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Butterfly valves...

Quicksight

CEG'er
Joined
Mar 11, 2014
Messages
219
Location
Ripley, WV
Just a quick question: I've known for a while that the CSVTs have a IMRC that opens up secondary air valleys. At around 3200 RPMs these open up and kinda give a turbo boost feel. However before those open up the car feels SOO slow it's emberassing lol. What would happen if I removed the circles in the seconday intake runners to have them open at ALL RPMS? Theoretically it would allow more air to the motor!
 
If you pin them open, you lose all your low-end torque.

The closed runners GREATLY IMPROVE low-end torque response. The long runners give low intake charge volume and high velocity, which is what the engine needs up to 3500 RPM's or so. "More air" is not always the answer. Velocity is CRUCIAL.

Sounds like you're either A: expecting too much, or B: experiencing a problem. Make sure the two banks of butterflies are connected and operating in tandem like they are supposed to.
 
If you pin them open, you lose all your low-end torque.

The closed runners GREATLY IMPROVE low-end torque response. The long runners give low intake charge volume and high velocity, which is what the engine needs up to 3500 RPM's or so. "More air" is not always the answer. Velocity is CRUCIAL.

Sounds like you're either A: expecting too much, or B: experiencing a problem. Make sure the two banks of butterflies are connected and operating in tandem like they are supposed to.

Well back when my car was running like a top, I was disappointed in the low end power, considering my car was an SVT I expected more low end torque. still fun to drive tho.

I haven't really learned about velocity. I'll have to read up on that to understand how it effects the engine. Thanks

I always thought more air was BEST :)
 
Basically it restricts the air since it has less space to travel thru. After 3500 RPMS you need more volume cause it's suckin more. So the answer to my question is: I NEED A SUPERCHARGER!
 
I think you need to understand the engine alittle more before a supercharger. The SVT was mean to be a high reving engine. It make its peak hp numbers at redline. The secondaries are designed to give more torque down low and they then open to provide more air on the top end. The SVT has no more torque below ~3500 rpm then a SE with the V6. The difference again it above that 3500 rpm point. I good y-pipe and exhaust I do believe will increase low end torque.


Also supercharger make the most power at the top end iirc.
 
My first contour (95) had the IMRC break and it had idle and cold drivability problems. Now take a full 3L swap and tune for it and you don't have any problem not having an IMRC.
 
I think you need to understand the engine alittle more before a supercharger. The SVT was mean to be a high reving engine. It make its peak hp numbers at redline. The secondaries are designed to give more torque down low and they then open to provide more air on the top end. The SVT has no more torque below ~3500 rpm then a SE with the V6. The difference again it above that 3500 rpm point. I good y-pipe and exhaust I do believe will increase low end torque.

Also supercharger make the most power at the top end iirc.

Yea I need to learn more about how engines work : /
 
Don't worry about it, everyone has to start somewhere.


IIRC a supercharger creates boost in a more linear manor then a turbo. And since it is run off the crank then more engine rpm there is the fast the supercharge will spin and therefore make more boost. The turbo will spool up quicker but depending on the size it still isn't going to make a lot of torque until the point where the secondaries open.


Personally I never found the Duratec to lack low end torque. And once you have driven a turbo charged one you will understand why, there is no traction with a lot of lower end power.


There are plenty of mods that will help power for this engine, start reading around and then ask some questions.
 
Don't worry about it, everyone has to start somewhere.


IIRC a supercharger creates boost in a more linear manor then a turbo. And since it is run off the crank then more engine rpm there is the fast the supercharge will spin and therefore make more boost. The turbo will spool up quicker but depending on the size it still isn't going to make a lot of torque until the point where the secondaries open.


Personally I never found the Duratec to lack low end torque. And once you have driven a turbo charged one you will understand why, there is no traction with a lot of lower end power.


There are plenty of mods that will help power for this engine, start reading around and then ask some questions.

Ok thanks. I've always thought there weren't many mods for the CSVTs.. The only mod I've found is the MSDS headers (for the 3L) and they're 750$ new and you cant find them used. Also removing the catalytic converter I've found is popular. Other than that it seems people just get more HP with a tune which I don't have easy access to ...
 
There are plenty of mods for the Contour. Most are just marketed for other vehicles. Once you know which parts interchange(-ish) with other cars and what, if any, mods are needed to be a successful interchage, you'll find more than enough to make the Contour much more fun to drive than it already is.

A Port-mached 3L swap (with gutted secondaries no less!) was just the right amount of lowend for my SE. I wish I had put the SVT cams into it, or even the SE cams, but I goofed and thought I'd enjoy the mid-range power band of the 3L cams more... I was wrong :( But the car is still very fun to drive, even at high altitude!

The MSDS headers for the contour fit both 2.5 and 3.0 heads.
 
this is old, but you can call msds and get the headers bare, no gaskets and no mil elimnators for way under $750. they just dont advertise it on the site.
 
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