miles
Member
Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
User status: Offline
|
I cant see the problem with airflow to the small butterfly, its only for very low throttle positions when there is the most vacuum anyway.
The issue is the volume of the plendum chamber, which I dont know enough about to get into.
However inaccurate RR's might be, back to back tests under the same conditions are the only way things can really be compared.
|
miles
Member
Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
User status: Offline
|
quote:
Originally posted by Joff
quote:
Originally posted by Dan
in my eyes, cant c what difference can be made.
True, yet people still spend time removing the wedge from their butterfly and mesh from the air flow meter.
But you also think panel filters and induction kits work?
Its hardly loads of effort and zero expense in removing the wedge or mesh, which are both obvious obstructions...
|
Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
|
i can see how different filter types etc work
2 improve performance ya gotta get the air in, air filters are gonna slow air movement down etc etc, so is the best induction kit gonna b filterless, and straight in???? although not practical??
i cant c how the ecotech pipe can cause a loss in performance, due 2 not covering the small butterfly directly. as air is gonna be there, and there is no obstuctions, as with the wedge, mesh etc etc
Adult GiftsClick here to vist us
|
AK
Member
Registered: 5th Jul 00
Location: Aberdeen City
User status: Offline
|
air is going to be where?
The smaller butterfly is blocked off
|
ed
Member
Registered: 10th Sep 03
User status: Offline
|
Come on guys, this is GCSE chemestry... You should have paid attention when learning about the collision theory.
|
Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
|
air will still b able 2 get to the smaller butterfly, its not blocked off, its just covered (not getting air direct straight from the hose) and air is going to fill the throttle body.
if it was blocked off completely, a vacum effect would occur, and break the throttle body possibly??
Adult GiftsClick here to vist us
|
miles
Member
Registered: 25th Mar 02
Location: plymouth Drives: Astra Sport
User status: Offline
|
If the smaller one was blocked off completely then the engine wouldn't respond until the larger throttle body opened.
There is always a vacuum when the butterflies are closed, nothing breaks.
The throttle position sensor might confuse the ecu as well.
The best air filter for flow would be none?
[Edited on 19-12-2004 by miles]
|
Dan
Premium Member
Registered: 22nd Apr 02
Location: Gorleston on Sea, Norfolk
User status: Offline
|
thats very true, dint think about it like that lol.
Adult GiftsClick here to vist us
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by 1800ed
Come on guys, this is GCSE chemestry... You should have paid attention when learning about the collision theory.
Yes, instead I kept playing with the TV and VCR with my Casio remote control watch 
|
Siberia
Member
Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
|
quote:
Originally posted by Joff
quote:
Originally posted by M15T XE
anyone got a picture of a C20XE corsa with the SFI box fitted?
Don't think it's going to happen... I'm sure the Nova still needs the SFi box to be butchered to fit.
this is a mates of mines.....
as you can see some 'minor' bulkhead adjustment was needed
|
Nic Barnes
Member
Registered: 5th Apr 04
Location: nowhere near ginger people
User status: Offline
|
years ago on mig there were all the arguments about the actual size of the chamber of the sfi box and how reducing this wasnt the best idea, ie like the power cap, for initial throttle response.
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by Siberia
as you can see some 'minor' bulkhead adjustment was needed
PMSL - doesn't look like what's left qualifies as a bulkhead
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by muppetsport
years ago on mig there were all the arguments about the actual size of the chamber of the sfi box and how reducing this wasnt the best idea, ie like the power cap, for initial throttle response.
Exactly - that's the whole reason behind why a plenum chamber is needed.
|
ed
Member
Registered: 10th Sep 03
User status: Offline
|
Ok, perhaps I will be using a powercap rather than the SFi box
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by 1800ed
Ok, perhaps I will be using a powercap rather than the SFi box
No, the idea is to use the SFi box rather than a Powercap.
|
ed
Member
Registered: 10th Sep 03
User status: Offline
|
quote:
Originally posted by Joff
quote:
Originally posted by 1800ed
Ok, perhaps I will be using a powercap rather than the SFi box
No, the idea is to use the SFi box rather than a Powercap.
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
Modify the rear of the SFi box, then glassfibre over it to make it fit.
I'd imagine the volume would still be greater than a Powercap.
|
ed
Member
Registered: 10th Sep 03
User status: Offline
|
Could weld up a big plenum that fits the car properly without mods to the bulk head... Saying that. I don't know how tight it actuall is...
|
Nic Barnes
Member
Registered: 5th Apr 04
Location: nowhere near ginger people
User status: Offline
|
on my old nova xe, had to trim it. fixed it together with a flat plate of plastic and a glue gun. never came apart.
still though, you think about how much air is going to actually be inside of an sfi box, compared to the next to none a powercap will have.
reckon you gain about 2bhp with a powercap but actually loose out on low down tourque, rendering the product a waste of time. btw, ive got a powercap on the xe corsa, would rather have the sfi box. its obviously something that has been through r&d when vauxhall designed the engine, so its supposed to be that size and have that amount of air stored up in it.
just my opinions
|
ed
Member
Registered: 10th Sep 03
User status: Offline
|
How about if you had the powercap and some pipe attatched to a big box then to the air filter, so you had a remote SFi box.. Or does the plenum need to be on top of the throttle body?
|
Siberia
Member
Registered: 9th Oct 03
Location: Leprechaun Land Drives : Zafira GSI
User status: Offline
|
vaux did not design the engine to go into corsa's though.....
i think for the amount of difference the ecotek pipe will make to performance its alot better than cutting the bulkhead for the power cap or cutting away half the car to fit the sfi box...
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by 1800ed
How about if you had the powercap and some pipe attatched to a big box then to the air filter, so you had a remote SFi box.. Or does the plenum need to be on top of the throttle body?
As close to the tb as possible.
|
Joff
Member
Registered: 17th Oct 00
Location: Cambridgeshire
User status: Offline
|
quote:
Originally posted by Siberia
vaux did not design the engine to go into corsa's though.....
i think for the amount of difference the ecotek pipe will make to performance its alot better than cutting the bulkhead for the power cap or cutting away half the car to fit the sfi box...
Definately, which is why I've passed up two Powercaps to go for the Ecotec pipe
|
Nic Barnes
Member
Registered: 5th Apr 04
Location: nowhere near ginger people
User status: Offline
|
wel, is it????
in all honesty, if its costing yo power, why bother. if the engine is designed a certain way to make the 150-156bhp like it does, why change it and accept it instead of taking 5 mins with a pair of tin snips to your bulkhead.
you cant actually really see anything of where you have cut anyway once all the wiper linkage cover is back on.
the way i see it is, the sfi box works as a resevoir of air, ready and waiting for you to open the throttle. regardless, the ecotek pipe might fit better, but its restricting the flow to the small initial throttle butterfly. by changing the original design of airflow into the engine, remembering there are no turbos present to aid forced air, it will reuce the power output of the engine. not a great deal admitiedly, but enough in my opinion to make the engine not run as well as it would with the original design.
obviously, the solution is as the link above somewhere, throttle boddies.
|
Nic Barnes
Member
Registered: 5th Apr 04
Location: nowhere near ginger people
User status: Offline
|
quote:
------------------------------------------------------------------------
Originally posted by Siberia
vaux did not design the engine to go into corsa's though.....
i think for the amount of difference the ecotek pipe will make to performance its alot better than cutting the bulkhead for the power cap or cutting away half the car to fit the sfi box...
------------------------------------------------------------------------
when i put a c20let into me nova, i didnt just fit an f20 because it was easier, the engine was designed to have a 6speed, so with a bit weld, cutting and measuring, made a mount to fit it. id rather keep things the way they intended to be. if you go to the trouble of fitting the engine, whats a quick 5 mins with tin snips going to hurt you???????
|
