Dinan 4.6L Dyno - Finally

[Beemdog]

Originally Posted by xaappx

Nice power gains, but for $36,000?

That's $360 per horsepower. Better than some exhaust systems...

[ilikebmxbikes]

Originally Posted by regular guy

Yes, everything on the same day except for before/after on the tuning. When uploading a flash, the ECU adaptations are typically cleared and this often causes higher readings on the dyno (giving an inflated impression to the owner about the post-tuned results). Dyno a few weeks later, and the results go back down. That's why I always recommend waiting two weeks after tuning before another dyno session to ensure the results aren't artificially influenced by clearing adaptations. And if you plan on using race gas on the dyno, for most accurate results I also recommend to run at least 1.5 tanks through the car/ECU beforehand.

At first it was believed the other Dinan guy's numbers were low because the data logs showed the throttle bodies closing early. See this DynoDB entry. So he took the car back to Dinan for retuning and a few months later dyno'd again. But it wasn't apples to apples because he went catless, added an xpipe, and stage-2 tune. He picked up 12whp, but at least the throttle bodies weren't closing too soon now. But the results were still lower than expected. See this DynoDB entry.

Why are your results so high? Currently your stroker results are tied in the Dyno Database for the highest seen on 91 octane. You can compare and see for yourself where you stand. Visit the Dyno Database, then type "4.6" into the search window. It would be interesting to see your results on the same a bay area dyno that has seen 30 other S65's.

All sounds good. I very much appreciate your input and will do as you suggest. I can take my car to the local dyno for the before and after. I dont plan on modifying anything else on the car motor or exhaust wise so we should get some clear data from it all. I am curious to see how the BPM tune could enhance the low dynoing Dinan Stroker car as well. So hopefully he can dyno his car again alongside mine.

Originally Posted by xaappx

Nice power gains, but for $36,000?

I paid $55k for the car with the stroker in it. I originally purchased it to pull the motor for my 1 series and put my 1series 4.0L in it but after driving the m3 with the stroker, I quickly realized that it is too good to pull the motor. The 1 series is 450lbs lighter than my m3 so even with the 4.0L it is very quick and can do without a stroker... for now.

[xaappx]

Originally Posted by ilikebmxbikes

I paid $55k for the car with the stroker in it. I originally purchased it to pull the motor for my 1 series and put my 1series 4.0L in it but after driving the m3 with the stroker, I quickly realized that it is too good to pull the motor. The 1 series is 450lbs lighter than my m3 so even with the 4.0L it is very quick and can do without a stroker... for now.

But curious, for the Dinan stroker, I wonder where the $36K comes from... a stroker is typically new rods, pistons, crank... why so expensive?

Don't take it the wrong way... not trying to be an ass, just honestly curious.

[ilikebmxbikes]

Originally Posted by xaappx

But curious, for the Dinan stroker, I wonder where the $36K comes from... a stroker is typically new rods, pistons, crank... why so expensive?

Don't take it the wrong way... not trying to be an ass, just honestly curious.

Basic dinan stroker is $26k. The motor is also bored out to increase the displacement from 4.0 to 4.6L. The more expensive motors like mine have new dinan ITB's. The price for what the stroker is, is reasonable. The price per HP is what is debatable vs a supercharger option.

[1MOREMOD]

Originally Posted by ilikebmxbikes

Basic dinan stroker is $26k. The motor is also bored out to increase the displacement from 4.0 to 4.6L. The more expensive motors like mine have new dinan ITB's. The price for what the stroker is, is reasonable. The price per HP is what is debatable vs a supercharger option.

Thought stroker made the displacement larger by increasing stroke?

[regular guy]

Originally Posted by 1MOREMOD

Thought stroker made the displacement larger by increasing stroke?

Bore and stroke.

[rantarM3]

Originally Posted by regular guy

Bore and stroke.

Here's a 4.4 stroker video with a dyno chart at the end. Maybe you can put this into your dyno database.

Not sure how to convert/compare the power and torque results.

[regular guy]

Originally Posted by rantarM3

Here's a 4.4 stroker video with a dyno chart at the end. Maybe you can put this into your dyno database.

Not sure how to convert/compare the power and torque results.

There's really not enough Superflow dyno results to warrant a separate category for them...and I can't mix them in with a different type of dyno. This is maybe only the third I've seen (and one of them was our own). So unfortunately they don't get in.

[rantarM3]

Originally Posted by regular guy

There's really not enough Superflow dyno results to warrant a separate category for them...and I can't mix them in with a different type of dyno. This is maybe only the third I've seen (and one of them was our own). So unfortunately they don't get in.

Do you have any idea where a 4.4 stroker would come in relative to the stock and 4.6 engines? With a 4.4 the block would not have to be bored, right?

[OM VT3]

Originally Posted by ilikebmxbikes

Basic dinan stroker is $26k. The motor is also bored out to increase the displacement from 4.0 to 4.6L. The more expensive motors like mine have new dinan ITB's. The price for what the stroker is, is reasonable. The price per HP is what is debatable vs a supercharger option.

What's the difference with the new dinan ITB's?

[ilikebmxbikes]

Originally Posted by leigh

What's the difference with the new dinan ITB's?

http://www.dinancars.com/product/d76...e90-e92-e93-2/


"Dinan® bores each of the M3's eight individual throttle bodies to a larger internal diameter, increasing air flow area by a full 8%. The larger bore improves air-flow to the combustion chamber for further increases in power, as well as more immediate throttle response."


They claim 7hp and a 5lb/ft - how accurate or measurable that it is debatable.

[regular guy]

Originally Posted by rantarM3

Do you have any idea where a 4.4 stroker would come in relative to the stock and 4.6 engines? With a 4.4 the block would not have to be bored, right?

Roughly speaking, the different displacement horsepower figures will always be proportional to their displacement differences. For example, the 4.6L stroker is 15.5% larger than stock, and when compared with identical mods, usually shows about 15% more horsepower. The 4.4L is 10% larger than stock, and I would expect about 10% more power out of it. The 4.6 is 4.6% larger than the 4.4, so you would expect about that same power gain there as well. In reality, it's usually a tiny bit less than the exact ratio.

Yes a 4.4L motor can be made without boring the block. But me personally, I never liked the idea of putting a new piston and rings inside an old bore hole. So at the very least, I'd recommend honing it to get a new surface on the bores. At the end of the day, you'll only save about $600 doing it this way. So IMO, get some slightly oversized pistons, bore, hone, and do it right.

[regular guy]

Originally Posted by ilikebmxbikes

http://www.dinancars.com/product/d76...e90-e92-e93-2/


"Dinan® bores each of the M3's eight individual throttle bodies to a larger internal diameter, increasing air flow area by a full 8%. The larger bore improves air-flow to the combustion chamber for further increases in power, as well as more immediate throttle response."


They claim 7hp and a 5lb/ft - how accurate or measurable that it is debatable.

I tested the Dinan throttle bodies on my stroker. Baseline dyno was 24-hours earlier, same dyno, same tank of gas, same weather conditions. I lost 2 horsepower. Same kind of chassis dyno Dinan uses: Dynapack.

http://www.s65dynos.com/showDyno.php?recID=382

[rantarM3]

Originally Posted by regular guy

Yes a 4.4L motor can be made without boring the block. But me personally, I never liked the idea of putting a new piston and rings inside an old bore hole. So at the very least, I'd recommend honing it to get a new surface on the bores. At the end of the day, you'll only save about $600 doing it this way. So IMO, get some slightly oversized pistons, bore, hone, and do it right.

That was my next question, actually. Instarted thinking that the bore would be worn-in for the shorter stock stroke and that just building a stroker without honing is probably not a good idea. Do you think the cost for a 4.4 build is pretty close to a 4.6?

I wish we had more information on the gts and crt 4.4 units, specificlly whether the heads and cams are the same as the stock S65.

Thanks for all then information.

[regular guy]

Originally Posted by rantarM3

That was my next question, actually. Instarted thinking that the bore would be worn-in for the shorter stock stroke and that just building a stroker without honing is probably not a good idea. Do you think the cost for a 4.4 build is pretty close to a 4.6?

I wish we had more information on the gts and crt 4.4 units, specificlly whether the heads and cams are the same as the stock S65.

Thanks for all then information.

The costs to build 4.4 and 4.6 are identical. Surely you'll wonder why everybody doesn't just build a 4.6 instead of 4.4. Well, as usual there are trade offs.

Dinan and RD Sport took two different paths to get to 4.6L, and both have trade offs. Dinan chose an 83mm stroke and 94mm bore to give you 4608 CC's. RD Sport chose an 85mm stroke and 93mm bore to give you 4619 CC's. The Dinan approach maxes the cylinder bores out to 94mm, and all but guarantees you can't rebuild the motor with an oversized piston. The RD Sport approach will give you at least two rebuilds, but the compromise is a smaller, and arguably weaker piston wrist pin. The factory wrist pin is 21mm. Dinan keeps this larger size wrist pin. The 85mm stroke requires a smaller wrist pin. I believe that's the only way they were able to keep the piston configuration at 12.0:1 compression ratio.

In reality, the smaller wrist pin is plenty strong for an NA engine. However you'll notice on all of the RD Strokers in the Dyno Database, they seem to struggle to make power above 7800 RPMs. Schrick or RD Sport mild cams will cure that problem as we saw with the Alekshop stroker dyno results. But cams are another $3k expense.

So the best compromise seems to be the 83mm stroke with 93mm bore to make a nice 4510 CC (4.5L) engine. You could destroke to 81mm x 93mm bore for 4402 CC's as well. Either of these allow you to keep the 21mm wrist pin if that's of concern and my gut tells me they won't struggle as much at 7800 RPMs as the 85mm stroke engines.

I hope this helps.

[Hujan]

Originally Posted by regular guy

The costs to build 4.4 and 4.6 are identical. Surely you'll wonder why everybody doesn't just build a 4.6 instead of 4.4. Well, as usual there are trade offs.

Dinan and RD Sport took two different paths to get to 4.6L, and both have trade offs. Dinan chose an 83mm stroke and 94mm bore to give you 4608 CC's. RD Sport chose an 85mm stroke and 93mm bore to give you 4619 CC's. The Dinan approach maxes the cylinder bores out to 94mm, and all but guarantees you can't rebuild the motor with an oversized piston. The RD Sport approach will give you at least two rebuilds, but the compromise is a smaller, and arguably weaker piston wrist pin. The factory wrist pin is 21mm. Dinan keeps this larger size wrist pin. The 85mm stroke requires a smaller wrist pin. I believe that's the only way they were able to keep the piston configuration at 12.0:1 compression ratio.

In reality, the smaller wrist pin is plenty strong for an NA engine. However you'll notice on all of the RD Strokers in the Dyno Database, they seem to struggle to make power above 7800 RPMs. Schrick or RD Sport mild cams will cure that problem as we saw with the Alekshop stroker dyno results. But cams are another $3k expense.

So the best compromise seems to be the 83mm stroke with 93mm bore to make a nice 4510 CC (4.5L) engine. You could destroke to 81mm x 93mm bore for 4402 CC's as well. Either of these allow you to keep the 21mm wrist pin if that's of concern and my gut tells me they won't struggle as much at 7800 RPMs as the 85mm stroke engines.

I hope this helps.

Interesting stuff, RG. Forgive my ignorance, but why does a longer stroke result in a smaller wrist pin? I'm not doubting you at all, but the reasons for that effect are not obvious to me.

Also, since engine work is almost certainly in my future, it would be interesting to see your recommendations/thoughts on engine work depending on different goals. For example, I've often wondered what it would take to build an S65 that could safely rev to 9,000 RPM. I assume that lighter engine components would be an important part of this puzzle (e.g., rods, valve train components), but I'm unsure what effect such a pursuit would have on bore and stroke dimensions (other than my simplistic sense that the more over-square the engine, the better it is for a high RPM performance).

[regular guy]

Originally Posted by Hujan

Interesting stuff, RG. Forgive my ignorance, but why does a longer stroke result in a smaller wrist pin? I'm not doubting you at all, but the reasons for that effect are not obvious to me.

I'm not 100% sure myself, but I know this was one of the compromises RD Sport had to make to get the 85mm stroke. Maybe one of the engine designer dudes on the forum can chime in with a definitive answer. I can describe what changes in the piston design on the various strokers, but I'm just not sure which one or more of these play the role in the smaller wrist pin.

I'm going to guess that it's most likely the only way to get the piston to clear the crank as it approaches bottom-dead-center. The piston dome design needs to be a minimum thickness, shape, and size to hit your target compression ratio. Under that the rings probably need to be specific sizes and distances from each other. Under that comes the wrist pin, and finally the piston skirt. Let's assume the design of everything from the center of the wrist-pin to the top of the piston dome is fixed in stone and can't change all that much. Likewise, you would need a minimum side skirt on the piston. So now if you increase the wrist pin diameter, you displace the side skirt because you can't displace the top of the piston. So the side skirt becomes longer and might have problems clearing the crank at bottom-dead-center. I know the pistons come pretty darn close because the design has a relief machined in them just to clear the oil squirters at bottom-dead-center. Or let me say this another way: with 21mm wrist pin, the side skirt might crash the crank. So to fix that, a smaller wrist pin would help prevent it by allowing the side skirt to be a little shorter.

I've got some other ideas why the smaller wrist pin might be needed, but this one seemed like the most likely in my mind. Maybe some of the engine design dudes can shed more light on it...that's my SWAG for what it's worth.

[Shredicus]

Hmm

4.5l makes for a nice round number...

[StealYourFace]

Dinan also offers a 4.2

http://www.dinancars.com/product/d85...-v-8-engine-2/

[e92zero]

Amazing motor, would love to build/have a stroker some day. On a separate note, the engine in the 918 spyder is a 4.6 L V8 that rev to 9k. Would love to see that with the S65. Probably still not gonna be at 600+ hp though.

[Law]

Amazing build. This surely is a dream motor.
Pity that BMW couldn't allow the S65 to develop further. Had the engineers been allowed to continue to refine and improve the platform like they did with the iron block I-6 of the S50 & S54 line, the results would have been truly spectacular.

[regular guy]

Originally Posted by regular guy

I'm not 100% sure myself, but I know this was one of the compromises RD Sport had to make to get the 85mm stroke. Maybe one of the engine designer dudes on the forum can chime in with a definitive answer. I can describe what changes in the piston design on the various strokers, but I'm just not sure which one or more of these play the role in the smaller wrist pin.

I'm going to guess that it's most likely the only way to get the piston to clear the crank as it approaches bottom-dead-center. The piston dome design needs to be a minimum thickness, shape, and size to hit your target compression ratio. Under that the rings probably need to be specific sizes and distances from each other. Under that comes the wrist pin, and finally the piston skirt. Let's assume the design of everything from the center of the wrist-pin to the top of the piston dome is fixed in stone and can't change all that much. Likewise, you would need a minimum side skirt on the piston. So now if you increase the wrist pin diameter, you displace the side skirt because you can't displace the top of the piston. So the side skirt becomes longer and might have problems clearing the crank at bottom-dead-center. I know the pistons come pretty darn close because the design has a relief machined in them just to clear the oil squirters at bottom-dead-center. Or let me say this another way: with 21mm wrist pin, the side skirt might crash the crank. So to fix that, a smaller wrist pin would help prevent it by allowing the side skirt to be a little shorter.

I've got some other ideas why the smaller wrist pin might be needed, but this one seemed like the most likely in my mind. Maybe some of the engine design dudes can shed more light on it...that's my SWAG for what it's worth.

I asked Van Dyne this question yesterday. He thought most likely there wasn't enough room for the ring pack and 21mm wrist pin to get the piston compression height where it needs to be. So the smaller wrist pin would be required. That was my #2 choice. But he also said the BDC clearance could be just as likely to need the smaller wrist pins as well.