SnekDoc

Had it compression tested again, readings were C1: 100, C2: 95, C3: 105, C4:110, C5: 100, C6: 110. Better than last time time and at least fairly even but still lower than originally. Air appears to be leaking into crankcase so consensus is going to need a rebuild. Time for a whole new rabbit hole and a lot more money. Now need to find out how far I want to go upgrading things if I'm having it rebuilt. My goal was to eventually make it a track-ready 2.8 but wasn't planning on doing it this soon. I know you guys aren't big on HKS parts, but since I'm not doing the work myself what do you think price-wise about going with a complete engine like the HKS step 2 or the Tomei one vs having a shop rebuild my engine with all the equivalent done?

I'm in the U.S. I have another tuner I can go to that's a bit farther away that I know is good, the main reason I went to the one I did is they are much closer, I had heard good things about them wrt RBs, and the tuner that is farther away wanted to do additional things to the car that I didn't want to do / pay for at the time. My main concern right now is getting the compression back, and if that is something the shop caused that I should try to get them to cover or if I should cut my losses and go to the other tuner.

They won't give me the password for the tune. I'm going to pickup a kit and do a leak down test to try to figure out what is leaking, but any other way to figure out if it's something the shop did to cause this or if it just happened?

I'll have to get a leakdown test kit and learn how to use it, I'm still pretty new to all this. Looks like the tune is password protected so I'll try to get the password when they reopen in a couple days and send it over, I appreciate the help. I knew I was going to get shit for that here

Is it true that if I put a little oil in the cylinders, compression test it again, and if results are the same then it is likely head gasket or valves?

Haven't tested with a multimeter yet but stock gauge shows around 14V. After a couple drives it doesn't seem to have any more power. As far as compression goes, I didn't put the car on the dyno before the turbo swap but it feels like it has less power than before and I was on stock turbos before, so it would make sense that compression is lower since the boost is higher now. Is there anything simpler / cheaper I should have checked before going the route of a rebuild? Maybe the head gasket or valves?

Had a turbo swap done from twins to single with some other parts replace (below). Before I brought it to the shop to start the work, I had to compression tested and results were C1-115, C2-118, C3-119, C4-121, C5-119, C6-119. Half way through the work we found a problem and had to get more parts so the car sat for about 8-9 months without starting it. When they finally had everything sorted and put it on the dyno, it was only making around ~260hp at 15psi with an HKS GT3-4r. They compression tested it after and results were C1-70, C2-90, C3-100, C4-100, C5-100, C6-100. They think that the reason it isn't making power is because of the low compression, and they think the low compression could be due to it sitting for months or the engine just waring down. They think there's a chance that compression could come back after driving it for a couple weeks, if not they are suggesting a rebuild. Any suggestion on what could have caused compression to drop so much suddenly? Anything in particular to check? Could it actually be from the car sitting for 8-9 months? Mods done: HKS GT3-4r HKS Manifold HKS Downpipe HKS Fuel Rail HKS Fuel Pump HKS Coil packs HKS BOV ID 1050x injectors Tomei Fuel Pressure Regulator Greddy Boost Controller Platinum Pro ECU

I was having a new fuel pump put in my r32 GTR and the shop says they found rust in the tank and it will likely need to be replaced. I know the fuel tank in the r32 GTR is plastic, but is there metal baffling or something else irreplaceable inside that could be rusting that would cause me to need a new fuel tank?

That’s interesting because the T51r and T04Z have much different rear housings. I ended up going with a GTIII-4r, the new version of the T04Z. Should be up and running next week so I’ll see how it turns out.

Okay I’m going to go this route and wait to do the crankcase ventilation proper. Really appreciate the help everyone!

Okay after doing some more reading, I think this will be my plan. Assuming compression and leakdown test come back fine I will leave the stock oil pump for now, don’t pull the engine, and shoot for about 330kw for now. I’ll stay away from the circuit and keep it under 7500rpm. In about 6 months or so, pull the engine and make it track-ready: HKS or nitto oil pump Sump baffles Valve cover baffles Restrictor in oil feed to head Crankcase ventilation 2.8 stroker Oil cooler Potentially extended sump Does this sound okay or is this a bad idea to wait and do the oil mods later? Maybe I will also do crankcase ventilation now since it sounds like it can be done easily by venting via the dipstick tube to oil/air separator?

Would I be able to hold off on oil system upgrades for a while if I defer going to the track? Does more boost in itself require more oil flow and higher pressure, or is it the extended high RPMs of track use? I feel like if I’m going to have to have the engine apart and crank removed to do the oil system upgrades, I might as well save up and do pistons/rods or maybe even a stroker kit.

Thanks for this info. I’m still very new to all this. I’m going to keep reading the oil control thread, but based on the first 10 pages it sounds like to solve the oil problem the engine will have to be pulled, the head lifted, and the the sump removed anyway. It sounds like people are saying to add a crank collar, upgrade oil pump, fit a restrictor in the supply line to the head, add another external return to the sump, and install baffle in the sump. It’s still not clear how necessary this for a mostly street car that will see track days occasionally since this seems to be more of a problem of extended high rpm use. @joshuaho96I have not read about issues with the crankcase ventilation so maybe that is later in the thread. While I have already learned much more from this thread, I have lost confidence in my build 🙃

Yeah that’s what I thought based on what I’ve been reading but I wanted to double check, there’s only 2 shops around me that specialize in RBs, and there other one is overly aggressive and won’t do the setup I want. So assuming the compression and leakdown test come back fine, it’s only oil and fueling I have to worry about? I’ve read a bit about the oil problems in RBs but I’m not sure how far I would have to take it for this setup. Upgrading the oil pump is probably a given but should I also be installing a restrictor on the head and upgrading baffle in the oil pan? Or anything else?

Tac says 75,000kms but unverified. As far as I know, the motor is from 1990 when the car was made but I don’t know if it is the original motor.

I am planning on going single turbo on my r32 GTR. My goal is about 500whp for now. Without knowing the condition of my motor, my local shop wants to do the following: Inspect block and crank Replace bearings Oil pump upgrade N1 water pump Metal head gasket Cams And I think they wanted to do ARP head studs but I can’t remember for sure. My question is, is all this necessary / worth it for this power level and not knowing the condition of my motor? Besides injectors, fuel pump, coil packs, boost controller, and ECU, is there anything else I should be doing?

That is my instinct but I wasn’t sure. To me it seems similar to how how RBs with twins and an equal length front pipe have a distinct sound at a high RPMs, so I thought it might be related to length of separate exhaust channels before they merge.

Nothing I said has been contradicted. I said “I don’t think muffler or catback have anything to do with the sound I’m after”. I posted 2 videos with different exhausts with different materials and while overall sounding different, the part of the sound I’m after is present in both.

I agree I don’t really expect to but it’s worth a shot. It’s hard to describe what I’m looking for. To give a better example, here’s the same car with 2 different catbacks made from 2 different materials. They sound very different but both still have the part of the sound I’m looking for.

It means quality in the sense of tone quality (a sin wave would be perfect tone quality with no distortion or other frequencies in the tone). I think a better word for it would be texture or color of the sound. I agree that mufflers and catbacks make a big difference in the sound, but based on the different setups I’ve heard I don’t think the catback portion of the exhaust is responsible for the aspect of the sound I am after.

I don’t think muffler or catback have anything to do with the sound I’m after. Yes they make a difference in the final sound, but what specifically I am after (as shown in the videos I posted) is a fundamental change in the timbre of the sound. In my experience catback does not change the timbre much, or at least not in the way that I’m looking for.

Yeah I agree, I’m not looking to buy the same turbos I’m looking to achieve a similar sound with a modern more efficient turbo. I think the reason most of the videos I’ve seen with these turbos have the similar sound is because these turbos are often sold in kits including a manifold and downpipe. Based on what I have seen so far in other people’s setups, it seems like parts of the exhaust with multiple pipes, the manifold (and downpipe if using twins), have much more of an effect on the timbre of the sound than single pipes like a test pipe and catback do. Any insight into what to look for in a manifold to get this sound? Is it just equal length tubular manifold or is there more to it? I’m assuming twin scroll would also affect it.

Exhaust

Yeah I’m definitely not a fan of the screamer pipe sound. I’d like to have performance and sound

This is a noob question, but I am looking to get rid of the stock twins on my bnr32 and go single turbo. The car is mostly a street car and sound is important for me since it's a big part of the driving experience. I've watched a lot of videos of different setups, I've noticed not all single turbo setups have the exhaust sound I'm looking for and I really love the sound RB26s with T78 or T04z turbos, but I don't need that much power and I want something more modern and efficient. I'm looking to make between 500-600whp. Can I get the same exhaust sound from cars with those turbos with something for modern like a GTX or G series turbo? Does the actual turbo influence the exhaust sound much or is it mostly the manifold design? Does twin scroll influence the exhaust sound a lot? Any help would be appreciated. Vids of the sound I'm looking for: