Supercharge or not, need qualified assistance
 

I have 2020 European BRZ Automatic and am thinking to supercharge it. Not planing to race it, just want it to have a better pull and not rev engin all the time till 7k. Not planing to modify engin in any way to support the mode, or fuel pump/injectors. Keep everything stock except for exhaust. I don't expect any crazy boosts. I spent some time looking through all options but need assistance from this awesome community to make right decision.



I live in Turkey (Easter Europe) and servicing Subaru BRZ here is insanely expensive so is to buy any parts. Hence my first priority is reliability. If installing supercharger in any way will put me on borrowed time, I will not do it.

If I will move forward with supercharger I also need to get the most reliable kit with minimum maintenance. Changing any parts will cost alot here assuming they will need to be shipped overseas + taxed for import.



I did some research and based on it I'm considering only centrifugal superchargers and only ready bolt-on kits. AFAIK centrifugal ones will provide more boost in higher rpms which I believe will be easier on the engine. No e85 fuel here, only regular 95 octane. Since shipping and import taxes here are insane I plan to buy a kit when I'm in US next year.



I've lined out some of my questions:



1. will installing supercharger put my engine on borrowed time? After doing some research in order to prevent damage to engin and automatic transmission boost should not be more than 280 whp. If there is any chances supercharge will blow an engine - I will not do it as it will cost hell to repair it here.



2. which centrifugal supercharger bolt-on kit you could recommend as the best value and reliability package. I plan to buy only kit, tune will be done custom by the tuner. I'm also looking for smallest package kit as I will have to bring it with me in the airplane. I was looking at Jackson Racing kit.



3. if boosting the engine with supercharger will bring risk of blowing the engine, will changing whole exhaust with bigger diameter and tuning the engin provide any increase in power and exterminate or minimize tork dip? If yes which headers to use, EL or UEL?



Is there anything else I need to know?



Thanks

Centrifugal will be a little more forgiving than a roots/twin screw supercharger. We have a Sprintex on my wife's automatic BRZ and it has been great so far. These little automatic's are pretty stout so it shouldn't be an issue for you. But nothing is immune to breaking, even stock cars break.

I don't know much about the different centri kits for these cars. I have only really delt with procharger and vortech before and they were on corvette's, Mustang's and such but vortech makes a very nice kit for those cars so I assume the same goes for the 86 platform. So either Jackson Racing or Vortech gets my vote.

The supercharger will take away the torque dip so exhaust is up to you preference wise.

Yes of course there's a chance the supercharger will blow the engine. You're almost doubling the power output of the engine and expecting reliability to be the same as before? /end thread

Expect it to break. Period.

So I've recently SC'd my BRZ with a positive displacement blower and here are my thoughts.

When I think about this topic, there's no other way to put it than in the words the people before me have stated. You have to expect for it to blow at any moment no matter how much care you take in avoiding that. There are so many variables that go into whether or not the engine is going to keep going, most of which may not even be under your control. The engine components will be under significantly more stress than the engine package was designed for. There is a risk of popping no matter what. It may never happen or it could happen immediately. The only thing that is certain is that there is now increased stress on the motor and there is no way to determine if the motor is going to be able to handle that stress over time.

However, that does not mean there are not things you can do to try and prevent it. Just know that you can perform all these things and still have the motor go boom. There is no golden key to keeping it safe after boosting. For example, a good tune on a bad kit is probably going to be safer than a bad tune on a good kit. At the end of the day, the tune is in control of giving the engine the fuel and timing it needs to do it's job. The tune can tell it to work at it's minimum, or tell it to overwork. An experienced tuner with experience with this platform will hopefully be able to get you a "good" tune with your use in mind.

You mention you don't want to install any supporting mods, but the whole point of supporting mods is to be able to support the power and heat levels that something like a boost kit brings, helping the motor not work as hard to support your power goals.

• Oils at hotter temps will break down quicker causing more wear to the engine components. This is where an oil cooler comes in.

• Is it hot where you'll be driving the car around? Where I live, regular temps greater than 105F/41C basically required me to upgrade the radiator on the car stock just to go drive it around spiritedly in the canyons. A boosted application might make that a bit hotter.

• A header that is better at scavenging exhaust gases will help the motor pump more freely, keeping combustion temps lower, preventing pre-ignition and knock.

• Ethanol fuels. I know you mentioned there is no access to that, but ethanol will also help keep combustion temps lower.

These are all examples of supporting mods that don't necessarily need to be used to make more power but can help safely handle the power a bolt on SC kit is going to supply. There are also a number of things that can go wrong outside of the motor blowing. There's a couple threads on here of some AT models breaking gears in their transmissions, breaking axles, having the extra vibration from the motor rattle something apart and who knows what happens.

I'm not trying to persuade you to not supercharge the car. I'm trying to portray that there is an inherent level of risk in doing so that should be known going into it, no matter the combination of parts and tunes, and that it would be ignorant to think otherwise. There are hundreds, if not thousands of people who have successfully boosted their cars safely and unsafely and haven't had a problem since. I'm sure it can be replicated. However, the opposite is also true. The number of people I've known personally who blew their motor stock, spun a bearing backing out of their driveway, had a rocker shoot out their head of no fault of their own, etc. There's just no level of certainty with any of it. :)

If you can't afford to replace the motor don't do it. Plain and simple. These cars on boost need a solid tune with a good install. anyone of these slightly out of wack expect to shorten the motor's life

Well, some things can go out of whack more than others but you have to know how to stay on top of it. Plenty of folks I know have done well but all have enjoyed an interesting variety of issues. It's really a lifestyle choice.

This. I am mentally prepared to pull that motor when mine pops and deal with all the consequences of it.

From what you want , I suspect a centrifugal is not the best aka you don't want to rev the motor out , a PD SC is best in such cases as it gives constant boost from low down and not build like centrifugal. Without headers , will it remove torque dip, PD yes , centrifugal not sure..

As others have said there is an inherent risk in adding boost and challenge is not max HP or torque, it is peak cylinder pressure which should be below a threshold which your tuner really needs to know about.
Just do headers and a tune to eliminate torque dip and drive happily with no additional risk. UEL or EL is much of muchness..

Sent from my SM-G781B using Tapatalk

Thanks for valuable info guys, really appreciate it. Best community ever!

No, I’m not prepared to change or repair the engin of it pops.

Plan B then. Will deleting cat and increasing full exhaust size with low restriction help gain anything and eliminate or level the torque dip? I can have custom tune done on the engine.

I’ve seen several posts that ELH help eliminating tork dip after the tune.

Thanks


Sent from my iPhone using Tapatalk

100%. I personally ran a catless EL header with a good tune and it woke it way up. The torque dip may not necessarily be gone depending on the header you choose, but there will be more torque all over and feel much better. It sounds like this will also suit your expectations more.

I have an HKS supercharger on my 14 FRS 6MT. Works great. I bought the kit with the HKS tablet and had it put on by a professional shop. Works well, no engine codes and I haven't gone nuts with a new header and tuned it even further yet.

The SC comes on very progressively and maintains the current attitude of the car. Below 4500 rpm, it's civil and still a grocery getter that I shift a lot less when I need to speed up a bit. Above 4500, it's go time as the phaser cam timing shift and boost really kick in. They really go well together at the top end.

Again, just on the safe base tune from HKS. No complaints. I know there's more there, but it's plenty for my daily so far. I've put about 10k miles on it since a myriad of upgrades supporting said boost. Namely new bushings to tame the stiffer clutch and extra power.

That's a different aspect of the upgrade you should be ready for. More power makes these cars more twitchy. I created real issues by putting in a 350 ft lb clutch vs the stock 190 ftlb range clutch. Really messed with the rear diff bushings and created a lot of diff flop and wheel buck at low speeds. ikely no issue with an auto, but you may want to put some stiffer bushings in the right places before you're 100% happy. I sure had to. I have replaced engine mounts with STI bits (no NVH) and added several whiteline bits to the rear, and removed one. I have the subframe helpers, diff outriggers, and just replaced the diff insert kit with a Cusco brace. Skip the inserts and bushing replacements, the brace was an instant change abating the last little bit of stiffer clutch leaning into the bushings too hard. And the NVH was negligible if non-existent of a change.

Heya, i've been supercharged and FBO for almost 24k miles now. Lemi tell ya, it's not worth it. You're spending so much to squeeze out only about 40whp on this platform. Multiple things will break, it will cause headaches.

40whp? Something's definitely not right with your setup.

Even the most basic 50-state legal setup should net you 70+ whp.