ehall

That is the question. It applies to a street car application only. That means that the engine needs to be durable enough to drive daily, we'll say 10k per year, and last 100k miles, before needing a rebuild. This assumes proper maintenance, and reasonable boost levels.
I ask because I'm being forced to do a rebuild over the next 6 months or so, and need to plan a budget around my performance goals. The primary goal is to create acceleration performance on par with the best of the top "super cars" of today. Obviously that's a pretty broad interpretation, as the car will always lack the displacement of the majority of those cars, but for a street car, acceleration is usually more of a priority than top end capability.

Your input will help me make a final decision between a couple of different ideas that I am debating at the moment. Thaks in advance for your input. I really look forward to hearing from some of you larger displacement guys, as well as the really high output 2.5 guys.

sweanders

I recommend a couple of DE's and a suspension upgrade. If you haven't done it already you will realise that 400 rwhp won't do you any good without grip or skill.

Otherwise you might need to get a bigger displacement than 2.5 liter for 400 rwhp on pump gas.

ehall

"I recommend a couple of DE's and a suspension upgrade. If you haven't done it already you will realise that 400 rwhp won't do you any good without grip or skill. "

Thanks. Now back to the topic.

special tool

yeah man - you are heading into the crazy zone at around 370 RWHP with 275 rear tires - no grip at all.
At around 400-425 RWHP you will spin the factory clutch like a dradle at Hanukah
Other than that, you know what I would say to buy...

J Chen

I agree Sweanders, suspension & brake pads upgrade
was the very first thing I did before I started to upgrade
the rest.

sweanders

No need to ignore my recommendations, with a worn or stock suspension you will not get the power down and it can get really interesting. Make sure you have a diff brake as well.

PorscheDoc

Chips, turbo, 3" exhaust from the turbo back, wastegate, MAP, Intake, Cam.....oh wait you said cost effective

ehall

Guys, I've done a good bit of suspension stuff. More will be done first. I don't have a choice about an upcoming rebuild, and I'd like to do it one time. Therefore, I'm looking for some theories, and tried and true ideas, to accomplish the goal. I already know this other stuff. I'm a 36 year old veteran of one war and numerous excursions. I'm not a 20 year old who wants to drag race.
As far as getting power down, that is a separate issue, of which I am aware. I'll not only need a ton more clutch, but I'll need to get a new LSD, as my car is without one. I would really like to confine this to engine build out/cost effectiveness issues. I do sincerely appreciate the input, but we've had a large number of flame fests lately, so I'm hoping to try to keep things pretty close to topic. Thanks again E

special tool

Start wth the SMT6 - it turns your Motronic into a standalone. Yes, it does full timing including advance (no, there is no advance built into the chip) I can't imagine a better place to start.

BoostGuy951

Vitesse Stage 2 or 3. Thats my reccomendation.

David Floyd

Special Tool,

Make a list of what it took for you to reach 400

I don't think my way was very cost effective.

I agree with the above Vitesse stage 3 and SMT 6 is a good start

pk951

Take a look at My Swiss's car that will give you some idea what it takes to make that kind of hp.

On pump gas 400 rwhp for get it, unless you are running a 3.2 liter.

hmd

ehall,

I am not sure about 400+ but for streetability I would go 2.7 bore while you have to rebuild the engine anyway plus a Vitesse kit. At a guess this would get you 350-400 rwhp on pump gas running conservative boost level for reliability.

fast951

For a street car, the less lag you have the better.. Since it's a street car and you are not concerned about rules (as racers are). I would go with a large displacement engine. A 3.0 or 3.1l will be on top of my list. (you can keep the 2.5l crank and get 2.7 or 2.8l), but the longer stroke makes it a joy for a street car. The area under the curve is broader with the larger engines.
A 2.5l will deliver 400rwhp, and can be driven on a daily basis.. However if you are rebuilding anyway, the larger displacement might cost a bit more up front but well worth it.
The miles you can go between rebuilds depends on how you drive it... A stock 951 driven hard 100% of the time will require a rebuild before 100K miles.. Things simply wear out...
There is no reason a well built engine wouldn't last 100K miles even at 400rwhp. Of course, on the street you will rarely use the 400rwhp... Based on my experience with customers, most are happy with 320-350rwhp on a daily basis.. More than that and it becomes a traction issue.. Of course, most customers do exercise all the ponies every now and then.

ehall

Great stuff so far.
David, If I recall correctly, it was someone else's fault that yours wasn't cost effective. That had to suck.
Fast951, you're right, I won't really utilize the power very oftern, but I don't intend to sell this car, so I don't want to grow out of it. That's why the goal is where it is. It ridiculously high, but as you said, since I have to do it anyway, I want to really aim high. This post is not so much about dollars per se, as it is about the ways to skin the cat, that perhaps I haven't considered. So thanks to all, so far.