M20 B3x Naturally Aspirated Stroker build past, present and future

[pantelones]

i've only every had mine on a eddy current dyno so you can load it up real heavy or really light.

Interesting, I didn't even realize how many different types of dynos are out there. I had to search that to understand what you meant. haha They come in both hub and roller, but that type of dyno seems to be the better option regardless of the configuration.

All the Ducati sport bikes had functional ram air and even after data logging on the track we hardly ever had AFRs far enough off to warrant a charge.

I am speaking about fuel only here, timing adjustments were left on the known conservative side.

I also don't think interia is superior in any way, just pointing out a skilled operator can do some good work on one.

All hail to the Ducati hahaha I would think that with the bikes it would be even more crucial since you spend very little time WOT and is mostly finesse. A friend of a friend was a factory Suzuki moto GP rider and had "don't do it" as a sticker covering the red-line region on his shift light/rev counter. I'll have to take a photo of that if I ever go to his house again.

And a skilled operator is just that, a skilled operator, ya know? I just thought it would be a good bit of info to know how he is testing the motor since it does make a difference and I'm sure I'm not the only one wondering...

[LJ851]

Well, how loaded was the dyno? 10% for rolling road?

I don't want to muddy up this thread too much,
Most of my experience is with motorcycles that are AphaN and a Dynojet dyno. I hardly ever loaded the dyno, sometimes drag the brakes to to slow the passing of a cell. All the Ducati sport bikes had functional ram air and even after data logging on the track we hardly ever had AFRs far enough off to warrant a charge.

I am speaking about fuel only here, timing adjustments were left on the known conservative side.

I also don't think interia is superior in any way, just pointing out a skilled operator can do some good work on one.

[digger]

i've only every had mine on a eddy current dyno so you can load it up real heavy or really light.

last full tune i had was last year with the first Alpha-n for the dbilas setup. it needed no adjustment whatsoever on the street it was brilliant straight off the bat

sometimes the very light load and throtle transinets need to be done on the street but above this it shouldnt need it unless you are getting some serious ram air

[pantelones]

It's one thing to make power, but through experience, making that power for 12+hr at a time is a different animal. Love my mates down under, still curious though.

I'm curious to see what digger or anyone else with experience has to say. This is method of tuning is not just for reliability concerns, but for scenarios on a race track where you are not operating at full throttle; for instance you have corners that you cannot be completely flat out in, if you "lift" to not hit the car in front of you, or any other scenario that is again, dynamic, and not just a flat out pull.

[ForcedFirebird]

I actually was going to add if you would chime in as well since I know that you do a lot of tuning, but you responded before I could edit my post. haha Thanks for the input!

It's one thing to make power, but through experience, making that power for 12+hr at a time is a different animal. Love my mates down under, still curious though.

[pantelones]

There is truth here. I often tune the car to behave on the street and sacrifice power for drive ability, and to be safe for a longer life span.

I actually was going to add if you would chime in as well since I know that you do a lot of tuning, but you responded before I could edit my post. haha Thanks for the input!

[ForcedFirebird]

You can do a hell of a lot of tuning in between on and off throttle on an inertia dyno.

Well, how loaded was the dyno? 10% for rolling road?

[LJ851]

You can do a hell of a lot of tuning in between on and off throttle on an inertia dyno.

[ForcedFirebird]

The g37 resonance tuning link I posted in your exhaust thread reminded me of the type of dyno being used, and I was wondering what you were testing on? Rollers, or bolted to the hubs themselves? I ask this because a friend of mine is a very good mechanic, and was the lead electrical tech for Toyoda in our area for sometime. In a conversation with a mutual friend (also very intelligent) the principles of dynamic tuning was bought up (explained to him by Roman, our mutual friend.) The typical roller dyno is not dynamic, and is really only used to lean out the tune, and the majority of the tuning is done while driving the car on the road. This is done like this because the car is not ever driven completely on, or off full throttle. The car is tuned under the circumstances in-which it is desired to be driven. On the other hand, a hub mounted dyno is in fact able to be tuned dynamically, and most, if not all of the tuning can be done on that dyno. I am just beginning to get into in-depth tuning and understating engine design to the fullest and was wondering if you could shed some light on the topic, and/or correct my understanding of what I have stated above.

There is truth here. I often tune the car to behave on the street and sacrifice power for drive ability, and to be safe for a longer life span.

[pantelones]

The g37 resonance tuning link I posted in your exhaust thread reminded me of the type of dyno being used, and I was wondering what you were testing on? Rollers, or bolted to the hubs themselves? I ask this because a friend of mine is a very good mechanic, and was the lead electrical tech for Toyoda in our area for sometime. In a conversation with a mutual friend (also very intelligent) the principles of dynamic tuning was bought up (explained to him by Roman, our mutual friend.) The typical roller dyno is not dynamic, and is really only used to lean out the tune, and the majority of the tuning is done while driving the car on the road. This is done like this because the car is not ever driven completely on, or off full throttle. The car is tuned under the circumstances in-which it is desired to be driven. On the other hand, a hub mounted dyno is in fact able to be tuned dynamically, and most, if not all of the tuning can be done on that dyno. I am just beginning to get into in-depth tuning and understating engine design to the fullest and was wondering if you could shed some light on the topic, and/or correct my understanding of what I have stated above.

[digger]

Little bit off topic, but where did you source your new throttle cable. I was trying to find one a while back, but settled for a 2nd hand one. Ended up being similar in stickiness so I just pumped some wd40 down the throttle tube which seemed to help :/

Also those are some great numbers :)

just went to the bmw dealer last year was about $100 ish

[bmwandhonda]

Little bit off topic, but where did you source your new throttle cable. I was trying to find one a while back, but settled for a 2nd hand one. Ended up being similar in stickiness so I just pumped some wd40 down the throttle tube which seemed to help :/

Also those are some great numbers :)

[digger]

Ahh I see. I pretty much figured that you were trying to eliminate the "plenum constraint" so to speak, but the way you changed the trajectory of the air rushing into some of the trumpets would be interesting to see on a dynamic model. All in all, your design looks great, but a booster-less (or electric booster) brake set up would be nice to eliminate the limiting space for a larger plenum yet. Also, why did you choose a cone filter apposed to the flat style used in the s54 CLS plenum?

I used a 4” inlet so that inlet velocity would be nearly halved assuming flow was the same. A small inlet would nozzle (aim) the flow to a certain point inside the box. hence I tried to minimize this by making it easier to convert velocity to pressure (pressure recovery) . I didn’t use a CSL style filter because of space. I think I could use panel filter if I did it again but it would not be as large as the CSL one.
It would be so easy without the booster there, if only they moved it on RHD cars…..

If I understand this correctly your basically stating that the small plenum is hurting low velocity despite the small runner size because it isn't feeding the runners enough air (at 2500RPM) to utilize the small runners to increase velocity, correct? And, the one that you have designed doesn't have that issue due to the fact that there will always be enough air in the plenum to keep the trumpets fed the air that they need to operate at an optimal efficiency?

One theory I had is that at low rpm the plenum (due to its size) was creating a slight amount of “negative boost” which caused a slight dip in the torque curve. Even the Dbilas with its big diameter manifold and plenum boosted torque in the 2600-3100rpm range (albeit by a lesser amount) and it has a larger plenum than the factory manifold.

Another theory I had was If I look at the open trumpet run this also shows signs of boosting torque at this rpm so perhaps the shorter runners 200-300mm work better in this range than very long runners 400mm+ like the OEM one. Maybe the fact that the length I am using works best at 5500-6500rpm means that at half of this engine speed it also works well?

You could probably model something in EAPro or similar and study pressure traces etc.

[pantelones]

I Played around with similar things before in solid works but you need port pressure as a function of time and pressure depends on the inlet so it is iterative. The solve time is a lot longer. I designed the airbox to be large so that it is effectively like open trumpet. If I had used a smaller volume airbox then there would be more Merit in a transient analysis.

Ahh I see. I pretty much figured that you were trying to eliminate the "plenum constraint" so to speak, but the way you changed the trajectory of the air rushing into some of the trumpets would be interesting to see on a dynamic model. All in all, your design looks great, but a booster-less (or electric booster) brake set up would be nice to eliminate the limiting space for a larger plenum yet. Also, why did you choose a cone filter apposed to the flat style used in the s54 CLS plenum?

The BMW manifold plenum has small volume and if you compare the torque curve the small plenum of the BMW appears to hurt torque at 2500rpm (even with long skinny runners) but helps at 3500rpm. Where as when I added the airbox there was no real tuning happening over the open trumpets just an overall small increase. plenum /airbox volume appears to work in a narrow rpm band where it resonates at the same frequency as the engine but you get a negative boost elsewhere

If I understand this correctly your basically stating that the small plenum is hurting low velocity despite the small runner size because it isn't feeding the runners enough air (at 2500RPM) to utilize the small runners to increase velocity, correct? And, the one that you have designed doesn't have that issue due to the fact that there will always be enough air in the plenum to keep the trumpets fed the air that they need to operate at an optimal efficiency?

[ForcedFirebird]

HP+ are nothing like these. Sending PM to keep your engine thread from getting cluttered.