new pump.the old and the new one wouldn't have the same problems .different housing ect ..yes the pick up inspected and clean. and oil drain bk mods at only 225hp if that much would mean this motor has serious issues if its needed .

the air pick up was sealed with a sealant and gasket ,,, it is questionable as we didn't get the proper o-ring to go there... the builder had a theory that it could be sucking up air after 5k why it showed the drop in pressure.... 2 of my close tuners keep telling me the clearance are to wide and they have all worked on builds exceeding 800whp ... so am gonna just go with what they say... what i will do however, is that before i change the bearings i would take down the pick up and insert the proper seal put back in some oil and see what the pressure looks like .if it looks better i would leave the bearings as is

the block we used had its own girdle ... we tried the old one just to see if the clearance would change in our favour but it did not fit correctly.

ok .so just checked the oil pressure with another gauge and am getting around the same reading of 74-78 on cold start....... think my best bet is getting some cosworth size 0 bearings .. to reduce the excess clearance

the gauge has been in the car for a while ..prob 10 years..am going to try a different one today and see .. and when the rings broke I installed the new pump after to ensure the old one was not damaged. but the result was the same .. @kiwi i didn't see the results .but the measurements were checked with a bore gauge then checked again with the plastic gauge .. maybe the gauge could be at fault. because both engine with tight and wide clearance had the same reading with the n1

the stock restrictor was in the block thanks still

thanks for your input gareth87. but i dont believe its a spring issue simply because the spring acts likes a waste gate...for example a 10psi spring allows you to build 10psi of boost then the excess gas a dumped creating a stable boost.. the pressure relief valve does the same but stock relief is usually 100 psi... if it was a case if not allowing more than 60 psi of oil pressure to build then i wouldn't be getting 80 psi on a cold start.. am leaning towards the pump cannot deliver the required volume to build the necessary oil pressure ... but this only makes sense if the first builder lied when he said he plastic gauge the engine because the first time the engine went up it had close clearance of .0015 its basically a 400whp a tomi pump is over killed for the project...

well ..I Have to explain so I could get proper help..smh

??

ok guys. i had already made a post 'wide bearing clearance' but the guys started their own topic and bypassed my question i have some new information and would like some builders advice.... i bought a rb26 moto that came with a damage oil pump.... i changed the oil pump and installed a new n1 crank also ....i also replaced the bearing with std acl ones .the builder said he checked the clearance and they were on target around .0015 ..on start up of that moto we got a average of 82 psi ....we dynoed the moto and at 300rwhp the rings cracked ..i noted that the oil pressure was a lil low on the dyno but i cant remember the exact number when we took down the moto we saw that there were scratches on the cylinder walls and decided to use another block we had access to as we had already went ahead and bought forge std pistons..we basically switched the the block and the girdle only..we use the old oil pump ,water pump, crank ect....we measure the crank journals and it was in specs....we also noted some scores on the old bearing that suggested low oil pressure or clearance to close....the crank also had a lil score on the journals but the builder said his experience that damage was small and shouldn't be a problem we measured the clearance in the new block and it was wide with std acl bearing....0025 of the max .0034 .. we consulted with some guys who build drag racing rb26 and they said it was a lil wide for a street car but they used similar specs on there drag cars that goes 8sec in the quarter.. now when we started the new moto we got back the same 80psi oil pressure... but the problem comes when the car gets up to temp i see only 60 psi at 5k and ad we go up to 6k it backs off to 52 psi as if the pump is running out of steam... i then changed the oil pump and to a new n1 and replaced the gears with reimax gears for safety ..on start up the psi is the same and i still have the same low psi behaviour at high rpm. i used 20-50 oil in both builds also..royal purple i also changed the little o-ring by the oil filter on the block to ensure that pressure was not dropping off their ..i also looked at the pick up and it was clear ..but i also noted that the builder used silicone instead of the o-ring between the block and the pick up with a gasket my question is why am i getting these strange oil pressure behaviour between builds with the .0015 clearance and .0025?? .am aware the wider clearance suffer from lil less oil pressure , also is the n1 pump capable of delivering enough oil with the wide clearance ,,,?? i know that i should be getting 100 psi at start up with the n1... what else on the engine could be responsible for leaking or lowering the psi .? could the oring by the pick up cause this much difference? am really out of answers and ideas ...please help....

sorry to say you guys are drifting from the topic about my psi issue

yes we plastic gauge all...am really not comfortable with the pressure now as it drop dangerously low when the oil heats up...now am getting a max of 4 bar after 5k and it slowly drops to 3.5 bar after that... so its park up time i dont wana try to mask the problem with a big pump which may end up failing also .... am looking for some bearing to drop the clearance from .0025 to .0015 ...am from the caribbean and am getting a hard time finding a company who makes them, i checked for cosworth size 0 bearings but its been 3 weeks and no reply from them.... any help at all locating some bearings like those will be much appreciated

I don't believe its pressure relief issuse. that's there to stop the oil pump from passing a set psi which in a n1 about 105 psi...if the valve was the limiting of 70psi I wouldn't be getting 80psi on cold start..

yes I have on reimax gears..but am concerned about the oil pressure level... would a oil cooler help maintain that oil pressure. I noticed when driving tonight that when the car heated up my oil pressure went down more...and is 70psi sufficient?

so even with the reimax gears its still prone to break?

Hey ...am desperate for some professional advice on my rb26.. we assembled my moto with main and rod bearing at .0025 - 0028 ... we used standard bearing size and measured it properly. I know its wide but it still within in factory specs of max 0.0034.. I have a n1 pump with reimax gears fitted .on start up am getting 78psi ...when the moto is warm am getting 30psi at idle... at around 5k reving am getting between 68psi ans 72 psi and the pressure will stay there.. The service manual says at 6000rpm u should have on average 66psi. so while am within factory specs am a honda driver and am accustomed seeing 90psi and rev to 9500... Am using 20-50 none synthetic oil ..still in break in period.... I have tried to locate bearings to bring the clearances to at least 0.002 but am having a hard time.. I know its not all about psi ... am not looking to race the moto just get it up to 400hp .. would the moto be ok with 70psi ??..not looking to rev pass stock limiter either.. Am trying hard to aviod a expensive jun or tomi pump... would a lil thicker oil help?

Hey ...am desperate for some professional advice on my rb26.. we assembled my moto with main and rod bearing at .0025 - 0028 ... we used standard bearing size and measured it properly. I know its wide but it still within in factory specs of max 0.0034.. I have a n1 pump with remix gears fitted .on start up am getting 78psi ...when the moto is warm am getting 30psi at idle... at around 5k reving am getting between 68psi ans 72 psi and the pressure will stay there.. The service manual says at 6000rpm u should have on average 66psi. so while am within factory specs am a honda driver and am accustomed seeing 90psi and rev to 9500... Am using 20-50 none synthetic oil ..still in break in period.... I have tried to locate bearings to bring the clearances to at least 0.002 but am having a hard time.. I know its not all about psi ...but am not looking to race the moto just get it up to 400hp .. would the moto be ok with 70psi ..not looking to rev pass stock limiter either.. Am trying hard to aviod a expensive jun or tomi pump... would a lil thicker oil help?