Honing possible 4F BUH 5.0? - This is our TTH850+ - 10.xxS 1/4th mile Project.

5.0 V10 50v biturbo - 571 bhp
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RS6EPE
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Honing possible 4F BUH 5.0? - This is our TTH850+ - 10.xxS 1/4th mile Project.

Post by RS6EPE » Thu Jul 08, 2021 9:43 am

Edit: The BUH 5.0L V10 has something called “ Hypereutectic aluminum” cilinders. It can be honed, but needs a different technique.

I just love this car, so heres a post in which we will track all progress and changes made. The car apparently is so populair that someone is willing, right now to spend/work towards a 1200-1400+ HP Build with a billet(!) version of this engine with charge coolers, custom manifold, precision turbos.....just wow. I hope we will hearing more from this one in 2021...

We currently finished our TTH850 project (but already looking forward to another upgrade in the future for the 1000+ HP). However for this we do require a larger piston ring gap in combination with a stronger gearbox (or even a forged build). What we have done with our currently TTE850 setup:

- PCV Check & vacuum check.
- 50 cent "O" ring replacement, also replaced back "triangle" shaped holder just to be sure.
- Replaced all rubbers, rings and such outside block
- Replaced sump pomp rummers
- Oil pump top rubber replaced (was leaking).
- Removed the carbon buildup at the intakes.
- TTE850 set with steel downpipes.

Does anyone know if this engines cylinders can be honed? (is it correct that an oversize pistons cannot be realized because of the cilinder wall type?).

I forgot to place catalysators in the exhaust line in all the excitement, so before the car can drive on the road legally here we still need to add these. Due to circumstanced this will be done 1st or 2nd quarter of 2022 together with the software. From the downpipes to the back we will be creating a custom titanium 3" line with two X pipes and custom muffler boxes, we hope that this way the sound will sound better than just stainless steel.

I could not wait and tried driving it gently in the surrounded area but even at 40%-50% throttle the car goes into limb mode because lack of proper tune. It does already feel pretty quick and I honestly think we can do a 10.xx< on the 1/4th mile under the right conditions.

Short revs with current exhaust: https://youtu.be/QOgHX8f_MzE
Cold start with current exhaust: https://youtu.be/8uMaPkZ2pQY
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Last edited by RS6EPE on Fri Jul 09, 2021 1:31 pm, edited 7 times in total.

welwynnick
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by welwynnick » Thu Jul 08, 2021 10:01 am

What a great first post, and welcome to the forum!

I love the sound, and thanks for the pictures.

Yes, you can hone the BUH engine, but not using conventional methods. I used to have a favourite link for this, but then my Windows broke, so I'll have to find it again.

Get back to you soon,

Nick

RS6EPE
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by RS6EPE » Thu Jul 08, 2021 10:12 am

welwynnick wrote:
Thu Jul 08, 2021 10:01 am
What a great first post, and welcome to the forum!

I love the sound, and thanks for the pictures.

Yes, you can hone the BUH engine, but not using conventional methods. I used to have a favourite link for this, but then my Windows broke, so I'll have to find it again.

Get back to you soon,

Nick
Cheers! I just emptied the muffler boxes and refilled them (tight) with muffler wool, and all cats and 2nd mufflers are deleted however I am not happy. I would really like to hear the V10 hum instead of the V8 rumble if that makes sense? Its near impossible to really get that hum out like a V10 Lamborghini engine however I do think we can "smooth" the rumble out with a really hard alloy such as titanium, good solid welds and a chamber like setup in the exhaust boxes like the Panamera has.

I would really like to get some more information about the wall of the cilinders. I have cleaned and revised another BUH engine (got lots of pictures if anyone want to see them) recently, but did not went inside the block because compression was sort of decent and cilinder walls looked allright (turbos failed because of PCV failure) but internals were still decent so with a new set of turbos, revision of the pump side with the dreaded O ring and the block was good to go to a new owner. I did have a complete PCV check on my TTH850 block since I know these engines require a good to perfect PCV vacuum/working order not to I*(&^@! after some millage.

c3nturi0n
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by c3nturi0n » Thu Jul 08, 2021 10:18 am

Quick question (for a novice in the world of exhausts), what benefits do you gain with the use of s/steel downpipes?
2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

RS6EPE
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by RS6EPE » Thu Jul 08, 2021 10:24 am

c3nturi0n wrote:
Thu Jul 08, 2021 10:18 am
Quick question (for a novice in the world of exhausts), what benefits do you gain with the use of s/steel downpipes?
I honestly do not know results/benefits directly as we have no comparison runs on the dyno, sound wise its allot louder and deeper - I do see that the flow could be better with the rather cheap downpipes we used. If I could re-do this job I would have gotten titanium ones made or -> (get the MORE expensive steel ones if you want to replace them, we had to heat and bend a spot as this KWE set does not fit at all. Still hear a vibrating sound when turning a sharp left because of this spot. We also welded in a bar between the exhaust just before the flexible bit to prevent rattling and vibrating around). They were filthy cheap so I am not complaining haha. They are allot more straight and some points have a larger diameter than the original downpipes. I think if the flow is better this could result in better spool up, little better responds and a slight increase in horsepower depending on turbo size.

welwynnick
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by welwynnick » Thu Jul 08, 2021 10:34 am

What size are the pies?

c3nturi0n
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by c3nturi0n » Thu Jul 08, 2021 11:19 am

nice work - thanks for heads up
2008 RS6 Avant (Monza Silver)
- Stage II MRC tune with gearbox (720PS/850Nm)
- MIJ Powerflow exhaust (non-res)
- H&R ARBs

RS6EPE
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by RS6EPE » Fri Jul 09, 2021 10:42 am

welwynnick wrote:
Thu Jul 08, 2021 10:34 am
What size are the pies?
They are 3" downpipes, and we are planning to use 3" titanium all the way to the back if this fits. (We also need to integrate 200CPI cats somewhere)

welwynnick
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Re: Honing possible 4F BUH 5.0? - TTH850+ Project.

Post by welwynnick » Wed Jul 14, 2021 8:32 am

RS6EPE wrote:
Thu Jul 08, 2021 10:12 am
welwynnick wrote:
Thu Jul 08, 2021 10:01 am
What a great first post, and welcome to the forum!
I love the sound, and thanks for the pictures.
Yes, you can hone the BUH engine, but not using conventional methods. I used to have a favourite link for this, but then my Windows broke, so I'll have to find it again.
Get back to you soon,
Nick
I would really like to get some more information about the wall of the cilinders. I have cleaned and revised another BUH engine (got lots of pictures if anyone want to see them) recently, but did not went inside the block because compression was sort of decent and cilinder walls looked allright (turbos failed because of PCV failure) but internals were still decent so with a new set of turbos, revision of the pump side with the dreaded O ring and the block was good to go to a new owner. I did have a complete PCV check on my TTH850 block since I know these engines require a good to perfect PCV vacuum/working order not to I*(&^@! after some millage.
Here are some of the links about Alusil honing that I had lost:

https://www.enginebuildermag.com/2016/0 ... um-blocks/
https://www.audizine.com/forum/showthre ... sil-Blocks
https://www.motorgeek.com/viewtopic.php ... 9&p=469482
https://www.motorgeek.com/viewtopic.php?f=10&t=37611

Nick

Caino6
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Re: Honing possible 4F BUH 5.0? - This is our TTH850+ - 10.xxS 1/4th mile Project.

Post by Caino6 » Tue Jul 20, 2021 8:17 pm

Looking forward to seeing more of this! Nice work!
Daytona Grey Audi RS6 C6
732bhp 990nm

RS6EPE
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Re: Honing possible 4F BUH 5.0? - This is our TTH850+ - 10.xxS 1/4th mile Project.

Post by RS6EPE » Tue Jul 20, 2021 10:19 pm

:rocker:
Caino6 wrote:
Tue Jul 20, 2021 8:17 pm
Looking forward to seeing more of this! Nice work!
Yes, it will be next year but most definitely will be posting updates on the titanium exhaust. Lets bring out the humm!!

Caino6
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Re: Honing possible 4F BUH 5.0? - This is our TTH850+ - 10.xxS 1/4th mile Project.

Post by Caino6 » Wed Jul 21, 2021 8:04 pm

RS6EPE wrote:
Tue Jul 20, 2021 10:19 pm
:rocker:
Caino6 wrote:
Tue Jul 20, 2021 8:17 pm
Looking forward to seeing more of this! Nice work!
Yes, it will be next year but most definitely will be posting updates on the titanium exhaust. Lets bring out the humm!!
Plenty of videos once titanium exhaust is on please!
Daytona Grey Audi RS6 C6
732bhp 990nm

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