SimonR32

as i said before this is not only a problem with IHI (Apexi) turbos but i have seen it happen with HKS 2530 and HKS 2535 as well as Garrett 3071's i will test to see what happens when i dissconnect the actuator arm tommorrow... if it is to do with the actuator not opening enough would the solution be as simple as just adjusting the arm to be longer? it is not a problem with the dump, as the car had a standard dump on when it came over from japan and when i put on the china dump it actually made it a little better

if the internal gate is too small it will not allow enough air to flow through creating a larger pressure in the manifold and the only way this air can flow is through the turbine blades... which cause them to spin faster and therefore increase boost pressure hense why engines making more horsepower need bigger external wastegates

there is no cat 3 inch front pipe and 4 inch cat back the dump pipe is a hks copy china split dump, it has been ported to improve flow as some of the welds are a bit dodgy standard... i talked to a very reputable performance workshop mechanic today and he said that they have to port the internal wastegates on all rb25 highflowed turbos otherwise they have the same problem... he also said that a bit of porting to direct the flow to the wastegate helps as otherwise the exhaust gases will just flow past cause of their high speed. so it looks like its die grinder time. ill have to take the turbo off and find out how much i can increase the diameter of the wastegate without changing the flap, hopefully should be about 3mm or so. may as well also give the dump pipe a little more of a port and match as well to help improve flow even more

good idea... i shall have a try on the weekend by the way my actuator arm is adjustable, i have not touched it since it came over from japan any more other suggestions/solutions?

I have a Apexi AX53B70 internally gated (aftermarket actuator) 380hp turbo on my RB20DET, but I have heard people with similar problems with HKS and Garrett internally gated turbos as well. I am having problems with the boost creeping as the engine rises through the revs and it can not be controlled to hold less than 20psi approaching redline. This is NOT a boost controller problem as it is unable to hold boost to less than this with the actuator line connected straight to the turbo outlet. Is there any way to fix this as sometimes i would rather use low boost to conserve my engine (eg: drift and track days) The car used to only creep up slowly towards 1 bar when it arrived from japan, but now i have increased the intake and exhaust flow (by changing the dump pipe, larger FMIC and air filter) it will not be controlled to anything under 1.4bar. I am assuming that this has to do with internal gates lack of abilty to flow enough air to lower the boost pressure. Therefore I have been approached with 2 options that may work... 1. Buying a aftermarket manifold to suit a external gate application, weld the internal gate shut and use a external gate to control boost. 2. Improve the flow of the internal gate by using a larger actuator flap and grinding out a larger hole to improve flow Neither of these options appeal to me as they would involve modifying my expensive turbo. Also the first option which i know has been known to work on other cars is a fairly expensive process when you have to buy a external gate, manifold and new exhaust to suit the high mount. Does have any bright ideas or solutions to the problem, i know it is not only me struggling with this so any advice for a cheap solution would be much appriciated Thanks in Advance Simon

not a great difference... hks is rated as 340hp and garrett at 350hp

trust turbos are oil cooled/plain bearing and based on mitsubishi items... hks turbos are water&oil cooled/ball bearing and based on garret items... it would have to be said that hks turbos are much better

painiting a cooler black technically makes the cooler more efficient

still waiting for delivery has been 4 working days now... getting a bit worried

yes

run run run dont go near prestige motorsport if u can possibly help it

also u can map the knock over the different load poitns with the computer software which is a great help for a more accurate tune

rb20det ap engineering uses rb25 datalogit software... it will take a LOT less time to tune with the software simply because it is easier to change multiple load points at the same time

2535 will get 1 bar of boost @ around 3700ish on a rb20det, depending on the tune of course looking at making 300rwhp @ around 18-20psi depending on mods my mate has one on his 20 and goes very well, should run a easy 12

3rd or 4th gear 4th would be better but watch out for the police

paid on friday and i dont have mine yet hope its coming soon, do you have to sign for the package?

Another 60+hp from 5psi more boost, power fc tune, new cooler etc etc. My car now with the pfc makes 1 bar of boost at 3500 instead of 4700+ than when i ran my 12.8 with the remap. Also hopefully a slightly faster 60" time Its my aim... I'm not saying I'm going to be able to do it, I'll be happy with very low 12's for the moment

tomei pistons aftermarket rb26 rods aftermarket full counterbalence rb26 crank you should be able to make very decent hp with a rb20 with that much spent... there is at least one rb20 over in japan with a T51R strapped on the side

settings air flow meter scroll to 80mm vg30 press previous that should select it

235rwkw @ 20psi that is the most i have seen from the turbo and kind of setup u have

japanese retunes are almost always really rich and lots of timing... your best bet it too get a new chip, if the old one isnt siliconed onto the board or go for another computer like a ap engineering power fc

mine aim is 11 on stock box and rb20 dont think ill be too far off next time i get down there... getting off the line may be the biggest problem

f**king idiot

I just swaped my GTR cooler for a 100mm hybrid design copy with aluminium piping the cooling capacity is better and the turbo is actually now more responsive (300rpm). somehow the GTR cooler was causing a restriction, i dont know how or why but it was...

GTR Intercooler in very good condition (Silver) $300 http://antilag.com/forums/attachment.php?attachmentid=1332 http://antilag.com/forums/attachment.php?attachmentid=1333 PHONE OR SMS ON 0422426866 needs to go asap