my turbo'd spitfire

[UncleBob]

Continuing my long tradition of turbo projects for the few that are interested in this kind of crazy stuff, I have a new project!

I'm a bit of a bike-oriented type of guy, and this is no different.

I'm not just turbo'ing a car....nothing so mundane as that! No sir.....I'm going to install a motorcycle engine in a car, and THEN turbo it

The car in question, a sweet little deal I ran into, a 1974 Triumph Spitfire. Why? Well, its light, it grandfathers the emission laws in my state, and its got some cool-factor (IMO). I also got it for a steal, which helped the decision

I picked up a ZRX1100 motor (of course) to shove in there, and plan on making around 300 ponies when I'm done. This should make it a decently fun ride. Stock weight for these cars is around 1700 pounds, but thats with an all-iron engine/tranny, so I should shed about 150 pounds of weight with this modification, making for a pretty decent power to weight ratio

why a ZRX1100 motor? Well, not only am I very intimate with them, especially when turbo's are involved.....they are simply cheap as hell to pick up. I got a motor for it for barely more than the cost of shipping it. They have a lot of potential since they are basically a side draft version of a zX11. I could have make a lot more power out of a busa engine or ZX14 engine, but it would have been a lot more expensive. Another nice advantage of the ZRX/ZX11 engines, they have a huge aftermarket support, including being used for sprint/legend cars, which is similar aspects to what I'm doing here

These cars are known for having pretty good handling, and I won't be removing that aspect

Just to answer some pre-assumed questions: it will use a jack-shaft-like setup to change the gearing (which was needed because if I drove it directly off the output shaft, it would top out around 110mph), and run off the stock rearend/driveshaft. It will have reverse, with a cute little setup I'm devising. I will probably eventually update/change out the rear end setup for a more modern, better handling, posi-capable such as out of a miata....although that will take a bit of fabrication due to the frame configuration. But thats long down the road.

I'll add updates later.

Talk amongst yourselves

Pic of the car:



after removing the engine and tranny, and cleaning up the engine compartment....a lower engine case half out of a ZRX for mocking purposes, roughly where the engine will end up:

[curtis73]

How are you going to prevent facial cramps from the perma-smile you'll get at 10,000 rpms ?

[Greenblurr93]

surgery... cool project.. good luck (psst... fix that rust!)

[antzbongo]

mate thats bloody awesome! we need more people like you. everyone always does same old shit thats been done 10000 times before. great stuff!!!!

[KiwiBacon]

Very interesting. They're a very cool little car and could do with an engine update.

Do you think you'll have any cooling issues?

[UncleBob]

Originally Posted by KiwiBacon

Do you think you'll have any cooling issues?

not when I get done with it....I wont be using the stock radiator

[UncleBob]

Originally Posted by curtis73

How are you going to prevent facial cramps from the perma-smile you'll get at 10,000 rpms ?

11K RPM's, and yes, I'll have trouble with that

[Moppie]

HAHAHHAHAHAHHAHAHHAAA!!!!!



Good luck making it go around corners with 300hp driving through that abortion of a back end!


And please, get rid of those fugly rubber bumpers.

[UncleBob]

Originally Posted by Moppie

HAHAHHAHAHAHHAHAHHAAA!!!!!



Good luck making it go around corners with 300hp driving through that abortion of a back end!


And please, get rid of those fugly rubber bumpers.

incase you didn't read the entire post:

"I will probably eventually update/change out the rear end setup for a more modern, better handling, posi-capable such as out of a miata..."

and yes, I plan on ditching those

[Moppie]

Originally Posted by UncleBob

incase you didn't read the entire post:

"I will probably eventually update/change out the rear end setup for a more modern, better handling, posi-capable such as out of a miata..."

and yes, I plan on ditching those

Oh I read it, but I also used to own a kit car that used a Triumph Herald Chassis, which is exactly the same as the Spitfire Chassis.
It had couldn't handle 100hp from a 2TGE, I know it won't handle 300

There are ways of improving the Swing Axle design, the later Spitfires all had an extra linkage in the bottom, making a sort of double wishbone set up, where the axle formed the upper link.
The same set up was used on the MKII GT6.
It works quite well at stopping the swing arms carrying into negative camber just when you don't want them to, but it puts a lot of stress, on the already stressed rubber CV's in the axles (which are becoming harder to get new).

There is however lots of room for a Datsun/Nissan/Subaru 180B/180sx/200sx/240sx/WRX rear diff, which gives all sorts of options for LCD set ups (fluid, mechanical, and adjustable). Its a Fuji Heavy industries unit, and is VERY strong.

The Transverse Leaf in the rear suspension can also be tightened up quite easily, but you need to match it with the right shocks or it suffers sever axle tramp.


I had worked out a plan to fit the rear suspension from a Mazda Familia BF AWD Turbo, and use a Datsun 180B LSD.

[UncleBob]

Originally Posted by Moppie

Oh I read it, but I also used to own a kit car that used a Triumph Herald Chassis, which is exactly the same as the Spitfire Chassis.
It had couldn't handle 100hp from a 2TGE, I know it won't handle 300
LSD.

exactly why I'm not keeping the stock rear end setup

You say you read it, yet then you go on about how bad the stock rear end is, when I specifically said, I'm not going to use the stock rear end.

I have looked into the WRX rear end, among others. So far I like the miata setup best (don't know if you have that in your country) because of its total width, and height-friendliness....and its aftermarket support.

The WRX is a little more comlicated, taller, and wider. Not quite as friendly to this application

Either way, this will require a bit of fabrication to work, with the under-slung X frame setup that the spitfire uses

[Moppie]

Not finished yet, just had to check on dinner.


The Front suspension however is FANTASTIC!
It formed the basis of the orginal Lotus 7, and the uprights with upper ball joint was used in a number of different Lotus cars, most importantly all the 4 cylinder Esprit models.
Its a very simple design, and has lots of room to add different brake set ups, wheel hubs, etc.
Common conversions are Ford Transit van from discs on Cortina hubs (probably hard to get those bits in the states) and BMW 2002 discs over the triumph Hubs with after market calipers on a custom made brackets.
You can also retrofit the brakes from the large 4dr Toledo, and better yet the 2500TC. Although both sold in very small numbers in the US.



The Chassis itself can also be a weak point.
On the early Lynx Twincam Kit cars (of which 50 were made here in NZ) they used the standard chassis, which bows out after the rear engine mount.
On my car, the rails were seperated, turned over, and welded back onto the cross members.
This means they bowed in, and were apprently a lot more rigid.
You don't want the body popping off when you open it up

[Moppie]

Originally Posted by UncleBob

exactly why I'm not keeping the stock rear end setup

You say you read it, yet then you go on about how bad the stock rear end is, when I specifically said, I'm not going to use the stock rear end.

I have looked into the WRX rear end, among others. So far I like the miata setup best (don't know if you have that in your country) because of its total width, and height-friendliness....and its aftermarket support.

The WRX is a little more comlicated, taller, and wider. Not quite as friendly to this application

Either way, this will require a bit of fabrication to work, with the under-slung X frame setup that the spitfire uses

Hey, I'm not digging at ya, I know you will make it work.
I just got the feeling replacing the rear end was going to happen sometime after the car got its new motor and was back on the road


We do get lots of MX5's here. They were very popular in Japan.
Its another popular donor for rear ends, I actualy looked into it, but the diff head is quite large compared to the Fuji unit, and was a lot more expensive here.

The Fuji unit is very slim, but a little long. Its found in all the cars I mentioned, and can be easily adapted to fit different axles.
So you use it with other suspension set ups, or even design your own useing others parts.
This is why I wanted to go with the Mazda set up, as it was a easy to alter multi link arrangement.
I could also make it work with the transverse leaf spring, which was important as there was no where to mount normal springs or struts on the kit car.

[Moppie]

crap, now there is toasted sandwhich filling all over the bench.
Ah, a cold beer will help

[UncleBob]

I will get the car rolling first with the stock rearend. But it will only be making 110hp and 65ft/lb's. Far from mind-blowing power output. I won't turbo it until I change out the rear end. I'm using the naturally asperated engine as a testing bed for my different concepts, working out the details. Then I'll try playing with real power.