985cc Turbocharged Nova Sprint Car

[novarally]

this thing deserves a 600bhp let.

It is tempting. Not many people have 1000 bhp per tonne......

[stt]

An oversquare engine allows for more and larger valves in the head of the cylinder, lower friction losses (due to the reduced distance travelled during each engine rotation) and lower crank stress (due to the lower peak piston speed relative to engine speed). Because these characteristics favor higher engine speeds, oversquare engines are often tuned to develop peak torque at a relatively high speed.

The reduced stroke length allows for a shorter cylinder and sometimes a shorter connecting rod, generally making oversquare engines less tall than undersquare engines of similar engine displacement but wider and longer (for engines with vertical cylinder axes).

By changing the crankshaft and modifying the connecting rod(s), piston(s) and/or engine block an engine can be "de-stroked". This reduces the displacement and consequently the torque of the engine, but can allow it to run at higher speeds and in fact develop greater peak power.

Oversquare engine examples

Oversquare engines are extremely common, including both Chevrolet and Ford small block V8s. Most Boxer (horizontally-opposed) engines (such as those built by Volkswagen, Porsche, and Subaru) feature oversquare designs since any increase in stroke length would result in twice the increase in overall engine size.

This is particularly crucial in Subaru's front-engine layout, where the steering angle of the front wheels is limited largely by the size of the engine. Although oversquare engines have a reputation for being high-strung, low-torque machines, the Subaru EJ engine develops peak torque at speeds as low as 3200 RPM.

Extreme examples of oversquare engine designs are found in Formula One race cars, whose rules tightly limit displacement and thereby require that power be achieved through high engine speeds. Stroke ratios of 2.5:1 are typical, with engines capable of 19,000 RPM.[citation needed]

Stolen from wikipedia as I can't be arsed to type it out from my books but it gives you the general plus points!

[novarally]

Small update......the engine is being put back together with a set of new pistons, along with shells, oil pump and Total Seal piston rings. The sump is also being modified to hold a bit more oil, as oil pressure seemed to be a problem with the higher level of cornering force that the car can now generate.

I don't have the money at this time to opt for a 'proper' engine build, so the plan is to run it with slightly less boost and/or revs, and hopefully it will last out this racing season, and allow me to fine tune the rest of the car.

Longer term I intend to get another engine built, using steel crank, steel rods and forged pistons. This may well take the form of a de-stroked 1300/1400 (possibly 16v), but I need to discuss this with experts to decide the best way forward and check out the likely costings.

[Edd]

Did your local parts chap give you any info on getting a 1.0L engine from brazil ?

[novarally]

Did your local parts chap give you any info on getting a 1.0L engine from brazil ?

I've drawn a complete blank on that one. They were very helpful, but tell me that GM Europe have no connection to GM Americas, so they can't access the database to even view the parts, let alone order them.

He gave me a contact name and number at a company called 'Vaux-Pro', who supply brand new crate engines to the Vauxhall Dealer Network, but when I spoke to them they were also unable to assist with sourcing stuff outside Europe.

So I think that option is out of the running, plus the more I think about it the more I think the engine block is unlikely be identical to a Nova (e.g. it might have lug mounts cast into it for a PAS pump).

[fearless]

Have you considered using this system to help your oil pressure issues

http://www.accusump.com/


I know a few rally boys who use it - Martin Bowyer (Bowyer Developments) has spec'ed it for the Engine for our Corsa S1600


Its basically a pressurised oil tank - that release's oil if the pressure drops

Might be worth looking into



Dave

[novarally]

Have you considered using this system to help your oil pressure issues

http://www.accusump.com/


Dave

Hi Dave.

I am aware of those systems, and they seem to work well.

If I go the whole way with the engine as I hope, I will probably bite the bullet and have a proper dry sump system on it.

[stt]

I cant wait to see the next incarnation of this engine,
I love the development of this car, a short stroke 9500rpm screamer coming soon then?????

[novarally]

I cant wait to see the next incarnation of this engine,
I love the development of this car, a short stroke 9500rpm screamer coming soon then?????

The sooner people buy up all my stock of Nova spares and race/rally bits, the sooner you will see a new engine in it............

[Kev Turbo]

So glad your sticking with the 1.0 engine Colin,

The big block options would really have spoilt the car IMO,

Glad you can finish the season and hopefully get some good results from the car!