(TURBO) What makes/supports 500-550HP reliably for our cars?

[CSG Mike]

Originally Posted by dholloway543

Are you running E85 only or 91 also. The reason im stuck at 8-10 is because i enjoy my flex fuel and dont want a dedicated e85 car. If you are chasing those numbers over dailyability then e85 can yield higher boosts

I'm also flex, have ~56k miles on the car, 120+ track events, and a handful of championships and records. I'm definitely taking sustainability over numbers.

I'm still on my original engine; the 12.5:1 compression I mention is stock in my case. In fact, the engine itself is still 100% stock and OEM.

[dholloway543]

Originally Posted by CSG Mike

I'm also flex, have ~56k miles on the car, 120+ track events, and a handful of championships and records. I'm definitely taking sustainability over numbers.

I'm still on my original engine; the 12.5:1 compression I mention is stock in my case. In fact, the engine itself is still 100% stock and OEM.

Can I ask what boost your running, and is your cam Maps the OFT set or the TommBRZ cam Maps

[CSG Mike]

Originally Posted by dholloway543

Can I ask what boost your running, and is your cam Maps the OFT set or the TommBRZ cam Maps

I run up to 12.5, and my cam tables are bespoke to my car, tuned by Zach Tucker. Zero corners cut with my setup and tune.

[DarkPira7e]

Originally Posted by CSG Mike

I run 12.5:1 with a boost level that is in the "red" on your table. Knock is definitely not an issue... you may want to investigate why you're knocking at just 10 psi.

I want to second this. I ran 17PSI on 12.5:1 with no knock with a T3 60 trim Garrett turbo. No knock. Ecutek Racerom, custom dyno tuned
This is on 93 octane.

[solidsnake11]

Originally Posted by CSG Mike

I run up to 12.5, and my cam tables are bespoke to my car, tuned by Zach Tucker. Zero corners cut with my setup and tune.

Your making 500-550?
I also remember you saying you also slowed your spool down?.

So just limit your boost to 7 lbs until 7000rpm then up it to 20lbs, then you have a reliable 500.

[CSG Mike]

Originally Posted by solidsnake11

Your making 500-550?
I also remember you saying you also slowed your spool down?.

So just limit your boost to 7 lbs until 7000rpm then up it to 20lbs, then you have a reliable 500.

I don't make anywhere near 500-550, which is why psi is a terrible measurement of power

Spool is not slowed down. Rather, I have rising rate boost.

[Irace86.2.0]

Originally Posted by dholloway543

Im not sure why but more boost = more power even though the overall cp is the same. My guess is that its less of a fighting force as the piston comes up so less power is waited on the compression stroke. More power in boost less power out of boost.

I've heard it said different ways, and all ways of saying it probably contribute:

--Increasing pressure increases heat a lot, and it is in a non-linear way, so higher compression can lead to knock, which limits boost potential or makes it necessary to reduce timing a lot.

--I have heard that high compression/low boost means there is less manifold pressure wanting to inject air into a cylinder that is a smaller space versus low compression/high boost where there is a lot of manifold pressure which pushes a lot of air into a bigger cylinder.

[Irace86.2.0]

Originally Posted by DarkPira7e

I want to second this. I ran 17PSI on 12.5:1 with no knock with a T3 60 trim Garrett turbo. No knock. Ecutek Racerom, custom dyno tuned
This is on 93 octane.

That seems aggressive. My Harrop kit is hitting around 12-12.5psi, and Zach Tucker wasn't too happy with me running 91; he thought it was too much boost for 91. I have E85 now. The car is happier.

[Irace86.2.0]

Originally Posted by CSG Mike

I'm also flex, have ~56k miles on the car, 120+ track events, and a handful of championships and records. I'm definitely taking sustainability over numbers.

I'm still on my original engine; the 12.5:1 compression I mention is stock in my case. In fact, the engine itself is still 100% stock and OEM.

I remember reading that your engine was rebuilt to CSG specs, but with OEM components.

[86TOYO2k17]

Originally Posted by Irace86.2.0

That seems aggressive. My Harrop kit is hitting around 12-12.5psi, and Zach Tucker wasn't too happy with me running 91; he thought it was too much boost for 91. I have E85 now. The car is happier.

As long as you have timing that can be removed you should theoretically be able to continue to increase boost. But at a certain point you reach the “threshold” of that octanes ability and increasing boost will require you to pull so much timing that you will not gain any more power and potentially lose power but with all the inherent increased risk of more boost, so it’s essentially pointless to go beyond a certain boost with certain fuels.

On 12.5-13psi on my failsafe 92 map i still have a decent amount of timing although I’m probably right at that limit where more boost is pointless maybe even already a little beyond the limit, i would need to dyno comparison to know for sure. With my WMI i probably have a little bit more headroom left as i can safely run a bit more timing and obviously cooler IAT helps a lot too.

[Irace86.2.0]

Originally Posted by solidsnake11

https://mechanicbase.com/engine/turb...rbo_spool_time


Ok?

I think what he said was confusing too. “A rising rate...”?

I think what he is trying to say is that his torque curve/boost rises across the rpms like a JRSC. If he is tracking it a lot and staying high in the rpms then such a setup would not hinder performance, but the benefit would be better reliability around town. Too much torque down low seems to be a recipe for rod failure. This with a lower boost level in low gears seems best.

[Irace86.2.0]

Originally Posted by 86TOYO2k17

As long as you have timing that can be removed you should theoretically be able to continue to increase boost. But at a certain point you reach the “threshold” of that octanes ability and increasing boost will require you to pull so much timing that you will not gain any more power and potentially lose power but with all the inherent increased risk of more boost, so it’s essentially pointless to go beyond a certain boost with certain fuels.

On 12.5-13psi on my failsafe 92 map i still have a decent amount of timing although I’m probably right at that limit where more boost is pointless maybe even already a little beyond the limit, i would need to dyno comparison to know for sure. With my WMI i probably have a little bit more headroom left as i can safely run a bit more timing and obviously cooler IAT helps a lot too.

If you max out timing in ideal conditions then won’t it be risky in less than ideal conditions like on a track or on a hot day because then the engine has no wiggle room to adjust timing?

[86TOYO2k17]

Originally Posted by Irace86.2.0

If you max out timing in ideal conditions then won’t it be risky in less than ideal conditions like on a track or on a hot day because then the engine has no wiggle room to adjust timing?

I over simplified it, and I'm assuming by “max out” you mean no timing left to pull? If so then, Yes sort of.

As boost increases heat exponentially increases once it hits the tipping point of the octanes abilities you start pulling exponentially more timing, and like I mentioned the inherent risks of running more boost increase, so it’s recommended to not just throw all the boost at it even if you technically “could”.

Hypothetically, Say going from 8 to 10psi you drop from 19 degrees timing to 17 degrees timing. Say 1 psi is 4% whp, 1 degree of timing is 2% whp so you still have a net gain of 4%, but say the “threshold” of 91 is at 10psi, meaning going from 10-12psi your timing to not have knock goes from 17 to 13 degrees. 8% gain from boost but 8% loss from timing so You gained no power, but now have the added risks and increased temps of more boost for no benefit. Then you go 12-14psi but timing goes from 13 degrees to 5 degrees. And now you just lost power. As you see because the heat increase is exponential so is the timing being pulled to accommodate. This is why it’s technically possible to run say 14psi with 91 but highly not recommended, and running 10psi would be ideal as you make max power still, but still have some safety wiggle room for error/increased temps from driving hard, at 12psi you still make peak power but with basically no wiggle room. And at 14 psi you might actually lose power and have zero wiggle room.

So the ideal “threshold” of the octane is when you can still make max power but at the lowest boost level for highest margin of error. And if you drive hard like tracking that threshold decreases because your temps will obviously be a lot higher.

[CSG Mike]

Originally Posted by Irace86.2.0

I remember reading that your engine was rebuilt to CSG specs, but with OEM components.

That's CSG's car, not mine. That was just all OEM components, but balanced.