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Author: Subject: T89 Designs Razorbill - Design and Build
Doctor Derek Doctors

posted on 5/12/18 at 05:56 PM Reply With Quote
T89 Designs Razorbill - Design and Build

So 4 years on from the start of T89 SSL build diary with the car designed, built, raced, developed, magazine featured and finally sold its time to start all over again.

Over the past 4 years the 3 most asked questions have been:

1) Can you do one with a full body so I can use it on trackdays
2) Can you do one with a car engine
3) Can you do a Chain drive Diff Version

I addressed 1 & 3 with the Sports Racer and Chain drive Diff add-on packs for the Single Seater plans but I wanted to properly cover 2) and do a single donor, car engine Sports Racer / Sports Libre car that could be used for trackdays, sprints, hillclimbs and racing.

I have decided to use the same Lola T492 recreation body from Equinox products as its gorgeous looking, simple and relatively cheap (~2000 for a complete set)

For the engine it was a pretty simple choice, I have decided to use the B5/B6 era VW/Audi Passat/A4 1.8T Engine and gearbox, its a bit of a no-brainer for the following reasons

- They are dirt cheap, B5 Passats and A4s cost around 300 to 500
- The engine is robust and hugely tuneable, 150 upto 500bhp with 250bhp achievable for very little cost
- They use a longitudinal transaxle mimicking the layout style of a Hewland without the huge bill
- The uprights use a bolt in hub carrier (like the rear of a sierra) that can be easily bolted to a bespoke upright
- The gearbox is the same as a Porsche Boxster meaning a Mid-engine gear linkage is available from ebay & breakers
- There is a big aftermarket community around these engines meaning readily available mod parts like uprated clutches.

Other choices made so far are:

- Locost/Haynes inner wishbone bushes
- A universal upright that is used on all 4 corners
- Wilwood Powerlights all round
- Mk2 Escort Steering rack (the Lola originally used this as well!)
- Full MSA spec ROPs
- Minimal parts fabrication, I want more off-the-shelf parts that the Single Seater

I am currently deep into chassis design and will post pictures up ASAP, there are plenty on www.t89.co.uk and T89 Designs Instagram and Facebook already.





Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~5k.

Plans and Drawings available, U2U or e-mail for details.

Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.



www.t89.co.uk
www.racecarwings.co.uk

callan@t89.co.uk

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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jeffw

posted on 5/12/18 at 07:21 PM Reply With Quote
Going to be epic Cal, looking forward to a drive
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MikeR

posted on 6/12/18 at 12:27 PM Reply With Quote
First thought - if people are competing they're likely to want to be competitive. Bearing in mind MNR and MB both have fully bodies which have been through wind tunnels it may be worth designing the chassis so it possible to adapt / change the body easily. That way if the car is great but the aero lets it down then it wouldn't be a major issue to update the aero.

Ok actually my first though was "cool". Good luck and keep people posted. I've often wondered about doing something similar with the mechanicals on a road legal single seat 1960's designed car. Having not finished the locost its still a dream.

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Doctor Derek Doctors

posted on 6/12/18 at 02:28 PM Reply With Quote
The question of competitiveness can be addressed in two ways, 1) What is its actual competition and 2) Will it actually be uncompetitive.

Starting with 1) first. Neither the MNR F17 or the AB Escala/Sabre are actually in competition with this car. For a start this is a homebuild designed with price and manufacturability in mind so people wont be aiming for the same end result as if buying one of those. Also the MNR F17 (I think) is bike engine only so its a completely different thing. And while there is a car engine AB Escala, a full Ecoboost build will be ~10x the price of this car to build thus considering them in direct competition is a waste of time, if you can afford 10x the price you'll be buying something 10x more expensive. I've been mindful not to design something that's already out there available (IE an ultra developed Bike Engine Sports Racer) and isn't aimed at the same class (I don't think there is any race series apart from the pretty high level OSS Championship where this could race against either the AB or MNR.

And with point 2) they have been in a windtunnel which from talking to Andy and Marc has been aimed at reducing drag due to the bike engined roots of the cars. But with this, while the upper body may be from 1978 the underside is much more developed, the Lola body with its high sides leaves room for two huge underbody venturis running down either side that, combined with a specially designed pair of RaceCarWings.co.uk wings should generate massive downforce. Fitted with an engine that can easily go to 300bhp makes it more of a High Power/High Downforce CEC than a Low Weight/Low Drag BEC

People levelled a similar criticism to the SSL project "it wont be able to compete with a Gould/OMS/Force" which was a strange comparison to make as its a 5k homebuild car and also didn't turn out to be entirely true, with my little homemade 600cc car holding its own on the timesheets.

We'll see how it goes though... and hopefully the picture uploading might get fixed so I can add pictures!

Other random details:

- I have now weighed the engine and gearbox and it comes in at a not very svelte 193Kg but this is everything including the diff and fluids
- A very kind gentlemen is sending me a spare GTS turbo kit that should push me to over 275bhp
- I am going to use some aluminium monocoque style parts on the chassis, I'm hoping this will keep weight down and make the chassis build a lot simpler.
- I have now confirmed that 280mm Audi brake discs and Powerlite caliper will fit inside a 13" wheel, sadly there are no 15" tyres small enough to fit under the body which was designed for small 13" 70's cross-plys
- The full Boxster gear linkage has now been sourced for 80 from ebay, it will have a Porsche gear lever!
-The universal upright is nearly finished in terms of design and I am hoping to order one to test assemble imminently.





Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~5k.

Plans and Drawings available, U2U or e-mail for details.

Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.



www.t89.co.uk
www.racecarwings.co.uk

callan@t89.co.uk

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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AdamR20

posted on 6/12/18 at 02:32 PM Reply With Quote
I like your mantra with this - I'm also a huge believer that a 'shed build' can trump something 'professional'.

Very keen to follow progress and see how it turns out, thanks in advance for sharing!

[Edited on 6/12/18 by AdamR20]

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jeffw

posted on 6/12/18 at 09:44 PM Reply With Quote


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MikeR

posted on 7/12/18 at 09:13 AM Reply With Quote
Not sure about the wooden bits but that looks fab.
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jeffw

posted on 7/12/18 at 01:05 PM Reply With Quote
Some low cost Marine Ply would be the answer
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jeffw

posted on 7/12/18 at 01:07 PM Reply With Quote
This is what it will/could look like

https://racecarsdirect.com/Advert/Details/94582/lola-t492-sports-2000

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Doctor Derek Doctors

posted on 7/12/18 at 05:36 PM Reply With Quote
quote:
Originally posted by MikeR
Not sure about the wooden bits but that looks fab.


The area where the wood is (extending in to the side of the chassis), is where the full length venture tunnels will be. With an area of 340 x 250mm down the side opening up at the rear they should be pretty powerful.

I'm tempted to veneer panel them to go for a 'Woody' effect.

In other news;

-Boxster gearbox mounts have gone on to replace the original Audi mounts, these are lighter tidier steel mounts than the large aluminium castings on the Audi and mate up to the chassis much lighter.
- The Turbo kit is on its weigh from America
- The body has been weighed and the whole lot comes in at 40.5Kg
- Current weight calculations put it at 530-550kg ready to race.
- Initial investigation into the cooling system shows that it will nicely connect up to a rear mounted Polo radiator





Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~5k.

Plans and Drawings available, U2U or e-mail for details.

Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.



www.t89.co.uk
www.racecarwings.co.uk

callan@t89.co.uk

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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ettore bugatti

posted on 8/12/18 at 06:43 PM Reply With Quote
Great project!

Interesting to see how the chassis and suspension develops out.

How flexible is the chassis for different drive trains?

I can imagine, people want to stick boxer engines or v8s in that space.

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Doctor Derek Doctors

posted on 8/12/18 at 08:52 PM Reply With Quote
The Audi and Porsche Boxster 5-speeds. Are all the same gearbox so that gives a pretty wide choice of I4s, V6, V8 and Flat 6 engines. I'm pretty sure an Impreza flat 4 could be converted to FWD layout to sit in the back of this as well.

The chassis is 950mm wide a cross the roll hoop so plenty of width and due to the Lola originally having a Hewland with a large bellhousing the rear bulkhead and roll hoop are surprisingly far away from the rear axle centre line so there is plenty of length as well.

Latest update, I have just bought a cheap pattern clutch slave cylinder, these come with a normal screw in brake pipe fitting rather than the plastic push fit rubbish that Audi and Porsche fit as standard.





Designer and Supplier of the T89 Designs - Single Seater Locost. Build you own Single Seater Racecar for ~5k.

Plans and Drawings available, U2U or e-mail for details.

Available Now: The Sports Racer Add-On pack, Build a full bodied Sports Racer for Trackdays, Sprints and Racing.



www.t89.co.uk
www.racecarwings.co.uk

callan@t89.co.uk

NOTE:This user is registered as a LocostBuilders trader and may offer commercial services to other users
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Ugg10

posted on 8/12/18 at 09:11 PM Reply With Quote
Looking very good, love the concept, how woukd thus compare to a Spire GTR? There are some of these with the Audi 1.8t in the back, looks like a similar concept.

The scoops can be made FWD only by removing the centre diff and putting in a locking spigot and a new rear plate. I think it only works with 5 speed boxes, this is what was used in the SDR Storm WR3 iirc, the current storm owner may be able to provide the conversion and gear change and kits are also available from AUS.

A 2.7 twin turbo fromthe A6 crossover thingy would be rapid but heavy.

Any way of making it road legal?





---------------------------------------------------------------
1968 Ford Anglia 105e, 1.7 Zetec SE, Mk2 Escort Workd Cup front end, 5 link rear
Build Blog - http://Anglia1968.weebly.com

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