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| 66 coupe |
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yeah fair enough...
i think having a single rod, so far from the cyl head you might have issues with the rod causing the throttle blades to bind as everything heats up. You will find the ally runners will move enough with engine bay temps / expansion that it will push the throttle blades into the sides of the throttle bores. This certainly happens if you have the joiners too tight between pairs of IDF's on V8's. You need some end float between them all. |
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| jimmyd |
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66 coupe wrote: yeah fair enough... i think having a single rod, so far from the cyl head you might have issues with the rod causing the throttle blades to bind as everything heats up. You will find the ally runners will move enough with engine bay temps / expansion that it will push the throttle blades into the sides of the throttle bores. This certainly happens if you have the joiners too tight between pairs of IDF's on V8's. You need some end float between them all. I cam across the same issue with dual idfs on the RS2000 before I reconfigured the linkages - I'm interested to see if the issue surfaces on this build Cheers |
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| tickford_6 |
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Posts: 6449 Joined: 11th Nov 2004 |
66 coupe wrote: are you using 6 individual throttles, or is the spacing suitable for 3x IDF's or DCOE's Syncing 6 throttles is going to be a pain, you will need adjustable linkages (joiner/balancers) between each one. I think he is going to have them made on a common shaft, EFI Hardware will make them to what ever centers and sizes you want. |
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| 66 coupe |
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tickford_6 - yes i know that, but what im saying is that on a common shaft, the throttle blades will be pushed into the sides of the throttle bores with expansion. This could / will be an issue causing the throttle to bind.
It would be a shame to see all the work done, and then have this issue, since i've seen this issue first hand, and jimmyd has too, this is a heads up, that he probably should use individial shafts, or 3 pairs of 2 (does that make sense??? 3x2) with joiners inbetween |
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| dsyfer |
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66 coupe wrote: yeah fair enough... i think having a single rod, so far from the cyl head you might have issues with the rod causing the throttle blades to bind as everything heats up. You will find the ally runners will move enough with engine bay temps / expansion that it will push the throttle blades into the sides of the throttle bores. This certainly happens if you have the joiners too tight between pairs of IDF's on V8's. You need some end float between them all. Thanks, some food for thought, might have a chat with EFI tomorrow, the manifold will only be 50mm in depth, so the butterflies and rod should only be 75mm away from the head, what about if I have individual mounts off of each runner for the TB's rather than joining the plate between the bodies, would this help with expansion issues a bit? |
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| 66 coupe |
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having them individual would make it worse, having plates between two will tend to hold them in place, but ally and brass have different expansion rates.
Personally, id suggest 3 lots of 2 with couplers / balancers inbetween just to be safe. |
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| dsyfer |
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Anyone know what is the better thread size for the M8 thread is 1.0mm or 1.25mm?
The tap I have is the corse thread 1.25mm, but are wondering if I should use the finer thread 1.0 M8 for the manifold where the throttle bodies bolt on? |
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| jimmyd |
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Minimal difference in shear strength at this size - 1.00 @ 31kN vs 1.25 @ 29kN. Finer pitch more prone to damage though
Cheers James |
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| FLASH |
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66 coupe wrote: Personally, id suggest 3 lots of 2 with couplers / balancers inbetween just to be safe. Possibly? would a balance adjuster between each be more beneficial? although allot more fiddly to manifacture i know, but then you can use a manometer on the balance line between each T/B to synchronize them for perfect acuracy? You can just tune them 1 & 2, 3 & 4, 5 & 6, then 2 & 3 and 4 & 5. Just throwing out ideas. I tune my bikes like this. Great thread btw, its rare i read one from start to finish. Very informative.
_________________ FALCAHOLIC |
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| jimmyd |
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FLASH wrote: 66 coupe wrote: Personally, id suggest 3 lots of 2 with couplers / balancers inbetween just to be safe. Possibly? would a balance adjuster between each be more beneficial? although allot more fiddly to manifacture i know, but then you can use a manometer on the balance line between each T/B to synchronize them for perfect acuracy? You can just tune them 1 & 2, 3 & 4, 5 & 6, then 2 & 3 and 4 & 5. Just throwing out ideas. I tune my bikes like this. Great thread btw, its rare i read one from start to finish. Very informative. I believe the plan is to use the air bypass screws to achieve this - sound in theory with EFI, but fraught with danger on carberettors as it tends to throw out partial throttle response due to varying fluid dynamics around progression holes..... Cheers James |
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| 66 coupe |
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dsyfer wrote: Anyone know what is the better thread size for the M8 thread is 1.0mm or 1.25mm? The tap I have is the corse thread 1.25mm, but are wondering if I should use the finer thread 1.0 M8 for the manifold where the throttle bodies bolt on? You wont need a lot of tension if they have o-ring bases, so either will be ok, I normally use a thin skim of grease, or loctite flange sealant around the bases, and with a spring washer just nip it up. As far as syncing them, seeing you have air bypass screws its not as critical, without the screws its a bit harder to get them all balanced. A central plenum will help with this, even if you weld in a 1" ID tube under and across all 6 runners. You can also take your brake vac from this. Some v8 intakes have a central vacuum plenum in the valley section with 6-8mm holes to each port. you can set them all in sync with a very thin feeler gauge between the plate and bore. |
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| FLASH |
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jimmyd wrote: FLASH wrote: 66 coupe wrote: Personally, id suggest 3 lots of 2 with couplers / balancers inbetween just to be safe. Possibly? would a balance adjuster between each be more beneficial? although allot more fiddly to manifacture i know, but then you can use a manometer on the balance line between each T/B to synchronize them for perfect acuracy? You can just tune them 1 & 2, 3 & 4, 5 & 6, then 2 & 3 and 4 & 5. Just throwing out ideas. I tune my bikes like this. Great thread btw, its rare i read one from start to finish. Very informative. I believe the plan is to use the air bypass screws to achieve this - sound in theory with EFI, but fraught with danger on carberettors as it tends to throw out partial throttle response due to varying fluid dynamics around progression holes..... Cheers James Ah yes, makes more sense.
_________________ FALCAHOLIC |
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| ED_XR6_5 SPEED |
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hi dsyfer, i have been watchin this thread for a while now, man some thought has gone into this. anyway i was surfing the net just before and found this website, i thought it might be of some help maybe
http://extrudabody.com/TechInfo/Throttle.html cheers, Tomo
_________________ 98%of city drivers will say ''holly s**t'' befor going into a ditch in a snowstorm and 98%of country drivers will say ''hold my beer and watch this'' |
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| dsyfer |
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ED_XR6_5 SPEED wrote: hi dsyfer, i have been watchin this thread for a while now, man some thought has gone into this. anyway i was surfing the net just before and found this website, i thought it might be of some help maybe http://extrudabody.com/TechInfo/Throttle.html cheers, Tomo Hey cheers Tomo, I found them originally when I was looking for throttle bodies, but never found the tech bits. |
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| dsyfer |
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Found some time to get a bit more of the manifold happening.
First of the runners finished, tapers from 48mm to 44mm, you can see the test flange I cutout of MDF on the laser at work underneath.  Tried a number of ways of getting the taper correct; exhaust place pipe expander left a big hump in the runner. Finally found the correct mandrel at work.  However, after looking at the existing original manifold flange I have decided to fabricate an entire manifold, rather than using the part of the existing, number of reasons; don't have to worry about welding the 6060 runners to the factory cast alloy, will look better, will be easier to match port to head and runners, can make the manifold shorter. EFI Hardware have weld in injector bosses.  Now off to make the rest of the runners. |
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