skylinecouple

When I put my Poncams in I also replaced the springs with the recommended Tomei springs. I can't say what performance difference they made as the cams would account for the extra power but the car revs clean to reline. really, if you think about it, most standard springs have been working pretty hard for quite a few years. If the head is off why not replace the springs for a few hundred dollars and know you have done things right. My power is up and torque is coming in much lower so definitely add the cams. Springs are insurance to maximize cams.

1224kgs. Fantastic. An RB25 would have been better for cruising. Still, amazing none the less.

As Bob said. Research. I cannot tell you how many times I had so called experts tune or set-up my car and fail miserably.

I had the same problem. It does affect the idle and definitely affects low rev cruise quality and mostly acceleration. By acceleration I mean backing off or cruise then move the accelerator and there is a flat spot or hesitation. Accel-enrichment does not help. Disconnected the O2 and drives just like a factory car. I have since changed all cells at light load and cruise to 14:1 AFR and run without a O2 sensor. It is better on fuel consumption at 420-430k to a tank and drives beautifully.

Hurry up, I'm old. Want to see this finished before I die.

I've made comments before about fake factory coils. Factory boxes, factory coils, part numbers stamped on boxes. I bought a set and sure enough, fake. Use Nengen or RHJ or Jessie Streeter. Good chance they will be genuine.

GCG Hiflows are just that, Hiflowed. If the previous owner asked them for it that's what he got. It will flow a little more than stock but that's it. I would expect 230kws at best. However, if the compressor has been changed to a more efficient wheel then more air flow will certainly cause the issues described. There is some porting of the wastegate that needs to be done as GCG usually keep the standard wastegate flap and port size. I had one years ago and this was the case. Get a porting tool and grind out the wastegate a couple of millimetres. Leave 2mm for the flap to seal against. Try this with new plugs, air filter etc. Get that boost controller working ! Why is it just reading boost ? Is there a problem ? Electronic boost controller is a must have item. Also, the fact it revs clean in 1st & 2nd makes me think of exhaust blockage. Why did you clean out the cat ? was it blocked ? you can't clean them out. If you could see daylight through it then it was fine. Cleaning it in petrol is probably not the way to do it. Is the exhaust 3" all the way through ? The cat isn't a compliance cat is it ? They are usually less than 3". So many things to look at because we don't know the car. Anyway, do the simplest things first and work from there. Oh, and you wouldn't be the 1st person to believe you had a hi-flow and it was just a standard rebuild. Get the number off your turbo and ring GCG and ask what they did to it.

Most times misfires are directly related to coils. Not that this case will be the same but yes, coils usually the case. Don't do temporary fixes on them as it very rarely fixes the issue. A new set is required. Don't fall for the new factory coils in factory packaging but ridiculously cheap. They are not real. Just get Splitfires like 11,000,000 others have done. Know what it feels like to rev to redline without a hicup.

Well said. The fact is, if you want it done right do it yourself. There might even be a couple of guys on here that might want to help. Of course time is our enemy. Not all of us have it. The good builders charge high prices but there is still no guarantee they won't make a mistake. Having one shop build it, install it and tune it is the only way I'd pay a work shop. Get all your parts off E-Bay 1st and save a fortune. Don't expect too many people to name names as we don't want o cause legal issues. However, you may receive a few PM's.

Sorry about triple post. From my end it wasn't going through. I have to think about what would it be like to have an engine like that in a 1400kg street skyline. Keep it quiet, no big cams or anything to give the game away. Even keep the auto box as less weight of the Skyline could make it last a bit longer. Not sure about the size of it fitting in the manual Skyline tunnel though.

Yes but the whole tough black wheel thing has been done to death. It really has that try hard look to it. People in the car scene are swinging more towards BBS & similar. Besides, those black wheels look soooooo heavy. One thing we noticed was the side mirrors are just too big. Perhaps something from a different model. I have to wonder what would happen if, god forbid, you were to take the car to an airport runway and try a top speed run.

Yes but the whole tough black wheel thing has been done to death. It really has that try hard look to it. People in the car scene are swinging more towards BBS & similar. Besides, those black wheels look soooooo heavy. One thing we noticed was the side mirrors are just too big. Perhaps something from a different model. I have to wonder what would happen if, god forbid, you were to take the car to an airport runway and try a top speed run.

Yes but the whole tough black wheel thing has been done to death. It really has that try hard look to it. People in the car scene are swinging more towards BBS & similar. Besides, those black wheels look soooooo heavy. One thing we noticed was the side mirrors are just too big. Perhaps something from a different model. I have to wonder what would happen if, god forbid, you were to take the car to an airport runway and try a top speed run.

Nice. Tastefully done. Not sure about the bonnet scoop. Possibly a fraction low, would not want to hit a dip in the road around a fast curve with all that weight. And why wouldn't anybody appreciate any car when it is nicely done ? Your Commondore is fine by me. Impressive power. Any thoughts of running it at the drags ?

Have you installed a Z32 AFM ? If so, some people earth it to the chassis near the AFM. Try connecting the two centre wires of the Z32 AFM together then connect that to the white/blue wire of your wiring harness. Obviously it is connected and running now but apparently with one of the AFM wires connected to the body it can cause bad running. See tutorial.

Bought new original coils several years ago. Factory boxes with all the right printing. Very professional. Lasted 3 months before severe breakdown. Bought Splitfires and been good for a year or so. Revs clean every time. There are fakes but the price will tell you that. Buy from Nissan and get raped on price. So that leaves Splitfires.

I really hope you continue as you are going. This looks good. Please don't change the body in any way. Just keep it clean and sleeper style. Good work so far. Any ideas what that Holset will make ? Do yourself a favour and change the subframe bushes as soon as you can as the lock rings aren't as good as solid subframe bushes or if you are going to use it for regular road driving then urethane bushes will be a better bet.

Me to please. Have developed a flat spot up to 2300rpm. Nowhere else. It isn't in the tune or accel enrichment either. Sorry to jump in here but good electricians are hard to find. Don't they go off when you refuse to pay cause they haven't fixed anything. I sat across the road while my car was in the work shop. He looked at it for 15mins. When he told me he had spent quite a bit of time on it I told him where I'd been for the last 2hrs. The look on his face was worth the wait. Anyway, still have the flat spot. Not coils as it revs clean to rev limiter.

"just depending where it is driven." Now therein lies the question. Track car but registered on the street would be more of 8.7:1 or just leave it standard compression. Street car would be standard comp or 9.2/9.5:1. I really like the idea of street/track car at 8.7:1/ 8.9:1 or around that. So much better at ignition control or knock control would be the better term. Bit daggy off boost but on track with the wick turned up it could be a good thing with 21lbs of boost dialled in. Back in the early 80's I had a turboed beach buggy built for a local doctor by a guy who builds lawn mowers, it's a long story but I remember the distributor had to be severely modified to get enough timing into it due to the low compression. But the moral to the story is, never blew anything up even with our caveman knowledge of turbos. Damn I miss that car.

By the way Disco, 256deg cams make virtually no difference to idle quality. It really doesn't sound cammed at all. I guess if we are only mixing parts then it really comes down to fuel used and how much lag you're willing to put up with. For the home engine builder you could clean up the head and maybe 1mm oversized valves for minimal cost. With a big enough turbo and slightly bigger cams and springs I suppose the hydraulic head could handle 8,000rpm for short periods of time but yes the Neo head is probably the best option. Neo head, bump compression to 9.5 and above mods with water injection but only if a non-leaking fool-proof system and I think you'd be on a winner. GTX3076 and who knows ? As an every day driver it would be smooth and fuel efficient with awesome response.

True, the external waste-gate is always a better option. There are of course other things to think about. If the car makes the numbers and still looks stock, well, that for me is a very important consideration when somebody opens your bonnet. Besides, if you add a waste-gate and piping you may as well get a GTR and have no room to work. It all comes down to that perfect choice of parts for minimal cost, fuel economy, standard looks, maximum strength. Though I do like the RB25/30 I decided in the end that with good tuning and the right turbo a 25 is more than enough for a street car. You know, I haven't seen anybody do a RB25 with 26 crank and rods. You could pick up a set cheap or at least the crank and get forged pistons. Anybody done this before I start mine ?

If least spent and best results are what really matters here then I am happy with my little 3071R .82 IW. 550cc Nizmo injectors, 3.5" dump, Tomei 256deg cams. This is a really great street car with a lot of work on tuning to get smooth responsive power. Fuel economy should also be a player in this thread as there is already a thread on results but not driving experience or fuel economy. This car is, and always was what I believe Nissan should have done. Economy at 480-500k for a trip and 400-430k's for town. Love it. Having said that there is a second engine in the build. Have sold the 25/30 and going to rebuild the original engine. Rb26 crank, rods, cams & GTX.

Looks good. I've seen so many videos of Russian driving, so I wonder how long it will last before it is kaputski. Just kidding Ivan. Show us more.

If it were me I'd replace the exhaust as it is obviously bothering you. Don't you just hate it when you truly believe something isn't right and 6mths later you wish you had changed it ? Seems stupid to get a tune then end up changing the exhaust anyway. Do it once, do it right. I have just changed my dump pipe from 3" to 3.5" using the cat as a step down. The difference is chalk and cheese. Whoever said a bigger exhaust slows down the flow has rocks in their head. Revs faster harder, more power everywhere from idle to full boost. Strangely, it is quieter. Now I want to go full 3.5" all the way to see what my little 3071r is capable of.

What about ripping your carpet and seats out and physically checking for cracked welds in the floor or chassis. Then get under the car with your local welder and seam weld the whole chassis. No roll cage just solid welds. Very effective. You'll need to do it anyway if the spot welds are coming apart, and it sounds like they are.