ehall

laust is running water injection.

ehall

special tool ONLY does that on a VERY serious race gas mixture

clouddomino

Gotcha, so pretty much the max streetable psi for our cars is 18-21psi?

rberry951

There's more to consider than just detonation. Yes, a good chip tuner can map a chip that will be safe from detonation at those boost levels, but you're going to have other issues to deal with. Valve float, head lift, exhaust induced backpressures, etc. So to 'safely' run greater than 18psi all the time you need head work, you need a head gasket and studs/bolts designed to handle it, and you'll need to upgrade your injectors if you haven't already or you will over tax them.

Regards,
Russell

DDP

Depending on timing. Back in the day when Danno would burn the 18psi chips he retarded the timing quite a bit.

ehall

Personally I wouldn't go past 18. As I always say though, there are a ton of ways to skin this particular cat. To me, the bst way is to match everything from the ground up for the specific goals of the car/engine. The bottom line to me is that chips alone won't do it.

special tool

I sure have never run 28 on pump gas!
I have run 30+ psi with a smaller compressor.

It doesn't really do anyone any good to limit the talk to PSI, because my turbo makes 400 RWHP at 18 PSI. A k26 doesn't do that.
We need to talk about combustion pressure-related headgasket failure/head lift/barrel movement - these things show themselves at 550 FT/LBS torque with good tune on a 2.5 liter 8 valve 951.

2bridges

Clouddomino - I am not sure how you arive at your safe boost level on pump gas.

I for one would not consider over 18psi on straight pump gas..... and even them a little nervous. Your car and you are entitled to blow it up if you like.... running 18-21 on pump gas will certainly do that for you

Rogue_Ant

I disagree. A more efficient compressor will produce a cooler intake charge at x psi. Thus warding off detonation. Also, the more free-flowing the turbine side, the less reversion and backpressure. Which will also help to raise the detonation threshold.



Rogue

DDP

If you're set on those boost levels on pump gas, run water injection.

clouddomino

Just was trying to feel out what everyone thought about it. I'd like to run 18+ psi but if that's going to majorly effect daily drivability then I'll have to reconsider. I know a few people with so japanese imports running 25+ psi on pump gas without a ton of mods, what makes our cars inable to do this?

ehall

I wrote that unclearly. It should have read that detonation isn't going to change based strictly on the turbo. My point was that there are many factors that go into detonation, and just changing the turbo is a long way from eliminating all of the additional factors.

DDP

The crappy head design

DDP

...open deck...

2bridges

"japanese imports running 25+ psi on pump gas without a ton of mods, what makes our cars inable to do this?"

I believe somebody is misleading you. 25psi on pump gas is absurd. Maybe a one time shot... and it was probably 20 and grew to 25 the more they told the story. Is BS