SSbaby

No, you are correct, it's got grunt.

But we tend to overlook the important factors of engine design and just concentrate on power/torque, which is not the be all - end all of engine design. Please let me explain...

When Maclaren were after a engine for their F1 supercar, they had strict requirements in both power/torque, dimension and weight. Maclaren eventually settled on the BMW 6.1L V12, which didn't even have a flywheel! The long stroke 5.4 litre Ford donk weighs about 50% more than the LS7, which is around 220 lb! Imagine if the GT weighed that much less.

In regards to the Ford, I don't know who they are trying to fool if they believe they can ask for $160K+ for (what you termed) a "Rush Job" but as a consumer I would be totally pissed to find out that the Z06 perhaps took longer to develop... and that's without shortcuts (totally new LS7) and costs half. Obviously there must be a lot of wealthy people who aren't very fussy about value or development detail when it comes to the GT. The sleek looks of the GT (which looks sensational IMO) obviously helps here. But for my money, the Z06 is more the racer as it was based on the C5R.

Btw, any engine with Bore/Stroke relationship of 90.2x105.8 (mm) is obviously compromised.

Bob Cosby

I doubt too many Ford GT owners are worring about a Z06 being about as fast as their car for a lot less money. Could be wrong, but I'm doubting it. I'd suggest about the only folks that really care are those that are on these types of Forums and want to crow about their choice of car maker beating out someone else's choice of car maker.

As for the 5.4....the bore to stroke ratio is out of whack for a "performance motor" compared to what most folks think it should be, but that doesn't mean it can't perform. I know of one particular N/A 5.4L motor (332 cid) putting down well over 500 RWHP and spinning way to the north side of 8000 rpm using very modest cam profiles (4V heads don't need big lift/duration numbers). Though not a driver, it is streetable, and is very docile at idle.

That said....the LSx series engines are superior performance motors - no doubt about it.

SSbaby

Would the hugely undersquare bore/stroke ratio present durability problems? It might be capable of 8000rpm... but for how long? The piston speeds would be incredible at those revs. I doubt any engine with a stroke of 105.8mm would last very long at frequent high rpms.

muckz

$70000 in 1995 would cost $87091.88

Let's be a little more factual

Bob Cosby

The guy's name is Al Papitto. He's been racing it for 3 or 4 years now, though not on the exact same motor/parts. He has broken drivetrain parts such as valves, springs, and camshaft sprokets (mainly due to going where "no man has gone before" with these engines), pistons (putting the top ring too high - another experiment), and various drivetrain parts. He has never had a rod, bearing, crank, or piston failure due to rpm, and given the cid of the motor, it puts out pretty impressive power.

You are correct that piston speed is stupid fast.

RussStang

I could see it holding up in a drag car, but with a piston speed of roughly 5,500 fpm I can't see an engine holding up for that for that long on a road course where extended high rpms are necessary.

Bob Cosby

And that is quite possible. Then again, if the engine were built for a road course, I'm sure the powerband would have been adjusted for it, and the rpm range would likely be quite a bit lower.

Then again, it is all speculation, and neither of us know for sure.

RussStang

Well, if it was for a road course, I would be extremely inclined to believe that the powerband would be lowered for the sake of the engine, but then you are losing hp now as well. Either way, I am not really a fan of really undersquared engines like that.

Bob Cosby

No doubt higher rpm typically means higher HP, and thus lowering the rpm would mean lower HP.

Question: How many undersquared performance engines have you owned/raced? Is that the bases for your lack of being a fan?

RussStang

No, the basis of my opinion is how much more slowly undersquare engines have always seemed to rev to me, and the problem that when you have achieved a certain displacement with more stroke than bore, it is often a problem to feed that particular displacement engine the air it needs as RPM increase due to the smaller bore and the smaller valves that it entails. Not to mention that often with a stroke that is kept to sane levels the connecting rod can be made longer, keeping the piston dwelling longer in the combustion chamber at higher rpm and reducing thrust loading on the cylinder wall. Info I am sure you are well aware of, but many of the reasons I dislike undersquared engines. I am not ignorant to the fact that there are many undersquare engines that manage to rev well and make great power for their displacement, many Honda engines for example, but I suspect this has more to due with the lighter weight of the entire rotating assembly brought on by their smaller displacement.

SSbaby

The reason I mention durability is that we have Ford 5.4L DOHC engines here in the Falcon (iron block... I know, it's not the same engine)... anything over 6000rpm and the engines are history. I gather the alloy engine in the GT would be ridiculously expensive due to the need to bulletproof every perceived weak link.

That's the difference between the respective GM and Ford performance philosophies... GM make their engines simple, cheap and effective where Ford make theirs too expensive, under and over-engineered... and disappointingly not as good.

Sorry, don't mean to offend all you good Ford fans, here. But Ford are seriously lagging behind in engine development... they can't continue to use the 5.4L forever. The GT is a great car in need of a great engine. That's why I can't understand how they have buyers willing to pay above sticker price for the GT... as far as exotics go, you'd think they'd instead buy a Ferrari. Moot point anyways and good luck to Ford for their sales success with GT.

Bob Cosby

I cannot (and thus will not) argue that GM easily leads in the performance engine segment. The LSx is light, compact, powerful, and efficient. If it weren't for the LSx, the modulars might be put in higher regard (as they do pretty decent for what they are). However, "if" doesn't move a car, so that's a mute point.

I used to always say that my 99 Cobra would have been damn near perfect if it had come with a live axle and an LS1. I did pretty good with the DOHC 4.6 and really enjoyed it, but the LS1 was simply the better powerplant.

HAZ-Matt

Why didn't you swap an LS1 into the Cobra then?

Bob Cosby

LOL. The NMRA was pretty particular about making sure you had the right engine in your car before AND AFTER you raced.....don't think I could have convinced them that an LS1 had 4 valves per cylinder....

FutureZMan

amen