Craigorypeck
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| posted on 7/12/12 at 08:16 PM |
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converting from bike carbs to TBs
considering the upgrade to efi. I'm running bike carbs on my supercharged install, I'm running 2 throttle cables, one for carbs and one
for a throttle body before supercharger. It sounds as simple as just replacing the carbs with TBs with the throttle plates removed? put a tps on the
throttle body before charger.... any issues with bike tbs?
On megajolt BTW and have an injection pump too.. I know sweet FA bout injection so any pointers welcome
Cheers
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mark chandler
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| posted on 7/12/12 at 09:44 PM |
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That's all my DB7 has, large TB in front of the supercharger, then via an intercooler the compresed air goes straight into the engine with
injectors pointing at the back of the valves.
TPS on the tb, air temp and MAP sensor into the inlet manifold.
The supercharger has a second vacumn operated bypass to recirculate the air when you lift on the throttle, bit like a self circulating BOV, it's
has a two way vacumn control on it so when cruising the air bypasses the supercharger so you are not wasting HP compressing for nothing.
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Craigorypeck
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| posted on 7/12/12 at 10:40 PM |
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thats exactly how mine is set up too, has a vacuum operated recirc valve from a mini cooper s, the vac is from after the carb throttle blades, where
have you the vac tapped from? as close to the TB as possible, before charger??
Is a TPS, MAP and air temp all I need to run EFI? and a megasquirt... what about an air flow meter?
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mark chandler
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| posted on 7/12/12 at 11:04 PM |
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Map is all my DB7 has, it's an early, later ones used a MAF for better economy .... Then they went V12 so n/a
My turbo blade only runs MAP as well, so no need to bother with the extra complication.
Remember when you configure the tables you do not need to be linear eg 1000 rpm, 2000 rpm, 3000 rpm etc the same applies to the MAP values in the
fueling table as you group around the most used values, so if you watch the boost gauge it will only dwell in a few areas so group the tables around
these and it will be fine.
The DB7 has all vacumn pipes on the T/B right next to the throttle plate that control the bypass valve, the MAP sensor pipe and air temp are after the
intercooler so measure air that is going directly into the engine so you can leave what you have alone, just drill and tap in an air temp and barbed
pipe (LPG fittings are nice for this) for the MAP output.
Regards Mark
[Edited on 7/12/12 by mark chandler]
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Craigorypeck
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| posted on 7/12/12 at 11:36 PM |
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cheers Mark, I just need some weld in injector bosses and forget about the bike TBs.. and a lot more reading! 
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mark chandler
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| posted on 7/12/12 at 11:54 PM |
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That's what I would be tempted to do with some old pipe as long as you can sort out the fuel rail easily.
Also no need to squirt at the back of the valves, this is for emissions at idle, blasting the fuel into the airflow further back is worth a couple of
HP.
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rusty nuts
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| posted on 8/12/12 at 08:37 AM |
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Have a look at Dave Walkers book on engine management
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umgrybab
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| posted on 8/12/12 at 09:27 PM |
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quote:
Originally posted by Craigorypeck
thats exactly how mine is set up too, has a vacuum operated recirc valve from a mini cooper s, the vac is from after the carb throttle blades, where
have you the vac tapped from? as close to the TB as possible, before charger??
Is a TPS, MAP and air temp all I need to run EFI? and a megasquirt... what about an air flow meter?
I would not think it needed an air flow meter, but I would be surprised if it did not need a coolant temp sensor. Fuelling requirements vary with
engine temp that air temp sensor will not be able to tell you.
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mark chandler
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| posted on 8/12/12 at 11:11 PM |
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Yes, definitely need water temp monitored as well
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Craigorypeck
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| posted on 9/12/12 at 01:19 AM |
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sounds like it should be easy enough, i have most of the basic stuff done on the ignition side of things, megasquirt seams like a decent option.. or
maybe microsquirt?? any favourables? 
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