my m60b40 has higher compression numbers then factory new, after compression test?

[E32Juggernaut]

hello gents, so i did the first compression check on my 740i since ive had it, and i was quite surprised!

#1- 215 psi #5- 230 psi I though there was a mistake since the numbers were coming in linear, but i did it twice and all the same on each cylinder.
#2- 215 psi #6- 230 psi 224k on the dash so there is no way its a 93 nikasil block. New compression rating for this engine is 210 psi, so my lowest cylinder is even higher
#3- 220 psi #7- 235 psi then a standard factory built m60b40. This car has to have a modified engine in it, maybe decked heads/block, or maybe the block is a m62b44 block
#4- 220 psi #8- 235 psi which would explain the higher compression and how strong the car is. It is abnormally quick for what it is. Previous few owners used it as a drift car, but did not beat on it mercilessly has it had ample power

What do yall think?

I've done many of these test before on automobiles and aircraft recip engines. i did standard procedure and nothing to skew results. engine hot, all plugs removed, ignition and fuel disabled, no excess oil or carbon apparent in cylinders, strong battery, professional compression tester, throttle valve left closed cause i made my own manual idle air system(gets all the air it needs at idle).

[XAlt]

Maybe carbon or a bad reading, I don't doubt a Nikasil block could've held compression on 90's premium fuel.

The 62 usually reads around 180-200.

[E32Juggernaut]

Maybe carbon or a bad reading, I don't doubt a Nikasil block could've held compression on 90's premium fuel.

The 62 usually reads around 180-200.

Negative, i used a bore scope camera and its not heavy caked with carbon on any of the pistons. can still see the cross hatching marks on the walls from when it was honed. also i put cylinder 7 and 8(since they read the highest) at top dead center and scrapped at the piston with a screw driver through the spark plug hole, build up was minimal at best.
Since i wasnt believing it after the test like you, i let it cool down and did another test 6 hours later after it warmed up. All the same as before. So dont tell me i have a dirty engine. If it was carbon or oil then i wouldnt have made the post. also the last two owners and i have used nothing but shell 93 octane covering 112k miles.

[e30luv318i]

This will help tell you what block you have. My casing was on pass side

http://www.bmw7resource.co.uk/forum/...ic=4421.0;wap2

i seriously doubt you have a b44 / b40 hybrid .. does your car have a duplex chain ? If it does not it's a b44

[E32Juggernaut]

This will help tell you what block you have. My casing was on pass side

http://www.bmw7resource.co.uk/forum/...ic=4421.0;wap2

i seriously doubt you have a b44 / b40 hybrid .. does your car have a duplex chain ? If it does not it's a b44

thank you sir, ill go look for the casting number

[e30luv318i]

I remember watching your vid and your car walked on your brothers e38 m sport... that's rather impressive, perhaps there is some sort of modification voodoo at work. The m sport is not a slow car

[E32Juggernaut]

I remember watching your vid and your car walked on your brothers e38 m sport... that's rather impressive, perhaps there is some sort of modification voodoo at work. The m sport is not a slow car

i still havent checked my block casting number yet but its double row timing chain. Thanks dude. It is underestimated by everyone in my area, needless to say, the juggernaut has a lot of kills
some turbo 240sx's, e39 m-sport, 390hp trailblazer SS, 2005-2010 mustang gt's 4.6l 3 valve and so on. 0nly car its lost to in years is a 2012 mustang gt 5.0l, those come with 425hp... but i only lost by 3-4 car lengths from 40-120

[e30luv318i]

You have some nice roads in your area when I was there. RI is like a war zone of pot holes... so high speed runs are rare around here hahaha !!!

It kinda seems like there is something going on with that engine Preformance wise . My brother has a e39 540/6 and I'm dead even with him . But that's before I had my 3.15 .. how hard did you pull on the e39 ? You have a 3.15 lsd from what I remember right ? My car history was motor replacement under the campaign in 1999. So I have about 100k on my replacement, I'd consider it a healthy motor so it certainly sounds like yours is faster than mine

[E32Juggernaut]

I dont know if mine is faster then yours, maybe. but thanks! oh i avoid pot holes like the plague, we are fortunate to have more up keep.
There is some performance mojo going on ill admit. Now i have modified stock headers with the inner metal wall removed(inner wall restricts collector to about 2" give or take), dudmd tune and 404 dme, custom built heat wrapped 4" cold air intake, dual 2.5" exhaust, de-catted, and really good maintenance/cleaning. A lot of people dont realize when their pcv system goes bad and then the engine starts ingesting oil solids and vapors. over 100k miles of that mess and it builds up pretty bad on the runners of the intake manifold and cylinder head reducing port size. I kid you not, when i took off my intake manifold, i was stunned at how much gunky build up there was. The solids that stuck in the runners became like tar and thick enough to reduce port diameter and cause turbulence. I measured it before cleaning and the port diameter of all runners were reduced by 1/8 inch! thats a lot! needless to say, after cleaning it was stronger then ever and breathed much better. I didnt even know my pcv system was bad, so i guarantee most m60 owners out there are losing power due to this build up, and possibly m62 owners as well. Im pretty sure thats why my engine has great compression still, upper cylinders got all the lubrication needed from the ingested oil. Also the weak spot of 7 series cars is first gear launch, trying to get a heavy car moving quickly with a 2.93 diff ratio is alot to ask. But with a proper launch these cars become much faster, let the tires break lose and get the engine in its power band. losing traction gets a 7 series moving a lot faster then it trying to overcome its own inertia and rpms starting at 1800 rpm as it struggles.

[Jormotors]

You have some nice roads in your area when I was there. RI is like a war zone of pot holes... so high speed runs are rare around here hahaha !!

It kinda seems like there is something going on with that engine Preformance wise . My brother has a e39 540/6 and I'm dead even with him . But that's before I had my 3.15 .. how hard did you pull on the e39 ? You have a 3.15 lsd from what I remember right ? My car history was motor replacement under the campaign in 1999. So I have about 100k on my replacement, I'd consider it a healthy motor so it certainly sounds like yours is faster than mine

I think you're referring to me?? Or this is a strange coincidence, I had that video of my car against my brothers e38 and I have the 3.15 lsd as well as many other things done. I think what's really going on here is that the e32 740i is just quicker than people expect. Which to me makes sense because the 740i is so similar to the 540i, a little weight reduction and you're practically the same car. All three of us have similar experiences so I'd say this mans car is quite normal, modified e32s are great.

I'm almost finished with my 6 speed swap and will give you guys an update once it's ready!!

[htrdbmr]

Those compression numbers to me would indicate non-stock cams, (which in a BMW is unlikely) or possibly the cams were advanced (retarded?) to increase static pressures. Decking the block/heads to get an increase like you are seeing would be a very heavy cut. I vote for a non-stock block or heads.