To further what I said above their some options open to you.
Most people shy away from the idea of a Turbo / Supercharger and/or nitrous with a JSpec for a couple of reasons although the most popular is being told by other people you can't do it. This is obviously not true and maybe inspired by a little ZE jealousy and probably not a full understanding of whats involved. It does, however, mean some design considerations relating to det control and cooling but the fact is that at the end of the day similar energies are going on inside a ZE as a DE, it just means you need to run LESS boost to make the SAME power.
There is no magic in this, the higher compression ratio of the ZE means with a lower boost you have the same air in the cylinder at the end of the compression cycle e.g. for 275 bhp = 9.2 CR + 7 psi or 10.1 + 4 psi - BTW these figures are totally made up off the top of my head and are not meant to be factual just representative.
You can actually work out the difference if you can calculate the static versus combined or actual CR of the two however this wouldn't be totally correct due to difference in the inlet port design and different air resistances and more importantly cam profile differences.
This brings me nicely to a genuine down side of ZE boosting and that is the cams. They are typical high compression, high revving, high airflow cams (cams have nothing to do with CR or revs) with a much bigger overlap than the standard cams found in the DE engine. These give an improvement in normally aspirated engines by getting more oxygen into the cylinder come ignition stroke.
The way they do this is by increasing the time both intake and exhaust valves are open allowing the fresh air to 'flush' out the old burnt exhaust gas but by doing this you loose some inducted air out the exhaust before it has done anything. The idea is that you gain more by having more fresh cooler (denser) air and therefor more oxygen available for burning fuel (the key for making power) than you loose by 'giving away' air the engine has worked hard to get into it in the first place.
The problem in a turbo engine is the balance doesn't work out the same, the same process basically becomes a boost leak to the system and you loose more power than you gain (in most cases) by doing this.
The same is true when injecting nitrous oxide as it is just wasteful to piss nitrous out the exhaust before it has been worked, you might as well not have injected it and will have to inject more to compensate. The whole idea of nitrous injection is to get the most power from the least amount of nitrous (not fuel
) and this is one of the main reasons to pick one make of system over another (others being for a solenoid not to fail taking your engine with it).
What this means is the std (fuel efficient) cams are usually a better proposition for use in turbo-ed / nitrous applications.
Bottom line
I suppose if you were BUILDING an engine for turboing you would probably base it on an 03/DE and replace the pistons with forged ones of a lower CR, maybe around 8.5 and replace the con rods etal with ones that can withstand a higher compressive force under acceleration after ignition. The std ones have a tendency to bend due to their light weight design (the reason the engine can rev over 7K).
If you wanted a more lively, fun(er) car you can of course turbo with std internals being careful with the boost levels and being realistic with the power output but I wouldn't buy a ZE engine, with the extra costs associated, just to turbo. That said that doesn't mean if you have a car with the ZE in you can't turbo it, I would do the same and turbo it like the DE, I am just saying don't spend the extra money you will have to part with to get one.
If you wanted to nitrous your engine then again one with std internals will be fine (as long as the engine is 90% - same as turboing) and maybe putting lower compression pistons and stronger con rods in if you are after serious power later.
Again you can nitrous a ZE, the engine probably won't be able to take as much as a DE but the nett power output will be the same with less nitrous used. Result!
One thing to bear in mind is a low CR engine is a sluggish engine. Until your turbo creates positive pressure in your intake manifold (boost threshold) you will have a sluggish car (lower CR is less fuel efficient also).
So going too low isn't good and this leaves a problem regarding nitrous use as you are only 'on gas' for approx 0.1 to 0.01% of the time you are driving (roughly dependant on what you primarily use your car for) meaning you have a sluggish car for 99.90 or 99.99% of the time were a turbo may be 'on boost' for 20% or more of the time.
I suspect the best of both worlds for nitrous use, and therefore the most cost effective, is to go for a ZE bottom end with a 10.1:1 CR and fit 03/DE heads. This would make getting a ZE worth while as you have extra power all the time and the bonus of nitrous when you 'want' it
It would certainly be a different ZE03 Hybrid that NA users go for i.e. changing in a ZE top but I think if you are looking at nitrous this is probably the best way to go.
Humm, that's got me thinking. I think I'll build one, see how it goes and let you know.
P.S. If anyone wants any engines building to any particular specs, Hybrids and/or head work with or without nitrous etc let me know and I'll see what we can come up with.
P.P.S. Sorry for the long and maybe at times boring post
. Hope it made sense most of the time as I have a tendency to go off on tangents
