flat land turbo/pump gas

[aja636]

Hello guys, I am building a 2018 switchback assault with a modified boondocks turbo
30/76, external waste gate, added injectors, and Meth spray to control intake temps.
I also have a Indy Dan warthog motor I am installing to go with this whole set up.
144 track for lake racing and trail riding.

My plan is to stay 91 octane for 95% of the time, with the occasional race day where I will take her as far as I can. 15-18-20psi on straight 116 or 120 octane.

Just looking for any advise that might help this build on timing, compression, or anything else to add in.

Thanks

 

[xpturbo600]

Hello guys, I am building a 2018 switchback assault with a modified boondocks turbo
30/76, external waste gate, added injectors, and Meth spray to control intake temps.
I also have a Indy Dan warthog motor I am installing to go with this whole set up.
144 track for lake racing and trail riding.

My plan is to stay 91 octane for 95% of the time, with the occasional race day where I will take her as far as I can. 15-18-20psi on straight 116 or 120 octane.

Just looking for any advise that might help this build on timing, compression, or anything else to add in.

Thanks

If you are going that high, you need to be careful.

1. It will break reed petals.

2. Most people stay under 14 because the polaris motor starts to choke flow because of runner design limits much after 14 with a large turbine and housing.

3. A person I know who ran a similar setup with a vipec standalone kept blowing the pipe off at high boost because the factory polaris pipe just won't flow enough with a big turbo. In his case, more boost did not translate to more power. Mass flow requires a pressure differential between two points. Under high boost, his back pressure increased with boost, so the differential did not increase. Instead, more boost translated into increases in charge pressure and intake temps with no power gain.

In short, the polaris motor starts to really lose efficiency at the boost levels your are talking about. Not to mention you will probably be fixing it as much as you ride it.

 

[aja636]

Great feedback. Thanks. My main plan is 8-10psi on pump. And maybe see where it can go on race day. There’s another guy in NY where I run that has basically the same set up. He’s been up to 20psi and mainly stays in the 14-15psi area. At 1500’ elevation the sled is a handful at 15lbs.

 

[Sheetmetalfab]

Great feedback. Thanks. My main plan is 8-10psi on pump. And maybe see where it can go on race day. There’s another guy in NY where I run that has basically the same set up. He’s been up to 20psi and mainly stays in the 14-15psi area. At 1500’ elevation the sled is a handful at 15lbs.

You must have some nice pump gas.

Or are you talking “avgas pump”?

 

[aja636]

You must have some nice pump gas.

Or are you talking “avgas pump”?

no. just 91 non ethanol. where I ride all the places go through fuel quickly. little chance of stale old fuel

 

[Sheetmetalfab]

Hopefully that 91 octane and 10 psi works out for ya.

 

[xpturbo600]

You will want 100 octane to run 10 psi. Straight pump at 10 psi without reducing compression below factory will probably detonate. Or, you could lower the timing with a standalone if you plan to run one.

 

[nytro41]

You will want 100 octane to run 10 psi. Straight pump at 10 psi without reducing compression below factory will probably detonate. Or, you could lower the timing with a standalone if you plan to run one.

I think you can adjust the timing down with the elevate box. standalones are expensive.

 

[aja636]

Hopefully that 91 octane and 10 psi works out for ya.

that's why I am adding the methanol spray.
Im going for stock compression motor and stock timing to start.
Going to use the Torque link to make changes in ECU for timing etc when we get the sled up and running.
Having the ability to make changes in the factory ECU, a stand alone eco isn't needed.
I know a couple guys that have run 12-14lbs boost on pump and meth on 100% stock motors.