[Mangler]

Here is a log with 5.5 gals of E85 and some other tweaks. I have the power delivery shifted up a good bit and it pulls all the way to 6000+.

What I cannot figure out is what is causing the load, WGDC, and boost to take a sharp dive at 5200 RPM. Is there a table or map that just reduces everything at this RPM/LOAD that is in the background that cannot be modified?

See attached log.

T

[Carl Morris]

Are you talking about the drop from about 5300rpm to about 5500rpm where you go from about 16.3psi down to about 14.7psi? I'd be curious to see what the target boost was doing there. The p-factor map doesn't clamp down much on mild overboost and it's possible you were mildly overboosting up to that point and then it came back down to the requested boost level.

[Mangler]

Originally Posted by Carl Morris

Are you talking about the drop from about 5300rpm to about 5500rpm where you go from about 16.3psi down to about 14.7psi? I'd be curious to see what the target boost was doing there. The p-factor map doesn't clamp down much on mild overboost and it's possible you were mildly overboosting up to that point and then it came back down to the requested boost level.

Yes, that is the drop I am referring to. I will log some additional parameters to see what I can find. It is doing this on all the maps I have not just this one. If you open the log in VD and graph boost, actual load, and WGDC they all have this sharp decline at 5200RPM+/-.

What about the limit map 'Requested Torque Limit (Driver)'? It peaks and starts to fall at 5200.

T

[Carl Morris]

I don't know, I set all the torque limits to 1000 and haven't thought about them since.

[Mangler]

I am starting I believe there is a resonance issue with the stock intake path at these elevated charge air flow rates. I wish I had a DCI just to do a back to back with. I'll raise the torque limits again and see what happens. My power delivery takes a dive from 5200 to 5800 then it comes back and climbs I redline.

T

[Carl Morris]

Totally depends on what your requested boost is doing there relative to your actual boost.

[Mangler]

Originally Posted by Carl Morris

Totally depends on what your requested boost is doing there relative to your actual boost.

They mirror each other exactly.

T

[Carl Morris]

OK, so if the requested boost is also dropping quickly there the question is what table or reading is causing that? This is where I've hit a brick wall with Cobb...I keep asking what controls requested boost besides requested load and I keep getting non-answer generic marketing answers. If you are very close to your requested load I'd raise it up some more and see if that changes things. It seems that everything only functions as expected when actual load stays at least 10-20 below requested load.

[Mangler]

Originally Posted by Carl Morris

OK, so if the requested boost is also dropping quickly there the question is what table or reading is causing that? This is where I've hit a brick wall with Cobb...I keep asking what controls requested boost besides requested load and I keep getting non-answer generic marketing answers. If you are very close to your requested load I'd raise it up some more and see if that changes things. It seems that everything only functions as expected when actual load stays at least 10-20 below requested load.

I'm requesting 195 but reaching 174. Something is halting boost at 5200 for sure. I will try to up the torque requested all the way across so there is no interpolation.

T

[Dethsupp0rt]

Originally Posted by Mangler

I'm requesting 195 but reaching 174. Something is halting boost at 5200 for sure. I will try to up the torque requested all the way across so there is no interpolation.

I seem to hit my loads consistently. I increased the loads on the Stage 1+ map to 190 thinking I wouldn't hit them. Found myself running 19 psi and had to back off. Now I just have to nail my timing down.

[Vwgrk1]

Originally Posted by Mangler

I'm requesting 195 but reaching 174. Something is halting boost at 5200 for sure. I will try to up the torque requested all the way across so there is no interpolation.

T

Any chance it is a boost leak? I had something similar in my prior ride and both the tuner and I thought it was an electronic issue. We event switched tuning methods, but to no avail. It was a leak at the diverter valve/intercooler connection (WRX). The turbo was working (too hard) and made its requested boost until I hit higher rpms.

[Vwgrk1]

Originally Posted by Dethsupp0rt

I seem to hit my loads consistently. I increased the loads on the Stage 1+ map to 190 thinking I wouldn't hit them. Found myself running 19 psi and had to back off. Now I just have to nail my timing down.

Shiv is saying that up to 20 psi is OK on a 50% or more ethanol mix.

[Dethsupp0rt]

Originally Posted by Vwgrk1

Shiv is saying that up to 20 psi is OK on a 50% or more ethanol mix.

OK for a couple/few dyno runs, but I wouldn't DD it without downpipes. I'm only on a 30-35% mix now anyway.

[OpenFlash]

Originally Posted by Dethsupp0rt

OK for a couple/few dyno runs, but I wouldn't DD it without downpipes. I'm only on a 30-35% mix now anyway.

With that weak of a mix, there are many things that I wouldn't do either. What you are doing with that relatively weak mix is using e85 as a octane booster. When you run straight e85 (or a reasonably strong mix), you can map for things that would be considered too aggressive for even race gas. For instance, many e85 powered drag cars dont even have/need an intercooler since e85 has near magical in-cylinder cooling properties. You just can't be stingy with it

The only bolt-on modification that you really need to support 420+whp is DCIs since the stock airbox has a very hard choke point just before 400whp.

[Willizm]

So if you guys are running a 50/50 mix are you taking into consideration that 93 octane has 10% ethanol to begin? I guess I'm asking do you guys that do 50/50 pump 6 gal of 93 and 6 gal of e85 or is it more like 6.5 gal of 93 and 5.5 gal of e85?

[Carl Morris]

Cobb made a nice table, but E85 should be about 15% gasoline, so 6 gallons of each should be close enough. It's not that critical as long as you're in the general ballpark.

[MDORPHN]

Terrific ethanol-gas mix calculator:

http://www.intercepteft.com/calc.html

Neil

[Dethsupp0rt]

Originally Posted by shiv@vishnu

With e85, you can safely run with higher exhaust back-pressure levels since it provides for much better in-cylinder cooling than gasoline. The cooling effect affords a healthy VE bump which shows itself on the dyno and the road alike. The key here is running a strong e85 mix, not a low 20-40% like many are doing.

Originally Posted by shiv@vishnu

With that weak of a mix, there are many things that I wouldn't do either. What you are doing with that relatively weak mix is using e85 as a octane booster. When you run straight e85 (or a reasonably strong mix), you can map for things that would be considered too aggressive for even race gas. For instance, many e85 powered drag cars dont even have/need an intercooler since e85 has near magical in-cylinder cooling properties. You just can't be stingy with it

The only bolt-on modification that you really need to support 420+whp is DCIs since the stock airbox has a very hard choke point just before 400whp.

Interesting. I guess I just have to worry about the long-term ramifications of running E50 then. Once in awhile couldn't hurt, right? I really liked the map I was running the other day when I was running 19+ psi testing out the FMIC.