JMortensen Posted January 6, 2007 Share Posted January 6, 2007 Cary and Paul, I've had the same argument with a more than one person who claimed the triple SU wouldn't work also. They always wanted to argue about the firing order as well, but none of them could explain how a triple Weber/Mikuni/ etc set up could work so well and not a triple SU set up. If their theory was correct, then wouldn't it stand to reason that the center carb of a triple Mik/Solex/Weber would have to be jetted substantially different than the other two? Of course, when I would bring that point up, they always backed down a notch. I always contended that with a balance tube (which Steve has) it negates a lot of their theoretical problems with the SU set up. I talked to Bruce at ZT and he sent me a couple pics of Steve's work just before he finished it and I have to say I love the fact he made it look like it was an OEM piece. I have a triple SU handmade manifold that I plan to experiment with also whenever the money for some modifications is in my hands, there is no crossover or balance tube so until I get that fabbed up and welded in, it's going to sit in a box on the shelf. I think the theory that there is an issue with the firing order and that the center carb won't get even intake pulses is CORRECT. The thing is, that DOESN'T necessarily mean that the car isn't going to run well, and that's where the naysayers cross the line. It just means that it won't run AS well an engine with a nice even firing order. How many Jags went into production with triple SU's on an inline six? To say it "isn't going to work" is just foolish. This bit about the triples is wrong though. The triples have a separate barrel for each cylinder. Each cylinder is getting it's own intake compresion power and exhaust strokes so the center two cylinders share a carb body and a float bowl, but that's it. Quote Link to comment Share on other sites More sharing options...
nismoztune Posted January 6, 2007 Share Posted January 6, 2007 Sorry for the way off topic, but I couldn't resist... I don't think he'll mind, so here's some triple-SU candy for you, built by Steve Epperly (ZTherapy)... . . In my opinion, there are many welding projects that you could perform on your Z... the Weber's are a large waste of your time. nice set up SU . Ron ( Ztherapy) Quote Link to comment Share on other sites More sharing options...
WEBEZEEed Posted January 6, 2007 Share Posted January 6, 2007 Weather it works or not I don't care..... that's just plain old neato,keeno,coolo!! Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted January 6, 2007 Author Share Posted January 6, 2007 Weather it works or not I don't care..... that's just plain old neato,keeno,coolo!! well said Quote Link to comment Share on other sites More sharing options...
TimZ Posted January 7, 2007 Share Posted January 7, 2007 I think the theory that there is an issue with the firing order and that the center carb won't get even intake pulses is CORRECT. The thing is, that DOESN'T necessarily mean that the car isn't going to run well, and that's where the naysayers cross the line. It just means that it won't run AS well an engine with a nice even firing order. How many Jags went into production with triple SU's on an inline six? To say it "isn't going to work" is just foolish. This bit about the triples is wrong though. The triples have a separate barrel for each cylinder. Each cylinder is getting it's own intake compresion power and exhaust strokes so the center two cylinders share a carb body and a float bowl, but that's it. Thanks, Jon - you saved me from having to type all that. For the record, I never said anything to the effect that it wouldn't work. The firing order is just an issue with that design that makes it less than the ideal setup. Unless you change the firing order of the engine, the center carb is the only one that is going to see evenly spaced intake pulses, and that's just how it is. The point of this is that because the 1 and 3 carbs see event spacing that looks pretty similar to that of the two carb setup, you should be able to get a two carb setup to run pretty much the same with proper tuning. Perhaps the even event spacing of the middle carb with fewer events per rev helps more than the uneven spacing on the other two hurts, though. Does that mean it won't work? Nope. How much less than ideal is it? Apparently not that much. Do I really care that much? Nope. I was just pointing out a subtlety in the design. Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted January 7, 2007 Author Share Posted January 7, 2007 Does anyone have the intake flange dimenstions? Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted January 7, 2007 Administrators Share Posted January 7, 2007 Does anyone have the intake flange dimenstions? I am currently building an EFI manifold... I have included the head flange dimensions here... http://forums.hybridz.org/showthread.php?t=117607 A couple things to keep in mind... Carb'd heads have their upper mount bolts in a different location than EFI heads. Also, I have shifted the ports up slightly for improved entry. Using those dimensions with .125" wall tubing will put the floor of the runner at the same 'elevation' as the floor of the port. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted January 7, 2007 Share Posted January 7, 2007 The ironic thing here is that I thought of the exact same thing (3 SU's on a custom manifold) a few years ago, before I found this web site and before I even knew much about the SU's to beguin with! I just looked at the 240 SUs on their manifold and thought.. 'hey, why not 3?!?' I had all kinds of people tell me it wouldn't work, and it would be impossible to tune.. but having delt with some webers since then, and having next to NO problems with my SU's, I think I might try this now.. I have a spare set of SUs anyway, (so 4 in total) and I do know how to weld now.. Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted January 7, 2007 Author Share Posted January 7, 2007 Ron, you are a lifesaver. I have access to a computer controlled plasma cutter. I think i will try to make a CAD file for it and cut it 1st chance i get. What thickness should the flange be? Quote Link to comment Share on other sites More sharing options...
Administrators RTz Posted January 7, 2007 Administrators Share Posted January 7, 2007 I think i will try to make a CAD file for it and cut it 1st chance i get. I can email you a .dxf file if that will help. What thickness should the flange be? I choose to use 1" largely to allow room for the injectors to be machined (into the 45deg. back cut). With carb's you could use thinner material. I wouldn't use anything less than 1/2", but I'd probably recommend 5/8" if you're going to use aluminum. Quote Link to comment Share on other sites More sharing options...
gjc5500 Posted January 8, 2007 Author Share Posted January 8, 2007 The file would help alot. my email is Gjc5500@gmail.com im going weld steel so would 1/2" be fine? Quote Link to comment Share on other sites More sharing options...
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