Straight vs Merge Collector

[MadBill]

If the end of the tube was cut at 45°, resulting in an oval tube exit angled 90° to the exhaust flow, I'd think it would behave the same as the design in question. But then it would basically be the same as common present designs. Maybe the only magic is the throat location in a merge collector.

BTW, with a 45° angled tube, the gas flow path would be similar to that around a 'streamlined body', which has a Cd of ~1/10th that of a cylinder...

PS: could you post the link to that thread to spare us slackers the need to do our own searches?

[RDY4WAR]

If the end of the tube was cut at 45°, resulting in an oval tube exit angled 90° to the exhaust flow, I'd think it would behave the same as the design in question. But then it would basically be the same as common present designs. Maybe the only magic is the throat location in a merge collector.

BTW, with a 45° angled tube, the gas flow path would be similar to that around a 'streamlined body', which has a Cd of ~1/10th that of a cylinder...

PS: could you post the link to that thread to spare us slackers the need to do our own searches?

viewtopic.php?f=1&t=16468&start=30

Maybe I'll try it that way by installing far enough in that it is right in the center of the throat.

[mag2555]

I don’t think your running enough Cam / overlap to fully make use of the merge collectors making enough vacuum level at TDC to start the intake draw early enough to get a good VE kick!

I mean you will get some boost in power, but to me it hinges on the Dollar to power gain ratio.

[RDY4WAR]

I don’t think your running enough Cam / overlap to fully make use of the merge collectors making enough vacuum level at TDC to start the intake draw early enough to get a good VE kick!

I mean you will get some boost in power, but to me it hinges on the Dollar to power gain ratio.

I'm thinking that as well.

[skinny z]

I don’t think your running enough Cam / overlap to fully make use of the merge collectors making enough vacuum level at TDC to start the intake draw early enough to get a good VE kick!

I mean you will get some boost in power, but to me it hinges on the Dollar to power gain ratio.

I'm thinking that as well.

What IS your overlap by the way? Seat to seat?

[splinter]

Merged...

IMG_E5777.JPG

IMG_E5779.JPG

[RDY4WAR]

I don’t think your running enough Cam / overlap to fully make use of the merge collectors making enough vacuum level at TDC to start the intake draw early enough to get a good VE kick!

I mean you will get some boost in power, but to me it hinges on the Dollar to power gain ratio.

I'm thinking that as well.

What IS your overlap by the way? Seat to seat?

I'm not exactly sure as GM only publishes the .050" numbers. I've heard 268/278 @ .003" but haven't actually checked it.

That would be 40° overlap at seat and -28.5° at .050".

[skinny z]

I'm thinking that as well.

What IS your overlap by the way? Seat to seat?

I'm not exactly sure as GM only publishes the .050" numbers. I've heard 268/278 @ .003" but haven't actually checked it.

That would be 40° overlap at seat and -28.5° at .050".

I don’t think your running enough Cam / overlap to fully make use of the merge collectors making enough vacuum level at TDC to start the intake draw early enough to get a good VE kick!

I mean you will get some boost in power, but to me it hinges on the Dollar to power gain ratio.

40°? Yeah, that's certainly not a lot for scavenging as mentioned.
Is that a 116 LSA?

[RDY4WAR]

40°? Yeah, that's certainly not a lot for scavenging as mentioned.
Is that a 116 LSA?

116.5

Not much scavenging at all.

[mag2555]

I’am thinking that getting your tuned lenght maxed out with the collectors you have now will be your best bang for the buck deal.

[RW TECH]

Nice gains though not really relevant here. The car never sees peak torque at any point, much less below that.

Does this car have a torque converter? If yes it may be faster with the added TQ below peak.

On my own car there is a night & day difference between having a dyno spark cal in the car vs about 5° spark added from 3000-5800 RPM with a converter that flashes to ~6500 RPM.

At the pasted link at the bottom, scroll to 2:56:50, sound on, and right lane.

This is the run after I put extra spark below stall, prior run was lazy with front end pinned to the ground. Keep in mind, the slow run had best dyno power spark in it.

https://www.youtube.com/watch?v=lwzUxja5N4k

[RDY4WAR]

Nice gains though not really relevant here. The car never sees peak torque at any point, much less below that.

Does this car have a torque converter? If yes it may be faster with the added TQ below peak.

On my own car there is a night & day difference between having a dyno spark cal in the car vs about 5° spark added from 3000-5800 RPM with a converter that flashes to ~6500 RPM.

At the pasted link at the bottom, scroll to 2:56:50, sound on, and right lane.

This is the run after I put extra spark below stall, prior run was lazy with front end pinned to the ground. Keep in mind, the slow run had best dyno power spark in it.

https://www.youtube.com/watch?v=lwzUxja5N4k

That would make sense as the faster rev with no load would probably like a lot of timing.

[RW TECH]

That would make sense as the faster rev with no load would probably like a lot of timing.

Yes, It pounded the converter & ran 0.15 quicker, even though the areas changed were well below converter stall RPM.

[RDY4WAR]

The quicker the engine revs, the harder it will hit the converter so it makes sense. It may be worth considering then.

[Bill Chase]

https://www.speedwaymotors.com/Dynatech ... 52671.html

Might try experimenting with these. Take the time to call Hendren racing and talk to them, the product I listed is designed by them and licensed for production to Dynatech. So they will talk to you. They were very helpful in giving me a starting point to locate them. Also many threads here discussing them, if done right good for 10-20 ft pounds down low with no loss up top. In my case (383 sbc 26" primaries, 8" long 3" collectors, 10.3 scr, 276/280@ .006 228/232@.050 .576/.576 110 lsa/107 icl) they recommend either right at the header flange, or experiment by putting them at the first length pipe max suggests for my combo. Many have discussed the use of these types of anti reversion cans here with very favorable results. Also, they will lower part throttle noise substantially, so for a street car they made sense to use.