Home 
Home Search search Menu menu Not logged in - Login | Register
> Jensen Healey & Jensen GT Tech > Miscellaneous > How light can the JH be?

 Moderated by: Greg Fletcher
New Topic Reply Printer Friendly
How light can the JH be?  Rating:  Rating
AuthorPost
 Posted: 09-10-2005 03:30 pm
  PM Quote Reply
1st Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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

Back To Top PM Quote Reply  

 Posted: 09-10-2005 10:07 pm
  PM Quote Reply
2nd Post
Greg Fletcher
Administrator


Joined: 03-11-2005
Location: Lake Nacimiento, California USA
Posts: 430
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-10-2005 11:00 pm
  PM Quote Reply
3rd Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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.


Back To Top PM Quote Reply  

 Posted: 09-11-2005 12:53 am
  PM Quote Reply
4th Post
Mark Rosenbaum
Member


Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-11-2005 01:08 pm
  PM Quote Reply
5th Post
Dave
Member
 

Joined: 03-12-2005
Location: Lutherville, Maryland USA
Posts: 17
Status: 
Offline
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

Back To Top PM Quote Reply  

 Posted: 09-11-2005 01:53 pm
  PM Quote Reply
6th Post
Joel
Member
 

Joined: 07-01-2005
Location: San Diego, USA
Posts: 184
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-11-2005 04:05 pm
  PM Quote Reply
7th Post
SportsRodder
Member
 

Joined: 03-25-2005
Location: San Dimas, California USA
Posts: 27
Status: 
Offline
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.

Back To Top PM Quote Reply  

 Posted: 09-11-2005 05:58 pm
  PM Quote Reply
8th Post
Greg Fletcher
Administrator


Joined: 03-11-2005
Location: Lake Nacimiento, California USA
Posts: 430
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-12-2005 12:21 am
  PM Quote Reply
9th Post
Judson Manning
Member


Joined: 03-14-2005
Location: Atlanta, Georgia USA
Posts: 406
Status: 
Offline
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 12:29 am by Judson Manning

Back To Top PM Quote Reply  

 Posted: 09-12-2005 12:41 am
  PM Quote Reply
10th Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-12-2005 09:34 am
  PM Quote Reply
11th Post
Harkes
Member


Joined: 03-17-2005
Location: Warmond, Netherlands
Posts: 216
Status: 
Offline
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

Back To Top PM Quote Reply  

 Posted: 09-12-2005 09:09 pm
  PM Quote Reply
12th Post
pc
Member
 

Joined: 03-16-2005
Location:  
Posts: 58
Status: 
Offline
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 09:09 pm by pc

Back To Top PM Quote Reply

 Posted: 09-21-2005 01:53 am
  PM Quote Reply
13th Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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 01:57 am by themagicalswitch

Back To Top PM Quote Reply  

 Posted: 09-24-2005 02:03 am
  PM Quote Reply
14th Post
pc
Member
 

Joined: 03-16-2005
Location:  
Posts: 58
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 09-24-2005 02:54 am
  PM Quote Reply
15th Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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.

Back To Top PM Quote Reply  

 Posted: 09-24-2005 03:08 am
  PM Quote Reply
16th Post
themagicalswitch
Member


Joined: 03-14-2005
Location: Bloomington, Indiana USA
Posts: 22
Status: 
Offline
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.

Back To Top PM Quote Reply

 Posted: 10-13-2005 05:06 pm
  PM Quote Reply
17th Post
DanHolmes
Member
 

Joined: 10-12-2005
Location: United Kingdom
Posts: 9
Status: 
Offline
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.

Back To Top PM Quote Reply  

Current time is 02:00 pm  
> Jensen Healey & Jensen GT Tech > Miscellaneous > How light can the JH be? Top




UltraBB 1.172 Copyright © 2007-2011 Data 1 Systems