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Some of this week's Letters to AutoSpeed!

22 June 2003

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BOV Or Not?

I've read your articles about blow-off valves and what I would like to know is, do they shortening the life of your engine or turbo? One of my friends tells me not to put in a blow-off valve simply because it will damage both the turbo and the engine. I would really like one and I am not sure when is the right time to put it in. My car is standard for now; I would like to modify it, but without shortening the life of the engine. Please tell me what you think. Thanks.


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That's a tough one to answer! We doubt whether an OE-type blow-off valve in the factory location would shorten the life of a turbo or engine - manufacturers wouldn't fit them if they caused any mechanical problems. On the other hand, we can't be absolutely sure about aftermarket valves (which can be adjusted to vent at a certain vacuum) mounted in a randomly selected location.

One of our greatest concerns about an atmospherically venting BOV, though, is it enables dust to enter the post-air filter inlet ducting and, later, the insides of your engine; make sure you fit a filter to the atmospheric side of the valve or, alternatively, route it back to the pre-compressor intake like the car manufacturers do.

Our advice - test a BOV on your car and, if it makes any improvement, we'd be inclined to run with it. If you can't feel any kind of gain, don't bother!

Who's Honest and Who's Not?

G'day. Firstly, I'd like to say that I think the new look is great. I especially like the fact that all articles are now dated, and, as before, I'm impressed with the high quality of diction and grammar - qualities that are becoming rare these days, especially on websites.

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Next, whilst I find the articles very informative, I get a little disappointed when the article highlights the integrity of a workshop that's (usually) in Adelaide. It's great that good, honest 'shops are getting promoted, but it doesn't really help those of us that don't live in the same city. Perhaps you could look at providing the names of shops in other states that are trusted and are familiar with the work being described in the articles. I have considered calling interstate shops from your articles to ask if they can recommend a shop in Sydney, as I think they'd probably know who's good and who's not. Whilst I understand that this isn't really what you do, I think this sort of 'support structure' of 'honest' workshops would be an invaluable service to your subscribers, particularly considering how many 'dodgy' workshops there are in this industry.

Keep up the great work!

Craig Brudenell

We're glad you like our new-and-improved format.

On the issue of where our stories are sourced... AutoSpeed currently has two major contributors - Michael Knowling and Julian Edgar, based in Adelaide and the Gold Coast respectively. As such, the majority of our workshop stories will be derived from our 'home towns', although note that we also venture throughout Australia on regular story collecting trips. In Sydney, for example, we have done many stories with workshops such as MRT, Silverwater Auto, TRP, Bavariacars, C&V Performance and more; by doing stories with these 'shops, we are effectively creating a "support structure" for them.

A compilation dedicated to Australia's "honest" workshops would surely upset a few proprietors that get left out and, well, we might get into some major legal trouble - regardless if we think they're honest or not...

Supercharged RB30!

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I have a Holden Commodore VL with a RB30E motor, which is pretty much stuffed. I also have a blower off a Toyota, which is not yet set up for the VL engine. Is it worth spending the money to get another RB30E and supercharging it? Where would I find information on how to do it?

Stephen Nicholls

Certainly, if you're going to supercharge, you need a good condition engine as the base; you won't make good power and you'll constantly be chasing your tail otherwise.

CAPA retail a kit for bolting the 1G supercharger onto the Holden V6 and, a long time ago, we drove a VL with one of their centrifugal blowers fitted so we imagine they would be able to help. CAPA can be contacted on +61 8 85 823 499 at visit their website at

Mira With More!

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Hi - I need some info on how to equip my car with a high performance exhaust system. Please assist me on the design and layout. It's a 1988 Daihatsu Mira L200, with engine code EF-JL.

Mohd Zaman

The appropriate exhaust system depends how much power you're aiming to achieve plus, of course, the amount of noise you'll be happy with.

Assuming the car is a standard naturally aspirated Mira, we'd suggest a pipe diameter of 1 3/4 - 2-inches should suffice, along with a 2-inch cat and the largest bodied straight-through rear muffler you can fit.

Also - as mentioned in "Lung Transplant" - this is an ideal example where OE cats and mufflers can be used to attain an excellent combination of noise, flow and cost.

1G Tuner?

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I read article 103 ("1G Gee-Gees") concerning a 1G-GTE engine which a garage called Racecraft did some modification work on. I was wondering if I could possibly get in contact with them via email. Or some detailed advice about modifying a 1G-GTE in terms of what pistons, camshafts, etc to use. Thanks in advance.

P.S. I have a Turbonetics T04B 62-1 'charger.

Navin Ragoo
Trinidad and Tobago

Alex from Racecraft (Melbourne, Australia) can be contacted on +61 3 9338 0550. Hope that helps!

Turbo Questions

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In one of your interviews, Brett Middleton said that anything over 16 psi in a WRX is dancing with danger, but ChipTorque are raising their boost levels to 18 psi peak with their WRX enhancement kit without the use of fuel rail modifications. Will this create a problem with one of the pistons?

My 180SX has a T25 and I have been told the life expectancy of that turbo on 15 psi is about six months. Are WRX turbos much more durable than my turbo? Are they even ball bearing? Sorry if I sound like an idiot...

Andrew Seward

Different workshops have different opinions of what is 'safe boost'. Furthermore, cars in different states often use different grade fuels and run in different conditions, so it's difficult to so say whose right and who isn't; one thing's for sure, though, the less boost required to produce a given power output the better!

As far as we're aware, the standard 180SX turbocharger uses a conventional sleeve bearing; it's the ceramic turbine impeller that's the problem. Under high boost pressures, the ceramic is prone to shatter, often making a mess of the whole turbocharger unit. On a 180, we'd like to see boost kept comfortably below 15 psi until we changed to a (stronger) steel turbine wheel.

And, no, you don't sound like an idiot...

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