[Shotimes] New +20 cam dyno results

[Dave Pillsbury]

As I recall with the plus 20 and 40 cams. They were ground .055 then a 
.055 lash cap added and maintained the stock lift Basically they played 
with the duration and overlap of the cam and moved the power curve up in 
the RPM band and flattened the Torque curve. Which for a track car would 
probably be acceptable. But for street use not so great. I'm playing 
around with some cam profiles moving the torque curve around and getting 
more grunt lower. Details to follow after a few more dyno runs.
Dave



Donald Mallinson wrote:

> 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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