Brice's NA V6 Build

Alright so I just took the truck to the store and back. I will redo a bit of my prior descriptions.

So I did a pull in first gear to 6800 or so, it revs there no problem, its super smooth doing it, even more than with stock cam timing.

I will also say 2800 rpm wasn't accurate. I was tired and it was dark so I wasn't looking carefully at the tach. I will now say it really wants to be over 3500rpm to get the feeling of "oh here's the peak power". Once over that hump it rips, or it wants to. I feel like something is off. My suspicion is the intake runners are causing something weird to happen. Over 3500 there is a increase in power but it kinda flatlines until it gets to 6000+, then it starts to feel good again? I would bet intake runners closer to the length of a 3vzfe or shorter would be a much better match to the current cam and cam timing applied here.

 

My thinking, is that the stock ECU can't really compensate in its timing map for what's going on with the cam timing, and that is part of the dead feel in the middle. But I do agree about the intake runners, they should make it feel pretty dead after about 4000-4500 I would think. I have been contemplating building a forward facing intake for the 5vz Tacoma's that is a lot like the one I made for our drag truck, but flopped over to the driver's side for clearance. Combo of a timing map overhaul and a shorter runner intake would do a lot. Plus, in a turbo situation, having a bigger turbine wheel/housing would be necessary as well

 

Looks like you made it back!

Yeah I've got a intake design in mind with 7.5" runners, also forward facing. I was thinking of having the runners angled at the valves and have them protrude into the manifold, then just increase its volume by the amount the runners occupy. In my head I would still use the stock lower manifold and for the time being use the stock throttle body.

I'm also curious to see the effects of all this stuff on a stock ECU, it's probably not doing the best a standalone could, but it's neat to see what it tolerates

 

Glad to be back

I'm digging hearing about your experimenting on the stock ECU, because it helps prove my theories and I know it will help even more having it on haltech. My intake design would use 4" long 90° runners to a flange that goes to the lower intake. Shortens the runners, and still should fit under the hood. I'm pretty stoked to try the one we have sitting here!

 

That may actually be a better size pre lower manifold. I was thinking 7.5" total and I know there's a few inches of runner past the flange of the lower manifold.

 

Well, hopefully this summer I'll be able to share the same cam combo, potentially the same cam degreeing setup, and a short runner intake on the dyno so we can see the actual powerband with numbers!

 

I've got a couple of ideas for cam timing I plan to implement on my truck. I'm not gonna say exactly what they are until I've got some stuff modelled. But I will say Suzuki has some inspiring tech that I think we may be able to leverage on our trucks.

 

So these are some rough models to get this idea out of my head and on paper (or a computer screen). There a several things I wanna change here, but the rough idea is present.

 

Alright so after about 8 hours of modelling I have this. This will be my first prototype (3d printed to verify amount of phase change and general fit relative to the part itself and the cam) I modelled it for 18* advanced with 15* advanced in mind.

this model has accurate geometry and clearance for being made of steel. Tolerances will be increased for the 3d printed part, likely to be made of PETG. Also I wont be testing the 3d printed part on the truck, that probably wouldn't end or work well.

This version lacks any oil seals which I plan to incorporate later to have it be self lubricating with some variety of oil.

The idea is that it will advance the intake cam from -7.5* to +7.5* and retard the exhaust cam from +7.5* to -7.5*. In theory I would set the intake cam 7.5* retarded relative to factory timing (one belt tooth retarded) and then somewhere near my 6800 redline (maybe 6500?) end up with the exact opposite for better top end breathing.




The splined section is directly coupled to the intake cam via a longer than factory bolt and the stock dowel pin. The outer sprocket/ramp section will be retained on the splined section with a C-clip facing away from the engine and a shoulder facing toward the engine to prevent any axial movement. The outer sprocket section will be coupled to the splined section via 13 10mm ball bearings and the phase plate (plate with the curves) held in a neutral position by a wave type spring. The spring will be retained by a big washer thing that im not 100% set on and the spring will be preloaded by the cam bolt once tightened to factory spec.

Basically at idle everything will spin as one. Once RPM increases the ball bearings will overcome the spring pressure and move outward due to the ramped nature of the sprocket/ramp plate. As they move outward they will force the phase plate clockwise a maximum of 18*, thereby advancing the intake cam and retarding the exhaust cam. The splined section of the phase plate will phase the cam and the splined shaft will allow forward axial movement for the ball bearings to migrate outwards with RPM.

I have absolutely no idea if this will work. On paper it certainly can work but I have no clue what the spring rate should be nor the ramp angle. Currently the ramp angle is 8* which should be pretty mild from what I've researched on mechanisms of this type. The spring in the model is 65lbs which may, or may not be, too much, but should be in the ballpark of the forces generated here.

Ideally I will end up with a 5VZ with mechanical VVT, perhaps the first ever, if not with VVT then certainly with purely mechanically VVT

 

And a what it looks like fully assembled as a 3d model (OEM cam gear is about 45mm thick vs this at 62mm thick currently, 17mm difference) (measured from bolt head to end of sprocket)

 

Thats a ton of really really cool modeling, how are you planning to get stuff made?

Reminds me of SxS CVT design, you should be able to refer to those spring/ramp/weight calculations to make sure you will at least have action in you working RPM range if not actually at a target RPM.

To my knowledge this type of mechanism would probably be progressive over a fairly "large" RPM range vs modern designs capable of executing a large advance at a specific RPM.

Alfa Romeo has a horrendously annoying Mechanical VVT from the... 70s that my Dad loves to tinker with, but damn those cars need an overhaul every 6k miles.

They have an imbalanced but possibly more tuneable centrifugal advance mechanism.

 

My dad has a Spider and the FI on those things is terrible.
I keep telling him to convert it to carb. Doesn't start like 3/5 times

 

Yeah the working range should be fairly large so I'll probably end up targeting a balance, but any advance done to the intake retards the exhaust since they are counter rotating. If I start with the intake retarded then the exhaust is advanced and I already know that that combo works pretty well until 3000-3500 where it literally stops the engine from revving. If I can tune it to be around 0° at 3000 then advance from there I should be in good shape I think.

As for manufacturing I am looking at places like PCBway or jlc PCB. They do cnc stuff but I haven't uploaded anything to them to check price yet.

I found that Alfa Romeo stuff in my research but honestly I glanced at the design and kinda forgot about it. I will look into it more though. As far as tuning goes I have a few options for ball bearings like tungsten, titanium and nickel and also the spring itself and if need be the phase plate as well, so I should have decent head room to tune I think.

 

Quite fascinating

 

If you have access to one, and time to do so, I'd definitely urge you to do some dyno time at the advanced, stock, and retarded cam orientations, and then have them overlaid to see where the power crosses over for each. If you are just going strictly from advanced on both to retarded on both, it would essentially just be adding timing to the early rpm and pulling timing from the top, which can be done from an aftermarket ECU or some other timing curve controller. In order to make it really beneficial, you'd want them to adjust separate from each other so you can advance the intake cam as rpm rises while leaving the exhaust neutral. The big benefit will come from having essentially more lobe separation as rpm goes up which should maintain a higher torque for longer. You might also be able to apply the idea to the helical gear that connects the two camshafts to just allow a small amount of separation there. Maybe start them 2° closer together and have them separate completely by 3500-4000rpm. Should transition from a more torque oriented separation to a more peak power separation that way

 

Well with how the exhaust is driven, retarding the intake advances the exhaust, so from the start the lsa would be pretty narrow right? Then as the intake advances that retards the exhaust widening the lsa right? The way I'm currently running it is 7.5/1.5 retarded intake/exhaust. I guess I could start 7.5/1.5 advanced but then as the intake retards the exhaust would continue to advance... I'm about to have a few days off so I plan to research more for a better understanding. This type of cam setup seems to be unique when it comes to getting good numbers for advanced/exhaust.

@Torspd know any good dyno's ?

 

Unless I'm lysdexic, if the intake cam advances, the exhaust cam advances. So the separation remains static, you just essentially create a mechanical timing retard across the powerband instead of more cam lobe separation

 

Just did a little looking, retarded intake and advanced exhaust is more overlap and advanced intake and retarded exhaust is less apparently, I guess I got it backwards

 

That would definitely be true if both cams were directly driven by the crank and spun the same direction

I could be wrong but my testing this far tells me on a slave driven cam setup whatever you do to the sprocket driven cam does the opposite to the slave driven cam. That's why when I only retarded the Intake the engine wouldn't rev past 3500, I basically aggressively set it for low rpm power. Right now my intake is retarded 7.5 degrees and my exhaust is retarded 1.5 degrees by way of moving the exhaust cam one internal gear tooth back (retarded).
Basically (+ = adv. - = ret. Sprocket tooth = 7.5°, internal gear = 9°) Intake -7.5 = exhaust +7.5 so to get -7.5/-1.5 you do intake -7.5 the exhaust is +7.5 plus -9 for -1.5

Hopefully that makes sense lol, TW should allow voice messages

Edit: Previously read exhaust