Just bought a S65 longblock to build my stroker

[Dave07997S]

Originally Posted by BMRLVR

The difference is that I am upfront on the completion date!

Dude...ROTFALMAO...

[0-60Motorsports]

This is going to be epic. Good luck with the build.

[Vic311]

Originally Posted by BMRLVR

The difference is that I am upfront on the completion date!

[catpat8000]

Originally Posted by Dave07997S

One thing to consider, I would take a small loss at the low end for more glory at topend as long as I ran a shorter gear. I would go to 4.10s or maybe even 4.45s in a nano second with a stroker build that spun to 9k rpm. Its all in the package of the whole driveline.

Also, does the OEM stroker in the GTS have different cams than the S65B40?

Dave

First, let me say this sounds like a really exciting project!

Lots of people keep talking about 9000 rpm and we ought to discuss that a little bit. The OP mentioned a 4.5 liter motor. I don't know what bore and stroke you are planning but if, for example, we assume a 93 mm bore (1 mm overbore) and an 8mm stroke, you'll get a 4521 cc engine, about 4.5 liters. So let's start there.

With that config, at 9000 rpm you'd be looking at an average piston speed of 4913 ft/min, which is extraordinarily high. The stock motor at redline (8250 rpm) is about 4070 ft/min. Now avg speed isn't really so interesting. What is interesting is the piston acceleration which at that stroke and 9000 rpm will be about 162,000 ft/sec^2. Again, the stock motor is about 123,000 ft/sec^2.

These numbers seem way too high for any real sort of reliable operation with regular excursions to that rpm. Way too high. With the acceleration on the pistons being 32% higher at 9000 rpm, the forces on the engine internals will be 32% higher (f=ma).

You could attempt to lighten the reciprocating mass and in fact aftermarket pistons and rods will be lighter. If my memory serves, RG's carillo rods were 487g per rod vs the stock weight of 623g per rod. New forged pistons will likely be about 50g per piston lighter than stock.

So you could conceivable reduce the mass of the pistons and rods by ~185g per cylinder (136 g/rod, 50 g/piston), which is about ~1450g overall and that's a lot. But you've increased the acceleration by 32% so you'll need to reduce mass by 32% for comparable forces on the internals. This reduction with these carillo rods and new forged pistons is about 17%, nowhere near 32%. So these parts will be taking a far higher load than the factory engine ever applied to its internals.

Will the parts be strong enough to allow operation with that long stroke to 9000 rpm? That's a big, big bet on a high dollar stroker motor. Will it allow repeated operation at that rpm? I sure wouldn't try it if it were my motor.

Using the same sort of math, I tried to figure out what stroke would allow piston speeds and accelerations at 9000 rpm similar to the stock motor at 8250 rpm. The answer is that you need to de-stroke the engine by at least 5 mm, which, with a 1mm overbore (93 mm) produces a 3.8 liter engine.

I think building a big stroker gets you displacement but it moves you a lot further away from 9000 rpm, even with high end carillo rods.

Pat

[s85e90]

Originally Posted by catpat8000

First, let me say this sounds like a really exciting project!

Lots of people keep talking about 9000 rpm and we ought to discuss that a little bit. The OP mentioned a 4.5 liter motor. I don't know what bore and stroke you are planning but if, for example, we assume a 93 mm bore (1 mm overbore) and an 8mm stroke, you'll get a 4521 cc engine, about 4.5 liters. So let's start there.

With that config, at 9000 rpm you'd be looking at an average piston speed of 4913 ft/min, which is extraordinarily high. The stock motor at redline (8250 rpm) is about 4070 ft/min. Now avg speed isn't really so interesting. What is interesting is the piston acceleration which at that stroke and 9000 rpm will be about 162,000 ft/sec^2. Again, the stock motor is about 123,000 ft/sec^2.

These numbers seem way too high for any real sort of reliable operation with regular excursions to that rpm. Way too high. With the acceleration on the pistons being 32% higher at 9000 rpm, the forces on the engine internals will be 32% higher (f=ma).

You could attempt to lighten the reciprocating mass and in fact aftermarket pistons and rods will be lighter. If my memory serves, RG's carillo rods were 487g per rod vs the stock weight of 623g per rod. New forged pistons will likely be about 50g per piston lighter than stock.

So you could conceivable reduce the mass of the pistons and rods by ~185g per cylinder (136 g/rod, 50 g/piston), which is about ~1450g overall and that's a lot. But you've increased the acceleration by 32% so you'll need to reduce mass by 32% for comparable forces on the internals. This reduction with these carillo rods and new forged pistons is about 17%, nowhere near 32%. So these parts will be taking a far higher load than the factory engine ever applied to its internals.

Will the parts be strong enough to allow operation with that long stroke to 9000 rpm? That's a big, big bet on a high dollar stroker motor. Will it allow repeated operation at that rpm? I sure wouldn't try it if it were my motor.

Using the same sort of math, I tried to figure out what stroke would allow piston speeds and accelerations at 9000 rpm similar to the stock motor at 8250 rpm. The answer is that you need to de-stroke the engine by at least 5 mm, which, with a 1mm overbore (93 mm) produces a 3.8 liter engine.

I think building a big stroker gets you displacement but it moves you a lot further away from 9000 rpm, even with high end carillo rods.

Pat

Yes. Usually a stroker wouldn't be revved as high as stock and usually not higher. Just for example though s54 piston speed = 4773 which is stock and one of the highest around

[regular guy]

Originally Posted by catpat8000

You could attempt to lighten the reciprocating mass and in fact aftermarket pistons and rods will be lighter. If my memory serves, RG's carillo rods were 487g per rod vs the stock weight of 623g per rod. New forged pistons will likely be about 50g per piston lighter than stock.

Here's what I have in my spreadsheet:

Stock rods+bolts: 621.5 g
Stock pistons: 487.0 g

Carrillo Rods+bolts: 536.5 g
Stroker pistons: 430.0 g

[swamp2]

Originally Posted by catpat8000

Lots of people keep talking about 9000 rpm and we ought to discuss that a little bit. The OP mentioned a 4.5 liter motor. I don't know what bore and stroke you are planning but if, for example, we assume a 93 mm bore (1 mm overbore) and an 8mm stroke, you'll get a 4521 cc engine, about 4.5 liters. So let's start there.

With that config, at 9000 rpm you'd be looking at an average piston speed of 4913 ft/min, which is extraordinarily high. The stock motor at redline (8250 rpm) is about 4070 ft/min. Now avg speed isn't really so interesting. What is interesting is the piston acceleration which at that stroke and 9000 rpm will be about 162,000 ft/sec^2. Again, the stock motor is about 123,000 ft/sec^2.

These numbers seem way too high for any real sort of reliable operation with regular excursions to that rpm. Way too high. With the acceleration on the pistons being 32% higher at 9000 rpm, the forces on the engine internals will be 32% higher (f=ma).

I don't think these numbers are out of reach at all. The F458 is 4.5l, 94mm bore x 81mm stroke, spins 9000 rpm and makes 562 hp. Yes this Ferrari has some fairly exotic rods and pistons but probably not radically different than what should be attainable for the S65.

I'm also sure you have a problem with some of your calculations. Peak acceleration (SI units) is simply (stroke/2)xω^2 which for the F458, very explicitly, is:

(81 mm x (.001m/1mm)/2)(9000 rev/m x 1m/60s x 2Pi rad/rev)^2 = 35975 m/s^2

Converting to feet/s^2 that is about 118,000 feet/s^2.

A 6 mm stroked S65 at 9000 should be nearly identical.

The ratio of modified to stock peak accelerations are simply:

(81.2/75.2) * (90/84)^2 = 1.24

Both the pistons referenced above or pistons+rods are 87% or 88% of the mass of the OEMs. Thus forces (mxa) are:

1.24 * .88 = 1.1 (times greater)

That is 10% more force, for which there is probably more than enough margin even with the strength of stock parts.

Now I am not saying a F458 is the most reliable long lasting engine around, but it won't sieze, throw rods, deform piston pin bores or otherwise explode beating on it at the track either.

[catpat8000]

Originally Posted by swamp2

I don't think these numbers are out of reach at all. The F458 is 4.5l, 94mm bore x 81mm stroke, spins 9000 rpm and makes 562 hp. Yes this Ferrari has some fairly exotic rods and pistons but probably not radically different than what should be attainable for the S65.

I will point out the 458 uses fairly exotic titanium connecting rods (radically different than the S65) to reach 9000 rpm and there are no equivalents for the S65, even in the aftermarket. But that's not the main point here.

Originally Posted by swamp2

I'm also sure you have a problem with some of your calculations. Peak acceleration (SI units) is simply (stroke/2)xω^2 which for the F458, very explicitly, is:

(81 mm x (.001m/1mm)/2)(9000 rev/m x 1m/60s x 2Pi rad/rev)^2 = 35975 m/s^2

Converting to feet/s^2 that is about 118,000 feet/s^2.

A 6 mm stroked S65 at 9000 should be nearly identical.

I am somewhat embarrassed to say I appear to have a typo in my spreadsheet cell formula for acceleration. Redoing it, I arrive at the same numbers you have above in your Ferrari example. But it doesn't matter anyway - while I have a formula typo, the ratio between incorrect answers is preserved and my original number of 32% increased force at 9000 rpm was correct. See below.

Originally Posted by swamp2

The ratio of modified to stock peak accelerations are simply:

(81.2/75.2) * (90/84)^2 = 1.24

Just to be pedantic, the stroke I was using to get a 4.5L engine was 83.2 mm, not 81.2. An 81.2 mm stroke with a 1 mm overbore would produce an engine of size 4.4L. Also, the stock redline I was using was 8250rpm, which is what the redline on my M3 tach displays. So the calculation would actually be

83.2/75.2 * (90/82.5)^2 = 1.32

This is, as I said in my original post, a 32% increase in force on the internals, using these numbers and assumptions.

Whether the internals can be made light enough to sustain 9000 rpm without problems is an open question. As I mentioned, Ferrari uses titanium con rods for their engine. A titanium M3 rod could probably get the weight to 340g from 487g, which is substantial. However when I looked into this exact engine project, I called a few places and determined there was no aftermarket titanium rod for the S65 though I did find a company who said they could build them for me.

Pat

[BMRLVR]

Originally Posted by catpat8000

First, let me say this sounds like a really exciting project!

Lots of people keep talking about 9000 rpm and we ought to discuss that a little bit. The OP mentioned a 4.5 liter motor. I don't know what bore and stroke you are planning but if, for example, we assume a 93 mm bore (1 mm overbore) and an 8mm stroke, you'll get a 4521 cc engine, about 4.5 liters. So let's start there.

With that config, at 9000 rpm you'd be looking at an average piston speed of 4913 ft/min, which is extraordinarily high. The stock motor at redline (8250 rpm) is about 4070 ft/min. Now avg speed isn't really so interesting. What is interesting is the piston acceleration which at that stroke and 9000 rpm will be about 162,000 ft/sec^2. Again, the stock motor is about 123,000 ft/sec^2.

These numbers seem way too high for any real sort of reliable operation with regular excursions to that rpm. Way too high. With the acceleration on the pistons being 32% higher at 9000 rpm, the forces on the engine internals will be 32% higher (f=ma).

You could attempt to lighten the reciprocating mass and in fact aftermarket pistons and rods will be lighter. If my memory serves, RG's carillo rods were 487g per rod vs the stock weight of 623g per rod. New forged pistons will likely be about 50g per piston lighter than stock.

So you could conceivable reduce the mass of the pistons and rods by ~185g per cylinder (136 g/rod, 50 g/piston), which is about ~1450g overall and that's a lot. But you've increased the acceleration by 32% so you'll need to reduce mass by 32% for comparable forces on the internals. This reduction with these carillo rods and new forged pistons is about 17%, nowhere near 32%. So these parts will be taking a far higher load than the factory engine ever applied to its internals.

Will the parts be strong enough to allow operation with that long stroke to 9000 rpm? That's a big, big bet on a high dollar stroker motor. Will it allow repeated operation at that rpm? I sure wouldn't try it if it were my motor.

Using the same sort of math, I tried to figure out what stroke would allow piston speeds and accelerations at 9000 rpm similar to the stock motor at 8250 rpm. The answer is that you need to de-stroke the engine by at least 5 mm, which, with a 1mm overbore (93 mm) produces a 3.8 liter engine.

I think building a big stroker gets you displacement but it moves you a lot further away from 9000 rpm, even with high end carillo rods.

Pat

I worked out my bore and stroke to give me 4499cc which is an OEM BMW like number (S65B40 = 3999cc, S65B44 = 4399cc, S85B50 = 4999cc). If someone wants to take the time to do the math they can otherwise I will keep my actual dimensions to my self.

Anyway, as for redline, I intend to rev the engine to about 8600RPM at the highest, if I wanted to rev to 9000RPM I would not have added any stroke at all. I am quite sure the internals will be strong enough to take 9000RPM but I doubt even the Schrick 284's will be enough to keep making power with the stroker at that RPM. Once the engine is together and tuned I will set redline based on what the torque and power curves look like. No sense to rev high just for the sake of revving high....... I want the engine to be making power right up to redline.

[Someone?]

Start building in 2015?! Forget that! get to building is thing, Today! I mean with how builds work on this forum saying your going to start in 2015 is the same thing as saying it will be done by 2017!
This is Bull Crap!

[catpat8000]

Originally Posted by BMRLVR

I worked out my bore and stroke to give me 4499cc which is an OEM BMW like number (S65B40 = 3999cc, S65B44 = 4399cc, S85B50 = 4999cc). If someone wants to take the time to do the math they can otherwise I will keep my actual dimensions to my self.

Anyway, as for redline, I intend to rev the engine to about 8600RPM at the highest, if I wanted to rev to 9000RPM I would not have added any stroke at all. I am quite sure the internals will be strong enough to take 9000RPM but I doubt even the Schrick 284's will be enough to keep making power with the stroker at that RPM. Once the engine is together and tuned I will set redline based on what the torque and power curves look like. No sense to rev high just for the sake of revving high....... I want the engine to be making power right up to redline.

All makes good sense. 4499 looks to be 94mmx81mm, if I don't have another typo.

Given the displacement increase and the increased rpm, how did you select the 284 cams over other options, like the 292? According to Schrick, you can go as high as 292 before you need to worry about vanos causing piston to valve timing danger.

The big problem I found with choosing new cams on the S65 is there does not seem to be much public information on the effects, although RG and I both looked at the 284s in a very rough way here:
http://www.m3post.com/forums/showthr...5#post15384895

If you are looking for 550 crank hp, which is 32% more than stock, you're going to need to be a little bit extreme. 4.5L will get you 13% more torque. For 550 hp, you'll need to make that additional torque as far up in the rpm range as possible. Indeed, your power peak will need at 8500rpm or even higher, which seems unlikely without more significant cam timing than you are planning, given the added displacement, don't you think?

Also, RG won't your buddy have some numbers soon on his cammed stroker? He was using the 284s I think.

Pat

[BMRLVR]

Originally Posted by ibmike

Start building in 2015?! Forget that! get to building is thing, Today! I mean with how builds work on this forum saying your going to start in 2015 is the same thing as saying it will be done by 2017!
This is Bull Crap!

You work out the logistics of getting the engine from Toronto to me. Then get the engine cleared customs and down to California in a hurry without costing me big shipping and duty costs and I'll start right away! I have to coordinate this build around my work schedule and incur minimal costs

I will be going to Toronto to pick up the engine in June or July while I am on vacation. Around the beginning of 2015 I will take a little time off and will bring the engine to California coordinated with a trip to California with my wife......... There is more to life than the just the car!

[BMRLVR]

Originally Posted by catpat8000

All makes good sense. 4499 looks to be 94mmx81mm, if I don't have another typo.

Given the displacement increase and the increased rpm, how did you select the 284 cams over other options, like the 292? According to Schrick, you can go as high as 292 before you need to worry about vanos causing piston to valve timing danger.

The big problem I found with choosing new cams on the S65 is there does not seem to be much public information on the effects, although RG and I both looked at the 284s in a very rough way here:
http://www.m3post.com/forums/showthr...5#post15384895" rel="" target="_blank">http://<a href="http://www.m3post.co...st15384895</a>" rel="" target="_blank">http://<a href="http://<a href="http...384895</a></a>" rel="" target="_blank">http://<a href="http://<a href="http...95</a></a></a>

If you are looking for 550 crank hp, which is 32% more than stock, you're going to need to be a little bit extreme. 4.5L will get you 13% more torque. For 550 hp, you'll need to make that additional torque as far up in the rpm range as possible. Indeed, your power peak will need at 8500rpm or even higher, which seems unlikely without more significant cam timing than you are planning, given the added displacement, don't you think?

Also, RG won't your buddy have some numbers soon on his cammed stroker? He was using the 284s I think.

Pat

I don't necessarily care if I make 550HP but it would be nice! Let's see what the final tally will be when it is done....... No one knows what effect the cams will have on the torque curve as the engine approaches redline.

I expect this combination will make at least as much power as a Dinan or RD Sport stroker with a slight disadvantage in peak torque but with more torque approaching redline.

Time will tell.

[regular guy]

Originally Posted by catpat8000

Also, RG won't your buddy have some numbers soon on his cammed stroker? He was using the 284s I think.

Pat

Projecting end of May for final tuning and dyno results. The car will be at Bimmerfest.

BTW, I posted the correct rod and piston weights a few posts ago. Not sure if it will change your calculations or not.

[Richbot]

Swamp:

Biggest difference between the 458 motor and the S65 in terms of specific output potential in my mind is that the 458's is a DI motor. No matter how light you make the spinny/bouncy bits to rev the S65 to the moon you're still going to have trouble getting all the way to that engine's level on pump gas without the benefit of DI.

Better benchmark is probably the port-injected 430 Scuderia, plus 0.2l of displacement. That was a circa 500bhp 4.3l engine with a power peak at 8500 rpm. Sounds about like what this will be. Exotic grocery getters indeed!

[swamp2]

Originally Posted by Richbot

Swamp:

Biggest difference between the 458 motor and the S65 in terms of specific output potential in my mind is that the 458's is a DI motor. No matter how light you make the spinny/bouncy bits to rev the S65 to the moon you're still going to have trouble getting all the way to that engine's level on pump gas without the benefit of DI.

Better benchmark is probably the port-injected 430 Scuderia, plus 0.2l of displacement. That was a circa 500bhp 4.3l engine with a power peak at 8500 rpm. Sounds about like what this will be. Exotic grocery getters indeed!

Good points. I've posted (and debated) extensively on the benefits of DI, specifically that is does improve volumetric efficiency and thus provides more power (everything else equal). That slipped my mind for a bit when focusing so much on the "spinny/bouncy" bits (good term!). So yes the 125 hp/l of the 458 is probably not going to happen.

[regular guy]

I like "spinny/bouncy bits" too. Good term!

[Checkcaptain]

I have a spare GTS Engine stocked, that would have brought you close to 4.5l😉

[HapaM3]

I've always wanted to apply this to mechanics because it's found everywhere in nature. What if you applied the Fibonacci sequence to the block internals? Forget BMWs patterns...

[catpat8000]

Originally Posted by HapaM3

I've always wanted to apply this to mechanics because it's found everywhere in nature. What if you applied the Fibonacci sequence to the block internals? Forget BMWs patterns...

Well, let's see. There is:

1 engine block
1 alternator
2 exhaust headers
3 inch stroke
5 it is derived from a 5 liter V10
8 connecting rods
13 was the last year of production
21 ahhh... I give up.

Pat

[coloradoe92m3]

21 mpg on freeway

[regular guy]

Originally Posted by catpat8000

Well, let's see. There is:

1 engine block
1 alternator
2 exhaust headers
3 inch stroke
5 it is derived from a 5 liter V10
8 connecting rods
13 was the last year of production
21 ahhh... I give up.

Pat

Awesome!

Originally Posted by coloradoe92m3

21 mpg on freeway

Perfect!