Turbo manifold

goodburbon said:
Durability and longevity all depend on the material he uses. I'm not saying the design won't work, but that special consideration should be given when choosing material.

Edit: I really should have spelled that out in my first response. I didn't mean it WILL crack. My fault.
Click to expand...

im making it out of .88 wall HREW
 
You need to fab a turbo support off the block. My Turbo dodge has one that helps hold the weight of the turbo so the manifold doesn't crack. Is this for offroading or speed? If its for offroading a smaller turbo would spool fast. My stock turbo was a tiny mitsu started spooling at 1800 or so. Now the garrett
I have doesn't start spooling until 2500-2700 rpms but builds boost all the way to 6200rpms.
 
MogifiedXJ said:
That's what I was thinking. I wonder what his compression ratio is right now, naturaly aspirated???
Click to expand...

9.8:1, going to be 13.8:1 under full boost (6psi). everyone thinks its way to high, but for such low boost, its really not.
 
tealcherokee said:
9.8:1, going to be 13.8:1 under full boost (6psi). everyone thinks its way to high, but for such low boost, its really not.
Click to expand...

I didn't realize you were running such a low boost, you're still going to move a large volume of air with that big ass turbo though. Throw in some dish pistons, reinforce the bottom end, O-ring the head and block, and crank the psi up on that thing. By the way are you running studs on the head???
 
MogifiedXJ said:
I didn't realize you were running such a low boost, you're still going to move a large volume of air with that big ass turbo though. Throw in some dish pistons, reinforce the bottom end, O-ring the head and block, and crank the psi up on that thing. By the way are you running studs on the head???
Click to expand...

I'm building a 5.1L stroker, thats going to be running the same size turbo, w/ a clifford head, at about 15psi, looking for 600whp.

this is just my test motor and jeep.

I'm running grade 9 bolts for the head, i like them better than studs
 
tealcherokee said:
I'm building a 5.1L stroker, thats going to be running the same size turbo, w/ a clifford head, at about 15psi, looking for 600whp.

this is just my test motor and jeep.

I'm running grade 9 bolts for the head, i like them better than studs
Click to expand...
That sounds impressive. Have you checked out hescos new aluminum head? I don't know how it would do with 15psi under it though. Why a clifford head? I'm not sure I've seen one of those...
 
tealcherokee said:
lol, sorry man, hesco head, clifford carb intake

ditchin EFI
Click to expand...
Three two-barrel webers would look nice hangin of the side of the block. It would be easy to fab up an intake for them. I don't know how they like the boost though.
 
Last edited:
tealcherokee said:
9.8:1, going to be 13.8:1 under full boost (6psi). everyone thinks its way to high, but for such low boost, its really not.
Click to expand...

SPOBI

Sorry, but I have to chime in here, because it always bugs me when people talk about having a different compression ratio under boost. BOOST DOES NOT CHANGE COMPRESSION RATIO!
Compression ratio is calculated based on cylinder volume at BDC vs. cylinder volume at TDC. (Bore, stroke, cylinder head volume, and piston dish volume are used to figure this out.) None of these things change under boost. Compression ratio is a function of volume, boost is pressure; they are different.
 
He may be referring to "effective compression" - which is a function of boost. I don't recall how it works (and I don't have the book handy at the moment, or I'd explain it,) but it is a real phenomenon.

However, the "basic" or "geometric" CR of the engine does not change, unless you change something within the acting cylinder (head dish dims, piston dish/dome, bore size, stroke.)

Effective compression ratio, however, is a function of several other things. For instance, you can build an engine combo with a "basic" or "geometric" CR of 9.0:1, but that can be changed (always to soemthing lower than 9.0:1) by changing camshafts, for instance. The key there is the timing of the "Intake Valve Closing" event. I believe I cover this in my book - but I'll add it as an update if I haven't (gotta finish the Tech Archive updates first...)

5-90
 
I'm keeping an eye on this one. You cats are getting pretty wild with the forced induction. How much of an over-bore are you using to achieve the 5.1 displacement? 258 rotating assebly or something totally one off? If those cylinder walls are getting as thin as I'd assume they are, then that 600 whp (which would translate to over 700 at the fly) and 15psi is really going to be testing the structural limits of that block.

Nonetheless, I'd really, really, really love to watch/listen to a dyno pull when you get around to it.
 
OT said:
Sorry, Jon.
Here ya go....
http://www.motorsportsdigest.com/tech/forced2.htm
Click to expand...

Oh - no trouble understanding here. I've probably got the theory in a couple of books (remind me to send my my "list of references" sometime...) I just wanted to see it explained for everyone else...

As far as "high-boost" engines, you're probably going to be better off with a RENIX block (I've had the opportunity to "sonic check" RENIX/GEN-I HO/GEN-II HO, and I'll have to see what I did with those figures...) and the casting walls got progressively thinner. I remember hearing that Mike Parrish (formerly of Accurate Machine) had bored a RENIX block out to 4.000", and the RENIX block I checked would still have had something like .175" of cylinder wall all around - with the "accepted minimum" for boring a block being .100". Intereting to think that a RENIX block might be able to handle what would be oversize SBChevvy pistons, no?

I'm also hoping to get a little more out of Flatlander Racing on their stroked 258 crank - 4.145" stroke! Just imagine what we could do with that... If anyone else would be looking for information, please write requests and email them to me, and I'll include them with the next letter I write to them (once I get a few other things done - which will allow all of you to formulate your letters...) Previous communications with them said "that it would only work in the AMC258I6, since that's what we developed it for," but if it fits the 258, I'm sure it can be made to fit a 242 - and 4.000" x 4.145" = ~312cid! I would be honoured to design other components (like pistons, and possibly cams) that would make something like that well-behaved at cruise, but a torque MONSTER off-idle! So, the more help I get from you in terms of requests, the more information I might be able to develop (and share!) from them.

5-90
 
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