Old fashioned N/A power making... Anyone?

[arghx7]

Originally Posted by s0sl0w

Taking care of the fundamentals will only make a f/i'd motor that much better. F/I isn't a replacement for a proper internal work.

Ok, assume for discussion's sake that the FA20 can stand up to whatever cylinder pressure you throw at it as long as it doesn't experience heavy knock or preignition. That is, durability isn't an issue. And furthermore let's assume your engine is set up appropriately for E85, since it's basically race gas and that's what everyone around here likes.

Well what do you do then for n/a power? Headers are already out there, and we've figure out the appropriate lengths to reduce the torque dip (to my pleasant surprise). Well then what do you do?

So what does that leave you? Higher compression? Once you get much higher than 12.5-13:1, the piston crown gets so high in the combustion chamber that it causes mixture formation issues. Mazda did an in-depth study on it and found 13:1 to be the max for an n/a DI SkyActiv engine.

More lift and duration on the cams? Well let's say you don't have any valve collision issues. That's going to hurt your low and mid range torque. Change the valve timing? You can already do that. You can dial in however much overlap you want, and set relatively early or late closing of each valve. And ITB's? With electronic throttle, you need a way to control them--that won't be cheap.

Look at all the high-end n/a BMW engines from the past 10 years (which were admittedly PFI). They had ITB's, continuously variable valve lift, cam phasers, continously variable intake runner lengths. That stuff can only take you so far.

Originally Posted by Calum

Recent work with DI seems to conflict with that. I don't understand it so I'm not even going to attempt to paraphrase it, but from what I've read if you just look for all out flow your gonna have an engine that runs very poorly.

I've talked about this a lot. High flow ends up hurting the motion of the mixture in the cylinder. GM has recently published a bunch of stuff about the new Corvette DI engine. Guess what they did? They added a swirl characteristic to the old LS7-style heads which required a reduction in flow capability. Without that it had a knock problem.


Right now the main path for n/a mods on these cars is basically full exhaust. You can also do E85--I'm still skeptical of long term reliability with stock fuel system components, but time will tell. There isn't a whole lot further you can go without exponential increase in cost and potential loss of driveability and low-mid range torque.

[StormTrooper]

TB and intake mani with a well designed intake.....probably not much gain but maybe.

[Dimman]

@arghx7 With the D4-S we get the advantage of working with port or direct as we see fit (or do we? Does the ECU tuning software allow independent duty cycle adjustments of the different injectors?), so if chasing high flow we still have a port system if that generates more power.

But I think our current crop if tuners has a LOT of learning to do both with just NA basics and the combination injection , and I don't think most of them will take the effort required to expand their own knowledge.

[arghx7]

Intake manifold tuning helps you in one area and hurts you in another. You can't escape the laws of physics. And it's not easy to fully optimize intake & exhaust manifold design together with cam design. All the dynamic effects involved and tuning parameters (AVCS tuning for example) need a gazillion prototypes or modeling to sort through the optimum combinations.

[arghx7]

Originally Posted by Dimman

@arghx7 With the D4-S we get the advantage of working with port or direct as we see fit (or do we? Does the ECU tuning software allow independent duty cycle adjustments of the different injectors?), so if chasing high flow we still have a port system if that generates more power.

But I think our current crop if tuners has a LOT of learning to do both with just NA basics and the combination injection , and I don't think most of them will take the effort required to expand their own knowledge.

ECUTek does have the ability to control the injection blend between the two but I'm not sure what the practical limits to that are.

I'll say this. If knock isn't an issue due to E85, you're probably better off going with a high flow intake port, high lift cams, etc, and disabling direct injection. But how many parameters do you have to optimize, and how much time and money will it take to get there? You'll have the combustion efficiency from better mixture preparation, and knock won't be an issue. BUT fuel displaces air during the intake stroke, so that can hurt you. Only an in-depth study could tell you what the optimum combination is.

In the end though you end up with sort of like an expensive Honda engine with two banks of cylinders.

[Dimman]

Originally Posted by arghx7

ECUTek does have the ability to control the injection blend between the two but I'm not sure what the practical limits to that are.

I'll say this. If knock isn't an issue due to E85, you're probably better off going with a high flow intake port, high lift cams, etc, and disabling direct injection. But how many parameters do you have to optimize, and how much time and money will it take to get there? You'll have the combustion efficiency from better mixture preparation, and knock won't be an issue. BUT fuel displaces air during the intake stroke, so that can hurt you. Only an in-depth study could tell you what the optimum combination is.

In the end though you end up with sort of like an expensive Honda engine with two banks of cylinders.

The closest tuning experience to D4-S I've read about is on bikes with a close to the valve injector, and a secondary injector per cylinder on the other side of the throttle, further up. At high intake velocity/rpm the 'showerhead' injector sees more use as the spray has more chance to suck out heat and atomize when it smashes into the butterfly.

But the tuning process sounds long and arduous, for small gains (bikes need every tiny gain they can get, I guess).

I just can't see any current tuners here making the kind of effort required, though.

[LeeMaster]

Are there not any benefits for an Intake Manifold for this engine?
I know it made quite a difference when going from an RBB to an RRC on a Honda K24 engine

[xwd]

I kind of doubt it for a NA application.

I am all for making NA power but have to agree with some others in the fact you can buy an Innovate kit for $3500, install it in 4-5 hours, run 5 psi, and make more torque/HP than you ever will NA with a better powerband.

Cams for this car if they eve r come out will probably be $1200+ unless you do regrinds.

[Noob4Life]

Is there even such a thing as n/a power from a 2.0l 4 banger?

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[s0sl0w]

I won't argue that the mpotor is probably fairly close to it's limits for the e,issio s targets they were looking to achieve but I really doubt 200 WHP is as far as we get NA and still retain driveability. Maybe DI changes that but if lifting off the heads over a winter and port matching/ smoothing things out picks up even 5-10 HP I'd think it'd be worth it. Even when I eventually supercharge the motor I'm still going to want to have the motor as optimized as possible beforehand. I'm not talking about an all out crazy na build (as cool as I think that would be) just basic "optimization" work.

[ft_sjo]

Once you start getting about about 120hp/litre n/a it's no longer really a street engine. Who really wants to be driving a lumpy race engine around with terrible low-end performance?

[StormTrooper]

I'd be pretty happy with 210whp and a nice 4k -8k power band.....drop some weight and it'll move out of it's own way nicely.

I think a 150lb drop will be achievable as a DD.....

[the.big.kahoona]

Originally Posted by ft_sjo

Once you start getting about about 120hp/litre n/a it's no longer really a street engine. Who really wants to be driving a lumpy race engine around with terrible low-end performance?

S2000 = 120hp/L

[StormTrooper]

And it had pretty bad low end power....