Jump to content
SAU Community

Recommended Posts

Had a quick search but couldnt find anything, having an odd problem with the car (R32 GTR).

Just had some Tomei Poncams installed and when the car hits 0.75 bar boost it sounds like its misfiring (its not misfire though) and the turbos (hks gt2530's) start to surge (e.g going "woosh woosh woosh woosh woosh woosh").

Anyone know what could possibly cause this problem? The car drives fine around off boost, but as soon as it hits 0.75 bar it runs into the above problem. The car ran 1.5 bar no problems before the cams were installed.

From what I was told the in cam is +4 and ex cam is -2, all the shims were also replaced and valve springs.

If anyone has any ideas what could be causing it, would be appreciated.

:mad:

Link to comment
https://www.sau.com.au/forums/topic/54801-rb26-boost-problem/
Share on other sites

mine does it as well although my cams are set on "0" on my degree wheels, which means very little other than a starting point for which to gauge changes by. I stop it by simply changing down a gear and moving out of the surge line.

Have you have it dynoed since the cam change? my torque starts to drop off after 4800rpm since I've installed the cams so I guess I will need to retard them to move the torque curve to the right a bit to get back the top end rush. I change gear now at 5000rpm cause the torque drops off so much after that.

Mike

mine does it as well although my cams are set on "0" on my degree wheels, which means very little other than a starting point for which to gauge changes by.  I stop it by simply changing down a gear and moving out of the surge line.

Have you have it dynoed since the cam change? my torque starts to drop off after 4800rpm since I've installed the cams so I guess I will need to retard them to move the torque curve to the right a bit to get back the top end rush.  I change gear now at 5000rpm cause the torque drops off so much after that.

Mike

Havnt had it on a dyno but done extensive road tuning with it. Whats wierd is once the car warms up (oil temp over 70 and water temp at 80 - 85) it does it a few times, and then it clears up and doesnt happen again until you cold start the car and wait for it to warm up where it does it a few times again, and then clears up and doesnt happen. Very wierd problem.

And the cams are far from dialled in from factory, all in all after this experiance, ive come to the conclusion the camshafts are -far- from a "bolt in" item...

try setting it back to "0" / "0"to start with then retard the inlet ( this will move the torque upwards in the mid to top range) and adv the exhuast ( this will widen the lobe centres given a broader torque delivery0 THATS THE THEORY ANYWAYS :D

I'm off to the dyno tomorrow for some extensive testing on my own GTR so I'll let you know my results if you like.

Mike

  • 2 weeks later...

Nik

Can't be the cams that have made the difference, as my car is doing it as well! and it has not had any changes since the dyno day. 1st time I experienced it was using OCTANE booster - it foulded the iridums, which i replaced with coppers. This solved it for a few hundred km's, but it has since returned.

I have read other posts that point to the coilpacks.... I'll be checking these and changing my fuel filter.

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

    • Pre-empting heat management  1. The Kraken manifold will be ceramic coated 2. Just purchased some peel and stick heat shielding stuff from car builders, I'll cover some of the firewall behind the dump and a little on the cam cover, this will be done prior to installation as I have ample room to get where I need to now before that realestate has more bits in the way, I'm also planning to modify the OEM heat shield to go back on, but that won't happen until after installation so I know where to hack it up, I'll also cover it with some some peel and stick to neaten it up after the hacking 3. As the dump is stainless with a flex joint coating isn't really a option, and wrapping isn't recommended for a stainless dump, so once it is installed I'll grab some shielding from car builders to cover the dump, as it has some stand off, it "shouldn't" cause any issues and it "should" just keep the radiant heat away from " melty engine bay stuff" Not for heat management, but I've grabbed some more black crinkle coat to paint all the shiny intake pipes, I'll pick the pipe work up prior to installation and use the paint booth and big oven at work to cure them, I'll then wrap them with some bubble wrap so they stay nice during installation
    • We're back on, gang - Our yearly pilgrimage south to our favourite cafe for an awesome brekkie! Yes, that's right... we're heading down to Austi Beach Cafe for a breakfast run through the Royal National Park! Before you drool over your phones/keyboards, here are the details: Date: Sunday 23rd February Meet Location: Loftus Oval Carpark, Royal National Park, Sutherland Meet Time: Meet at 7:00am for a 7:30am departure Destination: Austi Beach Cafe, 104 Lawrence Hargrave Drive, Austinmer Map: http://tinyurl.com/saunsw-austicruise  RSVP: If you are planning to sit and have breakfast with us, please let us know, either by posting in the event, or by messaging us direct so we can confirm numbers with the venue. Itinerary: We will meet at Loftus Oval Carpark which has plenty of room and is low car friendly. This is a quick turn into the Royal National Park and some nice roads and scenery. After Stanwell Tops we will turn off and head onto the awesome Sea Cliff Bridge. Following this it is a short trip to Austi Beach Cafe. There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a Motorsport Australia permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU:NSW and thus, treat others accordingly. • Any misbehaviour will not be tolerated and you will be asked to leave. Thanks guys and hope to see you there!
    • YO- have been searching and searching for an a31 chassis plug pinout, or someone who knows which wire is for tach.  ceffy was flooded past dash during a hurricane.  having an electrical gremlin appear. tach is wonky reading consistent with a short, and on occasion the right side of my speedo lighting will flicker just for a second then go back to normal.  if no pinout available does anyone know if the tach harness opens or branches anywhere behind the dash? im suspecting a possible root behind the radio as there are more shorts in that area on the accessory loop.
    • Means something is not set up right, tune/calibration related.  
    • Finally replaced the previous temporary mesh indicator surrounds (temporary was the last 10+ years 😂) with a 3D printed GTR style version for the front indicators. I think it looks a lot nicer than the old setup and at least the indicators now point in the correct direction rather than angled off. Needed a little bit of tweaking to deal with the intercooler piping but got there in the end. Old and new photos below. 
×
×
  • Create New...