Whilst your friend's math isn't 'wrong' by any means, it does however come across as if he thinks it has to be a big dollar perfect match or it just won't work.

In real life, especially 'the ghetto' - you will find you can actually get away with a lot. fwiw I think you should be looking for another turbo - and if possible one off a nissan exa or et pulsar (same engine/spec afaik). I had one of them on a 3k corolla motor and got it into the high 14s (with absolutely EVERYTHING done wrong - smaller motor, crappy flowing pollution era head (you have a bigger motor, and a much better flowing head) and a j pipe that was nothing short of an abortion (the funnelling down from the twin outlet cast iron exhaust manifold was atrocious,the j pipe itself was 2 1/4 inch diameter - too big (slightly smaller keeps the velocity up) and the flange welded on the other end to mount the turbo to - since it had to sit over a 2 1/4" pipe (whereas a 1 3/4 or maybe 2 inch j pipe absolute max will be easy to gently funnel into the flange without an obstruction) - well it was like a big parachute, horrifically inefficient).

despite all that, it ran hard. If you ran a similar turbo on your a14 it would surely be able to run a low 14 without spending stuff all.

I'd like to make a point 'against' laggy turbos. Obviously it is all relative, so there's 'a little bit' of lag that might not be a problem, then ther is a ridiculous amount. as an example - in the US there were 2.3 litre 4 cyl turbo fords (mustangs) from about the mid 1980s. They were discussed a lot on the jyturbo list. Anyhoo, they mostly ran almost identical turbos, but some had 0.48 a/r exhaust housings and some had 0.63 a/r . the larger 0.63 ones produced more power, due to less exhaust restriction overall. However, despite that, on the street, the vehicles with the tighter turbo would always get a few lengths ahead (and maintain it) taking off from a standstill. The reason is simple enough - they spool quicker and get into 'big power' (relatively) sooner and start accelerating hard sooner. The others spool slower so even though they eventuall make more power, they spend more time 'getting into the swing of it' and get left behind so to speak. On the street, better spool (well not so tight on the exhaust that you can spin the motor up to 4500rpm or something!) will be king. It's not just good off the mark, but things like overtaking - the quicker you can access boost/big power the better the outcome. Another place you can see it is some of the 'flagships' of certain turbo workshops. They have a car - once upon a time the VL commodore was the big one here - that they have one of their top of the line engine/turbo combos in. And there's footage of it at the dragstrip and the car runs some absolutely exceptionally quick et/high mph. Which is admirable. But if you look at it closely, they are just running to get a good time (and remembering the 1/4mile et timer only starts once the car actually starts moving and breaks/passes the beam under the front wheels, so they can sit there forever and not be 'running up the meter') - and they'll often spend 5 seconds or so spooling the turbo up so they can launch optimally and run hard. that's all well and good, and whilst it produces a quick time, in a 'real' drag race, a car that spools better can launch harder (and in drag racing the winner is the first one to the finish) will launch, and beat the 'quicker' car to the other end. The 'quicker' car - the driver either needs to launch earlier (than optimal, but I don't mean red-lighting by leaving too early) and without full spoolup, and therefore run slower, just to get off the line in time. He could wait and spool it up so it launches harder, but all the while the 'slower' car is charging further and further away.

So how much lag (or lack of it) is acceptable or not. Well - it differs from engine to engine and car to car. Since we are dealing with smaller engines (that can handle ok rpm without much work) 'ok' spoolup rpms can actually be a little higher in the rpm range than a turbo you might put on a much bigger engien that revs lower overall. So that in mind, I'd suggest that if you can get it starting to spool just prior to 3000rpm, and getting to useful boost (or nearer full boost) by about 3500 you'll be pretty happy with the result.

I absolutely agree that e85 (or e-flex which I think varies down to around 75% at times, but don't quote me on that!) would be perfect for this. But if 98 it has to be, then it's still going to get a good result. Water injection is your friend, and works exceptionally well. You can read about early work on water injection if you look up 'naca reports' (NACA was the forerunner of NASA, and was a tech/research sort of thing for all things aircraft development related). They tested various engines (often to destruction) with higher and higher boost levels and ever increasing water levels. water injection was used on ww2 fighter aircraft (when combined with higher than normal boost levels, for short during emergency high power for stuff like dog-fights) fairly extensively. They (NACA) went as far as actually exceeding a 1:1 ratio of water to fuel (i.e. for every litre of fuel being fed into the engine at full boost/power, they actually were feeding in MORE than 1 litre of water) - and it was still effective up at those levels. On most automotive applications, you'd rarely find anyone going beyond maybe 4:1 (for every 4 iltres of fuel used, and yuo can calculate that based on power output - anyhoo for every 4 litres of fuel, 1 litre of water is added).

They say you need a richer mixture under boost to help prevent detonation. This is certainly true. what not everyone knows is 'why'. It's not because the fuel burns dramatically differently. Run richer and there's going to be some unburned fuel going out the exhaust. It's actually the cooling effect of the extra fuel that cools the intake charge a little bit that helps prevent detonation. This is where it gets interesting. Since it is the cooling effect, and testing has backed it up 100%, well if you added water injection, then that water could take the place of the extra fuel, and it would take care of the cooling effect. I'm not suggesting you should lean it out way too far and then run water and hope for the best. What i am saying is that instead of (hypothetically) going as rich as perhaps 11:1 as you run more and more boost, you could run around 12:1 a/f ratio and add as much water as is needed to handle whatever boost level you are going for.

Bruce Lees favorite drink?..... WHAAATAARH!
The owner of the crude turbo A15 in a vb10 1000 wagon runs a very crude windscreen water unit setup into his draw through as it gets atomised perfectly in the turbine.
His Log style manifold setup gets up to 30psi but cant find his username atm.

Whoa awesome reply thanks John
D - I'm going to investigate water injection once I have it running ok and im in the tweak phase.

John I also agree with your logic with regarding getting spooling happening by 3k and near full boost by 3.5k

So you think the nissan exa or pulsars turbo would achieve that?
And if I wing it with the s13 t25 sounds like that will be more like 4-4.5k?

How hard is it to adjust/change inlet and exhaust manifolds if I get it made for the s13 T25 and wanna swap turbos down the track? Plasma cut & weld new flange?

I had this idea for a while but happy to share it as ive got them coming out everywhere usually, this is what I've planned for my 1000 manifolds. Its a shorter version of the Log style turbo manifolds most peeps have used and probably cheaper again and nicer than a J type banana one. Cast iron mani will be heated to 210 degrees then brazed with bronze for the steam pipe which both have similar heat porosity and qualities as cast Fe. The turbo will sit on top of the heating opening with a laser cut flange to suit a GT1544 which has the flange facing right way etc. Will just need 90 degree tube to fit extended customised stock inlet mani inlet manifold has to be extended with custom small plenum but flow remains equalised.
Even though it all sits higher than usual setups it will clear most engine bays like tiny 1000 & still manage to fit SU carb perhaps a shorter height HIF6 or compact Stromberg cd175 (Rover V8) etc.

eg.






Its ghetto as cheap but should be good enough for a clean compact setup that wont cost the earth & can be upgraded to nice turbo ex manifold later. Maybe a flat plate can be welded underneath ex mani for extra webbing strength.

What do you guys think of my Supremo Favela manifold ideas?

D - Is it possible to provide a quick link to an underbonnet pic of a datsun 1000 to show how much (or little) space there is and where the space is?

I'm making the assumption that you're particularly limited with space, but actually now that I think about it the a15 turbo you mentioned is in a 1000 wagon is it not? (I've got the video of it somewhere - a collection of pics with music from 'the spazzys' if I recall) - so there is some room for a lower mounted turbo.

Among my concerns would be the amount of heat radiated to the intake manifold (I'd also suggest you'd need to look at special paint on the bonnet directly above the turbo, on both sides (the garret drawthrough kits for toranas from the late 80s weren't quite as close as I imagine this design would be to the bonnet, and they'd eventually start to affect the paint. Certainly it wouldn't be outrageously hard to make up some pieces of sheet metal heat shielding (possibly out of stainless) and or that heat wrap tape (it won't survive around the turbo itself for long, but you could also wrap the intake manifold itself.

I'm not a big fan of the factory single carb intakes at all. I just don't like their relatively sharp turns (both under teh carb to go fore and aft then the turn 1&2 and 3&4 respectively and of course the very very late split from single runner out to each intake port.

If you look at the firing order, 1 3 4 2 it's also 21 34 if you think about it. That means it has an intake cycle like this - front front, rear rear, So if you feed 2, then just as it closes, 1 is about to be fed. From a common snigle runner. It's not as bad as something like a mini head, where even the port itself is shared, but it does mean that it would be emptying that runner then needing it 'full' to feed that next cylinder. Then there's a big gap as the rear two have their intake event. I'm thinking (and this isn't scientifically proven fact, just me thinking out loud) that having longer individual runners, under boost at least, means you can have the intake charge stacked up and waiting and it'll possibly get just that little bit improved cylinder filling when each intake valve opens, at technically the same boost/rpm level. The turns (and the Y shaped split near the head/manifold face of the intake manifold) are also less gradual than I'd like and i think it would lead to some degree of mixture distribution variation, not a good thing on a turbo setup.

The 'good old' log style intakes - if properly put together, alleviate almost all of this. Firstly, they can have a long (gently curved and partly if not mostly downhill) transition from the log section to each port. A curved runner per port means there's less likelihood of intake charge robbing from the paired cylinders. There is the slight 'uphill' journey to the log itself, but it happens immediately after leaving the turbo, where the mixture will eb at its best, and less (if any) fuel is likely to drop out of the flow. Extending the 'log' section a little bit further forewards and backwards past the edges of the front and rear runners is also good, it helps flow (a little bit) and arguably the shape actually leads to some amount of turbulence (not detrimentally) and this helps to prevent the suspended fuel droplets (tiny as they are) from falling out of the flow. Since the runners are downhill from that point, even if there was a tiny amt of fuel dropout, it won't 'puddle' into a small lake somewhere in the intake, it'll move into the cylinders (and since it'd be moving fast, it'd never build up or anything) that will remain there until the next time you floor it and the flow velocity is up and the mixture is better suspended etc . SO no flat spots/black smoke on the resumption of increased throttle openings.

Just out of pure coincidence, I've been thinking/looking into possibilities for manifolds. Obviously twin webers are the go for NA performance etc. But I was looking at the intakes on early corolla (the 3k and 4k motors in particular) engines, and looking into if I could copy the idea and turn it into an intake for a datto a-series engine.

http://www.rollaclub.com/wiki/images/3/37/Bigport_bent.jpg

http://www.rollaclub.com/board/topic/ ... ge__p__468972#entry468972


The basic idea would be that it would actually be a much better intake, as far as single carb setups go, than we can currently source for our dattos. They basically have a similar sized plenum, but the runners (on the better of the toyota variants) are separate from the plenum to the intake port in as gradual a C shape as is possible. If I could adapt that to an a-series (actually it'd have to be made from scratch, since the toyota runner dimensions are too small in diameter to work with an a-series - esp an oval port one. Might be able to adapt/use the original datsun plenum with a few tweaks.

FOr a single carb setup, this could work well I think. Additionally one could even experiment with putting a dividing wall inside the plenum, so that 1 and 4 are fed by one carb barrel, and 2 and 3 by the other (it would mean needing a 2 barrel carb where both throttle plates open at teh same time and each carb barrel is the same size) - sort of like a 'dual plane' manifold for a 4 cylinder (they tend to help midrange torque on v8s etc, couldn't hurt to try it , and the divider itself could be made to slot in or be removed practically instantly. And the carb I'd suggest would be a holley 2 barrel. As much as they are the 'fisher price' carby, they typically aren't hard to get a great idle and good power out of even on a smaller engine like this (in hindsight it was one of the few things done right on that turbo corolla - running the holley 2 barrel). And to follow on to the next step - the holley carbs are about the easiest to convert to run in a blowthrough configuration. I realise this thread is more drawthrough oriented, and there's nothing wrong with that at all, what I am saying is that if I was going to even attempt blowthrough on an a-series, personally I'd be making my own intake along the lines detailed in this post. If I couldn't run a 2 barrel holley on a 4 runner intake manifold, I'd honestly go with drawthrough - or put another way - I'd only run a blowthrough setup if it used a 4 runner intake manifold.

Again, in all fairness, there's enough people who have run blow and drawthrough setups with factory style intakes and gotten great results. Sure for all out racing, it's a situation where (potentially) 1-2% power differences can be the difference between winning a race or not even finishing in the top 10. In those cases you need it all - minimal lag, high power, high power across a wide enough rpm range, the most power possible for each and every oxygen atom you can get into the cylinder, etc etc etc. And for thatr application, you have to do it all - efi, well matched turbo, optentially aftermarket ignition, both intake and exhaust manifolds fabricated to optimise each, you name it. But on the street, where you aren't restricted by any rules(like having to run an intake restrictor that limits flow, engine capacity regs, etc) and where you aren't trying to send world records, well you can go a little more conservative - get the boost in there however you can - if you can afford a custom intake and exhaust manifold, do so, but if not, the j pipe exhaust and a factory intake is still going to get you a darn quick car

Yep all correct in regards to the datto wagon with spazzy music

There is room for lower mount turbo setup but the idea I have is
to simplify the inlet and exhaust manifold to make it as compact
as possible yet still some distance from the bonnet for if you add
the carb sitting ontop of the normal manifold and air filter it
should leave about 10cm of space above and all thats needed is
some steel plate over the turbo or some heat proof shield with
insulation on the bonnet also to avoid buckling.
Although the inlet manifold has less volume than the exhaust it
should provide very good response.

Datsun engineers where quite smart with the inlet manifold in
having the Y split it focuses the inlet charge towards the inner
sides of the V compressing the flow in a tight "0" like shape that
would push the charge into the cylinder through the outer edge of
the inlet valve wedge wall improving centralised swirl.

Although not the best design for overall NA power with boost its
a different story where swirl type heads are improved with boost.
I have thought of using the big port 3k manifold from the toyota
however they are alot of work and not equalised lengths which do
upset the pulses compared to our beloved A series manifold.
it should like TopGears Draw through provide nice response.
The small inlet manifold volume should have no puddling.

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Trust me, the difference in runner lengths won't be any noticeable issue. It won't upset the pulses (esp since if you look at 'where' they draw from, it actually gives an even gap between when each runner breathes if we make the (admittedly not quite accurate) assumption that 1 and 4 breathe mostly from the outer barrel, and 2 and 3 from the inner. In contrast, the 'single' runner of the datsun manifold (front or rear) gets 2 pulses in a row (in fact potentially with some overlap if cam duration gets long enough) then a big gap before the next 2 in a row.

Having said all that I don't think there'd be enough difference for anyone to lose any sleep over. The main thing (and this is oversimplifying a bit I'll admit) is getting the air/fuel into the engine and the more you get in (assuming you can burn it properly, so a strong ignition etc) the more power it would make. A 'ghetto' turbo setup with less than perfect cam specs, less than ideal manifolds etc, well it might take (and these are figures I'm pulling out of thin air for sake of discussion) 14psi to make the same power as another a14 or a15 with ported head, really well specced cam, better manifolding etc might make with only 10psi, but rest assured it will still make the power.

In terms of welding cast iron manifolds, it's certainly doable. Definitely pre-heat both manifold and new flange section to practically red hot, then you can stick (or arc, depending where you are, some people call it stick welding, some arc, and I have no idea what else!) weld it. You can get welding rods for arc that are specifically for cast iron. There's usually 2 types (broadly speaking) - one is a little more 'flexible' and less likely to crack, the other type is a bit more brittle, but tends to be easier to attach to dirtier cast iron. I'd suggest cleaning teh weld area as well as can be so that the more flexible rods (and I know I'm murdering the proper terminology for this!) cna be used. I'm also aware of some people (one I've seen in person, and one I've seen online on another forum, by a regular poster there, I'll try and dig up the link if it is still there)have used welding rods meant for stainless steel and had similarly good results. Again the 'big' deal is to pre-heat a hell of a lot, then weld small lengths (perhpas 1 inch at a time or so) then peen it to help stress relieve it, and then let it cool VERY SLOWLY (or leave in the heat, and give it some time then weld the next bit). Done right and it'll last a long time.

Another 'trick' related to it is - since the flange to bolt the turbo to will be steel rather than cast iron, it is sometimes hard to get it to 'stick' to the steel. In this case the trick is simple, run a full bead of weld around the 'bare' flange where the cast iron manifold is supposed to attach, then put them together and weld them, so you are sort of welding the cast iron manifold to the newly added weld on the flange, not direct to the flange itself.

STill on a related note, I'd go even further. On the old garret drawthrough setups, they ran a custom cast iron exhaust manifold (custom alloy intake too, but that's not relevant here). And over time, with heat cycling they'd start to warp. So some people would try doing them up tighter but they'd tend not to seal at hte manifold face. No big deal. Don't overtighten, it'll only lead to them potentially cracking. Instead 'plan' for this to be a likely outcome, and around 1 month or 2 after initially getting the turbo setup running, unbolt the exhaust manifold and check for straightness, and if it is warped, then machine the manifold face back to flat. After that it will probably have warped as far as it is ever going to (or maybe if you were very unlucky, you'd have to repeat this step another month down the track) and after this final machining, it won't warp, and won't crack because it's been bolted down hard to try and seal the warped face, which puts it under pressure and invites cracks to occur..

Similarly, make sure any bolt holes/grooves have around 1mm clearance, It mrans you have to be careful lining up the manifold, but it does give ti the chance to expand just a little without the manifold boltsjamming it up and again inviting cracking of said manifold.

what else - a tip I picked up from the old blowthruturbo email list (which is now called 'carbureted blowers' on yahoogroups and has been dead for literally 4-5 years - but has massive amts of info in the message archives going all the way back to the mid-late 1990s when it was at its peak) was this - turbos weigh a bit, so the weight of the turbo itself can be a strain leading to cracked exhausts. So the trick simply was to run a steel bar with holes in each end, and bent at each end to suit the bolt locations, and it allowed this bar to go from a manifold bolt to one or two of the turbo to flange bolts and therefore it'd act as a support beam and take a decent amount of the total weight.

I definitely think an e15 turbo (nissan exa/et pulsar) would be the go and would suspect it would spool up even quicker than the approximate goalposts I suggested in an earlier post. I base this on my own experience (got full boost by 4000rpm, but remembering the exhaust was as bad as can be) but also on the nissan exa specs themselves. It was a 1.5 litre engine same bore and stroke as an a15 (and same bore but longer stroke than an a14). they made peak torque around 3200rpm (and I looked this up to help clarify things, I don't have a photographic memory!). Now there's no way they'd make peak torque 'off boost, so to make peak torque at 3200rpm it stands to reason they were spooling up earlier (perhaps 2500rpm?) and were at or very near full boost by 3200rpm. Not a bad thing at all, and would be similar on an a15, or perhaps starting to spool around 2600-2700 and full boost (or close to it) by about 3400rpm .
They made about 115bhp from memory, which would (to me) suggest you'd be able to get around 150bhp from them before they got ridiculously out of their compressor side efficiency. (mind you I wouldn't be wanting to try and find 180+ from said turbo). This is certainly backed up by how quick it ended up on the corolla I had, based on it's performance, it would have had to have been making around 150bhp. Considering how bad the exhaust setup on it was, it's probably fair to say that it killed off a good 10bhp extra (or even more) due to exhaust pumping related losses - in other words the same boost on the same setup with a better exhaust j pipe (and remember there's nothing wrong with a j pipe, just that in this case the particular j pipe that was run was absolutely craptastic) would make more power, just because it isn't being robbed by the exhaust restriction/issues.

another couple of turbos to consider - one from a ca18det. A touch on the large side but certainly workable. And one of the turbos off a late model 300zx - the twin turbo vg30dett engines. They are twin turbo on 3 litres producing around 210kw . In other words each turbo caters to 1.5 litres and 105kw (about 140 bhp) so getting 150-160bhp out of one of _those_ turbos would be easty and in general they'd be a bloody fantastic match.

I've used a CA18 T25 drawthru on an A12 before on a mate's street/track 1200 sedan for U2L class hillclimbs and sprints. It was a good match IMO, even as a street setup. I did alot of the setup and tuning on it and alot of road testing - it would make boost in 4th gear at 60kph to keep you going up very steep hills without needing to downshift. So the boost threshold was pretty good, without strangling top end at all. It would be better again on an A14 or A15.

Some good points on machining after a few months of heat cycles
bracket for extra support is a given and what I have used for
cast iron recently is brazing using the Oxy successfully.
Brass is not cheap but cheaper than high Nickel based rods that
are usually avail for this kind of mods.

I would make the exhaust manifold as small capacity as possible
using a bigger than logical turbo to make sure it spools faster
for the street where Logs are enough below 6500rpm redline.
For racing where the upper rpm is needed equal length are king.

Just for comparison a G13B suzuki gti motor is using a T28BBRS
E85 22psi for 220kws, thats 1.3 litres but nothing below 3500rpm.

So...
Things have escalated A LOT.
From slap happy junkyard turbo build I now have the A14 in the machine shop with the following parts on order:

1 set (4) turbo dish pistons 0.5mm - (that need mods)
List 1 set - chrome rings 0.5mm
1 set - std main bearing
1 set - std conrod bearings
1 set - std cam bearings
1 - h/p timing chain
1 - chain tensioner
6 - welsh plugs
1 - can blue paint
1 - full gasket set
1 - 0.6mm race head gasket
1 - ARP Head stud kit
1 - ARP conrod bolt set
1 set of (8) H/P double valve springs
1 - oil pump
1 - offset dowel kit (for dialing in cam)
1 - re-reground turbo cam
1 set of (8) re-faced lifters
1 - water pump

Also now have 2 turbos off a R32 GTR skyline, and one is being rebuild with a carbon seal and steel exhaust wheel.

Cars are a really #OOPS# game, this was supposed to be a budget build!! :-/