Desktop dyno
 

I was wondering if anyone out there is bored and would like to input this info for me. A friend is building a 540 and is wondering what kind of HP he will make.

N/A 540 8.75:1 cr
GM rectangular port heads
Team G
1050 Dominator
Hydralic roller
600" 235/248 @ 0.50" on a 114 c/l

Any recomendations on cams would be helpful. The owner has a 25 minute idle to the lake and will not go with dry exhaust so anything real radical won't work. He does have Stainless Marine exhuast with the water dumping around 18" from the elbow.

Thanks

sell him yours, but factory power, and run all day long with us on the BIG LAKE!!!

how's the recovery from the sledding incident.
is it fixed, wanna go first full weekend in April? then get the boats out 2 weeks later?

Hey Rob,
Unfortunatley my friend needs two !
Sleds are a sore subject (pun intended :D ) right now. I'm healing well... the bruise on my ass is just about gone. But the XCR 600 I sold is chapping my ass. The guy I sold it two melted two pistons the first time he took it out. He put 87octane in it, so we rebuilt it, put 94octane in it and he burned it down again. Now this sled has been fine since 96, myself and my girlfriend rode it last year with no problems. It's strange the plugs are a nice dark tan, so it doesn't seem lean. So I'm going to pay for the parts and we will try it again. I'm going to go thru everything...carbs, airbox, fuel lines etc. Then fatten the hell out of it.
And to top it off State Farm is investigating my claim on the other sled !:mad: They originally made me an offer (sled is totalled) and it was pretty low so I countered and the next call I got was from the investigation dept.
It looks like I'm sledless for the rest of the season.

595hp @5500rpm and 606tq @ 4500rpm

378hp and 567tq @ 3500rpm

These figures are with a Crane 741 hyd roller cam and open headers and I assumed the heads have some bowl/pocket port work, but not fully ported

I have a friend here on OSO "Doug" (Pure Adrenaline) who had his 540 cubed engines dyno'd with the Crane 741 cam and Dart heads like yours and he made 595hp @5500rpm. So it seems the Desk Top Dyno is accurate in this case.

Thanks Mark.
You used the stock Rec. ports right ?
And yes you are correct , there will be a slight amount of work done on them.

What are the specs on the Crane 741 ?

In the ball park...
 

Chuck, the only rectangle port heads they have in Desk Top Dyno are: fully ported and Pro Mods which in your friend's case are neither one of those. Desk Top does list several "oval port" configurations and I chose the "oval port w/large valves and pocket porting" for this test----I feel that is the closest I can come to his combination. Doug/"Pure Adrenaline" has the World Products cast iron small rectangle port 308cc heads that he had bowl ported by JimV ---nothing major at all.

I don't know what size Intake valve your friend is using, but I only used the stock size valve that normally comes in that head which is a 2.19". By just going to a 2.25" intake valve, the Desk Top shows an increase of an additional 9hp---604hp @5500rpm.

The specs on the Crane 741 cam are 236*/242* and they normaly come in a 112* lobe sep but can be ordered and ground on a 114*. Lift for this cam is .612"/.632"

BTW, on the Dest Top with your friend's combination using the 741 cam, going from 114* lobe seps to 112* lobe seps shows a 1hp DECREASE in power @5500rpm and another DECREASE of 6hp @3500rpm. Sounds like the 114* is a good choice in this case. A 114* lobe seperation is what I have on my cams.

Doug uses a dual plane intake manifold on his 540's which he needs for his heavy 35' Cigarette.

My 540's with a Holley 830cfm carb had the same cam specs as the Crane 741 and with aluminum Dart 310cc Pro-1 heads that were NOT fully ported but were given a little more than a pocket port at the time and made 630hp @5400rpm with about 9.2 comp ratio @34* and 622hp @5400rpm @32* advance.

So, I think your friend's engine is in the ball with these comparisons. :)

Mark/KAAMA

Thanks Mark,
On that 741 cam , can you still run stock lifters? I will try and talk him into going that way with the cam.
He will be happy with those numbers. It should make his 31 Scarab run pretty good !

BTW - Dan has Imco exhaust I believe, but it's still better than stock........

________________________________________
Kaama,
How did you get the comparisons of which head is best represented in the dyno? By the flow numbers ?

I didn't run it, but the numbers sound reasonable.

I don't think I can get in any closer than what I have already shown
 

Ratchet, the only thing I chose was what the options were that the Desk Top gave me---not flow numbers, but like I said; it had several different oval port options. I merely chose which one I thought came the closest to what Chuck's friend was running and it sounds reasonable to me because of my own 540's and Doug's 540's. I'm sure it's not far off---he's going to be right around 600hp @5500rpm or so.

Mark,
I just talked to my friend and it sounds like the engine builder (Lenny) ordered the cams last night.
They are very similar, about the same on the duration but lift is .587/.610 , I guess they are made by Crower.