200 CFM Research

[jsa]

[200cfm]

Thanks jsa for the clarification. I am starting to understand this better. It does look like some extra filling is occuring prior to the intake valve closing (IC) point on the 5500 graph. Appears to be peaking at 36 psi. That must be the turbo pressure continuing to fill the chamber beyond BDC. And I see that the timing port pulse for the intake valve opening (IO) is only slightly moving up and then bleeds off quickly as the valve moves further off the seat. This is really a nice software progam.

[jfholm]

[color=#000000]Good description by John (jsa) on what is happening. I have included a screen shot below to help visualize that very thing. The peak of the dip is at 600

[jfholm]

Now here is a screen shot at 5500 rpm, Notice the dip?

John

[jfholm]

Now just to give a little comparison, I have included two shots of my SBC which is naturally aspirated. I put the first on at 4000 rpm peak TQ and the second at 6000 rpm peak HP

John

[jsa]

[slracer]

The Lotus package used to be offered in a single cylinder variant as a FREE download. Don't know if it is still there or that was a promo? If that would help, worth checking.

Doug

[emarsh]

[jsa]

Yes Doug the single version is available free.

emarsh,
For ITB's I imagine it would be useful for the inlet side. Similarly open single pipes on the exhaust. Still a good learning tool but too limited for more complex manifolding.

[emarsh]

[200cfm]

Went on vacation and took the race car along. Just happened to be attached. . Ended up in Brown County, Indiana to attend the Studebaker/Hudson Orphan Drag event. My first out of state race. Had a ball on the road and at Nashville, Bean Blossom. Yes, they race in those foot hills.

Car ran fine and had no issues. Jetted down some and went faster than expected. Track is at about 960 ft and rather warm at 82-84 degrees. Made 5 runs and best was 6.340 @ 109.76. The track had excellent traction. Had my best ever 60 ft with a 1.407. Friendly and welcome home atmosphere from the track officials. Still running the fast port heads and still planning on better heads from the research experimental "red head." (tom c) Enjoy! Doing my share to stimulate the economy

Meet coordinator and his Lark R-1 Stude




R-2 Super Lark Stude



41 Commander Stude with Avanti R-2 engine



Hudson Street Rod with BBC 427



Hudson ProStock



Hudson Torque (4.5 stroke I believe)



Down town Nashville (Good wine and food at the "Hob Nob".)
(Also at the "Holy Cow".)

[jfholm]

NICE! Great pictures Tom.

Here is a current good discussion on turbos over at speedtalk


John

[200cfm]

Interesting! My system is using factory manifolds which would be "log type" design. I don't have individual runners to the turbo. And my heads have simezze ports for 3/5 and 4/6 exhaust. The stude exhaust port exit is square and not round. And the mating of the exhaust manifold along with the inside turns are also square and not round. But in one section the square casting converges into a trianglar shape which has to be "choke" point. Judging from the topic the design is not optimum. However Barnhouse states that a square tubing turn is superior to a round tubing turn. If that is so, then putting individual header tubings to my turbo might be introducing losses that the square manifold exit and turns don't have to contend with.

I'll see if I can post up a photo of the current exhausting plumbing. It's crude but it seems to work fine.

[jfholm]

besides your car goes fast enough to make me pee. I just thought it was interesting. Sometimes the people forget where "real" hot rodding starts and stops and just keep throwing bushel baskets of hundred dollar bills at it.

If I can find the pictures I will also post the ones I had of "square" tubing headers. Yes, they were built just like regular tube headers but with square tubing and square collectors.

John

[jfholm]

here is the picture of the square tube headers



John