Rotary advice
Problem
I recently bought my friend’s ’86 Mazda
RX-7 GXL with a bridge-ported 13B S4 engine. I had heard that rotary engines
come turbo-ready, but just to make sure, I thought I would ask. Is it really as
easy as slapping the turbo on, or do the internals need to be swapped with
parts that will hold up against boost?
’86
Mazda RX-7 GXL
How to fix
On the street and even occasional drag
racing, you shouldn't have any issues boosting a normally aspirated rotary
engine. Aside from the higher compression ratio of a normally aspirated engine,
the NA engines use a slightly different coating on the rotor housings, have
weaker stationary gears, and a tad bit less oil pressure. The coating and gears
will only have durability issues in racing or sustained high rpm use. Whoever
built the bridge port engine probably already used a turbo oil pressure
regulator or shimmed the factory regulator.
Engine builders who build high-powered
turbo engines typically also like to run different apex seals. Ceramic apex
seals are unquestionably the strongest (and most expensive), but if you ask
five engine builders which non-ceramic apex seal they prefer to use, you'll
probably get five different answers. The factory seals can hold up to boost
fine also, but there’s les margin for error. The engine's life will be up to
the parts selection (i.e. good intercooler and radiator) and quality of ECU and
tuning with factory Mazda apex seals.
Regardless, you’ll want to remove the oil
pressure check spring and ball in the eccentric shaft and replace them with a
plug. This will add some reliability and ensure oil flow to the rotor bearings
as the ball and spring have been known to stick from time to time. Chances are
the engine builder who built the bridge port already addressed it, but just a
heads-up.
Since your buddy’s engine is a bridge port,
the power and torque curves will undoubtedly be a bit higher than a street
ported engine. After turbocharging you’ll find the power and torque peaks will
be lower than they were normally aspirated, which will be good for engine
longevity, of course.
Money hungry
Problem
My car is a ’08 Honda Fit that is almost
paid off! So I was thinking about doing something to the engine, either a
K20/K24 swap or something along those lines. I really wanted to do something no
one has done to the Fit yet, but I can’t come up with anything seeing that a
lot has already been used. Would you guys have suggestions on what to do? Where
should I start? I know once I walk into a shop they will see I’m a girl and
suck the money out of me.
’08
Honda Fit
How to fix
Usually doing a swap that nobody’s done
before also involves using more money. The reason is that there are not going
to be any off-the-shelf swap kits available and there won’t be any knowledge
base available for the other aspects of the swap (e.g. ECU wiring, axle
selection, shift linkages, and more). Somebody will need to figure it all out from
scratch and that will all go on your bill in most cases.
i-Vtec
engine
Aside from that, the K20/24 engines are
really good and hard to beat. You could drop an H22 in, but it really isn’t a
better engine. Sure you’d be different, but you’d end up with an older engine
that didn't make as much power with worse fuel consumption. Personally, I
don’t see any real value in that, but if that’s what you want to be different
at a car show or meet, then go ahead. Another different swap would be a 4G63
from an Evo or a B16/17/18/20.
As for the girl aspect of it, you could
easily use that to your advantage. You should know that guys do stupid things
for a big butt and a smile. Look at all the guys buying this magazine!
Safety first
Problem
I own a ’97 Talon TSi currently limited to
524 awhp on the Mustang dyno at FFTec in Hayward, CA, until I get a 5-bar map
sensor to replace my 3-bar and retune for more boost. I’d really like to run my
Talon at the track, but do not have a ’cage or harness bar for my four-point Takata
harnesses to mount. What ’cage would you recommend for it to still be
comfortable as a street car for me and a passenger, and be able to pass tech
for mid-10-second passes and have safe harness mounting points. Would a bolt-in
Auto power six or eight-point ’cage do the trick or is a weld-in custom ’cage
the better way to go?
’97
Talon TSi
How to fix
An Auto power roll bar isn’t sold as an
NHRA legal roll bar, but the NHRA rules pretty much just require a four-point
roll bar to be there as long as the car runs the quarter-mile between 10.00 and
10.99 seconds. The only provision to this rule is if the car goes faster than
135 mph, then the car will need a ’cage (really a bar with door bars). This
means a four-point Auto power roll bar will do the trick as long as your car is
slower than 10.00 seconds and under 135 mph. Of course, the bar keeps the car
the most comfortable.
Likewise, Auto power roll cages are not
NHRA legal roll cages. I believe they are sold as SCCA legal ’cages. The NHRA
rulebook states that door bars must be between the shoulders and elbows. So you
could conceivably install an Auto power four-point roll bar in the rear and
fabricate swinging/removable door bars. This will keep the car comfortable on
the street and legal for the strip. An experienced fabricator should be able to
do this for you cleanly although clean is seldom cheap.
