Lawsy

we have 15x10 convo pro wheels under the rear with 28x11.5x15 drag radials on them, we have been doing alot of these rear ends for customers oflate. Leme get this retarded american type of tyre marking strait... My guess is 15 inch rim, 11.5 inch wide, 28 inch total diameter.... If so, sweeeeet.... Can't wait to see the results.....

Power is the work done. Its the time it takes to push a certain weight over a certain distance in a certain period of time. Its a Force distance variable.... If you have a higher power average, then will go down the quarter in less time or with a higher MPH (if traction and transmission losses were 0, then you would always go faster and always have a lower ET with more power) than simply more torque..... If your car makes an average of 300kw at the treads between 4500rpm - 6000rpm with 700nm of torque at 3500rpm, but the person next door makes 330kw average between 5500 - 7000rpm, with only has 600nm of torque at 4000rpm, the person next door is going to slam you down the quarter, ever time, assuming traction isn't an issue (remember, these power figures are at the wheels, so transmission choice has no affect in this example). I have a whole theory thing behind it all if you wanna take a look at it.

Ohh I like the sound of that! So did I read that right, you have 380 (15in) slicks on the back? Sounds great, what work was done to get this? (if that is indeed what you have done... If not, my bad).

Good stuff, should look tops!

More information required!!! I nearly fell off my chair....

I'm just agreeing with everyone, they will look good with nice big brakes behind them with matching coloured calipers (to the car).

Its not a matter of breaking the limit... Its how quickly you can get to it.

Well.... A number of things need to be considered. The first thing is, not everything outside of the driveline needs to be altered, some things do, but you don't need to go redesigning the roof... Maybe a slight harden of the suspension to keep it a little more gelled, a bit of weight saved through, I dunno, a better constructed bonnet and boot, maybe a 20kg saving here or there, but that's about it. So, the entire driveline would need to be strengthened... Lets give it a nice round 700nm of torque, just to be sure.... Start from the front. Bigger, more efficient intercooler and radiator ..... Stronger Engine mounts. Stronger accessory belts to cope with the extra twist of the engine, heat and forces produced in this area. All the usual engine strenth stuff (rods, bolts, rings, pistons, bearings, springs, valves.... head bolts ). Either a larger sump or a high quality dry sump arrangement to hold a greater amount of oil. A more effective lube arrangement nonetheless... Stronger main end bearings, stronger crank, Higher quality flywheel, stronger drive shafts, stronger clutch/torque converter assembly. Then, stonger gearbox with cooler (Manuals don't really need one), stronger CV joints, higher quality balanced tail shafts, stronger diff with hydraulic lockup capability, maybe even a smart diff with some electronics connected, relaying to some form of stability control... Stronger axils, hubs, wheel bearings, and even stronger links in the IRS to be sure.... Of course, bigger brakes.... So that's just a start, just a glimps of what needs to be researched, feasability checked, tested and then implemented in order to up the grunt. And that's not even that detailed a list, there are so many things you could add at almost any point in that list that could possibly be a weak link with 700 odd nm of torque being shoved through....... Massive torque loads tend to break things that aren't directly related to the main driveline components, or should I say, massive torque tends to brake unexpected driveline components.... Its allot of work! And just to increase the strength of all that to cope with just a 200nm torque increase requires a serious amount of engineering, remembering that, they then need to over engineer all those components to be stronger yet again, by a fairly large percentage of the increased load.... I'll say it again, tts allota work!

I know, I came from no where with that one..... I was distracted on the phone and just entered it in without explaining myself.... lol, my bad

Well.... Cams cannot be seen from the outside... neither can injectors and the Edit... Cams + injectors + Edit = one happy XR8....

Ohhh and also Jeff, Craig has a copy of you showing off your 'driving skills' at the end of his street... ask him to post it up Rob... This is what I'm waiting for... PS wd glenn.

No offence, and I'm sure you know what you are on about, but it's just that everyone else seems to disagree with you... Most motoring magazines, who have plenty of engineering nouse behind them, seem to think that economy will improve as well as performance. And yes, it does matter if the revs drop less between each shift... Think about it, gears are a ratio. Gear ratios multiply the torque. If you can have a higher torque value at the rear wheels for the duration of the quarter mile, then you are going to have more force pushing you forward. This also equals a higher average horsepower applied over the quarter mile because the revs are always higher. Which brings me to my next point, when it comes to outright quarter mile times, its horsepower that does the trick... Horsepower is how much torque can be applied over time. Its the work done. So the the higher the average horsepower you can apply to the rear wheels over the entire quarter mile, the lower your ET will be... MPH will improve sightly as well, but your ET will most certainly improve... Its a concept I've only just got my head around, average horsepower applied... But it makes a whooooole lota sense when you see just what the difference that it makes is... What gave me the revelation of this was Pro Stock cars. The don't put out thousands of horsepower like door slammers, but they run similar ETs at less MPH. They have less outright power, but they have 5 or 6 speed's in them, very VERY fast shifting 5-6 speeds (auto's I think, the clutch is only for laucnh.. Not sure, will have to get back on that), and the average applied horsepower (not torque, torque is not as close) over the quarter mile is similar... If just a little less. Meh, I think its a fascinating concept, then again, I love anything that makes power and loud noise.... But you get that

Yeah, yeah. Will quit showing off with that 6 speed already. I can't get more jealous than I already am. Congratulations on your choice of car Todd. You'll love it. Why ? Didn't Motor prove the old 5 Speed is still quicker than the new 6 Speed ? Nope.....

235/45/17 = 25.3268 I think they chose to have the 245s in the 18's because all previous XR8's , GT's and T series cars had 245 tyres... For some reason there was a big enough difference (grip wise) to warrant having these tyres for those cars. that's what I'm assuming though, don't take it as gospel....

On the rear though, if you do have deep enough pockets to do so, go for 275/30's... You will need allot of cash to get tyres of that size (so don't do to many burnouts!!!) but the extra grip is awesome.... Plus if you get a good tyre, they handle allot better in the wet. Also, just so you guys have piece of mind about the diameter difference, check it out... 245/40/18 = 25.7165in 245/35/19 = 25.7520in As you can see, 2 hundreths of stuff all difference! If you could ring out 6th gear in the T, it would give you only an extra 0.45kmph (at 304km/h)... BUT! 275/30/19 = 25.49606299 Actually has a smaller rolling diameter! Brilliant! I'm bored....

Then again, hemi's are awesome too..... lol, totaly not OT, but I'm bored so... meh.

460 > 427.... Plenty of mild 460's making well into 500rwkw without chargers... They are awesome engines.

Ok I'll lighten up, my bad.... One last thing though, I'm not sure any of us really know what pressure the design team has been placed under while they come up with these specifications and such... Budgets to be met, time restrictions, resource restrictions.... Allot of things could be better, but is it cost affective? Can it be finished and completed in 3 months? etc etc....... Allot goes into it, and most humans tend to forget small things when under extreme pressure... So I guess what I'm saying is, give some of them a break... Sometimes its not the designers fault... They did the best they could, then gave it to the manufacturer to build something as close as possible to the design... That isn't always the case.

Take from Spleens link... So Bitsumissing are removing crap like DOHC VCT to use the money for nicer ..... door handles.... Sounds like they are onto a winner there. I know, how retarded... You can never get the efficiency of a properly setup duel overhead cam engine with fully independant VCT. If the overlap between the inlet and exhaust cams cannot be modified, increasing efficiency is never going to be optimum.. You can never get reburn (when not all the exhaust gases are expelled, some of them are reburned to increase efficiency). That is a major point for efficiency because it decreases emissions in a huge way... Someting like 15% in closed loop conditions (its useless in WOT). The fact they have done so well with SOHC is an acheivement, but it will ALWAYS fall behind in finding the uttermost pinicle of efficiency.... ALWAYs... Its impossible to have the best of all worlds without a compromise.

Ahhh yes, professional mechanical engineers. You mean like the ones employed at Ford who have given us such magnificent pieces of engineering excellence like the AU/BA handbrake. And the diff clunk. And the sh!tty brakes. And the clunky gearboxes. And engines that won't idle. OK I'll stop now as I'm depressing a lot of people ... :blink: Respect where respect is due please mate, grow up. I wasn't attacking you, I was just helping out. No need to go on the attack, especially if you can't do a better job yourself.

How much does the stock bonnet weight compared to these ones? Whats the saving? Surely it would make at the very least a slight difference to the cars overall balance? (for the better).

Good to hear mate! Keep us posted

Just to add a little. The CL 65 AMG makes 1000nm of torque standard and still runs a 7 speed auto. Believe me it makes a difference even down the quarter! Provided that the box is strong enough and built well enough to handle it. Can't wait to see your car run down the quarter man.... Any plans on building a strengthened ZF 6 speed and then fitting it to your beast? Now that would be something else! Mmmm....

You have 2 cars. 1 has a 3.73 diff, the other has a 4.11 diff. That is, 3.73:1 and 4.11:1 respectfully. Both cars are running identicle drivetrains appart from the afformentioned diff change... For every 1000rpm which car moves slower? The one with the HIGHER diff ratio, the 4.11:1 will be going slower. This ratio, the 4:11, is considered to be SHORT diff, but HIGHER in ratio..... Basic primary school maths teaches us that if the input number is higher in one ratio vs another ratio, then the ratio with the higher input value is considered to be the higher ratio... That means 4.11:1 is a HIGHER ratio than 3.73:1. That is, there is MORE input speed required to get the same output(1) speed. Its based on input vs output... Hope that clears up where I'm coming from.... btw, 2 professional mechanical engineers agree with me... They are also car enthusiasts. They both earn allot of money to be exacting in there profession. I'm going with their call on this one...

I think you did an absolutely brilliant job here mate. Infact, this would be the best tune I've seen with those, or similar, modifications. Yes, nizpro did the tune, but it just seems to me that you gave them the best possible start by giving them a strong and efficient base to run off... Also, having a 3psi stock map, that's unreal! That would be the most instant power for a turbo car... Surely it would feel like an NA, just stronger! Brilliant for a valet map... You made there job extremely easy mate, I aplaud your efforts, fantastic job!