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I'm using the smaller 100mm pulley, part number 24996-AK038.
The pistons were 8.8:1, factory CR is 10.0:1 on the DE's if I remember correctly, so it dropped it a fair amount ( I did this because I didnt plan on running race gas or E85 at all times and wanted a bit of a margin of safety there)
As for that throttle setup, its still throttle by wire from what I can tell, not throttle by cable, i'll essentially be doing the same thing, just without having to cut my hood in half to fit it. I just need to find a decent bosch or hitachi throttle and finish welding up the upper plenum and then I should be able to fit it all under the hood with a little bit of massaging.
That video looked like there was at least a bigger intake pipe, I really don't think a bigger TB will do anything without it. I welcome being wrong though.
The bend in that pipe on the video is horrible, much worse than stock. Huge waste of time. I know I pasted the science behind pressure drop via pipe diameter, number of bends and degree of bends somewhere on my350z.com.
The bend in that pipe on the video is horrible, much worse than stock. Huge waste of time. I know I pasted the science behind pressure drop via pipe diameter, number of bends and degree of bends somewhere on my350z.com.
Absolutely agree, my thinking here is the inefficiency is in the manifold not the TB. Any gains would come from a manifold change and not a TB being bigger, this it FI we are talking about. In NA a gradual taper is good which it why the TB makes gains, in FI I don't see a whole lot of people running bigger TBs, most likely cause they aren't needed.
Absolutely agree, my thinking here is the inefficiency is in the manifold not the TB. Any gains would come from a manifold change and not a TB being bigger, this it FI we are talking about. In NA a gradual taper is good which it why the TB makes gains, in FI I don't see a whole lot of people running bigger TBs, most likely cause they aren't needed.
I suppose you can consider how a larger diameter intake pipe on an n/a setup still makes more power without a manifold change. A larger t.b. will further extend gains from a larger intake pipe due to the same physics principles. The larger the pipe, the fewer and less dramatic the bends and tthe shorter the pipe the less pressure loss will be experienced. It must benefit f.i. Probably in several ways
There was some pretty thorough testing by a race team up in Canada, SG Motorsports, which then became On-Point Dyno iirc, they established that the upper intake manifold design from the factory was an extremely limiting factor. They essentially made a custom upper with a plunger in it, pulled it when the car was at WOT to see if the additional volume of air would actually allow them to make anymore power and it did.
So then they modified a stock upper with some sheet metal, and that is essentially what I copied
And then with another company they designed a custom carbon unit.
On their N/A engine I believe they picked up something like 30 or 40rwhp when going to the modified stock plenum, larger throttle, and a bit larger intake piping. Its pretty well documented, so I am hoping I can achieve somewhat similar results in my supercharged application.
Oh don't take what I'm saying the wrong way, the stock setup is crap, no denying that, reason I ditched it. NA is COMPLETELY different than FI, NA will be affected by velocity because of aspiration, FI forces air in the engine, as long as there isn't a restriction it won't care.
Maybe I'll do testing when I do the kit but I'm 99% the gains from a TB alone will be negligible, if anything gains will be made getting rid of the problem in the manifold. Without going bigger with the charge pipe, a bigger TB won't do anything for FI.
Oh don't take what I'm saying the wrong way, the stock setup is crap, no denying that, reason I ditched it. NA is COMPLETELY different than FI, NA will be affected by velocity because of aspiration, FI forces air in the engine, as long as there isn't a restriction it won't care.
Maybe I'll do testing when I do the kit but I'm 99% the gains from a TB alone will be negligible, if anything gains will be made getting rid of the problem in the manifold. Without going bigger with the charge pipe, a bigger TB won't do anything for FI.
yea without a doubt there’s some key differences, but I think that upper plenum is still a fairly decent restriction. I’m not so much worried about the TB, but if I’m fabricating a new upper plenum I might as well step up to a bit larger throttle as well.
well see, I plan on trying that all out hopefully in the next few months
yea without a doubt there’s some key differences, but I think that upper plenum is still a fairly decent restriction. I’m not so much worried about the TB, but if I’m fabricating a new upper plenum I might as well step up to a bit larger throttle as well.
well see, I plan on trying that all out hopefully in the next few months
Cool, keep us updated please. I thought about possibly having a bigger charge pipe made but it might be tight and I want to retain my strut brace. If HKS claims up to 500hp with the kit as is I don't think it's worth my time trying to modify it as that's my power goal. Only reason I want to tweak the intake is so I can spray the intercooler, the little kit gained about 30whp on the dyno with spray IIRC. I think that would be worth looking into.
I'm using the smaller 100mm pulley, part number 24996-AK038.
The pistons were 8.8:1, factory CR is 10.0:1 on the DE's if I remember correctly, so it dropped it a fair amount ( I did this because I didnt plan on running race gas or E85 at all times and wanted a bit of a margin of safety there)
As for that throttle setup, its still throttle by wire from what I can tell, not throttle by cable, i'll essentially be doing the same thing, just without having to cut my hood in half to fit it. I just need to find a decent bosch or hitachi throttle and finish welding up the upper plenum and then I should be able to fit it all under the hood with a little bit of massaging.
I definitely think you would have been fine with higher compression. Good tuning, fuel return system, and supporting mods and I'm sure you'd be good. I've seen more and more folks going 11:1 on FI and making great power on lower boost levels.
I'm pretty sure 500 at the crank is what HKS claims with supporting mods but not including higher compression, meth injection or nitrous. I think Helsinki's #'s reflect HKS's claims and AKS would be there as well with cams. 400 to the wheels or 500 at the crank is about right.
400whp is plenty fast. I stayed with my brothers GT3RS (500hp version) when we raced from a roll. Faster shifts made him pull on me slightly, but in gear pace was the same.
I'm pretty sure 500 at the crank is what HKS claims with supporting mods but not including higher compression, meth injection or nitrous. I think Helsinki's #'s reflect HKS's claims and AKS would be there as well with cams. 400 to the wheels or 500 at the crank is about right.
Sure, that makes 575 HP at the crank more or less the challenge, easy IMO if you've been paying attention to my intentions. 575hp at about 6800-7000 rpm, probably use 10:1, oversized valves, head work and cams that paired with proper tuning and intercooler spray should be easy.
I probably could make a little more power by dropping the redline to 6800 and by using a smaller 110 mm pulley. Now I'm hitting the maximum revs in the supercharger outside the maximum power area. Another option would be to improve breathing in the upper rev range with ported heads, bigger cams and plenum.
However currently my focus is in improving the cooling. I need to improve the airflow to the oil cooler and radiator so the car won't overheat at the track after a few laps. I'm also struggling with ethanol temps and will be installing a fuel cooler.
Sure, that makes 575 HP at the crank more or less the challenge, easy IMO if you've been paying attention to my intentions. 575hp at about 6800-7000 rpm, probably use 10:1, oversized valves, head work and cams that paired with proper tuning and intercooler spray should be easy.
the smallest pulley is what’s recommended as a max from HKS. Increasing the airflow within the engine will effectively lower psi which one would think allow one to increase boost but as I mentioned, going beyond the smallest pulley is probably looking for trouble. Blow the compressor and off to Japan for repairs it goes. The HKS unit is badass for several reasons but it’s not the workhorse that a vortec or similar is. You could add in some nos or add a rear mount turbo which IMO would be kinda trick but the HKS has severe limitations.
That's why I'm not trying to go with crazy revs or cams, I will remain within the kits limits as for as pulley size. Unless I'm thinking of this the wrong way, the supercharger only cares about it's speed (not how much power the engine puts out) taking that air flow into consideration it's up to the engine on how much power it will make, things like CR or displacement would change that number.
Now let's look at this number, 412 whp on lower compression and no talk about larger valves, I just can't see how higher compression, head work and spraying the intercooler can't create a 88whp, ambitious maybe but it should get close.
09-24-2020, 07:48 AM
