Why am I hitting a power wall with my stroked RB25?

[GTSBoy]

4 minutes ago, r32-25t said:

What size is the exhaust 

On 02/10/2025 at 6:36 AM, TurboTapin said:

I have a 4" downpipe and 3.5" line with two open dumps.

 

[GTSBoy]

23 hours ago, TurboTapin said:

600-700whp isn't in the most efficient area and is close to the choke line. 800whp is well off the map.

I'm a little confused. The choke line is the far left side of the map, and you're on the right of centre. Did you mean something else? Maybe the dotted line running up the middle of the island? That's just following the peak efficiency line. It's nothing to be worried about.

[Dose Pipe Sutututu]

Post up your timing map  

[TurboTapin]

9 minutes ago, GTSBoy said:

I'm a little confused. The choke line is the far left side of the map, and you're on the right of centre. Did you mean something else? Maybe the dotted line running up the middle of the island? That's just following the peak efficiency line. It's nothing to be worried about.

You're thinking surge line. Choke line is far right line. I'm well out of the efficiency islands and somewhere around 730whp would put me past the choke line. 

[GTSBoy]

8 minutes ago, TurboTapin said:

You're thinking surge line. Choke line is far right line. I'm well out of the efficiency islands and somewhere around 730whp would put me past the choke line. 

Hahaha! You're correct. Total brain fart on my behalf. Sheesh.

[TurboTapin]

43 minutes ago, Dose Pipe Sutututu said:

Post up your timing map  

Here's my base ignition. +3 correction to redline when shooting water/meth which is always on. Looking at my old ignition table, I should be able to add 1-2 degree's next time I'm on the dyno. 

Let me know your thoughts. 

[Dose Pipe Sutututu]

Given you're running a 2.8 and my 2.5 is not really like for like, I suspect there could be a bit more timing you could give it.

What is the kW yield per degree you're putting through it?

Here's my E85 map to give you an idea, where it was I could still get another 3~4kW per degree thrown at it.

 

[TurboTapin]

21 hours ago, Dose Pipe Sutututu said:

Given you're running a 2.8 and my 2.5 is not really like for like, I suspect there could be a bit more timing you could give it.

What is the kW yield per degree you're putting through it?

Here's my E85 map to give you an idea, where it was I could still get another 3~4kW per degree thrown at it.

 

Thanks for this! I can't recall the exact power per degree, I was focused on getting the new meth system going. I'll get back to you after I get back on the dyno. Cheers. 

[GTSBoy]

What's the static CR with the capacity bump?

[Butters]

Sorry, can I confirm what fuel you are using ? 

 

As I read it, I assume its 98 octane with methanol injection on top(with water?) ? or are we talking straight methanol ? 

If you are on 98 octane those power numbers are pretty close to what you would expect for a 6466.  You will get another 100kw with E85. 

[GTSBoy]

2 minutes ago, Butters said:

If you are on 98 octane those power numbers are pretty close to what you would expect for a 6466.  You will get another 100kw with E85.

Which he should also be able to get most, of not all of, with WMI.

Whereas WMI is not the thing you would expect to see effort put into on top of E85.

[Butters]

zero expert on WMI, just never seen anyone actually make power with it. More used to keep an engine alive when being pushed on knock limited fuels.  In lots of examples, if not setup correctly people go backwards with WMI.  

again no personal experience with this, just what I have seen from the side of a dyno booth

[Murray_Calavera]

36 minutes ago, Butters said:

More used to keep an engine alive when being pushed on knock limited fuels. 

This is where the power comes from, more timing. more power.

[Predator1]

Please tell me its not a Artec manifold.................. 

[TurboTapin]

On 03/10/2025 at 9:06 PM, GTSBoy said:

What's the static CR with the capacity bump?

9:1.

[TurboTapin]

On 04/10/2025 at 8:54 PM, Butters said:

Sorry, can I confirm what fuel you are using ? 

 

As I read it, I assume its 98 octane with methanol injection on top(with water?) ? or are we talking straight methanol ? 

If you are on 98 octane those power numbers are pretty close to what you would expect for a 6466.  You will get another 100kw with E85. 

 

On 04/10/2025 at 9:07 PM, Butters said:

zero expert on WMI, just never seen anyone actually make power with it. More used to keep an engine alive when being pushed on knock limited fuels.  In lots of examples, if not setup correctly people go backwards with WMI.  

again no personal experience with this, just what I have seen from the side of a dyno booth

94AKI so I believe it's roughly 100-101ron. We don't have E85 at the pump in Canada, so it's either race gas or water methanol injection. I run a 50/50 mix. Since 4$ a liter race gas is expensive, WMI is often used here. I'm currently running a constant pressure system with direct port nozzles. We tend to see roughly the same from WMI as we do on E85 race gas. Fueling is not my issue. 

Have you seen anyone run more than say 520kw(~700WHP) on a mainline limited at 7600RPM on a 6466? This is the sort of comparison I'm looking for. If I could rev it up to 8500-9000rpm, I believe I would be seeing the HP I was originally expecting. Thanks. 

[TurboTapin]

6 hours ago, Predator1 said:

Please tell me its not a Artec manifold.................. 

It's a 6boost, T4 twin scroll, twin gate. Have issues been popping up with the Artec's? 

Edited 9 hours ago by TurboTapin