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RYU's "properly molested" NSX build thread
- Thread starter RYU
- Start date
Here is how they ended up. I think the black trumpets look pretty wicked. The main issue here was fitment of an airbox while also allowing for a large elliptical shaped bellmouth. Lots of compromises required on the rear bank. I didn't want to custom build a new RSTB. Needed to fit the largest, correct shaped bellmouth as possible. Needed to make room for the OEM fuel rails. Be able to close the OEM clamshell cover and so on... the 5 deg tilt on the engine and it being positioned so far back and to the right of the engine bay really makes fitment tricky with all things considered. I think this might work though. I even have the option to turn the front bank trumpets 180 deg and point them all to the front. This will allow me to center the airbox better in the engine bay... so thru the glass it will look symmetrically better. Honda never designed the engine to be viewable so I get it... Even the offset engine in the 1st gen R8 is something I cannot unsee. The dyno will tell me what the optimum trumpet size and placement will be.
Just waiting on parts..................! Have a tentative track day planned in mid Dec.
p.s. don't mind the messy engine bay.
Just waiting on parts..................! Have a tentative track day planned in mid Dec.
p.s. don't mind the messy engine bay.
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Why not have the TBs at the same angle as the intake tract? (Or closer to the same). That would get the trumpets away from the rstb and improve airflow.
Very nice work, I commend you and look forward to our next track day.
That is a great question [MENTION=16531]stuntman[/MENTION] and was heavily considered. A few things here which as part of an OEM dev team you might appreciate... (I eluded to most of them in a prior post as well) One of the design criteria was to explore a flat plane mounting point for all 6 ITBs. This would make it easier for other vendors to build an airbox. It's about a 5-8* tilt IIRC but it's all a compromise when you consider, like you said, the ITB should be perpendicular to the valve when possible for best performance, but we wanted it also fit under the factory clamshell (with airbox), and allow for the usage of the factory OEM Fuel rails and a few other things like linkage sweep operation, etc. I might be willing to sacrifice a small bit of performance for near OEM packaging and drivability, but not much!! We will see at the next dyno session. I'll make some decisions at that point. I can still modify the manifolds to orient the ITBs in the traditional way pointing each other. Hey, btw... i'm planning a track day at Buttonwillow Dec 18 in case you've really got nothing to do that day
This is pending I get the parts in time from [MENTION=20830]A.S. Motorsport[/MENTION]. I'm also exploring having a 3D printing farm print out the ASA or ABS trumpets as well as the upcoming airbox. Printing that stuff makes my entire house stink pretty bad and the garage is too cold it seems. Also don't want to put it in an enclosure because I haven't found one I trust not to be a fire hazard. I'm iffy on PETG but I think that's my only choice now if i'm printing at home.A few observations on having the trumpets point towards each other. While my butt dyno isn't that good, my hearing noticed a significant change in resonance at the high RPM. My rear view mirror started vibrating at a specific higher frequency that did not occur with the straight up 90mm spun trumpets.
i now have them pointed forward just to try...
Adnan reminded me of the similarities with the F355
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If you had The mesh on your engine cover (NSX-R style), What clearence, from trumpets to mesh, would you have [MENTION=20915]RYU[/MENTION]?
Looking at it in pictures I would say no... but do you think it would be possible to fit the airbox it under the OEM NSX-R engine cover?
Thnaks
Looking at it in pictures I would say no... but do you think it would be possible to fit the airbox it under the OEM NSX-R engine cover?
Thnaks
That is possible but it would depend on your desired trumpet length. When on the dyno I plan to run at least 3 trumpets. Short, Curved, and the 90mm Long ones. In my mind, the power curve will help us determine the airbox design.
I like the way Spoon did the FK8 airbox here. I think we can design one for the NSX that can use the factory box filter or something bigger. I don't want something overwhelming like most racecar setups.
(skip to 5:12)
https://youtu.be/a1z01eNUTwc?t=512
Even the CSL airbox is wicked looking but not sure if it's too much. A good friend of mine is helping to design this. He's actually a designer for an OEM we're all familiar with but I don't want to call him out because not sure how his employer will feel about this. In any case, I think it will turn out mature and tasteful and i'm willing to lose a small amount of performance if it means it sounds nice, fits well, and looks OEM Motorsport.
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Why are you hesitant on PETG? I print it all the time now, it's my go-to. I'm printing as i'm typing.
The M3 airbox isn't too big. You want as large of an airbox as you can get in a car with ITBs.
The M3 airbox isn't too big. You want as large of an airbox as you can get in a car with ITBs.
I don't know many using PETG in the engine bay. I know people have been successful with ASA since it's UV resistant. At this point... i'll probably end up trying PETG despite it's lower melting point than ASA.
In terms of the airbox... like I was saying before... if a larger box only nets me say... 5-10hp more.. i'm willing to loose that power if the box can be that much smaller.
We'll have to see... this is all guess work at the moment.
I just got back from a quick drive. Both trumpets are pointing forward. That high pitched resonance is gone. That's so interesting...
INSPIRED!!! :biggrin: Just ran across this thread... Great info & videos ...Got so many questions to ask you *LOL*, but first things first. Still getting everything together for my ITB set up. Thanks Regan!!!
Happy to help where I can!
That's great to know!!! i'm going to order some PETG now. You've convinced me haha... Got any recs on filament manufacturer?
i might buy some here. This company is owned by Michael Cao... he was one of the designers for the NC1 back when he was in with Honda. https://ic3dprinters.com/ I'm going to support one of our own!
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As you know, a filament's performance is greatly affected by multiple variables: print speed, print temp, feed rate, retraction, etc...
For MY printer, the MatterHackers PRO series PETG has been by far the easiest to print and strongest. I tried their "Build" series, and its surprisingly more brittle and weaker than the PRO series despite changing various settings. The Overture PETG on Amazon is only ~$20 and had with a few tweaks, prints almost as good as the MH Pro, and is close to the same strength - far stronger than the Build series.
I might suggest the PRO series because its the easiest to get right, but also the most expensive. Once you get dialed in to that PETG, it will be far easier to get Overture to work right. I tried Overture first and couldn't get it to work. Then I went PRO, was happy, and then bounced back and forth between Build and Overture and now I just use Overture. I also tried Duramic PETG and it's also not as strong as Overture, but prints great, but I wouldn't choose it over Overture. If I wanted a marginally nicer and stronger print, I would go back to PRO, but it just seemed like 255*C was a happy spot for Overture and Build, where Pro would print down in the 220-230*C range. -That's my experience on my printer. But now that i'm dialed in, I don't think i'll ever print out of PLA.
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I really like how Kakimoto designed their airbox. It's quite tidy and looks like it fits under the engine cover. Not a fan of the welded aluminum tubing and blue adapters, but you could make a FRP or CF tube that would look much more OEM and mate to the OEM airbox with a bellows.
You get a good look at the design at about 2:30 in the video below.
You get a good look at the design at about 2:30 in the video below.
100% agree the Kakimoto looks excellent. I have only 2 concerns with this enclosure
- volume is quite small
- velocity stacks have a rather poor shape and also small
This is a race car that lives primarily near redline so I reckon these "issues" is easy to ignore, but for a street car, i'm just not so sure yet. I'm hoping the dyno and a bunch more testing will help me determine a good compromise. There won't be a 1 size fits all but as with the theme of this project, I hope to find some kind of acceptable middle ground
It's really cool to see the support for ITBs for our platform. I have to say.. the throttle response between my prior CTSC setup and this ITB prototype is totally noticeable. Blips, rev-matching, etc.. has been intoxicating. Makes me want to find excuses to drive the car... even to the grocery store
Here is some inspiration for a Monday morning
- volume is quite small
- velocity stacks have a rather poor shape and also small
This is a race car that lives primarily near redline so I reckon these "issues" is easy to ignore, but for a street car, i'm just not so sure yet. I'm hoping the dyno and a bunch more testing will help me determine a good compromise. There won't be a 1 size fits all but as with the theme of this project, I hope to find some kind of acceptable middle ground
It's really cool to see the support for ITBs for our platform. I have to say.. the throttle response between my prior CTSC setup and this ITB prototype is totally noticeable. Blips, rev-matching, etc.. has been intoxicating. Makes me want to find excuses to drive the car... even to the grocery store
Here is some inspiration for a Monday morning
Regan that airbox is gorgeous! Looks OEM.
Great to see the ITBs coming together. I’m eagerly awaiting this for my own build.
Sent from my iPhone using Tapatalk Pro
Sent from my iPhone using Tapatalk Pro
100% agree the Kakimoto looks excellent. I have only 2 concerns with this enclosure
- volume is quite small
- velocity stacks have a rather poor shape and also small
This is a race car that lives primarily near redline so I reckon these "issues" is easy to ignore, but for a street car, i'm just not so sure yet. I'm hoping the dyno and a bunch more testing will help me determine a good compromise. There won't be a 1 size fits all but as with the theme of this project, I hope to find some kind of acceptable middle ground
It's really cool to see the support for ITBs for our platform. I have to say.. the throttle response between my prior CTSC setup and this ITB prototype is totally noticeable. Blips, rev-matching, etc.. has been intoxicating. Makes me want to find excuses to drive the car... even to the grocery store
Here is some inspiration for a Monday morning
Is this airbox available for my set up?? Seriously interested (& needed):biggrin:
It looks like I might be on target for a shakedown track day this coming Friday. I'm excited. This car hasn't been on track since NSXPO San Francisco. That's a REALLY long time for me.
I got a lot of the revised parts in hand and installed. ASM helped me by ordering new softer throttle springs from Jenvey. I went softer to mimic the OEM feel of the throttle pedal. The original springs they had were too stiff and a lot of force was required from your right foot. I found a happy medium by changing 4 soft and 2 regular. Again, a lot of fine tuning in this setup. I also revised all the pushrods length and the locations, height, throw angle, etc of the throttle linkages. If you saw a pic of the setup a month ago it'll probably look exactly the same but so much thought and measuring went into raising this, shorterning that, just to get the pulleys/bellcranks system to work smoothly and at the right tension and arc. It now feels pretty smooth with that rifle shotgun feel. The revised main throttle pulley linkage assembly is now a longer throw but added progressivity to compensate. The longer, quicker throw, does initiate a tiny bit of jerk from 0% TPS say at like 3k rpm. I could slow down the throttle pull with added progressivity in the pulley, but poor Adnan has suffered enough at my crazy requests! haha! What I did instead was retarded ign timing by 10 deg right at the start of the throttle press. So for a brief instant as you're pressing on the throttle she ramps up with a slightly retarded ignition. It seems to have fixed the jerk quite a bit. It rolls on pretty smoothly even when jabbing at the throttle on/off while in a turn. Super cool how the HKS ECU can provision for that! I could see this feature really saving the drivetrain in high HP applications.
I'm pretty stoked because I finally got that crisp, yet stable throttle response. Honestly, the throttle response is insanely good. I can't wait until a higher compression and overall lighter rotating assembly from my upcoming wannabe race engine. Though, I reckon i'm pretty happy with the ITBs on the stock motor for a while. hmmm...
Easier to show than to explain... Here's a quick blip sequence off idle. I got it to idle smoothly at ~850rpm btw. She blips eagerly and returns to idle w/o drama. It took some ECU tuning to get there.
https://youtu.be/jDb2TgbIepA
The ITBs also sync balance pretty well.
https://youtu.be/WrqtOrrYvn4
Already working on the airbox.
This picture is getting old, but i'm now printing new trumpets in PETG per [MENTION=16531]stuntman[/MENTION]'s suggestion. I'm eager to see if it'll hold up to track abuse.
The last of the new PETG velocity stacks almost done... by "almost" i mean several more hours lol
I got a lot of the revised parts in hand and installed. ASM helped me by ordering new softer throttle springs from Jenvey. I went softer to mimic the OEM feel of the throttle pedal. The original springs they had were too stiff and a lot of force was required from your right foot. I found a happy medium by changing 4 soft and 2 regular. Again, a lot of fine tuning in this setup. I also revised all the pushrods length and the locations, height, throw angle, etc of the throttle linkages. If you saw a pic of the setup a month ago it'll probably look exactly the same but so much thought and measuring went into raising this, shorterning that, just to get the pulleys/bellcranks system to work smoothly and at the right tension and arc. It now feels pretty smooth with that rifle shotgun feel. The revised main throttle pulley linkage assembly is now a longer throw but added progressivity to compensate. The longer, quicker throw, does initiate a tiny bit of jerk from 0% TPS say at like 3k rpm. I could slow down the throttle pull with added progressivity in the pulley, but poor Adnan has suffered enough at my crazy requests! haha! What I did instead was retarded ign timing by 10 deg right at the start of the throttle press. So for a brief instant as you're pressing on the throttle she ramps up with a slightly retarded ignition. It seems to have fixed the jerk quite a bit. It rolls on pretty smoothly even when jabbing at the throttle on/off while in a turn. Super cool how the HKS ECU can provision for that! I could see this feature really saving the drivetrain in high HP applications.
I'm pretty stoked because I finally got that crisp, yet stable throttle response. Honestly, the throttle response is insanely good. I can't wait until a higher compression and overall lighter rotating assembly from my upcoming wannabe race engine. Though, I reckon i'm pretty happy with the ITBs on the stock motor for a while. hmmm...
Easier to show than to explain... Here's a quick blip sequence off idle. I got it to idle smoothly at ~850rpm btw. She blips eagerly and returns to idle w/o drama. It took some ECU tuning to get there.
https://youtu.be/jDb2TgbIepA
The ITBs also sync balance pretty well.
https://youtu.be/WrqtOrrYvn4
Already working on the airbox.
This picture is getting old, but i'm now printing new trumpets in PETG per [MENTION=16531]stuntman[/MENTION]'s suggestion. I'm eager to see if it'll hold up to track abuse.
The last of the new PETG velocity stacks almost done... by "almost" i mean several more hours lol
Wow still kicking and refining! How do you like it vs the CTSC?
Sent from my iPhone using Tapatalk
Sent from my iPhone using Tapatalk
