Auto trans engines

Euen · Post by **Euen** » Thu Jan 20, 2005 10:28 am

Hi all

Although not a club memeber I have been following the forum for a few months. I am currently planning a project car based on MX5 mechanicals and have a query regarding the engines used with automatic transmissions.

I understand that the "auto" engines are slightly "detuned" but have not seen any info on what has been done to reduce the power. Can anyone please tell me how this has been achieved.

Thanks
Euen

Grant · Post by **Grant** » Thu Jan 20, 2005 10:38 am

As far as I have been able to find out, the auto engine has different
pistons (deeper dish in the top of the piston) to reduce the compression
slightly so lowering the revs at which peak torque is produced. This is to
match the engine characteristics better to the torque sapping auto trans.

Grant

Grant · Post by **Grant** » Thu Jan 20, 2005 10:38 am

As far as I have been able to find out, the auto engine has different
pistons (deeper dish in the top of the piston) to reduce the compression
slightly so lowering the revs at which peak torque is produced. This is to
match the engine characteristics better to the torque sapping auto trans.

Grant

Badcat · Post by **Badcat** » Thu Jan 20, 2005 11:02 am

hey euen.
my first mx5 was an auto.
if i remember correctly, the cams and/or cam timing is also different on the
auto motor.
what are you building by the way?
ken

From: <euen.burke@xtra.co.nz>
Date: 2005/01/20 Thu AM 10:28:59 GMT+13:00
To: <mx5list@mx5club.org.nz>
Subject: Auto trans engines

Hi all

Although not a club memeber I have been following the forum for a few

months. I am currently planning a project car based on MX5 mechanicals and
have a query regarding the engines used with automatic transmissions.

I understand that the "auto" engines are slightly "detuned" but have not

seen any info on what has been done to reduce the power. Can anyone
please tell me how this has been achieved.

Thanks
Euen

ken newell

From jifjif@gmail.com Fri Apr 27 17:15:00 2007
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com;
h=received:message-id

from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:references;
b=UZF4ZqshXzcfFG2RMglhCy+d4i2d5FgxKZKWAK88J6xgRqUjd5xmA23URkqku+JMpsEiPbDrq24uq98gnY5DskG1zotQHrXnK3kPVRZWdGdizTonvYRKaK1+b+/KsR6Cgeh1yj4k/EYn9dfzHUWewVycOnBZpDwcjfzZz6CqW3c=
Date: Thu, 20 Jan 2005 11:41:28 +1300
From: ~Jeff~ <jifjif@gmail.com>
To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: Auto trans engines
In-Reply-To: <20050119212859.CAQM16943.pop2-rme.xtra.co.nz@210.86.15.137>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
References: <20050119212859.CAQM16943.pop2-rme.xtra.co.nz@210.86.15.137>
Precedence: list
Message-ID: <TzKh6B.A.8o.RdYMGB@L733>

only the 1600 auto engine is like this, IIRC the 1800 autos are the
same as the manual version.

... smells like forced induction to me!

On Thu, 20 Jan 2005 10:28:59 +1300, euen.burke@xtra.co.nz
<euen.burke@xtra.co.nz> wrote:
[...]

Badcat · Post by **Badcat** » Thu Jan 20, 2005 11:02 am

hey euen.
my first mx5 was an auto.
if i remember correctly, the cams and/or cam timing is also different on the
auto motor.
what are you building by the way?
ken

From: <euen.burke@xtra.co.nz>
Date: 2005/01/20 Thu AM 10:28:59 GMT+13:00
To: <mx5list@mx5club.org.nz>
Subject: Auto trans engines

Hi all

Although not a club memeber I have been following the forum for a few

months. I am currently planning a project car based on MX5 mechanicals and
have a query regarding the engines used with automatic transmissions.

I understand that the "auto" engines are slightly "detuned" but have not

seen any info on what has been done to reduce the power. Can anyone
please tell me how this has been achieved.

Thanks
Euen

ken newell

From jifjif@gmail.com Fri Apr 27 17:15:00 2007
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com;
h=received:message-id

from:reply-to:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:references;
b=UZF4ZqshXzcfFG2RMglhCy+d4i2d5FgxKZKWAK88J6xgRqUjd5xmA23URkqku+JMpsEiPbDrq24uq98gnY5DskG1zotQHrXnK3kPVRZWdGdizTonvYRKaK1+b+/KsR6Cgeh1yj4k/EYn9dfzHUWewVycOnBZpDwcjfzZz6CqW3c=
Date: Thu, 20 Jan 2005 11:41:28 +1300
From: ~Jeff~ <jifjif@gmail.com>
To: MX5List <mx5list@mx5club.org.nz>
Subject: Re: Auto trans engines
In-Reply-To: <20050119212859.CAQM16943.pop2-rme.xtra.co.nz@210.86.15.137>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
References: <20050119212859.CAQM16943.pop2-rme.xtra.co.nz@210.86.15.137>
Precedence: list
Message-ID: <TzKh6B.A.8o.RdYMGB@L733>

only the 1600 auto engine is like this, IIRC the 1800 autos are the
same as the manual version.

... smells like forced induction to me!

On Thu, 20 Jan 2005 10:28:59 +1300, euen.burke@xtra.co.nz
<euen.burke@xtra.co.nz> wrote:
[...]

sfhardman · Post by **sfhardman** » Thu Jan 20, 2005 12:15 pm

Hi Euen,

From memory on the 1600's the auto engines are 9.0:1 compression ratio and the

manuals are 9.5:1. You would need a new set of pistons to remedy this.

Is it an MG replica you're building or something else?

Simon

Quoting "euen.burke@xtra.co.nz" <euen.burke@xtra.co.nz>:

[...]

sfhardman · Post by **sfhardman** » Thu Jan 20, 2005 12:15 pm

Hi Euen,

From memory on the 1600's the auto engines are 9.0:1 compression ratio and the

manuals are 9.5:1. You would need a new set of pistons to remedy this.

Is it an MG replica you're building or something else?

Simon

Quoting "euen.burke@xtra.co.nz" <euen.burke@xtra.co.nz>:

[...]

Euen · Post by **Euen** » Thu Jan 20, 2005 2:32 pm

Thanks Grant, Ken, Simon and Jeff.

Sorry Jeff, no forced induction planned for this project. Planning for 1800 5 speed with maybe a few little tweaks.

Simon, you got it. For those who haven't seen it, check out http://www.sportscars.net.nz/

Thanks
Euen
[...]

Who is online