Any Nissan Silvia Turbo owners amongst us?

I agree, CA18DET betterererrer

May I suggest you check out www.zxoc.co.uk - a site for 80's Nissans, Bluebird, Silvia etc. A good proportion of our cars have the CA18ET (mine included) so we tend to be pretty knowledgeable on them 135bhp as standard and I think 200bhp is a realistic target on stock internals.

Single cam engines in my experience seem more reliable and less prone to valves burning out, oil usage, compression problems etc,. I have no idea why this should be. On paper the twin cam version of it (CA18DET) is a stronger unit

I've got a super nice low miles engine and box here by the way if you get stuck finding one near you.

They have a normal block, not aware of head gasket being a particular problem on them, if it is it is probably an age issue as the gasket if original will be 25 years old! Personally i would keep the power level fairly standard, then they stay reliable. They are a nicely balanced unit as standard and like you say, the small turbo gives it nice low down power.

Maybe just a little tweak then! The car weighs less than a ton.... so won't take excessive boost to bring you nearer to your god in a 40 year old car. I read on one forum that the head gasket problem was only a problem without an intercooler. I have a 'supercooler' here I built for my old LPG fitted 827 Vitesse but it got nicked before I had a chance to fit it cos I was trying to find a temp gauge that would go down to -50C. I have digital ones here in the lab' but they look lab' not auto. Will probably have to use one in the end or at least temporarily but need to keep my eye on the coolant temperature returning to the vapouriser or it could freeze up.

Anyway... as you probably know LPG boils at -44C so the cooling device should cool the air going in to the engine well below that of a standard air to air intercooler so I'm hoping will give much bang for my buck as well as not stressing the head by keeping it cool. Is going to be interesting to see.

From what I've seen the engine does have a big loom with it.... I was expecting something a lot simpler but I managed to get a diagram and looking at it it should be fairly simple if you take all the gizmology out of it and just use the ignition set up. Obviously.... if you are using petrol this isn't possible but your point regarding space is definitely relevant cos the chargecooler box takes up a fair amount of space and I want to try to keep it in line so it doesn't interfere with the induction flow.

I'd like to take it up to 200bhp.... even Norm would be ok with me calling it a 'pony' car if it had that kind of power As I said earlier the only weak link is the rear axle so it might just be a case of easing it up gradually..... but I'm not the kind of driver that shows off at every possible opportunity but would be nice to have it there if you need it for the odd hothatch kid that p*sses you off.

Decided to stay with the 8 valver cos it does appear to make it a lot simpler for a few reasons and the electronics is one of 'em. So.... if the wiring is simpler there's less to go wrong.... another plus for the 1.8 over the 2 litre.

Yep... I'm gonna give LPG only a go. Main reasons being I had the dual fuel option on the Vitesse and because of the octane difference... LPG/High Petrol/Low it's hard to set the engine up ideally for both. It just ends up being one big compromise. Also the rapiers petrol tank is in the rear of the boot so I can remove it and get a torpedo tank in there quite easily and it also has a spare wheel carrier under the boot so by taking that out I can put a torroidal underneath. With 2 tanks..... a couple of solenoid valves and a T pieced filler I've always got a reserve. I've already got all the LPG kit except the Blos but is only a £100 for that. The turbo engine will provide the higher compression the LPG needs to burn efficiently and I can throw all that detonation stuff... knock sensors etc in the scrap skip cos I won't be needing it. Don't forget that LPG has more energy than petrol.... about 3MJ/litre..... but it needs higher compression to release it. I've also got the supercooler I built for the Vitesse but never fitted it which will cool the air charge considerably using the -44C coolant from the vapouriser which is really gonna be interesting to test.

The idea is to make an ecocustom you need to see my 'Arrocuda' thread on the Readers Rides board to get the whole picture.

Plan in the longer term is to build a CA18et engine with standard pistons in order to increase the CR to nearer the optimum ratio. As far as I'm aware.... but feel free to correct me if I'm wrong cos that's really what this thread is all about, the ignition is autonomous from the all the other input sensor circuits with the exception of the knock sensor. When the ECU receives a signal from the knock sensor it retards the ignition but under normal circumstances.... ie no detonation occurring...... there is no signal therefore no retardation of the ignition. LPG is a high octane fuel so detonation cannot occur so why do you want to keep the knock sensor? If the knock sensor sends a continuous signal to the ecu and the signal is interrupted and the ecu responds by retarding the ignition then I'll leave the knock sensor on but the engine won't knock so it doesn't really matter.

I like the simplicity of this set up as there is no need for any other sensor information so again is less to go wrong. No fuel pump required but there is no feedback loop to the ecu telling it to shut the engine down cos there isn't any fuel. So does it matter? I guess if any of the devices such as injectors need to be there to keep the ecu happy you could always put dummy loads on instead which is basically how a multipoint LPG system works but at least I don't have Lambda to worry about.

These are the things I was hoping someone could confirm to me as the information I'm giving you here has come to me from threads I've read on various Nissan forums. I know the CA20DET is far more sophisticated than the CA18ET and is why as I said earlier I don't really want to go there. Fitting the standard turbo engine will give me the chance to sort all the mechanicals and sort out any bugs..... rebuilding a complete engine is for the future.