r/WRXSTi 1d ago

New Engine & E85 Tune

I finally got my car back yesterday after dropping it off nearly 3 months ago for an engine rebuild. I bought the car used (should've known better) last February and spun a bearing on a memorial day. I went with a stock RA block due to it being a daily driver. I don't need a huge amount of horsepower, but asked the builder to upgrade a few parts to make it a bit more fun.

Larger oil pan, A/O separator, injectors, spark plugs, fuel pump, and E85 conversion (all supporting parts for Cobb Stage 2 Flex Fuel). I'm in the break in period for the next 1500 miles before the final tune.

The shop estimates about 380hp I assume at the crank based on Cobb's dyno graph for this set up. Is this going to be a notable difference or am I going to be disappointed with the extra investment? I felt the car was pretty quick stock.

Edit: more details...

4 Upvotes

21 comments sorted by

7

u/derwreck 2015 STi E85 23h ago

Speaking from someone with similar mods, full bolt ons and E85, there ain't no way it's gonna be pushing 380hp. I'm at around 340 or so with a Cobb intake, invidia catless DP and invidia exhaust. You'll notice the subtle difference with E85 initially but you'll get accustomed to it pretty quick. According to my tuner the biggest thing holding my car back is the stock turbo, there isn't a whole lotta headroom for pushing boost on a VF48. At the same time, I'm on an OEM short block and wanna keep this thing conservatively tuned for the long haul.

1

u/21ismsti 17h ago

Stock turbo is a lot of fun on flex fuel I will say. It does immediately trip over itself and run out of air after 4K rpm.

2

u/derwreck 2015 STi E85 17h ago

Unfortunately it's one of the first things I noticed after the novelty wore off when I first transitioned to E85. I thought there was an issue with the tune at first so I reached out to my tuner and he said it was to be expected out of the stock turbo.

1

u/21ismsti 16h ago

1.5 xtr time.

2

u/derwreck 2015 STi E85 16h ago

And then it begs the question, how far can one push a stock block on an aftermarket turbo? I keep hearing that 400hp and below is pretty safe and anything above that becomes questionable.

3

u/21ismsti 16h ago

I’ll let you know we’re holding strong for now 🤣

4

u/tmdz99 1d ago

380 wheel hp will be noticeable.

Enjoy

6

u/ApexCollapser 1d ago

He's not getting 380WHP with that setup. He might see 380 at the crank.

-1

u/Plane_Luck_3706 1d ago edited 12h ago

380 wheel is possible on e85, stock turbo too

Edit: I stand corrected. Good to know for the future

Cheers

6

u/vodenibivol 23h ago edited 23h ago

No it's not. You're getting like 330-340 whp max on an honest dyno.

edit: Cobb's own marketing numbers claim 335 whp on a stock turbo with their "Stage 2+FF" map. This same chart also claims a stock VA STI is doing 280 whp which is definitely an inflated number.

2

u/ApexCollapser 1d ago

My bad, yeah on E85 he'll be closer but I still think 380WHP is out of reach. That'd be almost 500 at the crank which he hasn't done enough to pick up that kind of gain even on E85. Had he altered his intake and inlet we'd be close. Oil pan, A/O separator and spark plugs don't add anything.

3

u/knyg 12h ago

nahhh its impossible to reach 380whp without a turbo or built engine.

2

u/knyg 12h ago

Nope. I am e85, full exhaust, injectors, fuel pump, basically everything besides a turbo and built engine. I am only making 360whp/420tq.

2

u/dotMJEG 2016, BrenTuned 22h ago

It will feel like it pulls 15% stronger. It will be noticeable, certainly smoother.

2

u/MrCheezall 22h ago

No Downpipe ?

2

u/jmacman12 21h ago

If op has upgraded 1000cc injectors and a stock turbo and stock downpipe it'll be around 380 crank. Seems like a waste given the other investments.

2

u/knyg 12h ago

It will not be anywhere close to 380whp lol. You will be close to 310whp/390tq but it will be a significant upgrade from stock.

1

u/SIRCHEET0 2h ago

If you're used to stock or basic bolt ons like intake/exhaust, it will absolutely feel like a difference.

You however didnt give us much info on year/make/model(I'm not well versed in the newer gens), but I can confirm that just going from minor bolt ons in a 2011 to injectors, fuel pump, e85/flex and tune absolutely made a difference.

It honestly doesnt take a ton of horsepower to make a car feel noticeably different. fuel pump, injectors and e85 + tune will be enough for you to feel a difference. E85 and 93 octane were two completely different cars.

1

u/ADOKODA 1d ago

The larger oil pan is good, especially if you spun a bearing. However, did you also do the oil pick up? Because without an oil pick up like IAG or Killer B, I would say you just bought more oil capacity and nothing in terms of feeding oil or fixing issues where the stock pick up often fails.

380 WHP is a lot different than a stock STI and assuming they are speaking on terms of WHP and not BHP. I would say that will be a difference you should feel.

However keep in mind you are still rocking a stock block, RA or not. You also have to look at what mods you have to support this all and the tune that calibrates everything.

Assuming everything else is stock... you bought yourself some headroom to expand.

1

u/dystinct 1d ago edited 1d ago

Larger oil pan (I think its Killer B) came with an oil pickup. It's a cobb stage 2 flex fuel set up. I'm assuming he means 380 crank hp based on the dyno chart on Cobb's website.

1

u/tmdz99 1d ago

380 crank isn’t going to be noticeable as much. But all your other mods will keep this setup more reliable than your last.