MrBean

I'm still around Have sold the F6 Ute long ago, after acquiring Permanent Residence, we decided to build a house....you know how that goes...I recently got myself one of the last new XR8 FGX's....fun car, will start some mods on it soon. Currently still stock. PS: Won't you believe it, back then I actually did buy the Skyline IRS rear suspension for the UTE, it's still lying in my garage.... Cheers, Beano

At least with V8's, if we keep rpm's below 7krpm, we should not have to many issues with valve-train. Plus, the bottom end will be pretty comfy at those rpm levels Of course, on any engine, once you go past 7krpm, valvesprings become a big problem - they fatigue like crazy, especially after 7.5k.....so good to keep 7k and below...... @ 01txr: Oops, looking at that rod, seems you made to much torque low down in the rpm scale.... what was your tune like? Either that, or possibly detonation. Of course, having a soft torque-curve at lower rpm's always a good thing, for any engine....

Gotcha, Mate, then we're on the same page I still luv the Ford I6 though, a very balsy engine with the turbo, especially when enhanced with a few goodies.....just a pity about it's reliability at sustained higher rpm operation.....but, then again, we're not all race-drivers.... Good discussion going here, thanx all!

@ Winstor: I should probably make it clear that when I refer to inline 6, in this context I refer to our particular Ford inline 6. It is a shaker. It doesn't have counter-balance shafts, and cannot ref, unless you spent huge amounts on steel (with Malory heavy-metal inserts) crankshaft, 4-bolt caps, et al. And here is the problem -> a huge amount of torque if tuned with 350+rwkw, and a narrow rpm band.....resulting in an unreliable bottom end. It will not sustain high-rpm operation for lengthy periods.....you will most likely shear the crank in half, loose the harmonic balancer, or worse, drop the crank in the sump. For that same money, well, you know the answer. You would probably get a very decent 7k-8k rpm Coyote....with not much more I would venture than better valve-train. But, all conjecture on my side, take it as you wish. As so many guys here have mentioned, we are really fortunate to have the choice between 6 and 8's in Oz.

Tab' date=' we should tell those skinny boys to put some meat on them bones At 107kgs, I am definately not sliding around in the leathers. Ok, I know I sold the UTE, but the G6E has leather..... I know the big Jimmy Roots blowers can take up to 30% to get keep them going at full boost. I wuld reckon you'd still loose 20-25% on the units in use on the Miami. These setups do desperately need an intercooler.....as heatsoak does effect them.

and Well, it is simple, really - the V8, by nature, is a smoother engine, and will rev higher than the inline 6 which is a shaker. The way we drive, the inline 6 should last, but, it will not withstand high rpm, at high torque-levels, for long - it is a shaker, and the bearing caps tend to walk all over the place, and the narrow rpm band (due to resonance frequencies at higher rpm) doesn't do much to alleviate the situation at higher torque levels. Whilst the inline 6 is a quick beast, (mine had around 378rwkw at it's best, I would venture to say that, with twin turbos, the V8, and running around 15 psi boost, would yield a 10L engine, as engine capacity is (approximately) doubled at 1 atmosphere pressure - the inline 6, at 15 psi boost, will only be an 8.0L engine - or, to be more specific, the engines will be developing as much torque as their naturally aspirated cousins of 10.0- and 8.0L respectively. Please take note that I compare apples with apples here, ie turbo vs turbo,and, I would expect that, with a steel bottom end, even though the V8 has not "proven" itself according to a few guys here, it will simply kill the inline 6 in similar configuration. I am a V8 fanboy, but, let me say this to: I had a test drive in the Etheridge Ford Ringwood GT last week, and was very disappointed - and, going by gut-feel, I would reckon it is on par with how my stock F6 UTE performed off the floor, in sotck trim. But, I would also say this - once we start playing with these boys in apples->apples setups, no match. A turbo V8 at the same boost levels will always make more, and reliably so, power than the comparable inline 6. No flaming guys, just my experience on eights vs sixes.

At the risk of totally going off-topic, for me it is a simple decision to have turbos over positive displacement pumps - fuel economy if you want it But, as you rightly mention, space is a problem with the V8..... Soz for off-topic,guys.....

Cannot agree more, Mate. That would have been ideal.

It is just the opposite, Mate. Turbos' are way better at higher RPM (remember, rule of thumb, turbo output pressure quadruples with doubling in speed), and blowers, being positive displacement pumps, are better (immediate) torque deliver off the bat. I would expect a turbo 6, at around 16psi boost, to kill the V8 at around 10psi boost on top-end. Total engine capacities should be the same, but turbo engine will deliver more torque simply due to higher adiabatic efficiency. Or something such. I would expect the V8 engine to be stronger off the line, and, all else equal, should be the quicker car down the 1/4 - while the turbo 6 stronger at top-end. If we consider identical rwkw's, that is. Luv the new V8, and would like to one day slot twin turbos on one -- then no T6 will get close

Heya Spiro, Point well taken Thanx. Yep, you're spot-on, I have quite good experience with Ford small-block V8's, having put together pretty powerful beasts back in the Republic up to the mid-90's - but I'm not that familiar with the Aussie 6. I have no doubt they can rev, but only concern was for the reliability at high-rpm's....but, I am always ready to learn from someone more experienced, and, wrt this particular inline 6, that is from almost everyone! But, appreciate the work that blokes like you and others are putting in so us noobs can put together semi-decent street-performers - my current UTE is making a measley 370rwkw....sad, I know. One of these days I will start a 500rwkw built - no need for more power for my application though, even though I would probably opr for something that would be able to accommodate 1000-1200hp.... Will be in touch, and have a good one in Brisvegas.

Thanx Spiro, appreciated. Experience with V8's tells me that valvesprings tires very quickly at 7,500 rpm, where you can do approximately 400 1/4 mile runs at this speed, and then, once hitting 8k rpm, only about 50 runs at that speed. Don't know the dynamics of a more modern valve-train on the inline 6 though, but, of course, if you have a very customised crank, with Mallory slugs et al, and very well counter-balanced crank, you might have the harmonics sufficiently up in the rpm band to have a trouble-free bottom end at around 7,500rpm mark. But, running "all-day/every day" at these rpm-levels, well, let's say I would like to see that first. Again, proof is in the pudding, and I'm not flaming or anything such, just that it's going to cost an arm and leg to try and get any sort of reliability out of these engines at the levels you're talking. I don't believe it can be achieved with the heavy rods used in the 998 motor, as the heavy rods are just aggrevating the harmonics'problem in an engine already suffering of to small/light counterweights on the crank - maybe using super-expensive Titanium rods will get you there wrt harmonics, but, then again, not reliably so. I would luv to see the trends done on each bearing-cap with vibration-sensors mounted and captured at say, 20-30ms intervals If you don't mind, please share those you have with the 9k rpm engine. Have a good one, and talk later again.