Dyno tune vs. Street tune?
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From: Louisville, Ky
Dyno tune vs. Street tune?
Originally Posted by RICE ETR
Regarding the spool... i start the dyno pull at 3,000rpms because on the street i see full boost in 4th immediately when i floor it from 2800-3000rpms and my AFR goes to below 11.0:1.. but on the dyno when i floor it boost goes to 3-4psi then creeps up to max by ~4600rpms and my AFR drops as normal. I would like to see what my tq numbers would have been if the dyno would load like the street does.
Backwards on the MAF, it's all the PCM uses
above 4000RPM and steady MAP conditions.
The dyno is seldom used for part throttle
tuning and transitional throttle tuning, which
is where you spend 99+% of your time on the
street. A car that hauls *** at the track but
coughs and stumbles all the way to work (like
an automotive hangover) is no fun.
This is why you want your own tools instead
of calling the plumber for every hairball.
above 4000RPM and steady MAP conditions.
The dyno is seldom used for part throttle
tuning and transitional throttle tuning, which
is where you spend 99+% of your time on the
street. A car that hauls *** at the track but
coughs and stumbles all the way to work (like
an automotive hangover) is no fun.
This is why you want your own tools instead
of calling the plumber for every hairball.
Originally Posted by SStolen
How does this work exactly? If you are seeing full boost at 2800rpm on the street and 4600rpm on the dyno, it would seem that the tune would be way off..??
The piston speed changes with loading, and I don't mean average piston speeds. The piston speed at 4000 RPM in first gear is NOT the same as piston speed at 4000 RPM in fourth gear, even though a calculated average would show them equal.
In a high load situation like spooling at low RPM in high gear, there is a large amount of mass moving through the engine, but a relatively low piston speed. This allows boost to build and increases exhaust volume per engine revolution.
I'm not a big fan of the MAF so I won't even get into that.
On my NA cam only car, if I set my AFR on dyno to 13.1 it will richen to around 12.7 on the street. I use the dyno to only get numbers and see what it like as far as timing.
