Combustion Chambers,Octane and methanol.

[TheSwede]

Hi...and hello.

 

Sitting here contemplating the coming winters engine build.

 

First up a question for all you americanos.... whats the octane ratings on your pump gas?

The reason why I´m asking is a discussion some months ago on this forum,

about me building an L28 turbo engine with aprox 300 crank hp without water/methanol injection.

 

The answer i got was that the for example p90 head had combustion chambers that was supposed to lower Nox emissions, and beacause of that they are prone to pre ignition and knock.

Not that I really have that one figured out yet, since Nox is created from high compression and high cylinder temperatures, actually thoose heads shouldnt be that bad. Well well...

 

 

Ok, now back to the question about the pump gas.

Cause i kinda have an idea. The soup you can buy at the stations here are 95,98 octane gasoline and E85 wich is ethanol, about 107 in actane rating.

 

Using the E85 would keep my pretty much on the safe side.... that along with a aftermarket ecu system, intercooler and so on.

 

Thought and ideas anybody?

 

/PJ

 

PS: And as always when im writing in english, please excuse my spelling.

[rsicard]

Newbie:

 

Purchase David Vizard's latest performance book and follow suggestions contained in same before starting on engine rebuilds.

[johnc]

In the US, octane for pump gas is an average of the motor and research octane numbers. The number tends to be lower then in other places for the exact same fuel. Typical US octane numbers for Premium are 93 to 91. The P90 head tends to do better combating ignition and knock then most of the other L6 heads. If you're building a 300hp L6 engine then a lot of headwork will be required and you'll probably be welding up the chambers or running a domed piston of some kind. in that case you can design/build whatever combustion chamber you want.

[TheSwede]

Thanks for the input johnc...

 

And ill be checking that book out from wizard, when its realesad here in sweden... semptember i think.

 

BTW...A stock L28et produces 200bhp right? But at wich boost level.... about 0.6-0.7 bar or some like that. (10psi kinda)

 

Bloody he%&, my last build were a 400bhp saab 9000 2.3t on stock internals and without any head work.

But ok, thoose engines are like 20 years younger and known for there ability to take abuse.

 

 

cheers

[BluDestiny]

I think john thought you were going with an Non turbo engine. High Compression and all that because you were talking about octane ratings and knock and stuff.

 

swede, You can get 300hp out of a turbo motor with a better turbo, intercooler, injectors and an aftermarket engine management system with no engine work whatsoever. Stock L28ET makes 180bhp on 7psi. With the mods I listed you can make it up to the mid to high 300's easy on pump gas. Then you

Edited August 12, 2011 by BluDestiny

[johnc]

Oops!

[TheSwede]

ah..... now its starting to sound a little more close to the real world. hehe

 

Perfect, cause my plan was to use my Nira I3+ ecu, a proper intercooler in the front, with all the little gizmos from saab when it comes to fuel injectors and such....they work real well with the ecu u see.

 

 

Down below is a link to some pics from my latest project, its in swedish but just klick the pictures down in the right corner of the page, thats the sucker who ended upp with 400bhp ... a nissan 200sx with a saab 2.3t engine and

a opel omega tranny.. so u guys can see the whiskey induced madness i´m in...

 

http://www.garaget.org/mypage/gallery.php?user=88383&album=12958

 

Cheers

 

/P-J

 

PS: By the way, the person soldering the cables for the Ecu in the pics is my old lady Emma....love her from the bottom of my crankshaft heart..hehe

Edited August 12, 2011 by TheSwede

[Gollum]

The 300 wheel HP mark is so easy to hit with a Turbo-L setup that it's been done quite a variety of ways. That being said, one of the most asked questions on these forums is "can/how I make 300hp with my L28ET?" It's actually quite frustrating how often it comes up. It's like space invaders. It doesn't matter how hard we try they just keep coming!

 

I've seen people do it with the stock turbos. Others that did it with the stock ECU. One guy even did it with stock injectors running over 100psi.

 

The beauty is that 300hp is the sweet spot in which it's quite difficult to blow it up unless you've got some serious tuning issues. You can reach 400 without reaching the limits of the internals, but tuning becomes a knife edge extracting that much power as slight detonation can become catastrophic.

 

On the topic of octanes, I'd just like to state that the octane number isn't a whole complete picture. Ethanol and Methanol aren't just higher octane than pump gas (meaning it burns slower) but they also are able to hold more heat, thus cool the chambers more than gasoline/petroleum fuels do. The both also have a wider air to fuel swing they can operate in (when considering percentages, not numbers). This means that though you need more fuel to reach rich best torque, lean best torque will be a much further swing down than petroleum fuel would be. This is great if you want to spend the hours tuning the low load areas of your map, as you can recoup a lot of the lost MPG in the cruising ranges, giving you nearly the same MPG as you'd have on petroleum, and it's usually cheaper fuel in most parts of the country.

 

It's actually almost humorous to watch someone's first experience with tuning E85 or meth, because it's just ridiculous how much further you can push the timing, even before fine tuning the map.

 

For example, the STI will make roughly 300 whp on pump gas with the stock turbo here in CA (in most cases), and switching to E85 you can get so much extra timing out of the engine because it's running so much cooler that without adjusting the boost, just getting the fuel and timing set close you'll pick up over 40 whp. Then you'll be able to up the boost into new territory you couldn't touch before getting more power even still! When you crunch the numbers this is a LOT more power to be gained than just the "extra energy" contained in E85 at stoichiometric levels. You get a slower burn/higher octane which allows for more aggressive timing. You get a cooler chamber, which allows for even MORE timing, or more boost. You also get more fuel in the chamber per cycle with more energy, thus more power! In the example mentioned, a STI pushing around 300hp on CA premium, with large enough injectors will be able to gain up to around 100 wheel HP when switching to E85. It's THAT much of a difference. And of course methanol is just more of the same as E85, but with an edge. You can also do E85 or meth as a secondary injection system, spraying it only when under boost, which gives you all the benefits when it comes to getting more power, while still maintaining the MPG of petroleum plus unchanged starting characteristics (it's much harder to get a low compression engine to start on E85 as it's so much less volatile).

 

All that said, E85 is complete overkill for just 300hp.

 

 

Regarding chambers, there's tons of info on this site, but most agree that the P90 is certainly one of the better heads to choose from, especially for force induction. You can even put the P90 on top of a motor with flat top pistons, which gives you basically a 81-83 280ZX NA motor but with square exhaust ports and no exhaust liners. Despite the "higher compression ratio" it's still only around 8.8:1 iirc. It's still plenty low enough to reach 300hp without serious danger of detonation. It might be a bit harder to reach 400hp without extreme care, but 300 is still perfectly doable on pump gas as long as you have good tuning ability with an aftermarket ECU.

 

I'm gonna stop talking now because all of this has been covered many times over, and I'm simply tired of typing.

[letitsnow]

You should be able to make 300 crank hp with the stock turbo, you'd be pushing it a bit, but it should do it.

[Tony D]

"The 300 wheel HP mark is so easy to hit with a Turbo-L setup that it's been done quite a variety of ways. That being said, one of the most asked questions on these forums is "can/how I make 300hp with my L28ET?" It's actually quite frustrating how often it comes up. It's like space invaders. It doesn't matter how hard we try they just keep coming!

 

I've seen people do it with the stock turbos. Others that did it with the stock ECU. One guy even did it with stock injectors running over 100psi.

 

The beauty is that 300hp is the sweet spot in which it's quite difficult to blow it up unless you've got some serious tuning issues. You can reach 400 without reaching the limits of the internals, but tuning becomes a knife edge extracting that much power as slight detonation can become catastrophic."

 

Amen, Brother!

 

1985: Bosch Dyno Tuned the stock 24,000KM 1977 Nissan Cedric L28 to 348 RWHP and ran it until I scorched out my last turbo, and then decided to let the car rest... That was over 40K miles of HARD driving on a BONE STOCK engine. It was the 'minimum price of entry' if you wanted to be considered 'credible' in Japan in the mid 80's. By the time the 90's rolled in, with electronic fuel injection the price of admission went higher. Heck, Frank280ZX took Yetterben's old HKS Blow-Through setup and bolted it onto his dad's Eurospec 280ZXT and cranked out 248 HP at the rear wheels as I recall (there's your crankshaft horsepower...)

 

Maybe we just need an FAQ post entitled "I want to turbo to 300(Crank/Rear Wheel)HP on my L28, what do I need to do" and then when you click on it the screen flashes saying "NOTHING, JUST ADD BOOST AND FUEL IT RIGHT!"

[kolonelklink87]

 

1985: Bosch Dyno Tuned the stock 24,000KM 1977 Nissan Cedric L28 to 348 RWHP and ran it until I scorched out my last turbo, and then decided to let the car rest... That was over 40K miles of HARD driving on a BONE STOCK engine. It was the 'minimum price of entry' if you wanted to be considered 'credible' in Japan in the mid 80's. By the time the 90's rolled in, with electronic fuel injection the price of admission went higher. Heck, Frank280ZX took Yetterben's old HKS Blow-Through setup and bolted it onto his dad's Eurospec 280ZXT and cranked out 248 HP at the rear wheels as I recall (there's your crankshaft horsepower...)

 

Tony,

To my understanding the 77' 330 nissan cedric had no turbo option... ?

Even in japan I've seen very few turbo cedrics, some y30s i think had a turbo option?

 

Cheers,

Pete

[ozconnection]

Tony,

To my understanding the 77' 330 nissan cedric had no turbo option... ?

Even in japan I've seen very few turbo cedrics, some y30s i think had a turbo option?

 

Cheers,

Pete

 

And you're asking who?

 

L20AET's were in some 331's

[TheSwede]

Thanks for the input guys...

 

 

Can imagnine im far from the first to ask the question about 300hp turbo...

 

But since my forum searching skills are far from perfect, I just became the last wave of space invaders to bug you guys...

 

 

Thnaks again.

 

PJ

[Tony D]

It was a standard 77 L28 from a Cedric with an automatic. It has an N42 head with no injector cutouts nor injector manifold mounting holes. The point being it was a standard 'high compression' L28 and it worked just fine to make that kind of turbo horsepower. Nothing internal was done, it was all purely bolt-on goodies to get the power level to that point.

 

Mid 200's is child's play on a turbo! These guys stress too much after reading misinformation on the interwebs...

[rayaapp2]

I nailed the 322hp mark in my L28et in my 260Z. It blew 2 years later due to a CAS failure(crank trigger heat soak). I lost the ring lands and cracked the piston skirts on #6. It had a highly modified ECCS system on it along with a custom fuel system capable of supporting that power. My base timing was good, but as soon as I started messing with the throttle the timing would jump all over the place. If that hadnt happened Id probably still be running around with that setup and not the RB. I ran US 91 octane in it. Fueling it and messing with the timing curve was all I really had to do. It was all on a stock Turbo... and I dare say it: NO INTERCOOLER!(stock Jpipe, stock TB and stock intake). I did have a custom 2.75" diameter 2.5' long exhaust dump from the turbo. I probably could have installed a nice intercooler and modified a few things and made slightly more but the car felt ridiculously fast for a DD street car. When you can drop 5th gear from a stand still and proceed to do a burnout your tires are to thin and the car becomes a little unwieldy(195/60R14).

[Gollum]

I nailed the 322hp mark in my L28et in my 260Z. It blew 2 years later due to a CAS failure(crank trigger heat soak). I lost the ring lands and cracked the piston skirts on #6. It had a highly modified ECCS system on it along with a custom fuel system capable of supporting that power. My base timing was good, but as soon as I started messing with the throttle the timing would jump all over the place. If that hadnt happened Id probably still be running around with that setup and not the RB. I ran US 91 octane in it. Fueling it and messing with the timing curve was all I really had to do. It was all on a stock Turbo... and I dare say it: NO INTERCOOLER!(stock Jpipe, stock TB and stock intake). I did have a custom 2.75" diameter 2.5' long exhaust dump from the turbo. I probably could have installed a nice intercooler and modified a few things and made slightly more but the car felt ridiculously fast for a DD street car. When you can drop 5th gear from a stand still and proceed to do a burnout your tires are to thin and the car becomes a little unwieldy(195/60R14).

 

Just to clarify for people so we don't start any more internet myths than needed, which CAS setup where you using? The stock 81 turbo, 82-83 turbo, or a later 300zx turbo cas?

[tyler031734]

When you can drop 5th gear from a stand still.

 

 

Sorry, couldn't stop myself....

Edited August 26, 2011 by tyler031734

[rsicard]

The Swede:

 

David Vizard's book: http://www.amazon.com/David-Vizards-Build-Horsepower-Design/dp/1934709174/ref=cm_cr_pr_product_top

[rayaapp2]

Just to clarify for people so we don't start any more internet myths than needed, which CAS setup where you using? The stock 81 turbo, 82-83 turbo, or a later 300zx turbo cas?

 

The one that is now pretty infamous for failing in that exact way. The 81 Crank mounted CAS. It just sits there and cooks until it fails. If I had been a bit smarter back then I would have used the 82-83 CAS and addressed some of the heat issues. This one is no internet myth. There is actually a lot of information on those problems with the 81 CAS. For some reason the later CAS in the dizzy housings are either less susceptible to the the heat soak or the dizzy housing itself does not transfer as much heat into the components because of its location or whatever. I was barely getting the timing out of that CAS that I needed anyway. I needed a fully programmable timing curve. This happened back in early 2006 I believe.

Edited August 26, 2011 by rayaapp2

[Gollum]

That's all exactly what I expected you to say ray, I just didn't want to say it for you.

 

But it's when things like this aren't clarified that some noob will get it in their head that the 82-83 CAS system is bad too!!! The good news is that all the information is available here on this site for those that are willing learn facts, not just myths.