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Twin cam head for the L6 from Derek at Datsunworks


Derek

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Speak for yourself big boy. I'm 6' and a buck sixty wet:)

Jeffer949 will back me up!

Man your still at 160lbs.  The past 10 years haven't been as good to me. Well actually the past 5 months haven't been good to me. I've gained 20 lbs in the past few months. I went from the best shape in my life last summer to the worst shape this summer. Ahhh life. Always thwarting my progression.  And the head is looking amazing. If I ever make it down to Florida for a vacation I will have to stop by and visit. If only my company didn't use a distributor in Florida I could schedule a business trip to visit a dealer or two. 

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When you're spending 5k+ on an engine, transmission adaption becomes "easy". T56 has been done, and it's far from hard.

 

According to the guy who did it, it seems like a lot of work aside from sourcing a Datsun T5 trans for the bell housing alone.... That Z32 adapter is looking a lot nicer than this... Someone needs to get on Hoke to make more of those adapter plates or at least publish the cad files so we can make them ourselves if hes stuck on not making them.

 

"The problem is that once the Datsun T5 bellhousing is bolted to the adaptor, a Datsun T5 front bearing retainer will be needed. The issue from this point is that the T56 input shaft does not reach the back of the crankshaft, or even the flywheel so the T5 bellhousing was milled and welded to an aluminum adaptor plate and a GM pilot bearing was placed in the aluminum flywheel. It is more than a simple bolt in as the steel adaptor and the T5 bellhousing would both have to be milled"

 

I dont mean to digress from the great work Derek is doing, but this is a real concern I have and just want to understand the options that are available before 10k+ is spent on this kind of setup.

Edited by AZGhost623
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I wish someone would make an adapter for the bmw getrag transmissions several E30's and E36's running 400+ft tq setups with the stock trans, mine soon to be included. And they're plentiful and cheap.

For a turbo setup, you're talking about WAY more than 400lb-ft.  This is going to be 600lb-ft at the flywheel at an absolute minimum.  Finding a clutch for this will also be challenging.

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Well the nice thing about my conversion is it still uses the stock L6 block. So anyone making the investment in producing and adapter won't be tied to only the people that run my head. I will throw this out though. I have made bell housing patterns and I have made one for a similar application. If the lack of a strong enough transmission is holding back head sales I will look at this. I've kicked it around a few times. I'm not a big fan of spacer plates on the flywheel so a custom bell housing appeals to me. But I haven't done any research beyond the absolute basics. 

 

I do know one thing though. I'll probably blow my whole drive train on the first dyno run. It's old and tired like me. 

 

I'm happy to have this conversation but I think it's probably best to move it elsewhere and link to it from here. As it is a separate thing.

 

Derek

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Ok

I want to share this link. I don't want anyone to comment here because I really want to keep this thread about my head. But this video sums up what doing research on K20's on the internet can be like.  It's a honda but not a K20. But the sentiment is the same. I made a post on the general non tech board.

http://forums.hybridz.org/topic/123840-video-sums-up-what-researching-a-honda-k20-head-is-like/

 

No replies here please:)

 

Edit: fixed link

Edited by Derek
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Well the nice thing about my conversion is it still uses the stock L6 block. So anyone making the investment in producing and adapter won't be tied to only the people that run my head. I will throw this out though. I have made bell housing patterns and I have made one for a similar application. If the lack of a strong enough transmission is holding back head sales I will look at this. I've kicked it around a few times. I'm not a big fan of spacer plates on the flywheel so a custom bell housing appeals to me. But I haven't done any research beyond the absolute basics. 

 

I do know one thing though. I'll probably blow my whole drive train on the first dyno run. It's old and tired like me. 

 

I'm happy to have this conversation but I think it's probably best to move it elsewhere and link to it from here. As it is a separate thing.

 

Derek

Agreed - I wasn't trying to throw a wet blanket on the head. I was getting the distinct feeling that people weren't realizing the extent to which this is a whole different world when we start talking about using it in a serious turbo setup.  

 

Anybody that would actually be considering doing this should already be aware and willing to spend the money/effort, or they'll find out really quick just how far in over their heads they are.  I'm waiting to pick up a head really cheap from one of those guys...  :mrgreen:

Edited by TimZ
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so pardon my ignorance here... but with all this potential torque the engine can produce, what kind of transmission options are available to handle this? Its not like collins adapters has plates for an L28, and hoke has been out of stock on the Z32 adapter plates for sometime... The B boxes might work fine for a while, but repeated abuse will take its toll alot quicker on those. Longevity and reliability through repeated abuse is the issue I would think. SX C boxes are getting harder to find because the drift crowd is beating them to death.

 

I dont see anyone making 350/370Z trans adapters either... so what are the options for a good trans to mount to the engine with this setup?

 

 

Kameari makes a forged gear set for the fs5w71b....it costs alot but im sure it strengthens it up

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Kameari makes a forged gear set for the fs5w71b....it costs alot but im sure it strengthens it up

I think Derek wants this stuff to go in another thread, so this is the last time I'll mention it here.  Kameari gives no torque ratings and I'd be worried that it won't be enough given that it's based on the fs5w71b.  I know they make good stuff, but I'm not sure that this is what they had in mind for that gearset.  It would likely be a _great_ solution for a high output NA setup using this head, though.

 

This will likely be borderline too much for a Gforce T5 (500lb-ft, 600hp in a 3300lb car with drag slicks).  If you can figure out the T56 fitment (it's been done), Gforce has a gearset for that, too.  It's rated at 1000lb-ft, 1200hp and should be enough.

 

Also you'll probably want to consider dog-ring synchros if you are going to want to be able to shift at 9000+rpm.

 

Again -  whole different world.

Edited by TimZ
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I simply can't imagine how much this will move the surge point in the RPM range for the "big boys" turbos. On a conventional wastegate setup this could very well be making boost in HALF the RPM compared to a stock Nissan head of any kind, and wouldn't get mad at you for creating 15psi by 2,000rpm. But really, even 15psi on this head is looking like a 700+hp engine, which means we're talking BIG turbo requirements. I'm thinking something in the GT47 size range with a turbine AR down sub 1.00. Should spool that sucker in no time, and you're not trying to get 1200hp worth of air out of it

I'm pretty sure that's not how this is going to work.  

 

I would not expect to see much if any difference between this and a well-prepped n- or p-series head until you are beyond _at least_ 4500rpm (probably higher).  The huge difference comes into play when you realize that you can hit that 600lb-ft torque peak at maybe 6000 rpm and then manage to hold that peak out to 9000 or higher.

 

That's where the huge power happens -we would be talking about over 1000hp at the flywheel in this case.  For real.  

 

You should _not_ expect a GT47 (min turbine AR is 0.96) to spool before 6000, even with a 3.4 litre.  That's a really big friggin' turbo!  Not for the faint of heart.

Edited by TimZ
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Kameari makes a forged gear set for the fs5w71b....it costs alot but im sure it strengthens it up

 

Not really. The gearset does not usually break first in the 71B/71C transmissions...it's the front countershaft bearing and then the rear mainshaft bearing that goes.

 

The stock gearset is forged as well...

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For a turbo setup, you're talking about WAY more than 400lb-ft.  This is going to be 600lb-ft at the flywheel at an absolute minimum.  Finding a clutch for this will also be challenging.

 

I was saying the trans can hold up to these levels in boosted applications in e30s, so it should be fine here in an 

n/a scenario. I wouldn't want to boost an engine with this head. From what it should be capable of in a higher compression non-boosted car it will be plenty. You'd have to build the car around the engine like they build A-10 warthogs around its cannon. 

 

I can't wait for this to come to fruition, I'm picking up and building a 240z just for this head. I can't wait!

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Turbo work most people do is oversized on the A/R for the hot side anyways. 

 

I think you will be able to use quite a bit smaller scroll and get very good spool from it. I don't think it will need to go to 6K to spool.

 

The flow / lift numbers are staggering. Were this head to go onto an existing build (which I think this is what was being talked about) the numbers  you would see on the intake side would plummet from the better flow, and the spool would not change. The flow through the engine would accomodate the power without the ills seen when you make big boost numbers to reach the same HP levels.

 

It's as I told JeffP (just for me, let's do one pull at 8 psi first, and see where the cam peaks...) Well, he still doesn't know because he got greedy right away and ran 17 or 20 something and found out the turbo went into stonewall...when it went into stonewall (rpms) was based on pressure. And as would be expected the HP remained the same. Just progressively lower rpms as the boost was wicked up.

 

More people should really check their exhaust pressures and see if they are losing power under the curve by thinking they need a humongo A/R on the exhaust side.

 

What this does open up, though is some turbines with PWM Variable Vanes and Nozzle Rings.... This engine now will pull the rpms to where you could exploit a 1.06 A/R diesel turbo on the top end, and use the VNT to choke down for lower rpm boost assist...

 

Tranzilla comes to mind immediately. And, for those drag boys...juiceboxes... they're quick... even with turbos!

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Turbo work most people do is oversized on the A/R for the hot side anyways. 

 

I think you will be able to use quite a bit smaller scroll and get very good spool from it. I don't think it will need to go to 6K to spool.

 

Agreed - I was referring to assuming that you'd be able to get a GT47 (or something similarly huge) to spool at lower rpms.  Problem with these turbos is that they generally don't make them with ARs below .96, and that's with a T4 housing.  I've not seen anybody offering "Frankenstein" GT4x series turbos with small hot sides.  So, yeah - I don't think you are going to spool one of those at much below 6000.  Maybe 5500, but certainly not 4000, let alone 2000.

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"Problem with these turbos is that they generally don't make them with ARs below .96, and that's with a T4 housing. "

 

Well, then again three years ago there wasn't an alternative DOHC Head Casting available for an L-Series outside Japan, either...

I mean, it can't be any more difficult a modeling and casting exercise, and there are plenty of places with 5-axis mills to do the finish machining...

Mowhahahaha!

 

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