need tips for dyno tune

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
Grumpy,
Please open this up to all readers if you would as I'm not sure how to add all members to the thread.
I'm planning to make a run to the local chassis dyno next week since I feel like I have all the bugs worked out of the Camaro.
The use of a dyno is new to me so I have a few questions.
Since I'm using EFI it is trivial to change AFR and am looking for input.
I plan to build 3 POWER tunes (12.5, 13.0 & 13.5 AFR) and try them all.
I know that higher AFR will help keep heat down but at some point I presume it looses its value. That is my KEY question...
how rich is too rich?
I am looking to make north of 500hp and torque. Based on reading detailed on your site, tools from Comp Cams and others I feel this is conservatively reasonable. I expect my torque to come in at~ 2300 and hold to 5000 or so and my peak HP to be around 5500-6000 RPM.
My oil temp stays at ~ 200° on long drives and and coolant stays below that so I'm not really worried about temps. I'm running pump gas (91 octane) without detonation and here is the build.

========================
10.3:1 CR 496
Mahle Pistons and 4340 crank , H beam rods & 7/16 rod bolts.

Ignition:
38° total mechanical advance all in at 2500RPM
- Pertronix III multi spark
- RN12YC Plugs

Intake:
- Low rise dual plane that has been port matched.

Heads:
- Brodix (2061003sscc) 115cc aluminum heads with CNC chambers (115 cc)

Exhaust:
Stainless Works CANV679 2" headers with 3.5" collectors.
Pypes - 3" stainless exhaust & mufflers

OILING:
- Moroso 7qt pan with windage tray
- Milling M77-HV oil pump
- Stewart Warner oil temp sensor
- Canton remote oil filter
- 2qt WIX 20 micron filter

Comp Cam components:
- Cam (XR294HR)
.540/.560 & 294/300 w/110 lobe separation (installed straight up).
- Short travel rollers (15854-16)
- Ultra Pro Magnum XD (1820-16)

Induction/Fuel :
- Fitech MeanStreet fuel injection
- RobbMcPerformance PowerSurge fuel supply.

Transmission:
- Tremec TKO600 (.82 5th)

Cheers and thanks for any guidance.


that sounds like it will be a fun to drive 496 BBC engine combo
you did not mention tire diam. or rear gear ratio.?

below you'll find a good base line starting point,
and Id suggest you monitor coolant and oil temps,
try hard to keep coolant temp under 200F and oil temp under 220F
verify your fuel delivery pressure is consistent over the whole rpm range
take the time to graph out and verify your ignition advance curve!
a good IR temp gun
irtemp.jpg

infrared thermometers are a very useful tool to track down issues with tuning, or mal functioning sensors , without verified facts your guessing.
this is the most consistently accurate I.R temp gun I've used for testing[/img]
42545.jpg

http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
to use on the header primary tubes helps locate fuel/air ratio inconsistency's


GENERALLY your fuel/air ratio should be in these ranges
Idle- up too about 2500 rpm try for 14.7:1-15:1 f/a ratio,
too get max mileage and prevent spark plug fouling

from about 2500 rpm- too about 4500 rpm,
try to smoothly and predictably transition the fuel/air ratio mix richer to about 13.5:1
for good power and less chance of detonation

from about 4500 rpm- too about 6500 rpm and higher
,try to smoothly and predictably transition the fuel/air ratio mix richer to about 12.5:1,
for good peak power and less chance of detonation.

this is only a well proven starting point on the tune,
but it generally gets you in the ball park ,
and tends to reduce the chances of the engine reaching detonation conditions.


the ignition advance curve needs to be checked, the chart below is a very good starting point to work from, and USE OF A RICHER FUEL/AIR MIX, WILL AT TIMES BE REQUIRED IN THE OFF IDLE TO 3500 rpm range,
btw what does a compression check show your cylinder pressure to be?
try to get the dyno test info too include your ignition advance curve and your fuel/air ratio every 500 rpm?
try to get the dyno operator to verify and show and plot out you your header collector exhaust back pressure in the collectors, and intake plenum vacuum, every 500 rpm, ?
knowing detailed info like that can be rather helpful.


but the idea here is to keep the lower rpm and lower stress operations running at efficient fuel/air ratios to reduce plug fouling and improve mileage as youll generally spend 90% of the cars operational life on the street at under 4500 rpm.

chart3e.jpg

set the plug gaps at about .045, make sure the valves are adjusted correctly

Ideal-stoichiometry.jpg


vechart.gif

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related threads

http://garage.grumpysperformance.com/index.php?threads/dyno-tune-or-not.9250/#post-51804

http://garage.grumpysperformance.com/index.php?threads/dyno-hp-loss-rates.782/#post-43454

http://garage.grumpysperformance.co...n-engine-combo-and-dyno-slip.5074/#post-14421
 
Last edited:
3:31 posi and 28"tall tires (235/55x17)
I was going to do 4.10s but the 1st gear on the TKO was lower than the previous Muncie so I don't feel I need the 4.10s any longer.
I now pull 2600RPM at ~65 and >15mpg.
 
I have always gone with the Seat-O-D-Pants dyno but for bragging rights I figure a chassis dyno will be good.
Thanks for the information.. really appreciate the wealth of info you provide.
 
glad too help were I can,
let us know how it works out.
 
The EFI unit I have is generally flexible and along with the 3 RPM break Points it also has load Break Points measured in kPa.
45 kPa is light load
75 kPa is mild load
100 kPa is full WOT
============================
Here is my new starting point although it was close to where I was. :)

RPM MAP value AFR
============================
1100 @ 45kPa : 14.5
3000@ 45kPa : 13.5
6000@ 45kPa: 13.0

1100@ 75kPa: 14.0
3000@ 75kPa: 13.5
6000@ 75kPa: 13.0

1100@ 100kPa: 13.5
3000@ 100kPa: 13.0
6000@ 100kPa: 12.5
 
The Chassis Dyno is awesome but it's best feature is first make sure you are using a brake dyno so they set different loads on the engine in order to determine Mass Brake Torque Timing which is where the minimal timing for best torque happens.
 
Well time to break out the books on that. The guy told me he advised a 0.32 gap on the plugs but this is a driver and I wonder if it is worth it to F with the plugs. They are in and only a few weeks old. Suggested NGK plugs and I run Champion... not sure I would recognize the difference.
 
Engine Builder Magazine (on the right) is a free subscription and has loads of good information between the advertisements.
The Holley book is a David Vizard product and a solid read.
 
They are both by Banish so allot of similar info might be a few new things in advanced tuning but allot of repeat info. I was able to check that one out of a local library.
 
I drove the Camaro to the Dyno yesterday and in the end drove her home with a very successful event behind me.
460HP to the wheel and a torque curve that is great. The peak torque was 470 lb/ft although from 3000 on it remained well above 400 lb/ft.Dyno_Results_Raw.jpg
 
congrats on your dyno results Please,
why not re-post the details of that engine you built's parts list,
because I know someone will ask for those details and a parts list
 
Build Details:

Block & Rotating Assembly:

- 0.60 over 454 4bolt

Eagle - B11012060 Rotating Assembly

- 4340 internally balanced crank

- 4.310in Bore x 4.250in Stroke

- Eagle H Beam Rods with 7/16" ARP 8740 rod bolts

- Mahle forged +18cc Pistons

Heads:

Brodix Race-Rite 26°2061003sscc

CNC 115cc chamber (10.2:1CR)

2.250 intake & 1.880 exhaust

Lift/Flow @28"H2O

.200/160/113

.300/224/147

.400/280/179

.500/321/203

.600/340/221

Comp Cam components:

- Cam (XR294HR) .540/.560 & 294°/300° w/110° lobe separation

- Short travel hydrolic rollers (15854-16)

- Ultra Pro Magnum XD (1820-16)

Induction:

- FiTech MeanStreet fuel injection

- GM style low profile oval (port matched)

Ignition:

- Pertronix III module (in original distributor & Rev limit set at 6300).

8° initial & 38° total all in by 2500 rpm

RN12YC plugs (gaped at .035)

Exhaust:

Stainless Works CANV679 2" headers with 3.5" collectors.

3" stainless exhaust & mufflers

Drive line:

- Tremec TKO600 (.82 5th)

- HD 11" clutch set, 650 torque capacity

- 12 bolt posi 3.31:1

- 1330 u-joints

Rear Tires:

235/55x17 - W rated (168 MPH) & 27” tall
 
that looks like it will be a rather fun to drive street/strip BBC performance combo,
that has avoided one of the major problems I see all too frequently in other engines like the all too common, 496 BBC, which many people over cam, over carb, and use too large a cylinder head on,etc.
and thats caused by failing to think through and match the drive train gearing too the cam duration , compression, fuel octane and engines intended and designed operational rpm range.
 
So you fell the combination is solid? I'm happy with it although I see articles with 10 million HP and such. I am beginning to question the numbers.
She sure is fun to drive and she may not break the tires loose at 60 but she does at 30.
 
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