Audi A4R4 450HP CBEA (CR) Build

Rub87

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So not all CR engines are 16.5:1 CR?

we have now in exeo etc, you really notice the low CR when starting without glowing in subzero temps =)
 

TDIMeister

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I guess the jumped the gun a bit. The Bin 5-spec TDI already has a CR of 16.5:1. Can't speak about other 4-/5-cylinder common-rail TDIs.
 

TDIMeister

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From another thread, this is 87turboquattro's own work, albeit on an 8V. Very nice! :) Bill, are these OE seat rings? If not, can you share the material, if known?
 

mrchill

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Those are not oe...though they are not beryllium based either. I forgot the material. Thats one of my cylinder heads. Prior to cutting of course. If you look into the ports of the CBEA you will see that the casting flash is directly related to the injector boss. If you look into the top of the head, you will see how the boss tapers and where it ends. Larger valves require larger seats for the most effect. I dont feel as yet that there is enough material for a long lasting design if you add larger seats. Part of the porting issue is removing some of this "safety material". Time will tell. I inspected the head prior to any machine work and discussed with Bill immediately why I felt o\s valves would be a challenge, without even knowing if that was in the cards. I'm always looking at options when I see anything. We will see. I cant afford one of these right now as they are 4k for a low mile one complete. Maybe later.
 

TDIMeister

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Thanks for the explanation, Chris, much appreciated. I think I have a better idea now. I'm still very much a visual person and can better understand something holding it in my hands or seeing a picture than for something to be articulated in words. I should have a chance to meet with tdisyncro in the near future to see the progress of the project.
 

87turboquattro

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TDIMeister said:


From another thread, this is 87turboquattro's own work, albeit on an 8V. Very nice! :) Bill, are these OE seat rings? If not, can you share the material, if known?
i'll have to check on material,the seats are semi custom.don't quote me but they may be a -2n material.soft to work w/ but then work harden w/ heat.work well in offshore racing.

btw,pics were set to syncro just a couple of minutes ago.:D
 

87turboquattro

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mrchill said:
Thats one of my cylinder heads. Prior to cutting of course. .
bad news chris,that was my 1z head.it was fully ported prior to this upgrade.:D

maybe a teaser pic of it now that its finished and sitting for a long rest.:D
 

mrchill

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No...you ported it more afterward...dont you remember? And where is my AHU head?:eek:
 

mrchill

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I think I'm going over to assist the one handed machinist....there may be hope yet!! We'll get pix...argue over methods....and figure out how the heck to pull off the big seats....IF he isnt preoccupied with chix and boats that is!:eek:
 

devonutopia

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Very interesting prospect, but even though I will never get close to that, I am going to see how far I can reasonably go with just 8 valves and 1 cam. :p
 

TDIsyncro

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dvst8r said:
I am curious as to your custom injectors.
I know of someone that has machined vw injector bodies to accept cummins nozzles, and has quite a wild set of custom injectors. It also sounds like (haven't actually talked to anyone) that nicktane can have a a pretty big set made.
Then there is also the route of going to someone like a DDP, or a JL Machine, or ect... and you could have new nozzles EDMed, then flowed and balanced via Extrude Hone.
Just kinda curious as to the direction you took, more then the specific size of the nozzles you had made.
The injector nozzles will be custom EDM'd and flowed. That is about all I can tell you on that front right now. There are a number of vendor options for that, and I will list them in the vendor section when we get that part in motion.
 

TDIMeister

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Now do something insane like that for Louis' 16V. It's his thread, after all. ;)
 

TDIsyncro

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shortysclimbin said:
On the piston side of things find yourself some pistons from an Audi TT CR with engine Code CBBBB The CR ratio is already 16.5:1 on those. This should allow you to cut your valve relief pockets bigger for your cam and be done with it.

Have fun with her, its always fun to build things from scratch.
I hope it will be fun, but there seems to be no shortage of challanges right now.:)
The CBEA is 16.5:1 stock. I have not looked at what CR I will end up with based just on material removal for valve reliefs. On the 8V's, it was around .25 to .5 CR. On the 16V, its hard to say because there is more valve are, but the squish area is fairly small compared to a 8V piston. Until we have the cam grind figured, which comes after the flow bench numbers from my head, which is unfinshed for 3 more months now... Its a bit of a pickle that I have to wait out. I suspect I will still have to do a bit of CR reduction to meet our goals. We have done a variety of simulations and peak cylinder pressure (PCP) simply gets to high without serious consideration to CR.
 

TDIMeister

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shadowmaker said:
40/35,5, 13mm lift. :)
This is one of those instances I regret not having a "This post is worthless without pics" graphic handy. ;)
 

mrchill

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Those sizes are really big...will require a much larger bore for sure. Still not sure that size will benefit any more than valves 1.5-2mm smaller.
 

shadowmaker

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mrchill said:
Still not sure that size will benefit any more than valves 1.5-2mm smaller.
Already had that (38/33,5 = +2/+2). 81mm bore helps with even bigger valves.

Later I will publish flow data from:
- grind only (original valves)
- +2/+2 valves
- +4/+4 valves (relocated and shaped)

MarkoP has flow data out of the original 2.5TDI head. I never measured mine as stock.
 

TDIMeister

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mrchill said:
Those sizes are really big...will require a much larger bore for sure. Still not sure that size will benefit any more than valves 1.5-2mm smaller.
The cylinder will act as a shroud for sure in those areas that come close to the valve, but the added cross-section helps everywhere else. It's a question of whether what's lost from the shrouding effect can be made back from gains in overall flow from the enlarged cross-section. Which is why in a flow bench it is vital to use a cylinder mock-up of the same diameter as in reality.

The largest diameter pistons would be nice in this regard; too bad 83 mm pistons would only leave 5 mm material between cylinders. In a gasser, this is no problem. A bit more questionable in a Diesel.
 

87turboquattro

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TDIMeister said:
The cylinder will act as a shroud for sure in those areas that come close to the valve, but the added cross-section helps everywhere else. It's a question of whether what's lost from the shrouding effect can be made back from gains in overall flow from the enlarged cross-section. Which is why in a flow bench it is vital to use a cylinder mock-up of the same diameter as in reality.

The largest diameter pistons would be nice in this regard; too bad 83 mm pistons would only leave 5 mm material between cylinders. In a gasser, this is no problem. A bit more questionable in a Diesel.
yup,chevy saw it back in the late 60's and 70's w/ the 454's and larger valves.thats why we bore notch the block to just above the ring land.i evn on certain applications do the 502's 4.47" bore.
this bore notching(i do intake and exhaust side) is good for 25-30hp on a na engine.
thats why i like using as run bores for the flow bench.and even then its only to see if i didn't screw a head up w/ an ingenious idea.:D
 

Scott_DeWitt

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What's the probability of those seats falling out when things get nice and hot?

Are they simply pressed in or are the seats supercooled and the heat superheated prior to install?
 

mrchill

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They are shrunk in. They shouldnt fall out, though its not impossible. Its a typical interference fit.
 

Rub87

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normally seats are cooled a bit and head is placed in washing machine so it's a bit warm and then they're pressed in and cut afterwards.. mine are still hanging in after more than 10.000 hard km's :D

 

TDIsyncro

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Bill and myself had a great conversation yesterday about the situation with the head. Currently the completion of the head is one of my biggest hold-ups so I was tossing around ideas as to how to keep things moving forward despite not having the head here. Bill will not be able to do porting for atleast 10 more weeks. However, he does have the ability to use his mind and his vast knowledge on valve train set-ups, and can manage to tinker with lighter stuff.

We have three big unknowns right now:
1. flow bench numbers for cam design
2. valve, spring and retainer selection that will work with the cam follower set-up and head layout. (meeting design seat pressure and lift force)
3. max allowable valve lift from new spring set-up.

Bill has concluded that he will be able to advance and resolve these issues over the next couple weeks and he seems pretty pumped about it..and so am I!:D

With this part progressed, Dave will be able to design the cam profiles, the cams can be ground. As soon as my new rods are here, I will be able to do mock assembly to check piston protrusion, select head gasket. With the cam design in hand, the piston valve reliefs can be cut based on a mathamatical model rather than trial and error.

Overall, this new direction should keep things moving in the right direction.:cool: I have sum pics to post..some now some later tonight. Bill is patiently wating for me to post the recent head porting pics.
 

Farfromovin

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Syncro- you don't happen to be some sort of logistical manager by trade do you? With all this stuff swirling around, I think I'd go crazy... Lot's of planning. Keep up the great work!
 

TDIsyncro

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CBEA Piston Comparison

This pic shows the difference between a PD piston (a BHW in this case) and the CBEA one.

BHW is on Left Side/CBEA is on Right Side




The PD piston follows the older Omega-Mulde style combustion bowl shape. The CBEA follows the latest in combustion bowl technology; Serienstand style combustion bowl.

http://forums.tdiclub.com/showpost.php?p=2619472&postcount=1

This style is more shallow and much wider. You can se how much larger in diameter the CBEA piston bowl is in comparison to the PD piston. The squish band around the top of the piston is fairly narrow.

The Common Rail piston w/rings is 606g, with a CR of 16.5:1, the BHW piston is w/rings 620g, with a CR of18.5:1
 
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