Guest tdignj Posted June 30, 2004 Share Posted June 30, 2004 Ok....every time I upgrade my 240z it's great, but I need more power. I have a triple DCOE setup on my 240z 3 liter stroker motor. I have a ported e31 head with a good cam. The car runs strong but I want stronger. I don't think that there's anything else I can do unless I go to a fuel injection setup..but I like having carburators. I have a pic from the Z show in CA that I was given and told that this person is forcing air with some sort of turbo setup....does anyone know who this is and what they're doing? Any ideas or suggestions would be appreciated. Tom 71 240z Quote Link to comment Share on other sites More sharing options...
JMortensen Posted June 30, 2004 Share Posted June 30, 2004 Fuel injection is definitely the way to go. If you like the triple effect, maybe some triple TBs and a custom plenum. Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted June 30, 2004 Share Posted June 30, 2004 How much power are you making now? How much power do you want/need? If you do go turbo, FI is the only way to go. Quote Link to comment Share on other sites More sharing options...
Guest tdignj Posted June 30, 2004 Share Posted June 30, 2004 Hey Dan....we met at the Z show in NH last year. I have the blue 240z with the primer highlights....My setup is pretty much identical to yours. I don't know for sure how much power I'm putting out....I'll be going to the dyno very soon. I'd prefer to stay with the triple setup....but i'm open to suggestions. Tom Quote Link to comment Share on other sites More sharing options...
Sean73 Posted June 30, 2004 Share Posted June 30, 2004 As you know, jetting the Webers for a NA application is not trivial, nor is getting the parts. Double that effort for forced induction, and end up with something that runs maybe "almost as good" as EFI. You can probably get $800+ for your carbs on Ebay, which could pay for a brand new T3/T4, or be put towards programmable EFI. The triples do look and sound cool, but not ideal for turbo. If you want to get EFI on the cheap, I recommend the Z31 ECU, MAF and harness. It should be able to boost your 3.0 liter to 8-10 psi on the stock fuel injectors, without any special tuning. Also, the E31 head and cam won't be ideal for a turbo application. Sean 73 240ZT, L28ET, T3/T4, NPR IC, Z31 ECCS Quote Link to comment Share on other sites More sharing options...
z-ya Posted June 30, 2004 Share Posted June 30, 2004 There was a triple carb blow through turbo setup at this years convention. Beautiful installtion. He said he was getting something like 380HP at the wheels. He said it was a bear to tune, and it was a bit tempermental. What is your compression ratio now? Pete Quote Link to comment Share on other sites More sharing options...
Guest tdignj Posted June 30, 2004 Share Posted June 30, 2004 That's the guy I was referring to....my friend took a pic, but didn't talk to him. I'd love to hear what he has to say about doing that setup. I'm not positive about my compression ratio....should be somewhere around 11:1. Flat top pistons, shaved e31 head..... Quote Link to comment Share on other sites More sharing options...
z-ya Posted June 30, 2004 Share Posted June 30, 2004 Much too high for turbcharging. 8.5:1 max, and that's with fuel and ignition controlled by engine management. If you really want to do this, you would be better off starting with a junkyard turbo motor. CR would be around 7.4:1. Pete Quote Link to comment Share on other sites More sharing options...
Guest tdignj Posted June 30, 2004 Share Posted June 30, 2004 Thanks for the info Pete. If I was going to do something like that...I would have changed the head to lower compression to something around 8.5:1. Tom Quote Link to comment Share on other sites More sharing options...
Guest NapaBill Posted June 30, 2004 Share Posted June 30, 2004 Tom, Blow-through on Webers involves a lot more work than you would think, and won't give results that match F.I. Among other things, you have to supply pressurized air to the float bowl through the small breather hole between the velocity stacks. How you would keep those delicate brass floats from collapsing is challenge #1. Next, you have to come up with a way to seal the throttle shafts (the stock seals are for vacuum, not pressure) so that you are not venting fuel/air into the engine compartment and at the same time washing the lubricant out of the throttle shaft bearings. The anti-vibration mountings that help reduce sloshing and foaming in the float bowl aren't designed to seal against pressure, so you will probably have to solid mount the carbs, which brings the problems back. Sounds to me like its time to think small block! Good luck and have fun. Quote Link to comment Share on other sites More sharing options...
DAW Posted July 6, 2004 Share Posted July 6, 2004 CarTech offered a triple Weber (Solex, Delloroto, TWM-fit) plenum many years ago for the Zcar. I bought a new one from Corky Bell about 8 years ago and had to wait for them to drag out the old casting molds and cast a few. I sold it to a member here a couple of years ago, so there are a few of these out there to make the job easier. I wouldn't do a blow-through though, I'd use the triples strictly as throttle bodies (plug all unused carb ports) and mount injector bungs on the intake manifold, or use $TWM-type throttle body/injector assys in place of the Webers. It would be a unique setup but a lot of effort vs a conventional turbo/e.f.i. setup. DAW Quote Link to comment Share on other sites More sharing options...
technicalninja Posted July 7, 2004 Share Posted July 7, 2004 When I worked for Cartech in the early 80s one of the kits we sold was a blow through triple Mikuni set up which was very complete. It included all manifolds, turbo, carbs, intercooler, bypass valve, external waste gate, higher pressure fuel pump and boost sensitive regulator, down tube, air filter, all intake tubing, and a host of small parts. It was very expensive in 83/84 (approx 5000.00) but made 350-375 hp with excellent reliability. The Mikunis were the best carbs to use as they required the least amount of modification for a blow through application and required less 'tinkering" to keep in tune. The Mikunis worked pretty well up to about 15 psi and suffered fuel leakage issues above 15 psi. This system is pictured on page 103 of Corky's book "Maximum Boost". This book is a must-read for anyone considering modifying or designing a turbo system. The book is not car specific. It is theory specific and will answer most turbo questions while giving the reader a good basic understanding of turbo systems. Chapter 8 is devoted to carbs, both draw through and blow through, and adresses the special problems associated with them. Blow through triples can and have worked but it takes extreme attention to detail and proper engineering. F.I. is the way to go unless you have to have the "Triple Look". F.I. will be cheaper (maybe not at first but in the long run), have a greater adjustment range, require less maintenance, and produce more power IMO. The same aftermarket brain (laptop programmable) will probably support any engine you can put in the car (rotary, 4, 6 or 8-NA or blown). Although they look great the TWM peices will not make their value in EXTRA power and give the buyer back some of the problems of the triple carbs (more places for a boost/vac leak, syncronizing linkage, etc). The wonderfull triple sound is greatly reduced when a turbo is involved. I believe a stock intake plenum with a 60 mm T-body and minor port work can support 400 hp + and will prove very user friendly and be affordable. Your current engine might work with a P series head. If you are at 11-1 now the P90 should knock it down to 9.1-1. Mild chamber work should get you below 9. My suggestion would be as follows P90 head: mild chamber work, port matched to intake and exhaust, stock cam L28 intake: 60mm t body, mild porting at t-body and runner exits L28 ET: exhaust manifold, mild porting at runner entrances and turbo flange. Alternate injectors and fuel rail. Many types available High flow fuel pump and regulator. Stand alone EMS (engine management system-MegaSquirt to AEM- many different types and styles available. try to get one that controls spark timing also) T3T4 hybrid turbo (I like the T3 stage 3 with a T04E-50 compressor). Air to Air intercooler (700 cfm- less than 1 psi restriction). Minimum 2.25 inch intake tubes Good exhaust system (2.5 will work but 3 inch is better- all mandrel bends) Properly tuned this set up should make 360-385 hp on pump gas (93) at 14 psi and 425 plus on race gas at 18-20 psi. These figures assume the lower end is built properly and forged pistons are used. Cast pistons will actually work but I don't think they will last very long at 425 hp. I also don't thick cast pistons will last long in a 11-1 L-series N/A. Although I am a Nissan guy and like the L-series the Chevy small block/LT1 may be cheaper and provided same hp with less complexity. Changing to a V8 also allows you to sell the entire L-Series engine which should further reduce the cost of the Chevy. I believe the upper limit (within reason) of L-series power is 500hp and the Chevy is close to 1000 (both engines would be maximum effort turbocharged). this means your 425 hp Nissan is close to the limit and when failures occur they will tend to be catastrophic where a 425 hp Chevy is much less high strung and may be more dependable. Further mods to the Nissan will be far pricier than further mods to the Chevy. The V8 conversion helps the resale value of the entire car better than the blown 6 cylinder IMO. Well There's my ramblings on this subject Hope it helped Rick Quote Link to comment Share on other sites More sharing options...
DAW Posted July 8, 2004 Share Posted July 8, 2004 Very well done, Rick. Makes a lot of sense, but I have a tough time rekindling some sort of relationship with pushrods. 5.7 liters should be accountable for a lot of horsepower since it's twice the displacement of the L6's. I've built a lot of really fine Chevy engines and had a lot of fun with them but there's some aesthetic re powerplants wherein garden variety Chevys (Fords, Pontiacs, Mopars, etc., etc.) don't make the grade. GN V6 turbos are far more progressive, in spite of the pushrods, but SOHC/DOHC engines have a simplicity/horsepower ratio that is far more satisfying. Wankels make a lot of power for their weight and deserve a look...the c.i./hp ratio as compared to a Chevy engine, stock or modified, makes the Chevy look antiquatede, anemic, and pathetic. I can't believe I'm actually writing this...I just drove from the Florida Keys to Seattle with what seems to be a herniated thoracic disk and a numb arm...must be the pain meds talking and I disclaim this text...DAW Quote Link to comment Share on other sites More sharing options...
DAW Posted July 8, 2004 Share Posted July 8, 2004 Rick, so obviously I have some mental block, but the fun-factor has an undeniable appeal in this formula. I have some surplus Z-cars, and I suppose if the right conversion kit and sbc came along at the right price, I'd have to go for it. At some level, it doesn't matter what makes your head snap backwards. DAW Quote Link to comment Share on other sites More sharing options...
Tony D Posted July 11, 2004 Share Posted July 11, 2004 webers will work, but get composite float assemblies from later models, as mentioned earlier, the brass units tend to collapse around 10+ psi. The guy you are talking about is David Glidewell, and is a Group Z member. You may be able to leave a message at the Group Z SCC Yahoo Groups Site and maybe he'll contact you with some answers. David and I were the two of the three or four "blow through turbo"guys in Group Z back in the early 90's. My tank was a copy of the HKS Surge tank, and didn't sufferethe lean surge problems inhjerent in the smaller cartech styled box. Something to be said for pressure diffusion and proper airflow entry to the carbs. I used soft mounts on my carbs, and never had blowout problems, then again I was using good Mikuini Pieces, and not the phenolic knock-off crap sold today. Mine was low-key, running only 10 to 17psi (when I got spunky) and returned 17mpg in daily driving to and from work in SoCal. It also gave me cleser to 5mpg when driven hard. Everything encountered with carbs is solvable if you have the right information. David is unwilling to experiment with modulator rings in front of the carbs to take care of his lean surge transition problem, as are most people when they reach that stage of tune with triples and a blowthrough setup. I, myself saw the light, and went EFI some time ago. It has taken some time to find the original HKS EFI TB's (triples like the Mikuinis) and the original HKS Surge Tank (was over $1000 in Japan whilst I was there) so soon an "old school lookalike" turbo motor will be back under the hood of my 73... And Sharkie will prowl once again! Really, go with EFI and save yhourself a LOT of headaches and an excruciating learing curve! There is a lot to be said for going out to the car, and just turning the key after a hot run and shutdown on a summer day. Believe me, if you think 74 and 73 engines had hot-start issues, try driving a blowthrough turbo car in desert heat! Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 11, 2004 Share Posted July 11, 2004 My tank was a copy of the HKS Surge tank' date=' and didn't sufferethe lean surge problems inhjerent in the smaller cartech styled box. Something to be said for pressure diffusion and proper airflow entry to the carbs. I used soft mounts on my carbs, and never had blowout problems, then again I was using good Mikuini Pieces, and not the phenolic knock-off crap sold today.[/quote'] ...You mean that problem where no matter how you tune it, no matter how you setup the accelerator pumps and jets, the engine would just fall flat on it's face unless you eased into the throttle? I was starting to think it was just me... I had the Cartech triple Mikuni setup back in the 80's, and it was the best thing available in the states at the time (fresh out of college in the Midwest with no internet - I had no knowlege of any JDM stuff even existing ), but I'll be damned if I could get the thing to not stumble badly on a 5-3 downshift... After I switched over to EFI, this problem went away immediately and never returned. Quote Link to comment Share on other sites More sharing options...
Synlubes Posted July 11, 2004 Share Posted July 11, 2004 I`d like to go with a nice EFI setup, but I`m old and just love my triple Webers. They are kinda like a "high maintenance woman", but once you understand them there not as much of a mystery (although they can still be a pain in the a$$). And did I mention the Sweet Sweet sound they make sucking in all that air. Quote Link to comment Share on other sites More sharing options...
lwrnclightner Posted March 12, 2014 Share Posted March 12, 2014 I know this is an antiquated thread and topic, buuut... I am new to the turbo them. A little background so that I'm not eaten alive. For months I have been saving and planning to have a stroker built. Last night talking in depth with my engine guru buddy who will be doing all the work, he convinced me that stroker has some concernable drawbacks for how the car will be driven, almost daily street purposes. He informed me of all of the benefits of turbo and that with some tinkering that my trip mik's are doable but webers may be preferred for a blow thru scenario. Now that I am starting to research blow thru turbo I see that this is old news and I would be one of very few that would still be running that set up. But I love the carb look, sound etc etc etc, So I think with his expertise it can be pulled off. I'd like to start researching my best options in todays tech. I would think it should be a little easier than when this thread last ended. I see Tony D has EXTENSIVE first hand knowledge and he made it work. Tony D can you and all the other pros help this fledgling get started? So with what I have already... F54 block, n47 head and trip MIkuni's, how much would I expect to need to get me in the turbo game? I hear that turbo can be had for less than the stroker so ball park what am I looking at $$$ wise and what kits are available to get me started. To have it done right and last, I know it won't be cheap and I will spend what needs to be spent without cutting corners to get it done and stand up to a little abuse now and then. My engine guy knows exactly what he needs to get it done, but of course I couldn't comprehend being the first conversation over the phone talking turbo stuff, and I am the type that wants to know how it all works and why, so while I'm waiting for him to get to my project I thought I'd start to educate myself. Thanks in advance guys, Lawrence Quote Link to comment Share on other sites More sharing options...
madkaw Posted March 12, 2014 Share Posted March 12, 2014 From what I have researched you need a box for pressurizing. Not just a 2x4- something to disperse the air evenly thru all cylinders . Ignition control- spend the money on mega jolt or something to make effective ignition curves and save your engine. Better yet, get a MS 2 unit to control everything but fuel, boost, fans, ignition, run a MAP sensor, data logger. Be prepared for a LOT of work and not a lot of support Quote Link to comment Share on other sites More sharing options...
gorillaman2012 Posted March 14, 2014 Share Posted March 14, 2014 If I were you..go to theturboforums.com it's literally all about turbo charging whether it's with carbs or not. Crazy amount of info there. Quote Link to comment Share on other sites More sharing options...
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