Boost Controllers v Boost Controllers
Could you tell me the
differences between a "gated" boost controller (Turbosmart) and the GFB Atomic
Boost controller? Which is better for low rpm boost and reduced lag? Do
electronic controllers basically work the same way as the bleed valves?
David Tenace
Australia
According to
their website, the GFB boost controller doesn't appear to be gated like the
Turbosmart item. An un-gated controller is unlikely to build boost as quickly as
a gated variant.
An electronic controlled system works
on the same concept (ie it bleeds air from the wastegate line) but electronic
control allows more precise control over boost pressure..
Check out
e-Boost Evaluation
,
Low Buck Boost
,
Project EXA - Part 3 - DIY Boost Control.
,
The Audi's DIY Boost Control - Part 1
and
Bumped Up Boost
for related information.
Gave Up Too
Soon?
Fantastic
article on the Peltier Intercooler Water Spray
but I think you gave
up TOO SOON. I wonder if the answer
was lying right under your nose - the hint appeared in the article itself. As
you say, the heat transfer to air through the external heatsink is insufficient.
Why not transfer heat to a second, larger
water store?! There will still be a small efficiency loss but a larger
water volume and larger heatsink should balance this out. This could be a static
store of larger volume in a metal container to maximise heat transfer out. By
using a larger volume of water, the temperature rise in this store for a given
measure of heat transfer will be minimised. The trick, I imagine, will be
balancing the benefits vs the weight and volume of the system.
One question
before going any further with development: Is there a benefit gained in
intercooler function with cooler water spray temperatures?
Michael Linton
Australia
Interesting idea, but it
raises the problem of then needing to cool the water. This adds even more
weight, complexity and cost. Re the benefit of using a cooled intercooler water
spray, we know the theory, but - since we were unable to go ahead with our own
on-car testing - we can't give you a definite answer.
Epic
Error
Re
your Aussie Engine Epic
2004 Engine Epic - Aussie Engines
- quite an informative article overall, except for a glaring error regarding the
5.4-litre 4V engine, as used in XR8 and GT. I'll quote:
”The first
bent-eight engine we must tell you about is the all-alloy, DOHC, 4-valve per
cylinder, 5.4-litre XR beast. In its ultimate 290kW guise (fitted to the BA GT
and GT-P), the Boss 290 engine uses a balanced forged steel crank, revised rods
and domed pistons to achieve a 10.5:1 compression ratio. Each of the VCT quad-
camshafts has a pretty aggressive profile and the intake arrangement is a beauty
- tuned-length trumpets, a large cast alloy plenum, 75mm throttle body and a low
restriction airbox. It's no wonder 290kW and 510Nm are on tap!”
The quad-cam 5.4 V8s are NOT VCT. They are the only engines in our current
range not featuring VCT. I hope this clarifies any misunderstanding! Thanks, as
usual, for the interesting cross-section of articles!
Tyrone Smith
Australia
You're absolutely right. Article now
corrected.
Damn
Drone
I
drive a '96 Nissan S14 200SX with 12 psi boost, K&N pod filter and a 3-inch
mandrel exhaust. My problem is that I can't find the right compromise between
noise and power. The exhaust system runs from the turbo, through two small
mufflers and then to a quite large offset muffler at the rear. The diameter of
the exhaust remains constant throughout the system. I have tried replacing the
rear muffler with a reverse flow unit - but it just kills the power. I did quite
a bit of reading on your site and found that maybe I should add a fourth muffler
to the system (due to the fact that I do not run a cat converter, as it is not
required here).
Should I try adding the original cat converter into the system? All I want to
achieve is remove the drone form the car. I've been to most of the good exhaust
shops in the area and they have no experience on my vehicle. Any help or
suggestions would be greatly appreciated. Your site is the best auto resource I
can find to date - thanks for the great mag.
Gordon Pieterse
South Africa
Try fitting a high-flow cat
and/or larger-bodied mufflers - these will take out more noise and drone. Also,
note that long, straight lengths of pipe tend to cause drones and resonances.
Rich Rex
My '94 Subaru WRX is running very rich fuel mixtures - 11.2:1 at idle and
10.2:1 at full power. I'd like to plumb a bleed valve into the fuel pressure
line as seen at Mixture Modifier
Two
questions... Which line coming out of the WRX manifold should I use? Can a
TurboSmart bleed valve be used since I want to lean it out all through the rev
range?
Scott Akins-Sellar
New
Zealand
Assuming your WRX runs the standard
management system, air-fuel ratios should be arund 14.7:1 at idle - this
is a function of its closed-loop fuelling. Based on what we've seen on WRXs
(including our own) it's normal to see high load mixtures in the 10s with an
engine that’s slightly modified.
We’d strongly suggest using the
dedicated Mixture Modifier – not a boost controller - to lean out the mixtures
when the engine is running in open-loop (at high load). The Mixture Modifier
features an adjustable set point and is designed exclusively for that purpose.
If you’re unsure about
which hose to insert the Mixture Modifier we suggest buying a factory workshop
manual - or take the car to somebody with WRX experience.
Note that we'll be covering a new electronic interceptor soon. This will
allow you to adjust mixtures - and ignition timing - by altering the output of
the airflow meter. The unit has
been designed by Silicon Chip magazine - stay tuned for our coverage!
SR20 Turbo Down but Not
Out!
Contrary to your comments in
the recent "Nissan SR-Series Engines" article
The Nissan SR-Series Engines
the SR-series engine is actually still in production. The Japanese Domestic
Market Nissan X-Trail uses a NEO VVL version of SR20VET developing 206kW and
309Nm - and it meets current Japanese emission standards.
Kevin Kwan
Australia
You're right. Thank you very much for
revealing that!
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