Nismo34GTT

Guess it's just trial and error for me then. Really thought there would be some people here who have some knowledge on this kind of tuning. When the car came in, the knock at idle was steady around 0-2. When I was drag racing it, I saw the numbers hit up to 60, even up to 65 a couple of times. That's with the tune it came with. With the exhaust advanced, the crank is showing 30 degrees as the timing (but the power FC is now showing 21/22), which matches the math above. We are 8 degrees advanced, so the real timing is 8 degrees retarded from the mark on the crank pulley... Question answered. With the timing at 22, knock at idle is 0-2 and bounces sometimes up to 20/25, then back to 0-2. When I'm going WOT she hasn't gone above 25 on the knock. The last run was 18-20. She's boosting hella fast and breaking the tires on shift through 3rd. The Apexi turbo on this beast causes her to spool about 500rpm faster than a normal turbo of the same size, and now she's spooling even earlier thanks to the advancement of the exhaust cam, plus the knock has gone down. She's a mean one.

The cam gears have 48 teeth. The crank rotates twice for each cam rotation. 360 degrees divided by 48 teeth = 7.5 degrees. Now you halve that because the cam turns at 1/2 the speed of the crank, which gives you 3.75 degrees. I don't think I'm being brave at all, but rather setting the motor for optimal performance in drifting. Advancing the timing should create faster spool, use less fuel, and give more power in the lower and mid range bands. As per TDC, there is no need to re-mark it. TDC is still TDC regardless, as this is based on the crank position and the crank pulley has not changed it's position on the crank. It can't change position because of the key-notch. What I am trying to figure out is the base timing. The cam being advanced 4 degrees changes the position of the CAS. The CAS position is what adjusts the timing in regards to what the flashing light shows on the crank pulley. Because the CAM is advanced 4 degrees, this means the crank should be about 8 degrees retarded before the CAS is in the "stock" position for 15 degrees BTDC. So does this mean that base timing is now set to 23 degrees BTDC or 7 degrees? If I go to 15 degrees with the exhaust cam advanced, we aren't going to actually be at 15 degrees BTDC because the exhaust cam is not in the stock position.

The car is running at it's best with the exhaust cam advanced 4 degrees. It ran really well at 8 degrees advanced and another configuration with the exhaust advanced 4 and intake retarded 4. At stock timing it runs good, but sounds more like a NA motor where it's "lobing", and that's not preferential for induction engines from the reading I've done. So at the end of the day after testing 6 different CAM configurations, we set the exhaust to 4 degrees advanced and the intake to stock position. We chose this configuration because it had the lowest knock readings on the power FC (2-4). Now the Question is... HOW do I set base timing in this configuration? And is it better to use the wire on the ignition module for coil pack one, or to loop around the 3 wires of coil pack one with the timing light? I seem to get a better signal from the ignition module, but most posts I've read say to use the coilpack. They also say to disconnect the TPS, which seems to make very little difference on my end.

I retarded the exhaust cam by 1 tooth (about 4 degrees according to other forum postings), and now the FC is showing 28 degrees while the gun is showing 15 degrees on the crank pulley... Now we are off by 13 instead of 8 like before, which leads me to believe the exhaust cam was advanced 8 degrees before I pulled it apart the first time... Going to advance it next and re-test.

I recently purchased a R32 drift car from Japan that is pretty well built. It has a RB25DET block with a RB20DET head, which I've never seen before, but the car pulls like a mother at the track. I decided to go ahead and do all the routine maintenance on the engine recently, including changing the timing belt. I was trying to get ready for a drift event today, and in my haste I made a careless mistake. I did not set the engine to TDC before removing the timing belt, and thus I didn't see if the timing was actually set to factory or not by whoever built/tuned this motor. I put the timing back to stock and installed the belt. This is how I've always done cars - put them to their factory settings. When I start the car now, it runs hella rough. I have a Power FC on it and the knock was in the 40s to 60s upon start up. After some tweaking I got the knock down to 0-5, but it still runs like crap. I disconnected the TPS and connected my timing light to coil #1. I set the timing on the crank pulley to 15 degrees; however the power FC shows 22-23 degrees. When I adjust the power FC to a -7 or -8 on the timing, it shows 15 degrees on the power FC; however the engine no longer shows 15 degrees on the crank pulley. I'm fairly new to performance engines. This engine was running amazingly well before I took it apart, and now I can't get the timing set for the life of me. Based on what I've observed, I'm guessing the previous mechanic had set the exhaust cam 2 teeth off (8 degrees) from the stock timing mark. This is the only thing that makes sense to me as to why the Power FC and Crank Pulley timing marks don't match, as my thinking is that the Power FC was tuned with the exhaust cam 8 degrees off. I've read where people do 4 to 8 degrees on the exhaust cam to get more mid-range power and quicker boost from the turbo; and since this was a drift car that would make sense to me. Because I'm new I thought it would be best to ask the community about this issue before I reset the timing. Thanks in advance for your help!

Today I hooked up a 5psi source to the wastegate, and it moves just fine. No idea why it was overboosting. We checked the fuel pressure and it's a bit higher than it should be, which I've read happens sometimes when you go with a higher lph pump due to the extra fuel being returned to the tank, causing a bit of a pressure buildup. We took some coilpacks off another RB25DET, swapped them on, and sure enough that was it. Set the timing and now she runs perfectly! Thanks for the help

I didn't remove it, but took a pair of pliers and was able to move the rod back and forth without any issues. I'll try a compressor today as well.

Thanks for the feedback. I'll try swapping out the coilpacks tomorrow and see if that fixes it.

I just got a R33 and have been working on it just over a month now with a friend. Since received the car has had boost issues whenever it's under throttle. Sometimes the boost gauge doesn't go past 5-7psi with the car sputtering like crazy under acceleration. Other times the boost gauge shoots way past 10psi almost instantaneously. First we checked the compression to find 170-180psi across all 6 cylinders (most were 180). We then removed the plugs, cleaned them, gapped them (0.035-0.040) and re-installed. No difference. We heard an air leak from the intake side when we first got it, so we took off the manifold and replaced all gaskets and hoses. The air leak was gone but the problem persisted. We took out the factory fuel pump and filter, put in a new filter and a 340lph fuel pump. Problem persists. We tried two aftermarket manual boost controllers. We used every vacuum diagram on the web for a R33 boost solenoid (sadly there are literally guides stating that every way to run the hoses is correct). We removed the heat shield to the turbo and could move the wastegate manually, so chances are it isn't stuck. Problem persisted. We then ran a hose directly from the charge pipe (coming off the intercooler to the intake pipe), directly to the wastegate (bypassed the solenoid) which should give us 5-7psi. The problem persists. When you're driving anywhere below 3psi the car runs like normal. It has a factory ECU with zero codes. Stock turbo, stock intercooler, stock piping. The only aftermarket mods are HKS plugs, Apexi Filter, and downpipe/exhaust. Neither of us has any idea why this car continues overboosting causing a horrible sputter. We appreciate any help this community can offer.