[Shotimes] New +20 cam dyno results

[Adam Parrott]

Agreed with Dave.  Optimal A/F target for a cam'ed N/A motor should be 
around 12.5-13:1, depending on mods and target power range.  I believe that 
John H. and the others will echo my thoughts on this.

As for the torque loss itself, Don, I would have to side with Lee's 
thoughts on the cam timing.  As I'm sure you know, those who have gone the 
route of the +20's thus far have either hit their mark out-of-the-box or 
have needed additional tuning via adjustable sprockets.  Unfortunately, it 
would seem that you have fallen into the second category.  :)

EEC tuning (which is always beneficial, if nothing but for the learning 
experience) will likely help you net a few extra ponies; however, I 
wouldn't consider looking solely to an EEC recalibration as the source of 
your power gains, especially if you're looking to get back the extra torque 
you seem to have lost.  If it were me, I would consider purchasing and 
utilizing the adjustable sprockets in tandem with an EEC tuning tool so as 
to utilize the maximum benefit from your new cam setup.  One without the 
other, in this case, will only get you so far "down the path".

Something else to consider, should you ever decide to keep your new-found 
high-RPM HP up in it's existing range and/or take advantage of it while 
it's up there, is the ability to modify the factory rev limters so that you 
can take advantage of said high-RPM power.  This point alone would make 
moot your need for an EEC tuning tool (may I suggest a TwEECer?).  ;)

Guess it all depends on how much power you want to make and where.

Adam


----- Original Message ----- 
From: "Dave Kegel" <d.kegel@comcast.net>
To: "'Leigh Smith'" <leighsm@comcast.net>; <shotimes@autox.team.net>
Sent: Sunday, May 29, 2005 9:28 AM
Subject: RE: [Shotimes] New +20 cam dyno results


Leigh,

11.5-1 is really rich, not lean.

Dave

-----Original Message-----
From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
On Behalf Of Leigh Smith
Sent: Sunday, May 29, 2005 12:25 AM
To: Donald Mallinson; shotimes@autox.team.net
Subject: Re: [Shotimes] New +20 cam dyno results


Don;
It's the extra duration killing the torque. More specifically the increased
overlap. If you spread the cams out by advancing one and retarding the
other, I'd guess you could get most of the torque back, by decreasing the
overlap. Wider lobe centers don't hurt higher end hp too bad, and you do
need the torque. Then you could advance both of them together to shift the
power curve a little lower, or retard them both for higher. Of course,
adjustable timing gears would be required. But you have got so much more
tuning capability than a single cam motor. FWIW 11.5 sounds too lean, I'll
bet there is more power there too.  Have fun! Lee

----- Original Message ----- 
From: "Donald Mallinson" <dmall@mwonline.net>
To: <shotimes@autox.team.net>
Sent: Saturday, May 28, 2005 1:50 PM
Subject: [Shotimes] New +20 cam dyno results


> Just got back from the first dyno test of the '89 with the new setup.
> Here are the details:
>
> Previous tests:
> 205-207 hp at 6100 rpm
> 196 lb ft at 4800 rpm  and 190 @ 3100 rpm (before runners open)
> 180,000 miles on the car/engine now, test above done at probably
> 165,000 miles. Engine is healthy using about 1/2 quart per 3000 miles
> like it has since it was 45,000 miles young when I bought it.
>
> BOS basically, without a computer chip, running a Pro-Flo 77mm Maf.
> Walker exhaust with generic turbo mufflers.
>
> New:
> +.20 cams
> EH intake runners
> BBB
> new cam belt, plugs, wires, with NO computer chip or tuning, same
> setup otherwise as above.
>
> 220hp @ 6700 rpm
> 182.5 lb/ft @ both 3500  and 5500 rpm  Torque basically flat between
> these rpm's except for a slight dip when the runners open at 4000 rpm.
>
> Air/Fuel mixture is basically 13-1 from about 3700 to 5700 rpm and
> then has a slow drop to 11.5-1 at 7000 rpm.
>
> First, I am shocked at the loss in torque, this is the exact opposite
> of what I wanted.
>
> Second I am a bit disappointed in the HP gain, but maybe more is to be
> had with some computer tuning.
>
> So tuner guru's..... a couple questions:  Where did my torque go and
> will tuning get any of it back?  Is there more HP to be had?
>
> Don Mallinson
> _______________________________________________
> Shotimes mailing list
> Shotimes@autox.team.net http://www.team.net/mailman/listinfo/shotimes
_______________________________________________
Shotimes mailing list
Shotimes@autox.team.net http://www.team.net/mailman/listinfo/shotimes
_______________________________________________
Shotimes mailing list
Shotimes@autox.team.net
http://www.team.net/mailman/listinfo/shotimes