Engine Guys: What do I do?
Instructor
Joined: Mar 2010
Posts: 102
Likes: 0
From: Livingston TN
Sorry that I can't explain myself very well. When I suggested the cam in my earlier post, I only meant that the profile was in the ballpark off what he needed. the reasoning behind using Dyno2003 was to show comparison between an engine setup close to what could be used "with stock manifolds" VS. the same engine setup with small tube (1 5/8") headers. That is all.
Am I wrong for suggesting that the stock manifolds should be port matched and polished for best results without changing to a different manifold or header? Or that a set of headers will yield more hp/torque than stock manifolds?
As for saying that 10.55:1 compression is max for 87 octane... I will admit that I was wrong for stating that. Now in thought, I remember that it is max for 93 octane.
So does everyone disagree with the cam I suggested? Or for using Dyno2003?
I used Dyno2003 about 3 years ago for deciding what I would like to use when I built my "hotrod motor". With everything I selected, the program estimated 438 HP and 442 FT/LBs. The machineshop that I took my engine block to told me that a desktop dyno program will be accurate within 10 percent. Not bad I thought. I DO agree that the program is a little optimistic, so at worse, my engine setup could have as little as 394 HP and 398 FT/LBs. Not bad for wanting around 400 HP.
When I took my engine to a real engine dyno, it came out with 408 HP and 425 FT/LBs.
Close enough for me.
Is it bad to say that a desktop dyno program is ok to use when comparing different components? And when shooting for a "range" in horsepower and torque?
I'm done.
Am I wrong for suggesting that the stock manifolds should be port matched and polished for best results without changing to a different manifold or header? Or that a set of headers will yield more hp/torque than stock manifolds?
As for saying that 10.55:1 compression is max for 87 octane... I will admit that I was wrong for stating that. Now in thought, I remember that it is max for 93 octane.
So does everyone disagree with the cam I suggested? Or for using Dyno2003?
I used Dyno2003 about 3 years ago for deciding what I would like to use when I built my "hotrod motor". With everything I selected, the program estimated 438 HP and 442 FT/LBs. The machineshop that I took my engine block to told me that a desktop dyno program will be accurate within 10 percent. Not bad I thought. I DO agree that the program is a little optimistic, so at worse, my engine setup could have as little as 394 HP and 398 FT/LBs. Not bad for wanting around 400 HP.
When I took my engine to a real engine dyno, it came out with 408 HP and 425 FT/LBs.
Close enough for me.
Is it bad to say that a desktop dyno program is ok to use when comparing different components? And when shooting for a "range" in horsepower and torque?
I'm done.
Thread Starter
Advanced
Joined: Oct 2010
Posts: 56
Likes: 0
From: Lubbock TX
There definitely can be a lag, but smart tuning of the secondary opening and correct sizing of the carb virtually eliminates it.
If you're planning to manually shift the TH350, then a mechanical secondary carb will work...but when it's in "drive" you'll get less throttle response and overall poorer fuel economy.
There's no "right" answer here and either carb will work...it's a trade-off, like everything else
If you're planning to manually shift the TH350, then a mechanical secondary carb will work...but when it's in "drive" you'll get less throttle response and overall poorer fuel economy.
There's no "right" answer here and either carb will work...it's a trade-off, like everything else
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Hey, you're not bugging me - this is what the forum is for and why we're here
Yes; I have a forumla I use for this but in general for a warm 350 around 600-650 CFM is the right size.
Yes; I have a forumla I use for this but in general for a warm 350 around 600-650 CFM is the right size.
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Instructor
Joined: Mar 2010
Posts: 102
Likes: 0
From: Livingston TN
I understand that we disagree, but I'm not sure what we disagree on....
