Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: Pfreen on Saturday,August 18, 2018, 07:27:50 AM
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Attached are the chassis dyno results for my Lotus Europa Special. It has a five speed 365 transaxle. The engine has been blueprinted, balanced, cc'd, compression ratio raised to 10.3:1, extensive porting, headers, standard size big vales, and it has a Dave Bean sprint cam. It also has two Hitachi SU carbs (Stromberg head). The ignition system is an Electromotive HPV-1. The advance curve is set as a straight line interpolation of between 1000 RPM, 3000 RPM, and 7000 RPM. The 98 BHP run was in third gear and all the other runs are in 4th gear. Since the air fuel ratio was fairly at high load, I leaned the carbs out by screwing the jets, which gave the highest 115 BHP reading. However, it would not idle at this setting so I richened it up a little. I then advance the timing 3 degrees (every reading advanced from what is in the graph). This did not measurable change any torque reading throughout the RPM range. From this, I believe the timing curve is fairly close to ideal.
The timing curve shows what I dialed in and all the curves in Miles Wilkins book. If indeed anyone set their timing as shown in 41225A Stromberg, the timing would be very retarded.
I have now installed an oxygen sensor in the exhaust to monitor the air fuel ratio and dial in the carb needles so it does not go so lean at low load and so rich at high load.
I hope others post their dyno results. There are very few results posted online.
Enjoy!
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Thanks for posting your dyno results. I'm wondering what an optimized stock Stromberg setup would produce.
Joji Tokumoto
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I love looking at dyno curves. It pulls really good up top. "Most" cars fall off by 6500. Your afr is good for turbo but killing your hp and torque, especially down low where you need it most. When you get your needles dialed in it will be really screaming.
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I don't have a Twin Cam and I don't have a fancy computer plotted dyno sheet but for those who are interested, here is the dyno sheets Dave Bean drew up for me when he built my motor back in the old days of pen and paper (1981).
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So what engine is it BDA? Stock, modified, engine dyno?
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Yes, it's a BDA, it has a warm cam, it's been balanced, blueprinted, ported, etc. and yes, the dyno run was an engine dyno - so it's not a direct comparison to your dyno results.
Dave said, and it's pretty obvious from the graph, that there's more power above 7500 rpm, but because I opted for a cast crank, 7500 is my red line. Dave offered a steel crank for $500 and unfortunately I demurred, but on the other hand, I figured I didn't really need to go above 7500 on a street car and at another 10% more for the motor it seemed pretty expensive.
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Remember, you are comparing apples and oranges. Pfreen is using a rolling road dyno and Bean an engine brake dyno -- nevermind differences in altitude, humidity, temp, etc. 115 hp at the rear wheels is pretty fine. Typically wheel HP is 15% less than engine hp. That would give Mr. Pfreen roughly 132 hp at the flywheel. Do even better if you binned those SU clones and fit modern motorcycle carbs.
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I have been trying to document the horsepower changes in my Early Twin Cam Special. An optimized Fed Spec Big Valve gets about 83 horsepower at the rear wheels and about 97-98 horsepower at the flywheel. My plan is to keep it as stock looking as possible but to maximize the stromberg setup with the factory airbox. My TCS already had the emissions removed when I got it. I wanted to document the horsepower changes on a dyno after each change to see how much of an increase each mod did. The first change I did was switch to a Borla high performance exhaust. The car dynoed about 89-90 horsepower at the wheels which seemed about right for a 46 year old motor. I switched to electronic ignition (Pertronix Ignitor III and Flame thrower III coil. This surprisingly added about six horsepower on my next Dyno run. The next change was to add headers (from R&D mild steel). I was hoping for more but the headers only added three horsepower. My last run showed 99 horsepower. All dyno runs were done at the same place and approximately same time of day (10 a.m.). I just had the Strombergs rebuilt and the needles switched out to B1DTs and the cams reground to a slightly hotter than factory "E" spec. My car had the original Federal "C" spec cams. I am hoping to get another 10 hp on my next dyno run.
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Here is the first dyno run.
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That's a much better way of evaluating things, good work. Fitting modern flat-slide, smooth-bore motorcycle carbs will make a huge difference. It wouldn't look that out-of-place either.
Spot on about the headers. Hard to beat a nice 4-2 manifold for the street. Mostly headers are just noisier and more fragile.
Did you change the ignition settings when you switched to electronic? Bigger plug gap even? As long as it wasn't missing, it shouldn't make that big a difference.
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What needles are you using? I'm thinking of switching to SU's for my 73 TCS.
Sherman
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The carbs are four screw round top Hitachi SU’s off of an early Datsun 240z. They came with the car when I bought it in 1986. The needles are SU SM. I just had the throttle shafts rebushed by Z therapy in Oregon. They have been very reliable and the car runs great. I did not even realize it ran rich at full load.
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Better that than lean.
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Thanks. There is an article on switching from strombergs to SU's and in the article it suggest OA8 for the needles. It looks like when I'm ready I may have some experimenting to do.
Sherman
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Where did you find the article?
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http://www.lotuseuropa.org/images/WorkshopManual/Carb1.pdf
http://www.lotuseuropa.org/images/WorkshopManual/Carb2.pdf
http://www.lotuseuropa.org/images/WorkshopManual/Carb3.pdf
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Fitting modern flat-slide, smooth-bore motorcycle carbs will make a huge difference. It wouldn't look that out-of-place either.
Bike carbs are an intriguing idea. Am I right that retrofitting a Stromberg manifold car with 2 bike carbs would require something like carbs designed for a 1600cc V-twin? These for instance?
https://www.maxairengineering.com/mm5/merchant.mvc?Screen=PROD&Store_Code=ME&Product_Code=MAX_HSR_42&Category_Code=ROADSTAR
I'd be interested to hear if anyone has tried this and what the benefits and pitfalls are. Seems like a more reliable solution than those godawful Strombergs.
Tom
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There is nothing wrong with the Strombergs except they wear and were set-up to solve pollution issues not to perform. You can set them up to run well and reliably — I posted a long article on this previously.
However, all that said, they are still restrictive while modern bike carbs are not. There is literally no restriction at WOT. Weber’s/Dells still have lots in the way at WOT.
I would size the carbs based on the intake bore. Probably 45mm carbs would fit the bill.
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I found the articles on this forum ;D
It is 3 pages, here are the links:
http://www.lotuseuropa.org/images/WorkshopManual/Carb1.pdf
http://www.lotuseuropa.org/images/WorkshopManual/Carb2.pdf
http://www.lotuseuropa.org/images/WorkshopManual/Carb3.pdf
Sherman
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I just ordered the OA7 and OA8 needles from Joe Curto. I’ll post the results.
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For what it's worth, a lot of guys on the lotuselan.net site have dyno'ed their twin cams. Most say on that forum that the 126 hp sprint spec cars dyno out at the rear wheels between 90-100 hp. One guy on this forum a few years back dyno'ed his slightly built TC engine at the crank at 135 hp and 103 hp at the rear wheels. That would make "pfreen's" 115 rwhp translate to more like 145+ hp at the crank or at the very least 140+hp which quite impressive for a Stromberg head. I've see his car in person and his TC is quite impressive. I can't wait to get my to get my TC back next week from Twin Cam Racing in Sarasota to see how much of a difference the reground cams and B1TD needles translate on the dyno.
PS I really wish a lot more guys on this forum would dyno their Europas just to compare notes. To me it was $50 dollars well spent to see what actual differences all those slight changes make to my Europa.
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So I bought the OA7 and OA8 needles from Joe Curto. The OA7 was way too rich. The OA8 leaned out cruise at 50-80 mph to about 14.7:1 from 13.2-13.5 with the SM needles. It runs great, so I am keeping the OA8 needles. At wot, it goes rich to about 11.5 To 12:1. That could be due to the needles or the dashpot enrichment. I am using 3 in 1 oil (not the 20wt) in the dashpots. It really improved response from 20 wt oil I was using before. I also bought two colortune plugs to set/insure the carbs were set equally for a/f ratio. I have a Unisyn so I made sure the throttles were synchronized.
The change in needles should improve my mileage and the plugs look great. I am running Champion n7yc and am very happy with them. I tried ngk iridium plugs but I found they fouled easily. They may be fine now since the engine is broken in and the carbs set up.
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It sounds like you have things worked pretty well. :beerchug:
I would suggest that instead of a Unisyn, that you get a synchrometer (https://www.ebay.com/itm/VW-Porsche-Dual-Carburetor-Synchronizer-Synchrometer-Airflow-Meter-Weber/172304682623?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649). I have a Unisyn and the synchrometer was much easier to use and much more accurate.
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Sounds much better. WOT and low 12s is just fine.
I use dexron 3 automatic transmission fluid in SU and Strombergs. It’s lighter than 20 weight and, bonus, doesn’t swell diaphragms.
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I don’t recommend 3:1 oil. It turns hygroscopic if heated.
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Just dynoed the car with the reground cams. 108 rwhp and 102 torque from Stromberg head and carbs (B1DT needles) normal compression 9.5:1. Had the rev limiter set to 6200, so it looks like it might have gotten a few more hp.
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Just dynoed the car with the reground cams. 108 rwhp and 102 torque from Stromberg head and carbs (B1DT needles) normal compression 9.5:1. Had the rev limiter set to 6200, so it looks like it might have gotten a few more hp.
Compared to your last dyno, you are down quite a bit in mid range due to being so rich. You can't see the torque on the second one but hp is over 10 less. 13-13.2 is where you make peak power.
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Sorry for making the dyno print so large. You should be able to scroll over to see the torque figures.
The first dyno run: my TCS is stock Fed Stromberg Twin Cam with emissions equipment removed. I wanted to document any horsepower change with each mod I did.
My first dyno run before any changes were made (1/18)...4th gear: 90.72 rwhp and 82.45 lbs torque
Dyno run after change to electronic ignition (2/18)...4th gear: 96.70 rwhp and 95.14 lbs torque
Dyno run after adding headers and carb rebuild (5/18)...4th gear: 99.01 rwhp and 91.87 lbs torque
Dyno run after cams reground from .350 to .383 (9/18)...4th gear:108.08 rwhp and 102.54 lbs torque
I thought the rev limiter was off (located inside the distributor) but instead it defaulted to 5500 rpms so I am sure if it had gone to 6500 rpms, the horsepower would be 2-4 hp higher.
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Those gains are significant. Over 17 HP with minor mods and tuning. The car must feel great. Any drivability issues with the re-grind?
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The car is very streetable. A lot of my driving is downtown Ft. Lauderdale and occasionally downtown Miami. The regrind numbers help explain it better. The duration is 268 degrees which is just under D spec Sprint cams, but the lift is .383" so I really didn't sacrifice any low end torque, but I get a huge mid-range surge of power past 2500 rpms all the way to redline. The Fed spec Europa is .350" and the Euro Sprint cam is .360" so I was ecstatic to get .383" with nothing other than the reground cam swap out (no head work). Twin Cam Racing who installed it evn did it without pulling the engine which really kept the cost down. When I did the last dyno my rev limiter was set to the wrong rpm and wouldn't let me go to 6500 rpm. I have since reset it and want to re-dyno the car to see if it will break 110 rwhp.
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Dyno run after change to electronic ignition (2/18)...4th gear: 96.70 rwhp and 95.14 lbs torque
Forgive me for being a little out of touch on some automotive basics, but how does electronic ignition get us 6 more rear wheel HP? Is this a programmable set-up like JB mentioned in an earlier post? I have an un-installed Pertronix kit that came with the car. If I can get 5% more HP just by installing it, I will definitely move installing it up the priority list!
Tom
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After I installed a Lumenition system on my TCS I notified that shining a timing light on the flywheel timing marks showed a very thin fine line while the stock point/condenser showed wide blurred line. I imagine the HP gain was due to very accurate spark timing.
Tom
74 TCS - 4605R
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Five percent is more than I would have expected. The condition of the points and condensor, the dwell setting, as well as the ability of the spring to keep the points follower in contact with the dizzy cam could play against a point/condensor system. If the coil was changed with the Pertronix ignition, that could affect the power also.
My motor was built with an Allison optical ignition that worked great till it didn't. I think the light failed since it was from long before LEDs. In Luminition does not use LEDs, I would advise swapping it with a Pertronix.
Those are nice numbers and you should be proud of the improvement you made, literarymadness! Good job!
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It is a Pertronix III. Most guys installed the II (~don't know if that makes a difference but it is hotter than the II) . All I did was Dyno the car at the same place before (and usually at 10:00 a.m. to keep the outside temperature the same) and after each change and show you the printouts. My guess for the drastic increase is that the original distributor was a little warn-out so the electronic ignition simply gave the motor what it was missing plus maybe one or two extra hp. Like I said wanted to be more scientific and look at dyno numbers only and not guess on horsepower. That is why I was asking other members to post their dynos...to compare. Dyno machine have a certain margin of error but if you use the exact same dyno everytime, it should be accurate in terms of relativity to a particular vehicle.
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Thanks BDA!!! and yes I went with a hotter 50,000 coil. The Pertronix is the D7190609 with rev limiter.
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Since motorcycle carbs were mentioned, I have been eyeing http://www.v-performance.com/products/air_fuel.html for after I repaint my car. They show some Lotus installs. No affiliation, of course.
Ken
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Since motorcycle carbs were mentioned, I have been eyeing http://www.v-performance.com/products/air_fuel.html for after I repaint my car. They show some Lotus installs. No affiliation, of course.
Ken
Very interesting Kendo. The Elan twin cam the show has some funky adapters between carbs and Stromberg manifold. Worth looking into.
t
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Looking closer at the Elan photo on the VPD website, it appars that the Mikunis are bolted directly to the head with their adapter eliminating the emissions manifold with the internal balance tubes. Be curious to hear how the Stromberg twin cam motor runs with out without balancing out the intake pulses. I was cautioned many years ago not to bolt the Strombergs directly to the head for this reason.
Does the difference in type of carburetor make a difference in not needing a balance system? The Mikunis are flat slides, I believe while the Strombergs are CD type.
Joji Tokumoto
Fallbrook, Ca
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A big thanks for the link to Vintage Performance. Those Mikuni conversion kits are quite intriguing, and no need to seek out a Weber head.
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Here is my two cents worth on the subject of carbs. The motorcycle carbs may or may not work great as delivered and may require a lot of calibration/ jetting. So, it could be a hassle. If you have an engine dyno, it fairly easy. I am sure the losses in the carbs would be less than the Strombergs so if done right, you will probably gain some horsepower.
As for the balance tube, I have twin SU carbs with no standard bypass butterflies and balance tube. It was like that when I bought it in 1986. I installed a balance tube by drilling out the front vacuum boss all the way through to the back runner, but not through the back vacuum boss. I then jb welded a 1/2” hard copper tube between the two runners. I then went through the ports and ground the pipe flush with the inside of the front and back runners. I has been in the head for 30 years and never loosened or leaked.
If it were me, and I wanted to improve on stock carbs, I would install a fuel injection system like this on https://www.classicfuelinjection.co.uk/ that appears to be SU carbs. That way, you have just throttle plates, injectors, controller and O2 sensor. You can adjust it until it is perfect with a laptop computer or maybe even an ipad. The engine will start immediately, idle and pull like crazy.
I have not done this because I am happy with performance as is.
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The flat-slide carbs have no butterflies, main or secondary venturis, no accel pump nozzles. At WOT there is just a thin needle (round) and an emulsion tube nozzle in the carb bore. That's it, that's all. Have gander down an Weber/Dell sometime. There's a lot of stuff in the way of airflow. If I had a Stromberg TC head, I would fit flat-slides.
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I know this is an older thread but feel like it's the right place. I finally got around to making a mount for my i-Phone so I could use the Perf-Expert app to get some sort of idea/base line of performance, specifically HP and Torque at the wheel. The motor is stock appearing with headers and fabricated air box with a cone filter. It still retains CB ignition; Pertonix III to be installed eventually. Internally it is built up with a steel billet crank, I believe JE pistons, .040 over(recent rebuild), and hot street cams from many years ago. Cams and crank were installed in the early '80's, probably sourced by the shop from Dave Bean. These results will need to be confirmed with a couple of more runs and eventually a real chassis dyno. The real reason I'm posting is to have others see if I've done my due diligence with spec entry and whether the results seem reasonable.
Thanks! Gerry
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Gerry,
I also used this app. I think your cda number of the frontal area but does not include the flow coefficient.
I used a cda of 4.57 ft^2 . This came from this source https://www.automobile-catalog.com/auta_details1.php.
The frontal area sited in this is close to your number total number. I am rooting for me to be wrong since my torque and hp calc will be higher.
A big frontal area number will increase the torque and horsepower calculation from acceleration.
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Gerry,
I also used this app. I think your cda number of the frontal area but does not include the flow coefficient.
I used a cda of 4.57 ft^2 . This came from this source https://www.automobile-catalog.com/auta_details1.php.
The frontal area sited in this is close to your number total number. I am rooting for me to be wrong since my torque and hp calc will be higher.
A big frontal area number will increase the torque and horsepower calculation from acceleration.
You, sir, are absolutely correct; I had entered just the raw frontal area without considering Cd! Using your Cda of 4.57 ft^2, the recalculated results are posted here. This is exactly why peer review is so important; others will catch when one has erred. Now I feel the results are pretty much what should be expected. Thanks!
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I was playing around with the program and found another issue with your input data.
The curb weight the program wants includes a full tank of gas (about 96 pounds). I weighed my car and it weighed 1679 lbs with a full tank of gas. It is a bit heavier than stock since it has ac.
Also, I entered additional weight as 215 lbs since I weigh 205 lbs and I take some tools with me. I would assume you don't weigh 110 pounds. Anyway, any increase in weight will increase your hp numbers.
I will post my results soon.
I will say your rpm red line is impressive. I only take mine to 6750 RPM, but it only has the stock crank.
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In response to weight, I had the Europa on scales years ago. IIRC, it came in within a couple of pounds of 1500#. When I ran this test, no spare or tools were aboard as when it was originally weighed. I entered my weight of 170# and entered 35% fuel load. The 110# payload listed is, I believe, not part of the equation as I cannot edit it in the app to zero. BTW, I only saw 7000 RPM on the tach; I assumed the app extrapolated!? I really need to install the Pertonix dizzy and converted tach (Smiths RVI 1432/01 with Spiyda RVC conversion). The original tach (RVI 1432/00) is suspect! It reads about 2900 RPM @ 60 MPH in 5th gear though. Unless I have some other parameter wrong, IE gearing? I still would like to make a couple of more runs in this configuration to establish consistent data. The problem is the only good stretch of road has a speed limit of 35 MPH. Jones Beach Ocean Pkwy, billiard table smooth and straight. The federallies will certainly not be happy with me! Not likely to be confuse with any other vehicles!!! C:-)
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I know. It is difficult to find a place to do the test. I went through the program and it calculates total weight by adding curb weight (full tanks) plus passenger weight, plus added weight, minus fuel weight if less than 100%. So, your 110 lb is your weight minus the fuel which I guess was around 1/3 full. If the 1500lb you measured was with full tanks, then your weights appear to be correct.
The program calculates rpm from speed, the gear ratio and the tire diameter so if you didn't take it to 8200rpm, then something isn't right.
Do you have a 5 speed?
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... I really need to install the Pertonix dizzy...
I don't have an opinion one way or the other and I don't have a Pertronix dizzy (I do have the Ignitor II module in my Lucas 23D dizzy) but you might be interested in a discussion about the Pertronix dizzy here: (https://vintagetechnologygarage.groups.io/g/cars/topic/123_distributor/83808952?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,0,83808952). It starts off with a discussion about 123 dizzies but on June 28th, Keith Frank gives his take on Pertronix dizzies.
If you don't know Keith, he is knowledgeable (especially about Webers) and as you might guess from his posts, is very opinionated. I don't think his comments should be discounted. As you will see from the posts, not everyone shared his view on the Pertronix dizzy but I thought you might want to hear what other users said about them.
If you decide to get the Pertronix distributor or even an Ignitor module, you might want to consider if it will allow you to statically time your motor. The Ignitor I will burn up if you leave the ignition on for too long. The Ignitor II is protected from that. When I upgraded from an Ignitor I to an Ignitor II, I went to statically time the motor and no plugs would fire. I called Pertronix tech support (they are very responsive and helpful - don't be shy if you have a question or problem) and the tech guy said that it was not expected to allow you to statically time and he promised me that it would work. It did. I suspect that the no-burn-up feature precluded the statically time capability. I wasn't too happy about that but I was happy about the fact that I couldn't burn up my module. I mentioned this on Keith's sidedraft groups.io list and he basically said I was an idiot. He swore that he used his Pertronix dizzy to statically time his engine. Neither of us had any explanation for this divergent experience. All this is to reinforce my suggestion to check about some details with the Pertronix guy to make sure you are getting what you want.
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Pfreen: IIRC, the scale measurement was done with 1/4 or less of fuel. Yes, 5 speed; originally 4 speed (352), now 365.
BDA: I have in my possession a Pertronix III. I also have spoken with a Pertronix tech, RE: advance curve. Was not to happy with the answer. 20° all in by 3500 RPM. I’ve had it apart and saw the advance limit plate stamped 10° which equals 20° at the crank. I’m thinking of trying to order extra weights and machining them to half thickness (except pivot bosses) to delay full advance to 7000RPM.
Comments/thoughts? Appreciate any and all…
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Correction: Pertronix III limit plate stamped 12°, not 10°. Therefore 24° at the crank.
BTW, the current dizzy is a 23D4 #41195 with a limiting plate stamped 10° = 20 at the crank and all in by 4000 RPM. I have it set to 14° static, 34° total.
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34° is high for a twin cam. If you just poodle about, maybe a stoplight grand prix now and then, you'll be ok. If you drive hard for extended periods, that's too much advance. IIRC, 28° is the recommended max advance. You can welded/brazed up slots to reduce total advance. All in at 4K is fine. All in at 7K will be too retarded in the mid-range.
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2766R (Gerry): My engine is now bored and stroked like yours and also with a Billet Steel Crank, so a 7000 rpm redline no problem. The crank could handles more but the powerband of my cam is 2000-7000 rpms and then falls off rapidly. I am running 12 degrees static with 19 degrees advance at 2500 rpm (31 total advance)and 22 degrees advance at 8000 rpm (34 total advance) where the limiter is set (Bluetooth 123 Ignition). Of course I never actually run the rpms past 7000. Those numbers were recommended by Steve Smith at Twin Cam Racing who did my engine rebuild. He races both a Ginetta G12 with a Lotus TC engine and an Elan Coupe with his TC bored and stroked to 1815 cc. I would not recommend those numbers to anyone with a stock TC engine.
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OK-I'll take both of your advice and retard back a few degrees. I don't drive hard most of the time these days. I do take it up through 3rd occasionally for fun though. It just seems happy at the current setting. I might take one more run using Perf-Expert before changing. In a perfect world, a few passes on a chassis dyno with A/F measurements would put things right.
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I do some long trips which involve mountain passes. I can spend 20 minutes, or more, flat out. I set my timing carefully.
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Gerry,
There is much info on ignition timing on the Lotus Elan site. This exchange seems pertinent to the discussion. https://lotuselan.net/forums/viewtopic.php?f=19&t=41666
Fyi, I run 14 deg at at 1000 RPM, 31 at 3000, and 33 at 7000 RPM.
I have 10.25:1 compression ratio, headers, Stromberg head, and the Kent cams L14 cam. I did find the L14 cam wanted more advance at idle than the sprint cam I had previously. I do have electronic, crankshaft triggered distributorless ignition, which does make it more accurate than a distributor. I have never experienced detonation in my tc and before I fitted a cold air intake, the air inlet was measured at 130 degrees in the Florida summer heat.
This another interesting article on the accuracy of different distributors.
https://classicmotorsports.com/articles/distributors-dyno/
The accuracy of your distributor may affect how advanced to go.
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and the Kent cams L14 cam. I did find the L14 cam wanted more advance at idle than the sprint cam I had previously. I do have electronic, crankshaft triggered distributorless ignition, which does make it more accurate than a distributor.
How do you find the L14 cams, what did you time them up to (mop or valve travel @ tdc ?)
they are an extremely versatile cam
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I did a lot of performance modeling and determined 106/106 was the best compromise of high end hp and low end torque. That is what Kent cams recommended as well.
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Just to compare. Mine is a UK spec BV on Dellortos, CR10.5-1 L14 cams 1.625 inlets and 1.4 exhausts. MBE Wasted spark distributor less ignition. Type 47 copy (ish) exhaust with silencer. NG1 transaxle. Standard cast crank. Soft cut at 7050 rpm hard cut at 7100 rpm.
I could spend a lot of money on Dyno time to dial in my AFR better, but for now it will have to do. Unless I decide to go an all steel bottom end and change the cams for McCoy's or similar.
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Europa88,
I assume your dyno numbers were on an engine dyno, not a rolling road?
If that is correct, my numbers are similar. However, I only have chassis dyno numbers.
On a chassis dyno, they measured 130 hp at 6250 Rpm. Peak torque was 115 ft-lbs at 5500 RPM. This is more than I expected so I am not totally confident in the numbers.
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Europa88,
I assume your dyno numbers were on an engine dyno, not a rolling road?
If that is correct, my numbers are similar. However, I only have chassis dyno numbers.
On a chassis dyno, they measured 130 hp at 6250 Rpm. Peak torque was 115 ft-lbs at 5500 RPM. This is more than I expected so I am not totally confident in the numbers.
Ahh no! They were measured on a rolling road and adjusted using the manufactures algorithm. 125BHP at the wheels. I do have a well ported and gas flowed head too.
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Here is a better image. My car is still making power at 7000 RPM and I think could make more at higher rpm if I could rev it safely. But with the original cast crank I would be crazy to try. I think it would make a few more BHP up to about 7300RPM then fall away. It would appear that your engine makes its peak lower down! Impressive though for a Stromberg head!
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I think if your af ratio was a little leaner (around 12.5:1), you would make more power. The dip in torque between 3500 and 5500 is probably due to the rich mixture (from accel pump?). That is what I found on the dyno since its easy to adjust the af ratio on my Hitachi SU carbs.
Anyway, the big intake valve you have should give you plenty of power and high end capability.
Thanks for posting. I think it is really great when people post their results so all of us can learn from it.
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Here are my engine Dyno results from the spring of 2021. 10.1 compression, steel crank from formula Ford, Crane/FAST electronic ignition, stainless header, Mikuni carbs, approx. 1700CCs. I believe this was done with no pully on the cam, and no muffler.
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Looks good