[wiseman]

Thers a member of our PCA club that has a 2004 Boxter S. He has a Borla cat back on and has touted that his car is pushing 300HP at the Flywheel. The car was advertised to have 258 HP from the factory I believe. He just had a Dyno run done and posted on You Tube and ultimately our PCA site. The results were 248HP in 4th gear at 110 MPH, 213 Ft. lbs. of torque for a "Total" of 292.8 HP "At the flywheel". Strange the Dyno didn't show an RPM reading. Anyway, I thought the automotive industry had adopted "SAE Net" horsepower ratings which were always at the rear wheels with all attachments hooked up, (PS.,A/C etc). So when Porsche publishes HP ratings............which is it? Flywheel or Rear Wheel?
Inquireing minds want to know.

Partial Post: Please Login or Register to read the full post.

[Monstrous4Banger]

Dynos, are usually at the wheels, I dont know of a dyno that measures at the flywheel, unless its an engine dyno, and you take the engine out. You have to calculate for drivetrain loss. Porsche rates at the flywheel. AFAIK, they dyno it on a stand before they go into the cars.

Partial Post: Please Login or Register to read the full post.

[flash]

SAE published ratings (like in the owner's manual or a magazine) are at the flywheel

this requires an engine dyno though - different animal than you normally see at a tuner shop

Partial Post: Please Login or Register to read the full post.

[kwikt]

WOW.... Almost 50hp gain for a cat back Borla. I'm sold!!!!

Partial Post: Please Login or Register to read the full post.

[benspeeder]

We estimate that a Porsche with transaxle will lose about 15% through the driveline - most cars lose between 15-20% through the driveline.

Making 248 RWHP would put him at 285 at the crank. That's a 27 hp gain at the crank which is dang good and consistent with a 10% free flow exhaust gain

Partial Post: Please Login or Register to read the full post.

[Fox944]

there is no way he gained nearly 30HP from a cat-back exhaust. There is more to that story...but yea.

Partial Post: Please Login or Register to read the full post.

[Monstrous4Banger]

Yeah fox944, thats what I was thinking. 30ish on a normally aspirated engine, with just a cat back? Turbo motor I could believe that, but even then you have to delete the cat really to pull those kind of numbers. Back pressure is a b!tch.

Partial Post: Please Login or Register to read the full post.

[wiseman]

<b>Making 248 RWHP would put him at 285 at the crank. That's a 27 hp gain at the crank which is dang good and consistent with a 10% free flow exhaust gain </b><i></i>

I should have said he has Borla headers and a Cat back. I think they advertise from a 7-15% gain, so at the mid point of 11% increase it would be 286hp..........so I guess he could be at 292 at the flywheel.
Thanks guys.

Partial Post: Please Login or Register to read the full post.

[94SilverCab]

That's definately a different story. No one claims to make any significant horsepower from a cat back alone...perhaps 1-2 HP and the advantage of weigh loss of about 33 pounds. The header on the other hand does imporve performance, so it doesn't surprise me that he had gains. Not sure what RS Barn claims are on HP from the addition of the header, it also come with a new chip and mine came with a bunch of other goodies at the same time [img]style_emoticons/<#EMO_DIR#>/biggrin.gif[/img]

Regards,

Jay

Partial Post: Please Login or Register to read the full post.

[smshirk]

I had my Boxster engine upgraded to a 3.6 liter by Jake Raby. The upgrade consisted of the following;



Standard Features -OE Mechanical Parts



o Reconditioned crankshaft

o Upgraded connecting rod bolts

o New main and rod bearing inserts

o Porsche updated gaskets and oil seals

o Blueprinted OE oil pump

o Modified 3.2 cylinder heads using all new and upgraded valves and components.

o Standard reground camshafts



Standard Features – Assembly/Tuning/Labor



o Level II prep and engine assembly

o Intermediate level dynamic balance (with index)

o Standard Tuning

o Standard Dynamometer Optimization



All items inclusive in the Performer engine package base price



Standard Features – Upgrade- Mechanical



o Ultra high performance LN Engineering “Nickies” Big Bore cylinders in 99mm.

o Custom JE Forged pistons with lightweight pins and low tension rings.

o Ultra-Duty Billet Chromoly Intermediate shaft bearing

with modified intermediate shaft

o Smooth-Flow spin on oil filter adaptor



Options –Mechaqnical-Parts- Customer chosen



o LN Engineering Billet Chromoly Connecting Rods

o Low temperature actuated thermostat update

o Race level Dynamic Balancing (with index)

o Cryogenic enhancement of valve train components

o Cold Air intake system

o Lightweight aluminum racing flywheel

o Custom Header system

o Aftermarket muffler

o Performance engine and transaxle mounts



The net HP and torque at the wheels is ~295 +/- and pretty

flat across the curve. Note that at the very end I purchased after market exhaust.

I ended up putting the factory muffler back on because after

much dyno testing on various well known but unnamed after market units, the increased HP was negligible and only in the upper range. This was done prior

to the engine work as well. The drone just wasn't worth a couple of HP/

I did opt for high torque output rather than max HP, but with

compression at 12.75/1 there just isn't a lot more HP available

from a Boxster engine without forced induction.

Partial Post: Please Login or Register to read the full post.

[benspeeder]

I've thought about doing a motor swap in my '98 Boxster - do you mind me asking what it cost?



Thanks

Partial Post: Please Login or Register to read the full post.

[smshirk]

I hate to say, but we're all friends here I guess. About 18k start to finish. I did a lot of things that didn't have to be done. You could achieve the same end results power wise without using all the reliability parts I used i.e rods, nickie cylinders,forged pistons. The IMS shaft is the big improvement over stock design, as well as the oil filter relocation and lower temp thermostat. My eye was toward longevity and someday perhaps who knows what I might do to it. It can handle most anything, but the compression is too high for forced induction as it is now. So now the engine is worth more than the car.

Partial Post: Please Login or Register to read the full post.