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big and nasty headwork


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Hmm, I think I struck a chord, and I think it was a C#m13... ;)

 

Seriously though, the day I find a woman that can tell me what SCSI stands for, knows the difference between 4 flats and 4 sharps, and isn't afraid of getting sideways in a car I'm proposing.

 

But alas, I'm too young to think of such things. I've got too many things on my plate as it is. But I DO vote that braap's post should be posted as a sticky.

 

EDIT: Do I even have a vote? I tend to think I don't have any power on this site... but maybe I do... ;)

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Silent' date='

 

True, "rude" is subjective. I said you were because you gave me attitude after I said something that you already know. Well how am I supposed to know what you already know then? This is small stuff, it's not that important, just when I read your response, for a moment it felt like getting a rain of piss for trying to help.

 

A local guy(owns a bodyshop) here built his 240Z with all fiberglass exterior(hood, fenders, hatch, doors) except the roof. He was using triple Mikunis and runs 12.9. Car has centerforce clutch, and of course cam and engine works. The details of which I don't know. He only said he spent a lot of money on the engine & drivetrain. However the car still has regular glass on it and is still streetable. If you build a dedicated drag car with a stroker then there might be a chance.[/quote']

 

 

im glassing the front half of the car, fenders, buckets, hood, airdam. that sort of thing. the motor is a stroker already, so that apsect is taken care of.

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Where you run pistons like this:

 

cyl4.jpg

 

You can open up the combustion chamber and unshroud the valves for better flow like this:

 

SunbeltHeadCC.jpg

 

That makes more power then building up the combustion chamber and shrouding the valves.

Weird. They didn't notch the block at all, and didn't take very much metal away around the head gasket area. All the work is in the chamber. From the looks of the chamber it makes me wonder if they wouldn't have been better off starting with the open E88 chamber head.

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holy hell batman' date=' that was what i was pretty much looking for. someone who knows something about nissan heads. what it would take to get it to the zone im looking for.

 

as it sits, im running a 3.1 stroker, with a fully balanced bottom. put down a measly 192 rwhp in the summers heat. {measly coompared to my older 400+ awhp dsm's}

 

i have three heads at my disposal. early e88, late e88, and a N42. of these three heads, which would yield me the best all out nasty race prepped. 45mm+ triple carbed race engine. and what would the range of price be?. if say, i sent "braap} the head to do. because no one here in town has a clue about them anymore. i'll supply the valves, springs, seats, and cam, either a 560 lft, 300 dur. or a 620lft 304 dur. as you can tell, im not going to daily driver here.

 

i have been told by a couple people the early e88 would be best, and others the n42. im still researching things here and there. there is no class limit on what i want to do. the engine will probably be pulled this winter, and gone through, rings, bearings, stuff of that sort. im not looking to spin the motor to anything above 9 grand {diesel crank doesn't like this}[/quote']

 

 

 

how much torque ? hp is not all that comes up with higher compression

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Silent,

I would be glad to give you my opinion on which head to use and work up a quote for your project. You can contact me off forum @ either of the 2 E-mails below;

 

braapZ350@hotmail.com

 

ruschmotorsports@hotmail.com

 

 

Gollum,

Uh, well I think my wife about covered the “Daughter” thing.. LOL Nice try though…

 

 

Thehelix112,

If I understand your question correctly, you want my input on the different techniques and strategies employed when building a cylinder head for Carbs vs FI. Personally, I build them the same. The only things that would be different between a head for a carb or FI application would be maybe the mounting holes, port alignment etc, for the manifold being used. Port work, valves, cam, etc, would be the same for a carbureted or FI head.

 

 

John Coffey,

Thank you for the link to your car. Very nice Datsun you have there. It is quite apparent that you set out to build the fastest Z you could while still keeping it a “Z” car, i.e. keeping it L-series powered, OE chassis design/pickup points remained, etc. You and achieved your goal with little to no compromises. Very nice. I did notice in the pictures you posted of your chambers, someone else did as well, that the chamber walls on the sides of the chambers appear to be untouched, i.e. not brought out closer to the fire ring which would unshroud the valves further, though the spark bolt side of the chamber looks great. I’m sure it is screamer. Ever take it the strip?

 

 

DAW,

Yes, there are some theories I haven’t touched on here that I would really love to try out and we have even talking about building a Test Mule L-28, (Dyno queen), for just such a purpose…

As for bouncing ideers off each other, Feel free to post me privately at either of these E-mail address;

 

braapZ350@hotmail.com

 

ruschmotorsports@hotmail.com

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Very nice. I did notice in the pictures you posted of your chambers, as someone else did as well, that the chamber walls on the sides of the chambers appear to be untouched, i.e. not brought closer to the fire ring which would unshroud the valves further, though the spark bolt side of the chamber looks great. I’m sure it is screamer. Ever take it the strip?

 

Not sure exactly whey the combustion chambers were done the way they were (I'm not an engine guy). I was limited by the rules to 3.0L and the block was o-ringed so that might be some of the reason for what was done.

 

My specific design goals for the engine was a flat torque curve and as much torque as possbile. It peaked at 262 (actually 275 in the final tuning iteration) but what was more important was that the engine developed at least 200 ft. lbs. from about 3,500 to 7,200 rpms. Rev limiter was set for 7,500 and the max rpm was 7,800. BTW... the Sunbelt cam and valvetrain design allowed installed spring pressure 25% less then OEM and it uses only a single valve spring.

 

Car weighed 2,160 lbs. but was geared for road racing (gearing/rpm limited to 152 mph but the max speed anyone say was 146 mph with Erik Messley driving it at WSIR). It would probably suck big time at a drag strip.

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Thehelix112' date='

If I understand your question correctly, you want my input on the different techniques and strategies employed when building a cylinder head for Carbs vs FI. Personally, I build them the same. The only things that would be different between a head for a carb or FI application would be maybe the mounting holes, port alignment etc, for the manifold being used. Port work, valves, cam, etc, would be the same for a carbureted or FI head.

[/quote']

 

Sorry about the misunderstanding, I meant Forced Induction, not Fuel Injection. ;) My mistake. I've never played with carbies much (read: haven't been doing this for very long)

 

Dave

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Ah, Boosted vs N/A…

Yes there is difference in how I approach a cylinder head build for boosted engines. If it is turbo charged, typically it gets all the same treatment as my N/A heads get, unless the customer wants to alter the intake to exhaust valve size ratio to bias it one way or the other, then I will also bias any work in the ports to match this.

 

For Super charged and Nitrous heads, more attention is paid to the exhaust side of the head including installation of larger exhaust valves, of course depending on how much boost/squeeze the end user wants to use.

 

You see, with a super Charger, the engine is being force fed more air into its cylinders through the intake, while in contrast, the exhaust, which isn’t getting any extra help from a pump of any sort, still has to expel the spent gasses the same way its N/A brethren does, by opening the exhaust valve and pushing it out as the piston climbs the cylinder bore, but now there is a lot more exhaust gasses to exhale being as it is super charged so we modify the exhaust to help the engine expel all the extra burnt gasses. With Nitrous, since we are introducing more oxygen to the combustion process in bottle form, the same holds true so by helping the exhaust to do its job just that much easier brings the balance of intake to exhaust flow back to a closer balance in an effort to make as much power in as efficient manner as possible, whether we are building more power from boost or with Squeeze.

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Paul,

 

Interesting. What you've said does make sense regarding the addition of oxygen (hence fuel) and the requirement of passing more exhaust gases.

 

An additional complication with turbochargers it the restriction in the exhaust flow that they pose. The exhaust side has to be balanced such that the backpressure to the head doesn't cause reversion, as I'm sure you know. Anyway, thanks for the awesome write up. :)

 

Dave

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Sounds like you have the wrong cam. Have you red the posts from Zredbaron? He went through the SAME thing you're doing now. Within 10 hp out of his 3.1 stroker if I recall...

 

 

i figured it did pretty good for SU's and a stock head.

im not worried about the head that is on the car now, nor the cam, i plan on going with a totally different upper half when it's all said and done

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thehelix112,

 

Yes you right on track. The exhaust restriction that Turbos present does require special attention when trying to extract the most performance with the least compromise elsewhere and this exhaust restriction is constantly ever changing while the engine is in operation. Even minute changes to outside air temp, to name one of hundreds of variables, can really alter things. Trying to find that balance over the broad spectrum of what is taking place within a Turbo charged engine is quite overwhelming.

In short, Turbocharged engines do bring a lot more variables to the table when it comes to cylinder head modifications vs a N/A, Super charged, or Nitrous fed engine. This is why most engine builders/tuners play it safe by not altering the intake to exhaust bias to any great extent for fear of going backwards with Turbo charged engine. For example, a tuner may have stumbled onto a particular intake or exhaust modification that may have worked for one Turbo setup, but that same mod may be way wrong for another. You could list 100+ different variables that a Turbonic power plant deals with and to be able to meet all those demands with the least compromise is well… uh…. a daunting challenge, to say the least, and us mere mortal engine builders/tuners really don’t have the budget or time needed to devote to such a project. If one did take this on just playing with one particular engine , i.e. L-28, and with the myriad of turbos, intercoolers, intake manifold designs, etc, etc, available, this could consume a lifetime of “lets see if this works” testing? LOL… I’m sure there have been some long term exhaustive documented dyno testing with Turbo L-6 engines and it sure would be nice to read those results.

 

 

Any way, thank you all for allowing me to post my views on the internal L-series 6 cylinder.

 

We know return you to our regularly scheduled Hybrid Forum…

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