Piper 2.5 & PCE, 21mm port, 0.9 bar, stock chip??????

[ccb056]

Just fitted the Piper 2.5 exhaust with extra silencer and PCE to our Fed Elan.
Wastegate was ported to 21mm.

Elanscan is saying the PROM ID is 5849.
Going both uphill and on level ground the turbo boosts much faster and much higher than before (0.59 bar before to 0.89 bar now).

How can I tell if this is boostcreep on a stock ecu, or if the previous owner installed an Everest chip?

Outside air temp was 0 degC.
Last year the car received new 320cc RC injectors, plugs, wires, and coils.

Elanscan data is attached.

[ccb056]

I have filtered the ecu data in excel (attached), removing periods of zero throttle, zero boost, and created some graphs for each gear.

uphill.png

1st and 2nd gear are done at partial throttle (~30%).
3rd gear is done at 100% throttle.

I am somewhat comforted by the rich AFR (12-11) while under boost.

What is interesting to me is that in 3rd gear the wastegate duty cycle peaks and is held at 35% at 0.5 bar until 0.65 bar and then drops while boost increases to 0.9 bar.

Thoughts? How would these things be different between a stock chip that's overboosting and ESM's Everest chip?
If ESM's Everest chip was fitted by the previous owner, how would I determine the revision? It looks like the latest Everest is v4.

[HJ2]

One glance at the ECU and you'll see immediately if an Everest is fitted! Look at the top of this page and go to mountain chips for pictures of how to tell...
If the boost usualy did not go this high, but was stock-ish, then most likely you are experiencing boostcreep now.
If the boost level you reach under same circumstances varies with outside temperature, then you'll know as well. (what was the air temp anyway?)

Also i don't see the boost flat out, can you drive flat out in 4th a bit longer?


For now i'd say... boostcreep

[ccb056]

I'd tend to agree the data looks like boostcreep.
I was hoping the 21mm port would eliminate the creep, I guess porting only eliminates the overboost.
The machinist that did the porting was recommending 20 mm because of clearances, he was hesitant to go the full 21.
The reason I ordered the PCE instead of the Piper downpipe was to have controllable boost at 0.65 bar.
The outside air temp was 0 degC / 32 degF.

Public roads, freezing temps, and summer tires make me hesitant to take the car out for much more testing.
When the temperatures warm up to a level more suitable for the tires I'm sure we'll be out collecting more data.
Unfortunately the warmer temperatures also decrease the air density, which decreases the propensity for boost creep.

I filtered out some data from a collection of scans I have in my Elanscan thread.
See here:
viewtopic.php?p=276698#p276698

Attached is the filtered data and some graphs.
The data was filtered to show full throttle in 3rd and 5th gear.
This dataset was considerably larger than the dataset graphed in the post above.

interstate run 0.png

As you can see in 3rd gear the boost reaches ~0.65 at ~3000 RPM and the wastegate is able to maintain that level of boost with a 35% duty cycle until 4000 RPM.
After 4000 RPM the boost climbs to ~0.9 bar with the wastegate duty cycle dropping to 0% at ~5700 RPM.
After 5700 RPM the boost begins to drop and the wastegate duty cycle stays at 0%.
We then run out of revs...

If the deadband were narrower and the wastegate duty cycle dropped to 0 quicker, I think the boost would be easier to control to 0.65 bar.

Anyone want to replace the discrete controller with a PID controller for the wastegate?

[HJ2]

As long as you don't get overboost.... Why not install an Everest chip and you're good
However, it is strange that the boost increases even the wastegate is ported to 21 mm. Does the wastegate flapper run trouble free over the full (what is it.., i guess) 100 deg?

[ccb056]

The Everest chip has been on order.

When putting the turbo back together I noticed that when the wastegate actuator rod fully extends, the flapper does not fully open.
The extent to which the flapper opens is a function of the angle between the turbine housing and the compressor housing.
I tried a few different angles, but the largest open position I could achieve with the rod attached was still less than with the rod disconnected.

See here for a similiar experience:

viewtopic.php?p=194018#p194018

This picture was taken from the other thread, but it shows about how far open my flapper goes.

tn_After porting 2.jpg

[ccb056]

Everest chip has arrived.
However, I have not installed it yet as I am wanting to get some more sample data with the OEM chip so the two can be compared while operating at similar temperatures.

Did some runs today at 5 degC/41 degF.

As usual, only graphed are full throttle conditions.

The old fuel was 93 octane (R+M)/2 with fuel stabilizer, the new fuel was 93 octane filled on an empty tank.

It looks like the intercooler is a bit undersized for boost above 0.65 bar.
MAT seems to dramatically rise causing the boost to fall.
MAT temps are hovering around 50 degC at high boost, up from around 20 degC.
Interesting to note, at 30% relative humidity air at 50 degC (1.074 kg/m3) is 90% as dense as air at 20 degC (1.197 kg/m3).... perhaps the lighter air is a significant factor in not having overboost.

old gas 1.png

old gas 2.png

old gas 3.png

old gas 4.png

old gas 5.png

new gas 2.png

new gas 3.png

new gas 4.png

new gas 5.png

[racerstev]

Be careful with the Everest chip, it will cut back on the air-fuel ratio. Add in some overboost from the exhust and
you might just run lean.

This turbo running flat out should hold 14psi at redline. More like 22 at 5000 rpm. It's good for about 220 whp at best.

Steve