Jump to content
SAU Community

Recommended Posts

Hey fellas, I've got an issue with a hks 2535 which i have just installed on my R32 gtst...everything seems to be in order with no leaks in lines or piping but there seems to be an issue with the boost...it is EXTREMELY laggy and only starts to create positive boost above 3500rpm...which is late even for a rb20...then theres the main problem...after about 5500rpm or so...the boost just skyrockets uncontrollably and doesn't stop rising...i've accidentally hit 1.2 bar on it...the turbo has an adjustable wastegate actuator by the way...can someone shed some light on this please?

Link to comment
https://www.sau.com.au/forums/topic/159128-hks-2535-and-skyrocketing-boost/
Share on other sites

check that the actuator is opening all the way... if it is then make sure the wastegate hole on the back of the turbo is big enough to let the gasses escape... the problem here is that your exh gasses arn't escaping in effect creating more boost.. theres a few threads that people have put up with the same problem just have a look around..

also check that your cat isn't blocked

hope this helps :laugh:

Haven't left any of your original vacuum tubes unblocked?

I'd check your tubing setup too to be sure.

I installed my turbo (2535) yesterday with the most basic setup..... just the one tube going from the pressure source (nipple off the intake piping) straight to the actuator.

No boost controller at all yet but will soon.

Where are you dude?

If not too far away we can compare setups.

Working in North Sydney today

3.5 sounds about right to me my 2530 wasnt coming on much earlier than that

and wind the Actuator out to lower the boost alittle anything under .85 though and you'll get worse boost response

as hks actuators are meant to run on .85 bar

why are you worried about hitting 1.2bar, thats where my 25/30 sits at on RB25.

As for skyrocketing pretty normal buddy thats where your car is making peak torque and power, as for coming on a bit late well rb20 with that size HKS unit mmmmm. Get it Dynoed.

nah i think thats about right.. my 2535 on my rb25 starts at about 3000 and realy starts moving by like 35-3700rpm

if you disconnect the wastegate and give her a test real carefuly i think that will show you the fastest it'll boost up so u can compare.. careful thogh cause it'll run at unlimited boost

3500 seems alittle late to me for it to make positive boost but i'll have a look at the rest of the engine again...please keep the suggestions coming fellas...cheers...
why are you worried about hitting 1.2bar, thats where my 25/30 sits at on RB25.

As for skyrocketing pretty normal buddy thats where your car is making peak torque and power, as for coming on a bit late well rb20 with that size HKS unit mmmmm. Get it Dynoed.

I'm definitely not worried about running 1.2-1.3 bar on that turbo as i plan to do that in the future...i'm worried about it now though because my injectors and afm will be maxed out way before that...i have a remap and the car is tuned to only 165rwkw at the moment...with air fuel mixtures spot on...so if the 2535 is running 1.2 bar...i will defninitely be running lean...and thats even before ignition timing is addressed...so thats why...there no point in dynoing it now as i have yet to get the injectors and z32 on yet...and by skyrocketing i mean it doesn't go to 1.2 and sit there...it keeps going and thats why i got worried...

If it keeps going up and up its becasue the exh gasses are not escaping quick enough... start to point the finger at the wastegate, boost controller, turbo and cat.. think about everything that your car needs to let the exhaust gasses escape... if it don't let them escape it wont hold boost.. it'll just keep rising..

i had the same problem and mine turned out to be the wastegate hole on the exh housing of the turbo that needed to be ported out... the hks actuator should only be a 1 bar actuator or less so something is wrong... even try just connecting the vac line from the inlet manifold straight to the wastegate and see how much boost you make.. or the other alternative is to go on the dyno... save you alot of headaches and if it gets dangerously lean they stop the run.. on the road its hard to tell

If it keeps going up and up its becasue the exh gasses are not escaping quick enough... start to point the finger at the wastegate, boost controller, turbo and cat.. think about everything that your car needs to let the exhaust gasses escape... if it don't let them escape it wont hold boost.. it'll just keep rising..

i had the same problem and mine turned out to be the wastegate hole on the exh housing of the turbo that needed to be ported out... the hks actuator should only be a 1 bar actuator or less so something is wrong... even try just connecting the vac line from the inlet manifold straight to the wastegate and see how much boost you make.. or the other alternative is to go on the dyno... save you alot of headaches and if it gets dangerously lean they stop the run.. on the road its hard to tell

Thanks mate...that kinda suspected that might be the reason...i'll have to pull it off and have a look...cheers...

dont worry man im in the same situation too, it just keeps on spiking, im thinkn just gettin a stock actuator, not this adjustable crap,and just running a boost controller

let me know if u find a solution and if i got one i'll let u know, coz its annoying the hell outa me

Hey fellas, I've got an issue with a hks 2535 which i have just installed on my R32 gtst...everything seems to be in order with no leaks in lines or piping but there seems to be an issue with the boost...it is EXTREMELY laggy and only starts to create positive boost above 3500rpm...which is late even for a rb20...then theres the main problem...after about 5500rpm or so...the boost just skyrockets uncontrollably and doesn't stop rising...i've accidentally hit 1.2 bar on it...the turbo has an adjustable wastegate actuator by the way...can someone shed some light on this please?

do u have a boost controller connected up?

if so, take it off and connect the hose directly from the compressor housing to the actuator.

My HKS GT2535 does the same on the RB20det with R32 actuator. It goes 11psi roughly and then creeps to around 15psi with no boost controller.

I thought the acuator was stuffed so tried a RB25det one. 7.5 psi and then creeps up around 12 or something LOL. The turbo is coming off soon so i might grind the f**k out on the waste gate area.

You would think HKS found and rectified this problem, c**ts they are.

my personal opinion is that if you can afford a HKS 2535 and the required supporting mods, then you can also afford poncams + adjustable cam gears to make it come onto boost a lot earlier. i wouldn't be surprised if you could get it down 500-800rpm based on my own personal experiences

Thats the way they work!! You put a bigger turbo on, you get more lag, more power, more lag, nothing in the world will stop this from happening!! Cams will give you better mid range and bring boost on a little earlier but not by much.

My RB20 runs a HKS2530 and it behaves exactly how it should, boost is on by 4000rpm and rises to 18-20psi.

Goes like a dream. Maybe you were expecting something else. I have never seen a big power turbo make boost below 1000rpm, that is total crap!!!

The HKS internal wastegates are second to none. If you think you can improve on them good luck!!

You must run a boost controller on these turbos and they need to be dyno tuned. Bleed valve is only $50. Come on now and get serious, I cannot believe some of the rubbish that is posted..

Thats the way they work!! You put a bigger turbo on, you get more lag, more power, more lag, nothing in the world will stop this from happening!! Cams will give you better mid range and bring boost on a little earlier but not by much.

My RB20 runs a HKS2530 and it behaves exactly how it should, boost is on by 4000rpm and rises to 18-20psi.

Goes like a dream. Maybe you were expecting something else. I have never seen a big power turbo make boost below 1000rpm, that is total crap!!!

The HKS internal wastegates are second to none. If you think you can improve on them good luck!!

You must run a boost controller on these turbos and they need to be dyno tuned. Bleed valve is only $50. Come on now and get serious, I cannot believe some of the rubbish that is posted..

Gee...thanks for the technical lesson...i'm a certified mechanic and mechanical engineer and been involved with turbo cars for 4 years...as if i didn't know that a bigger turbo would cause more lag...when i said positive boost at 3500 (NOT 1000rpm) i meant that the boost gauge would read 0.0bar at 3500 or more...now that i know for a fact is abit late...i'm asking for opinions and suggestions here...i don't need to know that i need a boost controller and i need a dyno tune...so before you try to teach me how about you read your own crap first...i don't NEED to run a boost controller if i don't want to...if you say the hks actuators are second to none then they will hold whatever boost level they're meant to hold properly...

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

    • OK, so regardless of whether you did Step 1 - Spill Step 2 - Trans pan removal Step 3 - TCM removal we are on to the clean and refill. First, have a good look at the oil pan. While you might see dirty oil and some carbony build up (I did), what you don't want to see is any metal particles on the magnets, or sparkles in the oil (thankfully not). Give it all a good clean, particularly the magnets, and put the new gasket on if you have one (or, just cross your fingers)
    • One other thing to mention from my car before we reassemble and refill. Per that earlier diagram,   There should be 2x B length (40mm) and 6x C length (54mm). So I had incorrectly removed one extra bolt, which I assume was 40mm, but even so I have 4x B and 5x C.  Either, the factory made an assembly error (very unlikely), or someone had been in there before me. I vote for the latter because the TCM part number doesn't match my build date, I suspect the TCM was changed under warranty. This indeed led to much unbolting, rebolting, checking, measuring and swearing under the car.... In the end I left out 1x B bolt and put in a 54mm M6 bolt I already had to make sure it was all correct
    • A couple of notes about the TCM. Firstly, it is integrated into the valve body. If you need to replace the TCM for any reason you are following the procedure above The seppos say these fail all the time. I haven't seen or heard of one on here or locally, but that doesn't mean it can't happen. Finally, Ecutek are now offering tuning for the 7 speed TCM. It is basically like ECU tuning in that you have to buy a license for the computer, and then known parameters can be reset. This is all very new and at the moment they are focussing on more aggressive gear holding in sports or sports+ mode, 2 gear launches for drag racing etc. It doesn't seem to affect shift speed like you can on some transmissions. Importantly for me, by having controllable shift points you can now raise the shift point as well as the ECU rev limit, together allowing it to rev a little higher when that is useful. In manual mode, my car shifts up automatically regardless of what I do which is good (because I don't have to worry about it) but bad (because I can't choose to rev a little higher when convenient).  TCMs can only be tuned from late 2016 onwards, and mine is apparently not one of those although the car build date was August 2016 (presumably a batch of ADM cars were done together, so this will probably be the situation for most ADM cars). No idea about JDM cars, and I'm looking into importing a later model valve body I can swap in. This is the top of my TCM A couple of numbers but no part number. Amayama can't find my specific car but it does say the following for Asia-RHD (interestingly, all out of stock....): So it looks like programable TCM are probably post September 2018 for "Asia RHD". When I read my part number out from Ecutek it was 31705-75X6D which did not match Amayama for my build date (Aug-2016)
    • OK, Step 3, if you need to remove the valve body, either to replace it, the TCM, or to do a more complete drain.  First, you need to disconnect the TCM input wires, they are about half way up the transmission on the drivers side. One plug and the wires are out of the way, but there is also a spring clip that stops the socket from sliding back into the transmission. On my car the spring clip was easy to get, but the socket was really stuck in the o-ring of the transmission housing and took some.....persuasion. You can see both the plug to remove (first) and the spring clip (second) in this pic Incidentally, right next to the plug, you can see where the casting has allowance for a dispstick/filler which Nissan decided not to provide. there is a cap held on with a 6mm head bolt that you can remove to overfill it (AMS recommend a 1.5l overfill). Final step before the big mess, remove the speed sensor that is clipped to the valve body at the rear of the box.  Then removal of the Valve Body. For this the USDM Q50 workshop manual has a critical diagram: There are a billion bolts visible. Almost all of them do not need to be removed, just the 14 shown on the diagram. Even so, I both removed one extra, and didn't check which length bolt came from which location (more on that later....). Again it is worth undoing the 4 corners first, but leaving them a couple of turns in to hold the unit up....gravity is not your friend here and trans oil will be going everywhere. Once the corners are loose but still in remove all the other 10 bolts, then hold the valve body up with 1 hand while removing the final 4. Then, everything just comes free easily, or like in my case you start swearing because that plug is stuck in the casing. Done, the valve body and TCM are out
    • OK, so if you are either going for the bigger fluid change or are changing the valve body which includes the Transmission Control Module (TCM), first you should have both a new gasket 31397-1XJ0A and a torque wrench that can work down to 8Nm (very low, probably a 1/4 drive one). You can probably get by without either, but I really didn't want to pull it all apart together due to a leak. First, you now need that big oil pan. The transmission pan is 450 long x 350 wide, and it will probably leak on all sides, so get ready for a mess. There are 24x 6mm headed bolts holding the pan on. I undid the 2 rear corners, then screwed those bolts back in a couple of turns to let the pan go low at that end, then removed all the middle bolts on each side. Then, undo the front corner bolts slowly while holding the pan up, and 80% of the fluid will head out the rear. From there, remove the remaining bolts and the pan is off. You can see it is still dripping oil absolutely everywhere...it dripped all night.... I got another couple of litres when I removed the pan, and then another few when I removed the valve body - all up another 4l on top of the 3 already dropped in step 1.
×
×
  • Create New...