FI options: Turbo or Supercharger
 

Hi guys,
I'm trying to get a rough plan and mod list for my 86 and would like to get some opinions on the two different FI routes(definitely will do one).

My end goal for power is around 325-350 Horsepower and this will likely be my daily driver for a little bit but will get workouts on track, hill climbs etc.

Personally I love the lure of the turbo, efficent power and a blowoff noise, who could argue with that. But i'm a little concerned about the heat produced by dding, a less linear power curve and honestly i am a little overwhelmed by options and setups available, so any help with the best setup for my goals would be great.

The more responsible side of me is pulling me towards a supercharger, specifically a Harrop supercharger, mainly because they are local to where i live and also seem to give reliable results. I like a linear power curve for DDing however i am a little concerned whether a supercharger can reach my goals, even with an e85 fuel upgrade and tune.

I will likely being doing exhaust mods, after market headers and catback if i get the turbo kit. Just a catback if i get the turbo kit.

I am happy to upgrade fuel injectors and run an e85 tune however ideally not run on e85 all the time, change to e85 for the more intense use.

Thanks for your help guys!!

TL;DR
Goal:325-350whp DD/Track car
Question: What forced induction route suits that goal?

I think you know which way to go!

gives you somewhat an idea

turbo is funnier always, and i m saying this with an unrestricted hks supercharger

From purely an engine reliability stand point a turbo can be setup to be much easier on the engine. Turbo has a lot less parasitic drain on the engine, and less load on the engine so you can make more WHP at the same crank HP, and with much less boost needed. heat issues with a turbo are a concern but if its a pure DD it wont be a big deal.

To have any chance of being somewhat reliable on stock engine 300whp is the max for a supercharger 325whp for a turbo. Even then its pushing it. but depending how often you are actually using that power.

How a turbo makes power (when/where/how much, lag etc..) is way more controllable compared to a supercharger, a lot of it is dependent on the size of the turbo and you can also run boost by gear or boost by rpm to control this more as well. Supercharger will always have the same general "curve" you can only make it bigger or smaller by swapping pulley sizes.

also keep in mind with turbo lag, even if you see a turbo making full boost at 4000rpm if the pull started at 3500rpm it took 500rpm to spoolup, if you are driving normally and downshift to 5k all of a sudden to start a pull it wont be making the power the dyno showed at exactly 5k right when you downshift, it'll take a second to spool up and you probably wont be "matching" the dyno plot until 5500rpm.

Supercharger is entirely linked to rpm and throttle opening. they are incredibly responsive and you will always be "matching" the dyno plot at wot. A positive displacement like harrop, edlebrock, cosworth, sprintex they can make a lot of boost down low very quickly and instantly as soon as you get on it no waiting time but become less efficient top end, the powerband they make is very fun and enjoyable and even when casually cruising DDing you will always be utilizing some of the extra power in the mid range. but that instantaneous low end torque is also what snaps rods. They make the car feel like it has a strong NA 3L V6, less of a "turbo kicking in boost" feeling.

centrifugal sc is the option many like to go because they lack low end and eventually at high rpm start building some great boost/power. They can have a lot of good applications for track/autocross cars, but this is my least favorite option for a DD, a turbo can do anything that can do for a DD but better, just set it up and control it to your liking.

Turbo does not pull power on the crank but it is a restriction on the exhaust flow. My preference would be free-flowing exhaust and an efficient supercharger over turbo.

Turbo

Turbo generally requires more expensive support modifications for heat management. I would not ignore those requirements. If you are going to aim 325-350whp (which is significantly higher than a basic kit provides) without building the engine, I would recommend a special tune and boost control that reduces the torque at low rpm. If you aim maximum torque at low rpm without building the engine, blow up risk will be high. I wouldn't do that.

Depending on his budget there are solutions to fully fix and resolve any potential issues/problems a turbo at 325+whp would create. I agree for tracking the car it would require a lot of supporting mods. For DD and canyon carver the list is much smaller.

Well, that power level without built engine and proper cooling is not something I can enjoy even for DD. There is simply not enough reliability margin. But, sure, I can only speak for my car.

Turbo all day, for the noises alone

This is a bit misleading since you didn't also mention it as a con for turbos. A properly sized turbo makes target boost at an earlier RPM than PD superchargers and present more danger to the rods. PD chargers need rpm to increase boost too.

Also didn't see mention of the potential for turbo install/maintenance issues that can result is boost spikes. Boost spikes can destroy an engine quickly and gear-driven chargers don't have that exposure.

did you ever saw a log of a PD, at low. rpm and WOT?

Anyway, boost spikes are tames by a boost limiter, so if the tune is well done, turbo can be safer than PD

This is like debating boxers or briefs. There's pro's and con's to each but it really all comes down to personal preference.
NA=Commando
Turbo=Boxers
Root/Twin screw=Briefs
Centrifugal SC=Boxer Briefs
Personally, If I lived in Australia and Harrop was in my back yard, just for that reason alone...Harrop all day long. :D

I didn’t go into exact details, but outlined that the size, how it’s setup, and using boost controller for BBG or BBRPM can determine boost curve and give you complete control of it how it ramps in. Also I mentioned a typical turbo will take around 500rpm to spool up once at WOT, and who goes WOT under 5k rpm besides in 1st gear anyways. If your cruising in 6th at like 2500 rpm down shift as your going WOT you won’t instantly be at full boost even if your at 5k+ rpm after downshifting still needs to spool up (unless brake boosting), But yes if you go WOT at 3k rpm by 3.5k if you didn’t use a boost controller you could be making near peak boost.

My PD instantly makes 10psi at 3500rpm at WOT and slowly ramps up to 13psi at around 6500-7k, so not instantly at max boost but still making a lot of boost at low rpm, much different than a centrifugal charger. And with zero lag or spool up time it comes on instantly directly correlated to throttle opening.

There is a reason car manufacturers usually use turbo over supercharger. Once setup right, it’s way better. Never said It was easier to setup correctly though.

Looking at an Edelbrock log right now that shows ~5.5 psi of boost at 4000 rpm. Am I looking at bad data? https://www.delicioustuning.com/d-bo...k_tune_package

And you don't have to set up a boost limiter? Is it as fool proof as a supercharger? Is it not fair to say one should have to the qualify their statements rather than just assume everyone with a turbo adds all the bells and whistles and pays a pro to install it?

Aren't the details important in a discussion where it's posited that turbos are safer than superchargers? Sounds like you need a few bells and whistles and extra attention to detail on the setup before it starts getting "safer" than a supercharger.

I'm comparing to turbos not centris. Maybe I have bad data from Delicious Tuning website but looking at 2 different boost plots I'm seeing ~5.5 psi at 4000 rpm?

No but it was implied.

If they didn't offer superior gas mileage on the EPA tests they'd probably just use the PD (as several do/did anyway) for packaging simplicity and less thermal management to deal with.

See above

Use a photo viewer and zoom. It's clear enough to tell it's not close to 10 psi at 3500 rpm.

The log does show RPM and MAP pressure. It's a run to redline so I can't imagine why it'd be at anything other than full throttle.

I'm not reading into anything. You said 10 psi at 3500 rpm on a PD kit and I think that needs some backup since my research and records, which was all done before I bought a PD charger myself, suggest otherwise.

.

Turbo pressurizes on the intake while blocking the flow on the exhaust. The poor engine is in between, it is hard on the engine, hard to tune, laggy, hot, and overall stupid idea. Now, I am ready to embrace the flames :popcorn:

all you said, but the stupid part

Well, that's for the popcorn

Which one gets better MPG at partial throttle, low load/cruising?
Which one makes more WHP at the same crank horsepower?
Which one makes more WHP at less boost pressure?

See answer to these trivia questions below.



















Turbo

No other FI option gets better MPG then JRSC. Never seen any turbo kit better than the stock NA engine in gas mileage where JRSC is actually better. on my car.

Nobody measured/posted crank horsepower here.

I think JRSC makes ~260 WHP at 9psi. Is there anything better at 9psi?

All of the "turbo is best" arguments are based on low rpm torque which people think increases driving fun. And, this is funny, most of them drive manual but too lazy for downshifting.

Turbo literally kills the spirit of this car and blows up the engine. :cheers:

.

I understand it's a personal preference, but can you explain why or how you set your goal of 325-350 wheel horse power?

well, not with SC, and normal petrol

with turbo you get that with normal 91oct without ethanol :)

guys. i got a hunch, but something tells me he's a fan of turbochargers.

Sent from my SM-G950U using Tapatalk

i m too a fan of turbo, and i put a supercharger in my car

86toyo just put on the table objective facts about each other, if you read him good, you ll see he s right in every statement, and those don t imply subjective opinions, like some other s still doing

I make that at 5.5 psi with my GReddy T518Z

I also have a supercharger. There is no perfect universally right answer for everyone, it's up to each individual to gather all the facts and decide for themselves. Turbos make a lot of sense for some, PD SC or centrifugal SC for others.

for a low budget (relative) FI track car i would do a centrifugal like JRSC.
for a low budget (relative) FI DD i would choose Turbo.
for a high budget (relative) FI track car or DD i would choose Turbo.

I chose PD SC myself because for a DD it is better than a centrifugal SC, in my opinion. But I do all the work on my car myself, and didn't trust myself to do a proper turbo setup at the time i installed the SC so PD SC it was.

So you could say for a FI DD that is your DIY weekend project i would choose a PD SC unless you really know what you are doing when setting up a turbo.

Can you explain how? Just tune, header, larger turbo, E85 ?

The T518Z is a small turbo. Going with a larger turbo will not change the HP that much at a specific psi. It will change when the boost starts and how much max boost you can get. I believe that turbo is only good for upper 300hp range. In order to make more HP at the same PSI you have to control IAT and have a good tune. I am sure CSGMike can have a more detailed explanation. Plus his explanation of a “Properly” sized turbo for your goals.

And there is only one correct answer when someone asks if they should turbocharge or supercharge their BRZ...... “Yes!”

I agree with your answer. I am just trolling with turbo fanatics to leave the counter arguments in this thread.

Trolling is intentionally deceiving or lying for the sake of a response or reaction. Not sure how that adds value to a forum/thread.

bigger turbo will have more air flow than a smaller one at same Psi, so a bigger turbo will give you more hp for less boost
and also make engine less knock prone so shitty-fuel friendly
only downside of bigger turbo is slower spool, but brings only advantages.. also IAT (actually proper name is Intake Charge Temperature for a FI car) is lower with bigger turbo, for the same HP compared to smaller
"properly sized" would be a kind of compromise between fast enough spool, and max hp
Those 2 are one the contrary of the other in the choice of turbo size

All of my arguments are facts, or as conceived as facts. The value I add is countering loudness of fanaticism. That is what I call trolling.

You either restated thing’s already said (which is fine to add reassurance) or just said false opinions/lies/mad up fiction. (Which is trolling, and adds no value). But I don’t see any NEW unique fact that you added to contribute value. But to each their own. Can’t control the internet. 🍻

I don't need your approval to state anything. So you would control internet if you could? What a narcissistic idiot you are.

Actually that's on ACN91. Just a good tune. This is with a stock front pipe in place too.

Turbos don't have the parasitic loss of a supercharger, so the power difference is what the supercharger is eating, all else equal.

100% Agree. Everyone deserves mild/reliable boost!

Because I'm not pushing big boost, a "more efficient" larger turbo is not actually more efficient for me. This can be determined with compressor maps and/or looking at intake charge temps vs pressure.

The T518Z with ethanol, will easily clear 450hp crank/350whp. In fact, I do so on only about 10.5 psi. More boost than this goes into diminishing returns, and really should be done with a larger turbo, but I'm okay with the power I have!