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Discussion Starter #1
This is my first thread here, and I want to say that I think this forum seems to have a nice group of members.

I became the owner of a 2001 Honda Insight 6 days ago. I work as a power generation engineer for Microsoft, and before this job, I worked in the racing engine part design for 7 years.

I bought the car with the intent of swapping the engine to a Honda k24a2, however, I think it would be much more a challenge to reach my power goals with the stock engine.

The stock engine is very de-tuned. Specific output (hp/L) is very low, which is to be expected for an engine that has a 6200rpm ceiling, but this doesn't explain the low specific torque (ft-lbs/L).

On an engine with so many outstanding and exotic measures taken to reduce Fmep (frictional loss), I expected to see excellent BSFC (brake specific fuel consumption). (BSFC is the measure of how much useful energy an engine creates per unit of fuel.) I was dissapointed.

I started to design a cam profile better optimized towards my needs, and I was very thrilled with the mechanical limits and properties of the valvetrain. I also measured the stock (true lift) lift at the valves.

First, some pictures of our beautiful valvetrain design. If you note the use of needle bearings in most piviots (excludeing intake rocker shaft piviot which appears to be a bushing), the use of forged aluminum exaust rockers, and other weight saving measures, you will see that no expense was spared in its construction.

Above picture.
http://www.ejlin.com/albums/album41/DSCF0601.sized.jpg
[mod edit: Removed img function. Please see the rules. Links to appropriate pics always welcome]

Picture of beautiful forged aluminum exaust rockers. Note the thin washers to retain the needles on each side of the rocker where it mounts to the shaft.
http://www.ejlin.com/albums/album41/DSCF0607.sized.jpg


This picture shows the primary rocker with its needle roller, and the vtec-e rocker cuddled up against it. The little nubbin on the upper corner of the vtec-e rocker is the houseing for the vtec pin mechanism.

http://www.ejlin.com/albums/album41/DSCF0608.sized.jpg

Here is a measurement of peak exaust valve lift. It's unreadable in the picture, but peak exaust valve lift was 0.300" (limted to +-0.01" precision of fixture)

http://www.ejlin.com/albums/album41/DSCF0606.sized.jpg

This picture shows the measureing of peak intake valve lift. The depth of field for the camera was not able to capture the dial in a readable form, but the lift was 0.322".

http://www.ejlin.com/albums/album41/DSCF0605.sized.jpg


Now, for the most important data. Unlike many engines, the peak lift is not limited by coil bind, but rather by the bottoms of the keeper tangs contacting the upper edge of the valve stem seal. This occurs at roughly 0.610" of lift. This is a massive amount of lift for an engine with such such a small valve face, much beyond the areas of diminishing returns in reguards to valve lift vs increased flow. The clearence around the lobes of the cam in the head was also generously recessed, and I see no reason why the engine can't easily handle a cam with lift pushed into the 0.500" range. I will be doing this when I purchase a spare insight engine and have the camshaft spray welded to build up the lobe enough to have adquate material to work with with out needing to reduce the base circle (which would effect ramp-rate angles in a negative way).

Also, as far as tossing in a cam with more lift and duration on the stock engine, I belive you would be loseing power. I measured stock exaust pressure at peak RPM to be 7psi in the manifold! This is as poor of an IMP to EMP ratio as I've ever measured on a non-turbo charged engine, and a factor which is certianly a large part of the low BSFC, output, and poor response.

I plan to solve this problem by carefully machining off the terrible intigrated exaust manifold cast into the head, welding up the low places, drilling and tapping holes near each of the 3 exposed ports, welding up the exposed water passages and possible oil return passages, then decking both surfaces of the head flat again (as the chamber side will be warped as well from the welding).

Once this is done, a proper 3-1 narrow long tube header with choke merge collector will be fabricated. From very rough calculations, this will give the engine more of a boost than haveing the IMA enguaged on full assist at all times, yet will require less fueling than before (BSFC improvement).

To sumarize, substantially improved economy and performance as well as performance potential for future modifications.

Best Wishes,
-Luke
 

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Interesting :)

One point: You said "... this doesn't explain the low specific torque (ft-lbs/L)". Maybe the low torque was a deliberate design decision. After all, the engine is matched to a high-torque electric motor, and the system presumably optimized for fuel economy.

And I can't help but wonder what Microsoft is doing that requires power generation engineers...
 

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Discussion Starter #3
This engine was optimized to lower friction, but many decisions were which sacrifice fuel economy in favor of a quick cat functional temperature being reached without the need for a large starting enrichment (responsible for a large part of the HC emmisions in most modern engines).

As far as why Microsoft needs power generation engineers...

These are a few of my 16 babies. They generate the power to ensure that 85,000 servers in our datacenter are not effected no matter what games the power company decides to play. These servers host sites like MSN, Hotmail, and thousands of others you may be familiar with, but this is getting far off topic now...

http://www.ejlin.com/albums/album11/P8090030.sized.jpg

http://www.ejlin.com/albums/album11/P8090021.sized.jpg


Best Wishes,
-Luke
 

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Hi Luke. Welcome to the forum. Someone else with a non digital caliper.* 8)

Several members here have turbo charged their Insights. There are also two Drag racing Insights, a class winning Rally Insight running on E 85 in Britain, Active Insight racing members in Ontario and Callifornia, and at least one all electric Insight.

We welcome contributions to the general knowledge base. Naturally there are those here who would like to see you improve the efficiency of the engine, and others who will welcome any additional power.

I believe the integrated exhaust manifold was also to help keep our little engine from freezing its nuts....and bolts off in the winter. :D Stainless headers perchance?

*OK, I admit I recently caved and got 2 digitals :oops:
 

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One thing I have wondered about is whether there is anything in the engine related to low speed operation. I frequently find myself running it at around 1000 rpm with a load, which in most other cars will hardly work at all. There's no special notice in the instructions about lugging the engine, but high-mileage driving techniques seem to encourage that sort of operation...
 

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liveforphysics said:
To sumarize, substantially improved economy and performance as well as performance potential for future modifications.
I will be interesting to follow your progress in regard to re-engineering the Insight and improving its MPG. Don't fail to take account of intake and exhaust flow dynamics and the lean-burn cycle that enables Insight hyper MPG (5 speed models only).

http://www.insightcentral.net/encyclopedia/enlaf.html

And you've got Honda at an advantage since its likely your modifications will not be able to meet emissions requirements either.
 

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I don't think Honda put all the focus on just gas mileage and power, back in 1998 the CRX HF would get 60-65 mpg and would hold it's own against the insight on a straight line. The Insight does have a better crash rating and is 100 time cleaner.
I do believe a tuned header of some kind would help and a little more compression and lift on the high left part of the cam.
I will be interested on your progress.
 

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Hi K-Sight,

The last year for the HF was 91. ;) I owned one and put 240K miles on it. It was good, but for whatever reasons (one was no MPG game gauge) the best I ever got was 57MPG.

Yes, other Insighters have reported better results in their old HF's. YMMV. ;)


HTH! :)
 

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Sorry Typo, I ment 1988. The CRX HF was 1988 to 1991 only, The Civic VX was another gas sipper which went to 1992-1995.

I had a CRX HF which on the Highway I got 60+ mpg every time running around 60-65 mph. I have owned a couple of Insights, I have had as high as 82 running 55-60mph with no AC and very easy driving.
My point is , I think Honda could achieve 100mpg + but there would be sacrifces.
I love the insight and the technology is amazing, But looking at the big pictures...Gas mailege really has come a long way from 1988.
 

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K-Sight said:
The CRX HF was 1988 to 1991 only,...<snip>
Don't forget its carburated predecessor either :!: ;)

IIRC for 2 years prior to the 88 body style the CRX came in an HF version too. Careful driving could yield a whopping mid 40's MPG :!: :shock: ;) IIRC highway MPG rating was 51ish :?: T'was a rare breed indeed. Back in the .69/g gasoline days.
 

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If you are looking at getting a new camshaft ground, something else you need to look into to valve timing. I believe honda built in alot of "miller/atkinson" cycle into the engine where the intake valve is left open during the first part of the compression stroke. This turns a high static compression ratio into a more normal effective compression ratio. One other effect of miller/atkinson is poor low end power. Something the insight engine definitely has. (Toyota admits to using miller/atkinson in their hybrid engines).

If a new cam grind which dials out some the miller/atkinson can result in big gains in low end torque. But then High Octane gas may also be required.

One of the problems with BSFC measurements is that they take place at full throttle and usually at peak HP and/or peak torque. For BSFC reflect real world efficiency it needs to be measured at real world throttle position and RPMS.

It's also interesting to hear about your findings on integral exhaust manifold. It's definately not equal length runners which means at certain RPMs there can be pressure spikes. I've kind of wondered why honda did it. I'm guessing it is for weight savings and allows closer cat mounting (which means a faster cat start on a cold engine).

You need to remember honda had 3 areas of concern in engine development: Efficiency, Cleanliness and Weight.
 

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flunkysama said:
I've kind of wondered why honda did it. I'm guessing it is for weight savings and allows closer cat mounting (which means a faster cat start on a cold engine).
IIRC and its outlined here:

Sticky: F.A.Q.: IMA and Insight Design Concepts White Paper
http://www.insightcentral.net/forum/vie ... php?t=3174

Faster warm-ups (lower emmissions) and better thermal efficiency.

Remember, being the gas sipper that the Insight is there are considerations for maintaning optimal engine temperature for maximum MPG.

The cardboard "trick" and hot air intake seem to substantiate the theory.
 

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flunkysama said:
I believe honda built in alot of "miller/atkinson" cycle into the engine where the intake valve is left open during the first part of the compression stroke. This turns a high static compression ratio into a more normal effective compression ratio.
Hmm, that's interesting. I hadn't heard any talk of this on Honda's, only Toyota's. The Prius uses a 13.5:1 CR (well that's the expansion ratio, the true CR is quite a bit lower). The Insight uses a 10.8 or 10.3:1 CR which is still quite high (especially for 87 octane) but maybe there's another way Honda keeps the motor from pinging. If the Insight does use some Atkinson cycle, it's much less that the Prius.

Insightful Trekker said:
Don't forget its carburated predecessor either :!: ;)

IIRC for 2 years prior to the 88 body style the CRX came in an HF version too. Careful driving could yield a whopping mid 40's MPG :!: :shock: ;) IIRC highway MPG rating was 51ish :?: T'was a rare breed indeed. Back in the .69/g gasoline days.
My mom drove a Honda back in the 70's that would get well over 40 mpg.
 

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Discussion Starter #14
Flunkysama- My estimates located lobe centers around 103deg, with common IVO and IVC events. I didn't find a hint of miller cycle in the profile on my 2001 MT. Could this be a model specific profile?

Kapps- Bore size and abnormal combustion vary directly. Small bore engines with decent mixture turbulence and functional piston squish pads can reach much higher compression ratios than 10.8:1 with no abnormal combustion concerns with 87 octane. This was clearly a case of Honda swapping economy and output again in favor of lower NO emmisions.

Now, kinda back to topic ;)

The purpose of the integrated e-manifolding is for two reasons. One being weight, and possible cost reduction (depending on how many steps it added to the sand-core). And the main reason is being something which we plainly see given priority over economy in the engines design, which would be environmental impact reduction.

Most engines require a period of extra rich operation shortly after a cold start to ensure the cats are stimulated enough to 'light off' and begin operation, as HC's passing over cold Pt has no reaction. Rich warm up operation ensures extra hot exhaust gas stimulates the cat to function as soon as possible.

When building an engine for an application which requires cats (only happened twice in my life), I choose to light the cat via excessive timing retardation. This is quite loud and prone to damage the exhaust seat/valve if the engine were to do anything but idle during this time. However, it does cause 'light-off' within 15-30 seconds for most circumstances. I could not see this method being practical for a production vehicle (at least for the US market).

Honda made the decision to greatly compromise the MPG and potential for performance with this engine when they decided to enable quick cat function without the need for additional enrichment. This was a decision that they felt was important, and I don't fault them for it, nor do I fault any decision made in favor of reduced environmental impact over BSFC. The insight seems like a project where they wanted to try as many new ideas as possible all in one car, which I think is great. I just personally choose to have an extra 20-30bhp and an extra 10-15+mpg (very conservative on both figures).

I believe this modification will make the engine capable of reduced HC emissions over a stock Insight, at the trade of additional NO emissions.

However, the purpose of the modification is to get the engine to have an IMP:EMP ratio better than an extremely poor 1:1.5. This much improved exhaust/intake pressure ratio will enable the engine to make use of additional lift and duration, which will better locate the powerband of the engine towards my goals/pleasure. Also, it seems a shame to have such an amazingly solid racing type valvetrain and not take advantage of it :)

As far as the CRX talk goes, I have a Honda b20b CRV block which uses a honda b16a head and very high compression. It makes 215whp (sae corrected on dynojet), and it's setup with the non-vtec maps all made to lean burn at roughly 19:1 (the limit of my WBO2's top range, and hence the limit of my tuning). The car often achieves over 50mpg if I drive it with fuel conservation mind, much much less if I drive it in a way that puts a smile across my face :)

I have confidence that the Insight engine and platform will show excellent potential for economy and performance both once a few critical design trades honda made are traded back. I see no reason why compression increase, proper extractors, BSFC optimized cam profile and intake manifolding wouldn't result in a 100bhp 100mpg drivetrain that delivers much more driver pleasure as it sips its fuel.

Best Wishes,
-Luke

BTW- When thinking about any engine modification, you must keep in mind that engines are a system of compromises. No change can be made which does not impact all areas of the system. Some modifications combine to yeild more than the sum of there parts, some do not.
 

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liveforphysics said:
I see no reason why compression increase, proper extractors, BSFC optimized cam profile and intake manifolding wouldn't result in a 100bhp 100mpg drivetrain that delivers much more driver pleasure as it sips its fuel.
If you can pull it off AND be street legal then Microsoft's gonna be looking for another power systems engineer if you patent and market your achievements.

And I'll be one of your products owners.

Good luck :!: :)
 

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Discussion Starter #16
I am looking to aquire an Insight engine from a wrecking yard in WA for $350 if I can get enough time off work to pick it up on tuesday.

The same day I get it, I will keep you posted with what the cylinder head looks like sans-integrated manifold. :D I get projects done quickly, so hopefully I wont keep you waiting for long :D
 

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Are you by any chance trying for the X-prize? One could hardly ask for a better starting platform. ;) I'd say go for it. :D
 

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Insightful Trekker said:
If you can pull it off AND be street legal then Microsoft's gonna be looking for another power systems engineer if you patent and market your achievements.

And I'll be one of your products owners.

Good luck :!: :)
Agreed, very interesting ideas and thread. We await developments with baited breath :p
 

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Off topic a little , But I am interested in the "The non vtec" maps in your B20Vtec to achieve lean burn, yet still make power. WHat are you using to tune with ?
 

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Luke, another benefit of your proposed header mod is allowing the use of an aftermarket cat instead of the stock unit. The factory cat can run $1200 or more and there's no aftermarket unit since the total number of Insights produced is too small to interest manufacturers.

I think you can tell from the posts so far that if you were to offer a modified head, cam and header to the forum members, there's a lot of interest.

-John
 
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