2fast2Z Posted February 24, 2010 Share Posted February 24, 2010 This might be the stupid question of the day, but i like to know if it will be a good idea to have a balance tube on the triple manifold or not, i have searched but not fount anything useful. Chris Quote Link to comment Share on other sites More sharing options...
brokebolt Posted February 24, 2010 Share Posted February 24, 2010 (edited) This might be the stupid question of the day, but i like to know if it will be a good idea to have a balance tube on the triple manifold or not, i have searched but not fount anything useful. Chris Some Cannon manifold have the balance tube bored clean through, others were bored only on the ends between the the fifth and sixth holes; some also had it on the front one and two holes. Others I seen have not been bored at all between any cylinders. Mikuni used a plate that sandwiched between the carb and the manifold and had a cut out between the bores on the same carb, unsure what they came from. FET made a manifold that has a balance bar on all six runners with several taps on the bar. The Mikuni manifold has bungs on each runner so you can add a small block manifold with tubes. The benefit would only be at idle and low speed operation. At W.O.T., or close to it, you're drawing way more air though the bore of the carb then you ever could through the balance tube. Yes, the benefit would be a smoother idle and low speed operation but that really would depends on the engine set up, cam, etc. If it idles rough with no balance tube it's gonna idle rough with one... just not as bad. If your looking for a smooth idle then a triple set up isn't the key, the carb is "on" for one pulse and then "off" for five. The SU's have an alternating pattern of "on", "off" that with the balance tube have a very smooth operation and idle due in part to, what I would consider, a huge internal volume of the stock balance tube. And it makes a great place to stuff a bunch of smog junk... Edited February 24, 2010 by brokebolt Quote Link to comment Share on other sites More sharing options...
2fast2Z Posted February 24, 2010 Author Share Posted February 24, 2010 (edited) And it makes a great place to stuff a bunch of smog junk... LOL No smog stuff on my SU's Thanks alot for your explanation, the car is for street only, so i guess i can take advantage of a balance tube, the thing is that my manifold (Lynx witch i have found out is not the best)have a crappy linkage, i'm welding on 3/4 inch aluminimum towers, being that the present linkage is attached to a row of bungs and it is located 2 inch to low and 1 1/4 inch to close to the head, now after relocating the linkage, i will have those bungs avalible and got the idea of connecting the runners with a hollow aluminimum bar, mounted with banjo bolts to each runner, then on that bar i could drill and tap for brake booster and even crank vent, but before going in to all this efford, i needed to know, if it would be worth it. Chris Edited February 24, 2010 by 2fast2Z Quote Link to comment Share on other sites More sharing options...
brokebolt Posted February 25, 2010 Share Posted February 25, 2010 (edited) LOL No smog stuff on my SU's Thanks alot for your explanation, the car is for street only, so i guess i can take advantage of a balance tube, the thing is that my manifold (Lynx witch i have found out is not the best)have a crappy linkage, i'm welding on 3/4 inch aluminimum towers, being that the present linkage is attached to a row of bungs and it is located 2 inch to low and 1 1/4 inch to close to the head, now after relocating the linkage, i will have those bungs avalible and got the idea of connecting the runners with a hollow aluminimum bar, mounted with banjo bolts to each runner, then on that bar i could drill and tap for brake booster and even crank vent, but before going in to all this efford, i needed to know, if it would be worth it. Chris Honestly, unless your doing all the welding yourself, the cost might outweigh any benefit you would gain, in my humble opinion. As far as addressing your engine vacuum issues, an aftermarket vacuum system would be the best solution to evacuate the crank case of spent blow by gases and such. That would also be the most expensive option aswell. As far as making a vacuum log (as those EFI guys like to call them) then you can make one relatively easy as long as you tap each runner and pull vacuum from each runner to ensure no lean cylinders. That could get messy real quick if you were burning up parts. As far as welding up a manifold, you sure could do that but I wouldn't expect to see any real improvements except at maybe idle. The firing order may not lead prudent to having enough time to smooth out the idle across all the cylinders. It wouldn't hurt anything, maybe performance but other then that, as long as the welds were good and no leaks... give it a rip and try it out. Haven't seen anyone do this... yet. I might consider welding bungs on the remaining runners and simply running a vacuum log with hose fitting from each runner. If it doesn't work out like you expect you can always plug the bung holes and your only out the cost of adding the additional bungs. Or maybe spray some "juice" in those runners and scrap the vacuum log idea altogether. Your call. Edited February 25, 2010 by brokebolt Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 26, 2010 Share Posted February 26, 2010 If you add a balance tube, make it REMOVABLE. You CAN NOT synch the carbs with one on there! What I noted on my turbo car was that without the balance tube, I could literally feel every cylinder hit---a bery 'bumpy' acceleration. Once I installed the balance tube (constructed out of brass T's and 1/4 and 3/8" fuel line) the acceleration was turbine-smooth. Made a REAL difference in the way the car felt on boost on throttle. In N/A mode, it seemed slightly smoother as well. WOT or not. It definately helped with the idle. While the statement that the carb in triples is "on" for one pulse, and "off" for five---the balance tube changes that, and you can literally run the car off any one of the barrels. It makes a big difference at the lowest engine speeds where every cylinder sucking slightly from an offline runner keeps air moving through the carb barrel helping transient response when the throttle is opened. As best as I can explain it now... Quote Link to comment Share on other sites More sharing options...
2fast2Z Posted February 26, 2010 Author Share Posted February 26, 2010 You two, thanks for your reply. Mr. Bolt i know the right persons to have this done for the right kind of money (a little to none) and i want to make a heavier linkage using 10 millimeter rose joints just to make it more solid than the 8 m.m. i have now. Tony, you explained it well, my plan is to use 3 piece of 3/4x3/4 inch aluminium, have them drilled out and tapped in the ends, then connect them with brass fittings and plug the outer ends, i will then drill and tap the bungs (there is one at each runner) and then attach those aluminium bars with banjo fittings, in that way i can remove and plug when i have to sync. Does that sound as a plan or a waste of time, i do like the idea of better low end. Chris And just a teaser, my future plan. Quote Link to comment Share on other sites More sharing options...
brokebolt Posted February 26, 2010 Share Posted February 26, 2010 (edited) ...Does that sound (like) a plan or a waste of time... That actually sound like a solid plan. Removable and well designed. Cost vs. performance, would seem to be inline, ...I know the right persons to have this done for the right kind of money (a little to none)... I bought a Mikuni Manifold that had a very similar set up for a Turbo. The manifold block (vacuum log) was only a few inches long though, but it was a square block and had a round bore in the center. Longer would be better, like stretching the entire length of the intake runners. It didn't use banjo bolts but tomato, tamato... ...I want to make a heavier linkage using 10 millimeter rose joints just to make it more solid than the 8 m.m. i have now... Beefier linkage is always a plus. I can't stand that stamp steel junk they include with the Cannon manifolds. I like to use 3/16" heim joints for the carb link arms, lots of adjustability and very beefy, and 3/8" as the risers for the throttle shaft rod. I had a Lynx manifold once years ago, and if memory serves me they are only missing the bungs on cylinders one and five. Is that correct? Mine too had those stupid plastic heims, fortunately for me the threads were all stripped out and I was forced (not reluctantly by the way) to replace them with all steel units... and I too stepped up the throttle shaft rod size. That really is an odd location for the throttle shaft. TWM, Mikuni and others got it right by stuffing the throttle shaft towers close to the carb mounting flange. Hey, those look like a set of Dellorto DHLA hidden under those triple bore throttle bodies. What are those throttle bodies from anyhow? What's the bore size? Do share. Edited February 26, 2010 by brokebolt Quote Link to comment Share on other sites More sharing options...
2fast2Z Posted February 26, 2010 Author Share Posted February 26, 2010 Hey, those look like a set of Dellorto DHLA hidden under those triple bore throttle bodies. What are those throttle bodies from anyhow? What's the bore size? Do share. They are 40 Del's allright, got them as a bonus, they came with my nice manifold Didn't i say the photo was a teaser ?, okay then, i will share some, throttle bore is 43 m.m., center to center distance is 89 m.m. (very close to the Del's)come as a bundle with fuel rail stepper for idle control and injectors, they normally feed a 129 HP engine. They are meant for my L28 project, it all started with a engine fouling plugs, i started to look in to ignition, one thing lead to another, decided on EDIS and why not control EDIS with MS, not that more expensive than MegaJolt, when i have MS then why not go with ITB.......... Quote Link to comment Share on other sites More sharing options...
Tony D Posted February 27, 2010 Share Posted February 27, 2010 What are those ITB's? From a Bike? I was looking at stealing BMW ITBs since they sit out in the open and are rubber mounted, so with my Leatherman it would be easy pickens in most European Cities when I visit... But if you can give me a better thing to target (and it looks like you can) I'd like to know specifically where they came from! Quote Link to comment Share on other sites More sharing options...
2fast2Z Posted March 2, 2010 Author Share Posted March 2, 2010 Sorry for my late reply, didn't get a notificatoin. BMW ITB are to small (36 IIRC), but made by Bing as the set i posted a photo of. Quote Link to comment Share on other sites More sharing options...
2fast2Z Posted March 4, 2010 Author Share Posted March 4, 2010 Here is a little update, bungs have been milled, drilled and tapped, sorry for the crappy phone pics. Chris Quote Link to comment Share on other sites More sharing options...
onthego- Posted August 8, 2010 Share Posted August 8, 2010 (edited) Here is a little update, bungs have been milled, drilled and tapped, sorry for the crappy phone pics. Chris do you have an update on this with more pics? Im thinking about convderting a exta weber set with cannon intake to itbs... Edited August 8, 2010 by onthego- Quote Link to comment Share on other sites More sharing options...
madkaw Posted December 14, 2011 Share Posted December 14, 2011 I am reviving this thread looking for opinions on vacuum line size on the log . With my set up I could go from 1/8 all the way to 3/8 or better, but not sure if bigger is better or visa-versa? Quote Link to comment Share on other sites More sharing options...
Tony D Posted December 14, 2011 Share Posted December 14, 2011 I replied on your other thread. The 1/8" NPT holes will accept a fitting with a 1/4" diameter through-hole and 5/16" barb if you can find them (like I did)... Quote Link to comment Share on other sites More sharing options...
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