Where modified cars should be going…

Posted on August 24th, 2007 in Driving Emotion,Economy,Handling,Opinion,Power,Technologies,Turbocharging by Julian Edgar

The other day a reader wrote in, saying how he was disappointed with AutoSpeed. Amongst other things, he said that there were plenty more powerful modified cars around than those we are featuring – all we had to do was attend some dyno days and go to the drags.

That we are no longer particularly interested in featuring typical straight-line drag cars, and typical horsepower dyno hero cars, hadn’t occurred to him.

I told him in my reply that AutoSpeed was (and is) changing in editorial direction; if he liked the Australian magazine Street Machine (he’d said in a previous email he did) I thought it very unlikely that he would like AutoSpeed, both now and in the future. Therefore, it would seem best that he stop reading AutoSpeed, rather than just go on being frustrated with us.

[Incidentally, this idea that if you don’t like us, don’t read us, seems to offend people. But to me it makes perfect sense: what’s the alternative – I encourage those readers to persevere, even though I know they won’t like what is coming up? To me that seems completely hypocritical.]

Anyway, I was reflecting on the reader’s comments, especially in the implication that more power is good – and even more power is therefore better. As I’ve stated previously, I think that many modified cars in Australia are heading in completely the wrong direction – they’re huge, hugely heavy, and hugely powerful. But rather than put this so negatively, let’s look at the issue more proactively. What makes for a good modified car? (And so, one that we’d be delighted to feature?)

Firstly, I think that the way that people keep shifting the goal posts is self-defeating. In other words, you should be able to state what makes a car good – and those criteria stay valid not just until next week’s horsepower hero shootout, but for a long time indeed. Secondly, those criteria should be all-encompassing, not picking out just one aspect of performance as if that’s the be-all and end-all.

So what are the criteria?

I reckon that a good high performance road car needs a power/weight ratio of about 200 hp/tonne. So a VE Commodore at around 1800kg therefore needs about 360-odd horsepower; a 1300kg Impreza WRX about 260hp – and a 850kg Honda Insight ‘only’ 170hp!

Now for many, that power/weight figure will seem far too low – and that’s fine. Cos there’s a sting in the tail – the average power over the rev range also needs to be high. For example, when the engine has a 6500 rpm redline and peak power revs of 6000 rpm, 90 per cent of peak torque should be available from 2000 rpm.

And for that power to be usable in as many conditions as possible, all four wheels need to be driven. And preferably driven with an intelligent control system that allows active splits of torque, laterally and front/rear. 

Brakes? I don’t think that there’s much wrong with current big systems, featuring ABS and electronic brakeforce distribution. But to put it against some criteria, the system needs the ability to pull 1g stops time after time on a public road.

Handling? Again I think many current cars do an extremely good job in this area, but I’d add that to achieve real handling speeds on real roads, the width of the car needs to be restricted – so much more WRX size than BF Falcon, for example. (If you don’t agree with me, tell me how a wide car can be as fast on a narrow windy road as a car that handles as well but is narrower. The answer is self-evident: it can’t.)

I think that a performance car needs to be fuel-efficient, particularly when it is not being driven hard. And by fuel-efficient, I mean better than 10 litres/100km in normal non-performance driving in urban conditions. For the same environmental reasons, the car should meet current emissions legislation.

So the criteria are:

• Power/weight ratio of 200 hp/tonne
• 90 per cent of peak torque available from 2000 rpm (when there’s a peak power rpm of about 6000 rpm)
• All wheel drive with active electronic control
• Big brakes with ABS (easy!)
• Handling at least as good as the current high standard of performance cars
• Fuel economy in non-performance use of better than 10 litres/100km in urban conditions
• Meets current emissions standards

These criteria won’t be dated by tomorrow and are not influenced by brand loyalty or the max power someone’s now getting out of a particular engine.  (Note: I haven’t made any mention of crash safety, but if you wish you can add another line of your own.)

Looking at the listed criteria, some car design points are inevitably reached.

The first is that the car should be small. This reduces the required power to maintain the power/weight ratio, makes it easier to achieve good braking and handling. Secondly, a forced aspirated engine is needed – what other engines can develop as flat a torque curve? The fuel economy requirement further suggests a turbo engine – one that is effectively smaller when being driven normally and lacks the mechanical power drain of a supercharger when being driven hard.

In fact, looking at the list, the nearest car I can think of is an Evo Lancer – but one fitted with a better designed turbo engine, perhaps a sequential twin turbo 2.5 litre V6 diesel.

So you can see that when someone tells me how performance road cars are being much advanced by 1.8 tonne, 6-litre V8 sports sedans that in normal use get 15 litres/100km, I am less than impressed. Or when there’s great excitement over a 300kW at the wheels 2 litre turbo with a torque curve that looks like the side of a mountain, I think – who cares?

But that’s just me. If you think I have everything cockeyed, what is your list of performance criteria – and what sort of car design does it lead to?

(And here’s a further thought: an electric car with four in-wheel motors and a hi-po lithium ion battery pack could achieve all these criteria beautifully…)

16 Responses to 'Where modified cars should be going…'

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  1. Bret said,

    on August 24th, 2007 at 11:00 am

    Hi Julian, great article and thought provoking once again.

    An advantage of using electric motors on each wheel is that you can just about eliminate transmission loss. I’m always astounded that we happily accept up to 30% loss through a conventional transmission, energy that is simply wasted. The use of four electric wheel-motors could provide greater than 90% transmission efficiency, making much greater use of the power we generate to start with, whether the source is coal or petrol/diesel generated.

    With regard to torque spread, I see another solution. If you use the above four wheel electric motor option, then have a conventional internal combustion engine combined with a generator, why does the IC engine need a torque spread at all? Since the wheels are driven electrically, the engine could run at it’s peak efficiency RPM all the time, feeding power to a DC bus. This could then be converted/inverted via variable frequency drives etc to supply the wheels motors. As load increases, the engine is fed more fuel to generate more torque without increasing the RPM. Imagine the cam designed only to run at a very small rev range? . Ever seen one of those sweet little Honda “inverter” suitcase generators?

    On a whole other subject, since your three-wheel recumbent bike is so easy to pilot on two wheels, did it ever make you consider a two-wheel version?

  2. Stuart Bunning said,

    on August 24th, 2007 at 4:40 pm

    Seeing Im the reader that started this blog I figured I would clear up a few things that appear to be misinterpreted.

    I mentioned goto the drags or a dyno day because you could find some new cars to write articles on instead of re posting a 10 year article on a hypo hemi turbo valiant or continue to write articles on peddle power that to me didn’t seem related to cars performance or not. Yes I do read street machine but thats just one of about 10 magazines I purchase each month. And while were on the subject of money I do pay for autospeed so you can see how I could get upset when Im told to stop reading it.

    I know the trend these days is 1000+HP at the wheels. I do agree this is just silly but articles on human powered vehicles got we thinking is this a car site of a not ?

    Oh and the comment you mentioned above
    “I was reflecting on the reader’s comments, especially in the implication that more power is good – and even more power is therefore better.” Gee I don’t recall saying this ?

    I could go on but Im sure my post will be edited anyway.

  3. Ed said,

    on August 25th, 2007 at 12:29 am

    I have to admit to feeling a similar sense of disapointment at some of autospeed’s content over the past while. I bought my subscription for the tech articles. being new to anything remotely mechanical, the old tech stuff was great. I also loved looking at some of the feature cars that could give some inspiration however when “the changes” came in not long after I got my sub, a lot of the content I had enjoyed was either dropped or recycled.

    That said, parts of the new format are great. I love the engineering stuff. if I’d had any idea what engineering was while I was at school I would have worked my ass off to get into it. But this is a car zine and I’m still not really interested in your human powered vehicles. certainly not the proportion of new content they represent.

    on “not reading” I paid for it, then you changed it seams a pretty good reason to feel frustrated,

  4. Matt said,

    on August 25th, 2007 at 10:48 am

    I can understand that people fail to see the relevance of the HPV articles, it’s not like building a bike from scratch has the same applicability as (say) bolting in a new exhaust and testing the difference.

    Maybe some relationship neds to be drawn back to doing something similar to cars. For example, with all the suspension analysis: how can one go about assessing (and more importantly, altering) the existing geometry of their car suspension.

    A book like Fred Puhn’s How To Make Your Car Handle is very insightful. Possibly a bit outdated, but there’s practical tips on stuff like measuring (and altering!) bump steer, roll centres, and so on. Also some interesting antiquated concepts like Z-bars (in essence a reverse anti-roll bar)… Might be worth a book review?

  5. Ben said,

    on August 25th, 2007 at 12:37 pm

    Bret, what about another (similar in functionality) system? Some kind of compressed gas system with four motors. I believe compressed gas systems to be more efficient than electricity, lighter, easy to diagnose, cheaper, and significantly smaller (case: look at the price, size, and weight of an electric rattle gun, then realise that you can’t do as much with them).

    And using a small built-in electrical compressor (mains powered), a plug-in hybrid style system could be made easily.

    I’ll try and get back to you with more data as soon as I can.

  6. Gordon Drennan said,

    on August 25th, 2007 at 1:57 pm

    Here’s how I’d like to be able to modify my car. A second set of injectors designed to inject gas. A secondary engine computer that looked at the signal going to the standard petrol injectors and either fed it through to them so the car was running on petrol, or translated to the appropriate voltage and duration signal for the gas injectors to feed the engine the equivalent amount of gas so the standard ECU thought the car was running on petrol but was actually running on gas. A spare wheel shaped and sized gas tank to go in the spare wheel well and connected to the gas fueling system by a dry-break connector. And a compressor to refill the gas tank up from my home’s natural gas supply overnight. So for short range day to day round town stuff you pull out the spare wheel and drop in the gas tank and plug it in an run on methane for an equivalent cost per kilometre of 5c/litre petrol. And for longer distant runs you’d pull out the gas tank, drop the spare wheel back in, and run on petrol that you can get anywhere. There’s a company (GTI) trying to get the gas injection and ECU signal coversion stuff on the market. The rest is just obvious. Australia’s got huge amounts of natural gas. Its absurdly cheap, and we’re selling to China by the boatload for the equivalent of 3c/litre petrol. Using its not rocket science. Its like using LPG only far cheaper still. The only problems are availability and range, that’s why I suggest what I did.

  7. Jonathan said,

    on August 28th, 2007 at 2:36 am

    Modified performance cars are passe! Escalating fatalities arising from street racing & citizens’ complaints against reckless driving by hoons are creating an anti-movement against performance cars. Rising insurance premiums are a sure sign that everyone pay for the senseless acts of a few hoons.

    Movies like “The Fast & the Furious”, “2 Fast 2 Furious” & “The Fast & the Furious: Tokyo Drift” glorify illegal street racing at its worst. The US import scene aka SEMA is a huge marketing scam pushing out all sorts of performance equipment mostly overpriced, unproven & unsafe products to the masses. They encourage car enthusiasts to spend huge amounts of money aka “Pimpin’ My Ride” on their cars – on AV, car graphics, tuning & Big wheels. Only in the US market you’d find a turbocharged or supercharged Honda VTEC. Honda’s VTEC engine is strictly designed for NA purpose – for high rev & high lift cam effect. The con-rods are thin width design in order to rev higher while the block is an open deck format. This engine was never design for forced induction! In Japan, renowned tuners like Mugen, Spoon & J’s Racing enhanced the VTEC engine in NA form, never by forced induction. Jap performance houses eg. Trust/GReddy, HKS sell Honda Turbo kits in the US but never in Japan. Why?

    Most modified performance hero cars featured in Magazines like “Fast Fours” & “Hot 4s” are often contradictions – body kits which are an aero-drag; big, heavy bling-bling wheels which affect acceleration; power graph like Mt. Everest; ultra low stance which prohibits going over humps & car graphics that shout out like a McDonald’s big Yella “M” sign. I always have a good chuckle seeing these hero cars at my news agent magazine counter – nice to see but definitely not worth to buy the mag.

    These days due to environmental concerns, global warming & rising fuel prices – performance should have a re-look – “Think outside the box”. Instead of a V8 monster weighing 1.8 tonnes, why not a Smart ForTwo with a Hayabusa engine or the Subaru STi quadbike for club events. For Pt A to Pt B, a petrol-hybrid, a turbo-diesel-hybrid or even a human-propel recumbent trike would be ideal. Cheers!

  8. Tim said,

    on August 28th, 2007 at 8:28 pm

    I agree with almost all of your points, and applaud the direction you’re taking the publication.
    I must disagree, however, with your comments on brakes. For sure, good brakes are essential for a performance car, but there is more to good brake performance than bolting on a set of big discs and calipers.

    For a car to get anywhere near 1g deceleration, every tyre must be at its limit of traction. That means, brake balance must be tuned for the vehicle’s weight distribution, suspension configuration, and even tyre choice. If any wheel is under-braked, the deceleration potential of the car will not be realised.

    Of course, a good ABS and electronic proportioning system will help with this, but it must be considered that ABS (and to a greater degree, stability control) is tuned to the car’s OE configuration. The ABS of an OE brake system knows pretty well what pressure, and what application rate will pull you up in the shortest distance, whereas on a modified system it will need to “hunt” for the correct fluid pressure. Performance will be compromised.

    The recent trend of adding monster brakes to the front axle, and not bothering about the rears “because the fronts do all the work” goes completely against the principles of brake balance. Sure, the car may get better deceleration for a given pedal effort, and the front brakes may stay cooler with bigger rotors to dissipate heat. Both of these factors may make the car feel like it has more powerful, and more fade-resistant brakes. But unless the brake balance is maintained the rear wheels may be under-braked: the rear tyres will have traction to spare when the fronts lock up. Limit-of-traction braking performance will be inferior to the OE braking setup.

    Any change to the braking system, which includes the pads, calipers, rotors, suspension, wheels and tyres has the potential to improve or degrade different aspects of the car’s brake performance. As with every other modification, measurements before and after are key.


  9. Ben Styles said,

    on September 14th, 2007 at 3:19 pm

    Tim – I think you are on the money.

    What most pushers of the big brake upgrade fail to detail the impact of these upgrades on the ECU that controls the ABS etc.

    The only way you can see the full benefits in terms of maximum negative g’s of a massive brake upgrade (e.g. shocking SS commodore calipres upgraded to Brembos) is to actually remove the ABS fuse.

    Why? The g-sensor/pressure sensor etc from the ABS thinks that the car should have lost traction at massive deceleration and kicks in, so you never reach the new system’s potential anyway. This has been tested and proven extensively elsewhere. Problem is, you then lose the safety benefits of ABS in the first place.

    Much better idea to try to maximise the factory setup with pads, lines, booster brace, fluid etc. If this fails, then sure – go shopping.

    BTW – I take the ABS fuse out whenever I go for a hard drive with my upgraded standard braking system, as ABS does not allow the 5 – 10% slip that your tyres actually require in order to reach maximum traction under braking. (the tyres need to be turning 5-10% slower then the car is moving without locking)

  10. Ben Styles said,

    on September 14th, 2007 at 3:46 pm

    Ultimate performance machine:

    • Definitely less than 1000kg
    • Ultra-light unsprung weight (magnesium alloy A-arms, wheel nuts and rims)
    • Active electromagnetically controlled dampers (driver definable of course!)
    • Driver selectable ground-effects undertray (skirts and tray drop/extend upon press of button)
    • Driver selectable ride-height (to compliment effectiveness of ground-effects)
    • Driver selectable torque split active AWD, so I can choose to hang the tail out in the dry today, or drive flat out in the wet tomorrow
    • Complete downloadable telemetry data storage onboard with bluetooth data transfer to my PC for analysis
    • Live data dispays for brake temp, oil temp, tyre pressure.
    • Quick-release seats, stereo etc for further instant weight reduction on track days
    • Small capacity direct injection, supercharged/turbocharged engine similar to Nissan Micra/Golf GTI engine OR for non-boosted a 2.5 litre V6 with VVT and VVL. Both engine options to have user definable exhaust options to allow switch to track-day emission spec…engine map selection to suit fuel quality (including option of running elf TurboMax etc!)

    Wishful thinking I know!

  11. Ben said,

    on September 16th, 2007 at 12:26 pm

    Wishful thinking, yes, but it’s all possible. However I think that the exhaust is a bit overkill. It the effect on weight would be like having a dual exhaust, and only using one side, plus the weight of the changing mechanism. Far better to have a quick-release system and be supplied with a kevlar glove and a side dump pipe for easy changes.

    Thinking about the datalogging, why not have the memory as a bluetooth storage device? So that downloading the data becomes as simple as removing a little box (with no cables) and putting a blank one in the same spot.

  12. Matt said,

    on October 16th, 2007 at 10:47 pm

    Hey Brett,
    What you are describing is present in the Chevy Volt concept car. It uses 4 in wheel motors and lithium Ion batteries to give a fuel free range of 65km, recharged at your powerpoint at home. Then if you exceed the 65k’s a small 1L generator (which they say can run on multiple fuels) engages which recharges the system allowing you the range capabilities of a standard car. So theoretically in everyday driving you would probably never need to use petrol, but if you needed to you could still up/go down the coast for your holidays. They say it will be in production in 2011 but i don’t know how much you can trust them. The only problem is what you lose in transmission losses you gain in the conversion from chemical->mechanical->electrical->mechanical energy losses. But considering an ICE loses 80% of its energy as heat while an electric system is the other way around, for most of your driving you are being more efficient overall.

  13. on December 30th, 2008 at 8:33 am

    I think you guys are missing one massive point , wife & kids! Yep, you must all be single selfish snots! I love tuff turbo 6 fords and v8s, what else can tow a big speed boat , a wrx?, sorry not heavy enough, buy the way, turbo falcon six is quicker too, will carry my three kids in more comfort, drives better, looks better , is Australian ( I’m supprting local jobs), and I could just go on & on….

    When you guys relize that little cars can’t suport a real mans lifestyle , or a big guy ( I’m a 135kg power lifter) in any comfort. So if your 5ft5″ with a girls body you’ll be quite happy in a cramped little import, but if your a big Aussie man it has to be a performance falcon or commodore , particularly if you like a big family speedboat. Oh, my xr6t does 0-100 in 5.1 sec and at this stage its unmodified, it handles , brakes and drives great, a bump does not effect it mid corner like a small car gets thrown of line because it’s to light ( it’s safer to, has a 5 star safty rating, unlike your imported tin foil cans).

    I just want to say, when you guys buy a house, have a family, and truley start living a real life, your thinking will change in what a great road really is , it has to be a real GT,

    And if your 4wd wind up toys are so good, why did they get beeten in the WET! By a big old 300kw hsv at bathurst production a few years ago? That’s a tight harsh track that’ll test any car to destruction, why in the pooring rain did the hsv kick the ass of all your import rubbish? Why? … Ah.. Silence is bliss! Sit back down children, or be smacked down!

  14. Julian Edgar said,

    on December 30th, 2008 at 8:45 am

    Donaldsupercharged, on the basis of your comments, how on earth did Real Men exist in Australia with the Commodore and Falcon models of, say, 10 or even 20 years ago?

  15. Ben Styles said,

    on December 30th, 2008 at 9:17 pm

    Donaldsupercharged, you seem to be missing the point of this post altogether…I have worked for one of your beloved ‘Aussie’ manufactureres, and spent plenty of time belting turbo sixes and V8’s about the place…I have also owned a number of Nissan performance models, and worked for a Japanese auto manufacturer – there NEVER will be a one-size-fits-all…all cars have their upsides and downsides! Your huge hunk of metal XR6T handles relatively well considering its weight in standard trim…but on the twisty stuff is much more difficult to live with than say a 350Z, a WRX (not my kind of car either) or a Mazda MX5. If you need to tow, and are bigger than the average Aussie bloke (sorry mate but 135 is WAY above average), then that’s great for you; the big hunk of metal XR6T that guzzles enough fuel to sponsor a new Taliban Suicide Bomber every day, will be right up your alley…and yes it must be fatastic towing a boat with the XR6T…I certainly envy you there.

    This post is about the FUTURE…not the past. The old school brigade that the XR6T belongs to simply uses the incomplete formula of “more power = more straight line speed (and makes nice sounds while doing so)”.

    A 2-tonne tin-top- like the XR6T is a relic of the past, and is unfortunately heading the way of the dodo. This upsets me too sometimes…I love the sound of a V8 or a boosted large capacity 6 as much as anyone…but we have to accept the realities of physics (lower weigth+lower COG+better weight distribution+better aero = better all-round performance). Performance cars of the future will encompass all of these things, as you will note if you take the time to read the other posts.

  16. Jay said,

    on January 2nd, 2009 at 8:50 pm

    As well as agreeing with Julian and Ben I have a few questions for Donaldsupercharged (with the turbo Ford)

    Your “turbo falcon six is quicker” in a straigh line or around corners? Please re-read the second paragraph

    Regarding the comment “And if your 4wd wind up toys are so good, why did they get beeten in the WET! By a big old 300kw hsv at bathurst production a few years ago?”.
    “4wd wind up toys” were banned from the ATCC because they were too fast, is that not right?

    Finally, regarding the comment “Sit back down children, or be smacked down!” WTF are you on about? I don’t understand this comment (I’m not a bogan).
    I guess you are telling everybody to shut up (in a blog where readers are invited to post comments). And if they don’t you will metaphorically beat them with your own comment.