My 20v 2.5 stroker track day ur quattro

[prj]

Something definitely still wrong.
500hp is not that hard on 8.0:1 CR on this turbo.

Also, these turbos (GT3076R/GTX3071R) keep making more and more power all the way until they run out... There is no way you are hitting octane limit if your CR is what it is.

I usually run GT3076R's 32-33 taper 30 on 2.2T's. On a 2.5L it should still be able to push at least 30 taper 28.

As for detonation - of course you are going to get detonation at some point if you keep advancing timing, but on 8.0:1 you can easily run 15...22 timing up top if not more.

This is assuming 0.82 hotside of course. If it runs 0.63 on a stroker the results are not surprising in the least.

[AndyP]

What were you using to listern for det?

[A80Avant]

But my 3076 was on the. 63 ar and still made power up to 6200rpm before EGTs becoming a problem..so perhaps on a stroker is a bit worse as more gasses are coming out.

[prj]

Correct, on stroker it's gonna be much worse, and its going to choke the engine hard.
0.63 A/R is a very poor choice for a stroker.

If it still has a 0.63 A/R on it, then that explains why it just started to knock, as the backpressure in the EM went sky-high.

[DamoM]

That's possibly the first GTX3071 measurement on the i5 engine even 2.5l

Not bad I have to say for 25psi. Why is the car detonating? What is the compression ratio?

These turbos are able to produce quite a lot with more boost so long as there is no detonation as their map is wide.

The plain 3076R on mine T 1.8bar tapered to 1.7 had done something very similar. The whp was 367 on dyno dynamics and their flywheel derivative was 464hp crank

Yeah the crank figure is such a stab in th dark and varies so much that I'd much rather rely on whp

[DamoM]

7.6:1 ? is that your measurement or what JE spec sheet said?
As they seem to have a habit of ****ing up the calcs on CRs for these strokers

It was theirs but we checked it and it was bang on.

[DamoM]

Something definitely still wrong.
500hp is not that hard on 8.0:1 CR on this turbo.

Also, these turbos (GT3076R/GTX3071R) keep making more and more power all the way until they run out... There is no way you are hitting octane limit if your CR is what it is.

I usually run GT3076R's 32-33 taper 30 on 2.2T's. On a 2.5L it should still be able to push at least 30 taper 28.

As for detonation - of course you are going to get detonation at some point if you keep advancing timing, but on 8.0:1 you can easily run 15...22 timing up top if not more.

This is assuming 0.82 hotside of course. If it runs 0.63 on a stroker the results are not surprising in the least.

Hey Dmitri. It's running 0.82. I'll find out what timing we were running.

[prj]

If it's running 0.82 you should be able to get 500 crank.

[DamoM]

What were you using to listern for det?

I believe it was cans. This engine is very noisy though. The ecu knock management calibration kept confusing engine noise with det til the frequencies were adjusted.

[DamoM]

If it's running 0.82 you should be able to get 500 crank.

Ok I'll let you know the timing figures.

[DamoM]

If it's running 0.82 you should be able to get 500 crank.

The dyno operator was using their equipment for det. The car was sill gaining power with added timing but it was a diminishing return but the guy mapping naturally wanted to avoid detonation. It made almost as much power at 25psi as 30psi and the gain in power wasn't worth running the extra boost (pressure, heat etc).

It was running 19 deg timing when he tried 30 psi.

A bit more fuel was added to prevent detonation which dropped the power slightly as it's running quite rich on full boost.

Obviously the characteristics of a stroker are different to the 2.2 as piston speed will be higher and therefore so would the timing.

Have you ever mapped a stroker?

Do you have any dyno plots of I5s with this turbo (either 2.2 or 2.5) for comparison?

[prj]

The dyno operator was using their equipment for det. The car was sill gaining power with added timing but it was a diminishing return but the guy mapping naturally wanted to avoid detonation. It made almost as much power at 25psi as 30psi and the gain in power wasn't worth running the extra boost (pressure, heat etc).

It was running 19 deg timing when he tried 30 psi.

A bit more fuel was added to prevent detonation which dropped the power slightly as it's running quite rich on full boost.

Obviously the characteristics of a stroker are different to the 2.2 as piston speed will be higher and therefore so would the timing.

Have you ever mapped a stroker?

Do you have any dyno plots of I5s with this turbo (either 2.2 or 2.5) for comparison?

Need a full log of the pull to say anything. Now everything is just very vague.
The most recent stroker that I mapped is this one, IIRC 560whp:

http://prj-tuning.com/?p=370

Sounds to me like you didn't run nearly enough boost to be honest.

[DamoM]

Need a full log of the pull to say anything. Now everything is just very vague.
The most recent stroker that I mapped is this one, IIRC 560whp:

http://prj-tuning.com/?p=370

Sounds to me like you didn't run nearly enough boost to be honest.

That is a tool!

But what about the det? One run at 30psi with det is going to ruin the engine isn't it?

[prj]

That is a tool!

But what about the det? One run at 30psi with det is going to ruin the engine isn't it?

Not if you adjust timing correctly.
You can melt your engine at 25 psi if you over-advance the timing. Hell, you can melt a bone stock AAN at 1 bar if you over advance the timing.

On a 7.6:1 CR motor, I'd be running that turbo with the wastegate shut almost the entire time... but that's just me.

If you want to understand this better, pick up one of Greg Banish' books on the subject, or maybe even something from A. Graham Bell.
They'll both do a much better job explaining these things than I ever could.

[DamoM]

Not if you adjust timing correctly.
You can melt your engine at 25 psi if you over-advance the timing. Hell, you can melt a bone stock AAN at 1 bar if you over advance the timing.

On a 7.6:1 CR motor, I'd be running that turbo with the wastegate shut almost the entire time... but that's just me.

If you want to understand this better, pick up one of Greg Banish' books on the subject, or maybe even something from A. Graham Bell.
They'll both do a much better job explaining these things than I ever could.

Ok and please excuse my ignorance but what is the point of adding more boost, getting detonation, having to retard the ignition to compensate which results in you gaining virtually no more power? Surely you are better off leaving the boost at the level it was at in the first place?