zboi

320 to the wheels is really not that much. I had 400 for a while, then 600, now back to 300, all this with no form of structural bracing. Did I ever launch on slicks on a prepped surface, no, but surprisingly I never had any issues putting the power down. If I were to pick I'd say around 500whp is the most I'd ever want to be. For 425whp, just get an LS3 and call it done.

To wrap this all up, it made 308hp 358lb/ft at 4510RPM 17PSI. Power was climbing the whole time, but it ran out of injector at 4500RPM so I limited all runs to this. More power than expected. Plenty of power for the street, but to be safe I will step up to bigger injectors.

Everything is verified and accurate and I'm running slighty rich actually. I'm just putting this info out there to help others. So many people scratching their heads replacing head gaskets all the time, this is why. Meanwhile my engine is running 14PSI with stock head gasket, no deck work, no head studs, everything stock with no issues.

So I had moved and left my car behind, but now that I'm back I did some more testing. I was unsure how accurate the knock sensors were as I was seing knock retard even when the motor was not in boost. Turns out they are 100% accurate. I put in some 104 octane and gave the car a spin. 99% of knock retard was gone. It is now quite obvious why people blow these motors so easily. I was getting knock retard throughout the 7psi (absolute PSI so 7 away from being "in boost") band from around the 3.6K+ RPM when using just 93 octane. I was getting up to 13 degrees timing pulled at higher boost. With the high octane it was only pulling timing at 14PSI boost, with a resulting spark advance of 20degrees. It will spin tires in 1-4th gear easily.

Buy it and let us know. I wouldn't worry about changing the bottom end. Stock stuff is big and heavy, should be strong enough if tuned correct, just don't rev it too high. You will want to run e30+ fuel

You don't need to change anything internally. Typically you would add some top ring gap on a turbo motor, but these motors already have plenty. My build is probably the cheapest high tech option possible, and I am very happy with the turbo's response and power. Back in the day it would be simply swapping some junkyard turbo model parts, but these days they are rare and not worth it. There are many ways to go about it, main factor is budget.

To add bushings to the front mount (they did add that) To properly bush the diff mount (not done) To change the brace so it fits in a 240z without smashing the spare tire(not done) Then a number of things about suspension optimisation such as what was posted in this thread.

I got mega burned by Apex on the rear track attack. Was one of the first buyers of it and back then it didn't even have enough parts to even bolt it to the car. The design of the rear kit is just for looks. Much feedback was given to them in how to improve it, but it was widely ignored. Shame because the cradle design is a good base to start off of.

I was doing some thinking and think that I have discovered an excellent trick to get some higher compression and better piston rod characteristics from a stock dish piston setup. I don't have the parts in my hands to take exact measurements, but it seems like you can take an L28 with dish pistons, swap in 240z rods (2.65mm longer) and then remove about 2.15mm from the dish piston tops. This should get them to be basically a flat top, with depending on head gasket and block deck height, a nice tight clearance. You get the performance benefits of better rod ratio, smaller trapped area between top ring and piston top, and higher compression for minimal costs. Anybody do something like this before?

I saw them selling for $6200 in Europe. They are CNC heads already so I wouldn't expect a whole lot more cost for the DOHC variant. Derek what you've done is cool and all, but my gripe is that you stopped making the head a long time ago. Why not share the files with someone like Edelbrock so they can make a head for the masses. We're at the point where L series are becoming scarce and manufacturers don't even have incentive to make parts for them anymore.

Don't worry PAMS is already testing a real DOHC head on cars and you will actually be able to buy it. I expect prices to be better and unlike this head it will install without a headache and an engineering team.

These are not just bare heads, but unmachined heads. And it's just one not a pair. Yes inflation has been ticking up substantially, but not long ago you could get a pair of assembled ls3 heads for $800. Derek came in here to try and stroke himself for a ten year celebration, but let's all be real this cylinder head was made for himself. Dude wants to keep it for himself too.

Don't fool yourself man, nobody has this head, it's just a talking point.

You ever think about liscensing or giving the design out to a real head manufacturer? Its been so many years thay we have gotten to the point that L series engines are disappearing and becoming less and less popular, and you have only sold 22. You haven't actually done anything tangible for the community. Now if a real company made some heads like this for about the $1000 they should cost, then the world would change.

Ooof 40 and 80 are really bad. Bad results wet would point to broken/pinched ring, but if your really lucky a sooted up ring. I used something called b12 chemtool in my cylinders when I got the motor. It had been sitting outside at the previous owner's place and got some water in the intake. To my surprise it cleaned up perfectly and had 135-140 compression on all cylinders. Valve sticking would be very obvious to spot with the valve cover off, you would see a valve noticeably lower than the rest, unlikely to be the issue though.