What's the static compression ratio? Are you running petrol, and if so what octane, or are you running E85 (which is doable with a carb btw. There's a couple of things that won't last forever with a stromberg or SU style carb, but there is a place in the UK still making them and parts for them (SUs at least) and they have alternate spec floats and I think they also altered the material they were making need needles from, to better handle long term e85.

It'd probably also be a big factor to show us pics/diagrams of the exhaust and intake manifolds you are using. You can gain or lose a fair bit with respect to that. Even the 'worst' manifolds out there, it wouldn't be unrealistic to get around 200bhp with an a15 and enough water or methanol (or possibly a mixture of both) to avoid detonation altogether.

No matter whether it was efi or drawthrough carbed (well within reason - assuming teh intake manifold is designed well enough for good mixture distribution) basically if you get the right amount of fuel in there and avoid detonation it will 'work' well. But take it slowly. Run low boost and see where the mixtures are, and alter the needle profile to suit. And then go up 1-2 psi at a time, and watch the a/f ratio like the engine's life depends on it (it pretty much does). That _will_ mean you'll need an EGO sensor and display/logger to properly track it (unless it is all done on a dyno). They aren't dirt cheap, but you only have to buy it once, and it's way cheaper than a brand new engine!

There's little (if any) risk in running quite lean for part throttle cruising. Since the comp ratio should be lower than a typical non turbo car, and the fact at part throttle you only ingest a much lower amount of air/fuel, then it won't be nearly as highly compressed at TDC compared to full throttle (and night and day different compared to full throttle and full boost pressure). So in those conditions you can run very lean. In fact you can essentially run it as lean as it will go without causing a misfiring (which with good ignition systems is somewhere leaner than 17-17.5:1. You'll find part throttle economy will improve as you lean it out all the way to that region, but around that region, going much leaner, even if it avoids the misfire, it will only show a much lesser improvement to fuel economy. Even if you don't care about economy, the leaner teh mixture, the less bore wear there tends to be (and there's competing ideas as to why that happens. Some say excess fuel can wash away the micro film/layer of oil coating the bore and increase ring/bore wear. Other's point to the different combustion byproducts you get (in both type and concentration) with a much richer mixture. SO in other words, whilst you have to run rich under boost to prevent potential catastrophic damage/failure, at other times, under part throttle, it makes sense to run it quite lean. You'd still run richer - around stoich or a bit richer - for idle, just to get better idle quality (and there's a few reasons for that) but once you are up out of the idle or what might be termed fast idle range, true part throttle moderate rpm cruising - like suburban streets or even on a highway that is more or less flat - that's the operating range/conditions to try and run leaner than stoich.

BUt once manifold vacuum starts to drop off, let alone once you get into boost, you don't want to run lean. The additional fuel, as you go way above stoich (some people run around 12:1 or so for petrol fuels) isn't actually burned, it's anti-detonant properties are due to the cooling effect of the fuel trying to change into vapour/gas. This sucks heat out of the intake charge, so that teh peak temps after the piston has compressed said charge will be lower (since it starts at a lower temp). This cooling effect also results in a little more density, so you can 'sneak' a little more air in there at the same boost level and that extra air supports the combustion of some more fuel. Which is why pure methanol injection (in a water injection type setup) tends to have the highest power output for a given level of boost etc. On the other hand, water injected won't vapourise in the intake tract (well not much of it anyway). And it is when a liquid turns to a gas that it sucks heat out of whatever is around it to enable the change of state. So water won't help get that little bit of extra air in there. BUT the water will start to change state as the piston is rising on the compression stroke, and the intake charge in the cylinder is being compressed. So rather than cool it as such, it might be easier to think of it as preventing it from heating up quite as much on the compression stroke (and the piston compressing the charge is relatively less thermally efficient than a turbo is - it heats it more for the same level of compression compared to a turbo. It also (of course) compresses it far more - hundreds of psi by the end of it. Anyhoo, so the water 'goes to work' inside the cylinder. Which is why it won't make (all else being equal) as much power as methanol injection might, but it _also_ is a better anti-detonant - after all water doesn't burn at all, but methanol can. SO that's why what it does do better is that it allows you to run more boost on the same setup as you could with pure methanol injection.

Since we know that running richer helps stave off detonation when you get into boost territory through it's cooling effect, what you can do is replace most (but not all) of that additional fuel with water, and be as safe. Of course if you run out of water, of the pump fails, or the nozzle gets blocked, you can lunch the engine fairly quickly.


But back on topic, without knowing the actual turbo cam specs and the static comp ratio and the manifold design and what fuel you are intending to run, it's a little more difficult to make a dead on
prediction of power output, but what could be said is that you should have trouble going beyond 200bhp with that sort of boost level and 1.5 litres of engine

Obviously the other big factor is ignition advance. It wouldn't be outrageous to find that at that sort of boost level that total timing in the low 20s (or possibly even less than 20) would make the best power. More advance isn't generally a good thing with boost (unless the rpms were sky high) and is often counter productive.

Awesome man
Same setup as me but yours is finished!
Post some pics.
My delays are the little things now.
That and my 2dr sedan body isnt ready

What do use think????

Hey guys just picked up my engine, for my draw thru set up, what i got done to my a15. It's been balanced copper gasket o ringed e15turbo pistons  closed n hone rods all new bearings n custom can recoed head.... Bigger valve springs! Timing chain kit , ARP bolts and studs, electronic dizzy, etc etc

Yeah its a .64 clyson, would that be to big?

The T28 is a turbo, it is a larger turbo than the T25. There are some subtle differences to distinguish between the two.

The t28 and t25 share the same flange.

H165's are a terrific diff. Not unbreakable, but plenty strong enough. And replacement heads are easy to get. But locked, you might eat a few axles. Ute axles are a little harder to get. (Here at least anyways)

Aww okay thanks for that, do you a good carby people have achieved good power on here with?

Don't see why the h165 won't hold up, people use them behind ca18's.
I wouldn't worry about numbers so much just build it and see how you go but the carb will most likely be your limiting factor.

yeah its a .64