Lots of things are happening. The engine was mated to its bare 308 gearbox case, for mounting on the dyno, which requires a standard inline, bell housing. In our case, the standard bell housing is from a Buick and requires an adapter plate. We are using a set of dyno headers as they exit in the correct direction. I had hoped to collect some A/F data with my LM-1/aux box system, but the LM-1 has a problem. I need to resolve this for over the road testing. This photo shows the engine mostly installed on the MWE engine dyno. Image Unavailable, Please Login A view from the other side shows the dyno headers, Electromotive ignition system with out spark plug wires installed and the back end of the Superflow (water break) dyno. Image Unavailable, Please Login Changes to the 40DCNF’s, include increasing choke sizes from 32 to 34 mm. Although the carbs have relatively few hours on them, some of the lead plugs show signs of weeping fuel. Anybody have a preferred method to seal them? Anybody know what the Weber bodies are cast (made) of? The plugs are an alloy of lead. The baseline ignition curve starts at 8 BTDC (for easy cranking), ramps to 12 BTDC at 700 rpm, flat to 1100 rpm (for stable idle), then ramps to 35 BTDC at 3500 rpm, after which it remains flat. I’m fabricating a stainless steel sniffer tube assembly for the front bank. Without distributors, I may make some adjustments to the sampling ends for simplicity. Maybe just cap them off with some silicone caps. Does anyone have a mating fitting (6 mm hose barb?) for the OEM, sampling tube ends? The following photos show the newly fabricated sampling tube assembly compared to a new factory part. I have a broken rear bank sampling tube that appears to have some copper in it. I suspect it is Bundy (brake line) tubing but with nickel plating. This picture compares a new OEM front bank sniffer tube assembly above my fabricated assembly made from stainless steel and an aluminum bracket. I/m making is so it can be installed one tube at a time. Instead of brazing the tubes together, I'm going to try and get by with the sampling end clamped in a bracket and maybe a P-clip to constrain the tube bundle near the end of the front exhaust cam. Image Unavailable, Please Login This front view shows the new assembly closely follows the OEM one in shape. The ends need to be shortened but otherwise I think this will work. Image Unavailable, Please Login Bill
I had a very productive trip to my engine builder, MWE, on 7/8/19, to install the ignition system. My XDI-2 system was an early one that needed the later firmware, to use the latest software and be compatible going forward. I flashed the new firmware with great difficulty as the procedure required the pressing of a tiny switch mounted on the edge of the board. It is a known, bad design even when one takes off the end cap with serial connect. While being talked through the procedure by the Electromotive folks, the switch broke apart, apparently a common occurrence. The work around was to short the two solder pad that the switch sat on with a paper clip jumper to be able to scratch through the conformal coating. One has to power cycle the XDI-2 while simultaneously pushing the switch or in my case jumpering the switch contacts with the special tailored paper clip, with bent and sharp ends, kind of like tweezers. Confirmation of success was an observed change in mode on the WinTECH screen. Having previously down loaded the firmware from Electromotive, I now had to flash it using the WinTECH4 software. Mind you, I’m using an old Windows XP laptop, with its docking port, because I need a serial port, not currently available on my new Laptop. Thankfully, this is a onetime event. After flashing the firmware, I programmed and loaded the new ignition curve. Frank was finishing preparations for first start, including throttle hookup, cooling, fuel, and exhaust plumbing, battery charge, and prep the dyno systems. I wired the ignition system, establishing power and running the old plug wires. We were ready to run at about 2 PM. Initial cranking, for about 6-seconds, produced nothing. The key circuit, to the main power relay, was not energized, so no spark. We applied the necessary 12 VDC and the engine started after about 2 seconds, pretty smooth, idle about 1500 rpm. A few minutes of no load operation, varying the rpm, then a series of moderately loaded, short duration runs were made, over various rpm ranges, with recovery gaps in between. Follow on runs were performed at generally increasing rpm and load, as we built up some run time. After about a half hour of running, we did some performance pulls. The attached data sheet shows 331 bhp at 7000 rpm and a torque peak of 248 lbft at 6400 rpm. The engine is basically broken in at this time. A posttest reading of the upstream dyno oil filter, showed a minimal amount of fine swarf or debrit, due to break in wear or residual grit that could not be completely cleaned out. The engine was a bit lean on the high end, so Peter will likely replace the air correctors with ones having smaller holes. We tossed the fan belt (water pump drive) twice and called it a day, after maybe a half hour of running. We used a generic idler pulley assembly in place of an alternator and the best available belt was too big in cross section for the Ferrari pulleys. A new belt was ordered (for dyno use) and should be in. Engine runs were made with dyno headers that look like they came off a formula car, so they are probably much freer flowing than the OEM headers with a muffler. The other difference is the exhaust manifolds are 4 into 1, rather than the OEM 4 into 2 into 1 (tri-Y) which I consider better for street use as the torque range tends to be broader, whereas the 4 into 1 tend to produce peakier but narrower power band. The carbs had no air box or inlet air horns fitted. Peter thinks 350 bhp (3.4 liters) is possible after tuning. That exceeds the magic 100 bhp/liter threshold and exceeds my expectations. We will look at the effects of the OEM induction system. My air box is in very good condition. I’d hate to have to gut it. Maybe trade for a previously butchered one to save this one? My Elan, in similar trim, did 191 bhp (168 lb-ft) with 1.93 liters. Again, no air filters and I think dyno headers. The data shows a torque peak of 254 lb-ft at 6400 rpm, at this time. The engine sounds very smooth, makes some wonderful noises, and starts immediately. I managed to catch the earlier ferry, so was back in Bridgeport at about 6:30 PM. I’ll go back 7/22, to hopefully finish testing. Bill
I forgot to attach the dyno data sheet for the 7/18 test I cited. Note, the computer regulated load is applied after 4000 rpm, at which time the throttles are opened all the way and the dyno controls the such that a 300 rpm/second sweep is performed, up to 7000 rpm, where the run was manually terminated. At this point in time, the engine has been run for less than 30 minutes. Lambda is not recorded, but is displayed on a digital meter, right in front of the operator, Peter. Bill
Wow, I’m well impressed Bill! Didn’t think the 2V would make that bhp/litre. Can you share your carb setup and advance curve as I have a programmable MSD 6AL.
Hi Derek, I will be happy to share setup details when available. An air corrector change (smaller diameter holes for a richer the top end) and revised ignition timing (max advance reduced from 35 BTDC to 32 BTDC, was tested on 7/22. This change increased power to above 350 bhp and increased the torque to over 250 lb-ft, over a range of several thousand rpm. When available, I will plot and post this data. The other thing we quantified were significant losses due to the air box and filter, -30 bhp for the air box and -7 bhp for the K&N filter. I need confirm these numbers. 100 bhp/liter is a pretty good yard stick for a good running, 2 valve, street engine. My Lotus twin cam produced 191 bhp from 1.93 liters, with a similar setup. Image Unavailable, Please Login Bill
Hi derekw, I concur; it is time for a new air box design, as the test data shows the air box assembly has an adverse effect on power and torque. The ignition curve is: RPM BTDC (deg) 400 7 (for easy cranking) 800 12 1200 12 (idle at 1000 +/- 100 rpm) 3500 32 (timing advance comes in fast and peaks early) 9000 32 (all dyno runs presented, used this curve – raw data sheets reflect 30 BTDC, this is incorrect) The DCNF specifications are: 34 mm chokes; 160 mains; 180 air corrector; F-36 emulsion tubes. Idle jet s are unspecified at this time, but probably 57’s. Dyno headers are from a race car and dump into a large tube, with an exhaust fan on the far end. The dyno required an inline mounting. The transaxle case was empty. The following Chart11 compares the torque results of 10 dyno runs. My understanding of the following run cases are as follows. The last run for which I have data, R19 (Run19), is on top of the list. R19 - With air box, without air filter R17 - With air box, without air filter R16 - With air box and air filter R14 - With air horns R13 - With air horns R12 - Air horns added R9 - Bare carbs R8 - Bare carbs R7 - Bare carbs - 180A installed 7/22 7/18 Run - Running lean at high rpm Observations: I was not present for R7 (run7) and later runs. All dyno runs show distortion in the 4000-5500 rpm range. My observations from earlier dyno runs suggests the resulting dip, especially in the torque chart, is a result of the test procedure where the engine is accelerated to about 4000 rpm, the dyno is switched to computer control of load, the throttle is fully opened (WOT) and the dyno controls a 300 rpm/s, sweep rate. This sweep rate is roughly equivalent to what one might see on the road, in maybe third gear, at WOT, so appropriate. My friend Tim, who runs the test lab for an OEM cam drive manufacturer, says they normally use a sweep rate of 100 rpm/s when looking for component resonances. This slower rate allows component members time to display their natural frequencies and determine if there is a noise, displacement, or durability problem, a different requirement than ours. R7-R9 appears to be the same test case, based upon the dyno sheet notes. The data shows they tracked each other very closely on the power chart. The torque chart shows a pronounced dip in 4500-5500 rpm range, but good overall correlation to each other. I believe this is a result of the test procedure and interaction of the dyno system. R12-R14 appears to be a single test case with OE air horns fitted. I do not know if the base of the air box was fitted. I do note that R12 is noticeably lower on the torque chart in the 6800-7500 rpm range than R13 and R14. R16 was fitted with the OE air box assembly and air horns, a used washable filter and the OE top cover. The vapor containment, flap assembly was wired in the open position. The air box housing is not original to the car but is believe to be what was originally fitted. There is noise insulation in the nose, retained by a steel mesh fence. This treatment is limited to the snorkel and its transition to the air box cavity. R17-R18 appears to be the same case. They differ from R16 in that the air flier element is removed, but the box is still fitted with the OE air horns. The OE air box and filter assembly cost about 30 bhp at 7500 rpm and 10-15 lbft at about 6300 rpm. Did we ever look at the case of the air box assembly with and without filter fitted, but no air horns? I’m thinking shortie air horns and a remote filter as being the basis of a custom high flow system. Do the air horns hinder or hurt performance inside an OE filter and housing assembly, on my engine? The data shows R16 power peaks out at about 7400 rpm. Removal of the air filter for R17 and R18 shows slightly higher (about 5 hp) levels over about 5400 rpms. This appears to mean the air filter restriction is important, but not as important as the overall air box housing and likely the interaction between the air horns and underside of the air box cover. Available rear deck height is limited in this area. Later cars may have some lessons to teach. My chart11 compares corrected power results for 10 dyno runs. Image Unavailable, Please Login Chart 10 compares torque results for the same test cases. Image Unavailable, Please Login Test case 16 is the closest we came to the probable,on car configuration. The preceding data was smoothed using a moving 3 point average to minimize scatter.Raw data points for Run16 (R16),are compared to their 3 point moving average. Note the data dip between 4800-5700 rpm. This dip coincides with engagement of the automatic sweep mode of the dyno. The dyno is transitioning from manual control, to computer control of the load, to yield a sweep rate of 300 rpm/s, at wide open throttle (WOT), a fairly brisk rate. Chart16 below, shows data from R16. This case is as close to a road configuration as we got. Out of the box, this is about what I expect on the road. Image Unavailable, Please Login Bill
