Larger throttle body
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Larger throttle body
I am wanting to get a bigger throttle body for my supercharged car. Any one had any sucess with one? There are plenty of larger ones availble but I am wondering how hard they would be too fit. Buying one looks like a cheaper option than getting the original bored out and I think they can only go 2.5mm bigger anyway.
warrior
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They already run a pretty large throttle body, you would have more restriction in other parts of the engine (notably the head) before you'd ever need to even consider upgrading the throttle body. In fact I'd go out on a whim and say unless you're pushing 350+hp you wouldn't even need to consider upgrading a throttlebody on a B6 engine.
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grain of salt anyone...what makes a supercharged car any different from a 250HP turbo car? absolute waste of money. the head flow is the restriction and then after that its the super high inlet temps that limit HP on a SC car.warrior wrote:Thats not what everything I have read says. They all say with a supercharged engine a larger throttle body makes quite a improvement. They say it is a weak link in any supercharger setup.
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Larger throttle body
hmm.. isn't a SC throttle body under vacuum ?
http://www.musclemustangfastfords.com/t ... ewall.html
It should be noted that throttle body sizing and maximum flow is less critical on a blow-through (centrifugal supercharger and turbo) application than a draw-through (positive displacement).
On 19 December 2012 20:04, SLYDIT <horsepower@mx5forum.co.nz (horsepower@mx5forum.co.nz)> wrote:
http://www.musclemustangfastfords.com/t ... ewall.html
It should be noted that throttle body sizing and maximum flow is less critical on a blow-through (centrifugal supercharger and turbo) application than a draw-through (positive displacement).
On 19 December 2012 20:04, SLYDIT <horsepower@mx5forum.co.nz (horsepower@mx5forum.co.nz)> wrote:
[Posted via external email]
warrior wrote:grain of salt anyone...what makes a supercharged car any different from a 250HP turbo car? absolute waste of money. the head flow is the restriction and then after that its the super high inlet temps that limit HP on a SC car.Thats not what everything I have read says. They all say with a supercharged engine a larger throttle body makes quite a improvement. They say it is a weak link in any supercharger setup.
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RED '90 TURBO. 192 RWHP. E MANAGE, KONI'S, 16"ADVAN RG'S WITH TOYO T1-R'S
Not sure where you are reading to say "everything" but i'm guessing turbo and SC are the same or similar requirements in the TB area and I have never read anything about limitations other than them failing and the butterfly screw going through engines....in very rare cases (constantly high revving 7200+ race engines...).
Guys, there is a HUGE diffrence between a turbo and a supercharged car. The turbo car runs the throttle body AFTER the turbo so the air going through the TB is pressurised.
A supercharged car runs the TB BEFORE the supercharger so the air going through the TB is NOT under pressure.
Think of a straw, the turbo car is forcing (at whatever PSI is it running) air through that straw but a Supercharged car is just breathing through that straw so it makes sence to make that straw bigger so more air can get in dosnt it?
So a larger TB makes a very big diffrence.
Have a look at all the supercharer kits for the commodores, mustangs, and even the new larger supercharger kit for the mx5, they ALL have larger throttle bodies, and this is for a good reason.
It is quite simple really.
A supercharged car runs the TB BEFORE the supercharger so the air going through the TB is NOT under pressure.
Think of a straw, the turbo car is forcing (at whatever PSI is it running) air through that straw but a Supercharged car is just breathing through that straw so it makes sence to make that straw bigger so more air can get in dosnt it?
So a larger TB makes a very big diffrence.
Have a look at all the supercharer kits for the commodores, mustangs, and even the new larger supercharger kit for the mx5, they ALL have larger throttle bodies, and this is for a good reason.
It is quite simple really.
warrior
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I've noticed the TB fitted before the supercharger on a cpl of builds, whats the deal?
I mean if the TB can handle it after the turbo why can't it handle it after a SC?
Im sure it has been done for a reason by people much smarter than me but still it seems odd from a laymen's point of few...
I mean if the TB can handle it after the turbo why can't it handle it after a SC?
Im sure it has been done for a reason by people much smarter than me but still it seems odd from a laymen's point of few...
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Sorry maybe I should have said a bypass valve. Here is the reason why superchargers have the throttle body after the supercharger and why a larger throttle body is worthwhile. "Because of what happens to the pressure in the intake system when you close the throttle. Unlike turbos, airflow cannot reverse backward through a fixed displacement supercharger. This means when you close the throttle under boost, theres a huge pressure spike in the intake and you can actually blow an intercooler apart. A large bypass valve may be able to solve the problem on a supercharger but nobody has been able to implement it well" quote from Keith Tanner.
warrior
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I dont have a bypass valve either....this performs the same job? as a BOV except it releases pressure back into the system before a turbo while a BOV generally vents to atmosphere although they can be recirculated like a by-pass valve i believe.
If a supercharger has the TB before it then does a vacumm arise once the throttle valve is closed? so no need for a BOV or by-pass valve whereas in a turbo its the opposite and you have pressure which if too great needs to be released..
If your SC is able to pump more air with a bigger TB then surely you need to increase the size of your whole intake tract as well.
Also you need to give thought to the 'Ram-effect of' faster air through a smaller tube can be better than to too big a tube with slower moving air.
So what i am trying to say is match pump to best airflow speed.
My set-up is so much nicer for having smaller IC tubing as i have matched turbo out-put...its all been a very experimental learning curve for me.
If a supercharger has the TB before it then does a vacumm arise once the throttle valve is closed? so no need for a BOV or by-pass valve whereas in a turbo its the opposite and you have pressure which if too great needs to be released..
If your SC is able to pump more air with a bigger TB then surely you need to increase the size of your whole intake tract as well.
Also you need to give thought to the 'Ram-effect of' faster air through a smaller tube can be better than to too big a tube with slower moving air.
So what i am trying to say is match pump to best airflow speed.
My set-up is so much nicer for having smaller IC tubing as i have matched turbo out-put...its all been a very experimental learning curve for me.
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Next obvious question...is it the mx5 TB or a TB that came with the SC?
If it came with the SC then it may be of a size thats already at its most efficient in relation to the out-put of the SC so to go bigger might not create any increase in power!?
If it came with the SC then it may be of a size thats already at its most efficient in relation to the out-put of the SC so to go bigger might not create any increase in power!?
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