VAC 4.4L Low Comp Stroker

[squartus]

After spinning my bearings on new WPC treated OEM ones after about 27,000 miles Iv decided to do a Stroker rebuild. Going low compression to run safely with my ESS vt-2 625 supercharger, keeping stock boost/pully etc.

Purpose of the build is for a bullet proof daily driver, removal of the factory problems the engine comes with and able to safely run 7.5PSI. Not going to crank up the boost etc as im happy with the current power for my daily driver, just wanted the car to last me a LONG time.
Looking like 2 months on the build, pistions are going to take 4-6 weeks to build and coat alone.

-VAC Motorsports - 82.7mm Crankshaft
-CP - (8) Forged Pistons, with Rings Pins and Locks
-Arrow Precision - (8) H-Beam Con Rods
w/ ARP Connecting Rod Bolts
-Darton - (8) Flanged Style Cylinder Sleeves
VAC High Performance Rod Bearing Set
VAC High Performance Main Bearing Set
CP Ceramic Coating, Dome
CP Teflon Coating, Skirt
CP Piston Pin, Heavy duty
Raceware Main Stud Kit
Raceware Head Stud Kit


10:1 CR



While the stage 3 head was tempting.. I decided to stick with my guns and not worry about adding most HP I could, having my local shop do a full head refresh while VAC builds the short block.

[Grk_M3]

Bud. Sorry about your motor... im in the same boat. Do a little more research on the sleeved route... i also wanted to go sleeved, turns out motors that have been sleeved, havent proven them selves... rather go for mahle pistons and get the block bored...

[squartus]

Hear alot of conflicting things on the sleeved blocks, did alot of study on it. Seems the big thing is doing it correctly, if so suppose to have no negatives even on crazy boosted cars. When boosting an aluminum block you get distortion and the spun iron sleeves won’t distort like an aluminum block will. Also when VAC sleeve the block they leave the sleeves prone off the block few thousandths of an inch to create almost like an O-ring style seal between the bloc and the heads.

But yea looks like if want to keep this engine for life a full rebuild is pretty much it.

[SYT_Shadow]

squartus

I don't know about the sleeve rebuild. The most powerful functioning S65, Drew's, does not use sleeves. The S55 does not use sleeves either. I'm skeptical at best.

Did I read correctly that your bearings failed after changing them for WPC ones?

[8600RPM]

How will you make the same power running a much lower compression? Seems like a ton of work to use a very non aggressive supercharger setup and you'll end up with less power. Doesn't make a lot of sense to be that overly conservative on a rebuild .

[Richbot]

He was using a 4.0 before

[squartus]

Correct this is bumping it up to 4.4L 10% HP/torque alone, also get more power from boost on a larger displacment as well. All total ill get more power, and can always crank up the boost if I ever desire.
As stated above though massive power is not the point of it, yes I could crank up boost and hit well over 700hp pretty easy with this new engine. But point was to create a street stroker running boost that will last from now on. Its my daily driver, 600WHP is fine for a everyday driver atleast for me.

I will not be doing the Texas mile with this car, will not be trying to break 10s on the strip. Just a super tough high HP daily driver that can run boost without a sweat.

[squartus]

Originally Posted by SYT_Shadow

squartus

I don't know about the sleeve rebuild. The most powerful functioning S65, Drew's, does not use sleeves. The S55 does not use sleeves either. I'm skeptical at best.

Did I read correctly that your bearings failed after changing them for WPC ones?

Yes failed on WPC treated OEM bearings and ARP bolts. Far as sleeves go even Lang Racing prefers to do the strokers on sleeved blocks, all the builders iv spoken with said if price did not matter then do sleeve it. Doing it correctly is the main thing, if done right it has no drawbacks and only adds to the engine.
S55 is a different engine, has a cast iron block that can handle WAY more than the Alum s65 block can. Really no need to sleeve it at all.

[8600RPM]

S54 is iron. S55 is aluminum non sleeved f80 engine

[squartus]

Originally Posted by 8600RPM

S54 is iron. S55 is aluminum non sleeved f80 engine

Ah yes you are correct, was thinking s54. S55 is a closed deck design and also uses twin-wire arc spraying process to deposit molten iron onto the cylinder walls. Still a totally different engine/block.

Brother has a 335is but forgot it retained the s54 and didn't get the s55.

[SYT_Shadow]

Originally Posted by squartus

Yes failed on WPC treated OEM bearings and ARP bolts. Far as sleeves go even Lang Racing prefers to do the strokers on sleeved blocks, all the builders iv spoken with said if price did not matter then do sleeve it. Doing it correctly is the main thing, if done right it has no drawbacks and only adds to the engine.
S55 is a different engine, has a cast iron block that can handle WAY more than the Alum s65 block can. Really no need to sleeve it at all.

As you wish. I'm not trying to rain on your parade, just would like to understand

I'm just saying I haven't seen any sleeved engines anywhere here operating. The only high power S65 builds are done by ESS kits with an engine builder that doesn't use sleeves.

Many people love sleeves, I get that, but where are all the builds?

If I were building a LC engine to last forever, I would model it after the only engines that seem to function and then add less boost = last forever!

[CIFUM3]

Squartus please keep us posted this is the exact build I want to do for mine. Engine is still strong but I want a low compression stroker but I want to get closer to 700 than 600

[squartus]

Originally Posted by SYT_Shadow

As you wish. I'm not trying to rain on your parade, just would like to understand

I'm just saying I haven't seen any sleeved engines anywhere here operating. The only high power S65 builds are done by ESS kits with an engine builder that doesn't use sleeves.

Many people love sleeves, I get that, but where are all the builds?

If I were building a LC engine to last forever, I would model it after the only engines that seem to function and then add less boost = last forever!

Ran across quite a few sleeved boosted strokers, VAC has 2 strokers being built at the same time as mine those 2 are sleeved builds. Ginati's twin turbo stroker is sleeved as well
ESS also was happy I sleeved it "they have a no advice on engine build policy though" as they are who will be doing the tune since they have one specific for a 4.4L low compression stroker.

http://www.vacmotorsports.com/blog/a...ur-bmw-engine/


I understand your view though, I at first was against it but after really digging into the matter I was swayed over to the dark side.

[squartus]

Originally Posted by CIFUM3

Squartus please keep us posted this is the exact build I want to do for mine. Engine is still strong but I want a low compression stroker but I want to get closer to 700 than 600

Will do sir, Im requesting pics of the build process for the form as well. Any questions about the build etc let me know. Like said will take about 2 months to build the block so will be awhile sadly.

[Richbot]

This must be a busy time of year? Lots of people building motors in advance of year-end championships or something?

[squartus]

Originally Posted by Richbot

This must be a busy time of year? Lots of people building motors in advance of year-end championships or something?

Must be, I know atleast 1 of the engines was a 100 octane race engine. First thing they said when I called was how busy they are and let me know up front build was going to take awhile.
Figures my engine gives out at a busy time of year

[8600RPM]

Originally Posted by squartus

Ah yes you are correct, was thinking s54. S55 is a closed deck design and also uses twin-wire arc spraying process to deposit molten iron onto the cylinder walls. Still a totally different engine/block.

Brother has a 335is but forgot it retained the s54 and didn't get the s55.

My man you are mixing engines left and right

S54 was iron block, e46 m3 engine.

N54 was all aluminum twin turbo of the 335x

S55 is new f80

[squartus]

Originally Posted by 8600RPM

My man you are mixing engines left and right

S54 was iron block, e46 m3 engine.

N54 was all aluminum twin turbo of the 335x

S55 is new f80

Ah see what it is, brother kept talking about his iron block N54 "never paid much attention to it" Will be busting his balls about that.
N54 did come stock with Iron Sleeves though.
But yea got my N's and S's all jacked up, was only ever really intrested in the s65 engine as I came from v8's.
Love this car, but the problems its giving me is turning me Gray.

[Grk_M3]

Originally Posted by squartus

Hear alot of conflicting things on the sleeved blocks, did alot of study on it. Seems the big thing is doing it correctly, if so suppose to have no negatives even on crazy boosted cars. When boosting an aluminum block you get distortion and the spun iron sleeves won’t distort like an aluminum block will. Also when VAC sleeve the block they leave the sleeves prone off the block few thousandths of an inch to create almost like an O-ring style seal between the bloc and the heads.

But yea looks like if want to keep this engine for life a full rebuild is pretty much it.

I also know of a motor done by vac with the exact same process you stated above with the sleeve a little prone... ends up oil was leaking from the head gasket due to the thousands of an inch... that owner had to drop more cash at another engine builder, as vac doesn't warrant racing engines....

Im not trying to be negative towards vac or yourself... i just hate seeing peoples cash being wasted... (im also finishing off my rebuild)