Miatapower List Archive

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Mail From: Chuck Traubman <(email redacted)>

My .02,

A couple of years ago a gentleman raced his 90 Miata with Turbo(not sure
which turbo) with the NNJR Porsche club. Being he had a non-Porsche he
had to participate in the X -class. His times were very impressive. As a
matter of fact he had some of the best times of the day.

Granted, our course is large. We use the large lot at Giants Stadium so
he can get on boost pretty well. The only problem is that when negotiating
a cone he and the 944 Turbo's tend to lose their rear ends if they boost hits
hard upon completion of turn.

Where speed mattered on the course, between cones at a distance, the
turbo seemed to really make a difference for him. It was in the tight spots
where he got sideways. My point, what the heck are you guys racing against
that makes a turbo car so uncompetetive? The X class had everything from
Miatas, Corvettes, Supra's, 240Z's, NSX's, Vipers, Integra's and Civic Si's.
Some of which were SCCA prepared. The Miata beat all of them and some
of the improved Porsches.

Chuck T
94 MX5
91 964 C2

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Mail From: Jim Creer <(email redacted)>

Greetings.

Am not competitive with my turbo. In two clubs I run EM and in one as SM.
Usually beaten by the BS and CSP Miatas on the clock, and really get buried
by the PAX. In one instance, lost boost in mid course and finished 3
seconds faster than my other runs. In fun runs I can beat my best turbo
times in a stock Miata with street tires. Do fairly well on the fast
courses but poorly on the short tight ones.

Think losing lots of time after apex..have to feather out of turns till the
wheels are straight. Spend a lot of time going sideways. The winning
Miatas seem to have only time invested in driver training and money
invested in tires. Any other changes are weak in comparison.

Jim Creer

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Mail From: "Shiv S. Pathak" <(email redacted)>

Jim Creer wrote:
>
> Greetings.
>
> Am not competitive with my turbo. In two clubs I run EM and in one as SM.
> Usually beaten by the BS and CSP Miatas on the clock, and really get buried
> by the PAX. In one instance, lost boost in mid course and finished 3
> seconds faster than my other runs. In fun runs I can beat my best turbo
> times in a stock Miata with street tires. Do fairly well on the fast
> courses but poorly on the short tight ones.
>
> Think losing lots of time after apex..have to feather out of turns till the
> wheels are straight. Spend a lot of time going sideways. The winning
> Miatas seem to have only time invested in driver training and money
> invested in tires. Any other changes are weak in comparison.
>
> Jim Creer

As with any change that increases the performance envelope of a car, the
driver must adapt. Nothing is inherently wrong with a decently tuned
turbo miata on an autox, track, street, etc,. Some turbo systems, of
course, are easier to drive than others. A turbo which spools up early
is easier should be easier to drive than one which comes on like a demon
at 4500rpm. In either case, however, the car the rarely the real
limitation. If turbo powerplants were so bad on the autox, a third gen
RX-7 wouldn't do so well. It's even got two of 'em.

Shiv

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Mail From: Bob Circle <(email redacted)>

Jim Creer wrote:

> Greetings.
>
> Am not competitive with my turbo. In two clubs I run EM and in one as SM.
> Usually beaten by the BS and CSP Miatas on the clock, and really get buried
> by the PAX. In one instance, lost boost in mid course and finished 3
> seconds faster than my other runs. In fun runs I can beat my best turbo
> times in a stock Miata with street tires. Do fairly well on the fast
> courses but poorly on the short tight ones.
>
> Think losing lots of time after apex..have to feather out of turns till the
> wheels are straight. Spend a lot of time going sideways. The winning
> Miatas seem to have only time invested in driver training and money
> invested in tires. Any other changes are weak in comparison.
>
> Jim Creer

I wonder if you could set your max boost to 3 psi and put on a set of
r-compound tires that might be a better set-up. BTW my car with a limited slip
diff will push a lot in 1st and 2nd gear, but is neutral in 3rd.

This read-only message was archived from a public mail list.
Mail From: (email redacted)




Following up on this thread -

Let's ignore Autox class for the moment. I seem to get the distinct
impression that a NA Miata will beat a "turbo" car. The reason being
"slow" spool up ?

If we talk about an ideal tuned F/I Miata for autox, again ignoring class -
how about an Aerodyne set to 3 - 4 psi max boost but tuned for the quickest
spool up time/ max boost achieved in smallest rpm possible. Is there such
a thing as to torque-ie?

Of course this is assuming appropriate skilled drivers : )






"Shiv S. Pathak" <(email redacted)> on 01/26/99 12:12:35 PM

Please respond to "Shiv S. Pathak" <(email redacted)>

To: Jim Creer <(email redacted)>
cc: (email redacted) (bcc: Dan W Thorpe/WLGORE)
Subject: Re: don't autox a turbo





Jim Creer wrote:
>
> Greetings.
>
> Am not competitive with my turbo. In two clubs I run EM and in one as
SM.
> Usually beaten by the BS and CSP Miatas on the clock, and really get
buried
> by the PAX. In one instance, lost boost in mid course and finished 3
> seconds faster than my other runs. In fun runs I can beat my best turbo
> times in a stock Miata with street tires. Do fairly well on the fast
> courses but poorly on the short tight ones.
>
> Think losing lots of time after apex..have to feather out of turns till
the
> wheels are straight. Spend a lot of time going sideways. The winning
> Miatas seem to have only time invested in driver training and money
> invested in tires. Any other changes are weak in comparison.
>
> Jim Creer

As with any change that increases the performance envelope of a car, the
driver must adapt. Nothing is inherently wrong with a decently tuned
turbo miata on an autox, track, street, etc,. Some turbo systems, of
course, are easier to drive than others. A turbo which spools up early
is easier should be easier to drive than one which comes on like a demon
at 4500rpm. In either case, however, the car the rarely the real
limitation. If turbo powerplants were so bad on the autox, a third gen
RX-7 wouldn't do so well. It's even got two of 'em.

Shiv

This read-only message was archived from a public mail list.
Mail From: "badger" <(email redacted)>


> If turbo powerplants were so bad on the autox, a third gen
> RX-7 wouldn't do so well. It's even got two of 'em.
>
> Shiv

In AS where the Rx-7tt runs against the Vette, it is important for the =
Rx-7tt
driver to know when the second turbo kicks in. Not respecting that littl=
e
bit of "information" can have tricky consequences.

FTD in the SFR SCCA a/x is sometimes taken by a BS Miata (Kevin McCormick=
),
especially if the course is at lunar like 3Com park. But, since that cou=
rse is so bumpy,
cars like the open-wheeled 13B powered Ralt of Mike Lella can't run due =
to ride hight
problems.

Eric Schwarzentraub
'91 Silver
Modesto,CA

This read-only message was archived from a public mail list.
Mail From: "Shiv S. Pathak" <(email redacted)>

Jim Creer wrote:
>
> Greetings
>
> Not sure "slow" spool up applies much to the Aerodyne at 8 PSI. Ran this
> Miata for at least 50 AutoX events. This does not mean I am a skilled
> driver but donate a lot of money to the clubs and wear out a lot of tires.
> May be a little gun shy after several experiences of modifying the course.
>
> If someone would advise how to temporarily and simply knock boost down to a
> few PSI, would try it next event. Restriction in the actuator line? Help
> please.

This is one reason my brother took out his aerodyne and installed a conventional
garret. Even at only 6psi, both of us didn't like the response of the turbo. It was
quick to spool up, for sure. However, it seemed like it was all or nothing and very
little in between. A higher boost levels (which we never attempted), it would be even
worse. Like everything in life, this one aspect can be improved as people on the list
have done by playing around with boost controllers and actuators.

Shiv

This read-only message was archived from a public mail list.
Mail From: Jim Creer <(email redacted)>

Greetings

Not sure "slow" spool up applies much to the Aerodyne at 8 PSI. Ran this
Miata for at least 50 AutoX events. This does not mean I am a skilled
driver but donate a lot of money to the clubs and wear out a lot of tires.
May be a little gun shy after several experiences of modifying the course.

If someone would advise how to temporarily and simply knock boost down to a
few PSI, would try it next event. Restriction in the actuator line? Help
please.

Frequently we swap cars for some fun runs. Have had only one other Miata
driver beat my best time by a fraction of a second. In all instances of
trying their BS/CSP Miatas, have beaten my turboed runs. Think this is due
to being able to hammer it out of the turns. The N/A Miatas feel sluggish
as hell but is not indicated on the clock.

There are other turbo cars there that turn in very fast
times...ie..Eclipse, RX-7, MR-2, and 300ZX.

Maybe it is time for a new hobby.

Jim Creer


At 19:54 1/26/99 -0500, (email redacted) wrote:
>
>Following up on this thread -
>
>Let's ignore Autox class for the moment. I seem to get the distinct
>impression that a NA Miata will beat a "turbo" car. The reason being
>"slow" spool up ?
>
>If we talk about an ideal tuned F/I Miata for autox, again ignoring class -
>how about an Aerodyne set to 3 - 4 psi max boost but tuned for the quickest
>spool up time/ max boost achieved in smallest rpm possible. Is there such
>a thing as to torque-ie?
>
>Of course this is assuming appropriate skilled drivers : )
>
>Jim Creer wrote:
>>
>> Greetings.
>>
>> Am not competitive with my turbo. In two clubs I run EM and in one as
>SM.
>> Usually beaten by the BS and CSP Miatas on the clock, and really get
>buried
>> by the PAX. In one instance, lost boost in mid course and finished 3
>> seconds faster than my other runs. In fun runs I can beat my best turbo
>> times in a stock Miata with street tires. Do fairly well on the fast
>> courses but poorly on the short tight ones.
>>
>> Think losing lots of time after apex..have to feather out of turns till
>the
>> wheels are straight. Spend a lot of time going sideways. The winning
>> Miatas seem to have only time invested in driver training and money
>> invested in tires. Any other changes are weak in comparison.
>>
>> Jim Creer
>
>As with any change that increases the performance envelope of a car, the
>driver must adapt. Nothing is inherently wrong with a decently tuned
>turbo miata on an autox, track, street, etc,. Some turbo systems, of
>course, are easier to drive than others. A turbo which spools up early
>is easier should be easier to drive than one which comes on like a demon
>at 4500rpm. In either case, however, the car the rarely the real
>limitation. If turbo powerplants were so bad on the autox, a third gen
>RX-7 wouldn't do so well. It's even got two of 'em.
>
>Shiv

This read-only message was archived from a public mail list.
Mail From: Craig Boyle <(email redacted)>

Put simply, low end torque is more important than high end horsepower in an
autox.

Of course turbo's aren't inherently bad, but aftermarket turbos are heavily
penalized by SCCA rules.

The RX-7 has dominated SS in recent years, but the Corvettes (last useful
model year 96) and RX7 (93) are falling apart. The opportunity is there for
Mazda to produce something new, especially since Chevy blew it with the
lame-duck C5 Vette.

Craig

> -----Original Message-----
> From: Shiv S. Pathak [SMTP:(email redacted)]
> Sent: Tuesday, January 26, 1999 9:13 AM
> To: Jim Creer
> Cc: (email redacted)
> Subject: Re: don't autox a turbo
>
[Craig Boyle] ... > Jim Creer

> As with any change that increases the performance envelope of a car, the
> driver must adapt. Nothing is inherently wrong with a decently tuned
> turbo miata on an autox, track, street, etc,. Some turbo systems, of
> course, are easier to drive than others. A turbo which spools up early
> is easier should be easier to drive than one which comes on like a demon
> at 4500rpm. In either case, however, the car the rarely the real
> limitation. If turbo powerplants were so bad on the autox, a third gen
> RX-7 wouldn't do so well. It's even got two of 'em.
>
> Shiv

This read-only message was archived from a public mail list.
Mail From: "Ralph Alder" <(email redacted)>

-----Original Message-----
From: Jim Creer <(email redacted)>
To: (email redacted) <(email redacted)>
Date: Wednesday, January 27, 1999 11:24
Subject: Re: don't autox a turbo


>
>Greetings
>
>Not sure "slow" spool up applies much to the Aerodyne at 8 PSI. Ran this
>Miata for at least 50 AutoX events. This does not mean I am a skilled
>driver but donate a lot of money to the clubs and wear out a lot of tires.
>May be a little gun shy after several experiences of modifying the course.
>
>If someone would advise how to temporarily and simply knock boost down to a
>few PSI, would try it next event. Restriction in the actuator line? Help
>please.
>

Jim,

One of the pluses of the Aerodyne, which I discovered after driving it for 2
years, is that the "attack", or boost rise rate, for lack of better term, is
adjustable. It is the only screw on the vane actuator. If your Aerodyne is
of recent vintage, ie: actuator pointing up, adjustment is simplicity
itself. IIRC, turning the screw clockwise, IN, will produce a slower boost
rise. Turning it CCW, will have the opposite effect. Try 1/4 to 1/2 turn
at a time until it's the way you like it.

I drove my turbo for a long time not really liking the way the boost would
build too fast for just a little throttle input. I was told that it could
be adjusted but I have a 3 yrs old turbo and they parked the actuator down
in the black hole of Calcutta, next to the block and under just about
everything. It can be gotten to but not especially easily (by this I mean
wait until the engine has cooled or jack the up front and go at it from
below). I've got it set now so it is slower in making boost but I can go
into the hills without going from 10 inches vacuum to 2 lbs boost with
nothing in between. I think that even in this slowed down mode it makes
boost quicker than "normal" turbos I've driven. I've also been told that
screwing the adjustment all the way in will make it slow in "attack" and
only make about 2-3 lbs boost. Can't verify that because adjustment issues
above.

I think Aerodyne is lax for not informing owners of this capability. Maybe
Shiv or Yatish would have a 300 hp Aerodyne if they had known about that. I
think a programable digital VATN actuator would be killer. Adjust the rate
of boost rise any way you want it for any condition.

Now, if I had a Torsen and a clutch and some tires....

Ralph Alder
Tustin, CA
'90 Classic Red w/Yellow Stripes
Team Aerodyne

This read-only message was archived from a public mail list.
Mail From: (email redacted)

In a message dated 1/27/99 7:35:52 PM Eastern Standard Time,
(email redacted) writes:

> I've also been told that
> screwing the adjustment all the way in will make it slow in "attack" and
> only make about 2-3 lbs boost. Can't verify that because adjustment issues
> above.

I tried it once and the result was "no" boost. It still made some of the
normal Aerodyne turbo noise but no boost.

FWIW,
Lee Bohon
'91 Aerocharger Stage I

This read-only message was archived from a public mail list.
Mail From: (email redacted)

In a message dated 1/27/99 9:05:47 PM Eastern Standard Time,
(email redacted) writes:

<<
> I've also been told that
> screwing the adjustment all the way in will make it slow in "attack" and
> only make about 2-3 lbs boost. Can't verify that because adjustment
issues
> above.

I tried it once and the result was "no" boost. It still made some of the
normal Aerodyne turbo noise but no boost.

FWIW,
Lee Bohon
'91 Aerocharger Stage I >>

Adjusting the rate of gain control does in fact seem to limit boost. It is
possible, at least on my car, to set it up such that the boost rise is so
gradual that it will max out at about 3-4 psi.......kinda like a 930 with no
topend.....:)

Gibb Phenegar
92 1.8 TEC-II

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Mail From: Jim Creer <(email redacted)>

Greetings:

Thanks for all the responses. My original question was on a method to
temporarily reduce Aerodyne boost for autox. Intend to tinker will all
suggestions. Corky Bell indicated a controlled leak in the vac/pressure
signal line would eliminate boost or allow downward adjustment.

Thinking about a little "rectifier" device made with check valves and an
adjustable bleed valve. Am going to do this with a cockpit control. My
"Old School" thinking says to make vacuum lines as short as possible. Any
harm in extending this line into the cockpit area ?

Thanks again to those that responded and a special thanks to those that set
this list up and maintain it. After 4 years of tinkering, this list is my
first opportunity to share experiences and ask questions.

Jim Creer