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Off-topic, my apologies... Just couldn't justify creating anew thread for this:

Is there a thread where users list their mods/mileage? I am having an inner struggle about whether to modify my '15 STI or not since I have the 100k bumper-to-bumper powertrain warranty and I am realllly worried about ringland or rod failure.

If I were to modify, it would be: Cobb AP, Cobb SF intake, Church Protune. I assume you can always ask for a super-conservative, reliable, safe tune... no?
Don't bother if you aren't going at least aftermarket downpipe

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Ok, so you are at maximum power and it wont go higher. That's not a reason to shift though because you lower it shifting early, and you loose time doing it, and force more early shifts down the road.
^That is correct. As for the science behind it, Engineering Explained just posted a video a while ago about this.

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When does your torque drop out and where is it at its fattest. This is what I use to use when drag racing.

Shift to stay in the meat of the torque, do some runs at different rpm shift ranges and look at your times.

I found that when I dropped my shift rpm in my old Nissan R33 25/30 I was quicker andhad better mph.

All I can say is experiment and take notes.

What gear and rpm are you trapping at?
 

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I'm doing this exact setup and getting tuned on Monday. I'll post results. My supporting mods are a bit more elaborative, but I wanted to do things the right way the first time.
 

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you could quite possibly be correct :) im not really sure what would yeild a quicker 1/8 or 1/ per say, im def not a dragstrip guy
Either am I, but not shifting early affect track and "commuting" even more!

you can reach max boost (and it holds there) far before redline, and if u smash that pedal to the floor (100% requested load) your gonna run out of runway by the time u hit 6k ish no . . . the heads literally cannot flow anymore.
Sure to full boost occur at spool-up for "us" between 3300 stock and say 4300 big turbo. But I'm not understanding

^That is correct. As for the science behind it, Engineering Explained just posted a video a while ago about this.

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When To Shift Gears For The Fastest Acceleration - YouTube

Thanks tastetickles, good vid! Explians quite well :)

Essentially what it says is that you want to be in the lowest gear you can be until torque and gear ratios combined start to fall off compared to the next gear/rpm combination - and this will always be after your engine torque has started to fall off. A dyno or pull in a single gear does not show this. How much the torque should fall off depends on your gear ratios and how much torque you are loosing. and we haven't even bothered with all the other benefits of not shifting early. I will say that you shift a stock STi at 5800 cause it really does fall flat on its face. This is not true even of my "mid sized" 1.5Xt turbo. My car? 7K gears 1-3, perhaps 6800 in the higher gears, not sure if that 4th or 5th up. No I haven't done the math (I will though), but you don't need to in my car. It is very obvious.


When does your torque drop out and where is it at its fattest. This is what I use to use when drag racing.

Shift to stay in the meat of the torque,
You loose torque at the wheels when you shit into a higher gear. You need to take this into account and it will always turn out that you go to where your engine torque is falling off significantly. Watch the vid. They got this and explain it well.

do some runs at different rpm shift ranges and look at your times.

I found that when I dropped my shift rpm in my old Nissan R33 25/30 I was quicker andhad better mph.

All I can say is experiment and take notes.
Sure :)

What gear and rpm are you trapping at?
Me? I don't race and I have no interest in drag. If I could afford a track car and had time to use it, then I might do the quarter just to learn more about the car, not sure it would help that much though.

And to xyzyx00, Yes If I thought my engine was performing how you say, then I'd be looking into eliminating the limiting factor whatever it is. You have a narrower powerband than a stock STI which already a narrow powerband. You might actually have a faster car going to a smaller turbo, getting earlier spool and being able to run it out to redline! Narrow powerband is making you shift early and you lose effective toque, torque at the wheels.

Finally I'm not understanding what your are saying about heads not flowing more than any number with higher RPM, IE if that is correct I don't understand why. It sounds more like a turbo issue.
 

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In my opinion if you dont at least take a modified car to tye strip you are missing out on vital performance data.

Ive seen to many happy dyno's, to belive what they say, good tuning tool, yes, reliable for power increase, no.

I have used the srtip to evaluate every car Ive owned, without hard proof there is no bragging only speculation..

1/4 mile time and MPH dont lie. even on street cars.
 

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Not bragging. Don't care what you or others think. My car is for me.
Anyway particularly uninterested in drag. If I were wealthy I'd track - with a track car.
 

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I advocated for the Cobb 20g turbo in this thread. Here's my results from today tuning session.



This is the mod list.

2016 STI

Exhaust:

Cobb Turboback
Cobb 20g Turbo Internally Gated
Perrin “Big” (2”) Equal Length Headers
Perrin “Big” (2”) Up-Pipe

Intake:
Perrin Cold Air Intake
Perrin 2.4” Turbo Inlet
Perrin Front Mount Intercooler
Perrin BPV Recirc
IAG TGV Deletes
IAG 3mm Phenolic Intake Man
IAG Secondary Air Pump Deletes

Fuel:
Cobb Fuel Stumble Fix
Cobb Fuel Pressure Regulator
Cobb 1000cc. Fuel Injectors
AEM 50-1215 320LPH Fuel Pump
Cobb Fuel Pressure Kit with Sensor
Cobb Flex Fuel Kit

Engine:
IAG AOS Competition
IAG Secondary Air Pump Deletes
Killer B Oil Pan, Pickup Tube, and Baffle
Motul Excess 5-40w
Visconti Speed Density Kit.
Cobb ECBS 3 port
PST Carbon Fiber Drive Shaft
 

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Back to OP's original question I totally agree with yamahasho's comment. To get to around 300whp you only need a dp and good tune. My first mod was a crawford dp, aos and cobb ap with a protune and ended up at 289whp. This is in the DC metro area, so basically 0 elevation ('09 sti). For me, turbo change only comes into play if you are shooting for much higher whp.
 

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Back to OP's original question
The OP's orriginal question was

"Best Turbo upgrade for stock Sti?"

The answer might well be none . . . but the wording left a lot of room for discussion.
 

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I've got a 2019 STi. I have the Cobb 20g, full Cobb ethanol kit, air pump deletes, TGV deletes, Cobb downpipe, Tomei exhaust, Cobb turbo inlet, Cobb intake, Cobb BCS, etc. My car made about 300 wheel hp and wheel torque at altitude (91 octane at 5,280 feet) and 365.2 ft lbs of torque and 367.8 wheel horsepower on E85, again, at altitude. The Cobb 20g holds boost to redline. 4th gear pulls decently hard for what the car is. 1-3 gears pulls pretty hard.
 

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Deleted wrong thread
 
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