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RV-7A with GM's LS1 V8

Jim Reno

I'm New Here
In the September 2004 issue of Custom Planes magazine there is an article about putting Chevy's LS1 V8 in a RV-7A. The company doing this is Predator Aviation out of Peoria Arizona. I checked out their web site shortly after reading the article last year, but now they seem to have dropped off the faced of the earth. Anybody have any info about this? Or is anybody aware of other companies working with the LS1 engine for the RV?

Thanks,

Jim Reno
 
Ls1 V8

I had a website address for Predator Aviation but it doesn't seem to work now. The guy had moved from Arizona to Idaho and was working on an RV-10 to put the Chevy in. Haven't looked at his site in a while, and now it doesn't work.

Another website you might look at is Vestav8.com. Jason Day is offering a LS-1 package that looks very interesting. Check it out.

Bill Gipson
RV-10
N730WL
Fuselage
 
Sport aviation LS1 article

There was an article in the EAA magazine in last three months with a LS1 installation in a homebuilt (not a RV). The installation I believe was home grown and it was flown, including a x-country trip to Oshkosh. As far as the LS1, I saw a show on how to rebuild a LS1. Knowing small block Chevy?s, the LS1 is a completely different. Belted air company has info on engine auto-aircraft conversions. Their reduction works on V6 and V8 engines. They have flown some RV conversions: www.beltedair.com

Another company that has some info for V8 conversions using a ZZ4 engine:
http://www.team-38.com/engine_faq.html#What is the overall cost

I am not a big fan of engine conversions myself but respect those who pioneer. Check out the thread in this forum on "Are you ready to be a test pilot". Some real good insight on auto engines.

Good Luck, George
 
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chevy small block--sorry no info

32206025chevyleft2zs.jpg


32206026chevyrifront3hc.jpg


32206031chevybody7iu.jpg
 
Jim Reno said:
In the September 2004 issue of Custom Planes magazine there is an article about putting Chevy's LS1 V8 in a RV-7A. The company doing this is Predator Aviation out of Peoria Arizona. I checked out their web site shortly after reading the article last year, but now they seem to have dropped off the faced of the earth. Anybody have any info about this? Or is anybody aware of other companies working with the LS1 engine for the RV?

Thanks,

Jim Reno

Jim, while I like the construction of the LS1 as a possible alternate engine source, it seems like just too large a package for a RV-7 without a wildly exaggerated cowling. Radiator location would be tough too. You would have to do a belly scoop or exposed radiator to handle the power of the LS1. While it may have been done I think it would be a packaging nightmare. The RV-10 is bigger and might have better chance of it fitting decently.
This ignores the fact that if you use reduction and get anywhere near the rated HP you are 50% over Vans recomended maximum for an RV-7! If you are set on fitting a 'V' engine in a RV a V6 is a better fit for the 2 place aircraft.
Bill Jepson
 
Stallion?

Mark, you say "no info", not sure if you are refering to the engine only, or the a/c also---------anyway, it looks like a Martin Holliman design called a Stallion.

I have seen the engine package at Oshkosh, and sun-n-fun, but cant remember the company name, however as I recall they were targeting the Lanceair 4 crowd.

Mike
 
Mike S said:
Mark, you say "no info", not sure if you are refering to the engine only, or the a/c also---------anyway, it looks like a Martin Holliman design called a Stallion.

I have seen the engine package at Oshkosh, and sun-n-fun, but cant remember the company name, however as I recall they were targeting the Lanceair 4 crowd.

Mike

Mike,
I believe that was "Engine Air" and I believe they were in Georgia. They had some initial good results, but then had some problem mass producing their PSRU. I don't know if anyone was left hanging when they closed their doors but it seems likely. They were refusing to go to the LS-1 at first. Don't remember the reasoning. They seemed like they bit off more than they could deliver. The package was even supposed to include automotive style air conditioning! One of their packages in a Lancair 4 was second in the air race to OSH one year behind Hoot Gibson in a Sea Fury.
Bill Jepson
 
I ran across this RV-7A today at KLGB. Did a double take. Decals on the side say 400HP - Airconditioned! The dataplate listed the engine as an LS-1.

A search of VAF brought up this thread so for posterity I'll add these photos.

IMG_1044-M.jpg


IMG_1045-M.jpg


Looks like it has been sitting outside for a while, so maybe it is no longer flying.
 
400 HP 7A

It just seems that kind of HP is completely wasted in an RV...

How about putting it in a Harmon Rocket where you can actually throttle it up! :)

Doug

RV-3A Sold
RV-9A Mazda 13B / FWF
 
I ran across this RV-7A today at KLGB. Did a double take. Decals on the side say 400HP - Airconditioned! The dataplate listed the engine as an LS-1.

A search of VAF brought up this thread so for posterity I'll add these photos.

IMG_1044-M.jpg


IMG_1045-M.jpg


Looks like it has been sitting outside for a while, so maybe it is no longer flying.

Or possibly it has never flown.

That's OK you can fly it first... perhaps not much fun to taxi on soft grass.

If only it had a small wheel on the back end and a pair 6.00 x 6" on adequate main gear legs sprouting from the motor mount.
 
If this is the airplane I'm thinking of, the airplane has flown quite a bit. The builder used to post on another forum I frequent.
 
LS1 V8

Looks like I am a little late on responding as I am newer to this forum.
This is my RV7A based out of LGB and it was originally built by Predator Aviation and yes they were in AZ and moved to IL and Chris Opperman who owned Predator had a massive heart attack and passed away.
I purchased the plane a few years ago and have worked with another Chris that was Opperman's right hand man that lives local and the plane is back flying.
It has been featured in a couple publications prior to me owning it and the performance was stated at 4,000 ft min climb rate and a top speed at 236 knots with a 9 gal hr fuel burn.
I have approx. 200 photo's of the entire build and will be looking at selling the plane the first of the year.

I hope this helps with some of the questions :)
 
Looks like I am a little late on responding as I am newer to this forum.
This is my RV7A based out of LGB and it was originally built by Predator Aviation and yes they were in AZ and moved to IL and Chris Opperman who owned Predator had a massive heart attack and passed away.
I purchased the plane a few years ago and have worked with another Chris that was Opperman's right hand man that lives local and the plane is back flying.
It has been featured in a couple publications prior to me owning it and the performance was stated at 4,000 ft min climb rate and a top speed at 236 knots with a 9 gal hr fuel burn.
I have approx. 200 photo's of the entire build and will be looking at selling the plane the first of the year.

I hope this helps with some of the questions :)

If you can put 9 gal of fuel in the tank and cover 236 nautical miles over a period of 1 hr, I will give ya $100 hard cash purely for witnessing the demonstration.
 
"the performance was stated at 4,000 ft min climb rate and a top speed at 236 knots with a 9 gal hr fuel burn" Indicates the fuel burn rate was achieved while flying at 236 knots but probably not what he meant.
 
Mike,

Sure is a unique and interesting aircraft! Can you provide links to the publications that you referred to (if available), or perhaps provide some details of the build. It would be interesting to hear about the mods required to support the engine and to work through any weight and balance issues with the alternative engine, as well as structural strength mods for the higher speeds achieved. It would also be interesting to hear about performance measurements you have taken since you have been flying it (power settings and fuel flow at max speed, cruise speed, etc). Also would love to hear about engine temperature management.

Neat airplane...looking forward to hearing and seeing more about it!

Cheers,
Bob


Looks like I am a little late on responding as I am newer to this forum.
This is my RV7A based out of LGB and it was originally built by Predator Aviation and yes they were in AZ and moved to IL and Chris Opperman who owned Predator had a massive heart attack and passed away.
I purchased the plane a few years ago and have worked with another Chris that was Opperman's right hand man that lives local and the plane is back flying.
It has been featured in a couple publications prior to me owning it and the performance was stated at 4,000 ft min climb rate and a top speed at 236 knots with a 9 gal hr fuel burn.
I have approx. 200 photo's of the entire build and will be looking at selling the plane the first of the year.

I hope this helps with some of the questions :)
 
Hints of a lot of nay sayers, Dang, I could have had a V8! reminds me of all the non believers in HS that said you can't put a V8 in a Pinto....until I drove to school with it in the early 80s.....may not be practical but its COOL! :cool:
 
I had a website address for Predator Aviation but it doesn't seem to work now. The guy had moved from Arizona to Idaho and was working on an RV-10 to put the Chevy in. Haven't looked at his site in a while, and now it doesn't work.

Another website you might look at is Vestav8.com. Jason Day is offering a LS-1 package that looks very interesting. Check it out.

Bill Gipson
RV-10
N730WL
Fuselage

Hey Bill, what's the actual web address? It might well be archived in the Wayback Machine.

Mike, I, too, would like to see more info on the plane. Empty weight, cg, any airframe mods made to accommodate the extra engine weight, and of course, performance numbers.

Thanks,

Charlie
 
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Other half

Over the years, seen lots of auto engine ideas. However, the real challenge is converting those horses to something that the prop can use. I?d be interested in seeing the portion between the engine and the prop. Plane looks great!
 
Add engine designer Jack Kane to the naysayers column.

...When you do a true, accurate, apples-to-apples comparison of the total, firewall-forward weight of a complete, flying Lycoming or Continental powerplant against that of a complete, flyable liquid-cooled powerplant of the same or greater power (real, measured SAE Horsepower, not "BlantonPower"), the liquid-cooled installation will almost always outweigh the Lyco-Nental by a considerable amount. There is a table at the end of this page showing details supporting this statement...
 
That's the car I needed in Junior College Bret! My Mom's Pinto struggled when half of our offensive line climbed into it on the way to the post-game party. Tailback driving, Fullback right seat, Center and Guards in the back...phone-booth fit! We may have been slightly over-gross for the 1600cc "Pintera"! :D Ah for a V-8 that day!

How long did your tires last...that one ride to HS? :D

But we digress! Though auto conversions have challenges, its fun to see them work, and a buddy is building an LS2 Single Seat Thorp, so any info on this project is welcome. Gonna take a look at the links!

Cheers,
Bob

Hints of a lot of nay sayers, Dang, I could have had a V8! reminds me of all the non believers in HS that said you can't put a V8 in a Pinto....until I drove to school with it in the early 80s.....may not be practical but its COOL! :cool:
 
I've got many clients flying successful auto conversions. Might weigh a bit more but are way cheaper to buy and overhaul than traditional Lyconentals.

We're working with some new partners in 2018 who already have flying examples and are intending to offer FF packages.

Just gotta follow the right recipe, pay attention to the details and it can work very well.

While I respect Jack Kane very much, it almost seems he's unaware of the many people who have hundreds of successful flight hours on certain engines and gearboxes. There is more than the one EPI offered solution to the various given problems for successful conversions.

The first step is picking a suitable engine, weight and power wise for your project. Too many folks fail right here at step 1.

"People who say it cannot be done should not interrupt those who are already doing it"
 
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That's the car I needed in Junior College Bret! My Mom's Pinto struggled when half of our offensive line climbed into it on the way to the post-game party. Tailback driving, Fullback right seat, Center and Guards in the back...phone-booth fit! We may have been slightly over-gross for the 1600cc "Pintera"! :D Ah for a V-8 that day!

How long did your tires last...that one ride to HS? :D

But we digress! Though auto conversions have challenges, its fun to see them work, and a buddy is building an LS2 Single Seat Thorp, so any info on this project is welcome. Gonna take a look at the links!

Cheers,
Bob

Back in the 80s no money but good times racing on Ortega hwy 74 with those other performance cars, the look on their faces when the beater pinto went roaring by them :D
https://i.imgur.com/9aMBceH.jpg?1
 
Bret,
Great photo of the Pinto.......love the air cleaner just sticking through the hood! Thanks for sharing.
 
the liquid-cooled installation will almost always outweigh the Lyco-Nental by a considerable amount.

I'm not an expert engine designer, but my own research data shows this isn't necessarily true. Bear in mind I only did one engine comparison, but it seems Jack's analysis only examined one alternative engine as well, so take either of these examples in that context.

Here is a link to the weight analysis that I did on a 6 cyl Subaru versus a Lyc O-360:

https://deej.net/sportsman/engine-weight.html

-Dj
 
I'm not an expert engine designer, but my own research data shows this isn't necessarily true. Bear in mind I only did one engine comparison, but it seems Jack's analysis only examined one alternative engine as well, so take either of these examples in that context.

Here is a link to the weight analysis that I did on a 6 cyl Subaru versus a Lyc O-360:

https://deej.net/sportsman/engine-weight.html

-Dj

All of the empty weight data I have seen that was obtained from weighing finished RV-'s equipped with a 4 cyl Sub engine were at a minimum 80 lbs and typically 100 lbs heavier than a similarly equipped airplane with a 4 cyl Lyc and metal prop, so it would surprise me if your theoretical empty weight actually worked out to be close to the same using a 6 Cyl Sub engine.
 
All of the empty weight data I have seen that was obtained from weighing finished RV-'s equipped with a 4 cyl Sub engine were at a minimum 80 lbs and typically 100 lbs heavier than a similarly equipped airplane with a 4 cyl Lyc and metal prop, so it would surprise me if your theoretical empty weight actually worked out to be close to the same using a 6 Cyl Sub engine.

Scott, what would you say the typical weight is for an RV7A with 4 cyl Lyc and metal prop?

Bevan.
 
it would surprise me if your theoretical empty weight actually worked out to be close to the same using a 6 Cyl Sub engine.

To clarify, I used actual weight data, not theoretical data. If you or anyone can find an error with the data I posted, I can look into it.

The weights I used for the individual parts came from either direct measurement with scales, or from published manufacturer data.

The entire FWF O-360 and H-6 Subaru packages were weighed with certified scales.

I tried to be as thorough as possible with the research knowing full well it would be critiqued. I've been sharing this data for about 8 years now, and to date only one person has found an error with one of the part weights early on, and it was corrected.

-Dj
 
Scott, what would you say the typical weight is for an RV7A with 4 cyl Lyc and metal prop?

Bevan.

With a parallel valve 180 and fixed metal prop, a bit over 1110 -1125 lbs is a common empty weight. With a 200 and constant speed 1150 -1160 lbs is common.

There is of course lighter, and heavier, but I think these weights are close to the overall average.
 
To clarify, I used actual weight data, not theoretical data. If you or anyone can find an error with the data I posted, I can look into it.

The weights I used for the individual parts came from either direct measurement with scales, or from published manufacturer data.

The entire FWF O-360 and H-6 Subaru packages were weighed with certified scales.

I tried to be as thorough as possible with the research knowing full well it would be critiqued. I've been sharing this data for about 8 years now, and to date only one person has found an error with one of the part weights early on, and it was corrected.

-Dj

Fair enough..... maybe some things can be done that are beneficial for weight reduction on a Sportsman, but actual weights of similarly equiped RV's with the only primary difference being the powerplant, show the weight differences to be significant.

So it sounds like what you are saying is that it was still research and you never actually completed the build of a Sportsman to the point of being ready to fly, and measured the actual finished airplane empty weight?
 
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So it sounds like what you are saying is that it was still research and you never actually completed the build of a Sportsman to the point of being ready to fly, and measured the actual finished airplane empty weight?


As stated on the web page, I measured everything from the firewall forward (not including the actual firewall, and I didn't include a nosewheel if there was one).

Is there anything aft of the firewall that would make a significant change in the final empty weight of the aircraft? Without a doubt there are a wide variety of things that would make one aircraft weigh more than another, even with the same engine type installed (tailwheel versus nosewheel, primer versus not, panel item selection, upholstery, etc). You can't compare the final weights of two different aircraft and then determine that the FWF is what is making the difference, unless you know the exact weight of the individual FWF installations. In general, no one knows this because they never measure it.

The whole point of me doing this research was because everyone keeps guessing on weights, and no one had actually measured the difference that I could tell. When Frank removed his FWF and weighed it, I saw an opportunity. I went into this fully expecting that the Subaru would be significantly heavier, because that's what everyone keeps claiming. I was surprised when the Subaru came in only a couple of pounds heavier. So, I says to myself, how can I verify that Frank's weight was accurate? I then made a list of everything FWF on a typical Lycoming installation, and started gathering weights of all of those individual parts. The total weight of all of the Lyc parts came within a reasonable difference of the actual measured Lyc FWF package, so I surmised that the measured weight was accurate, or at least close enough for a reasonable comparison.

As I stated on the web page, it is most definitely possible to put together a Lyc FWF package that is lighter than Frank's. Frank was using a typical heavy, metal, hydraulic constant speed prop, and even just replacing that with a lightweight composite electrical variable pitch prop would make it lighter, and if you custom selected each FWF part based on weight, you could make it considerably lighter.

As I stated at the beginning, this is only one engine comparison, and not nearly enough data to draw any conclusions about the weight comparisons in general, but we definitely can conclude that at least one Lyc FWF installation was about the same weight as a comparable Subaru FWF installation, and therefore possible to have similar weights among other installations. How likely it is to have similar weights is impossible to tell without more data.

-Dj
 
My Mazda Renesis with RWS reduction drive, radiator, oil cooler, modified stock cast iron/stainless exhaust manifold, big heavy muffler (required), hoses, ignition coils, injectors, water 'swirl pot', two full size 55 amp alternators, engine mount adapters (significantly overbuilt), literally everything except fluids and propeller, weighs 335 lbs, sitting on a scale. And several pounds of the stock motor mount were removed to adapt it to the rotary, so that would lower the equivalent weight by at least 3 lbs. If I were to start over on the mount and a couple of other details, I could probably shave off another 10; possibly 15.

If you don't believe it, it's off the plane right now while I finish up firewall details. Bring your scale.

What was it that an angle valve IO-360 weighs, again, complete with all baffles, exhausts, hoses, oil cooler, ducting, dual alternators, etc?

Charlie
 
What was it that an angle valve IO-360 weighs, again, complete with all baffles, exhausts, hoses, oil cooler, ducting, dual alternators, etc?

Lycoming says an IO-360-A3B6 is 325 lbs w/ mags, injection, and starter, dry. No baffles, exhausts, hoses, cooler, or alternators.
 
What was it that an that an angle valve IO-360 weighs, again, complete with all baffles, exhausts, hoses, oil cooler, ducting, dual alternators, etc?

According to Lycoming, the IO-360-A series of engines have dry weights not including accessories from 324 to 335 lbs:

https://deej.net/sportsman/reference/Lycoming-360-Engine-Insert.pdf

Note that weight does not include any of the baffles, exhausts, hoses, oil cooler, ducting, alternators, etc.

I do have some of those weights posted on my web page:

https://deej.net/sportsman/engine-weight.html

-Dj
 
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Love it Bret! :D

Bryan Adams sez I need to come down and see your panel...of course Steve S and Bob K have me shackled to the drill press working on stub spars for the new wing...but soon! C'mon up and check it out if you like!

Mike (LS1RV7A)...any chance you can share aircraft and engine performance data...still very interested in how your mo-chine is flying!

Cheers,
Bob

Back in the 80s no money but good times racing on Ortega hwy 74 with those other performance cars, the look on their faces when the beater pinto went roaring by them :D
https://i.imgur.com/9aMBceH.jpg?1
 
Subie Vs. Lycoming Empty Weights

All of the empty weight data I have seen that was obtained from weighing finished RV-'s equipped with a 4 cyl Sub engine were at a minimum 80 lbs and typically 100 lbs heavier than a similarly equipped airplane with a 4 cyl Lyc and metal prop, so it would surprise me if your theoretical empty weight actually worked out to be close to the same using a 6 Cyl Sub engine.

After following the "alternative engine" movement since the early 90's; the 80-110 lbs. heavier weight of a Subie has been pretty much an expected "standard" to plan on, and drove most builders to place batteries in the baggage area vs. on the firewall as is the RV "std". These comparisons back in the "old days" were generally comparing the finished Egg. Subie to an O-320. With O-360s running about 25-30 lbs. more, that will cut into the overweight condition by a little bit...

Doug Lomheim
RV-9A Mazda 13B / FWF
 
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My 6A now weighs in at 1166 lbs. empty with lots of paint, full steam gauges, roll servo, heavy cowling repair, 2 full size AGM batteries, ELT, turbocharger and intercooler. It would be easily below 1100 lbs. with lithium batteries, no turbo, a glass panel and a fresh cowling.

I did a detailed weight analysis a couple years ago weighing every component of an EJ25 conversion (my conversion as an example) and it came down to pretty much a wash against a PV Lyc 360 with Hartzell 2 blade C/S metal prop. The Sube numbers used a 3 blade MT electric C/S composite prop because that's about the best match for them. I think the final number was 11 pounds less for the Sube but that would be similar if you used a composite prop on the Lyc. The Sube would be 170hp.

Doesn't have to be heavier but you really need to pay attention to every aspect and detail.

Obviously an LS V8 is not in the same hp or weight class with a 360 Lycoming.

The LS is very light for the hp though- around 420 lbs. with accessories (alt, starter, water pump etc.- no gearbox). My friend Jeff Ackland runs a custom built LS in the P85 which is essentially a Radial Rocket with the M14P replaced by an LS. I believe the overall weight is similar but the LS has around 100 more hp. Costs less, is faster, burns less fuel and basically no oil. It also looks and sounds better IMO. Parts are readily available and inexpensive compared to M14 parts.



Another partner is flying an LS powered Moose, again replacing the M14 radial.

Both aircraft have been flying for a while with no significant issues.

We're working with 2 other customers at the moment installing LS engines in a Lancair IV and Velocity respectively. Will be interesting to see how those pan out.

The LS seems like a reasonable replacement for angle valve 540 Lycomings/ Conti 550s and M14Ps weight wise, while offering up 70-170 more hp.
 
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I did a detailed weight analysis a couple years ago weighing every component of an EJ25 conversion (my conversion as an example) and it came down to pretty much a wash against a PV Lyc 360 with Hartzell 2 blade C/S metal prop.

If that is true Ross, then why are there countless examples of RV's built with a Sub engine that were about 100 lbs heavier than a lyc powered airplane similarly equipped in the panel, etc.
Did everyone else except for you get it totally wrong?
Note- I am not arguing for or against alternative engine usage. what I am arguing for is real substantiated data. People complain about the negative vibe towards alternative power here on VAF and elsewhere. I think that is largely manifested by the lack of transparency by many (note I didn't say all) that have gone that route (manufacturers and users alike).
If users were more willing to be honest about the good and the bad (whether that be actual/honest completed empty weights or something else), then I think there would be an entirely different feel to the discussions.

BTW, my opinion is that you have always been one to be rather transparent about about the good and the bad, and have been a shinning example of the right way to work through an installation, but having said that I am perplexed at your explanation of why your airplane is 1166 but could be lighter.

If we removed/changed all of the items you mentioned, on my O-360 powered RV-6A that it has (ELT, heavy battery, and it actually has two AP servos to remove, etc.) then it would be under 1040 lbs, so at least a 60 lb difference. With my current empty weight of 1061, your current empty weight is 105 lbs heavier. I realize that includes turbo and intercooler, etc, but even discounting those it appears it would be a long ways from being a wash. Especially if to be fair we us the weight of a Lyc powered RV using an MT prop (which would not be unusual, because a lot of people use them or Whirlwind).
 
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These comparisons back in the "old days" were generally comparing the finished Egg. Subie to an O-320. With O-360s running about 25-30 lbs. more, that will cut into the overweight condition by a little bit...

The actual weight diff. between a similar O-320 and O-360 (both with hollow crank, etc) is only 8-10 pounds.
The weight of an O-360 Hartzell is a bit heavier than the one for an O-320 so if a Hartzell prop was used as a standard I think the O-360 RV will only be 10-12 pounds heavier.
 
why are there countless examples of RV's built with a Sub engine that were about 100 lbs heavier than a lyc powered airplane similarly equipped in the panel, etc.

There are MANY reasons why two similarly equipped aircraft weigh differently, as we can see even with aircraft that have the same engine installed. Even primer versus alodine versus nothing can be 5 to 30 lbs difference depending on how much and how thick the internal primer was applied.

You simply cannot judge with any level of accuracy the difference in weight a FWF makes unless you know exactly how much the two FWF packages each weigh, and not very many people have done this.


what I am arguing for is real substantiated data.

That is precisely what I tried to provide, at least for one specific comparison that I had data for. Two others have now come forward with their data, another Subaru and a Mazda.

I have no doubt that there are some Subaru installations that weigh more than a Lyc installation, but what boggles me is when data is provided to show that a Subaru (or Mazda) installation can weigh about the same as a Lyc installation, people seem to disbelieve it. There is no reason not to believe that both situations can be true.

-Dj
 
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