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Previous Next Up Topic Engines / Subbug - Subaru Power / Turbos and Octane (13800 hits)
By Don L 1157 Date 2008-11-27 00:26
Hi All,

I've been looking at the OutFront website, and cannot but notice the connection between turbo boost, higher octane, and horsepower. 

Assuming you have a driver adjustable waste-gate to control the boost of the engine, can you drive on a lower octane fuel??

You know that having 300-400hp under your lead-foot would be exquisite now and again, but being able to put pump gas into your car on a daily basis might be a tad more desireable.  So, if you have the 300 hp engine, and turn the boost down to 5 pound, can you run 91 octane.  Blending in an octane booster to accomodate you 15 pounds of boost could be a programmers nightmare!!

Comments....observations....experiences.....these days we seldom re-invent the wheel if we look long enough.
Don in the Mountains of West Virginia
By Mel Adjusted Date 2008-11-27 02:46 Edited 2008-12-01 08:53
When turbo'ed, supercharging or liquid supercharging a engine there's many thing you can do to prevent denotation at hi power settings. It's so sweet to have lots of power at your finger tip and with alittle planning you can make it work like a dream.

When a engine is built with good rods,pistons and head gaskets it's a shame to let all that potential go to waist when all you need to do raise the boost or add a good shot of spray... I'm talking about 15# lbs and more of boost.

High octane fuel is the way to go but racing gas is expensive and for everyday driving not possible unless you own a bank... What the makers of racing gas don't tell you is what it's made of. With out going into a lot of writing it's easier to lead you to a link that will explain it all....   http://www.elektro.com/~audi/audi/toluene.html

Next were looking at cooling the intake are temp.. This can be done with a intercooler and/or water/alcohol injection. I use the w/a injection method as I hook it into a pressure switch so when I get to a certian boost it starts the cooling affect. The cooler you can get the inlet air temp the more boost you can run.

You can retard the timing but I never liked doing that cause the more you retard the timing the less power you make... so your kinda defeating the purpose you trying to achive.. I don't like this method and would rather run my mixture a little fatter, meaning run the fuel/air mixture a tad bit richer.

I can hear some of you wondering if I've lost my mind... What the hell is liquid supercharging?
Well lets look at supercharging. Spercharging is nothing more than adding more oxygen bearing air to the engine making it think its a bigger engine... What? OK, I'll explain... You have a Normal Asperated (N/A) which is 2.0L which has 100 HP at sea level.... if you boost the intake pressure to 14.7 lbs youve just doubled the amount of oxygen to the engine and if you add the right amount of gasoline to this added air your engine will think it's a 4.0L engine... Now if you really want to get into the twilight zone run the boost up to 29.4 lbs and make the engine think its a 8.0L engine.. Now your talking some serious power.. and with proper planning east to do.... but what the hell do this have to do with liquid supercharging? During WW2 the Germans ran liquid supercharging on there ME-109 figher's and with a flip of a switch induced more oxygen and fuel into the engine and would outrun our planes in a heart beat.

http://www.nitrouskits.co.uk/history.htm
http://www.idavette.net/hib/nitrous.htm

Myself in one of my cars I run a 75 HP shot of nitrous to each cylinder for a total of 450 HP at the flip of a switch. Does it work? Does a cat have a climbing gear?

Getting back to the original "Assuming you have a driver adjustable waste-gate to control the boost of the engine, can you drive on a lower octane fuel??" Sure you can. I have a driver adjustable waste-gate on my racer and I dial in what I need to smoke whoever is in front on me, then back it off to save the engine..
Hope this answered your question....
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Don L 1157 Date 2008-11-27 04:18
Mel,

Your a man after my own heart!!  So, I have some reading about toluene (as in TNToluene), as well as alcohol and water injection.  I've got a buddy who's been talking water injection for a couple of years, but we've never done anything except speculate!! 

Next question....how much horsepower will the standard Subaru transaxles handle without spontaneous disassembly??  ;-)  Yeah, well, I'm a high school teacher, there's not a whole lot of extra $$.
Don in the Mountains of West Virginia
By Mel Adjusted Date 2008-11-27 06:00 Edited 2008-11-27 06:03
Next question....how much horsepower will the standard Subaru transaxles handle without spontaneous disassembly??

I really have no idea how much power they'll handle. I have one car thats running on hi-boost over 500 HP and never had a problem with the transmission. My transmissions have been converted to a mid-engine set-up.
I was blowing 5 and 6 rib bus transmissions like crazy... I use to buy every bus transmission I could get my hands on....Not any more... The Subaru transmission is really tough... If you know anyone how needs a 5 rib I have one left...

As for the W/A set-up the best on the market is... http://www.alcohol-injection.com/forum/   These people will answer ant and all questions you'll ever have... Water/Alcohol injection will blow the doors off a intercooler for cooling intake air temps.... I run a 50-50 mixture of it... it also raises the octane rating of your fuel...
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Jay H (X-20) (ManxVair CC) Date 2008-11-28 15:36
This is steering you away from Subaru a little bit, but google SAAB APC system, People have been robbing SAAB's of their APC systems for years to run all kinds of different engines.
By Don L 1157 Date 2008-11-28 18:45
Thanks for the information, and thus, encouragement!!  It's nice to have folks who are willing to share the wealth.

I'll be starting a new thread outlining my buggy aspirations.
Don in the Mountains of West Virginia
By Mel Adjusted Date 2008-11-30 17:10
I understand the APC system and for normal driving is great, but I'm not what you'd consider a normal driver. I fact some have said I'm insane. Thats not true according to my doctor. He says I'm almost normal.

Saab's APC (Automatic Performance Control) is an electronic turbo boost control system that adjusts maximum boost pressure as a function of engine knock (detonation) and RPM.

I would rather have total control of my boost and it's anti-detonation systems than be limited to a set system.
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Jay H (X-20) (ManxVair CC) Date 2008-12-03 14:59
Albert, I hear what you are saying about control over your system. I posted the suggestion to Google the APC system based on the fact that the original thread was asking about the ability to utilize different octane fuel. While you'll be running race fuel and manually adjusting to that octane, the nice thing about a completely automated system is that all you have to do to "adjust" the system is to grab a different fuel nozzle at the pump.. or rather, the system adjusts to the fuel, so the drivability of running a system like this with no need for manual control, is you can have high performance when you want it, or fuel mileage, and lose no fun/driving/cruising time adjusting the system.

Jay
By Mel Adjusted Date 2008-12-08 06:55
I'd like to put one of them systems on my street car...sure beat what I'm using now...
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Jay H (X-20) (ManxVair CC) Date 2008-12-08 22:03
OK, I'll bite... What are you using now? :-) I read about your switch in the injection thread just now.... Are you running dual maps?

Jay
By Mel Adjusted Date 2008-12-08 22:14
My stret car has dual maps..... My Subaru racer has Quad maps switchable on the fly.
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By dewayne b 1137 Date 2009-05-05 08:06
Mel i guess your the man to ask this question. i just got the turbo on my 2.5 na and like you said it is running great. i may need to design some wheelie bars though, it's hard to keep the front end down. so on to the question. right now i'm running 104 race fuel and at $7.50 a gallon my cruising the streets looking for a race has been severely cut back. i have purchased a snow stage 2 water meth injection but i am a little afraid to put it on and jump straight to pump gas. how much of an octane gain can i get from this. everything i read has numbers from 100 to 120. i live in houston and our super unleaded is 93 octane so what kind of water meth mix do i need to get to 104. any help you can offer would be great for me and bad news for all those vette's running the streets of houston.

By Mel Adjusted Date 2009-05-05 08:49
Now for water/alcohol injection 101...Without going into alot of detail here I suggest if your interisted in W/A injection go to this forum and you will get everything answered and can ask questions...I believe in W/A injection as one of the most important add-on's for a turbo'd engine.
http://www.alcohol-injection.com/forum/

This is the most accurate nozzle calculator out there
http://www.alcohol-injection.com/forum/nozzle-size-calculator/alcohol-nozzle-size-calculator-351.html
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Mel Adjusted Date 2009-05-05 09:05
As for the wheelie bar problem...it only gets worse. It really freaks out a vette owner when you pull a 4 foot wheelie.
I have a sign on the rear of my car... It says, "The Surgeon General says, "Smoking V8's is OK". It really pisses off V8 owners...
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
By Mel Adjusted Date 2009-05-05 15:53
First off run 3 oz. Acetone per each 10 gallons of gas. Forget racing fuel and use Toluene, which is nothing more than paint thinner but in reality is pure gasoline, like 117 octane... You'll have to do some googling on "Toluene" and "Rocket Fuel". I use to run stright Toluene In my racer to qualify it. I'd up my boost to 75#.  I was getting like 1,000 HP per Liter with this combo.Im not sure but I think you need to mix 1 gallon Toluene to 4 gallons 91 octane to get 103 octane... Google it then do a post on your findings on DBA....
At my age.. Everything I buy comes with a lifetime guarantee..
http://mel-adjusted.zoints.com/
Previous Next Up Topic Engines / Subbug - Subaru Power / Turbos and Octane (13800 hits)

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