Jump to content
SAU Community

Recommended Posts

Hi Bass I had the same problem with your turbo just like Grepin one of the first guys here to run this turbo. You can increase the pre load on the actuator rod but at the end of the day I always had the same problem - boost dropped to 16 psi at about 5000rpm. I adjusted that actuator to the point just before you couldn't control boost.

You can get a 19 psi actuator from gcg the hks ones are 1 bar standard. I was thinking about doing it but lost interest in the end. We tested the one on your car with the air compressor and it opens at one bar like it should. Grepin ended up buying a .86 exhaust housing but it made no difference mind you grepin was making over 312 rwkw. I had 260. Interestingly we ran the same 1/4 times. What sort of boost control do you have? The PFC one won't help as it doesn't bleed off air it's just a electric valve that opens and closes very quickly. I believe the eboost ones are the go but pretty pricey.

Nice power figure hope you're enjoying it.

  • Replies 129
  • Created
  • Last Reply

Top Posters In This Topic

fwiw i have the hks actuator that come with the turbo and it holds to within 1 psi @ up to 21psi

and i have ony ever seen a 40 knock once (limiter in 3rd)

fwiw i have the hks actuator that come with the turbo and it holds to within 1 psi @ up to 21psi

and i have ony ever seen a 40 knock once (limiter in 3rd)

Are you just running the hks actuator and no boost controller? If you're running a boost controller what type are you running?

blitz DSBC spec s :)

If it bleeds air off from the wastegate line then it's probably a better controller than the pfc ones. That might be all bass needs I'm not sure what boost controller he's running.

bass's car was making boost on the hot side and not on the cold tho.... i'm guessing there was a boost leak and that it was sealed up when the piping was replaced te last time

I thought I mention it. The other thing that with boost drop could be the compressor is out of puff assume the turbine housing is big enough. Which is probably why you don't really see boost dropping issues when running big turbochargers.

I've noticed that on few SR20s who's running ATR28G3 and G4 turbos that developed a issue which the stock rubber intake pipe gets sucked shut over certain boost range. So boost rise to 18psi and drops back to around 15psi. this issue gets solved once a metal intake is fitted.

For most people who's experiencing "boost dropping" issues on RB25s are mostly with smaller turbochargers running on 60mm and 71mm comp wheels. which really do make me think back to the above situation which the compressor is not be able to supply enough air to actually support above 20psi to a 6cyc engine at high RPMs.

I think this matter would be in the turbo design, The compressor of the turbo needs to be large enough to flow the right amount of air to support its application with the right turbine to dispatch compressor flow. This really leads me to think some of the early HKS turbos are not made as a very balanced setup or is not engineered to produce high boost efficiency on the RB25det.

in theory that is possible, but the issue at hand was not a boost drop, but boost dissapearing between the hot and cold sides of the intake piping.

therefore it could have only been a leak, as the compressed air HAS to go somewhare, it cant just vanish.

also incorrect sompressor sizing cant be the case, as the turbo in question has been tested time and time and time again on RB25's with near identical results across the boad...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Did this end up working? Did you take some pictures?
    • And finally, the front lower mount. It was doubly weird. Firstly, the lower mount is held in with a bracket that has 3 bolts (it also acts as the steering lock stop), and then a nut on the shock lower mount itself. So, remove the 3x 14mm head bolts , then the 17mm nut that holds the shock in. From there, you can't actually remove the shock from the lower mount bolt (took me a while to work that out....) Sadly I don't have a pic of the other side, but the swaybar mounts to the same bolt that holds the shock in. You need to push that swaybar mount/bolt back so the shock can be pulled out past the lower control arm.  In this pic you can see the bolt partly pushed back, but it had to go further than that to release the shock. Once the shock is out, putting the new one in is "reverse of disassembly". Put the top of the shock through at least one hole and put a nut on loosely to hold it in place. Put the lower end in place and push the swaybar mount / shock bolt back in place, then loosely attach the other 2 top nuts. Bolt the bracket back in place with the 14mm head bolts and finally put the nut onto the lower bolt. Done....you have new suspension on your v37!
    • And now to the front.  No pics of the 3 nuts holding the front struts on, they are easy to spot. Undo 2 and leave the closest one on loosely. Underneath we have to deal with the wiring again, but this time its worse because the plug is behind the guard liner. You'll have to decide how much of the guard liner to remove, I undid the lower liner's top, inside and lower clips, but didn't pull it full off the guard. Same issue undoing the plug as at the rear, you need to firmly push the release clip from below while equally firmly gripping the plug body and pulling it out of  the socket. I used my fancy electrical disconnect pliers to get in there There is also one clip for the wiring, unlike at the rear I could not get behind it so just had to lever it up and out.....not in great condition to re-use in future.
    • Onto the rear lower shock mount. It's worth starting with a decent degrease to remove 10+ years of road grime, and perhaps also spray a penetrating oil on the shock lower nut. Don't forget to include the shock wiring and plug in the clean.... Deal with the wiring first; you need to release 2 clips where the wiring goes into the bracket (use long nose pliers behind the bracket to compress the clip so you can reuse it), and the rubber mount slides out, then release the plug.  I found it very hard to unplug, from underneath you can compress the tab with a screwdriver or similar, and gently but firmly pull the plug out of the socket (regular pliers may help but don't put too much pressure on the plastic. The lower mount is straightforward, 17mm nut and you can pull the shock out. As I wasn't putting a standard shock back in, I gave the car side wiring socket a generous gob of dialectric grease to keep crap out in the future. Putting the new shock in is straightforward, feed it into at least 1 of the bolt holes at the top and reach around to put a nut on it to hold it up. Then put on the other 2 top nuts loosely and put the shock onto the lower mounting bolt (you may need to lift the hub a little if the new shock is shorter). Tighten the lower nut and 3 upper nuts and you are done. In my case the BC Racing shocks came assembled for the fronts, but the rears needed to re-use the factory strut tops. For that you need spring compressors to take the pressure off the top nut (they are compressed enough when the spring can move between the top and bottom spring seats. Then a 17mm ring spanner to undo the nut while using an 8mm open spanner to stop the shaft turning (or, if you are really lucky you might get it off with a rattle gun).
    • You will now be able to lift the parcel shelf trim enough to get to the shock cover bolts; if you need to full remove the parcel shelf trim for some reason you also remove the escutcheons around the rear seat release and you will have to unplug the high stop light wiring from the boot. Next up is removal of the bracket; 6 nuts and a bolt Good news, you've finally got to the strut top! Remove the dust cover and the 3 shock mount nuts (perhaps leave 1 on lightly for now....) Same on the other side, but easier now you've done it all before
×
×
  • Create New...