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Some of this week's Letters to AutoSpeed!

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BOV Testing

First, I want to say that I love your magazine - especially the tech articles and DIY stuff. I'm a regular participant on different internet forums and have found a lot of threads discussing the effect of dump valves (aka BOV, bypass valve, bla bla). There are a lot of theories out there, like:

- a bypass valve is more effective than an atmo dump valve, as the air stream goes back into the compressor

- no blow-off valve at all will destroy your turbo, as the pressure wave will force its way through the compressor backwards

- OEM turbo cars come with bypass valves only to get rid of the farting noise from the intake...

I would like to see a test of these theories. It might be possible to attach some sort of trigger to the compressor housing that would register (optically?) when the blades are spinning and get some sort of rpm reading through a drilled hole or something. If this works, one could datalog the rpm loss with different configurations, such as:

- No dumpvalve

- Different dumpvalves

- Recirculating valve

- Different turbo size

Such a test would kill a couple of myths I think...I hope you guys find this interesting and feasible (technically possible).Thanks for a great online mag.

Arild Hofstad

Yes, there is a lot of discussion on this topic. Unfortunately, a conclusive test would require a large combination of turbo sizes and blow-off valve sizes/types together with a huge amount of time and specialized equipment. As always, nothing beats on-road testing with your particular car!

Rare R32 GTS-4

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I was just reading up on your Nissan GTS-4 article - Unknown Warrior - Skyline GTS4... You guys said something about a four-door version of the GTS-4, but had not seen one in Australia. I recently bought a 1989 R32 four-door with "front kg-m torque" written on one of the gauges. Sure enough,I got underneath the car and it is four-wheel-drive!It also has the HICAS (4 wheel steer) system as well. I have been wondering how rare they are and what they are worth, because I have met quiet a few people that have R32 four doors but no one I have spoken to has even heard of a four-door manual turbo 4WD. If you guys could give me some info about it, it would be great.


Lucky score! Can any readers provide further info?

Cool Air for Rodeo Turbo Diesel

I noticed a query in Issue 257 regarding an intercooler for a 2.8TD Holden Rodeo (Response) and you suggested contacting APS. I also want to intercool my similar Rodeo, however APS don't manufacture their intercooler for this vehicle anymore. But MTQ do - check out Their intercooler retails for about AUD$1550 + GST and comes with bonnet scoop and fitting instructions.

Brenden Cooke

Enjoying the XR6T Series

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I really enjoy the series you have on buying a Ford XR6T (starting at XR6 Turbo Guide - Part One). It is informative to read interesting insights into buying that model – price, performance and problems. I hope you will extend this type of article to other types/models of car.

It reminds me of the detailed articles that used to be provided in 'print' magazines in Australia before they decided to focus on 'hot model' articles for the teenyboppers or company car execs. These days, the magazines focus on racing the cars or telling us how great they are to drive 'flat out' on road X, but almost completely gloss over the real-life aspects of car ownership (like repair costs, fuel consumption and longevity).People that actually shell out the $$$ for a car find your type of article really very useful. Well done.

Craig Dunn

We’ll certainly be considering a similar series off articles for other models.

Electric PS for ’68 Mustang

I am interested in a column-mounted electric power steering unit.I have a ‘68 Ford Mustang rally car which is using a rack and pinion set-up. Is such a system available in Australia - and at what cost? Any info would be much appreciated.

Rick Woskett

We haven’t seen any off-the-shelf electric power steering kits but it would be worthwhile visiting some Japanese import wreckers and investigating whether any of their cars have systems that might be adaptable.

What a Load...

I just read Julian Edgar's Driving Emotion - "I'll never see big, multiple exhausts in the same way again"... What a load of crap. The message I got from the article was that there’s no need for large cars, with huge V8s, with quad exhausts. But, wait, whenever there's an article on such a car there's always huge praise on how fast they accelerate, how much fun you can have, so on and so on. This spells out one word. Hypocrite. Especially as you own a V8 yourself.

You forgot to mention the FACT that under similar driving styles (a mixture of full throttle applications plus general driving), the VZ HSV Clubsport - with its ridiculously big 6L V8 - gets better fuel economy than both the Mitsubishi Lancer Evo 8 and Subaru WRX. Hang on, but this doesn't make sense... A stupid, big V8, with *gasp* pushrods(!) getting better fuel economy than state of the art 2L turbo cars? On highway drives, mind you, the polluting V8 gets down to as low as 7-8 litres/100km. And if it's using less fuel doesn't that mean it will be emitting less greenhouse gases? By the way, all three cars are Euro 3 compliant. Yes, the HSV is a bigger, heavier car still, but that means it will more comfortably house its occupants and offer more boot space...

As for the notion that a more free-flowing exhaust does nothing to improve economy and emissions... you've got to be joking, right? The more restrictive an exhaust is, the less efficient the engine will be at dispensing with the gases, the less efficiently it will burn them in the first place, the more poisonous gases it will emit. If the exhaust is designed well, it will not only free up power and economy, it will also decrease the emissions level.

Fact of the matter is, rice burners are no more economic than "stone- aged" V8s, let alone the (apparently) so much better high-tech ones. I've still got more to say, but this is long enough already.If you want to do your bit for the environment, stop breathing - you're stealing everyone else's oxygen.

Evan Smith

Re AutoSpeed Falc #1

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It's interesting that you looked at an EF Ford in the Car Crazies articles Car Crazies, Part 1, Car Crazies, Part 2 and Car Crazies, Part 3). I was never a fan of these cars until my Dad gave me a 1996 EL Falcon ex taxi. I put in new 30mm lower springs and shocks and gave it to my wife to use a the daily shopping trolley. I couldn't believe it, but we kept that car until it reached 780,000km– yes, 780,000km. We then sold it for a reasonable price. This car had only had regular servicing in its life as a cab - two cylinder heads and two transmissions. When we had it, other than regular oil changes and replacing a temp sensor in the transmission, we had no problems with it. Just goes to show the longevity of some of these cars when treated right.

Robert Williams

Re AutoSpeed Falc #2

Re Car Crazies, Part 3 - The EF Falcon - I’m glad you got the Falcon, but IMO if you want to turbocharge it the BTR four-speed is heaps stronger and better (with a few simple shift mods).Check out

Tony Goodlich

How to Boost a VNT

Re: Boosted VNT? Response...

Dealing with boost control on a VNT is somewhat of a problem. The VNT’s variable vanes are moved by vacuum actuators (together with a vacuum pump), which are controlled by the engine management. This is why a traditional boost controller is not applicable - there is simply nothing to bleed. Bleeding the vacuum in the hose on the actuator will only make the boost lower. If the boost controller could send MORE vacuum into the actuator, the boost will increase - but the original engine management system will most likely throw codes if the boost has increased or decreased more/less than the map tells it to.

My opinion? Adding a boost controller to a VNT isn't worth doing - the best way to increase boost is via the original map in the engine management system.

Anders Damkjær
Fiat Club Denmark

Overlooked Centura?

In your articles 'Small cars with big cubes' Small Cars with Big Cubes - Part One and Small Cars with Big Cubes - Part Two you not only left out the Cortina and Capri - as mentioned by another writer - you left out the Chrysler Centura.

Don Sutton

Yes, the mighty 4-litre Centura is certainly a candidate - but not quite up with the monster 4.2 and 5-litre V8 Toranas of the time.

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