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How light can the JH be?  Rating:  Rating
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 Posted: 09-10-2005 04:30 pm
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themagicalswitch
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I was just wondering to myself what my purposes for building this JH are. On the top of that list appeared weight, more specifically power/weight.

So I think I'll start a list and see if you guys would help me add to it as key weight savings areas.

-In most recent memory is the aluminum fuel tank.
-I thought of aluminum bodywork, but I'd need help with that so a ? for that.
-If I used carbon fiber what would you guys think of that. I could make a lot of the interior pieces in carbon - then paint over them probably. Also the lower air dam and headlight bezels could be carbon.
-What do you think weighs more - the soft top and frame, or a permanent top made from aluminum?
-Removal of all useless items ie. shrouds, guards, etc...
-Smaller or at least lighter battery.
-Probably lose some weight on the exhaust system
-Wheels/ tires - I'd imagine some pounds could be saved there
-Get rid of the emissions equipment.

Alright, please add anything you can think of (realistic or not) to this list.

Anthony

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 Posted: 09-10-2005 11:07 pm
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Greg Fletcher
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I don't see much of a point for all this- what is the goal? Just shaving off a few pounds for a road car seems like an expensive exersize that provides little return for your efforts. Your money might be better spent on a good quality paint job and upholstery. In the weight game, it's not just total weight but where that weight is distributed. A 50 pound bag of sand in the trunk of a stock Jensen Healey totally transforms the handling.

This reminds me of Clubber Bruce Blank, who had a custom carbon fiber drive shaft made for his JH. He freely admited it provided no real value, it just sounded cool and he worked for a place that was able to take on this project for a minmal cost. He said it would normally run $600 to get one made.

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 Posted: 09-11-2005 12:00 am
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themagicalswitch
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What is the goal? Well, basically losing a significant amount of weight will totally transform the car. Do you think that taking 100-200 lbs of weight or even more off of the car would add no value? That is just like adding power via 2.2L kits and all that other jazz, but the engine could remain the same.

Except this will enable you to brake and accelerate quicker through the lesser amount of weight being pulled around less rotational mass as I would use lighter cross drilled rotors, turn the flywheel down, etc...

In addition if the car were X-hundred pounds lighter with the 2.2L, Dellortos, etc. don't you think that would be a fun car? Now that would be a sports car.

As far as money goes - I'm not on some budget here, but besides that it wouldn't take much to do the things listed (unless the aluminum body was made) as I would do all the work myself, and in the case of the aluminum - with the help of a friend. Aluminum is kind of expensive, but carbon, resin, and mold release aren't. Neither are the materials to make the mold.

I guess this crew just isn't into this mode of thought, maybe because it is a "classic" car and it is supposed to be how it was designed. Well I owned a totally restored JH that was similar to the original spec and I can say it was a cool car, but there are tons of improvements to be made.

I'm also from the motorcycle building world where ounces matter. So I guess that is where this fascination comes form.


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 Posted: 09-11-2005 01:53 am
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Mark Rosenbaum
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I'm not a structural engineer but did study the field many decades ago.  I greatly doubt you could cut much weight from the frame, front crossmember, etc., and still have a safe, reliable car.  Presuming you want to remain street legal, you can remove a fair amount of weight if you don't mind ending up with a car that has, at best, primitive creature comforts.

Here's a list of things you could do along with some very poor guesses as to weights:
12# - Remove passenger's seat
11# - Remove heater box, heater fan, ducting, ball vents, defrost vents
  6# - Replace heater area structural plate with aluminum equivalent
25# - Carpets, floormats, padding, upholstery
  6# - Flywheel lightening
  1# - Remove carbon canister, hoses, fuel tank to canister pipe
  8# - Replicate front and rear suspension arms in aluminum
  2# - Lighten road wheels
  7# - Replace 2nd muffler in exhaust system with a pipe
25# - Replace front & rear bumpers with dinky little bits
  1# - Remove timing belt shroud
  1# - Replicate rear motor mount in aluminum
  1# - Replicate rear stiffener (driveshaft catch loop) in aluminum
  2# - Remove side marker lights
----
108# - total weight removed (remember, this is a poor guess)

This is about a 5% decrease in weight, and accleration, brake stress, and cornering would all improve by a somewhat similar percentage.  If you were also to add 7 HP to the engine, acceleration might improve to 10% total.  Is it worth it?  Only you can decide.

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 Posted: 09-11-2005 02:08 pm
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Dave
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I'm with you on this. If you've got the access to facilities to make carbon fiber replacements everyone should be all over this. One, it's always good to have access to replacements, and to have lightweight, strong, non-rusting replacements is even better. These things are hobbies, which means by definition they don't make a lot of sense, the idea is fun.

Body panels, door skins (inside and out) and the hood would be my recomendations. The aluminum fuel tank is already available aka some of the fuel cells out there. Let us all know if you're going forward with any of these ideas, I could be interested in some of these parts! In carbon or fiberglass, two,or three, is almost as cheap as one.

Dave

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 Posted: 09-11-2005 02:53 pm
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Joel
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I agree within reason. If you had a good supply of like fiber replacements (airdam etc)that didn't look horrible I'd be interested.

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 Posted: 09-11-2005 05:05 pm
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SportsRodder
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The Jensen Healey is very light compared to most production sports cars. There are two reasons for removing weight, one to improve the power to weight ratio and two to improve the weight distribution.  Power to weight ratio is more easily improved by increasing horsepower which many owners have done by upgrading  to  the 2.2 engine and other engine improvements.  Weight distribution improvements would involve removing weight only from the front as removing weight from the rear would result in poor handling.  Later model 74's and 75's could lose significant weight by replacing the 5 mph bumper with the earlier and lighter '73 unit.  An aluminum or carbon fiber hood  front fenders would also be desirable, though expensive.  Light weight wheels are available but not in JH bolt pattern and size.  An aluminum radiator might lose a few pounds if one could be found in the right size.

Lighter is good however I think you will find the dollar to weight ratio will increase signicantly.

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 Posted: 09-11-2005 06:58 pm
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Greg Fletcher
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OK, Magicalswitch- I guess I'm just in classic mode. I see the "money is no object-it's my hobby-why should should it make sense?" thing going on. I don't have any issue with that, but spending a few thousand adding a 2.2 engine is one thing and reskinning the body in aluminum is quite another, certainly not in the realm of most of us mere mortals. The Jensen Healey is a fun car to start with, it is a sports car, a vintage one to be sure. How much more fun less weight would add on the JH is what I'm not sure about. I think it would great to see someone try this and report their results (perhaps even a newsletter article?), and let us know.

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 Posted: 09-12-2005 01:21 am
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Judson Manning
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I'll let everyone know how much the new car ends up weighing whenever I get around to finishing my E-prod project....but then again, I have a minimum weight to maintain of 2,090lbs. 

Strange....in Solo I street legal trim (full interior, spare tire, roll-bar, etc.) the car weighed 2,150lbs on the scales at Roebling...

BTW, not much to be saved in the wheel dept (I think stock wheels are a magnesium alloy).  My 13x6 Panasports that now live on Ron's car actually weighed a heck of a lot more w/ BFG R1s than the stock wheels w/ Yok AVS.

 

Last edited on 09-12-2005 01:29 am by Judson Manning

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 Posted: 09-12-2005 01:41 am
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themagicalswitch
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Judson Manning wrote:


BTW, not much to be saved in the wheel dept (I think stock wheels are a magnesium alloy).  My 13x6 Panasports that now live on Ron's car actually weighed a heck of a lot more w/ BFG R1s than the stock wheels w/ Yok AVS.

 


That is surprising. Let us know about those numbers.

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 Posted: 09-12-2005 10:34 am
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Harkes
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MagicalSwitch: i missed an item on the list that can reduce weight whilst improve performance....

While awaiting my 2.2L engine to come over i have done numerous upgrades to the car. I was quite shocked when i had one of the front brake calipers disassembled. It weighs a hell of a lot. With the increased horsepower, i was looking for performance brakes and bought the JenSport Big Brake.. the four pot brakes are F1 quality in terms of performance and WEIGHT!! it weighs  roughly 70% less than the stock brake calipers! Great weight savings there.

Good luck with your project. Do list photos on the http://www.jhppg.com if you will, so we can follow your progress!

Erik, Netherlands

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 Posted: 09-12-2005 10:09 pm
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pc
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The traditional answer to your question is not an answer but another question.

Q: How light can the JH be?

A: How much money do you have to spend?

If you've got the bucks you can acid dip the shell, replace body panels with aluminum and composites, replace stamped structural elements with welded tubular chrome-moly, use titanium fasteners and fab up all manner of replacement pieces from machined billets.

As long as you have a McLaren budget...


PC.

Last edited on 09-12-2005 10:09 pm by pc

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 Posted: 09-21-2005 02:53 am
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themagicalswitch
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I got a call today from the guy making the Aluminum tanks. He and I talked about him using my body pieces to make the tooling to do bonnets, fenders, etc.. out of aluminum, or steel for that matter.

He and I are going to discuss more via email in the next couple of months and hopefully get started in Nov. if prices are reasonable. He seems really excited to be doing stuff for the Jensen so he may be a valuable asset to out community.

----------------

Good info Harkes - I was planning on those to begin with so I guess now it will have to be that way.

pc - hum. McLaren no, so that takes away anything Ti as well as a custom frame - although that would be cool. But you can make amazing cars without huge dollars. Look at this car, it's 0-100 is 6.31 and the Ferrari Enzo is 6.3. Oh this car is less than 1/10 the price I saw an Enzo sell for in Monterey last month.



This Ultima GTR is even cheaper and it is 0-100 in 6.8, 0-60 in 3.3

Last edited on 09-21-2005 02:57 am by themagicalswitch

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 Posted: 09-24-2005 03:03 am
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pc
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You asked how light a Jensen Healey could be, not how light a Jensen Healey could be made within $xyz budget.

I’m not knockin’ your idea. Quite the contrary, I love the idea of a stripped down JH “SL”. I just believe that any project has constraints and the key to success is balancing your choices.

There’s a lot more to the cost of an Enzo than power to weight ratio. Ferrari had their own set of parameters in mind when they made their engineering trade-offs. Then there’s the price people are willing to pay, an entirely different subject. Apples and oranges.

And speaking of apples and oranges, pricing on that Stealth B6 starts at £98,500 (US$175k). The Ultima GTR starts at a rather more comfortable US$89k, but then you need to come up with your own engine and transaxle (and install them yourself).

If I were looking for such things I would also consider a Noble M400, only US$66,900 without motor and trans. You’d be on the road for less well than $100k.

If quick (as opposed to fast) for the buck is the goal you can’t beat going light. The best acceleration/$ dollar is going to be a bike but for a four wheeler the coolest thing I’ve seen so far is this little number,

The Atom. Caught it on Top Gear Wednesday night. The quickest thing they’ve ever tested and faster around their track than all but the Enzo. An absolute steal at £35,000 (US$62k).

From a cost perspective all these cars have something else in common, they’re produced in quanities. Small quantities to be sure, but large enough to amortize fabrication tooling and development costs over multiple units. Our hypothetical JH SL won’t (unless we all build them, which would be fun).


PC.

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 Posted: 09-24-2005 03:54 am
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themagicalswitch
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You know as for money vs. power, that new Z06 Corvette is ridiculous. I really am not a fan of Chevrolet of the Corvette, but jeez, what a deal!

I heard that it was at some track in Germany and was putting in some of the fastest laps ever, only a handful of other cars were faster. I bet non of them were under $60K.

To me it just doesn't look good, and that is a major problem.

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 Posted: 09-24-2005 04:08 am
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themagicalswitch
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Oh, I was also going to say that the Noble is a cool car. I drove one about a month ago. There is a dealer in Carmel, IN, which is about 45min. from me, that sells them.

http://www.ooley-blackburn.com/inventory.asp

One of my friends wanted one so we took it for a test drive. Fun! He got the M400.

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 Posted: 10-13-2005 06:06 pm
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DanHolmes
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Carbon fibre is always the material of choice if weight is the key however in order to do it properly you must be prepared for some outlay in terms of vacuum bagging and ovens.

I work in advanced composites and have mulled over the idea of making carbon fibre bonnets (hoods) for the JH since mine is very heavy and the double skin promotes rust on the leading edge - the weight savings (if I could get it right) are enormous!

Secondly and perhaps a little easier is to replace the prop shaft with a carbon fibre tube. These are made to very high specs using a process called filament winding - I suspect that an good automotive/race engineer could figure out how to attach the UJ's relatively easily if you could supply dimensions and specify a wall thickness from torque calculations.

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