123quattro

Direct injection will get you about 3%. Part of that is from having a higher compression ratio, and part of that is being able to run more spark advance. VVT can make a huge difference. It doesn't get you any more power, but regains midrange torque you lose to get good peak hp. Even on an engine making ~60hp/L it will get you something like 10% more torque down low.

ITBs make peak hp, but are really a pain to tune (especially on something trying to meet current emissions standards). They also give up a lot of midrange torque. New intake manifolds flow exceptionally well, so unless you are running 7500+ rpm it doesn't really matter. New exhaust also perform very well vs old stuff. Take for instance the manifolds on a 7L LS7 engine. They only make about 5 hp less than long tube headers on a stock engine. That's a 1% power improvement for long tubes. Putting long tubes on a 928 engine gets you about 10% more power. Combine that with new heads that flow as good with stock castings as fully ported heads from 10 years ago and new engines make a lot of power.

450hp out of a 5L engine is about the magic number. You can go higher than that, but you'll lose torque and reliability. I hate to say it but the Ford 5L is a very good engine. It will be even better when they bring out the DI variant in a year or two.

GregBBRD

Correct.

RKD in OKC

The stock Ford GT 5 liter makes 412. The High Output makes 444. The stated changes that make it high output are boxed runner intake, rods, high lift cams, and quad exhaust.

Back in 2001 when I took my 90GT to a dyno used by lots of Ford 5 liter Mustang guys, they were very impressed with the 310 rwhp run. Dyno operator (mustang guy) said they were spending a lot of money to get that out of their Ford 5 liters.

andy-gts

I have ross pistons, gt rods and polished taylor drilled crank just waiting for Hans to say yes to the deal of a lifetime(for me). that with itb and cams and Greg's handiwork and you could have 100 hp per liter and 7500 rpm...


wow

brutus

Gt 3 911s are quite easy to drive just quite fast. It is a fully warrantied smog legal street car so 500 Hp out of 4 liters is doable by Porsche with todays technology. Worth mentioning that peak torque is at about 5,800 RPM max power at 8,200. Want more hosepower out of the same displacement just make it able to spin higher with more camshaft ! Nascar engines have proven that for years hitting nearly 10,000 RPM on some tracks but with a average service life of maybe 600 miles .

Markmandude

It is fairly easy and cheap to get 300 rwhp put of a ford 5 liter. Heads/cam/intake will do it and you can gets heads and intake from used from other stock ford engines for less than 1000. cams less than 500. You can also slap a small supercharger on for less than 2000 for the full kit, not including labor like I did and get 300 rwhp. You can get larger supercharger for 3500 with intercooler and get 350 rwhp. Add heads cam intake and supercharger together and you can easily have well over 400 rwhp for less than 5000 in parts.

FredR

Thanks for the interesting posts chaps. Nothing too surprising in there. The 928 is not really suited to being a high revving screamer and to be fair, I have not really seen anyone try to make it one. you have to be pretty committed to invest money in the engine that amounts to a much and maybe ore than the residual value in stock condition knowing that if you need to sell you willinvariably lose most of the increment you invested in the motor.

To those like Andy who go down the extended power route I take my hat off to you all and long may you enjoy the fruit of your efforts.

Regards

Fred

Markmandude

I think any car you invest a lot of money in moddifying you have to assume you are going to lose most of the money, if not all the money when you sell.

RKD in OKC

Back when I dynoed the 90GT the Mustang guys were blowing head gaskets like crazy with those "cheap" power adders. Seems tuning has gotten much better in the last 10 years.

Markmandude

I put my supercharger on in 02 on a 91 5.0 with 60k miles on the stock motor. I now have 135k miles with the same stock motor and supercharger. Engine has never even had the stock heads off. I dynoed at 299.6 rwhp and 355.4 lbs tq. Only mod I had at the time was cat back exhaust.

Of course if those Mustang guys are pushing high boost and not doing the other necessary mods they are going to have problems. You don't really need high boost to get to 400 rwhp with heads/cam/intake.

hacker-pschorr

Today?? Ferrari introduced a 3.5 liter V8 back in 1995 that put out 380bhp.
Chevrolet has the "Black Widow" ZR-1 with 475-500bhp. Politics similar to what held back the 928 kept that version from being a regular production model.

Porsche could have released a 5 liter V8 with 500bhp back in 1987 if they wanted to. Same way the Boxster "only" had 201hp when released and later the S 250. It wasn't like they didn't know how to make the extra ponies in 1996. They had a list of reasons why they only wanted 201 with the introduction model.
Fact is, horrible sales and the decision not to ax the 911 will forever be the reason (the big ones anyway) we ended up with the power we have.

martinss

I offer the Porsche Carrera GT as evidence of something exceeding the then concurrent 911 (2004-2006). Provided you charge a lot more money you can offer a V engine with more power w/o threatening the 911 positioning: 5.7 litre V10 engine producing 604 hp. That said, it is interesting they used the name Carrera as if it was related to the flat-6 cars.

JWise

I don't know much about the new Mustang engine, but it sure looks good under the hood:

Markmandude

Amazing! It doesn't have a giant plastic cover over the entire engine like so many other new cars.

Ispeed

Our S4/GTS engine management is barely able to compute what is going on on a stock 928...