CowsWithGuns

Saga complete, coming back with a summary before bed Installed the smallest kelford cams, replaced the turbo, added an NZ wiring trigger kit for good measure. No more problems, only good times. Interesting bonus feedback from the tuner is the knock threshold has improved, and there is room for more power with more boost, but he advises against it due to the stock rods + reused bolts in my motor. Back to back boost curves show no change, implying that the turbo failure had no relation to the root issue. They had no trigger issues in the first place so no reason to suspect the NZ wiring kit to be the solution. Hence, we conclude my stock cams were faulty somehow as indicated by measurements of duration (exhaust side), and the symptoms presented. Cam centrelines at 125 and 114 per kelford's recommendations, no changes made on the dyno. Car is fun as all hell, I'm traction limited in 1st and 2nd which is where most of my fun time is anyway. Major gains from 2000 rpm onwards, subjectively no change at 1500, significantly slower sub 1500. Probably due to the cams (?), but the improvement is violent at exactly 1500 so I think that's the currect VCT-on threshold and could be lowered. Regardless - car drive, car good, car fun Time to take a break and enjoy, then get some ABS and aircon back in the beast! Many thanks to everyone who shared their advice and moral support during the trouble period

Could ya'll comment on this borescope image of cyl 1? Some of the others have shiny spots or larger brown areas, or shine 'cleaned' edges, but this one has these small marks on both edges where the valves are, that may or may not be small dents (hard to tell on my resolution). What causes this, is this likely to be shrapnel?

@Kinkstaah speaking off the ill fated 7064, feast your eyes on this. What happened? Who knows. No sign of shrapnel in the manifold or the cat. Going to borescope the motor but I expect to see no damage. Perhaps the heinous noise I heard was the bearings flogged out due to getting sent to full boost on that unbalanced turbine dozens of times - if I want to engage my cynical side, this was already the condition of my 'never used' second hand turbo This is my lazy boost explanation, heck maybe the exhaust gases were going into all sorts of chaos and losing me power too (but idk). I've finished my sulk period and got my monthly pay, action time! Ordering Kelford 244As and shims, adjustable gears, replacement supercore, upgrade my triggering with something cheap and sensible. Get tuned under orders: 'give me the beans, boss' and whatever I get will be the finished build for this RB25 (except for maybe flex fuel so I can utilise the turbo fully).

Did you change the E-Throttle table? Yes, no more hole. Is the wastegate setup with correct preload? Ensure its sealing Generous preload applied, 14 psi spring, added closed loop for full duty cycle on spool up (subjective modest improvement in spool). It's those new fancy twin port IWG actuators. The top port (pushing gate open) seals per air compressor test. Bottom port does not seal, air leaks out past the piston at a decent rate. My understanding is this is by design for safety - but since you mention it - I didn't confirm that it should behave that way. Is the boost solenoid plumbed correctly? Tuner plumbed it to his preferred way after I agreed to the recommendation to ditch my 4 port. It is done like so, except the tee is using the top port of the wastegate actuator (it has the option of two fittings on top of the membrane). Is the turbo a 7064 .92 rear? I have bought something and didn't check and was wrong housing but that early dyno chart shows is what I would think is lazy for this size turbo. Yes, placard on it states so Can you do some logging in 4th gear under load and also a trigger scope? Unfortunately car is kaput until my turbo is repaired/replaced. Turboman called me today and said, 'you should come and have a look at this' with no further info so I expect to see a pile of shapnel for bearings on my lunch break tomorrow. I don't know what a trigger scope is, but I'll find out and do so once I'm back on the road. Here is some low speed 4th gear WOT spool data from what I have saved - this is at 0% duty as WG DC doesn't start until 2500 on this tune. Do you know anyone you can borrow an aftermarket CAS like a NZefi or similar? No, but I'm happy to buy one as it seems like an essential reliability upgrade anyway. I'm thinking of doing that and perhaps adding a cheap crank trigger while I'm at it soon. Since my turbo did fail within a week and I have confirmed oil supply, did pre-oil with a syringe til it dripped out, it's plausible it was f**ked from the beginning and that may explain the lazy spool.

Forgive me Father for I have sinned by proliferating misinformation online. From the r34 service manual translated to English: My cam nose heights are roughly in spec, and it appears the stock DET NEO lift would be at most 7.63mm (assuming a 32.00 round, I measured slightly above that). There is the open question why Tomei says the factory lift is 8.7mm. Begging someone who has some old DET Neo cams rotting in storage to whip out the ol' calipers or micrometer and present their factory high lift big boys Despite my turbo failure, my blade speeds were +/- 5% of what is expected from matchbot so during its one week lifespan I can only assume it was fine. And I made identical peak power on a much bigger turbo. My mate helped me do some more detailed data analysis and nothing seems out of place on the tune and sensor side. Any ideas guys? I'm back to square one. I NEED A HERO!

Occurred in 2021. f**kers raised the price substantially over the quote on the phone, and tried to force in extra work I explicitly didn't want. YMMV. But theres a reference for ya. Didn't get it balanced and didn't need line boring. Should have got it balanced (get it balanced).

Sounds like you have engine issues. Compression and/or leakdown test would be my first call (either gain peace of mind or rip the bandaid off) followed by fuel pressure check, vacuum leak check to get your basics covered. IDK where you're at with tools but I've had great luck with ebay fuel and comp testers, and my ebay leakdown went straight to the bin. Assuming your starting issues are related to the power issue, I wouldn't expect the exhaust to be a (major) concern as if it was really blocked you'd be flatlining power early and it would be fairly obvious. Nothings impossible though!

This is becoming something of a dark comedy. I will be spending some additional time in this relentless purgatory of R34 ownership. Two days ago I noticed a pretty loud tinking noise from my engine bay at idle. After reassembling the car after my camshaft investigation, I went to track it down. Tinking coming from the turbo... it's f**king siezed when you spin by hand (but spins perfect (visually) when engine is on). Inbound removal and offloading to a turbo shop with clear instructions: fix. Cherry on top, I started the car for just a second to confirm oil supply and discovered what turbo oil supply is like. Generous, in abundance, and over all surfaces great and small in the engine bay. @Kinkstaah few more moments like this and I'll be on my way to saying damn it all to hell, lets put an LS in it.

I was seriously considering this and it would be a wonderful explanation/conclusion, however my camshaft is marked with U6. Photos online of a DET neo exhaust cam have U6, whereas DE Neo has U7, so I don't think this is the case. I went ahead and measured a few extra lobes and they are all 6.9 - 7.3 (variance primairly due to measuring error with adjacent parts screwing my caliper alignment). They really don't look that worn, so I'm disturbed. Intake cam measures up perfectly normal, is cast with 'U8' (but it could also be U6, the marking is rough as guts), and the lobes are taller than on the exhaust (by about 1-2mm) just by looking at it. Height 39.5 Round diameter: 32.4; net lift = 7.1 Casting U6

~0.3mm on intake and ~0.5mm on exhaust. These are the measurements I took via feeler gauges prior to reshimming:

Made a degree wheel and took some measurements. I could not find details on stock camshaft duration and position at 1mm, so I am using the smallest tomei 'drop in' camshaft as a sensible reference for duration. My dial gauge was really really touchy and would move around 0.2mm give or take, due to the scuffed clearance to the lifter (sometimes rubbing on the camshaft)to take to access the valve, so give a generous tolerance to my measurements. I don't understand camshafts enough to have confident conclusions, but my observations and thoughts are: Intake cam seem dead on perfect, HOWEVER, my lift measured is 8.5mm (caliper), ~8.6mm (dial gauge) and the factory spec is 8.4 according to Tomei. Strange but does not worry me too much. Exhaust cam seems totally rooted! Cam lift spec is 8.7mm and I measure 7.2mm with calipers and 7.0 with dial gauge. Accordingly, my duration is 20 degrees lesser than my intake cam! The lobe centre is also advanced by 5 degrees (+/- say... 3 degrees), but the significance of that is lost on me pending further study. Edit: measured two other random lobes, both ~7.0 to 7.2 on calipers. The nicest, shiniest unworn looking lobe was 7.0 ?? Is it reasonable or at all normal for a camshaft wear out that much? The engine ran on very loose clearances (up to 23 thou) on the exhaust side for some time, I reshimmed in Oct down to 18/19 thou and the valve train noise settled a lot. Would this wear be a symptom of those loose clearances or the cause - or is it both in a vicious cycle? In case the clearances tell a story, here's my notes from Oct: Here's two pictures of lobe 1. To me it looks fine? My amateur eye is looking at lobe 3 and thinking that looks crap, but I would have not thought much beyond that (until now). So I assume the path forward is to get a spare factory exhaust cam or a pair of mild kelfords, and then adjustable cam gears on both sides and reshim them tight. Zip it up, back to the tuners, and miraculously find another 60+ horsepower and achieve The Goal. But what could have caused this problem to begin with?

The tuner on whether I am knock limited and the possibility of more timing advance: "Regarding the ignition tables, the values we have in there are on par with the other 25neos we have tuned and are confident in where they are set. I’m not sure what values you’re comparing as the table axis was originally set to MAP but have now been changed to display that axis as MGP. That can make it a bit confusing to compare to different tunes if they have their tables set up differently. But as far as the it being knock limited, yes that is the case in the low end/mid range as it comes onto boost but that is typical on this sort of setup and yours didnt seem any worse than usual. " I don't know what to make of all this. Ye wise SAU veterans say the advance is less than normal - my tuner says it's normal. I went on a hunt to find tuned, well performing neo files online to see for myself but only found one (admittedly with ~2 deg more advance on the top end) but that's a sample size of 1 lol. No doubt they are out there so I just need to search harder. Does anyone have a comparable R34 tune file that performs mint for me to look at? I also received this as my final result.

Here is a WOT run in 2nd gear after I fixed the throttle target table. Unfortunately I don't have anywhere nearby where I can full send in 3rd or 4th. What indicates this to you? I haven't done it yet but can do - just curious what gives that away to you? I also turned on closed loop just for stage 1 clamp. I feel like my spool improved a decent bit afterwards, but that could just be placebo. Interesting you say this. I noticed on my previous build (stock throttle) that in first gear the car definitely felt more powerful at something like 80-90% throttle rather than all the way, but only some of the time. I thought I was going crazy. PC Datalog - 2024-02-8 2;32;37 pm.llgx

Hahahahah, well spotted gang. Here's the story there: I put in e-throttle and tuned it to driveable state so I could drive to the tuners. That's my work there (noob me didn't fill right but interpolated vertically, and didn't realise theres more to the table). Tuner never noticed it, never ran into issues. On the drive home I experienced what felt like a boost cut protection at 6000 rpm and found that after slewthing the next day. I decided not to bring it up here as on the dyno TPS was still 99% so it wouldn't be relevant - and I didn't want to highlight my ineptitude on the laptop I ended up emailing the tuner just to verify there wasn't some strategy there but realised that this was definitely my work lmao.

Yeah, I've been hung up on that. Ok, latest and greatest action plan is 1. Verify my cam timing, attend to it as required. If I need to take timing belt off for any reason, adjustable gears (and the boost doc VCT adjustment thingo) are going on - only wish I knew their value in the past. And yes, stock cams. I forsee nothing to gain by upgrading to some mild kelfords or poncams, but happy to be told otherwise. 2. Get it on a dyno again with explicit request to optimise ignition advance (not that this is something that should need to be said but anyway...). Things are looking a little grim for the recent tune, but honestly just the constant comms and the tuner chatting to me for a full hour after I arrived really did put them in my good books so I'll *probably* take it back - and he had a folder full of powerful R34 dyno logs I glanced at so I'm erring on 'theres a reason for this' rather than incompetence or otherwise. Regardless, I will contact and ask - and the answer will guide my decision on return, or f**k it and gamble with tuner #4. I'm time and money poor but thankfully only acutely. I did just spend 3 fulltime weeks and like 10 grand on this build over xmas + tune/diag fees. Will probably not have more to share until I do the above... and I could do with a rest - this whole procedure has taken a toll. Huge thanks to everyone for your support! Maybe there will come a time I will be the one with a happy car and a brain full of experience to share here