Jump to content
SAU Community

Recommended Posts

Nah lazy coils will cause misfires, not a straight power loss...

Plugs look fine, so long as the conductors are still in tact, and the plug isn't wet or covered in unburnt fuel.

Checked the BOVs yet? Start there.

BTW A small leak in a vac line won't flow anywhere near enough air for you to even feel a power loss.

ISMR's dyno is generally considered a low reading dyno and if you say your gtr is all standard, then a figure of 160kw atw isn't that bad.

From memory with my chats to Indy, standard gtrs will do around ~170kw atw on his dyno. What did Indy have to say about it ? Standard evos/stis only do around ~140kw atw there.

And how about reversing the mods ? Install the factory exhaust and remove the boost gauge and replace the tapped line with a new one, reset ecu and then test again.

ISMR's dyno is generally considered a low reading dyno and if you say your gtr is all standard, then a figure of 160kw atw isn't that bad.

From memory with my chats to Indy, standard gtrs will do around ~170kw atw on his dyno. What did Indy have to say about it ? Standard evos/stis only do around ~140kw atw there.

And how about reversing the mods ? Install the factory exhaust and remove the boost gauge and replace the tapped line with a new one, reset ecu and then test again.

indy said there is definately a problem, other cars of the same are making 10/20kw more

indy said there is definately a problem, other cars of the same are making 10/20kw more

Hrmm fair enough.. if it was myself, i wouldn't be worrying too much about a 10kw discrepency but if you say it feels much slower.

If it was me, i'd quickly chuck that factory exhaust on and remove the boost gauge, reset and test. Could be your ecu doing dicky things like the above mentioned. Checked intake/filter condition and cleared it out with upper engine cleaner? What's the air intake temp sensor reading when doing the dyno runs as that can affect ignition timing/power.

Edited by Touge Kyousou

My gtr with kakimoto exhaust, trust front pipes and apex pods made 160kw @9psi with the boost restrictor removed. Wouldn't boost any higher than that probably due to not having an ebc. This was at boostworx in adelaide which runs a mainline dyno I think.

well i was boosting up to 13 psi, sol it should be more than 160.. :D

Yeah should be near on 200kw at that power. Maybe try another workshop for a second opinion? As people of said it could be a number of things, take it to a tuner that specializes in GT-Rs if you haven't already.

i took it to Indy at is motoring, i have only heard good things about him, he does GTR'S all the time and he said that my power is definately down..

i will tick things off as i go

i am looking for a standard computer ATM

was it done in RWD?

have you done a compression test?

what position is the CAS at?

have you checked base ignition timing?

The Dyno was in 4wd

I have checked all those things

I guess I will take to a third mechanic and see if he can figure it out.

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

    • Apologies for the long post, but needed somewhere to lay out the entire timeline of events and actions taken:   I've got an 89 GTR with a R34 RB in it. It's been running great all year, driven probably 500KM in the last month. It's not my daily driver, just a weekend fun car.    Build info: R34 RB26 - HKS 2.7 stroker kit, HKS adjustable cam gears, HKS turbo upgrades, Trust intercooler, R34 factory DENSO 440cc injectors, JUN chipped/tuned R32 ECU. All of this work was performed in Japan back in 2019.    Thursday 10/2/25 - It's a nice day and decided I'll drive it to work, I start it up in the garage and I notice it took a few extra cranks and sounded a bit funny. I figure maybe it was just because it was a pretty chilly morning. I pull it out into the driveway to warm up a bit before leaving. As I leave the driveway, it feels very off and sounds like a misfire. I pull it back in the garage to deal with after work and take the daily to work. I was able to diagnose it as a cylinder 5 misfire with the old spark plug test (unplugging each plug until a sound change with the engine running). I take off the whole ignition system, ignitor, plugs, spark. *Important note, it is still on the R32 ignition system with the separate ignitor system. I test each system with a multi-meter and nothing presents as a smoking gun. I put it all back together and it starts up no issue. I go ahead and order the PRP R35 ignition conversion kit. It should arrive today (10/13/25)   Friday 10/3/25 - Another nice day, car starts up great and drives great all day. Very pleased that everything seems to be OK   Sunday 10/5/25 - Decided I'll take it to play some golf, load up and drive to the course about 25 minutes away. Drives wonderful the whole way there, I pull in the parking lot and the engine completely comes to a stop. I do not recall if it sputtered at all, but just remember all of the sudden the engine was off. I roll it into a parking spot, try to crank it back on and nothing.  It'll crank and crank and not even try to start. End up getting it towed back to my house and push it up into the garage.    Items I have checked: Fuel in the tank Fuel Pump relay Fuel pump fuse  Spark Plugs & gap Coil packs Ignitor    I know the cylinders are getting fuel as the plugs smell like fuel after a start attempt. I tried spraying starter fluid into the manifold and cranking and not even a sputter.    I decided to do the live CAS test (removing the the CAS, ignition on and spinning the CAS stalk to see if the injectors pulse and spark is active). All of the injectors were pulsing and I have spark at the plug. The half-moon end of the CAS did seem very loose, I'm not sure how much play is supposed to be there, but it was more than I expected. There was no in/out play of the shaft, just the tip end that is pinned on had quite a bit of play.    CAS Play video   When I put the CAS back in, I stupidly did not re-time the engine. I know I need to do that tonight, however, I do not think it will start given it seemingly was not the issue. My plan is to do the PRP R35 coil kit and retime the engine at the same time.    I plan on ordering the Haltech Nexus Plug-in ECU once they are available again, but ideally would like to get this sorted before firing the parts cannon at it and potentially adding more variables.    Anything glaring that I am missing here, I'm a bit at a loss?          
    • Get it on a dyno. Get something logging Consult. Run it up and find out what is causing it.
    • Looking for a plenum for rb25 de+t neo  Not looking to push much power maybe 300kw at the wheels, is there much difference in flow for Freddy “Greddy style” compared to original Greddy or options like Proflow or Otaku garage?    I won’t be porting the de Neo head for now as I think it’ll be fine 280-300rwkw but appreciate the help and any experiences anyone has between them and any advice. Thanks  Looking at this plenum for now below 
    • engine wise almost no mods: stock ecu Greddy front mount intercooler Greddy forward facing intake w R33 TB stock fuel system, stock injectors, rail etc. Kakimoto racing hyper 3 inch exhaust system Apexi intake filter New NGK –R BCPRES (.8 gap) plugs  
    • Nice one @Pac - looks like a fair few 1600's there! 
×
×
  • Create New...