In reply to Racingsnake :
If the Ford rear end is 175 pounds ( I'm assuming that includes the brakes too?)
The Jaguar rear end parts that are needed would Likely weigh less than that. Plus the whole center section would be mounted to the chassis. Rather than adding to the sprung weight.
I'm guessing here but I think the parts that are sprung might be 35-40 pounds. Which would be much closer to the sprung parts of the original rear end.
Since the whole Ford rear end would be sprung that would take away a lot of the nimble feeling of the original Bug Eye. The heavier feeling would take away much of the go-cart feeling you get when driving the original Bug Eye Sprite.
So, I kept tossing around in my mind about doing a bike powered spridget for track days.
What about a quick change out of a Baby Grand? I mean they come in 60" width, but with their ability to be offset it looks like you could shorten one.
In reply to frenchyd :
If the 175# came from me, it was for an 8.8" with disk brakes. Someone on the web said that the difference between the 7.5 and 8.8 was negligible.
newrider3 said:
bumpsteer said:
they typically use the same wheel bearing setups as their 8.8 brethren so 8.8 c clip eliminators should work
Avoid c-clip eliminators for anything outside drag racing. We tried them on the Ford 7.5 in our (very light) Starlet and they leaked gear oil everywhere and ate the bearings after only a handful of road course laps.
We ended up switching the housing ends to Moser units to use "small" Ford 9" bearings on custom axle shafts. We really only had to go to all the trouble because we accidentally narrowed the housing too far though.
This is very good to know! What brand did you use? I've been looking at Strange because they offer integrated 13/14 GT500 caliper brackets which will allow me to get rid of the adapters I currently have in order to run 14" rear rotors.
In reply to VolvoHeretic :
To be fair I should grab the pieces and parts needed and actually weigh them rather than trying to use my memory.
We are busy putting a fireplace in the house. So it would require a lot of tunneling and digging to get to them.
I've carried MG and Morris Minor rear ends. I think there is about 20+ pounds difference. They would be an inch maybe 2 wider than a sprite.
The cage for a Jag sedan is about 70- 80 pounds and that wouldn't be used. Plus the drag links seem to be 25-30 pounds each and they wouldn't be used. The "Dog Bones". (Axles) probably are 10-12 pounds each. But shorter driveshafts are probably lighter.
When I narrowed a pair of lower control arms. I'm thinking they were 12-15 pounds each. Hubs 25-30 each?
Stock bolt circle is 5X 4&3/4 (Chevy)
In reply to bumpsteer :
Strange is what we tried, you can see the saga when we tried to race on them here:
https://grassrootsmotorsports.com/forum/build-projects-and-project-cars/1983-toyota-starlet-h27a-v6-swap/163295/page3/
frenchyd said:
In reply to Racingsnake :
If the Ford rear end is 175 pounds ( I'm assuming that includes the brakes too?)
The Jaguar rear end parts that are needed would Likely weigh less than that. Plus the whole center section would be mounted to the chassis. Rather than adding to the sprung weight.
I'm guessing here but I think the parts that are sprung might be 35-40 pounds. Which would be much closer to the sprung parts of the original rear end.
Since the whole Ford rear end would be sprung that would take away a lot of the nimble feeling of the original Bug Eye. The heavier feeling would take away much of the go-cart feeling you get when driving the original Bug Eye Sprite.
The Jag rearend is very compact to fit in the chassis but it is not really all that light and it has some significant geometrical issues compared to a simple 4 linked solid axle with a low mounted Panhard rod.
I know you like 'em but starting from scratch, it is amazing how much weight is saved when the brakes are just attached to a 2.5" piece of tube. Or in the case of a dropout style rear like a Mazda or Toyota or an older Ford, a couple stamped pieces of sheetmetal. No uprights, no subframe or other superstructure for attaching the diff. Just links to the frame or body as the case may be.
This is a lot of why cars used to just have a stick axle on leaf springs. Less metal means cheaper construction, also means less weight.
It occurs that I have a spare spridget rear end without brakes that I could weigh if there is enough interest to make me feel like grabbing it off the shelf.
They are light. Like, I can carry one by myself and transported one across the back seat of a Subaru Impreza before.
Apexcarver said:
It occurs that I have a spare spridget rear end without brakes that I could weigh if there is enough interest to make me feel like grabbing it off the shelf.
They are light. Like, I can carry one by myself and transported one across the back seat of a Subaru Impreza before.
If you've got time and nothing better to do it would be an interesting data point
In reply to frenchyd :
I'm pretty familiar with Jag suspension - I've had about 15 of them, have helped build hot rods with Jag rears and am currently helping a friend put Jag front and rear suspension on a Ford F1. I'm not interested in running one in the Sprite.
In reply to Pete. (l33t FS) :
The only advantage a straight axle has over an IRS is in drag racing the geometry is well known how to make it effective. Yet that same geometry is badly compromised during cornering.
Again with truck arm suspension cornering in one direction that geometry is well known. From experience with the circle track crowd. However when corners I. Both directions are involved those compromises put the straight axle at a disadvantage.
Formula cars, Can Am cars road race cars the ability to keep both tires flat on the ground is a real advantage.
Ferrari, Mercedes, Aston Martin, an IRS is the answer.
OK if you don't like Jag. Use a Datsun 240z, BMW, Lotus, Miata. Or whatever you prefer.
But any differential that will stand up to a small block. Even a mild one is going to be too heavy. So take the weight of the center section and mount it on the chassis. Now you have a shot at keeping a Bug Eye Sprite in character. Because the only thing moving around is light.
There is a very good book, Fred Puhn the Art of handling.
Pete. (l33t FS) said:
frenchyd said:
In reply to Racingsnake :
If the Ford rear end is 175 pounds ( I'm assuming that includes the brakes too?)
The Jaguar rear end parts that are needed would Likely weigh less than that. Plus the whole center section would be mounted to the chassis. Rather than adding to the sprung weight.
I'm guessing here but I think the parts that are sprung might be 35-40 pounds. Which would be much closer to the sprung parts of the original rear end.
Since the whole Ford rear end would be sprung that would take away a lot of the nimble feeling of the original Bug Eye. The heavier feeling would take away much of the go-cart feeling you get when driving the original Bug Eye Sprite.
The Jag rearend is very compact to fit in the chassis but it is not really all that light and it has some significant geometrical issues compared to a simple 4 linked solid axle with a low mounted Panhard rod.
I know you like 'em but starting from scratch, it is amazing how much weight is saved when the brakes are just attached to a 2.5" piece of tube. Or in the case of a dropout style rear like a Mazda or Toyota or an older Ford, a couple stamped pieces of sheetmetal. No uprights, no subframe or other superstructure for attaching the diff. Just links to the frame or body as the case may be.
This is a lot of why cars used to just have a stick axle on leaf springs. Less metal means cheaper construction, also means less weight.
The brakes aren't on the part that moves on a Jag they are inboard. Zero weight.
We aren't talking about is a Sprite a good suspension. It's fine. Within its limits. It won't survive the torque of a V8. The brakes won't stop the car. 13 inch wheels are too small to have enough brakes to stop 15" are called for. And while vented is better at least use disk brakes to deal with the heat.
The Sunbeam Tiger tried it with 13". The Chevy Monza (13") faded in just a brisk drive around the lake. Without even breaking the speed limit. In short you need a 12"disk up front and at least a disk brake in the rear
In reply to frenchyd :
A Lotus 7 used a live axle and seemed to do OK at road racing.
I've always read a live axle is better than a poorly designed IRS.
In reply to mblommel :
Yes and a lotus 7 had 13 inch wheels. Do you know what it didn't have?
A V8.
Oh, I don't know about Ferrari, Aston Martin, Mercedes etc.
but a Jaguar XKE does a nice job. So handling shouldn't be a problem.
frenchyd said:
In reply to mblommel :
Yes and a lotus 7 had 13 inch wheels. Do you know what it didn't have?
A V8.
Oh, I don't know about Ferrari, Aston Martin, Mercedes etc.
but a Jaguar XKE does a nice job. So handling shouldn't be a problem.
Suspension geometry is not dependent on wheel diameter.
Suspension geometry is not dependent on engine configuration.
A Ferrari 250 GTO won plenty of races with a live axle.
An Aston Martin DB5 runs a live axle.
What's your point?
You're so wrapped up in pushing every person on here to put old Jaguar parts on their project you can't see the forest for the trees. The Jag IRS has well known geometry and maintenance issues that make it much less desirable than a modern real double wishbone.
We used to have a guy in our local Miata club who also owned an E type and an air cooled 90's 911. He never drove the Jag. One time we asked why. His response: "It looks nice but it drives like an old pickup truck."
You're obviously knowledgeable but not doing yourself any favors with the condescending attitude and failure to take a hint. The OP straight up told you he's dealt with Jag IRS before and wants a stick axle. Can't you accept that and move on?
LOL ya'll letting old Frenchy draw ya'll in again.
mblommel said:
In reply to frenchyd :
A Lotus 7 used a live axle and seemed to do OK at road racing.
I've always read a live axle is better than a poorly designed IRS.
All successful front engined rear drive rally cars had live axles, and practically all used the same 24" long parallel 4 link setup...
In reply to mblommel :
I watch the Jaguar XKE race with Corvette 454's at tracks like Sebring , Elkhart Lake, Watkins Glen, Mid Ohio. etc. ( power tracks) that little old fashioned 258 cu in engine is there nipping at the heels of the Corvettes Occasionally popping to the front.
It tells me that you can have a lot of fun with old obsolete parts.
I've race a straight axle. My old Black Jack had a Halibrand quick change installed in the Jaguar straight axle.
I dealt with the limitations but with the DeMar which had IRS that wasn't a limitation.
As far as geometry conflict. It's not a conflict. It's a trade off. As you know race cars make horrible street cars. And street cars need work to make them Race cars. The "fix" on Jaguars is well known. And works on any IRS regardless the brand.
It's also the same geometry used by every Formula 1 car of the era.
Regarding the Ferrari and Aston Martin examples you used? Notice when they changed to IRS?
In fact looking at the rear suspension of most cars and SUV's of today, you no longer see that straight axle. Oh, big heavy pickups where load capacity is a priority? Sure.
