MazterDizazter Posted December 7, 2007 Share Posted December 7, 2007 So I've been thinking (dangerous idea I know) about doing a carbureted turbo setup. If anyone has seen or read Wangan Midnight they may know about the carbureted twin turbo L28 S30Z. Whether or not that was based off a real motor is beyond me, but it got me thinking: could I swap in an L28ET and use my current triple Weber carbs with a custom plenum? I'm sure tuning would be a friggin' nightmare, and the other concern is whether or not the carbs could handle the forced induction. I saw the custom ITB's on extrudabody.com but they cost as much as my Webers and I really don't have that kind of money. So, is it doable? In my head it sounds like it's probably a bad idea, but I figured I'd ask. I tried searching but didn't have any luck... Quote Link to comment Share on other sites More sharing options...
nismopick Posted December 7, 2007 Share Posted December 7, 2007 So, is it doable? ANYTHING is doable... with the right amount of knowledge, time, and money. What you should be asking: IS IT REALISTIC? IS IT WORTH IT? Quote Link to comment Share on other sites More sharing options...
MazterDizazter Posted December 7, 2007 Author Share Posted December 7, 2007 Well I know it's doable, since HKS made a plenum for such a setup. Has anyone on here done it? Quote Link to comment Share on other sites More sharing options...
SHO-Z Posted December 7, 2007 Share Posted December 7, 2007 Do a search there is alot of information on what you are looking for. You could be reading for hrs on the subject. I am working on tripple SK racing supercharged set up. TonyD has the most information on turbo carb type of set ups. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 7, 2007 Share Posted December 7, 2007 Watch Wangan Midnight again. The engine STARTED as a Carb Blowthrough. By the end of the movie it's ITBs and Fuel Injection. The car is real (was) done by SSS. Search and ye shall find. I'm surprised it hasn't hit the tool shed, as this one is covered extensively. Quote Link to comment Share on other sites More sharing options...
MazterDizazter Posted December 9, 2007 Author Share Posted December 9, 2007 Alrighty, thanks for the help guys. I haven't seen the original movie; I was referring to the anime. Mods can delete this thread if you need to clear up the space. Thanks! Quote Link to comment Share on other sites More sharing options...
510six Posted December 9, 2007 Share Posted December 9, 2007 http://www.theturboforums.com/smf/index.php?board=13.0 should answer carburated turbo questions. http://www.cbperformance.com/default.asp CB performance is a VW place, but they are tops at modifying Weber Carbs for blow thru setups. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 10, 2007 Share Posted December 10, 2007 CB was vending Dellortos for a long while since they have specific turbo-application emulsion tubes, as well as seals for the throttle shafts. OEM fittment on the Maserati BiTurbo (Dellorto). For OEM driving (period correct) I'd find Dellortos and get the book "Turbomania" sold by Claudes Buggies (CB Performance)....it may disturb some, it knocks a lot of myths out of the Blowthrough Carb setup.But keep in mind CB now sells EFI for Turbo Applications for a reason... Quote Link to comment Share on other sites More sharing options...
Gareth Posted December 10, 2007 Share Posted December 10, 2007 IIRC, Dellorto once made turbo-specific DHLA 45M carbs (they were additionally sealed, jetted for a turbo application, and came with a fuel pressure regulator that adjusted the pressure as the boost came up), used in the Lotus Esprit 2,2 Turbo. They sometimes pop up on eBay.co.uk, I'd suggest you to check there. Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 10, 2007 Share Posted December 10, 2007 Yes, the BiTurbo and the Lotus were two Blowthrough OEM applications. I used Maserati Bi-Turbo as it was notably mentioned by CB. The Lotus used a lot more boost than the Maserati. WooHoo! All the parts for the Dellorto DHLA in turbo service are suitable for fittment to the N/A DHLA for conversion to the Turbo Service. Quote Link to comment Share on other sites More sharing options...
MazterDizazter Posted January 18, 2010 Author Share Posted January 18, 2010 Digging this up again... Yes, i just read up on those DHLA 45M's, pretty interesting. Either way I don't think my Weber 40's are going to be up to the task. 45's perhaps. I read elsewhere Tony_D stating that most driveablility issues stem from poor plenum design, i.e. being too small, like the Cartech manifold. I've considered fabricating a custom plenum similar to one used on 310z's car: I'm also hoping the thinner carbon plenum would allow a little of the carb sound out, unlike the cast aluminum plenums; the sound is a small part of the reason I wish to keep the carbs. Found this great site on blow-through setups: http://www.dune-buggy.com/turbo/carbureted.htm Found this issue (on above mentioned site): Fuel Enrichment: Your carburetor does not take into account boost pressure when it supplies fuel to the motor. Because of this you must take certain steps so that it supplies the correct amount of fuel when the turbo is at the maximum boost level. What most people seem to do is to jet the carb so that at max boost they have enough fuel. The problem with this method is that the engine will run rich at lower than max boost pressures which is also where most of your driving is done (As mine will be a dual-purpose street and track car, jetting the carb for strictly WOT operation is a no-no for me). A better method is to use a carb with a power valve and reference the valve to boost pressure. That requires possibly drilling some holes and running some vacuum lines. (Assuming the DHLA 45M has such a valve?) The other alternative is to use external means that can overcome the inability of the carb to understand boost pressure. These fall into two categories, a "dumb circuit", and a smart controller. The first type of circuit uses a pressure sensing switch to open a fuel solenoid. The fuel then sprays into the intake through an orifice. You set the pressure switch at what boost point you want the fuel enrichment to occur. As you can probably guess this system will not properly meter the fuel flow but it is better than nothing. (This won't cut it either IMO) The smart controller is an advanced electronic box that has the capability to meter the fuel flow depending on how much boost the turbo is giving the engine. With a "smart" controller your fuel curve will more closely match the air requirements of the engine and allow you to jet the carb as you would for a normally aspirated engine. The inexpensive ($150) Tim Systems controller pictured below works much like a mini fuel injection system. You use a regular fuel injection pump, 1 to 4 injectors, a pressure regulator, a MAP sensor and inject the enrichment fuel of your choice. Contact Tim at Tim Systems for more info: timsys@msn.com (Adding injectors to a carbureted turbo? That's defeating the purpose!) Now before you say anything, I know that the blow-through turbo setup will never be as good as a proper EFI setup. I know! But then again, we could easily argue that no matter what you do to your beloved L-series, it will never stack up to the superior RB25/26, so why aren't we all putting RB's in our cars? The reason I wish to do such a thing is simply because it's uncommon, at least for the Z car (I've seen plenty of domestics running blow-through turbo V8's, and of course there's the turbo Esprit and all those Vee Dubs). Maybe it's the desire to prove everyone wrong? The more naysayers I hear, the more I want to do it! I'm dealing with a similar issue in my supercharged MR2: everyone seems to think that 200whp is impossible without swapping out the stock blower for a twin-screw or a turbo. in any case, I'm gonna keep on researching and planning... stay posted if you like! Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 18, 2010 Share Posted January 18, 2010 Dune Buggy dot com is usually a good site, that the totally neglected the modulator ring as the primary enrichment device for blowthrough carbs is amazing to me. Basically an orifice plate roughly equivalent to the diameter of your main venturi. Under N/A and low boost situations, you get no enrichment. As flow increases, the vented pressurized air to the flow bowl increases at a marginally faster rate than that in the main venturi, causing the fuel level to rise and the main circuit to go rich, in porportion to the ammount of differenital. Very effective. You go 'rich overboost' which is the safe way to go. I guess 'TimSystems' wants to sell his controller more than providing full disclosure on the subject he's talking about. Such is life when you sell things for a living I guess: "My way is better, since I sell it!" Sad. If you think this setup is 'uncommon' in a Z, you just aren't looking in the right places, and are probably 24 years too late to see them all over like they were in the 80's in the JDM... Quote Link to comment Share on other sites More sharing options...
NATURALLYASPIRATED Posted January 19, 2010 Share Posted January 19, 2010 That plenum is beautiful, is it worth the money to ITB my l28 or just tweak my stock fuel injection? Quote Link to comment Share on other sites More sharing options...
NATURALLYASPIRATED Posted January 19, 2010 Share Posted January 19, 2010 I know I know, search haha Quote Link to comment Share on other sites More sharing options...
MazterDizazter Posted January 20, 2010 Author Share Posted January 20, 2010 I know I know, search haha Exactly. Options are nearly limitless Quote Link to comment Share on other sites More sharing options...
turboHLS30 Posted January 20, 2010 Share Posted January 20, 2010 I'm running triples w/ blowthru but I'm using cartech most people don't like the cartech stuff. Quote Link to comment Share on other sites More sharing options...
z-ya Posted January 20, 2010 Share Posted January 20, 2010 You can use a Megasquirt to do what the Tim Systems thing does. Except now you have a full 12x12 fuel map to program the fuel curve. While your at it, have it control the ignition too. This piggy back box stuff is all well and good, but I would either just do it with carbs (with some of Tony's suggestions), or just go all out EFI. A hybrid of the two is just a CF IMO. With all the effort need to install an EFI pump, surge tank, larger return line, etc. etc. to run EFI, you might as well just go all out EFI. Or stick with carbs. Quote Link to comment Share on other sites More sharing options...
Tony D Posted January 21, 2010 Share Posted January 21, 2010 "A hybrid of the two is just a CF IMO. With all the effort need to install an EFI pump, surge tank, larger return line, etc. etc. to run EFI, you might as well just go all out EFI. Or stick with carbs." Totally agree! Hell, strip out the venturis, turn the carbs into ITB's---that's the plan for my crate of 40PHH's out in the shed anyway. Screw some injector bungs from MSD in there, and run a 12X12 megasquirt. Carbs...er... 'blow'! Quote Link to comment Share on other sites More sharing options...
ArchetypeDatsun Posted January 28, 2010 Share Posted January 28, 2010 The first pic demenstrates it can be done with a 4 barrel carb and turbo set up the other two are a triple carb and turbo set up. Quote Link to comment Share on other sites More sharing options...
MazterDizazter Posted January 29, 2010 Author Share Posted January 29, 2010 The one with triples is actually in a 240SX for those who don't know. Quote Link to comment Share on other sites More sharing options...
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