Supercharger conversion dual TB's... Why?
10-02-2011, 09:55 AM
#1
Supercharger conversion dual TB's... Why?
I was looking at supercharger conversions for a friends MX5 and they all run a dual TB setup, one before the SC and then the stock TB.
Why is this? Whats wrong with just using the stock TB like if you were fitting a turbo?
Thanks!
Why is this? Whats wrong with just using the stock TB like if you were fitting a turbo?
Thanks!
10-02-2011, 10:16 AM
#2
Turbocharging Technician
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because the supercharger will be more efficoent when its pumping less (in a vacuum) on light throttle. IE when you are cruising it will make little boost as it is operating in a vacuum.
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10-02-2011, 11:34 AM
#10
Advanced PassionFord User
It may be a by pass valve not throttle body.
The normal way is a throttle before the supercharger with a by pass valve around the supercharger. The bypass valve is vac operated. So on closed or light throttle the supercharger uses less power. Then under load the bypass is closed and the supercharger gives full output.
But there are lots of ways to set them up. Depends if you want instant power or efficient running.
The normal way is a throttle before the supercharger with a by pass valve around the supercharger. The bypass valve is vac operated. So on closed or light throttle the supercharger uses less power. Then under load the bypass is closed and the supercharger gives full output.
But there are lots of ways to set them up. Depends if you want instant power or efficient running.
10-02-2011, 12:42 PM
#11
I've found that life I needed.. It's HERE!!
depends on application, i'm going supercharger because i want big power and no lag, modern supercharging is quite good though compared to yesteryear, they are getting very efficient, problem is most people are brain washed into turbos being better and won't look past them
10-02-2011, 12:47 PM
#12
It may be a by pass valve not throttle body.
The normal way is a throttle before the supercharger with a by pass valve around the supercharger. The bypass valve is vac operated. So on closed or light throttle the supercharger uses less power. Then under load the bypass is closed and the supercharger gives full output.
But there are lots of ways to set them up. Depends if you want instant power or efficient running.
The normal way is a throttle before the supercharger with a by pass valve around the supercharger. The bypass valve is vac operated. So on closed or light throttle the supercharger uses less power. Then under load the bypass is closed and the supercharger gives full output.
But there are lots of ways to set them up. Depends if you want instant power or efficient running.
10-02-2011, 12:50 PM
#13
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Of course the application is of importance, but on a road car (this is what most of us are talking about) with rising fuel costs, a turbo offers better efficiency over a supercharger. And with regard to modern and old, the very same can be said with turbos. Turbos work very well in almost all applications and offer a simplisic way of achieving more horespower, thats why most forced induction road cars use turbos in either petrol or diesel application.
10-02-2011, 01:00 PM
#14
cossie fan (unluckerly)
10-02-2011, 01:35 PM
#15
Advanced PassionFord User
If you didn't run 2 tb's you'd need to run either a dump valve (which would really get on your tits) or face bad idling and your aux belt stretching all the time.
Still won't be as responsive as a s/c
Still won't be as responsive as a s/c
10-02-2011, 01:42 PM
#16
cossie fan (unluckerly)
Still won't be as responsive as a s/c[/quote] still as responsive as u will ever need on the road if u have the right set up and its mapped by someone who knows what there doing theres cars about now with twin scroll set ups that make 2.6 bar of boost in 5th by 46oorpm that is responsive
10-02-2011, 01:53 PM
#17
I've found that life I needed.. It's HERE!!
still as responsive as u will ever need on the road if u have the right set up and its mapped by someone who knows what there doing theres cars about now with twin scroll set ups that make 2.6 bar of boost in 5th by 46oorpm that is responsive [/QUOTE]
a supercharger is at about 90% torque by 1500rpm, thats responce, well at least thats what they say about the XJR Jags, and thats running a crap supercharger
[/QUOTE]a supercharger is at about 90% torque by 1500rpm, thats responce, well at least thats what they say about the XJR Jags, and thats running a crap supercharger
10-02-2011, 03:08 PM
#19
Advanced PassionFord User
Look at the torque curve, how many turbo cars have them as flat?
10-02-2011, 03:22 PM
#20
cossie fan (unluckerly)
lol your kidding right theres no torque or bhp there look up rod tarrys grapth or mad ades looking at your grapth u have around 130 ft lb at 3500 rpm but someone like rod has about 300lb ft by then and he says his turbo is laggy as its for top speed yet by 5000rpm he has 600lb ft
Last edited by ajamesc; 10-02-2011 at 03:48 PM.
lol
10-02-2011, 04:45 PM
#22
cossie fan (unluckerly)
10-02-2011, 05:17 PM
#24
It Wasnt Me!
I've saw a compound charged CA18 nissan engine, it had throtle before suprecharger, then supercharger into turbo then turbo into inlet, b ut between supercharger and turbo, it had a throtle, which was for the changeover from s/c to turbo at the correct RPM when the turbo spooled the S/C became a restriction so it bypased with the extra throtle. worked V.well too.
I suppose if your S.C is small enough there is an arguement for a 2nd throtle as it could become a restriction at high rpm, maybe? I dunno.
I suppose if your S.C is small enough there is an arguement for a 2nd throtle as it could become a restriction at high rpm, maybe? I dunno.
Last edited by vroooom ptssssh; 10-02-2011 at 05:19 PM.
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