Subaru engine question

[BJ_buggyfab]

Looking at buying a engine package out of a rail. 
Guy has all the build sheets from Outfront. 
 Stock Sti internals 2.5

low boost 8-10 external WG

He says it was tuned on pump gas @310hp

 Now I was told can’t get 300+hp on pump?  Does this engine need race fuel? 
 John@outfront  sound right to you?

 

[sandeeevil]

On Outfront's dyno that combination would make 200 hp at tires on pump(91)

 

[FIREMAN]

Maybe 300hp at the crank. But not 300 to the wheels on John’s Dyno.  

 

[BJ_buggyfab]

Maybe 300hp at the crank. But not 300 to the wheels on John’s Dyno.  

I’d say that’s correct. 300 at crank. The concern is John told me I cannot get this hp on pump gas? Now this one for sale is saying that was John tuned it for? 

 

[Grease Monkey]

Everyone tends to promote a higher HP on engines for sale. 

If you've talked with John then go with what he says. 

If you want more hp, have John retune for race gas or e85. Then you know what you've got. 

 

[DeepBusch69]

Mine used to run pump gas when I only had 8 lbs boost.  Was told it was around 280 HP (thru Outfront).  When I went to 10 lbs boost, it was a new tune on the computer and race fuel,  330 HP.  

 

[BJ_buggyfab]

Everyone tends to promote a higher HP on engines for sale. 

If you've talked with John then go with what he says. 

If you want more hp, have John retune for race gas or e85. Then you know what you've got. 

I’m not questioning the hp number. I’m questioning what fuel used to achieve this reliability?

 

[BJ_buggyfab]

Mine used to run pump gas when I only had 8 lbs boost.  Was told it was around 280 HP (thru Outfront).  When I went to 10 lbs boost, it was a new tune on the computer and race fuel,  330 HP.  

This is what I’m thinking too

 

[Punchdrunk Monkey]

To me the "HP at the crank" numbers are BS. So Joe Blow has a dyno pull and it puts down 280, shows on the graph. But then he claims "350 HP" because it's more at the crank. How does he know what the number really is?? He doesn't. I've heard 20% loss, 30% loss through the drivetrain. Even that is a guess. I had a 2.5 (full) STi motor, on pump gas, that put down 411HP at the wheels. I had a dyno sheet to prove it. But I know there is no F@%&ing way that motor was truly 411 HP. That same motor would be in the high 200's/low 300's on Johns dyno. That's a 25% variance. So even a dyno sheet isn't always the truth. 

Now go drive the car......smash the gas pedal.........the smile on your face is the real proof  

 

[MWB]

To me the "HP at the crank" numbers are BS. So Joe Blow has a dyno pull and it puts down 280, shows on the graph. But then he claims "350 HP" because it's more at the crank. How does he know what the number really is?? He doesn't. I've heard 20% loss, 30% loss through the drivetrain. Even that is a guess. I had a 2.5 (full) STi motor, on pump gas, that put down 411HP at the wheels. I had a dyno sheet to prove it. But I know there is no F@%&ing way that motor was truly 411 HP. That same motor would be in the high 200's/low 300's on Johns dyno. That's a 25% variance. So even a dyno sheet isn't always the truth. 

Now go drive the car......smash the gas pedal.........the smile on your face is the real proof  

A good friend of mine started racing Mini Sprints a few years back.  The rules required him to get it dyno'd each year to prove he was with in spec.  He had grown up with one of the approved Dyno's  owners/ tech's.  It always amazed my buddy that no matter what he did to his engine each off season he always made just under the max HP allowed.  

 

[BJ_buggyfab]

To me the "HP at the crank" numbers are BS. So Joe Blow has a dyno pull and it puts down 280, shows on the graph. But then he claims "350 HP" because it's more at the crank. How does he know what the number really is?? He doesn't. I've heard 20% loss, 30% loss through the drivetrain. Even that is a guess. I had a 2.5 (full) STi motor, on pump gas, that put down 411HP at the wheels. I had a dyno sheet to prove it. But I know there is no F@%&ing way that motor was truly 411 HP. That same motor would be in the high 200's/low 300's on Johns dyno. That's a 25% variance. So even a dyno sheet isn't always the truth. 

Now go drive the car......smash the gas pedal.........the smile on your face is the real proof  

That’s great! Only what fuel do I run? I’ve blown up motors before on the wrong fuel. Considering we are talking John built AND tuned I think hp numbers can be accurate but on what fuel?

 

[Punchdrunk Monkey]

That’s great! Only what fuel do I run? I’ve blown up motors before on the wrong fuel. Considering we are talking John built AND tuned I think hp numbers can be accurate but on what fuel?

Mine was STi and same boost. I ran 91 pump gas. I was running the stock ECU because it had drive by wire.

 

[BJ_buggyfab]

Mine was STi and same boost. I ran 91 pump gas. I was running the stock ECU because it had drive by wire.

Ok. Makes sense. That cannot be done on most stand alone ecu’s Missing too many sensors to allow reliable use. No knock , IAT or even 02s sensors on most. Nothing to catch it if air temp is too high or poor fuel one time. 
 

my current set up uses 4 sensors 

map, crank/ cam and throttle 

very stripped down electronics 
 

 

[Punchdrunk Monkey]

Mine was stripped down too. Garage Tuning did the original tune to remove all the sensors/smog. I had the same sensors as you but also had a Mass Airflow in the throttle body. This had to stay for the drive by wire. 

 

[Rockwood]

I’d say that’s correct. 300 at crank. The concern is John told me I cannot get this hp on pump gas? Now this one for sale is saying that was John tuned it for? 

Why not?  Stock STIs breathing through street exhaust, street intakes and cats (pre and post turbo) make SAE-certified 305-310hp tuned to prevent Joe Schmoe Public from blowing it up with a top mount intercooler in rush hour traffic with an enclosed engine bay for 100k miles...  I know guys that have tracked their STis all day long without exploding, and that's going to be harder than 99% of dune runs on a motor.

 

[John@Outfront]

the answer to your question lies in the compression ratio.  if its pump gas then my recommendation is 8.3 to 1 for pump gas at 8psi nets 280 at the engine.  just cause you have an sti block doesnt mean it has 8.3 to 1 compression.  all sti motors had head chambers in the 55-57cc  i dont know what heads you have but pretty sure they are not an sti head.  the non turbo heads had cc's in the 46-51 cc's  to add more there are two sti factory blocks  one with 22.5 cc piston dish and the other a 24cc piston.  then there are head gaskets ranging from .027" to .060"    so you tell me the piston dish, the heads and the gasket thickness and i could get close to telling you if its a pump gas possibility

Now to answer Rockwoods question is that a factory ecu is hands down more sophisticated then a standalone and has knock control and air temp comps for ignition timing. i can push an sti around my shop with just me, i couldnt push a sand car 1 foot by myself in the sand. besides that the intercooler sees 60 MPH winds over it and the load on the motor at 60 is not even close to a 30mph drive thought the dunes with an intercooler also only getting 30 mph winds if its lucky and not obstructed.  im am conservative when pump gas is involved.  have i done pump gas over 300hp at the crank--yes but i need to know more about the driver, intended abuse, car weight, intercooler placement and cooling etc

 

[John@Outfront]

one more note:  the sti heads are better flow too,  but much more expensive so using a non turbo head is the norm, lending itself to more reason to not hit the 305-310 SAE factory hp numbers.  Stock cast pistons in a stock sti are the weak link and have ringland failures all the time.  tracking a stock motor Cleary would not be making it 100k miles.  

i could build a 400 hp motor on pump gas if you want, it may last for a few pulls but i can do it if "you" want!

 

[BJ_buggyfab]

the answer to your question lies in the compression ratio.  if its pump gas then my recommendation is 8.3 to 1 for pump gas at 8psi nets 280 at the engine.  just cause you have an sti block doesnt mean it has 8.3 to 1 compression.  all sti motors had head chambers in the 55-57cc  i dont know what heads you have but pretty sure they are not an sti head.  the non turbo heads had cc's in the 46-51 cc's  to add more there are two sti factory blocks  one with 22.5 cc piston dish and the other a 24cc piston.  then there are head gaskets ranging from .027" to .060"    so you tell me the piston dish, the heads and the gasket thickness and i could get close to telling you if its a pump gas possibility

Now to answer Rockwoods question is that a factory ecu is hands down more sophisticated then a standalone and has knock control and air temp comps for ignition timing. i can push an sti around my shop with just me, i couldnt push a sand car 1 foot by myself in the sand. besides that the intercooler sees 60 MPH winds over it and the load on the motor at 60 is not even close to a 30mph drive thought the dunes with an intercooler also only getting 30 mph winds if its lucky and not obstructed.  im am conservative when pump gas is involved.  have i done pump gas over 300hp at the crank--yes but i need to know more about the driver, intended abuse, car weight, intercooler placement and cooling etc

Here’s the engine.  Papers show stock sti block and pistons . Invoice does not state what heads are on it. 

 

[John@Outfront]

that motor was not originally built by me.  not my intercooler and never sold a motor with the stock red intake.  it has my fuel rails is all i can see.   the heads are 46 cc version so with 22.5 ccs dish from a stock sti and 46cc heads it would be hard to get to 8.3  even with the thickest .060" gasket  i can do the math on Monday  but this OEM shortblock generally had heads with 55 cc's.  9cc's is a huge difference