brokebolt

I've been thinking all day about this. We Z guys should pressure not each other for facts but others with the resources to get things done. We should have an independent organization do a "Induction Challenge" and post the result for all to see. It would have to be someone impartial and knowledgable about Z cars and the different inducitons. We would need to use the same car and have a team organize it all. I'm no promotor just a Z guy looking for fact, what ever the facts are. Get "Sport Z" magizine to set up camp in Arizona (or someother location) and do some dyno pulls using a stock L-28 and the different inducitons. Sport Z can post the results over several issues keeping the sales up and getting the information out that we Z guys would like to see. It is Sport Z after all and we are discussing Z sport cars. I could see that many parties would like to see this, AZCar, Ztherapy, Sport Z, Clifford Research, Weber, Cannon, and TWM. All of who have a stake in the market for aftermarket Z enthusiests. Dave, I see what your specific addressing about throttle response. I would not agree that the 4bbl is the only induciton with good pep on the throttle. Any hesitation, backfire, or other induciton related problem would need to be sorted out and would suggest a problem. The 4bbl may give the driver the perception of more power due to the different power bands of the induction, but the Dyno would varify beyond arguement. I'm not pro SU or 4bbl or trippple or even EFI but lets see some raw data on all of them, that is my only point. I agree tuning trippples for ANY purpose is a ball of wax. Cost goes up (everthing is in sixes, jets, etubes, etc.) and so does the skill level. Much more involved than a single downdraft or dual SU's. Let's get Sport Z involved. Mike

Dave, Unfortunately I have no plans to visit the Arizona area anytime soon, I just got back from Lake Havisu, nice body of water, liked the pasties on the girl in Havisu City. Would you be inclined to some other options? I have the other two set ups as stated but the Bob Sharp manifold I sold months ago (wish I had that back now!). Also are we discussing a stock L-24, L-26, or L-28, or a modified engine. If you want to go stock that I would have to assemble a stocker and that wouldn't be available until the end of summer or early winter. I'm not making a challange I'm just curious as to what the different inducitons actually look like on a Dyno. It would be best to use one car and only change the induction, I think everyone can agree to that. I can't recall anyone who has done this type of testing and if so would be nice if they would share the numbers with the rest of us. A few questions Dave, you say "better throttle response and drivability", what are you angleing at here? I'll address the other points as you stated cleanliness, I say personal perception, trippples are the cleanest. But the 4bbl doesn't take up that much space it is very compact. Ease of maintanence, yes parts are more readibly available at autoparts stores and such; ask your local parts guy for SU needles and nozzles or even needle valves. Gas milage, I can't comment on that but anything driven concervitily can be a fuel saver, also foot to floor=bad MPG numbers. I think we are comparing apples to oranges here but the real issue would be performance. And performance is what most folks are interested in anyway...Dyno tyme. Mike

I've got a Clifford research manifold and a stock set of 1970 bell top SU's, I used to have a Bob Sharp manifold but I sold it (what was I thinking). I'd be inclined to test my set ups on a Dyno for results BUT I have two 4bbls that are not 390 CFM Holley and only one is in good runable conditon. Junk yard carb as it were. If someone has a Bob Sharp manifold and 390 Holley out of the box it would make for a good comparison. Three inducitons, three dyno runs, all here in Sacramento Ca. 75 feet above sea level. That should set the record strieght. First I got to get my old heap off the jack stands. We could even toss in some Dellorto vs. Weber vs. Mikuni comparisons on a TWM vs. Cannon vs. Mikuni manifolds. Mike

Hey mulletz, Here is another link to a recent descussion on the SU's issue. This is SU's vs. Trippple but the discussion is quality never the less. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=33732 Mike.

Norm may be running 12's but have you seen his pics of the tranny? I have, that guy is hard on parts. Not bashing, but I'd like to drive my car home from the drag strip. I guess you gotta break a few eggs to make an omlette. Would be nice to see some dyno numbers same day of 4bbl and SU's on same engine. Dyno's don't lye. Mike:D

Dave, I've bought stuff from you in the past, one question, does this spacer have the port on the top for the air tap thingy that is on the stock TB unit? Mike

Dave makes some valid point. I am not a master mechanic but do have some years of experience in Z car related inducitons (one or two). I like the SU as it is original equipment; nice to keep it in the family so to speak. I like the 4 bbl good performer, but I like the Trippple set up best. But leave the third out as this topic is about the first two. SU's lack top end, I had issuses feeding my engine with enough air and fuel above 5000 RPM's to keep the engine happy. I have pics of two exhaust valves to back this claim up. I don't have the head gasket anymore and I didn't take pics of it but it too was no longer usable. Go here to view the valves. http://www.cardomain.com/memberpage/496289/2 The SU's are a great daily driver carb and are easy to tune. Performance, fuel ecomony, and reliability are all in the pro column for SU. For "stock" carbs on 1970-72, performancs is good, my fuel economy was in the neighborhood of 20 mpg (driven conservitely) and once tuned (nut on bottom and balanced front to rear and other misc. points of tuning) they were a good reliable daily driver carb. Con is performance above 5000, parts, wear, age, and special tools. Parts are still available though "aftermarket sources" (I used to get parts from Nissan years ago, don't know if they are still available now). Wear is not an issue with Ztherapy SU's (I don't own any so this is what I've read from customers) and age is always going to be a factor with 30 year old hard parts. If your home tuning you need a flow guage to balance the carbs or they will not run correctly. The 4bbl in my experience was never a fuel saver (foot to floor issues), I have no read MPG number, I never used them for daily driver use. They required more carb knowledge (if you tinkered with with jet sizes and such) and installation was not as "bolt-on" as the SU's (you have to fab linkage or a cable set up to some degree and figure out what goes where, Dave covered most of these issues in his post). They are reliable but carb choice is an issue and people tend to thing "big=good!" And junk yard parts are just that, junk yard parts. You may find a mint diamond or you may find a worn out peace of junk that needs complete teardown and cleaning just to see what shape the part is actually in (been there!). However, they use new parts (if bought new) and parts are available at every autopart store from San Diego to Boston. Everyone, including there brother, knows something about downdrafts so you have a good change that you know someone that actually knows something about tuning. I think the comment about Mixture distribution is not correct. The real issue is in the length of runners. The Bob Sharp manifold (AZCar is the same) and the Clifford Research manifold have solved this. The Bob Sharp manifold feeds like a dual plane Log style while the CR manifold feeds like a Plenum. The difference is the Bob Sharp manifold will give good low end power while a Plenum will give better top end, these are how the characteristis of the design work in general. I think the issue of mixture distribution first stated years ago when someone made the comment about the SU manifold and how it has different length runners. And yes Nissan did a good job of not using a Plenum or Log style to make a compact dual set up to feed 6 holes. Nissan compared to European cars have been using the SU style carb for years with great success on 4 banger sports cars. But the Nissan version has different lengths in all 3 runners, front and back carb respectily, while a four hole will not have this use (Nissan should have used three carbs to eliminate this issue altogether). So anywy, the 2nd and 5th cyl. have shorter runners, one and six feed off of two and five and three and four have dedicated runners. This will affect the engine, to such a degree I don't think you could detect it unless you used sensitve diagnostic equipement. The bigger issue I think is the pulse you generate from the SU (and Tripples) vs. the 4bbl with a constant draw. Bottom line if I was to recommend to anyone an induction, I'd tell that person to open there wallet and let the dead presidents decide. Ztherapy may have a good product but at what cost? The 4bbl may be an economical investment for all new hardware but there not original equipement. If the choice was mine, and I'm old school so no computers under the hood for me, I'd use a Trippple carb set up. Even though EFI is "The Wave of The Future" and more performance can be gained easier. I feel nothing looks meaner than three carbs with individual runners. I say the "all original" guys can view my tail pipe, and the Holley crowd can hang out with there V-8 buddies. But that's just me. Mike

Here is a link to a discussion on this very topic. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=23727&highlight= Mike

Yes, bubbles in the return line going into the bucket would suggest air in the fuel lines. Do the same bucket test but only run the pump leave the car engine off. This will make a conditon where no fuel is removed from the lines. If you duplicate the same results than I would think there is residual air in the fuel lines. The pump is prossibly cavitating and thus drop in fuel pressure and bubbles in the return line. The Holley Blue pump is a rotoray vien pump and requires fuel to seal the viens to provide fuel flow and pressure. This is also a good test to see just how well your needles and seats are sealing. If the fuel floods the bowls than the needle and seats are worn and/or the pressure is excessive (you did say nice low pressure @ 3.5). This test is good to check the fuel bowl level aswell. Mike

National Dragster, May7, 2004, issue number 15 in the "Racing Technology" section pages 85-87, "Manifold Destiny-Part 2" written by Evan J. Smith; has a further discussion on manifold design. Nothing I haven't seen in books and from listening to old folks chat but it is a good breif summery. If nothing more it should get people asking questions next time they go into their local speed shop. I think it's an attribute for such publications to discuss issues like this as it is one of the most mis-understood parts of the engine. Happy trails. Mike

Here is my take on it. The cylinder head looks in good condition but without a real examination can't make a statement to that. Ask for pics of the intake and exhaust ports. If he is willing to get them to you he would be an excellent ebayer. Looking in the pics the spark plug holes don''t look anywhere near new. They appear to have some engine gunk on the outside of the holes. I'm sure the engine has been gone through at some point but a good look at the valves, combustion chamber and exhaust ports will get you undisputable evidence. I had an old grubby head cleaned by my local machinest that was fully assembled, the thing looked like brand new when I got it back. Every part on it was shiney and cleaned, even the back of the valves. The only way you could tell it was used was the wip pattern on the cam and the cam followers, and the valve seats and contact area on the vavles. Mike

I think we totally agreee, Trippples are best at high RPM's, SU's are best for a daily (the best MPG I ever got was 21 or so with the SU's, the worst was 8 or so). I like the comment about scaring children, but you forgot the small animals scurrying to their haven. On a side not, I raced a 1/4 mile in my old heap wih SU's, the guy on the other side, 260 Z with Rebello tuned Trippple Weber DCOE 40's. I did win (yah me) but not by much. On another day, a 90ish Camero with a 350 was yet another barely win situation. Oh, but the best story of all was a 427 Chevelle. I was way quicker out of the hole with my SU's, but when the C.I.D. of that big block kicked in at about 3500...well we would rather forget that. But I do remember the California liceinse plate "66LICKS". Mike

It's been stated before, cost vs. performance. And you don't get something without giving up something. Slow corner; SU vs. Trippple, you can set up a Trippple to preform there; but you loose somewhere else. You have to tune the conditons through sacrifice and gains. No carb is "best in all conditions", only EFI can give better than carb performance. Ever seen a Hilborn guy tune, I'll take my Trippples or even my Bell top SU's over that ball of wax. But I'll bet my money on the Hilborn guy in the 1/4 mile. Mike

If your not making enough HP on the low end than your not set up correctly, with either induciton. Trippples can produce more power on the low end and pull hard thought the RPM's if set up correctly. The real difference you will see with Tripples over SU's is the Trippple set up will be more tuneable. I ran Bell top SU's for years on a 3.1L engine, good response but no top end performance at all. I couldn't get enough fuel to flow through the needle, nozzle combination. Yes, the Dashpot with heavy oil (30 Wt.) did give the needed accelerator pump fuel action but on the top end it ran lean, even with custom machined needles and nozzles; note the carb bodies were unmodified. With the Trippple 40 set up, I had much better low end and even better top end performance. Story: With the SU's from a rolling idle if I punched it, the tires might squeal a little bit, and pull hard to about 5000 RPM's but then I could tell a tappered off effect to 6000 and some real effort to reach 7000 RPM's. With the Dellorto 40's I ran, same idle roll it would light up the rear and I had to feather the throttle a bit to get them hooked back up and than the old heap pulled hard thought 7000. The MSD shift light is set at 7000 and I was well into the light before shifting from first to second. Moral: If your Trippples are not tuned correctly than you will never see the performance and your induction will run like a tired old mule.You should see a perfromance advantage with Trippples over SU's thoughtout the RPM's, if you don't your not tuning them correctly. Conclusion: I like the SU's great drivers carb but not as much performance potential as a well tuned set of Trippples. And I concure that if not set up correctly the Trippple set up isn't worth it's cost. Trippple carbs; six main jets, six emultion tubes, six idle jets, six air correction jets, six idle jet holders, six pump jets, six chokes and six auxiliary ventures. Twin SU's; only two nozzles and two needles. Mike

I'll toss in my $0.02. If your looking for an easy to tune carb SU's are the ticket, if your looking for potential power use a Trippple set up. That's it in a nutshell. But you did mention some mods down the road, if your interested in a one time investment, than maybe you might want to look closer at the Trippple set up. Yes as mentioned the SU can be bored out to run with the big dogs but a choked up Trippple can be tuned for smaller displacement engines and than when the mods are done opened up for bigger and better engine mods, like cams headers and such. Personally if your looking at perfomance I'd recommend a performance oriented carb like the Tripple carb set up. Yes SU's can be modified to preform but the Trippple carb has those mods built into their design so no modification is needed, you only need tuning parts to do so. I believe that the Trippple set up is more tunable than the SU's but that statement may spark a debate. What I mean by "more tunabiltiy" is that the Tripple set up has more specific controll over a paticular RPM range though the use of the tuning parts. SU's have controll over the dashpot only which in-turn controlls the other parameters of the carb. Mike

Coleman propane torch tank!!! Thanks, it's been buggin' me for a while now. I knew I'd seen it before. Thanks for the post Mike, no more long night tossing and turning for me. Hey Mike Kelly, thanks for the kind works. Nice to see a Zguy that knows his stuff. Mike

In the April 23, 2004, issue number 13 of National Dragster, on page 74-76 written by Evan J. Smith is an excellent article in the "Racing Technology" section titled "Manifold Destiny-Part 1" it is about manifolds. He discusses many things, one thing I like is his discussion on resonance. This topic could be more in-depth but the point he makes is very important and valid for anyone running a "Cannon" manifold. I know this topic has been over done but I now have current independent sources that I can site to aid in the argument over the Cannon manifold issue. On the "long runner" manifolds, it is better suited for low end power. I believe most people think their tach reads 7000 RPM's redline they should buy a manifold that has best flow characteristics at that RPM. I beleive most poeple want "out of the hole power" not top-end performance. The Cannon manifold "can" help with this low end power issue. Also twin exhaust pipes help, run them all the way to the back of the car and Y-em' just before they exit the pipes. I have been preiching for years that if your a daily driver Z guy, the Cannon manifold is a good choice. Redline also makes a "Cannon" style manifold with almost the exact same dimensions. I personnaly run a TWM, for cleanance issues. I see postings all the time how "Cannon is junk":roll:, I can feel my jaw tense up everytime I read tha stuff. Happy trails! Mike

I was just emulsed in a e-mail session with a guy about this very topic. Here is my $0.02. Fuel return lines are nice becuase they keep a fresh fuel supply at the carb inlets. Yes most fuel pumps are a rotary vien pump design and yes fuel is used to lubricate the viens as they operate. If you dead head the pump than the fuel must release pressure by by-passing the vien. This "can" cause wear and "lead" to premature pump failure. Also if you use a oil cooler and run the fuel through it before the carbs this can cool the fuel before it is feed to the carbs and the unused cooler fuel can return to the tank, helping to keep the tank cooler. While I've mentioned it, Z's are the worst design for gas tank temps, all the engine heat and exhaust pipe heat hits the fuel tank dead on. I like a cool can before the carbs to help combat this, but who drives around with a ice chest full of ice and a aluminium coil running though it anyway. Mike

Mark, thanks for the response and the offer. I will definety think about it. Steve, thanks for the response and the offer. Say...you living so close to me would be nice to take a peak at what your done there. Looks nice, is it road worthy yet? I'm still in the research phase of this project, still trying to get some input on handling issues and perfromance. Do you have anything to report on those topics? I'm curious as to anyone that is running camber/caster plates and really big meats. I'd think that top mounts would be the way to go with lower adjustable links. That would mean custom jobs on the transverse links and such. Anyone seen any locations for that type of stuff or better yet used any? I know AZcar provides the top to bottom stuff on the coilover area and links. Mike

What are you looking to get out of them? They are much smaller than I had hoped for but I'm willing to entertain offers. I've got a few leads from HybridZ members that I'll check out. And thanks for the tips guys. I'm considering the monster flares, I've done custom body work in the past, I used to work in a body shop when I was in college. It can get real "fun" working custom stuff sometimes. Especially when you make a mistake. Doh!! Mike

Ron, Ya Dandos, that's the name. Thanks for the tip on Les I'll give him a buzz on the telly. Mike

Did a search but the new format is a bit odd for me, I'm used to the old one, anyhow. Anyone know where to get real big pre-fabed fender flares? I was considering 10" fronts and 15" rears. I know "Dandito's" in the bay area had them a few years back. I was thinking about creating the "Bob Sharp" look only in solid Black. Also considering making adjustable rear transverse links and front suspension geometry similiar to what "A-Z-Car" is selling. Any input would be nice to fuel this discussion. Any one done this set up? Any Pro's con's on handleing and performance? Mike.

Do a search using author on this forum and my log in. You should find 9 postings some will contain info on junk yard parts that you can get that will bolt on to your Z. Go here for a quick look. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=19020&highlight= I've been passing around sections of my notes page for a few years now. Use the info that I have posted as you like. Here is a link to the page that has all the same info as above with out the discussion on page 6. http://www.cardomain.com/memberpage/496289 Mike

Go here, http://www.racetep.com/ztripdcoe.html I seen this pic and was inclinded to make my own. TWM does sell one and for what your getting it isn't a bad price. With parts and labor your would be lucky to get one made that cheap. Mike

Most you've gotten!?!?! Sounds to me like the trippple guys aren't being very information friendly (not a slam guys). I'll get some pics on my album this afternoon or tonight to show what my install looks like. I've seen your set up, wow looks like spaghetti under the hood. Also I forgot, I removed the smog pump and related items. My headers have the injection ports for the smog pump but I removed the injector tubes and put a plug in the holes. A lot of smog equipment should be on the balance tube of the original manifold. The EGR on the balance tube was removed and my headers have no port for the pick up, well I did put one in to make the smog man happy. I'm running a 1975-78 vaccum/mechanical advance distributer, with a MSD 6AL ignition. Long story short on smog, my car ran better number with no smog stuff than with everything that a 1973 car should have on it. Go figure . Mike Here is my page in progress: http://www.cardomain.com/memberpage/496289