[TR] TR4A Piston Upgrade

Andrew Uprichard auprichard at comcast.net
Sat Sep 6 17:22:22 MDT 2008


By too much you mean something downstream will fail as the result of the
additional HP ?  I put 89s in my TR3a with a slightly modified cam, but
otherwise all is standard and I have had 4 years of trouble-free fun.

Someone much smarter than me can probably tell you how that 3mm translates:
the closest I cam come is to inform the group that blood flow to an organ
(in most or our cases the coronary arteries supplying the heart is the most
relevant) is related to the radius of the artery to the fourth power.  If
the same holds true in the internal combustion engine, that 3mm may
translate into a lot of additional horses.

Andrew Uprichard

-----Original Message-----
From: triumphs-bounces+auprichard=comcast.net at autox.team.net
[mailto:triumphs-bounces+auprichard=comcast.net at autox.team.net] On Behalf Of
Pat Caffrey
Sent: Saturday, September 06, 2008 6:32 PM
To: triumphs at autox.team.net
Subject: [TR] TR4A Piston Upgrade

Hello, 

I'm having an engine rebuild on my 1967 TR4A and am considering upgrading
the pistons to either 87mm or 89mm. The car is strictly for street driving.
I'd like to get more power out of the engine but fear 89mm may be too much.
Still, 89mm is only 3mm bigger than the stock 86mm pistons. Any thoughts on
which direction I should go? 87mm or 89mm? 

Thank you, 

Pat 
This list supported in part by the Vintage Triumph Register
http://www.vtr.org


Triumphs at autox.team.net
http://autox.team.net/mailman/listinfo/triumphs

You are subscribed as auprichard at comcast.net

http://www.team.net/archive


More information about the Triumphs mailing list