N/A v f/i

[Muscletang]

We need to be specific on this debate. Different strokes for different engines.



This engine was not made for boost. Yeah, you can get some power from a supercharger and a little from a turbo but it wasn't in the plans. It will run by itself just fine N/A.



We all know that the 2JZ was made for boost. I don't think any of those Supras we see on the internet running insane times are N/A.

Now you may think this is an un-fair comparison, it's not. These engines were just designed different. The 427 is bigger, but the 2JZ revs higher and is a more balanced engine. The 427 has more torque at idle, but the 2JZ has more horsepower in the higher RPMs. The 427 has more moving parts but the 2JZ doesn't. The 427 is very basic and simple to run, but the 2JZ has computers, fuel injection, and modern technology to help it along.

Are either of these engines better than the other? No. I think both were designed very well to do what they do.

[DinanM3_S2]

Originally Posted by blakscorpion21

i would always prefer f/i personally though. more torque, better throttle response, plus easily upgradable for big power.

better throttly response from f/i over n/a? I think not.

[drunken monkey]

how about the F40's engine against the F430's for a similar comparison?

almost like the 427 against the 2JZ except it is the F40 with the "simpler" engine compared to the F430's but both producing similar figures (except torque...)

[kman10587]

I'm partial to superchargers. Sure, you usually won't get quite as high power gains as you would with a turbo setup, but the power you do get is spread out much more evenly along the RPM range. Quality over quantity.

[k3smostwanted]

Originally Posted by kman10587

I'm partial to superchargers. Sure, you usually won't get quite as high power gains as you would with a turbo setup, but the power you do get is spread out much more evenly along the RPM range. Quality over quantity.

depends on the turbo set-up. a well suited turbo choice for a motor will give much better top-end than a supercharger and will be very similar down low.

volumetric efficiency is the key on a debate between superchargers and turbochargers. also, people like to compare a 2JZ single turbo motor made for creating 1000rwhp to a supercharged big block made for drag racing. of course the turbocharged set-up is gonna be weak down low and the power curve will look more like a chidren's slide at the park instead of a steady pace up.

its all about the RIGHT turbo choice.

as for FI vs. N/A. depends...there are turbocharged vehicles ten times more reliable than some N/A vehicles, but also vise versa. but i think in most cases, a properly built FI motor will yield better performance. alot of manufacturers or car builders can use less displacement with a turbocharged set-up which means they can also achieve better economy.

turbocharged vehicles become unreliable due to trying to stretch it too far. you would be surprised to see what a stock low compression turbocharged motor can take. as long as you can prevent detonation a FI car is endless in power. that is the beauty. i have seen my car (Nissan 300zxTT) create upwards of 800rwhp on a completely stock internalled motor. only thing upgraded were the turbos, injectors, intercoolers, and ECU. just some FYI.

[zx2guy]

so then what would your choice be if you were building a stock na motor? would you stick with na or build it for fi?

[k3smostwanted]

Originally Posted by zx2guy

so then what would your choice be if you were building a stock na motor? would you stick with na or build it for fi?

depends...

how well is the N/A motor suited to handle boost? What is the stock compression ratio? how well does the head flow?

when it comes to adding FI to a motor that was never made for it you run into problems with detonation due to the tuning and high compression, though with the proper set-up it will be fine and reliable. but nine times out of ten it will create more stress on the motor than intended, therefore gradually wearing it down in every aspect.

if you want good power gains, FI or nitrous is about the only legitimate choices. sometimes, you can have it all...the more power you want, the more reliabilty you have to be willing to use.

in general, if you were going to spend that much money on the N/A motor to build it and stick with N/A. i would personally go the opposite and put some lower compression pistons in, headwork, and add the turbocharger kit. with the lower compression, you will get the reliability that you may be looking for and also the power you want. you will have to run more boost with the addition of lower compression pistons, but boost acts as like a pillow in the combustion chamber which leads to a much safer running engine.

[zx2guy]

compression if i recall correctly is 9.1 to 1. the head flows really well and there is debate whether or not the stock cams are best suited for boost applications. i was thinking along the lines of what you are.... the concave piston tops to lower the compression. then add a turbo kit. im debating whether or not i want to but a competly seperate head (from gude for instance) to swap out of the stock, that way i still have the stock head. im told i shouldnt have to worry about having to swap to forged pistons and rods until i get about 10.5 compression (give or take).

for right now though im just going for minor mods, short ram intake, 4-2-1 header, either coilover struts or just find lowering springs. i have a whole list but im too lazy to list it... any more ideas? i was thinking about finding a ported throttle body.

[beef_bourito]

n/a will only be more reliable to a point. when you start upgrading a n/a motor, you usually start by removing restrictions and making the whole thing more efficient. so you do things like intake, exhaust, better oil, ignition system, etc. those are things you should do to a fi motor anyways if you want the best results possible. once youve done those you need to start stressing the motor for more power, increased compression, higher reving cam, etc. these will give you some gains but they will increase stress alot and make it unsuitable for daily driving. if you went the fi route, you could slap on a turbo, keep the same redline, have a good daily driver and only add stress when you were hammering it.

basicly what im trying to say it that in the beginning, yes an n/a motor will be more reliable, but once you try to get some huge gains, the fi motor will come out on top in performance and reliability for the same gains.

if i had your car, you're looking for 45hp, i'd go turbo, better fuel economy than supercharger, better top end, only there when you need it, and you'll get those horses more reliably. without changing the intake or exhaust you could probably get those gains from under 10psi. if you upgrade you intake and exhaust systems you wouldn't need as much boost to get your gains. plus it would sound better and you'd have better throttle response.

I'm all for fi in every situation unless racing restrictions prevent the use of it.

[Polygon]

No question, if given the choice, everytime I would go with F/I. Namely I would go with a turbo-charger, I hate super-chargers. Not to say I wouldn't have some fun cars that are N/A but I much prefer having a turbo.