It is system dependant , it all boils down to how much filtering your Lambda system is setup for . This filtering value along with exhaust speed and temp will alter the A/F , you will find the A/F will be more stable after you have brought everything up to temperature, On the Dyno jet what you should have done was an all gear pass, this would have brought up your egt's and you would see a more accurate A/F value thru 3/4/5 gears.

 

Neither am I just some techno banter , while i help another racer . Just figure i had to explain my position..... as i use/have used almost everytype of
dyno made, while the dynojet has it's weakness, it has positives like all dynos' it requres a different procedure to go , but it will go, of all the dynos i have used over the years i have only encountered 2 that was totally useless , but unless you happen to be in Italy , this should not be a worry ...

Forget the streets go back to the Dyno jet and do an all gear pull to 4th , then stop check your A/F adjust accordingly , then make an all gear pull to 5th when you have the A/F where you need them . remember to watch temps , keep the I/C temps stable , so the runs are comparable..

 

I wish I had 5 gears...

 

then 1/2/3 is sufficient .....4 after all is good... but not reverse

 

Wayne, I'm not trying to start a war here, I have and do use steady state tuning for all engines I tune and I have done several non Porsche engines that make over 320kPa (32psi of boost). I dial the dyno to 5000rpm and set the boost controller to run 32psi of boost and will steady state the engine to find the optimum ignition angle. Want me to call you the next time I do it?

 

NO war here geoffrey , just giving my opinion for mutual exchange

Would love to see the steady state tune at 5250, 32 psi on a Dyno dynamics. we should get together .. you can use mine if you want.

 

With the exception of in-cylinder pressure analysis equipment, I honestly don't know how to find the optimum ignition angle any other way.

 

Not dis-agreeing with you on that point geoffrey , just pointing out there are many ways to skin a cat, there are always limitations to work with and on the high side will require all and more of what you have mentioned. My Dyno Dynamics is available to you anytime , we can get together as techniques required for steady state tuning is diametrical to dynamic tuning, we can get together over this ..

 

Well, I just scheduled some more dyno time on Friday with a shop that has a DynaPack. 1 hr away though...

We'll see what they show... This is the same dyno I tuned it on a while back...

Brian

 

I'll meet you there at about 4:30pm if you still there at that time

 

Brian,

This might sound stupid but I put my car on a dynojet once and the operator put a fan blowing from the back (into the exhaust pipes). My AFRs were in the 14-16s during the run, which is obviously incorrect as I run rather rich. I did not have any other explanation than it was the fans that were fooling the numbers as a result of the amount of air thrown at the sensors.

As I said, it sounds impossible maybe , but true.

 

I could definitely see where that could throw off the AFR reading... Doesn't apply to my particular situation, but interesting to consider for future dyno runs for sure!

thanks Jean!

Brian

 

Well, went back to the dyno today. Spent about 2.5 hrs making adjustments.

Ended up with 447.8RWHP at .87 bar... (somewhere between .85 and .90, I'll have to look at datalogs). Most of the changes centered around timing, which obviously forced changes to fuel as well.

ALSO, had the wonderful pleasure of meeting Olli today. Olli, I hope next time, we'll see one another at a venue where we can actually talk, and things aren't so hectic...

Anyway, 2 weeks from now I'll be at the track!

Brian


This was my 3rd time on a DynaPack, and every time I leave, I wish I had the money to buy one....

 

Brian,

Did you get the increase you were looking for?

 

Thanks Brian, the pleasure was completely on my side. Your car is truly awesome
Looking forward to meeting you again, and hopefully other Rennlisters like A930Rocket on May 26 at VIR