Please keep it simple as I don't want my brain imploding.

Let's say you have a v4 carb fuel engine, what it the minimum parts to change to fuel injection. There is a signal when cylinder 1 fires (wasted spark) . There is an ecu that controls the spark. G
My list is as below.

= throttle bodies
= inlet manifold pressure sensor
= inlet air temperature sensor
= control unit e.g megasquirt or speedunio

Using maf and ignition signal, the rpm can be calculated so the timing for the cylinders (uneven times as its v4) can be derived and maf on cylinder 1 would identify which of the two cylinder 1 sparks occur on the power stroke.

Obviously the ecu needs to be programmed for this.

Fuelling is guesswork unless an oxygen sensor is fitted to the exhaust.

Is that it or anything else needed?

high pressure fuel pump, regulator, and return

^^^^ Yes, And
= throttle position sensor (TPS) that should be on the TB.
= inlet manifold plus linkage for the 2 pairs of TB... Actually if the outer diameter of the TB is the same as the carbs, then the TBs fit using the same rubbers.

[Edited on 13/11/20 by 02GF74]

An Engine

An Engine

Two engines, yer having a laugh.

I'd definitely fit a oxygen sensor if you want to do it right. I also like those dash displays that show you the fuel air mixture with a lambda sensor, I was thinking of fitting one to my cars exhaust so I can keep an eye on the carbs state of tune.

well, its a v6, so two posts equels two engines !

I dont know who this site posts twice,

steve

It's a v4; two engines make it a v8.

Could the map (manifold air pressure) sensor be eliminated?

During cranking, the controller selects one of the two ignition events to squirt fuel. If after a few cycles revs don't pick up, because engine is not firing, it then selects the other ignition event to squirt fuel.

Obviously having unburnt fuel in the exhaust will create a back fire so to limit this only squirt into one or two cylinders? The engine should run on 2, maybe even one cylinder - after long periods of non use, I'd get my crossflow running by removing 2 plugs to make it easier to spin on the starter and it ran quite smoothly on just 2 cylinders.

Re oxygen sensor, would instead having an air mass sensor on linlet be enough, knowing mass of air going in, the controller could calculate the amount of fuel to give the correct ratio - would an air temperature sensor be required as well?

Injectors might help..

Is it a Car or Bike V4

I converted a Carb'd Suzuki RF900 to Megasquirt.
I used the bike's Ignition, the coil drive for a crank sensor.
megasquirt V2 (8 bit one) had a MAP sensor on the PCB.
MAP did not perform well at all, as the bike engine flowed so well the MAP vs TPS was very uneven.
Megasquit with the "Extra" coding offered a Hybrid version thyat mixed TPS and MAP. Work Well.

Bits I Used were....
Bikes Spark uint. (wasted spark)
Suzuki GSXR600 K1/2 throttle bodies.
2 diodes for the coil drive Megasquirt input
GSXR/Bandit fuel pump fitted to a small header tank. this has an intergrated regulator.
MegaSquirt one version V2.2 with MSExtra code.
Cheap narrow band O2 sensor , later a Wide band with monitor.

Just a note. Megasquit offered MAP/TPS or TPS/RPM for fueling and MSextra also gave the Hybrid version as well.
I think Megasquit version 1 V2.2 can do sparks ,but with limits.

motorcycle V4 - thought I mentioned it but I see I have not

Incidentally are the any bike TB that are all separate so can be respaced - I'm looking at GSXR 750 and 1000 that appear to be two pairs. Need to be able to supply a 160 bhp engine.

quote:

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Originally posted by 02GF74
motorcycle V4 - thought I mentioned it but I see I have not

Incidentally are the any bike TB that are all separate so can be respaced - I'm looking at GSXR 750 and 1000 that appear to be two pairs. Need to be able to supply a 160 bhp engine.

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GSXR600 K1/K2 Are separate
I think they are 38mm
The worked well on my RF900, I guess 110-120 bhp

V4 does the VR800 have fuel injection.

What V4 bike

VF ,VFR , V MAX are the only one I know of.

Thanks for that, I was looking at gsxr 750 /1000 on that well known auction site without success, it seems K2 is the magic word that shows separate bodies.

There's a few more, some Ducati and Aprilla but in this particular discussion its Vmax.

... and for those that did a straight swap from carbs (twin weber/dellorto) to fuel injection, what was the power gained?

When I injected my 893cc carb fireblade engine so I could add a turbo, this was years ago!

Megasquirt 1. With ‘Dave’ resistor and picked up engine running/rpm from the bikes spark ECU

The injection was batched so did not care about crank position.

Fitted throttle bodies off a 954 blade engine, the spacing was all wrong and these are fixed TB’s that do not split so made a manifold to match, this was cranked to keep everything low.

The megasquirt had a MAP sensor on-board, TPS came with the throttle bodies so just added engine temp and air temp.

It ran brilliantly, 201bhp on the rollers @ 0.8 bar boost.


plenum 1

[Edited on 15/11/20 by mark chandler]