Dyno tuning WOT

[ringram]

Given my understanding that holding max rpm and WOT for too long isnt good for the engine. Does anyone have any tips for dialing in spark on the dyno?
Or should I be fine holding like 6000rpm at 100% TPS and like 0.90g/cyl load for 30secs?

What about dialing in the whole RPM band from say 1200 to 6400 along the same load cells?, Then all the other load cells?

Should I take it in stages of no more than say 4 min at a time etc.

Advice appreciated... Im not planning on a new yet.

[Delco]

Given my understanding that holding max rpm and WOT for too long isnt good for the engine. Does anyone have any tips for dialing in spark on the dyno?
Or should I be fine holding like 6000rpm at 100% TPS and like 0.90g/cyl load for 30secs?

What about dialing in the whole RPM band from say 1200 to 6400 along the same load cells?, Then all the other load cells?

Should I take it in stages of no more than say 4 min at a time etc.

Advice appreciated... Im not planning on a new yet.

Nothing wrong with holding a engine at load for a period as long as the cooling system and airflow over the engine are sufficient.

We use to do testing where the engine was held at max power for 20 hrs straight then at no load same rpm for 20 hrs , then go onto the next rpm band and repeat . After that I had no problems with holding steady state for hrs on end mapping each load point for emmisions and power as well as economy then blending all three to get the best comprimise.

To do any proper mapping you need to get the engine to the load point and let it stabilise , then start playing with timing and fuel to get the best balance - this is the only way to find MBT as it cant be done on the road.

[Redline Motorsports]

Prior to the Road Runner system, we used to tune GEN7's & FAST dfi units by setting the dyno by rpm to hold load. For example, we would set the dyno load to 3200 rpms. I would hold the throttle at a given KPA (or in this case MAF load gms/cyl) and start adding timing from a already low starting point. I would then observe the torque reading and find the point to which no more increases take place. At this point we have reached peak cylinder pressure. I then back down a couple degrees, and more throttle input and move to the next load point along the 3200 rpm range. While this is happening you need to monitor the temps.

Very much like VE tuning, there are cells you just aren't going to hit. Some of which is that you just dont see that condition or you are so deep into heavy loads that you need to start out light and tune for KR limits under load.

Now thanks to RR we can do the same. Unfortunately I haven't had a chance to try it yet the methodology is the same.

Boost motors are a bit tougher due to heat that is built under load. Timing that works well at 180 degree coolant temps is not the same as 225! I will usually start at 2000 and go to 3000 and let it cool. Then 3000-4000 etc....

This is done on a Dyno Dynamics dyno!

Howard

[Delco]

If we have a really serious engine i normally hook the cooling sysetm up to a outside source so I can maintain a constant coolant temp with no issues , lots of fan over motor and exhaust and then it isnt a issue.

[ringram]

Thanks for the info all,

Lucky its like 5 deg C here at the mo, so the ECT temps were 80-86*C (due to fans and 160* thermo) so temp wasnt a problem, rear tyres did however start to melt. Ill suggest to the dude to blow a spare fan onto them.

Dan, while looking at emissions, power and economy was this mainly an AFR thing? Or did you mess timing around too? Or just choose AFR based on the above requirements then set timing to MBT to suit?

Sounds like an extended mission. I guess it depends on how far I want to go.

My plan was 14.8:1 up to around 80kpa then progressively richen to around 12.8-13.1:1 at max kpa (90-100) (13:1 at low and high RPM and 12.8 around peak torque) Is that a fair plan or should I mess with AFR across the range too?

Is there any general rules?

[Delco]

Thanks for the info all,


Dan, while looking at emissions, power and economy was this mainly an AFR thing? Or did you mess timing around too? Or just choose AFR based on the above requirements then set timing to MBT to suit?

?

Fuel AFR , Fuel timing , ignition timing as well as getting the offset tables right

For a street car getting the AFR close then chasing MBT is the best plan of attack.