N/A v f/i

this is something we have touching in one of the other forums. and i think its all about personal preference. but if you had a choice in cars or upgrading what you have through one of these avenues which would you go. forced induction (turbo, supercharger), or naturally asperated ( just swapping cams, crank, pistons, ect). i know its vague. but do what you can

Yeah really vague, if there are two identical motors and one is tuned for NA and the other is FI I guess the FI would be preferred. Just thinking...NA Supra vs turbo Supra or 01 Cobra vs 03 Cobra.

ill try using an example to try to convey this a little better.
lets say you have a 03 zx2 (just so happens to be my car...huh... imagine that) it has a naturally asperated motor. i can decide to put on a turbo ( since there really arent any superchargers that are reliable) or i could swap cams, pistons, just about anything but use forced induction. what would you do?

n/a mods on a small displacement engine you will have a hard timing breaking 250hp.

even the 10 second all motor drag honda's only makes 350 crank hp and those things are built to the balls running rediciously high compression pistons, a cam that barely lets the engine idle, head work, a super high rev limit, very very high strung engine.

however with boost, you can make 300-400-700- and some extreme cases, 1000whp on a 2.0 boosted 4 cylinder. the SR20DET's have been known to make 700whp and the 4G63's have been known to put down over 1000whp at all 4 wheels.

if you want to go mild with great throttle response, get a hybrid ball bearing turbo, it will give you near instant response, waay more tq then n/a tune, you wouldn't have to rev the shit out of it to make power, and you can still make 300whp easy with a good setup with great power delivery.

Along those same lines and related to a thread I started:

I was trying to consider getting a RSX-S or a GTi Mk V. One's NA, one's turbo. I dont know enough about turbo's and dont want to get mixed up in it, but I feel like a Mini Cooper S JCP or Cobalt SS would be more reliable than a turbo car like a SRT4, WRX, or GTi Mk V. Now is it right to say that any NA car would trump a FI car in reliability b/c it doesnt have as many things going and an issues to worry about like fuel mixtures, detonation, etc etc.

ok so ill have reliability on my side but i will suffer in way of not reaching very high in hp. thats livable.... i wont have to worry about more stuff breaking... not turbo lag... il probibly just go half and half. ill work on the car i have and make it n/a and ill turbo the car i want (which is the same car just w/ a stick)

I like both and I respect someone's choice either way. They both have pros and cons, but it comes down to the one you prefer. Personally I'd consider nitrous, it's cheap, effective, and allows for everyday drivability while giving you power when you want it.

my only problem with no2 is it leans out the mix so much. ild have to put in a wet system so i dont burn up the pistons or valves. the other thing is the power increments arent to my liking.... i mean if i could add 25 hp... that will put my car at 155. which is good enough. but i worry about adding more then that because im sure ild break something. but the smallest ive seen is 35.

most cars can handle a 70 shot. and thats a dry kit i believe.

and also yeah to a certain degree that a n/a tuned car is more reliable, but if you want to make any real meaningful power, you need do all that i have mentioned and it won't be reliable one bit. super high compression, plus super high rev plus super advanced ignition timing, plus leaner air fuel ratio = stress on rods trying to pull itself apart from high piston speed, alot of heat inside the cylinder from high compression, big stress on valvetrain due to higher rev limit and more lift from cams.

but i you want a reliable n/a you really only are looking at a 20 whp gain, and thats with intake, headers, exhuast, and a chip, and maybe cams. a turbo can almost make that much more power on a nice cold night vs a hot day.

Yeah thats a really good point, as soon as you have significan't power gains regardless of how you get it, you are going to be looking at reliability problems, particularly if you are talking about doing FI on a motor that wasn't even made for it. There is going to be alot more things that will either need to be replaced or be broken.

if looking for big power go f/i, if looking for just a little bit go n/a. i would always prefer f/i personally though. more torque, better throttle response, plus easily upgradable for big power.

stock my car makes 130 ponies.... im willing to bet thats crank, not wheel... what im looking to do is build it to maybe 175.... ish. thats 45 hp. i think if i get a CAI (or short ram), ported throttle body, and do something to the intake, and intake cam. ill have a nice little gain. (maybe 15) then i have a 421 header. ill move the cat (which is in the engine compartment) to under the car... which allows for more options on a cat back. then ill balance the motor (for longevity reasons... not performance), and put in flat top pistons. which will possibly add another 15. these are only guesses though on my gains. so they may be high or low.... i really dont have the tech here to measure any gain.

going a little wilder. if i put in a .400 lift cam the motor becomes interference(... which im not a big fan of the idea incase the belt breaks) and i could put in domed pistons (forged... rods too)to further add compression. with that a stronger bolt kit might be a good idea. ill also build up my tranny (which on my car are notoriously bad to start with) shift kit, any other goodies ill try to think of. oh and there is also a kit out there that will stroke the motor from 2.0 to 2.4.... something i dont like the idea of (i like my high winder... and i dont know how it will effect my motors chemistry) but ill throw that out there for you guys to comment on.

that would be the like a $3000 dollar engine job for like 40 hp gains. if thats how you want to spend your money, then be it. but $3000 you can get a blower and make atleast 75hp more, with decent reliablity too.

run a 100 shot, zetecs will take 100 shot's stock..


your tranny however... :lol2:

that would be the like a $3000 dollar engine job for like 40 hp gains. if thats how you want to spend your money, then be it. but $3000 you can get a blower and make atleast 75hp more, with decent reliablity too.

i have yet to find a good reliable SC for my car... ive found a few, but ive asked one of the guys in the zx2 forum, who has worked on these cars since 98. and he has yet to find one that he would reccommend(and ive done some of my own snooping and i tend to agree). in fact there are 2 really
knowledgeable guys there one is altec and the other is skater in ny.

this is whats limiting me to either turbo or na status. ive found a guy that builds turbo kits and of all the turbo kits ive found he is the cheapest(but the best). for his stage 3 its only like $1750. but i can go through gude (but they have fitment problems) and go for a head and turbo for 2800(good kits though). thats not including what ild have to add in the bottom end (forged pistons... anything else i feel like doing). these are my basic options. im a little afraid of adding a turbo... for all the reasons you could think of. which is why i like n/a but it is more expensive. and me no liky nos< i tend to break shit when i have power at my finger tips.

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

http://www.gessford.com/cobraparts/images/Toms427SOMidstates008.jpg

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.

http://mkiv.com/techarticles/parts/reg_engine/JZA80008.jpg

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.

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.

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...)

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.

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.

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?

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.

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.

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.

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.