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Re: EFI solutions and comments

PostPosted: Thu Feb 20, 2020 6:49 pm
by elanman999
Hal,
I used the standard S4 air box and trunking. I used Jenvey trumpets but I had to turn the O/D down to make the fit.
I'll post some pic tomorrow, too cold to go out in the shed now. LoL.

Sprintsoft, EFI will give no more BHP than a well setup pair of Webers, but it will give you more torque, better fuel consumption and driveablity. Also less maintenance required as no points to adjust, and plugs are less prone to foul up. Yes it is a lot of cash but if you drive your car alot it's worth it.
YMMV.
Cheers
John

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 12:21 am
by sprintsoft
Thanks John, very interesting...

Does anyone know the typical advance curve used by these ECU’s? Do they aim to emulate a 23D4 distributor for instance, or they take a different approach?

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 9:55 am
by elanman999
Hal,
A couple of pics. I'm not sure if Jenvey still sell the same trumpets that I have but they look like the AH45*40. I have trimmed them to make them fit in the air box back plate.

Sprintsoft, The big change, advantage, with the mapped ignition is that you have an engine load input and so what happens on full load is very different from off load. I'll see if I can get a screen dump of my ign curve.

DSC02811rs.jpg and

DSC02814rs.jpg and

Cheers
John

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 10:56 am
by elanman999
Sprintsoft,
Just thought, you down load the Emerald software from their site. PM me you email add then I'll send you my full map.
Cheers
John

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 11:51 am
by Andy8421
If it is of any help, there is a guy on eBay who manufacturers deep airboxes.

https://www.ebay.co.uk/itm/Lotus-Elan-2 ... Sw8LNeSw9S

I have not bought one from him, but he advertises both Sprint/S4 and Plus2 boxes, although the Sprint box isn't currently on eBay - he may be worth contacting to see if he has any available. I believe TTR also supply them.

There have been threads about the critical nature of the trumpet to airbox clearance required, and the belief that the standard box has insufficient clearance for the rear trumpet. Airflow into a one choke per cylinder trumpet is a highly complex standing wave, and isn't the simple flow that you may imagine - though it probably only matters if you want to get the very last HP out of the engine.

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 1:35 pm
by elanman999
Andy,
Thanks for the link.
Personally, I am a bit sceptical of the need for a wide air box at the power levels I am talking about. Sub 150hp that is. I believe that your last comment is true.
The minor problem with the Jenvey trumpets is the diameter, they foul of the front cover fixings.

I would also remind you that the early +2's had an even narrower air box, now that may be a little too narrow. But the first road test of a +2 by Motor magazine in Sept 67 of the now infamous LPW120E was timed at MIRA with a mean top speed of 122.5 MPH. So there cannot be too much disadvantage in the narrow air box.
Cheers
John

Re: EFI solutions and comments

PostPosted: Fri Feb 21, 2020 2:54 pm
by Rob_LaMoreaux
I just saw this thread and have found it interesting since I have been thinking about going to EFI someday. My plan would be to find some used motorcycle throttle bodies, mass air flow, and use an ECU from work since we still make those even though most of my projects lately are EVs.

As for speed density versus MAP, most engines today use both but base a lot of the strategy on MAF. Using a blended strategy with UEGO feedback gives excellent drivability, economy and performance. MAF has a lot of advantages for steady state and most MAF sensors today also have intake temp, barometric pressure and humidity allowing compensation for environmental conditions. In addition a MAF sensor would be an easy addition to the trunking from the plenum to the air filter on a stock Elan. For transients the TPS and MAP provide a bit of look ahead to make up for the delay from the MAF sensor to the intake valve.

This is why EFI. The system can adapt and adjust to provide proper fueling in all conditions so you don't get stumble during transients, the fuel economy and power output are optimum and things don't go out of tune. No it won't start when the temperature changes or the points wear out (Ignitor does take care of that with carbs). On the other hand it is not cheap and getting the tune perfect can take a lot of dyno time (less with a good adaptive strategy).

I'm surprised at the complexity of the fuel pumps, but then most of what I have done was early low pressure systems and modern high pressure DI return-less systems. I would think the TwinCam would be close to the low pressure system on the 1990 Alfa with Bosch Motronic my wife had, and I do not think it had a return. I'll have to look into it some.

Then again with no electronics the TwinCam has less to mysteriously go wrong...
Rob
Of course for me it is all a thought experiment for now since my kids have expensive activities and the Elan restoration is 20 now so I need to look into things like the rubber donuts and brakes before I start upgrading too much. Though I may get the UEGO this year and try to improve the Weber tune so they don't run soo rich.

Re: EFI solutions and comments

PostPosted: Sat Feb 22, 2020 10:32 am
by gav
On the air box point, I ended up with narrower throttle bodies which gave more space and a Tony Thompson air box which is similar to the one on ebay but has a deeper base.
It was very expensive and not particularly well made for the price. It does fit extendable trumpets but the don't extend too far because of the box depth.
I agree that the longer the trumpets, the better the control
I was thinking about Spyder's version for the next try.
Photos of my install earlier in the thread.
Gavin

Re: EFI solutions and comments

PostPosted: Sat Feb 22, 2020 10:53 am
by JonB
elanman999 wrote:Andy,
..the first road test of a +2 by Motor magazine in Sept 67 of the now infamous LPW120E was timed at MIRA with a mean top speed of 122.5 MPH..


Was it infamous because the bonnet catches were "broken"? I couldn't imagine driving that fast in mine (which is an S130 Big Valve).

Re: EFI solutions and comments

PostPosted: Sat Feb 22, 2020 11:07 am
by HCA
John - thanks for the photos! I immediately see though that the Plus 2 is quite different to the Baby Elan. I did not fully realise this until I saw your photos. Your airbox is above the master cylinders, whereas the Plus2 it is on the same level, so no matter what, I will never be able to fit longer trumpets. You could, on the other hand, fit much longer horns if you were happy to modify the depth of the airbox.

If only the designers had used a cable operated clutch, I'd be OK for 90mm horns :lol: :lol:

Andy, thanks for the link and your comments about the clearance needed for the trumpets to be efficient.

I do confess that I was sceptical when I first opened the airbox that 3 and 4 had very little room to get a full friction free air path, but know very little about airflow mechanics to comment.

Do you have any links where the subject is discussed in layman terms maybe?

Re: EFI solutions and comments

PostPosted: Sat Feb 22, 2020 4:39 pm
by prezoom
In dyno testing, we found the minimum distance from the end of the air horn to the edge of the air box, was one and one half the diameter of the carb intake diameter. In other words, if you have a 40mm carb, the distance should be not less than 60mm. On both the Elan and Plus2, with the original twin cam, the rear section of the air box does not meet this measurement. There is room on both designs to increase the distance with a modified air box.

Re: EFI solutions and comments

PostPosted: Wed Feb 26, 2020 8:11 am
by stugilmour
Following up with additional information on the Aeromotive Phantom Stealth 200 in-tank pump kit mentioned above.

Kyle pointed out the bladder/baffle has four openings to the main tank, but they have no effective check valves to retain a high fuel level at pump suction. I found Aeromotive Bladder Baffles SKU 18020, which are small check valves that can be fitted into the existing holes. They should probably be included in the basic kit.

https://aeromotiveinc.com/product/phant ... 6+18689%29

Was able to examine a kit locally. The bladder and foam are ~7” diameter and ~12” tall. The kit is specified to a 11” max tank depth (1” of foam compression to hold everything in place). If required, I found Phantom Extension kit SKU 18788 that will accommodate a tank depth of up to 22”. I would hope the basic kit could be fitted/fettled into the ~12” high Plus 2 tank, but just in case it is good to know there is a designed solution.

https://aeromotiveinc.com/product/phant ... nsion-kit/

My Axminster tank is in the car, so measurements are approximate. Tank is 25” wide, 14” front to back, and 12” high. The tank floor slopes upward 2” toward the front, leaving about 6” of flat floor at the rear. Fuel level sender centred on back wall. The right side filler is located toward the rear of the tank. This leaves the right rear as the most promising spot for the unit. My 1” wide hold down strap is presently ~2” in from the right wall, so that may need to be moved slightly to avoid the pump outlet cap and gasket.

Andy at Axminster Tanks got back. Said there are internal bracing and baffles that will have to be avoided. Although he said the weld locations should be visible on the outside walls, they seem to be pretty subtle. I think I see bracing located 8” in from each side, but the sender will have to be removed to check visually. Probably smart to do this prior to buying a kit. :D To be honest, Andy was not that keen on the Phantom kit, so there is that to consider.

Assuming there is 8” open at the right rear of the tank, I think the 7” diameter kit should fit. The foam and bladder should be flexible enough to deal with a few inches of sloping floor toward the front of the bladder. I would try to clock the bladder to locate the four fuel entrance holes clear of the tank walls, any bracing, and the sloped floor. The top mounting cap should be about 4” to 4 1/2” diameter (should have measured it) in order to cover the 3 1/2” hole in to the tank, so I expect the hold down strap scooted over an inch should work? The stereo speaker is very close as well. Cap would be clocked to take the fuel hoses to the left. There is just enough clearance below the valence panel for the mounting cap and AN-06 hose, but not for a fuel filter.

Plenty of room under the fuel filler for a filter, regulator, etc. if desired. Would use AN-06 hose over to the centre of the boot front bulkhead. The Spyder chassis has provision for 3/8” hard tubing on the top of the tunnel. Thinking AN-06 bulkhead fittings could attach to the tubing, which could be fitted between the body and the frame below the fuel tank. My engine and transmission are out right now, so hoping the lines would slip in from the front.

Have attached a few pics I found on the forum that have been a big help.

Next topic I am examining is locating the pressure regulator. I am hoping to use Jenvey Heritage TB’s, so the fuel rails inside each TB are effectively deadheaded. I would like to mount the full return regulator in the boot and run a single high pressure fuel supply line forward to a conventional tee style fuel loom. This saves fussing how to bring a return line over the bell housing. I see sone folks have done their installs this way, rather than locating the regulator somewhere under the TB’s. Given the difficulty installing lines with the drivetrain in place, I will probably run both tubing runs now in case the deadhead setup doesn’t work too well. Any thoughts welcome.

Stu

Re: EFI solutions and comments

PostPosted: Wed Feb 26, 2020 4:06 pm
by disquek
Those check balls are a great find. It looks like the larger side might need to be on the inside of the accumulator. Make sure there is room.

This came today. Not very "Lotus-ish". The other side of the same coin.

-Kyle

Pp0rmBfnRBCVKTMHCOsBzA.jpg and

Re: EFI solutions and comments

PostPosted: Wed Feb 26, 2020 11:57 pm
by stugilmour
Good eye Kyle. Yes, I believe they are mounted externally. If you order for your Mustang could you post pics/dimensions? Note they have different P/N SKU’s depending on how many are needed for your application, but I understand the actual valves are the same size.

Cool kit for the Mustang! Are you going a Holley setup?

Stu

Re: EFI solutions and comments

PostPosted: Thu Feb 27, 2020 3:17 am
by disquek
Edelbrock Pro Flo 4.

This looks neat. Might even work in the tank kit I got for the Mustang.
https://aeromotiveinc.com/product/baffl ... m-200-340/

-Kyle