Engine Choices - Advice Revisited

[Blwalker105]

OK, so I'm having a difficult time deciding what route to take with my engine choice. Here are my specifics and goals for my Coupe:

I have a new FP HTA71 turbo and am planning to go with an AccessPort setup, equal length headers, and all the supporting goodies. I am looking to make a conservative 350-360 WHP. My donor car is a '03 WRX with 225,000 miles. I plan on beefing up the stock transmission with all new bearings, Rallispec STI gearset and bearings, new Cryo-treated ring and pinion and a Quaife.

If pressed, I can put around $5000 into the engine, but I'd rather do much less.

How about a little input on whether to:

A.) totally rebuild my 2.0 with forged pistons, new oil pump, balance the rotating assembly and have the heads refurbished.

B.) procure a IAG 2.5L Stage 1 block and make it a hybrid with my refurbished heads.

C.) try to find a complete used 2.2L or 2.5L engine with less than 70,000 miles or so and just bolt it in.

Thanks Bill

[carrera1984]

I'm going to not included WRX blocks and just post up STi information as your wrx is up on miles and there would be no reason to replace with anything other then an STI 2.5 block.

Bare bone I would consider a STI short block with 2.0 heads. This is called the hybrid build and is a great option! You get the power handling of an STi but value of reusing your heads/accessories. STi blocks are cheap and handle 350whp-ish. The good part about this is that the tolerances are subaru factory specs, which means the engine itself will last longer. When you start getting up in HP requiring pistons and other internals, the tolerances increase to allow for heat expansions and such. Engines just don't last with those specs.

Next up would be the STI block with aftermarket pistons. Pistons get you up to 350-400whp. You could get a STi long block or go 2.0 heads again. Just remember the 2.0 heads will flow less. This requires non Subaru specs and aftermarket pistons will be installed by hand. Prices goes up for hands on aftermarket labor. People aren't just pumping these out like a factory assembly line. Price goes up!

Of course the communities around the WRX/STi platform are huge and will have varying opinions. There are guys running 400whp on stock Sti block. Will it handle this. Yes... but for how long? Will the WRX block handle 330whp, yes but for how long?

How much can a STi block handle?
http://www.iwsti.com/forums/2-5-liter-litre-factory-motor/95383-how-much-horsepower-can-stock-ej25-sti-take-before-blowing.html

STi power progression
http://www.iwsti.com/forums/2-5-liter-litre-factory-motor/285399-sti-power-progression-gainz-shooting-stars.html


2.0/2.5 Hybrid build - Google it, there is so much out there. Try to find a current pricing thread for an idea on real costs involved.

OEM STi Block $2,279$
http://www.revworksinc.com/Subaru-OEM-EJ257-Shortblock_p_180.html

STi block + pistons & bearings $2699
http://www.iagperformance.com/IAG-Stage-1-2-5L-Subaru-Short-Block-WRX-STI-LGT-p/iag-eng-1000.htm
http://www.revworksinc.com/Rev-Works-Built-STi-Stage-1-Short-Block_p_329.html

These prices don't seem that bad, however after adding gasket kits, oil pump, timing belt, head studs, turbo, fuel pump, injectors and engine builders time(or yours) the price jumps to $3500 to $4500+

Great links to built engines
http://forums.nasioc.com/forums/showthread.php?t=1431376

HP to weight ratio = 1/4 mile times Calculator, keep in mind this is ideal conditions. You will be slower. What is "Fast Enough?"
https://robrobinette.com/et.htm

Bottom line, go with the OEM STi or the stage 1, you don't need more. From there I would look at you budget and figure out whether or not to go the extra mile for STi heads. If you drive it a lot and want to get it done once and forget it, I would go STi OEM and keep it around 350WHP. Nothing wrong with the hybrid setup!

[STiPWRD]

Bill, I have the same hp and reliability goal as you. I went with the 18g turbo and the hybrid option: new EJ257 block with rebuilt and decked EJ205 wrx heads from an 02 donor. I installed forged JE pistons that are hybrid specific (JE part 291059) so the compression ratio is back in the safe range. The IAG block with forged pistons also looks like a good option for the cost. You can probably get by with just an OEM sti short block but the forged pistons are added insurance. I'm still breaking in the new motor so haven't really pushed it.

[Blwalker105]

Thanks all! I am leaning heavily toward the IAG short block/ hybrid setup. Really appreciate the input.

Bill

[titter]

another valid option is an EJ207 from a GDB STI. they aren't cheap, but its what i am considering for my future 818C.

i currently own a wrx wagon with a swapped JDM STI motor and its just amazing. its a spec-c motor from a GDBE4FH. stock internals are easily capable of 400 wheel horsepower for well over 100,000+ miles. the EJ207 is the best motor subaru ever made. it was used for WRC homologation so its engineered beyond imagination.

you will have a few extra wiring issues to deal with. you'll need to add AVCS wires to the main harness and also use the JDM ECU. other than that you will use the USDM harness like you would normally. it plugs directly into the jdm ecu. it is well worth the extra work. the GDBA and GDBB motors have forged pistons the GDBC, GDBD, and GDBE all have hypereutectic pistons. but both are still easily capable of impressive HP numbers for an oem engine. no need to replace the internals. you will easily hit 360whp on a stock EJ207 with a HTA71 and your powerband will be immense... the EJ207 revs to 8000rpm in stock form and with AVCS you'll be seeing power from 3500rpm all the way to the 8k redline.

[Blwalker105]

Thanks, titter, I hadn't considered that option.

[GoDadGo]

1. Fly down to Boca, way down there in Florida.
2. Buy a low mileage FWD Cadillac with a Northstar. (They Are Plentiful, In Great Condition & Inexpensive)
3. Yank the drive train by pulling the cradle so you don't disturb anything.
4. Break out the Plasma Cutter and Mig Gun and fit that Northstar into your 818 side saddle style like the old Ferraris.
5. At 275-300 HP you get a 4 valve per cylinder VVT V-8 that is designed to push a 4,500 pound Grand-Maw Mobile
6. While most of you won't like my idea (99.5% I'm Estimating) I've seen a Northstar stuffed in a Fiero GT and man does that thing scoot.
7. How quick it would be in a 818 would be totally insane!
8. Understand That This Is Just A Point Of View From This Dark Side Chevy Guy!

https://youtu.be/3f1Q4aS5SG4
https://youtu.be/UJwM5godh88

[frankc5r]

1. Fly down to Boca, way down there in Florida.
2. Buy a low mileage FWD Cadillac with a Northstar. (They Are Plentiful, In Great Condition & Inexpensive)
3. Yank the drive train by pulling the cradle so you don't disturb anything.
4. Break out the Plasma Cutter and Mig Gun and fit that Northstar into your 818 side saddle style like the old Ferraris.
5. At 275-300 HP you get a 4 valve per cylinder VVT V-8 that is designed to push a 4,500 pound Grand-Maw Mobile
6. While most of you won't like my idea (99.5% I'm Estimating) I've seen a Northstar stuffed in a Fiero GT and man does that thing scoot.
7. How quick it would be in a 818 would be totally insane!
8. Understand That This Is Just A Point Of View From This Dark Side Chevy Guy!

https://youtu.be/3f1Q4aS5SG4
https://youtu.be/UJwM5godh88

OK, I did it years ago with a 65 Corvair.60067

[GoDadGo]

OK, I did it years ago with a 65 Corvair.60067

Your My Hero Mr. Frank!
Now that is 100% Cool!