A Gsr has 2 sets of butterflies in its intake manifold. what I want to know is the first set open and then the second set is opened also at a later rpm or is the first set open but closes when the second set opens............thanks

 

one set of butterflies. when motor is turned on the butterflies close. till about 5700rpm when they open up again.

vtec hits at 4400rpm on a GSR (b18C1)

 

I didnt get what u are trying to say which one is it
-are the fisrt set open still when the second set open up
-or do they close when the second set open

 

there is only one set of butterflies.

the long air track remains open at all times because it has NO butterflies
butterflies in the short air track open at 5750rpm

 

just to clarify a little



The butterflies default at open, they then close as engine starts and vacuum builds. At 5750 they are allowed to open again.....

 

get rid of the stock manifold and get a skunk 2 and illiminate the butterflies

 

so basically there is only one set of butterflies that open at high rpm and the so called first set does not exist it is just always open

 

Correct. You have both long and short runners, the longs are always open and the shorts open at higher RPM to extend breathing ability up to near redline.

 

it is also possible to remove the butterfly section if you want to go the cheap route. less travel and more air flow.

 

Thats fine if you have the cams to use it but otherwise you just kill your low end. The GSR manifold is a very impressive piece of engineering. It surprises me how quickly people dismiss it (without really understanding what it does)

P.S. Simply removing the butterflys all together doesn't do anything but hurt the performance. This has been well documented. Do a search.

Mike


[Modified by 92sleepR, 3:00 PM 2/5/2003]

 

yeah, ive documented the hell out of it Im currently working on a custom version of the gs-r manifold for Plan Bs engine. a lot of potential there.

 

but if the butterflies never open at high rpm the peak horsepower will decrease so if i dont care about the low end being lost for now i could have the butterflies always open until the skunk2 maniflod comes along which will be alright when punching it at a rolling start at high rpm


[Modified by NightHawkC5, 4:54 PM 2/5/2003]

 

again ... the butterflies are always open unless the system closes them. Disconnect the vacuum line and they will always be open..... when everything is wired up and hooked up correctly they are:
1. open when the car is off
2. close as soon as vacuum builds when car starts
3. open after 5750rpm

4-8 lb/ft of torque is lost when they are not working (not shutting)


[Modified by miahmouse, 9:17 PM 2/5/2003]

 

Really I'm interested with this. Would you mind if I see some pics of it? I was going to do a composite one, but I found out that most people don't know how good that piece really is. I love that manifold design. I just wish I could get a version with some custom sized runner's made. I don't feel like paying someone to port it, and not be even close to the dimension I want. I had this experience with a B16 manifold. It wasn't even in the ball park for the dimension's i told him I wanted. Then he said it flowed more air than the dimensions I wanted, but I wanted it to have a specific flow number the get torque not peak HP.

 

I said that if i didnt care about losing the low end i could leave the butterflies always open to get the high rpm horses i should get if the butterflies never open because of a p28 which doesnt open them. I could just punch it off a roll at 5700 and be alright right but i would lose low end until i get a skunk2 mani