XR7 Dave
Registered User
As we work on a new cylinder head design we are also faced with intake manifold questions that need to be addressed in an orderly manner so lets take that discussion here so that we can do the topic justice and the other threads can stay on track.
Before stating that the stock intake is crap, you have to look at the design considerations that influence what you can do with it. We all know that hood clearance is a major issue. How do you package something under the hood of the SC without making radical changes to the rest of the engine bay and the car in general? We already know that a 3/4" raised top comes real close to the hood on an 89-93 model SC. Since logic dictates that people are going to use M90's and 3/4" raised tops on their SC's, then we have to ask, do we want to design an intake manifold that is less than 1/4" taller than the stock unit? Is it worth the time and $$? What can we do to the existing design that will make it better without raising the lid?
People talk about runners, diffusers, etc, but where do we put these devices and what added restriction are they going to cause in an area where space is too small already? Putting any kind of a runner in the stock lower intake will be extremely restrictive. There are reasons why most blower cars use open plenums.
Gut reaction tells me that only through testing can one expect to make real progress on something like this. As you can see from our lovely exhaust manifold discussion there are many theories and ideas, some of which are very dearly held, and which vary greatly among the group of us.
Intake manifold design is an art. The fact remains that we do not have the resources among us to follow through with a lot of testing on a manifold that is really intended only for people with stock hoods and M90's on their cars. Does that market really need a new intake?
I don't want to sell anyone or anything short, but we all need to look at what we are asking and what it means. If we spend our money on an intake that fits the stock SC, then how does that benefit those who really want to go fast and are ready to ditch (or already have) the stock hood and try something really new?
These are questions that need to be answered. If you have opinions on this you need to speak up now. Keep also in mind that opinions are one thing, but if you/we don't have or cannot find answers then we are not going to entertain ideas that we can't act on.
A package deal seems like a great idea, but what do we really want? Do we want a new manifold that simply bolts in place of the old one with symetrical ports sized to match the new heads? Should it accept the old return adapter or do we need a new one of those also?
Speak.
Before stating that the stock intake is crap, you have to look at the design considerations that influence what you can do with it. We all know that hood clearance is a major issue. How do you package something under the hood of the SC without making radical changes to the rest of the engine bay and the car in general? We already know that a 3/4" raised top comes real close to the hood on an 89-93 model SC. Since logic dictates that people are going to use M90's and 3/4" raised tops on their SC's, then we have to ask, do we want to design an intake manifold that is less than 1/4" taller than the stock unit? Is it worth the time and $$? What can we do to the existing design that will make it better without raising the lid?
People talk about runners, diffusers, etc, but where do we put these devices and what added restriction are they going to cause in an area where space is too small already? Putting any kind of a runner in the stock lower intake will be extremely restrictive. There are reasons why most blower cars use open plenums.
Gut reaction tells me that only through testing can one expect to make real progress on something like this. As you can see from our lovely exhaust manifold discussion there are many theories and ideas, some of which are very dearly held, and which vary greatly among the group of us.
Intake manifold design is an art. The fact remains that we do not have the resources among us to follow through with a lot of testing on a manifold that is really intended only for people with stock hoods and M90's on their cars. Does that market really need a new intake?
I don't want to sell anyone or anything short, but we all need to look at what we are asking and what it means. If we spend our money on an intake that fits the stock SC, then how does that benefit those who really want to go fast and are ready to ditch (or already have) the stock hood and try something really new?
These are questions that need to be answered. If you have opinions on this you need to speak up now. Keep also in mind that opinions are one thing, but if you/we don't have or cannot find answers then we are not going to entertain ideas that we can't act on.
A package deal seems like a great idea, but what do we really want? Do we want a new manifold that simply bolts in place of the old one with symetrical ports sized to match the new heads? Should it accept the old return adapter or do we need a new one of those also?
Speak.