[Shotimes] New +20 cam dyno results

[Donald Mallinson]

Ron,

Correct me if I am wrong, but since these cams are just a regrind of 
stock cams, then the duration and overlap is basically the same, just 
lift effected.  From the profile I saw, and comparing to the stock cams, 
I don't think duration is any longer at all, with the exception that an 
increase in lift may cause the partial opening of the valves to be a bit 
sooner and later, but the tip profile would have to be wider than stock 
to effect much of anything else, and it doesn't look that way.

I was not impressed though that the cams did not come with a 
specification sheet.  Maybe Josh can make one available?

The reason I am not real happy with the loss of torque is that a couple 
other installations that I have seen have had slight increases, but no 
decreases.

I thought about doing adjustible sprockets, but if I had gotten the same 
results as the others I saw and was told about, I would really not think 
it would be necessary.  I don't think they had the adjustable sprockets.

Don Mallinson

Ron Porter wrote:

>Results look pretty good to me!!
>
>I have not been following anything on the new cams offered, nor any of their
>specs, but don't these cams increase duration & overlap? If that's the case,
>then what you are seeing is pretty typical for that kind of a cam mod in any
>kind of engine (OHC, OHV, etc).
>
>If you just increased lift, and left duration/overlap alone, you would have
>seen more gross torque throughout the range.
>
>Cam upgrades are one of those mods that can make nice gross HP numbers, but
>don't necessarily make the car feel any quicker as they shuffle the torque
>curve around (unless gearing changes are made).
>
>However, for a track car, having a nice, flat torque curve is a pretty
>desirable thing, as is having a nice, wide rpm range that develops power for
>those times that a gear change (with the stock cams) just comes at the wrong
>time on a track.
>
>Ron Porter
>
>-----Original Message-----
>From: shotimes-admin@autox.team.net [mailto:shotimes-admin@autox.team.net]
>On Behalf Of Donald Mallinson
>Sent: Saturday, May 28, 2005 1:51 PM
>To: shotimes@autox.team.net
>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
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