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anyone have a engine dyno program

2K views 26 replies 7 participants last post by  jarrettandroski 
#1 ·
i was wondering if anyone had a dyno program and if they had any spare time or ambition to check a combo for me chevy 355 with afr 195cc street eliminator heads and a crane energizer cam with 286 adv duration and a gross lift of .465" with a edlebrock performer intake and eldlebrock 750 carb and hooker headers
 
#4 · (Edited)
You can guesstimate the squish depending on whether or not the block has been decked and what kind of piston you used, along with the compressed thickness of the gasket.

If you used a cheap, rebuilder type piston, then the piston compression height is probably around 1.540" and the squish will be in the toilet with a virgin, un-cut block and a standard 0.040" compressed gasket.

Add up the stack. Half the crank stroke is 1.740". The rod is 5.700". The piston is 1.540". This adds up to 8.980" Subtract this from a virgin block deck height of 9.025" and you get the piston down in the bore 0.045" at TDC. Add a standard 0.040" gasket to this and the squish (or lack of squish thereof) comes out to 0.085". If this is what you put together, chances are that the motor will detonate on pump gas at 10.0:1

If you used quality pistons that were manufactured with a piston compression height of 1.560" (or 1.561" in the case of KB hypers), then you may slide by with a squish of 0.065". If you used 1.560" pistons and a head gasket thinner than 0.040", you should be fine on pump gas.

As a side note, in my opinion, you did a good job of matching the cam to the c.r. You should also get a nice rump-rump out of it with the 106* LSA.
 
#8 ·
OK got the results.
I am not very familiar with chevy's but a 355 is a 350 bored 0.030" over, correct?
The results are valid for testing the engine on a dyno:
- No exhaust system
- Electric waterpump and fan

Dynamic compression: 7.72
Theoretical cranking compression: 192psi
Idle vacuum: 11,7" Hg


Info you minimally need for a decent result:
Block:
- bore x stroke
Head:
-flow for intake and exhaust
-valve sizes
-compression
-squish<0.060" yes/no
and preferably port lengths and diameters at faces
Intake:
-type of manifold
-cfm of carb
and preferably port lengths and diameters at faces
Exhaust:
-primary pipe diameter
-primary pipe length
Cam:
-type of cam
-open and closing events @0,050"
-cam lift
-rocker ratio
and further type of fuel if not gasoline
 

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#13 ·
Jarrett
Just a note. I think that he used a program called Engine Analyzer Pro. This is from Performance Trends. They have a "light" version for considerably less money, called simply Engine Analyzer. Desktop Dyno is an entirely different (and dare I say, IMHO less effective) program. I am not familiar with DynoSim advanced, as mentioned by TechInspector.

Pat
 
#14 ·
PatM said:
Jarrett
Just a note. I think that he used a program called Engine Analyzer Pro. This is from Performance Trends. They have a "light" version for considerably less money, called simply Engine Analyzer. Desktop Dyno is an entirely different (and dare I say, IMHO less effective) program. I am not familiar with DynoSim advanced, as mentioned by TechInspector.

Pat
Hi Pat, here's the rundown on DynoSim products. The one I bought is the fourth column from the left, headed up DynoSim Pro Tools....
http://www.proracingsim.com/enginesimfeaturetable.htm
 
#15 ·
Yep I used engine analyzer pro.
Sorry SBCfan04 I thought you were talking about desktop dyno specifically.

You can download a demo here for both the normal and pro version of engine analyzer.
http://www.performancetrends.com/download.htm#eapro
The demo's work for 10 days.

I have also used camquest and desktop dyno, but I think engine analyzer pro is alot better.
No experience with dynosim.
Just my 2Cents.
 
#16 ·
oh ok so engine analyzer is the way to go well if they have a free demo i will probabaly just use that for now as i was going to try a few crane saturday night special cams and some lunati voodoo cams thanks for all the help to everyone its my first engine im building and im just 18 working 2 jobs so i can afford to do it and i just want to do it right the first time cause i wont have enough to change it all again for a while
 
#17 ·
jarrettandroski said:
oh ok so engine analyzer is the way to go well if they have a free demo i will probabaly just use that for now as i was going to try a few crane saturday night special cams and some lunati voodoo cams thanks for all the help to everyone its my first engine im building and im just 18 working 2 jobs so i can afford to do it and i just want to do it right the first time cause i wont have enough to change it all again for a while
Sensible thinking young man. You'll do fine. :thumbup:
 
#23 ·
Jarret, I could if you want, e-mail you the analyzer file I used so you can experiment from there.

what do you mean by this:
"oh i c everything is from 2003 on there and the heads flow way better since then"
Your AFR heads?

By the way you can choose how much rpm points you want calculated and at what interval.
Are you using a cilinder head flow table?
 
#24 ·
yea last night when i was playing around with it i clicked the afr 195 street eliminator and was wondering why my dynos were alot lower then ones on the sight and from other people but then i seen the heads on the demo were from 2003 information and i updated the head flow data and it is working just as it should i believe.
 
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