bigger engine??

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Ian.G Wrote:I think the crux of the problem is smaller NA engines wont make stupendous power - they are limited by capacity and have to make their power with revs.

For example - look at something like a Suzuki Hayabusa engine - its a 1.3L capacity but it makes nearly 180bhp - and its all done from revving the engine to nearly 12,000rpm. Lots of revs = lots of cash in order to give the engine the strength it needs to withstand what happens when you push the motor an extra 2000-3000rpm. From a purely financial point of view building up a 4AGE motor to get to the stock HP output of the Honda K series motor is an expensive job.

This is why I think using a higher capacity engine will get you the power you require without the engine being so wildly tuned.

For the about price of a 220bhp 4AGE engine I can buy a pair of complete Honda F20C engines with transmissions and all. Right now in the UK the honda K20 series motors actually fetch more money used than the F20 motors because they are extremely popular for use in Lotus elise cars in their std transverse configuration.

Like you say - the power is possible for less expense with the 4AGE engine if you go the forced induction route - dont get me wrong - I really like turbocharged cars - I've had some good fun in them over the years - but I think NA suites the hachi more. Obviously the issue with using another motor is its never really a straight swap and lots of additional work needs to be done to the rest of the car to support the engine transplant.

Hopefully though - if done properly there is no reason why the large capacity engine shouldn't last as long as it would have done in its original car - and I dont see any real reason why you would need to spend more money tuning it as any more will be way beyond the limits of the chassis

Make's lots of sense this post. Honors 'there's no substitute for cubic inches'. And a larger capacity engine probably improves engine life due to more torque on tap at lower revs. Engine doesn't need to be reved as much as a smaller engine. This leads to lower average piston speeds which prolongs engine life.

Small displacement engines as said feature low torque especially at low revs. This is mostly due to a small stroke. Small stroke leads to slow air speeds through manifold and cilinder head and in general doesn't promote volumetric efficiency. This lowers specific torque figures even further than you would suspect from the lower capacity alone...

A turbocharger or other supercharging device equalizes things a bit by promoting air speeds in the intake and cylinderhead. (Bigger volume of air in same area gives higher flow rates and higher air speeds.) And as a further bonus more mixture burns longer giving the crankshaft a longer 'kick'. Higher cylinderpressure over larger amount of degrees crankshaft.

So bigger and/ or supercharging devices deliver massive amounts of torque. Which isn't always appreciated. This imho has nothing to do with the engine but everything with the chassis and drivetrain.

As an example a standard Dodge Ram SRT-10, which features an enormous 505 cubic inches of displacement and has low down grunt who makes every other engine feel like a moped, has a very nice chassis setup. You can throw the car around like it's a 1600 pound hatch. Virtually no lift off oversteer and some mild understeer if you throw it into a corner. Only when you take it to the absolute maximum permissible speeds the snake bites with gargantuan drifts, sudden lift off (and braking) oversteer. But all very controlled, and fun for a 4500lbs. - 430 wheel horsepower monster car...

(Sorry I'm going off topic... :wink: ) Anyone wanting to see this monster attend my next dyno shoot out in Goes (The Netherlands). Or watch this video (Sorry dyno only. No street action available at this time.)(Prototype in actie
)

Now we bolt on a Paxton centrifugal supercharger boosting at 7psi and a full exhaust system with headers. Power leaps up to 620 wheel horsepower and wheel torque goes up to 880Nm.. (No typo's here ). Wheel torque was 630Nm as standard. Now you can develop wheel spin up to or over 100mph at a blip of the throttle. Even with the very good Pirelli 305/40-22 Scorpion tyres.

My point is that you have to modify the chassis to cope with the increased wheel torque. This to offer sufficient grip and traction to be able to utilise the potential increase in speed.

Nothing new, I know, but just wanted to bring this to everone's attention.

But cost goes up with further mods so I must agree that a certain power and/ or torque level should not be exceeded when tuning a standard or light modified vehicle.