DD2000 Cam - Feasible?
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,146
Likes: 0
From: Milford NH
DD2000 Cam - Feasible?
I have been playing around with DD2000, trying to get a nice flat torque curve on a fuel injected 355. I am leaning towards a TPI unit, there plenty out there, plenty of parts and plenty of people (GM dealerships) that can work on them. Anyways, DD2000, came up with the following cam, massive split-durations! Here are the specs:
113 Lobe Separation
109 Intake
188*/236* duration @ 0.05 lift
0.499/0.525 Lift @ Valve.
-15 IVO / 23 IVC / 55 EVO / 1 EVC
Is this a feasible cam? Do these numbers look correct?
RPM TQ VE %
2000 422 91.3
2500 444 94.3
3000 455 95.4
3500 444 96.9
4000 442 98.5
4500 430 97.6
5000 411 96.2
5500 382 93.2
I used a hydraulic lifter in DD2000, but in real life I think it would be a custom ground Hydraulic roller.
Here are the DD2000 inputs:
355 cu in.
AFR 180 flow numbers
10:1 compression
TPI w/ 1,000 CFM
Small Tube Headers w/ open exhaust.
I shift at 4,000 RPM usually and cruise around 2,500 RPM.
Thoughts?
[Modified by 69stingray, 8:39 PM 11/23/2003]
113 Lobe Separation
109 Intake
188*/236* duration @ 0.05 lift
0.499/0.525 Lift @ Valve.
-15 IVO / 23 IVC / 55 EVO / 1 EVC
Is this a feasible cam? Do these numbers look correct?
RPM TQ VE %
2000 422 91.3
2500 444 94.3
3000 455 95.4
3500 444 96.9
4000 442 98.5
4500 430 97.6
5000 411 96.2
5500 382 93.2
I used a hydraulic lifter in DD2000, but in real life I think it would be a custom ground Hydraulic roller.
Here are the DD2000 inputs:
355 cu in.
AFR 180 flow numbers
10:1 compression
TPI w/ 1,000 CFM
Small Tube Headers w/ open exhaust.
I shift at 4,000 RPM usually and cruise around 2,500 RPM.
Thoughts?
[Modified by 69stingray, 8:39 PM 11/23/2003]
Instructor
Joined: Mar 2002
Posts: 239
Likes: 0
From: Fredericksburg VA
Re: DD2000 Cam - Feasible? (69stingray)
Absolutely not. Desktop Dyno is not a camshaft design program. You will need to use a program like Dynomation that uses the entire cam lobe profiles, and models the entire intake and exhaust system to get accurate results. TPI performance cams are split the other way, especially with AFR heads and headers, or sometimes equal duration I/E with stock heads.
Melting Slicks
Joined: Feb 1999
Posts: 3,349
Likes: 1
From: Colorado
Re: DD2000 Cam - Feasible? (HeaderDesign.com)
:iagree:
Most of the time, you'll see about a 10 degree difference between intake and exhaust duration if it's a dual pattern cam. The purpose of a dual pattern cam is to increase exhaust scavenging when the head doesn't have enough exhaust to intake flow. But if you DO have good flowing heads and good exhaust, then SBC engines seem to respond well to symmetrical grind cams. Some dyno tests have shown the symmetrical cams to outperform the dual pattern cams in power and torque.
The cam you came up with had way too much difference between intake and exhaust.
DD2000 is a highly optimistic program. It's good to compare cams that are already available, but is pretty awful when trying to design your own cam. It also has some bugs. A 9,999 cfm carb, if even possible, would make your engine fall on its face, for example. But DD2000 shows it as only increasing in power and torque. Likewise, go into their turbo program and increase boost from 7 psi to 20 psi. That's an amazing increase in power, but the program gives it zero credit in the power and torque curves. So DD2000 is a fun toy, is moderately useful, but is too optimistic to be trusted in all conditions.
Most of the time, you'll see about a 10 degree difference between intake and exhaust duration if it's a dual pattern cam. The purpose of a dual pattern cam is to increase exhaust scavenging when the head doesn't have enough exhaust to intake flow. But if you DO have good flowing heads and good exhaust, then SBC engines seem to respond well to symmetrical grind cams. Some dyno tests have shown the symmetrical cams to outperform the dual pattern cams in power and torque.
The cam you came up with had way too much difference between intake and exhaust.
DD2000 is a highly optimistic program. It's good to compare cams that are already available, but is pretty awful when trying to design your own cam. It also has some bugs. A 9,999 cfm carb, if even possible, would make your engine fall on its face, for example. But DD2000 shows it as only increasing in power and torque. Likewise, go into their turbo program and increase boost from 7 psi to 20 psi. That's an amazing increase in power, but the program gives it zero credit in the power and torque curves. So DD2000 is a fun toy, is moderately useful, but is too optimistic to be trusted in all conditions.
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,146
Likes: 0
From: Milford NH
Re: DD2000 Cam - Feasible? (Bearcat)
... then SBC engines seem to respond well to symmetrical grind cams. Some dyno tests have shown the symmetrical cams to outperform the dual pattern cams in power and torque.
Is this cam even feasible? Why wouldn't it be? How would the engine and perform?
