Forged Rods for 300-330WHP?
 

Hi guys, first post here but long time lurker. Need some advice!
I own a 2015 BRZ with roughly 90,000kms, going forced induction this upcoming spring. Kit and supporting mods:

HKS GTIII-RS Bolt-On
Mishimoto TStat Oil Cooler
Injector Dynamics 1050x
Radium PCV Catch Can
3-Bar Map Sensor
Grimmspeed EBCS
Southbend Stage 2/Exedy FW/Clutch Fork
AFR, Boost, Oil Press Gauges

I obviously want the car to be as reliable as I can make it. I understand this is a gamble when going forced induction. I was looking into forged rods as I’ve read this is the weakest link. The car is only used in the spring/summer, never sees the track but does see spirited driving. My power goals are 300-330whp max. I don’t intend on going any further in the near future. Looking at Brian Crower forged rods. I know some may ask why not do pistons at the same time and I do want to do only what I researched is necessary, instead of a “might as well.” My questions are, for my power goals, should I be doing rods? Will the rods fit on OEM pistons? Would I have to consider purchasing anything else when doing rods? Gaskets, seals, bearings etc.? Or would it just be a straight swap from stock to aftermarket.

Any feedback is appreciated. Thanks a bunch!!! Stay safe

I just realized I clicked the wrong sub forum, meant to post in forced induction! How do I move it?

Forged Rods for 300-330WHP?
 

Hi guys, first post here but long time lurker. Need some advice!
I own a 2015 BRZ with roughly 90,000kms, going forced induction this upcoming spring. Kit and supporting mods:

HKS GTIII-RS Bolt-On
Mishimoto TStat Oil Cooler
Injector Dynamics 1050x
Radium PCV Catch Can
3-Bar Map Sensor
Grimmspeed EBCS
Southbend Stage 2/Exedy FW/Clutch Fork
AFR, Boost, Oil Press Gauges

I obviously want the car to be as reliable as I can make it. I understand this is a gamble when going forced induction. I was looking into forged rods as I’ve read this is the weakest link. The car is only used in the spring/summer, never sees the track but does see spirited driving. My power goals are 300-330whp max. I don’t intend on going any further in the near future. Looking at Brian Crower forged rods. I know some may ask why not do pistons at the same time and I do want to do only what I researched is necessary, instead of a “might as well.” My questions are, for my power goals, should I be doing rods? Will the rods fit on OEM pistons? Would I have to consider purchasing anything else when doing rods? Gaskets, seals, bearings etc.? Or would it just be a straight swap from stock to aftermarket.

Any feedback is appreciated. Thanks a bunch!!! Stay safe

Just have a mod move it to the correct sub-forum, or in this case, since you already made a duplicate thread, merge them together.

@ichitaka05

300whp supercharged or 330whp turbo is pretty reliable on oem block. Assuming correctly installed with supporting mods and a good tune.

For the price of doing rods you could just install a slightly used block if yours does go.

Or if doing rods it’s not much more expensive to do pistons for 400whp.

At you’re power goals especially for just spirited driving. Not much point especially if you have good fuel like E85 and or WMI. Or do pistons and make your goal a little more ambitious like 350-400whp depending on fuel.

brian crower rods with tapered end works great and fit oem pistons
oem are good to 500bhp according to Cosworth and Fensport who uses them

i have brian crower rods and they re now even too expensive

I'll add that I am on the stock block with E85 at a bar of boost and headers. Similar people are making 350whp on that setup or more. People have broken the stock block NA, so there isn't a set point where you have to do a build. Your turbo will make more torque than my Harrop kit, so that is a difference. Are you going to use E85? If not then I would do a build if you are concerned about reliability, even for only spirited driving.

I don't have experience with all the different brands to be able to offer advice on rods. I think most will be overkill for your power goals, so no need to buy the biggest and best. I wouldn't get some cheap, eBay rods either. Are you considering doing any other modifications why you have the engine open like ARP headstuds, larger bearings, pistons, etc? My thing is that if I was doing a build then I would do a certain amount of minimum things because I wouldn't want to have to do a 2nd build if I want more boost in the future.

If you don't have access to E85 then you might want to lower compression to maximize reliable power on pump gas.

How is your transmission holding up with that 75 mm pulley on the Harrop? I’m still hesitant to install my Harrop with the 85 mm pulley without upgrading the clutch, clutch fork and throwout bearing first.

It seems to be fine so far. I definitely take it to redline often, and I launch it too. I don't drive many miles, nor do I track the car. I may hold the rpms above 4k with minimal throttle and then gun it, but I don't really drop it down two gears and launch the shit out of it. When I go to the canyons to hammer the corners, the transitions are quick and smooth, and the rpms stay high, so again, there aren't many times when the transmission gets super abused or anything.

Surprisingly, the Exedy Stage 1 clutch seems to be holding fine. I don't put a ton of heat into it. I doubt it would hold up to many track days. I also have the Verus forged fork, Verus billet pivot, AMSOIL, new bearing (white dot) and all the bushings and springs. I bought the car with 45k miles and some fifth gear grind, and besides that, the transmission is good. Feels better with some heat in it of course, but it is good. Sometimes I think the 45k miles helped to season the engine and transmission some, which is why I haven't had any problems.

Sounds to me that I drive a bit more conservative than you do, so I expect my transmission to hold up with E-85 and the 85 mm pulley. I purchased my ‘15 with about 45,000 miles over a year ago with no mechanical or electrical issues to speak of. I’ve driven it maybe 2000 miles so far. I’m not tracking it and I don’t beat the hell out of it. And I never lug it.

My only concern is that I engine brake whenever I drive. I do it naturally without thinking about it because that’s just how I was taught when I first learned at 16. I’ll go up through all the gears and back down through most of them which pretty much doubles the wear and tear on the clutch components. And whenever I pull the car into the garage after even normal, non-spirited driving, I’m getting that foul burning clutch smell. It’s not making any noise or slipping yet, but I can tell that as soon as the Harrop goes on, in just a few miles, I’m gonna have to drop tranny and replace those components.

So you’re still rocking the stock internals? I also thought about upgrading to stronger rods while leaving the stock pistons like OP is planning, but seeing how I’m running flex fuel or 93 AND that I’m having Zach at CSG remote tune my Harrop/flex tune, I’ll probably leave the internals stock as well. I think this set up along with my driving style should be fine on the stock internals and transmission.

I engine brake all the time. It is a habit from motorcycles, so I understand what you mean. 99% of the time, I row down through the gears as I brake.

You really never know. Some would rather build before blowing a hole in the motor and needing to build and replace the motor, but either way, you pay for insurance or gamble and possibly pay more later. I'm gambling. I feel like getting a built motor is also a gamble. I tend to trust factory assembled engines more than ones from a shop or myself, so even if I was to build the motor, I would be gambling. Plus, it would just be an excuse to get the 65mm pulley. Maybe a swap will happen in the future if it goes.

engine break is good, and saves brakes and can save fuel

if you rev match EVERY SINGLE down shift i don't see why you should have clutch smell and clutch will last very long
i'm 50k km in my stock clutch and it still looked almost like new when i saw it out of my car, and half of those Km are with supercharger

^^^
Engine braking and halfway decently executed downshifting through the gears all the time won't appreciably accelerate wear on engine, clutch, transmission.

EVERY SINGLE down shift?

Using engine braking is a lot harder on the car than just using brakes. Also puts a lot of extra strain on the gearbox, drive shafts and rear axles. All reasonably fragile in these cars when pushed harder than OEM requirements.

It’s also a shit load easier and cheaper to change a set of brake pads than pulling boxes and changing clutches, or boxes themselves.

Any fuel savings using the engine to brake would be offset by wear and tear on the engine and driveshaft.

As for clutch smell; that has to be either adjustment which is an absolute shit job to do in these cars, incorrect fitting, faulty pressure plate of sticking clutch plate not sliding on the input shaft, or the driver riding the clutch.