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Progress on my insane VQ35HR 240Z project


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further progress with the plenums. The design has taper for maintaining air velocity and volume uniformity, it has horns internally to optimize flow, and long runners for midrange torque. Otherwise, it's guesswork until we get dyno proof. If nothing else, it's a turbo motor so flow inefficiencies will be masked by FI and it'll look cool :wink:

 

The plenum will taper to meet the throttle body at the front.

 

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7308414476_0e1be34b8c_b.jpg

 

mark

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Nice, that sounds awesome. Thanks for the link. it's pretty cool, I guess the screens help keep the air out of the pump and reservoir. Yours looks really nice. Did you have to supply much for the HR engine, for them to make you one, or perhaps they already had the HR specs. Eitherway, it sounds like an awesome setup. A pump that size should really move a lot of oil. I love the shiney billet alum.

 

The two images I linked show the GTR intake, I read up a bit, I guess GTM is almost done with their VQ35 adapter for that intake. I'm really starting to consider getting one. I guess Greddy has their own version of it for the VQ35 as well which is supposed to flow better. It's interesting. who knows if it really makes that much difference. Though, for your intake, are you concerned at all about how well it flows compared to stock? though with the turbos you're putting in it might be a moot point.

 

I assume your CPS still on the flywheel, or you'd need a custom wheel on your pully at the front of the engine.

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early drawing of my diffuser and exhaust setup. This is generally how I first try and resolve packaging issues. In this instance, I'm trying to create a setup where the exhaust can be switched to free flow or quiet mode and where the diffuser runs under the rear suspension arms and works elegantly with the original body lines. I'm planning on making it with CF (duh) by creating a reverse mold in foam, smoothing it, and then laying CF.

 

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Edited by markrolston@mac.com
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That should be awesome. Which area will you be mounting the diffuser to? Will you have to cut areas out for the suspension to move and flex? Have you selected a muffler type yet? From the drawing, the muffler looks like it will fit behind the fuel cell.

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That should be awesome. Which area will you be mounting the diffuser to? Will you have to cut areas out for the suspension to move and flex? Have you selected a muffler type yet? From the drawing, the muffler looks like it will fit behind the fuel cell.

 

the suspension travel should still work without cutouts. The diffuser will mount to a crossmember in the front and to the body in the rear. We are looking for a muffler but given the shape and the 2-in, one-out, all on one side of the muffler, we'll likely just make our own.

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further progress with the plenums. The design has taper for maintaining air velocity and volume uniformity, it has horns internally to optimize flow, and long runners for midrange torque. Otherwise, it's guesswork until we get dyno proof. If nothing else, it's a turbo motor so flow inefficiencies will be masked by FI and it'll look cool :wink:

 

The plenum will taper to meet the throttle body at the front.

 

7308415632_d9ff704240_b.jpg

7308415086_9131ae9428_b.jpg

7308414476_0e1be34b8c_b.jpg

 

mark

Mark,

 

FWIW, taper and maintaining air velocity are used for wet intake runners (carburation or PFI) in order to keep the fuel atomized. You may be better off having a larger, straight runner with a tapered air horn at the end. It all depends on how you're injecting the fuel, but any way you look at it, higher air velocity and decreasing runner diameter equals more pumping losses. I've made some detailed posts about intake design, if you're interested: http://forums.hybridz.org/index.php/topic/105783-ideal-intake-runner-taper/

Edited by Leon
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Mark,

 

FWIW, taper and maintaining air velocity are used for wet intake runners (carburation or PFI) in order to keep the fuel atomized. You may be better off having a larger, straight runner with a tapered air horn at the end. It all depends on how you're injecting the fuel, but any way you look at it, higher air velocity and decreasing runner diameter equals more pumping losses. I've made some detailed posts about intake design, if you're interested: http://forums.hybridz.org/index.php/topic/105783-ideal-intake-runner-taper/

Thanks. So looking at what I'm creating, do you have particular suggestions? The fuel rail is in the stock location, towards the base of the runners. Air horns are inside the plenum for each runner. Tb's are stock.

 

Mark

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Thanks. So looking at what I'm creating, do you have particular suggestions? The fuel rail is in the stock location, towards the base of the runners. Air horns are inside the plenum for each runner. Tb's are stock.

 

Mark

Mark,

 

It comes down to what you're looking for. My suggestion would be to use straight runners up to the air horn, with the diameter matched to the intake port. Make the runners as straight as possible. I haven't done design work with multi-runner plenums, so can't help much there.

 

Air horns are not trivial, especially if you're making your own intake. Air horn geometry has a noticeable effect on powerband, with a longer (less-tapered) air horn having a weaker effect but spread over a larger RPM band, and a shorter (larger taper) air horn having a stronger resonance effect but over a smaller RPM range.

 

Where you put the horn also matters. The powerband shifts to higher rpm as the horn is placed closer to the intake valve.

 

What this means is that if you really want to optimize your setup, you'll have to do some trial-and-error. Calculations will get you close, but nothing is conclusive without actual testing. If you want to test different lengths and horn placements, you could either build a few iterations of intakes or an adjustable-length intake. For an adjustable-length intake, it can be something like having the runner that is bolted to the head house a removable joint which lets you slip-on different lengths of intake pipes with different combos of air horns. Not sure if you want to go through all the effort, just a thought in case you do.

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Mark,

 

It comes down to what you're looking for. My suggestion would be to use straight runners up to the air horn, with the diameter matched to the intake port. Make the runners as straight as possible. I haven't done design work with multi-runner plenums, so can't help much there.

 

Air horns are not trivial, especially if you're making your own intake. Air horn geometry has a noticeable effect on powerband, with a longer (less-tapered) air horn having a weaker effect but spread over a larger RPM band, and a shorter (larger taper) air horn having a stronger resonance effect but over a smaller RPM range.

 

Where you put the horn also matters. The powerband shifts to higher rpm as the horn is placed closer to the intake valve.

 

What this means is that if you really want to optimize your setup, you'll have to do some trial-and-error. Calculations will get you close, but nothing is conclusive without actual testing. If you want to test different lengths and horn placements, you could either build a few iterations of intakes or an adjustable-length intake. For an adjustable-length intake, it can be something like having the runner that is bolted to the head house a removable joint which lets you slip-on different lengths of intake pipes with different combos of air horns. Not sure if you want to go through all the effort, just a thought in case you do.

thanks. design constraints (hood) require I curve the runners in order to lay the plenums down on their sides. Horns will be mounted ~1/2" off the backing plate in the plenum. You can see the horn itself in some of the pics sitting free. Likely to switch to CF for the plenum since aluminum is turning out a PITA to shape the way I want it. Lastly, since this is estimated to be ~700hp turbocharged motor when done, the +/-5hp variable from minor design flaws isn't my concern. I'm just trying to trap major issues while at the same time keeping it an attractive design.

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thanks. design constraints (hood) require I curve the runners in order to lay the plenums down on their sides. Horns will be mounted ~1/2" off the backing plate in the plenum. You can see the horn itself in some of the pics sitting free. Likely to switch to CF for the plenum since aluminum is turning out a PITA to shape the way I want it. Lastly, since this is estimated to be ~700hp turbocharged motor when done, the +/-5hp variable from minor design flaws isn't my concern. I'm just trying to trap major issues while at the same time keeping it an attractive design.

Okay, I understand. However, air horn placement/intake length/design has an effect at least a magnitude greater than 5hp at that power level.

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I noticed you are in Austin. I moved here a couple months ago. Where are you located? Id love to come by and drool over your work some day.

The car is at a friends shop- Laivins Race Cars. I'm sure he'd be happy to show it to you if I'm not there. Just give him a heads up. I'm in/out of there during the week at odd hours so it's hard to say exactly when you'd run into me.

 

http://www.laivins.com/contact.html

 

I keep my RBZ at home. I live in the downtown area- clarksville.

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Hmm pretty cool, really looks like it' would be a pain... Probably could have 3d printed that.. Well in slices anyway. Not certain how ABS would stand up. I've been using it to make some fittings. This is what I use. The steel integration might be more difficult too. Did you check out the link I put up in my last post about the other guy making an intake?

 

Phar

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Hey Mark, I was looking at how to model an intake, and This is what I came up with. Of course it would take a bit more tweaking.

 

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post-4150-063584600 1340320543_thumb.jpg

 

I was using the PTC Creo Elements (FREE VERSION!) to make the model. I spent maybe an hour kludging this one together. here's the files as it stands:

Intake design.zip

 

You may not be interrested in going this way especially because printing something like this would have some challenges due to the size. (Mainly having to slice and glue.) Though a lot could be done on the design side internally and it would hardly look like it wasn't a single piece since tolerences would be tight.

 

Phar

Edited by Pharaohabq
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i think it will work well.

 

here is the one i made for the shop race car. (vq30det(t) has mad torque and does not fall off up top. sure it tapers of, but still keeps making power. almost 400rwkw with 2560rs turbos.

its made from 1.75" tube flared to 2" on the plenum side with internal trumpets and stock vg30 throttle bodies.

dscf9532_000.jpg

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Hmm pretty cool, really looks like it' would be a pain... Probably could have 3d printed that.. Well in slices anyway. Not certain how ABS would stand up. I've been using it to make some fittings. This is what I use. The steel integration might be more difficult too. Did you check out the link I put up in my last post about the other guy making an intake?

 

Phar

yes thanks but both his method and the final product aren't really what I'm looking for. But thanks for the help.

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