32/36 will not make even 170hp atw you best use a sidedraft weber 40mm, Holley, correct 2 inch SU or Harley Davidson replacement Ultima carb with 50mm opening and extra nozzle for meth or nitrous :).
The ultima carb has quality brass float all ready for E85.
http://www.ebay.com/itm/Ultima-R-1-Pe ... Replacement-/130917555708

Hey Ive just seen this thread and wanted to share some experience. I have a A14 Turbo at the moment and just built a fully worked efi motor. I started with a 350 Holley blow through set-up with WRX TD04 Turbo and 10psi. the sound was unreal and i was happy with the power. Only the head and manifolds were worked + electronic dizzy and copper head gasket. As far as i knew the bottom end was standard with low kms. (when i pulled down the motor i discovered they were 1500 pistons)

What i found was it was rough, cough one day, stall at the lights the next then run smooth the next time. When i got sick of doing that, I hunted down an A Series EFI Manifold and got it with aftermarket computer. What a difference it made!!

It didnt sound as good as the Holley but when it boosted you couldnt hear the motor anymore anyway. It made it smooth and consistant power and reliable to drive. i got the handset to make a few adjustments and on the dyno she went. i got 100Kw around 132hp atw.

That was 2 years ago, before xmas last year i had damaged a piston ring and thought time for a rebuild. This time i had a set of oversize 1500 semi forged pistons fitted with a balanced bottom end stage 2 turbo re-gound camshadft and oversize head studs. With a little more boost im hoping for around the 180hp. Just running it in now.

If your looking for a set of E15Turbo pistons drop me a PM i have a new set with rings available. Iam still a fan of webbers (i always will be) But unless you know a old school mechanic or know how to do it yourself i would recommend efi.It stays tuned and more power too.My manifold, injectors, loom and elec dizzy was off an A series and i paid $2000 for the lot.

Hope this info helps

The following is just a bit of personal experience/thoughts and is in no way 'the last word' on anything. It is also DEFINITELY NOT a suggestion that x y or z must have been wrong with Big D's holley, or that he was responsible for damage to it or anything like that. Carbs are mechanical devices and see a hell of a lot of fuel passed through them over time. They can break, or experience material deposits or whatever - given enough time. It's just the way it goes.

I'll also say this - some of the work discussed below can make sense for people diy-ing the whole thing if they have teh experience (and time, and ability to put up with a heck of a lot of frustration if something does actually go wrong). BUT getting the work done by someone else starts to add up quickly in terms of $$ cost. And all the time, efi setups are getting cheaper and cheaper (and cheap doesn't have to mean poor quality either!) . So whilst I happen to be pretty good with carbs and just 'like' them, I couldn't make an argument totally in favour of them. At least not for all cases, and with each passing day, as prices drop for EFI and either maintain or increase for carbs (speaking about cost to get a carb worked on by a professional, not the purchase price of a second hand carb). Anyway, on with the actual reply!

I've got some experience with a (apologies for mentioning lesser cars!) 3k toyota corolla and blowthrough turbo. I ran a 350 holley. Absolutely couldn't fault it. It ran flawlessly, idled smooth as silk, and under power, did all it was supposed to.

BUT, there's some BIG issues with 2 barrel holleys. Second hand ones at any rate. The biggest is that unlike the 4 barrels, which have full support for the air cleaner base, the 2 barrel holleys only have one half of it supported underneath then there's a big 'tray' section that is half the air cleaner base, with 'nothing' underneath it. What happens is that over time, with the air filter casing being tightened down (esp if someone goes too hard there) it warps the base. Then it won't seal. then they try and tighten it more and it gets worse and worse.

I haven't looked lately but in the past I've seen a bunch of 2 barrel holleys on ebay (for example) and about 1 in 3 showed significant warpage as discussed. And another few of them, either it was 'luck' or the seller had worked out some creative camera angles, but really close scrutiny of the pics did show the same sort of warpage. This can cause other issues with air leaks or similar.

The second big thing - apart from the 'regular' 350 and 500 holley 2 barrels (and ignoring the 'other' holley 2 barrel which is basically a licensed copy/clone of a weber - I think the 32/36 dgv, but don't quote me on that) - well apart from that there's also the holley 320. What this is, is where holley took a regular 350 (or started with that general spec to build upon) and modified it for better emissions and economy. They have much different booster venturis (they look like some sort of ww1 aircraft machine gun cross hairs! from the top) which are more sensitive and give better signal strength (which is not always a good thing, it's all about 'appropriate signal strength, otherwise it can end up wanting to go way too rich as you get nearer to the carb's max airflow) They also produce a finer fuel droplet size for the main fuel metering. . they also take up more space in the carb throat (for want of a better term), and this ended up reducing the carb's flow rating to 320cfm. The other change (there are more afaik, but these are the key ones) is they have revised metering blocks (which are like a self contained unit that has the equivalent of a weber/dellorto emulsion tube and idle jets etc etc). Apart from being more economy suited, they have a revised idle circuit. And on the 320 to lean the idle you turn the screws the opposite way to all regular holley idle mixture screws. They also have a narrower scope for adjustment.

Shorter version - be careful to avoid the holley 320 altogether, and if buying the 'suitable' holley 2 barrels second hand, make darn sure that the air filter base section of the carb body is dead level and not warped/damaged....

There are other things that can go wrong too. Dirt and debris can find their way into the various circuits. Even with a fuel filter, since sometimes it can literally come from tiny bits of paper gasket when the carbs are taken apart and reassembled. There are little plugs/seals on the metering blocks (usually look like very tiny welsh plugs (aka freeze plugs I think in North America??). They aren't easy to get out and I wouldn't advise anyone new to carbs to try it, I'd suggest either getting a quick helping hand from someone who has done them before, or alternatively if you happened to have a 'wrecked' holley (maybe you acquired one of the stuffed 2 barrels that was warped, which is what I used to work things out for myself some years back! so I certainly learned the hard way about buying second hand) you could use the metering block off that stuffed holley to get the plugs out, see what is behind them and then being able to work out how to get them out of a 'good' metering block without damaging them. I wouldn't say it is '100%' safe bet, but often when holleys start to run inconsistently and all other usual suspects (the stuff easier to see/check ) have been eliminated, debris inside there has to be a strong candidate.

In general holleys come with a couple of types of floats. THe first 'difference' is where they attach. Some attach to the side of the fuel bowl. The others attach to the front/centre of the fuel bowl and the latter is called 'centre hung' floats. Definitely the way to go for peformance (they tend to be less affected around corners than side hung ones).. The next key difference is what they are made of. The 'brass' ones are as the name implies thin sheets of hollow brass stamped into a shape and soldered (or whatever the term is) together. They are the weakest. A single big backfire and they'll collapse or implode and typically jam so that they never close the needle and seat and the carb floods as the fuel bowl overfills. They will also collapse in a blowthrough if there's enough boost (I reckon 10psi would be a very big ask of them, but haven't personally tried to test their exact limit. On other carbs like that, you can drill a couple of holes (one to let it in, the other to let air out so it can actually keep feeding the stuff in) and squirt in rapid expanding foam (the regular hardware store type) and reseal. This will support them and they will work. HOWEVER for holleys there is no need. The second type of float is made of white semi see through plastic, and called a duracon float (iirc). A bit stronger than brass, but they too have their limits. The third type is a hard black plastic and these floats are built tough. Probably 15 years ago one of the guys on the old blowthruturbo email list put them in a chamber and pumped the pressure up to 60psi, and they still didn't collapse, even after being there for hours. So they are just the ticket for blowthrough and available off the shelf for holleys. They are called 'nitrophyll' floats

AT about 15-18psi, the engine will be taking in literally double as much air as it would with the same carb but in NA form, no boost. Which means it will require about double as much fuel as that size carb would normally have to supply. So you 'can' get to the point the stock needle and seat don't flow enough (to be fair it's more likely on a 500 on a slightly larger engine and higher boost but just for the sake of covering all bases, or as many as I can remember). you can get 'alcohol' spec needle and seats (since running methanol requires nearly double the amount of fuel in non turbo form, as the same engine with the same carb running on petrol) which flow a lot more.

With the 350 I ran on the corolla, I got fairly lucky. It came from a workshop where they used to get in a bunch of carbs and reco them for sale. I happened to get one that they had stripped and cleaned, but hadn't reassembled/set up. So I got it cheaper. I added the stuff it needed (reusable metering block/fuel bowl gasket, regular base gasket and a nitrophyll float etc) and away it went. Naturally there were jetting changes to get it where it needed to be, and some work on the accelerator pump (different cam and squirter ended up going on there).

There's another mod which can be quite useful. As is fairly well known, the more air flowing through the venturi, the stronger and stronger the signal to the main fuel circuit. But it doesn't go 1 to 1 - i.e. the flow goes higher by 20% (for example) but the signal strength goes up 30-40%. So left 'as is' the carb would run somewhere around lean or stoich at lower rpms/flows then richer at full throttle mid range rpms, but by the time it got near peak rpms, the mixture would be way way way too rich. So to combat this carbs have a small port/vent that allows some air to be bled into the main fuel circuit fuel flow and as fuel flow goes up it's easier to 'pull' on the air bleed than the fuel, so as signal strength goes up, it pulls more and more air in, and by sizing that hole just right it will basically allow it to maintain a consistent air/fuel ratio across the upper rpm/flow/throttle position range. Those holes (which are usually a type of jet - just one for air not fuel) are called 'high speed air bleeds' on holleys and 'air correctors' on weber/dellorto carbs. Since we know what they do, a nifty trick for blowthrough turbo - you run jets that allow you a reasonable part throttle a/f ratio, then the power valve opens to provide a little bit richer mixture with higher throttle openings (if fitted. Some people run a power valve block off plug as they can occasionally rupture the power valve which leaves them open all the time making it too rich at part throttle) But under boost, you generally chase rich mixtures, a fair bit richer than a non turbo engine likes for full power. SO the trick is simple, reduce the size of the high speed air bleeds. Then they don't level off the mixture as much and it 'almost' goes richer and richer as it sees more boost. As a rule of thumb you'd want to look at reducing their _area_ (area, not diameter) to about 50%. That is as close as makes no difference to reducing the diameter to about 70% of its current area. On some carbs you can fit screw in bleeds (and the holley 2 barrels can be modded to take them) but another trick is you can get fine fuse wire or piano wire and feed it into the hole to reduce the effective area (you can drill small holes in the choke 'horn' section of the carb upper body section so you can 'tie' the wire there so it then drops into the bleeds but can't work loose and be sucked into the engine.

One thing I'm not super keen on is the stock datsun intake manifolds. the single runner going to a Y just before each pair of intake ports is my focus there. The toyota intakes have curved runners all the way from the carb/plenum section in the centre, one out to each port. Now obviously the toyota ports are smaller, and the heads typically don't flow as well, so they have their drawbacks too, but ideally if I was to run a holley on a datsun, I'd actually custom make *(possibly using a few toyota K series intakes to cut and modify and make larger/oval from top to bottom on each running) a manifold based on the overall layout of the k intakes, just sized to suit the datsun ports. I've mentioned this elsewhere in another thread. It'd be a labour of love, hardly cost/time efficient at all to do such a thing. I bring this up because that's another big advantage to efi - or at least presumably so - which is to say you'd typically run an efi style intake manifold - either a big single plenum or IR - either way would have less obstructed (or 'shared') intake runners like the stock datsun carby manifold has.


Anyway, enough rambling from me.

Big D has the crossover nicely built manifold and what I remember you did use a round port head at some stage? love that stainless steel manifold.

The Holley 350 is used by VW guys very successfully but to make 170-200hp atw I still question their reliability at those boost pressures for an A15 but you never know unless you try and different atmo, fuel quality & temps could have issues?

ok for high boost? I ran mid 20s for a while (eventually blew the head gasket and took a chunk of the head with it) - the carb itself had no trouble with it. If size was a concern you can also look at a 500 2 barrel (and remember that the 2 barrels are flow rated at a different pressrue drop to the 4 barrels so a 500 holley is actually about the equivalent of 350cfm on the 4 barrel test pressure drop)

Wow Jmac some useful info there mate some great experience.

Hey D, very happy with the upgrades i must say. Na the port was always oval on my manifolds, with the blow through i had a 350 holley adapter plate welded to the inlet and then ported out as much as possible. then the 350 holley (7448) bolted straight up and i used a planium off a valiant that came with a holley standard. It was a match made in heaven and looked really nice and neat. The only thing was (good or bad) it sat a little to high and i couldnt close my bonnet so i was forced to cut a hole and use a offset bonnet scoop. I like it but the cops diddent.

BigD confused you with someone else who did the over the rocker cover stainless steel manifold on a round port head with turbo efi he is getting 100kwatw! however any pics of your current setup?

Mate i took very little pics of the new motor being fitted. whats below is all i have. A 30sec video of running in the camshaft on start up that was it.(video Not attached) I would be happy to take a few pics of the specific motor set up on my next monthly visit to sydney. The old girl is resting till i arrive

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