A question about boost

[rick112]

OK so just how much boost will the 2.4 take before we send her to heaven? What will the 13lbs of boost from a stage 3 do to my little engine? Will it shorten the life and if so by how much?

[RPIpower]

Originally Posted by rick112

OK so just how much boost will the 2.4 take before we send her to heaven? What will the 13lbs of boost from a stage 3 do to my little engine? Will it shorten the life and if so by how much?

Yes, it will shorten the life as the engine was not built for boost. How much? No one knows. How much boost up the the 13psi level also depends on the the tune and what type of gas you run. I have ran into 2 people with blown motors already because of the tune.

[LANDSCAPE]

Originally Posted by RPIpower

Yes, it will shorten the life as the engine was not built for boost. How much? No one knows. How much boost up the the 13psi level also depends on the the tune and what type of gas you run. I have ran into 2 people with blown motors already because of the tune.

What tune are you referring to? And are they strictly 2.4's?

[carlintexas]

Hahn is not so big on going to 13 lbs boost with stage III. Would rather keep it down to the 12 range for use with 93 octane pump gas. If you find yourself in a 91 octane State and have to tank up - dial your GReddy boost controller down to 9-10.

Hahn says he has around 36k miles on his stage III Solstice with no failure - but I'm sure he checks the afr on a very regular basis.

I bougtht a spare motor/trans but have not had to use them yet.

[rick112]

Originally Posted by LANDSCAPE

What tune are you referring to? And are they strictly 2.4's?

Yes please more info?

[rick112]

[quote=carlintexas;226887]Hahn is not so big on going to 13 lbs boost with stage III. Would rather keep it down to the 12 range for use with 93 octane pump gas. If you find yourself in a 91 octane State and have to tank up - dial your GReddy boost controller down to 9-10.

Hahn says he has around 36k miles on his stage III Solstice with no failure - but I'm sure he checks the afr on a very regular basis.

I bougtht a spare motor/trans but have not had to use them yet.[/QUOTE

I used the example I did (stage 3 and 13psi) because I got that info. directly from the Hahn website in the area dedicated to 2.4 Sky/Solstice.

[cerberus]

Wow Rick! Got a taste of a RL and now ya want to eat them? At around 7lbs you're in RL country. Some folks say around 8's the limit before you want to start considering upgrading the top end. Don't know myself, just parroting, but 13 is a lotta punch to push through the stock driveline.

[carlintexas]

On Hahn's stage III install instructions they call for setting the GReddy boost controller at 13psi (max) with 10% safety. That brings the boost down to 11.7 psi.

I think 13 psi is possible with 100 octane or a 93/100 mix.

[RPIpower]

We already know and have been letting people know (for safety reasons) that the Hahn tune does NOT work for CA cars. We said it back in November and no one listened. Now we have two cars with blown motors asking for help. The Hahn tune (stage 2, 3, 4) require special tuning in states using 91 octane.

[Clear Bra Installer]

RPI is right. I live in vegas where 91 is the only thing available. I was offered a special tune that would allow me to run 91 but at a limit of 7 to 8 psi even on stage III. I chose to run a mix of 50/50 91 and 100 octane race gas when running about 11 to 12 psi. When I race in AutoCross, I fill up with 100 just to be safe.

Very important to pay attention to detonation, it will kill your motor quick.

Clear

[Gerry]

Have y'all considered boost-referenced water-methanol injection?

[RPIpower]

Originally Posted by Gerry

Have y'all considered boost-referenced water-methanol injection?

I've always used mater/meth injection on my turbo cars but I dont think many people want to go that route. Our goal is to make things as simple as possible. Thats not to say that it wouldnt work though.

[Gerry]

Oh, I know it would work. Just thinking of this as an option for those forced to use swill for gas and having to detune the package. It would at least give them a boost option to achieve the power they hope for.

[hdwizard]

Originally Posted by Gerry

Oh, I know it would work. Just thinking of this as an option for those forced to use swill for gas and having to detune the package. It would at least give them a boost option to achieve the power they hope for.

Speaking of swill for gas ...

Here in Phoenix we are forced to use that 10% ethanol blend crap in the winter, does that have any impact on the engine or turbo?

I know damned little about turbos, and pretty much all of that I've learned here ...

[stonebreaker]

Originally Posted by hdwizard

Speaking of swill for gas ...

Here in Phoenix we are forced to use that 10% ethanol blend crap in the winter, does that have any impact on the engine or turbo?

I know damned little about turbos, and pretty much all of that I've learned here ...

Pure ethanol has an octane rating of 105. E85 has an octane rating of 100. Downside to ethanol is your gas mileage won't be as good. If I recall correctly, gasoline air/fuel ratio is around 14.5:1. Ethanol a/f is somewhere around 9:1, giving you an a/f of about 14.0:1. In the impala, I see a 1-2 mpg drop when I'm using gasohol. But it's great for racing.

[hdwizard]

Originally Posted by stonebreaker

Pure ethanol has an octane rating of 105. E85 has an octane rating of 100. Downside to ethanol is your gas mileage won't be as good. If I recall correctly, gasoline air/fuel ratio is around 14.5:1. Ethanol a/f is somewhere around 9:1, giving you an a/f of about 14.0:1. In the impala, I see a 1-2 mpg drop when I'm using gasohol. But it's great for racing.

I just did a little more checking, and apparently they are allowed to use either ethanol or MTBE. My guess is they will go with whichever is cheaper.

So basically this will not result in performance issues, turbo problems, etc.? I'm more concerned about damage to my motor than I am about gas mileage. Any way you slice it, the Sky will drink less than my Dodge Ram ...

I've never had problems with the bike that I couldn't attribute to my own right wrist, but that doesn't mean they *couldn't* have been fuel related. Just that they were more likely related to excessive punishment ...

[carlintexas]

With the Hahn's, we've been trying to keep the a/f down to 12/1 @ wot. There may be a 'spike' to 14/1 at around 3,500 rpm when the turbo starts spooling.

[Gerry]

In the 90/10 blend (90 percent gasoline, 10 percent alcohol), ethanol is used as an oxygenate. It has a slight impact on fuel economy as well as octane. MTBE is no longer used. The 90/10 blend is harmless. E85 is something entirely different (85 percent alcohol, 15 percent gasoline) and can't be used in a vehicle, such as the Sky, not engineered for it. The primary purpose of 90/10 is to affect tail pipe pollutants. It was initially used in the boutique fuels in certain parts of the country but has spread far and wide now as a way to increase octane and supplement fuel supply.

[RPIpower]

Originally Posted by carlintexas

With the Hahn's, we've been trying to keep the a/f down to 12/1 @ wot. There may be a 'spike' to 14/1 at around 3,500 rpm when the turbo starts spooling.

Tuning WOT is farily simple. Tuning for partial throttle under boost and boost off decel is tough. The problem we have seen is the afrs are not consistant and more timing needs to be pulled for those limited to lower octane fuel. 12:1 afr is not needed when the car is not under boost. Since you have the stage 3 with the return fuel system, have you tried adjusting the fuel pressure to limit that 14:1 spike?

[carlintexas]

Eloy, not yet. I haven't had the car on the dyno since I installed stage III. I need to do so and am going to 'dial it in'. All I have done is set the boostfueler fuel pressure to the points Hahn has indicated:

55 psi pressure at idle/cruise
60 psi at 4 lbs boost
70 psi at 8 lbs boost
80 psi at 12 lbs boost
90 psi at 15 lbs boost

I did a 'simulated' boost using an air compressor rather than trying to adjust the thing 'on the road' and so I didn't have to take the car to 15 lbs boost.

The double adjustment on the boostfueler (air & pressure) were tough! I keep my test gage installed so I can check the settings from time to time.

I am considering buying a Zeitronics wide band air/fuel meter so I can monitor the afr from the cockpit.

[RPIpower]

Originally Posted by carlintexas

Eloy, not yet. I haven't had the car on the dyno since I installed stage III. I need to do so and am going to 'dial it in'. All I have done is set the boostfueler fuel pressure to the points Hahn has indicated:

55 psi pressure at idle/cruise
60 psi at 4 lbs boost
70 psi at 8 lbs boost
80 psi at 12 lbs boost
90 psi at 15 lbs boost

I did a 'simulated' boost using an air compressor rather than trying to adjust the thing 'on the road' and so I didn't have to take the car to 15 lbs boost.

The double adjustment on the boostfueler (air & pressure) were tough! I keep my test gage installed so I can check the settings from time to time.

I am considering buying a Zeitronics wide band air/fuel meter so I can monitor the afr from the cockpit.

The wideband is a good idea. We install them on EVERY turbo kit here before the customer picks up the car. That way we can datalog, etc. We just take them off if the customer doesnt want it.