[Fot] TR4 head flow rates

[J.C. Hassall]

On 10/28/2010 9:56 AM, toodamnfunky at comcast.net wrote:
> FoT,
>
> Does anyone have any TR-4 head flow data. I'm thinking of going to the big valves
>
> so I decided it's time to get smart on the subject.
>    
Jim, unfortunately I have no way to measure CFM, but here is some 
anecdotal data.  In my TR4's previous build I had an Isky 777 cam, 
ported head (1.5" intake all the way to the seat), polished exhausts, 
standard valves and dual 40 DCOEs.  At 1000 idle I could easily hold my 
hand right at the tail pipe.  I had Isky reduce the duration on the 777 
to come on the cam at 3K instead of 3.5K (I think the grind is GM-72, 
can find that if you need it) and I used BFE's oversize valves (which 
are gas-flowed, and a work of art - I hated to get them dirty) on intake 
and exhaust.  Same head and carbs.  Now I can't hold my hand closer than 
about 8-10".  At idle (1K) the exhaust will vigorously flap my jeans leg 
from 3' away.

This is clearly not scientific but I'm very impressed w/Ken's valves.  
The engine pumps a *lot* more air than with the standard valves.  Ken 
may have flow data, I didn't think to ask him at the time.

hth

jim
>
>
> > From TeriAnn's website discussing webers.
>
> "optimum gas speed" for best flow was 325 fps.
>
>
>
> "this might explain a little why lots of times increasing the size of the inlet valves does
>
> NOTHING for the power and may even be a deterrent."
>
>
>
> I use the mikuni hsr45 smooth bores which flow at 237 CFM.
>
> I'm just trying to put things into some perspective.
>
>
>
> Jim G.
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe: http://autox.team.net/mailman/options/fot/jhassall@blacksburg.net
>
>
>
>    


-- 
Jim Hassall
Blacksburg VA
'63 TR4 in autox preparation
99% finished, 90% to go