Darth Vader....Your LSx Stroker is ready!!
01-22-2012, 04:07 PM
#161
Truthfully, this was my first LS street engine that I decided to try the vacuum pump on. I may or may not decide to run it when the smoke clears but I'm leaning more towards using it than not.
When I get back on the dyno in the next month or so I will finalize all the numbers and also see exactly what the pump is worth. Looks to be about 6-8 HP based on some preliminary testing but when the motor is all dialed in it's final configuration I will do some A/B testing with and without the pump and see what its worth.
Thing is every engine may respond a bit differently...the better your ring seal the less it will effect your numbers on the upside IMO.
Will keep you guys posted....sorry things are dragging out a bit with this build but there is no question in my mind that the final outcome of this combination is going to be an extremely unique and capable package (worthy of all the extra R&D time and TLC invested).
-Tony
01-29-2012, 08:19 AM
#162
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Its actually a small dome with very large reliefs.....basically it nets you negative 3 cc's like a perfect flat top with valve reliefs typically would (but you have deeper larger reliefs with this piston design). Basically I took a Wiseco K462X185 which is a pretty neat shelf piston with a GFx ring pack and I spec'ed it exactly how I wanted the ring grooves cut to work with the slightly thinner ring pack Im running. I spec'ed the groove width and depth etc. but kept the dome profile exactly the same as that shelf Wiseco I just mentioned. I prefer the dome/deep valve relief design to a flat top for numerous reasons...
01-29-2012, 05:17 PM
#163
The first is a big valve head needs a large valve relief in the piston which creates a larger negative cc piston volume. In fact consider that including the small dome this piston still has negative 3cc's net volume. I prefer to keep the chamber of the head on the larger side while still getting the final compression ratio Im looking for.....the larger the negative dome volume the more I would have to mill the head to get the CR I was targeting. That reduces available piston to valve clearance and also I find the LS heads will usually flow a little better the larger that chamber volume is so less milling of the head becomes beneficial from that standpoint as well.
Also, the dome of this piston actually smooths the flow of lowlift airflow as it exits the intake valve when the intake valve is actually positioned in the valve pocket as the piston starts heading down the bore and the intake valve is chasing it (the tightest area usually occurring at 10' ATDC where your P to V will typically be the tightest). A picture of what I'm describing here would make this easier to understand but essentially the small dome actually fills the void on the back side of the intake valve temporarily helping low-lift flow when the piston and valve are close to one another (but only during a small percentage of the intake valves filling cycle when the intake valve and piston are close to one another).
But you have to keep in mind that it's the sum of these dozens of small "details" and optimization of parts (including accurate machine work and "finicky" assembly labor) the sets apart a "good" motor from something truly special. And by something truly special I mean an engine that produces a better power and torque curve than the typical sum of its parts would lead you to expect or believe possible.
While there is no single component that carries a really strong engine, if I had to pick the most important (single) component it would be the cylinder heads without a doubt. Without a killer set of heads it would be hard to have a really exceptional piece no matter how optimized the rest of the combination was. Heads represent the largest restriction to airflow entering and exiting the combustion process and most engine builders would agree that a really good set of heads is the cornerstone of every serious build. I liken it to a really good movie where the heads represent the "star of the show", and everything else (all the other components) simply has a supporting role. But....much like a good movie, without everyone else cast just right (in the case of the engine, the right intake, exhaust, camshaft, etc.) you can still miss the mark and have an OK turnout, but it wouldn't be as devastating as not having a really efficient set of cylinder heads (or the right actor/actress to play that extremely important leading role). Did that analogy make any sense??
Heads are also an area I usually recommend people to buy the absolute best they can afford.....knowing how large an effect it can have on the ultimate bottom line (the shape of your power and torque curve), its usually best to save longer if necessary and get exactly what you need. (The real problem is knowing what that is potentially or relying on someone you trust to guide you, but you get my point.....LOL)
-Tony
Last edited by Tony Mamo @ AFR; 01-30-2012 at 08:24 PM.
01-30-2012, 02:05 PM
#166
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This is beautiful. I'm looking forward to hearing your thoughts on drivability and performance once everything is buttoned back up. And I'm definitely looking forward to those HD "in-car" vids. This sounds like it's going to be an amazing setup.
01-30-2012, 08:40 PM
#167
Trying to find 10 more HP on this engine is probably more difficult than finding 25 more on an engine that makes 100 HP less....the more you make the incrementally more difficult (not to mention time consuming and expensive) it is to make more.
The quest is half the fun though.....I'm just hoping for an OK turnout and I while I dont have illusions of seeing huge gains, I hope some of the latest time I spent will push the envelope just a little bit further.
Truthfully while I'm excited thinking about the next round of testing, I'm mostly looking forward to the day I'm sliding this engine between the fender wells of my C5 again....its been a long road and even with the power/torque curve from the first trip to the dyno, it's sure to be a wild ride on the brink of traction thru most of the lower gears!
-Tony
PS....I posted this comparison much earlier in this thread but as it directly relates to what I'm discussing thought it was worth another look and another mention. This is the 383 I removed from my car on the same engine dyno so its directly relevant information. Note the 140 ft/lb advantage in the mid 4000's where you would likely try to launch the car.....and the 130+ HP advantage upstairs is quite healthy. Then consider my Vette trapped 130 MPH with that same 383 and on Nitto drag radials had a hard time getting traction on the street. Comparison dyno first and a link to video thats been floating around for a few years that gives you guys an idea of what that engine was capable of on the street. As good as the 383 was, it will probably feel like the 454 with a couple of plug wires not connected.....LOL
Last edited by Tony Mamo @ AFR; 01-30-2012 at 08:58 PM.
02-02-2012, 12:09 PM
#171
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Hello, I am here to pick up my engine. Thank you.
Haha sorry for not providing much contribution to the thread. I do like that you are looking forward to driving it again. Sometimes we get so concerned with the build that we forget the joy of driving the end result. Not just competing and "the number" either. Just cruising down the open road at a leisurely pace... knowing when you mash the gas, the monster you built will come alive.
Haha sorry for not providing much contribution to the thread. I do like that you are looking forward to driving it again. Sometimes we get so concerned with the build that we forget the joy of driving the end result. Not just competing and "the number" either. Just cruising down the open road at a leisurely pace... knowing when you mash the gas, the monster you built will come alive.
02-02-2012, 03:14 PM
#172
Hello, I am here to pick up my engine. Thank you.
Haha sorry for not providing much contribution to the thread. I do like that you are looking forward to driving it again. Sometimes we get so concerned with the build that we forget the joy of driving the end result. Not just competing and "the number" either. Just cruising down the open road at a leisurely pace... knowing when you mash the gas, the monster you built will come alive.
Haha sorry for not providing much contribution to the thread. I do like that you are looking forward to driving it again. Sometimes we get so concerned with the build that we forget the joy of driving the end result. Not just competing and "the number" either. Just cruising down the open road at a leisurely pace... knowing when you mash the gas, the monster you built will come alive.
I caught your screen name on the main page (of the Gen III Internal section) as the last post and thought to myself this has the potential to be good!
And yes....I have been crunching numbers so long on this combo my head is spinning. No doubt I'm thrilled with the results but I really need to get this engine in the car. Unfortunately my story is the classic shoe maker with the worn out shoes.....but soon I will be wearing a really spiffy pair.
(Btw....when your car is down close to four years....soon is relative!!)
-Tony
02-03-2012, 08:53 AM
#173
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Excellent. Well you know what they say about cobblers... the menders of old souls [sic].... lol.
I know what you mean about downtime. I let my old Honda CRX sit for 8 years before I finally put the engine back in and got it going. I was very happy have it back on the road. Soon was not soon enough!
Let me take my turn to say thanks for all the information you provide here. I can't count how many posts of yours I have read. And, as I gather ideas to build a 427cid engine for my T/A, how many of them have shaped the direction I intend to go.
I know what you mean about downtime. I let my old Honda CRX sit for 8 years before I finally put the engine back in and got it going. I was very happy have it back on the road. Soon was not soon enough!
Let me take my turn to say thanks for all the information you provide here. I can't count how many posts of yours I have read. And, as I gather ideas to build a 427cid engine for my T/A, how many of them have shaped the direction I intend to go.
02-03-2012, 09:54 AM
#174
Same here & am sure there are several others. So much so that he's credited in my sig.
Now...Tony, get back on that beast so we can get the FEBRUARY update, lol.
02-03-2012, 02:10 PM
#175
FormerVendor
Thank You Tony for making the AFR245s readily accept 3/8ths pushrods! We just finished an engine with them and they are very nice. I think its one of the very best heads out there right now.
02-04-2012, 11:01 AM
#176
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Silly comments first:
Don't forget to weigh the manifold, between the paint and the plaster it may weigh more then a regular fast 102!
Questions:
If the extra work on the manifold pays off would you let FAST use it for a recasting (of course if they payed you that is)?
Are you going to put any decals/emblems on the Corvette to indicate its a 454 (like the old Corvette 454 fender and tail emblems)?
Do you have plans for a C6 Grand Sport /ZR1 style rear fenders for the car (to allow for a wider wheel & tire combo).
Are Suspension upgrades in the works as well?
Question not related to this engine in general, but is something I've wanted to ask:
Have your or AFR ever thought about changing the valve angle on the cathedral port heads?
How much importance is velocity -vs- volume for an intake port, and is there an optimum velocity and volume for a given engine size (displacement)? +/- cam size and intake runner length.
Don't forget to weigh the manifold, between the paint and the plaster it may weigh more then a regular fast 102!
Questions:
If the extra work on the manifold pays off would you let FAST use it for a recasting (of course if they payed you that is)?
Are you going to put any decals/emblems on the Corvette to indicate its a 454 (like the old Corvette 454 fender and tail emblems)?
Do you have plans for a C6 Grand Sport /ZR1 style rear fenders for the car (to allow for a wider wheel & tire combo).
Are Suspension upgrades in the works as well?
Question not related to this engine in general, but is something I've wanted to ask:
Have your or AFR ever thought about changing the valve angle on the cathedral port heads?
How much importance is velocity -vs- volume for an intake port, and is there an optimum velocity and volume for a given engine size (displacement)? +/- cam size and intake runner length.
02-04-2012, 03:30 PM
#177
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Sounds like a mean hook on the big end, how high were you spinning it?
