After knowing Daryl for a couple years (bought his old exhaust), I finally got a ride in his car a couple weekends back, as well as a bit of driver's seat time.

All I can say is wow. Once I pay off the S and can pick up a daily driver, all my pennies will be saved for one of these kits!

 

Ahhhh.....so you were impressed! LOL

 

Yeah, you could say that!

It was very much with those tires! hahaha

 

What's the most psi you guys would recommend running on the gtx3076r on 91 octane on stock block?

 

Recommend only 12-13psi max on 91 octane.

Drew. R

 

Thank you. So weird how the shop that tuned my car recommended 16psi, yet nobody else does lol.

 

Ya most people wouldnt say 16 psi on 93 oct...

 

What's the story on psi limits and octane 91/92/93 ?
Can I assume the way to overcome is e85 or meth inj ? If yes, what's the limitations on psi with those ?
Gracias for the knowledge !

 

The limitation is detonation. An increased in cylinder pressure (boost) will increase the chance of detonation. http://www.enginelogics.com/detonation.html



Here's a series of log at 15psi on 91octane, Ptuning GTX3076R. Notice the difference in ignition timing vs. knock. Knock = detonation.

The goal is to achieve optimal ignition timing with no detonation at a given boost pressure.

The last graph is at 13psi with ignition timing of 12.


Most tuners will tune to the safest ignition advance and boost.

Currently I'm at 16-17psi on 91oct... based on many hours of street tuning and risk taking....

Retarding the ignition advance to run a set target boost will increase exhaust temps..to the point of melting valves...that's another limitation in itself.

 

The limitation is detonation. An increased in cylinder pressure (boost) will increase the chance of detonation. http://www.enginelogics.com/detonation.html



Here's a series of log at 15psi on 91octane, Ptuning GTX3076R. Notice the difference in ignition timing vs. knock. Knock = detonation.

The goal is to achieve optimal ignition timing with no detonation at a given boost pressure.

The last graph is at 13psi with ignition timing of 12.


Most tuners will tune to the safest ignition advance and boost.

Currently I'm at 16-17psi on 91oct... based on many hours of street tuning and risk taking....

Retarding the ignition advance to run a set target boost will increase exhaust temps..to the point of melting valves...that's another limitation in itself.



[/quote]

Thanks, great explanation assuming it's correct as I'm no expert, just looking for insight as to what's going on.
* I asked a some other questions that I'll repeat as maybe you didn't see..
Can I assume the way to overcome (the octane/detonation issue) is e85 or meth inj ? If yes, what's the limitations on psi with those ?
* New question - Why does the alcohol overcome the octane and detonation problem ? Does it detonate at a higher temp and/or pressure than gas ?
Thanks !