g-man
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Registered: 26th Feb 06
Location: East Kilbride
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Opinions please...
A friend has a C16XE that we've had no end of management trouble with. Constant cutting out, over fuelling, shite running etc etc. A carb setup from a X14XE (carbs are jetted for a 1600!) has become available for possible cheap cheap money (sub 500 quid) with everything needed. Carbs, linkage, inlet manifold, fuel lines and small 0.5 bar pump.  
Because of the problems he's had, he's a bit reluctant to fit the carbs and thinks it won't be quick. What do you think? The X14XE was absolutely rapid, and was overfuelling like fuck (because jetted for a 1600). Was never dyno'd but suspect an easy 130@fly. 
Any predictions on power output? My argument is the carbs eliminate the injection system, therefore the cutting out problems too. Also, Lotus had this engine at an alledged 150bhp during development, but it scared the Astra GSi, so they cut the power down to 109 with a crappy inlet!
I say do it! What about you?
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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Add £500 onto that £500 for a ignition ecu and mapping, for a cheap MegaJolt ecu.
Depends how well the carbs are setup tbh, yeah you are eliminating the restrictive c16xe inlet tract, setup well probably see 140ish+ bhp.
[Edited on 27-03-2007 by Vaux Lad]
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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Ignition is run off the standard ECU. £500 for ignition? Noo chance matey. MegaSquirt runs it for half that with hundreds of C16XE maps out there for free
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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How can it run off the std ecu?
The ignition advance curve will be entirely different seeing as you've just junked the entire std inlet system and replaced it with much better flowing intake.
The ecu will have no idea of the amount of incoming air either(junked afm).... Which it uses to set the ignition timing for the precise load etc on the engine.
And the way a carb works, will soon kill the lambda sensor in your exhaust, and your cat if its still fitted.
Yeah, megasquirt can be had for £250, but it will need mapping, anymaps you find ont he net will "work" but certainly not be ideal.
[Edited on 27-03-2007 by Vaux Lad]
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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The standard ECU works because it uses default values and listens to the knock sensor, which will remain.
The MegaSquirt base ignition maps will be fine. The best thing about MegaSquirt is you run about with the laptop plugged in and adjust the ignition to suit.
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Dave A
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Registered: 10th Dec 03
Location: County Durham
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standard ecu wont run with carbs, no matter what bogg bros say
you need to run lumenition or omex ignition system and get it mapped properly to suit, megasquirt and a laptop without the knowledge and a RR is a recipe for det and a big disater.
and it wont run 140 on carbs and a bodged ignition setup, maybe 130 at most.
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joey736
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Registered: 11th Mar 07
Location: hexham, near newcastle drives: Aurora XE
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what if u fitted a vacuum advance/retard dissy from a carb nova or similar, would that work?
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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quote: Originally posted by Dave A
standard ecu wont run with carbs, no matter what bogg bros say
It's been done, and has worked.
quote: you need to run lumenition or omex ignition system and get it mapped properly to suit, megasquirt and a laptop without the knowledge and a RR is a recipe for det and a big disater.
and it wont run 140 on carbs and a bodged ignition setup, maybe 130 at most.
Naturally a mapped ignition setup would be the ideal scenario, but running the standard ignition does and has worked in the past, in the meanwhile.
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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quote: Originally posted by joey736
what if u fitted a vacuum advance/retard dissy from a carb nova or similar, would that work?
In theory, but what would turn the distributor?
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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Carb dizzy is no use as it wont fit the cylinder head/cam.
IMO, it wont work any good on std management. No airflow meter, no TPS, so the ecu can't lookup the map. Probably just be in "limp home" mode.
If it does work, the ignition timing will be completely wrong, and probably hardly see any increase in power.
[Edited on 27-03-2007 by Vaux Lad]
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joey736
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Registered: 11th Mar 07
Location: hexham, near newcastle drives: Aurora XE
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so would a carb dizzy work on an 8v head?
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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Yeah, as 8v's had dizzy's originally.
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Dave A
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Registered: 10th Dec 03
Location: County Durham
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quote: Originally posted by g-man
quote: Originally posted by Dave A
standard ecu wont run with carbs, no matter what bogg bros say
It's been done, and has worked.
how well is the question. I had an Evo4 driving in and out of the workshop the other day with 50% of the sensors and vaccum pipes disconnected. it worked yes, but not very well.
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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I don't see why it's particularly difficult to understand why? It still has the TPS connected, and it still has the knock sensor. Advance and retard can be worked out using 2D quite easily. The knock sensor keeps ping in check. Obviously a 3D ignition map using MAP sensing is the way forward, but the standard ECU is still capable of running it in the interim.
[Edited on 30-03-2007 by g-man]
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Vaux Lad
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Registered: 15th Dec 04
Location: Stoke-on-Trent
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If it were that easy everyone would do that.
It has no AFM, so has no idea about the load on the engine.
The tps will be scrapped with the c16 throttle body, and if you fit one to the carbs it would need be a type that the ecu understands.
Imo, it can't change whether its using a 3d map, or 2d. It will just go into limp home mode, back the ignition timing right off, and probably end up with similar power to a std c16xe.
[Edited on 30-03-2007 by Vaux Lad]
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Warren G
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Registered: 14th May 06
Location: Kent
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run a inlet box off the carbs to the airflow meter - problem solved
and it doesn't matter if there are no injectors connected (or may be connected but doing nothing)
i will work - just not as well as a proper ECU for carbs
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g-man
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Registered: 26th Feb 06
Location: East Kilbride
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quote: If it were that easy everyone would do that.
They do, and have done.
Use the standard TB TPS. These ECUs dont have 'limp home' mode, but will operate as optimal as it can, with what sensor values are available.
I'm not saying the standard ECU is ideal in any way, I'm just saying it won't be as bad as you seem to make out / think it will.
The 1400 running carbs put up a good 1st and 2nd gear fight against a valver.
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