B6 S4 V8 motor build ideas

[pfeifstudd]

I have been searching around to see if anyone has pulled this motor and built it. So my question is if you were going to keep it naturally aspirated what modifications would you make while you had the motor out. Forged internals, bore/stroke, increase/decrease compression, etc. I come from the world of mustangs and I had a B6 A4 now I have a B6 S4 but according to Audi of Chandler I have blown the motor. So I can either buy a new one from Audi, have them rebuild it or potentially send it to a local racing shop to have it built.

I am just not familiar with what people can do with these V8's if they were to really build a stout motor. I would appreciate any and all ideas.

[beemercer]

I'd give JHM a call and see what kind of price forged rods and pistons would run you. They've built at least one motor so far, if not more, and based off their other parts the quality would be the best you could get.

The forged internals are going to be better suited to a nitrous/turbo build, but...

If you are staying N/A I would advise:

-Get stock compression pistons, 11.5;1
-Get the forged rods and pistons, crank is all ready forged
-While the motor is out have the heads ported (to get the heads off you need to remove the chains on the back of the motor). The exhaust side is rather restrictive from some accounts, a proper port job could yield gobs of power. Have the porter weld in the combustion chamber a bit for higher compression (12.5:1). Possibly get schrick cams, new valvetrain pieces (valves/springs), Ferrera makes some iirc.
-Get supporting N/A parts, JHM modded intake manifold, JHM Longtube Headers, 2.5" X-pipe catback, JHM LW crank pulley, JHM Stg4 clutch and LWFW, JHM SS and shifter linkage, Stern Motor Mounts
-Get maintence stuff; oil, diff fluid, gearbox fluid, new coilpacks, new sparkplugs, K&N air filter, serp belt/tensioner/idler. Definitely get new camshaft adjusters and new timing chains/tensioners

As far as bore/stroke I would leave it where it's at. The motor is already tight with 5.5mm cylinder walls and limited valve-piston clearance. An overbore and some sleeves could work, but no one has done either.

It'd be a ton of cash for a good bump in performance, but it may be a better option to build the motor and then get JHM's twin turbo setup once its available.

[hercfe]

knife edged crank, .020 overbore, hypereutectic pistons, forged rods, 11.5-12:1 compression. ported heads, cams and valvetrain capable of 9000 rpm. dry sump oil system, stand alone EMS. Should make around 550-600 on 93 pump with meth, or E85 would be even better. assuming money is no option though, as this would cost close to 15000.

[pattrick02]

knife edged crank, .020 overbore, hypereutectic pistons, forged rods, 11.5-12:1 compression. ported heads, cams and valvetrain capable of 9000 rpm. dry sump oil system, stand alone EMS. Should make around 550-600 on 93 pump with meth, or E85 would be even better. assuming money is no option though, as this would cost close to 15000.

that sounds sick! too bad i have never heard of anyone doing such...too much money involved that's for sure! but i love the idea of having a 9000 rpm s4....that would be amazing!! i can't even imagine that.....and how would you switch to dry sump?? we need more people to start building these motors...they have potential, but too much money is involved!

[drew]

too much money and a small install base relatively speaking...

[halik]

You do realize it's an alusil block, right? It's not like you can just bore it out and that's it.

[C-losS4]

you can bore it if you install sleeves but if your not planning on making 900/1000 hp why would you, block is strong enough for 600 even 700 so b mercer is right if money is not a factor but for a tipical guy like me a ribuilt motor w forged rods would be sufficient and all the bolt on goodies, im not too sure if i would put the nos but a s/c or turbo w meth would be a more enticing power adder i know most this guys dont like s/c cars cause of heat soak but w meth injection they are a good power adder. i personally like turbos better but who knows how they will perform on this cars and they maybe over kill for a stock motor. but its all possible if you have the money.

[JimmyBones]

You do realize it's an alusil block, right? It's not like you can just bore it out and that's it.

Exactly what I was thinking. Sleeving the block would not be worth it unless money was not object.

I would get forged rods, do the head work: port and polish, oversized valves if possible, valve springs, and cams if possible; along with all the supporting stuff listed by beemercer except for the exhaust because I would want to do that myself.

[JohnnyAlQaeda]

bigger valves would be an issue as there is already barely enough room for the 5 that are there. any kind of displacement increase is really not going to be feasible, theres not a whole lot of room between cylinders plus the aforementioned alusil complications and the stroke is already pretty big. any longer and spinning it to 7k is going to give you problems. being that theres only one company out there with an aftermarket cam itd be nice to play with the rocker ratio a little bit if at all possible.
itd be nice if we could get lightweight forged components made. id kill to have a featherweight crank and slugs to go with some valvetrain work. hell lightening any of that shit up would help. a little titanium here and there never hurt anything but the wallet. as far as the 550hp out of spinning it to 9000? i highly doubt it. i think it be pushing it at 450-500ish to the wheels. i built a destroked 400 smallblock that spun to 8700 and it was only putting out around 680 or so with about 2L more displacement.

[beemercer]

Here's some pictures to elaborate:

bigger valves would be an issue as there is already barely enough room for the 5 that are there.

The intake valves (3) are very close as is. Oversized by 1mm may have them a bit too close for comfort.

any kind of displacement increase is really not going to be feasible, theres not a whole lot of room between cylinders plus the aforementioned alusil complications and the stroke is already pretty big.

Here you can see the limited space to overbore. Even with sleeving there's not a lot to work with.

any longer and spinning it to 7k is going to give you problems. being that theres only one company out there with an aftermarket cam itd be nice to play with the rocker ratio a little bit if at all possible.

For stroke we have two concerns, excessive piston speed, and valve-piston clearance. There are already recesses in the stock pistons to clear up more room for the intake valves, a longer crank is going to place the piston higher up towards the valves.. bit of valve float (which occurs at ~6.8k RPM) and now you're out a valve. The piston speed is more a longevity concern. The rods are plenty tensile strong and should be able to handle some additional stretch... but how well will the cylinder walls hold up?

[jfunkey]

to bore out the block and put in sleves is not going to be a route we should look into if you ask me. There already is coolant flow room issues and to be honiest boring out the block isn't going to give enough pwoer to make it worth the work. To stroke it good luck once again with that. No need the piston speed is already very high.

Call JHM get some rods pistons and then you can go what ever route you wish. There looks to be more power in the heads any way. No room for valves. We have a solid base right now. You can upgrade the rotoratiuonal assembly to true forged and then go twin turbo or a strong shot of nitrous

[whartung]

Now with all this talk of sleeving, are people talking about sleeving it to the same exact displacement/bore&stroke, and using a non aluminum sleeve to make up for the thin, aluminum walls? or are we talking about sleeving it narrower so the displacement is decreased, wall thicknesses increased, and boost is more feasible?

[pattrick02]

true, not too much space for oversized valves..i personally wouldn't touch that, or boring the cylinders...i think forged rods, pistons, cams and head work should be plenty good...then slap on some turbos or a s/z, and meth...or a strong shot of nitrous

[jfunkey]

Now with all this talk of sleeving, are people talking about sleeving it to the same exact displacement/bore&stroke, and using a non aluminum sleeve to make up for the thin, aluminum walls? or are we talking about sleeving it narrower so the displacement is decreased, wall thicknesses increased, and boost is more feasible?

good question. regardless of if its to the same dememtions. my thoughts. Wait till the block shows to be an issue. 3L 2.7T 600+whp motors have the same wall thickness.

we are stock with good mods n/a going 12.7 @ 111 heads who knows how much more is there. I say keep it simple go too far out with the builds and you reallty don't leaern too much and possible spend lots of money on things you don't need

[pattrick02]

good question. regardless of if its to the same dememtions. my thoughts. Wait till the block shows to be an issue. 3L 2.7T 600+whp motors have the same wall thickness.

we are stock with good mods n/a going 12.7 @ 111 heads who knows how much more is there. I say keep it simple go too far out with the builds and you reallty don't leaern too much and possible spend lots of money on things you don't need

amen. better to take it step by step, see what kind of gains you get from each mod, where the weaknesses and strengths are, and work slowly from there...which is exactly what JHM has been doing for all this time!

[AndyGs4]

The only advantage to steel sleeves is you could use a more aggressive oil control ring which may reduce the number of engines with scored cylinders.

High piston speeds, soft metals, and oil control become very touchy subjects when discussing a true high RPM build.

Forged internals are a must for strength.

LW valvetrain using titanium valve retainers, stiffer springs, ect. are a must to reduce/eliminate valve float up to 9-10K RPM or so. It would be nice if the RPM in which valve float sets in is way beyond the usable RPM of the rest of the system. There are other aspects of the valvetrain that could be addressed for weight/precision. Schrick cams are an idea; but I don't believe they make cams for this motor. They make cams for an AEB (I think) that have to be modified to run in this motor.

I like the idea of sleeves for reasons already mentioned. Not because of cylinder wall strength, but for more aggressive ring attributes.

The crank is OK, however it would be nice if there was an aftermarket crank available that was lighter, and allows the motor to be internally balanced. That way a cheap LW pulley could be used out front, and it would not need an offset weight. By placing the counterweight inside the block with the rest of the crank assembly may also reduce overall vibration in the motor. This may also be a requirement to get to 9K RPMs.

Porting the heads, yes most definitely.

[RBSileighty]

I say keep it simple go too far out with the builds and you reallty don't leaern too much and possible spend lots of money on things you don't need

Agreed... no need throwing parts at something if you don't know it needs it...

Regardless of what you do with the motor... make sure you have someone who can tune it for you (and budget that in the build as well) if you can't tune it yourself... just a side note

[Leeber]

you guys are talking about some serious dough! but i would love to see someone with the cash put this all together and bring the b6/b7 platform into the league.

[tatarin]

i like this conversation !

[jfunkey]

you guys are talking about some serious dough! but i would love to see someone with the cash put this all together and bring the b6/b7 platform into the league.

I think a few people already have. So its a wait and see.

[pattrick02]

I think a few people already have. So its a wait and see.

if they have they should show themselves! I have yet to see an all out built b6/7 s4

[Mr. Corey]

if they have they should show themselves! I have yet to see an all out built b6/7 s4

If you build it they will come

[AndyGs4]

In the next year or so, I plan (kinda depends on if my car costs me anymore damn money this year) on getting a used long block, rebuilding, getting a JHM short build (forged), and having the heads tweaked beyond comprehension. I would love to sleeve it, but that may/may not happen depending on what is available when I get the block to that point and how much it will cost.

Likely start an engine build thread on EA. Fingers crossed.

[JohnnyAlQaeda]

why is everyone so damn hooked on sleeving?!?!?! its a waste of time and money. like has already been mentioned the vast 3.0L blocks in the B5's have the same cylinder wall thickness and we all know how much power they handle...even if you stay with an N/A build and rev the piss out of it the existing rod/stroke ratio is great as far as cylinder wall wear is concerned so there is no reason for the added cost and complexity of sleeving the damn thing.

[CHECKERED]

I would appreciate any and all ideas.

100 shot of NO2 and call it a day.

[ieatfishburitos]

I would appreciate any and all ideas.

I'd start here - Lots of mod friendly V8's: http://www.summitracing.com/search/D...?Ns=Price|Desc

[0000 V8]

I for one am getting the JHM twin turbo setup sometime after it comes out. Anyone think that that setup will be able to run the FI exhaust they sell? Im already trying to get my car ready with stuff that i will be able to use in the mean time, AND after the kit goes on.

But I intend to do a full build while the motor is out for the turbo install :D

[whartung]

I for one am getting the JHM twin turbo setup sometime after it comes out. Anyone think that that setup will be able to run the FI exhaust they sell? Im already trying to get my car ready with stuff that i will be able to use in the mean time, AND after the kit goes on.

But I intend to do a full build while the motor is out for the turbo install :D

you'll probably be fine with the catback... this should be a no-brainer, but dont bother with the downpipes...



also, our cylinder wall thickness is what again? is there enough clearance to squeeze a .125 sleeve in each of the cylinders?

[Shomegrown]

why is everyone so damn hooked on sleeving?!?!?! its a waste of time and money. like has already been mentioned the vast 3.0L blocks in the B5's have the same cylinder wall thickness and we all know how much power they handle...even if you stay with an N/A build and rev the piss out of it the existing rod/stroke ratio is great as far as cylinder wall wear is concerned so there is no reason for the added cost and complexity of sleeving the damn thing.

You can't really compare the engines. One is cast iron and one is aluminum alloy.

Regular high alloy aluminum has a tensile strength of roughly 80 MPa. The AlSi17Cu4Mg mix Audi uses is at around 280 MPa. Cast irons can be up to 550 MPa and won't fatigue over time.

Bottom line, if you're going to benchmark other engines, use something similar.

[beemercer]

I for one am getting the JHM twin turbo setup sometime after it comes out. Anyone think that that setup will be able to run the FI exhaust they sell? Im already trying to get my car ready with stuff that i will be able to use in the mean time, AND after the kit goes on.

But I intend to do a full build while the motor is out for the turbo install :D

The catback should mate up no problem, the downpipes off the turbos are most likely going to be a bit different than current style downpipes (they should be shorter).

[J. Daniel]

also, our cylinder wall thickness is what again? is there enough clearance to squeeze a .125 sleeve in each of the cylinders?

There is 5.5 mm between cylinder bores. .125" is ~3mm so no. If you felt you really needed to have a steel or cast iron cylinder surface then you'd need to go with a very thin sleeve wall thickness. .030" -.040"
There's no way to get any significant displacement increase with this engine so you'd only be sleeving it for the material properties.