What do you guys think??
Swap injection for carburation?
Moderator: martauto
I A guy I know swapped his whole injection system in a Volkswagen for 4 carburetors (4 cylinders). He proceeded to say he got huge power increase and that there were no downsides to his knowledge. He also said that if I would do the same thing to my e30 318is I'd go from about 134hp to 180hp!!
What do you guys think??
What do you guys think??
Apart from poor fuel economy and poor tractabiltiy, and a lighter wallet as you need, manifold, carbs, fuel pump, some why of making the sparks happen.
The gain would be the same as swaping ITB's as all your are doing is reducing the pressure drop across the intake system.
5-10bhp
When I put tripple weber's and a 6 branch manifold on a stock 325i the gain was 8bhp.
The gain would be the same as swaping ITB's as all your are doing is reducing the pressure drop across the intake system.
5-10bhp
When I put tripple weber's and a 6 branch manifold on a stock 325i the gain was 8bhp.
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e30topless
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you need to kick the guy you know in the bollox and tell him to stop talking shit !
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Brian28
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BMs are a bit more awkward than VWs. I'm putting R1 bike carbs on an M42, I'll let you know what the dyno says next month. The issue is that there isn't a vacum advance for the timing (like a traditional distributer). The ECU advances the timing when the engine is under load, takes signals from the AFM to do this. Without this, the car will only run the same ignition advance as at tickover, which is nowhere near enough. I'm planning a work around using a piggy back ECU and using the carb TPS as a dummy engine load sensor to advance the timing when the throttle is opened. A jump to 180 brake is bollock5. I have a pretty healthy rebuilt engine already, am adding 272 degree cams, different exhaust and the carbs, and will likely end up around 160/170 brake.
For sale - E30 320i racer project - sold.
Downgrading an EFI system to Carbs! I've never heard of anything as stupid in my life.
If you really want to get rid of the entire intake system and replace with individual TB's then do so with Megasquirt using alpha-n, but keep the injectors.
You still won't get 45HP extra though.
If you're willing to undertake this cost/complexity then some form of forced induction would be better.
If you really want to get rid of the entire intake system and replace with individual TB's then do so with Megasquirt using alpha-n, but keep the injectors.
You still won't get 45HP extra though.
If you're willing to undertake this cost/complexity then some form of forced induction would be better.
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Brian28
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Some of us are building to race regs, it's not a case of carte blanc doing as we please. If ITBs were allowed then obviously they would be used rather than carbs.gudgeon wrote:Downgrading an EFI system to Carbs! I've never heard of anything as stupid in my life.
If you really want to get rid of the entire intake system and replace with individual TB's then do so with Megasquirt using alpha-n, but keep the injectors.
You still won't get 45HP extra though.
If you're willing to undertake this cost/complexity then some form of forced induction would be better.
For sale - E30 320i racer project - sold.
Well if the race regs require carbs I suppose it's about the best reason going. Do they?
I can't imagine that if EFI is an option it can be bettered by a carburettor though. Only if the EFI intake is in some way limited and this limitation is removed while changing to carbs, but then you could equally just improve the intake and stay with EFI.
But, the OP was asking about individual carbs, my reason for suggesting ITB.
In fact there is an advantage to a well designed inlet manifold and plenum over ITB, I believe it can effectively add a small amount of PSI to gas pressure at intake. ITB is about throttle response isn't it?
I can't imagine that if EFI is an option it can be bettered by a carburettor though. Only if the EFI intake is in some way limited and this limitation is removed while changing to carbs, but then you could equally just improve the intake and stay with EFI.
But, the OP was asking about individual carbs, my reason for suggesting ITB.
In fact there is an advantage to a well designed inlet manifold and plenum over ITB, I believe it can effectively add a small amount of PSI to gas pressure at intake. ITB is about throttle response isn't it?
e21Jason wrote:Apart from poor fuel economy and poor tractabiltiy, and a lighter wallet as you need, manifold, carbs, fuel pump, some why of making the sparks happen.
The gain would be the same as swaping ITB's as all your are doing is reducing the pressure drop across the intake system.
5-10bhp
When I put tripple weber's and a 6 branch manifold on a stock 325i the gain was 8bhp.
I thought a 6 branch alone could give you that (8bhp) if not more!?
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martinpallot
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In conjunction with cams etc. yes, and its only to get more air into the engine thanks to the other mods which make it possible in the first place. A set of webers or bike carbs are pretty useless on their own and all they will do is increase fuel consumption as mentioned before.maxfield wrote:Alot of people go from EFI to carbs with good results (Zetec/Redtops).
As I frequently say on here, if somethings worth doing its worth doing properly. Unfortunately there's no cheap way to tune any normally aspirated engine to a significant level.