After opinions please :)

[Big Vern 89]

Hi folks, 

Im just wondering on any opinions of a conversion to fuel injection. This place is near me. No Esprits on there but i think there is an Excel. Anyway have a look and let me know what you think.

TIA

Brett 

https://www.classicfuelinjection.co.uk

[snowrx 77]

It appears the DCOE throttle body they offer does not have the same inlet flange as our Dellortos (or DCOE's for that matter) to accommodate the air box. Looks like you'd have to go from a hose coupling to some sort of airbox adapter. Some thing to plan around. 

It's not clear if this will support a distributor-less ignition (coil per plug), which was a consideration for me as I wanted to get the rid of distributor & HT leads under the fuel system, which to me is an invitation to an engine  fire.

A basic system, not many bells and whistles, all your support will presumably be through the vendor, versus the forums that support more widely fitted ECU's

[lotus-62 27]

I got myself some 45mm jenvey throttle bodies (a lot cheaper than what I have seen on  the "classicfuelinjection" site.)  and an EMS fuel injection ecu.  but many universal sets are available (even diy sets like megasquirt or KDFI , VEMS)  I paid for the ecu/throttle bodies/coil/fuel pump and some used injector around 1000euro.  I love the fact that the leaking carbs do not sit above the distributor anymore (both are gone)  plus the spark timing is way better controlled compared with the old sytem.  can't wait to finnish the europa so I can start with the fuel injection on the esprit. 

btw  go to the megasquirt forum  you learn so much about EFI so you can pick the correct system for your needs.    

[jonwat 262]

Can you not bolt the throttle bodies direct to the head?

The problem using the carb manifold is the 45 degree bend will restrict airflow, the later FI cars had a shorter, straight manifold as it no longer needed to support the horizontal carbs. 

[drdoom 169]

I would disagree on Jon's points, the later, FI cars may have had a shorter manifold in terms of where the throttles are carried but the IR tracts were lengthened substantially with the pieces that complete the inlet. I believe this inlet type did, in fact, turn the tract from 45 degrees (normal to the port face) to horizontal. While it likely matters at the F1 level, is there basis for the assertion that the bend will restrict airflow in this instance? Direct to head throttle  bodies are bespoke, of necessity, owing to the distinct spacing dimensions of ports, one engine to the next. Owners of Vauxhall XE powered cars have that option, perhaps some Honda or Ford as well, but DTH items haven't been offered  for Lotus in my experience.

From what I see, Jenvey seem to offer quality pieces and sound technical advice as well. Worth a look.  

[snowrx 77]

Much prefer the Jenvey's as they will let you bolt up your existing airbox. Although they will still have issues with wetting the port walls rather than a more direct shot at the intake valves. For what it's worth, I went with a DIY Megasquirt on my turbo-

https://www.lotustalk.com/forums/f164/910-megasquirt-339834/

[lotus-62 27]

don't go for direct on the head. it shortens the inlet lenght way to much so you loose instead of win. keep the lenght the same and you are safe.  I like the bend instead of a straight fit (but same lenght)  the injector is at an angle and because of that bend it does not hit the wall direct but points straight at the head and has a bit more time to mix with the in comming air.  I don't know if the port in the head bends perfect so the injector sprays at the valve, with an injector that has a narrow spray pattern you feed both valves without wetting the walls too much.  short inlet is nice for high revs but I drive on the road so mid range is what counts for me.  

one of the first guys that did this on his s3  made his own throttle bodies from old dellorto's but they where too short and he directly noticed it, extended back to the dellorto lenght and all was fine.  (still not enough BHP I think because later he put an audi v8 in it) 

and yes, I like the jenvey's  as the same bolt pattern let me put the air box back in the org. place   there are throttle bodies around that look like dellorto/weber carbs and have the injectors inside.  

 

Edited October 11 by lotus-62

[snowrx 77]

Something to keep in mind at this point is how you will plumb in an idle control valve with equal distribution to the 4 ports, should you wish to have electronic idle control. Drilled DCOE patterned spacers, or some hose barbs, or perhaps your manifold already has some provision. Same concerns and plumbing for a vacuum source if you're not going to go to an electric pump.

[jep 191]

LotusBits have certainly done fuel injected Excels before...with great success I am told. I would chat to them first as they have years of experience with the 900 series engines.

Justin 

[jonwat 262]

I was basing my comments on my understanding of the physics that a 90 degree bend reduces air flow by 50%.

Also, I'd gas flow the head & manifold, removing aluminium in order to match up the two & maximise air flow.☺

Edited October 12 by jonwat

[lotus-62 27]

I have been thinking about vacuum for engine load (MAP/alpha-N ) but as the car is for the road I think a MAF/hot wire will be better, plumbed somewhere in the inlet before the filter box,  so I just end up with vacuum for the brakes.  did you do Alpha-N and how does it drive?   

 

[snowrx 77]

I went Speed-Density (RPM/MAP) on mine with a single throttle body as that's what I had available, and I wanted to delete my vacuum pump. The common plenum gives more usable vacuum, and I could use an OEM throttle body with integrated idle air control . Common wisdom is that this gives up some throttle response compared to individual throttles.

With the individual throttle bodies (per-port) I've heard Alpha-N is easier to set up due to the pressure pluses in the ports and quick drop off in MAP as the throttles open. Some have used four hoses to a common MAP sensor, or electronic combination of signals from 4 MAP sensors trying to get representative MAP load signal with ITB's, but I have no experience with that or MAF setups.

[Laika 70]

With injection dont you also need to replace the pump, add a swirl pot, add a fuel regulator and a return to tank ?

[andydclements 488 2 Vehicles]

What is the aim of going FI?

If it's reliability, tractability , easy starting etc then that seems like a good idea but don't expect to get a massive power increase as the 45s deliver pretty much enough fuel as the standard engine can handle, more power will need the adjustments that @jonwat called out.

[lotus-62 27]

snowrx thanks, I've heard vacuum is very low on 4 throttle bodies.  some put 4 in 1 with a small damper before the sensor.  Alpha-N only needs barometric correction with an sensor in open air.  some will do a hybride of Alpha-N with speed density part throttle.    I want to see what MAF will bring...  just a testing/learn curve.

 Andy, yes FI is not for more BHP,  BUT it gives the points you mentioned above plus I like the fact that the leaking carbs on top of the dizy are gone (and the dizy itself)  plus my carbs are in a very poor state so why put a lot of money in them for a rebuild/tune .  engine will response better as well because the spark timing is more accurate and better to program.    

laika, I need a new pump and new fuel lines  anyway.  a fuel regulator is at the end of the fuel rail and a single return to the tank.  thinking about a intank fuel pump with a semi swirlpot inside.( a folded sheet metal spiral around the pump so in a hard corner and low on gas the pump will not suck air.   did this on the europa and seems to work well. 

I only see good points with FI 

[drdoom 169]

Agree with points made by Rick and Thomas, though without experience in this I have been researching the heck out of it for years. Distributors are problematic in terms of replacement rotors, caps etc. being of suspect quality from time to time. I was busted down for days in a small Oregon town enroute to California with my Elan until able to sort out a dielectric failure in the rotor. The burn-through was all but invisible to the eye and it failed quite some miles into service. I'll be pleased to go with modern ignition in the S2 when finishing the restoration, noting how difficult the distributor location makes things when tuning and servicing.

Quite right that vacuum signals are not particularly useful in independent runner (IR) set-ups, which Lotus always rightly preferred for N/A engines from the Elan DCOE's through the Dellorto's on later cars. Turbo's are more well served via a plenum intake and single throttle body, making good use of the vacuum that affords with a MAP sensor and augmenting that with MAF. So my choice for Vern's car would be EFI with IR throttles with a top spec TPS, distributor-less ignition and the lot mapped via Alpha-N inputs. I suspect one would manage life without idle air control (IAC), the ECU supporting cold start and running by way of temperature based corrections to fuel and spark.

[snowrx 77]

5 hours ago, Laika said:

With injection dont you also need to replace the pump, add a swirl pot, add a fuel regulator and a return to tank ?

On my street car I skipped the swirl pot, given the relatively tall tanks on the Esprit and the fact the OEM fuel sump is the very lowest point in the system, and kind of a little pot anyway.  If I were to run low on fuel in a sustained left turn I suppose I'd eventually suck some air, after looking at the low fuel light flashing for a while.  I'd rather keep the tanks full than find room for more plumbing & pumps.   If it were a track car I'd look at adding a swirl pot.

[Bazza 907 772]

You're car to with what you want etc etc but as you're asking for opinions, personally I'd leave it as it is. Nothing wrong with it being as it came out of the factory and of course if you ever did sell it I suspect the next purchaser would prefer it stock. Appreciate that you could reverse any changes but is that likely?

Just my 2p worth

[Big Vern 89]

Thanks guys, most of that goes over my head, my initial thoughts were from the safety aspect of not having the carbs over the dizzy cap etc. Also from a reliability point of view too. I suspect even this would have its issues then. Thanks for your thoughts though, it is something to think about. Regards to all :)