Living with the Mid Engined Spitfire
Unlike a standard car many of the parts on my Spitfire are custom made or stolen from another car manufacturer, so inevitably things need fixing, changing or tweaking. I guess my little car will never truly be finished.
15th September 2021
I didn’t see that coming!
I pulled out of my drive and heard this rattle coming from the engine, then it died. I tried to start it but nothing. So I pushed it back into the garage. Timing belt Ok, nothing electrical, a quick compression test showed nothing, zero compression on any cylinder.
I took the head off and saw 12 of my 20 valved were all smashed, and every piston and a small gash from the centre inlet valve. So, all 8 exhaust valves and 4 of the inlet valves were bent.. But the timing belt was perfect, maybe it had slipped, but why?
I pulled the lower cambelt cover off and saw a 1 inch square piece of 1/8 inch plastic wedged between the belt and the pulley.
That’ll be the reason then. So I have now acquired a new head, a big port AGU head, this has inlet ports that are twice the size of my AWT’s head. I’ve stripped it down, and transferred teh VVT (variable valve timing) over to the new head.. But wait..
I have ordered my new parts from AUTODOC, and it will takes weeks for them to come from Germany, So I have decided to rebuild the engine. I have ordered some new BAM pistons and Maxspeeding forged conrods. This will allow me to increase the power of the engine from its current max of 300 bhp so 500 bhp plus..
Just need to wait for all my bits to come..
15th August 2021
This weekend I finished fitting the anti roll bar. I welded 2 bits of 40mmx40mmx5mm angle to the existing Audi A4 B7 anti roll bar mounts. The TT roll bar now fits like its was designed to be there.. Wow, what a fit!
The car drives so much better now, the rear feels less bouncy and much more stable, not just in the corners but also on the straights. Obviously I have lost all my rear body roll, so the car feels really planted and squat when cornering. I still get some tyre rub on the wheel arches, but short of fitting longer springs or re-designing the rear arches, there is not much I can do about that.
On a roll, i also fitted a secondary electric coolant pump, again from a scrapped Audi TT. On the TT this little pump stays on after switching the engine off and pumps coolant to cool the turbo, on my car, it pumps coolant round the car’s heater matrix. As the car engine is in the back, the engine’s water pump isn’t quite man enough to pump round the radiator AND the heater.
The pump was broken when I got it, I machined a new pump housing and a friend TIG welded 2 aluminium pipe fittings to it.
11th August 2021
Over the weekend we scrapped a 1999 Audi TT, removing most of the bits that might be useful at a later point. My eldest son, Dominic suggested we try and fit the rear anti roll bar to the back of the Spitfire.. I have tried various ARBs before, but none fit due to the gearbox being in the way.
Yesterday, I gave it a go. The first steps was to mount the ARB drop links, this meant drilling and tapping the lower suspension links. Surprisingly the ARB fitted perfectly, almost made to measure. One last job, I have to extend the chassis anchor points, then we should be good to go. I have ordered some 40x40x5mm angle steel, which will hopefully be here for Saturday.
So its now August 2021.. I’ve done about 500 miles in my little car. So much has changed since I first legally drove it in December 2020.
I now have a limited slip differential, the car makes so much power that the back wheels would spin changing up the gears. Now I have so much traction. Coupled with my new gearbox, the Spitfire will accelerate from 0-60 mph in 3 seconds and just keeps accelerating. I also have Meth/Water injection. This keeps the charged air ice cold and dense as it is ingested by the 20v 1.8t engine. Dense cold air means more power! its not like NOS, but certainly has a drastic effect.
The front and rear shock absorbers have been replaced, I still need to change the springs to make the car less jittery on a rough surface, but man, put your foot down in any gear and this little car is like a rocket. Certainly the fastest car I have ever driven, and I am not sure there is much on the road that would keep up with it..
I have nice Oz racing black alloys, they look really cool, staggered to wide rears to match the 225/50r17 rear tyres.
So I continue to drive my little car, it puts a great big smile on everyone’s face (apart from Spitfire owners 🙂 )
13th May 2021
So much has happened to my little car, not all great 🙁
The Limited Slip Differential has now been fitted, It wasn’t the easiest job, but I got it in, which is all that matters. It has transformed the way the car drives, no more wheel spinning while accelerating up through the gears, it feels properly planted now.
I did buy a Quaiffe LSD, but it didn’t fit! The drive shaft flanges were too “fat” to fit in the differential, In the end I went for a plate LSD, which cost £20 on ebay! it consists of 2 hard steel/iron plates with 4 very powerful springs in between. I had to grind down the edges by 2mm as it was slightly too wide to fit in. But it fitted..
The next BIG job was to sort out the front steering once and for all. I have now made custom hubs, these are basically standard Triumph hubs welded to Audi A4 hubs.. or rather the 5 bolt flange part of the Audi hubs. This has allowed me to use Audi brake discs. To use my BMW calipers I had to make aluminium adapters.. I have also raised the steering 2″, To do this i made a 2″ thick box frame that is welded to the chassis, below the steering rack and suspension turrets. This allowed my to fit shorter springs, lower the car at the front and maintain an OEM steering geometry.
I also have some new wheels on the car, gone are those Fox alloys, I now have MSW by Oz Racing alloys. Staggered, 8.5″x17 on the rear and 7.5″x17 on the front. I went for 225/45r17 rear and 205/40r17 on the front. This means from a tyre size my back ones are correct to keep the speedometer correct.
Driving the car is fun, it is very very fast, I had a new high boost map added, the car produced so much boost it blew the intercooler to bits! unfortunately this also did some body damage 🙁
The one thing we did learn from driving it, especially on long runs, it needed sounds!
So I have now fitted as Pioneer bluetooth head unit and 400w amplifier along with matching Pioneer speakers..
As I said driving the car is a blast, it hits 80 plus mph really quickly, pulling almost .6g acceleration, which as I understand is quite good for a road car.
So What as of the 27th January 2021 needs doing?
New wheels – they are on my shopping list. The current Fox alloy wheels are nice but.. one of the rear wheels is not very round, they are also drilled for BMW hubs, i.e. 5×120. The rear hubs are Audi, 5×112 so I had to slot the wheels to make them fit.
So I want to replace them with a staggered look, 8″ x 17″ rear wheels with Audi PCD and the front 7.5 or 7″ x 17″ BMW PCD
Limited Slip Differential
The car has an open differential, that means only the rear left wheel drives the car. So when the rear wheels spin, only one moves, this makes the back of car very unstable as it spins them in all gears if I am too hard on the throttle.
I have bought a universal LSD, however I don’t want to fit it into my gearbox, just in case it ruins it, so I am going to buy another Audi diff to work on. This is a job for the summer
Front wheel Geometry
I think when I made the front hubs I made a mistake, as the steering is very similar to a shopping trolley. So the most pressing and urgent job for this weekend it to sort that out.
Today I sorted out the front geometry, well the tracking (wheel alignment) and caster anyway. The caster was neutral which meant the steering was horrible. I had meant to add 3 degrees caster, instead I added 3mm caster, so the car handled like a shopping trolley. the 3 degrees is the angle from the wheel pivot to where the lower balljoint connects to the hub. I was advised that 5 Degrees would be better, and 5 degrees on my uprights is 9mm from the centre line..
To set the tracking I went old school and made a jig.. 72″ pieces of wood bolted to the front and rear centre lines with string running parallel the length of the car. Then it is just a simple job of using a tape measure and adjusting the tracking. I set the alignment to 2 mm tow in.
I have also replaced the rear springs with some longer and stiffer ones. This has raised the rear slightly giving me more room on the rear arches.
Now the car drives in a straight line and the steering feels epic!