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Home > Help Needed / General Tech Chat > Blow through SC problems | |||||||
1909 Posts Member #: 9764 Post Whore Northamptonshire. |
25th Jan, 2015 at 09:41:19pm
What is a the main issue with SC blow through setups again
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
25th Jan, 2015 at 10:44:06pm
With a carb you have the butterfly after the blower so you need to dump the excess pressure when the throttle is closed. I would imagine it might be hard to control the fueling on part throttle. I dont know of anyone whos done it with a carb. |
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1909 Posts Member #: 9764 Post Whore Northamptonshire. |
26th Jan, 2015 at 01:00:14am
I'm sure the throttle has got to be before the charger on a blow through to work off memory
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1767 Posts Member #: 9165 Previously josh4444 Australia, brisbane |
26th Jan, 2015 at 03:36:18am
how do the v8 guys do it then dont they have blower carb intake engine ? |
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
26th Jan, 2015 at 10:16:26am
It doesnt need to go before the blower, but if you have it after you need a bypass much like a dump valve on a turbo. I was designing a system for my Fiesta that had the throttle after the blower and was going to use a normal recirc type dump valve for the bypass but the project has ended up on the back burner so couldn't say if it will work. It will be injected too of course!
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11046 Posts Member #: 965 Post Whore Preston On The Brook |
26th Jan, 2015 at 10:36:43am
The big V8s work either way but when the carb is after the blower there is another throttle infront if the blower to keep the pressure ratio across the blower low. On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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3577 Posts Member #: 655 Post Whore Northern Ireland |
26th Jan, 2015 at 11:51:27am
On 26th Jan, 2015 Chalkie said:
I'm sure the throttle has got to be before the charger on a blow through to work off memory Trying to find out how bmw did it on the cooper s I With fuel injection lol. I'm sure you could do it ok as long as the air bypass was sufficient so there would never be excessive air in front of the carb at low loads. But it could be tricky. Most common route with a carb is such through. 9.85 @ 145mph
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1909 Posts Member #: 9764 Post Whore Northamptonshire. |
26th Jan, 2015 at 07:19:34pm
Yeah I now bmw used fuel injection but they put a bypass valve in aswell after the throttle
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3577 Posts Member #: 655 Post Whore Northern Ireland |
26th Jan, 2015 at 07:22:25pm
On 26th Jan, 2015 Chalkie said:
Yeah I now bmw used fuel injection but they put a bypass valve in aswell after the throttle and I don't like suck through fuel across the blades. Podifold made one but i seen he didn't make what he expected All blower setups will have a bypass valve. And I'd imagine the Bini has the throttle blade in front of the blower ? And sucking fuel across the rotors is a good thing, as it helps keep them cool, which also means cooler charge temps. 9.85 @ 145mph
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1750 Posts Member #: 10190 Post Whore belgium |
26th Jan, 2015 at 09:49:14pm
but doesn't it make fuel go back into drops instead of vapour? you can do anything if you set your mind to it...
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11046 Posts Member #: 965 Post Whore Preston On The Brook |
26th Jan, 2015 at 10:04:01pm
Blow through is just wrong with an open supercharger intake On 26th Oct, 2004 TurboDave16v said:
Is it A-Series only? I think it should be... So when some joey comes on here about how his 16v turbo vauxhall is great compared to ours, he can be given the 'bird'... On 26th Oct, 2004 Tom Fenton said:
Yep I agree with TD........ |
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
26th Jan, 2015 at 11:41:12pm
If you set it up right the blower just free wheels when the throttle is shut either way round, assuming you have a working bypass that is. My only uncertainty is if it will be too hard to set up correctly with a carb.
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
26th Jan, 2015 at 11:45:55pm
Then again it works with a turbo so why not! |
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3577 Posts Member #: 655 Post Whore Northern Ireland |
26th Jan, 2015 at 11:56:06pm
On 26th Jan, 2015 Rammie2000 said:
but doesn't it make fuel go back into drops instead of vapour? No idea what it does...but the yanks have been doing it for decades and it works. When there are other design issues with a blow through install, and little real benefit...sometimes isnt worth trying to fix something that isnt broke when it really isnt going to gain you anything. The only reason to go to the effort of blow through would be to allow the addition of an intercooler...and that in itself creates even more issues and work. 9.85 @ 145mph
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
27th Jan, 2015 at 09:05:21am
Its a lot better for your charge temp to be running an intercooler!!
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3577 Posts Member #: 655 Post Whore Northern Ireland |
27th Jan, 2015 at 11:00:17am
On 27th Jan, 2015 slater said:
Its a lot better for your charge temp to be running an intercooler!! This assumes you're running enough boost to warrant an intercooler. A lot of Rootes style simply dont. Some opt for a small heat exchanger underneath etc. But when you try to design a blow through using one and a carb, that in itself raises issues. Doesnt matter what approach you take, you could say there are compromises with them all. Just pick what is easiest for the individual user that gives them the results they want 9.85 @ 145mph
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1909 Posts Member #: 9764 Post Whore Northamptonshire. |
27th Jan, 2015 at 09:17:45pm
I want to supercharge cause i love the sound of them, also low down torque
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1750 Posts Member #: 10190 Post Whore belgium |
27th Jan, 2015 at 09:50:11pm
it just makes me wonder... anyone ever heard of seen or dreamed of a twin charger. like charger for low down torque and then turbo for the high revs... or even twin turbo's? you can do anything if you set your mind to it...
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1030 Posts Member #: 1291 Post Whore Suffolk / Birmingham |
27th Jan, 2015 at 11:38:48pm
Yeh you can do that. Lancia Delta S4 is probably the most famous example. Wonder where they put the throttle! |
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293 Posts Member #: 10010 Senior Member Northants |
27th Jan, 2015 at 11:47:51pm
VW do an engine that has both a supercharger and turbocharger.
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3577 Posts Member #: 655 Post Whore Northern Ireland |
28th Jan, 2015 at 12:36:12am
On 27th Jan, 2015 Rammie2000 said:
it just makes me wonder... anyone ever heard of seen or dreamed of a twin charger. like charger for low down torque and then turbo for the high revs... or even twin turbo's? Quite a few have done it, but it can be complicated to get nice. As for throttle placement....just one throttle ? There are a multitude of ways of doing it...the biggest problem here is trying to retain a carburettor. Almost all twin setups will be fuel injected. If you want fast spool and turbo...a small diesel VNT turbo is probably the simplest option, along with a good ecu to control the turbo vanes 9.85 @ 145mph
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1909 Posts Member #: 9764 Post Whore Northamptonshire. |
29th Jan, 2015 at 08:36:41am
I don't want to keep the carb I don't mind running injection, could you run a blow through supercharger like a turbo set up with a plenum camber and a dump Valve? |
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1767 Posts Member #: 9165 Previously josh4444 Australia, brisbane |
29th Jan, 2015 at 09:36:51am
at the end of the day its just a belt driven turbo and its just boost so why should anything be diffrent? make some plates with pipes comeing in and out like a turbo and plumb it like a turbo the harder bit when compared to turbo is mounting and the belt drive
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Site Admin 15300 Posts Member #: 337 Fearless Tom Fenton, Avon Park 2007 & 2008 class D winner & TM legend. |
29th Jan, 2015 at 09:39:27am
Wrong, its totally different, close the throttle on a turbo and the boost soon falls away as the exhaust gasses subside, close the throttle on a supercharger and its still pushing just the same amount of boost out as its mechanically different.
On 29th Nov, 2016 madmk1 said:
On 28th Nov, 2016 Rob Gavin said:
I refuse to pay for anything else Like fuel 😂😂 |
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1767 Posts Member #: 9165 Previously josh4444 Australia, brisbane |
29th Jan, 2015 at 10:03:14am
youll still have a bov just like a turbo whont that take care of pressure behind the butterfly? butterfly closes pulls vacuum opens bov dumping the pressure so long as its able to pass the full flow from the blower
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