qikqbn

Kudos to you for doing this right and using oem performance parts. I know this is not cheap, but one great way to upgrade your 997 into something very special. This is more or less exactly what I plan on doing to my 997.1 when I think it is time to refresh and rebuild. Possibly around the 100k mark, I am at 77k now. I absolutely love my car and have no plans on selling it. The best TLC you could give to a long time faithful ride is a fresh engine rebuild done right. I have seen these builds putting closer to 380 down at the wheels, which would be between 440 hp - 450 hp. The Torque is not turbo torque, but for NA motors, the torque is a nice bump with the 4.0. Can't wait to see it all done!!

Ps... Correction... the dyno reading I saw showing 384, may in fact be corrected for at the crank... If so, then I was way off.... Still, looking forward to seeing your results and hoping to see anywhere from 35-45 hp bump, but lot's of torque as well.

vern1

May i ask where you have seen a 4L build putting down 440-450 HP?

Cheers

Hammerman501

qikqbn

I saw this vid many years ago. I was remembering this video that showed a dyno result of 384 hp and they had a follow up car in another vid of 379 hp dyno. Based on dyno results that would equal 440-450 hp...
Here is the rub, based on seeing the dyno figures and assuming it was wheel horsepower that is where I had assumed the numbers.
Looks like they adjusted dyno to read crank Horsepower, which bums me out.

After checking out their website they are advertising their kit to give
2008 Porsche 997S
Engine M97.01 3.8L

RSP Conversion 4.0L
Max HP 384-hp@6400
Max Torque 343 ft/lbs@4600

Modifications
• Complete engine rebuild & displacement upgrade from 3.8L to 4.0L.
• Stainless steel exhaust.
• High flow sport catalyst converter.
• BMC high flow air filter.
• RSP custom dyno tune,re-programming OEM DME
• Emission test approved.

The 384 Hp , if that is indeed at the crank, seems very low to me considering the mods. A 200 cc bump should be good for at least 40-50 hp if done right.
The Torque numbers are what impresses me, but was hoping for a higher hp number considering what other Porsche 4.0 liters are putting out from factory.

srcn

A factory X51 car makes 381bhp. You're adding X51 hardware and then some.
I'd say don't worry about it, you should be making well over 400bhp.

Love the car, BTW. I was thinking along the same lines for visual upgrades. My factory X51 car may get a 4L upgrade some day too.

Hammerman501

vern1

Thanks, interesting. That does seem conservative but a dyno is a dyno. Will be interesting to see what comes out of this build. Will get mine dynod at some point just out of curiosity.

Hammerman501

DrJordan1911

Im following this build, I've done a 4.0L bore as well...384hp at the crank is too low from what I can tell as well... with those mods. Im betting you'll end up 420ish

vern1

If the M97 is the epitome of engines then Porsche is in deep crap!! People are doing these type of upgrades mostly because their engines blew up, not because they want to. Combined with the IMS issue i would consider these engines to be a very poor performance from Porsche

vern1

Dont think i have seen anyone with a 4L rebuild who has done a dyno (other than the one listed above), myself included. Would be nice to start seeing some empirical evidence of what this mod actually produces.

mjsporsche

I appreciate where you are coming from when you had to spend upwards of $30k to replace an engine (with a great high performance upgrade). The percentages with IMS problems before the upgraded by Porsche is still very low. But when you are in the low percentage group, it still stings. Frequent oil changes, keeping the revs in check when the engine (and outside temps) are cold, and not hitting redlines frequently does manage the risks.

vern1

And it frequently doesnt manage the risk. I have heard this before as people seem to take some kind of false comfort in this when they fire up the car but i did all these things (as have others) and it made no difference. I have also heard all these rationalizations before (its a low percentage group etc) but the fact is, these are serious engineering failures. Am not sure if you are defending the M97 engine or not?

Regardless, from my perspective, to call the M97 the epitome of NA Porsche engines is laughable. The 9A1 in the 997.2 appears to be a much better engine if you are going to pick a 997. But no way the M97

I am looking forward to seeing how this build turns out but as i said, not many people voluntarily go down this path

Fined

+1

I've now heard it all, here on Rennlist. Looking forward to seeing how 9A2 stacks up vs 9A1. M97 is a low point, hopefully the defining low point in relatively modern Porsche engine design.

latonnelier

This looks like a great build. BTW, what is the rear bumper that's on the car now? That's something like what I have been thinking about for my '06 C2S
I really appreciate going with no wing--I'm not against them per se, just seems that for what your doing the bare rear end is a great choice.
G