djr81

228

Roy rake angle can be best understood by referring to the difference in front & rear roll couple & particularly the jacking effect of the rear suspension. But more easilly by referring to the front ride height relative to the rear ride height, ie nose down versus nose up etc. Having adjusted mine a few times I can make the following observations: A nose down car will turn in very well but then tend to wash out through the corner. A nose up car will not turn in well enough. A car with the proper rake angle will have a good match between the balance on turn in and the balance at the apex of the corner. So you don't for example, turn the thing in only to find yourself understeering & missing the apex of the corner by a foot because the front end has lost interest. Hope that makes sense.

sorry mate, its just a plain Jane Gt-R.

Yeah, come on Dan, there hasn't been a flare up in the ECU wars for a few weeks now.

My rear camber was 1 degree 15 minutes & the ride height 345mm. As I said it fouled until the guards were rolled.

I am particularly glad no one bothered to read my first post. There are several things to consider. 1. For a turbo motor the higher the pressure ratio that the compressor is running at the higher the temperature will be at the outlet. So what the hell does that mean? Means that if you inlet air is less dense because of flow restrictions the turbo needs to work at a higher pressure ratio to flow the same mass of air which in turn means the air entering the intercooler is hotter. Airflow restriction bad, no flow restrictions good. 2. The circumstance in 1 is no where near as bad as running you pod in hot engine bay air in the first palce - see my first post. 3. The amount of air being shoved around the engine bay through the radiator both by the cars motion & the fans will be more than that going through your cold air intake. So seal the cold air intake from the engine bay gases. 4. You will get heat soak even with a good intercooler on a hot day. Have a look at the attachment. Compare the blue lines - the second of the two shows acceleration falling of only when the I/C gets hot.

You are correct - up to a point. What you have neglected to mention is that as the gas cools an increase in density means it sees a DECREASE in volume. So measured in cfm (or whatever units people prefer) there is much less VOLUME of gas to be removed. In an exhaust the velocity of the gas is proporional to the volume of gas. The result of the lower gas velocity & the lower volume is that there is a lower pressure differential needed to push it out the back, that is back pressure drops. The effects of a reduction in volume (driven by temnperature change) is much more influential on pressure drop than the effects of an increase in density. I am not going to post up the calcs for this, I am sorry but they are complicated at best & not really of much help unless people wants to spend hours studying fluid dynamics & compressible flow. But the short answer is the more temperature you can dump out of your exhaust gas the less back pressure you will see.

Speaking of Alcons calipers - you didn't happen to write down the caliper part number by any chance?

Innovation is great. It is one of the things that marks F1 as the pinnacle of motor sports. Unfortunately the era of the revolutionary design & for that matter privateer teams (Lotus, Brabham, Tyrrell, March, Jordan, Lola etc etc etc) has passed. The kinds of budgets provided by the manufacturers is eye watering. But how long will, for example, Toyota be willing to keep throwing hundreds of millions of dollars to allow Schumacher to make an arse of himself on a Sunday arvo? Or Renault if the results don't return? Or Honda is they keep this years form up? The popularity of various categories & even motorsport as a whole waxes & wanes. Hell WRC used to be lined with manufacturers - now there are only three. The BTCC had nine or ten FACTORY teams. Now it only has a couple. Remember the Group C sports cars? I don't think it will have slipped Toyotas attention how much they need to spend in F1 to get nowhere compares to how much they are spending in NASCAR getting nowhere.

Well the current point system hasn't been current for very long. It used to be 9-6-4-3-2-1. So if you finished 7th you got SFA. Wasn't such a problem when the cars weren't so reliable as the minnows could snaffle points still. But when you had the 2 Ferraris, the 2 Renaults & 2 random other cars finishing every race the other makers didn't even get a sniff. So they changed it. The best way to promote overtaking is not to fiddle with the points but to make it easier to overtake. But I reckon that conversation has been had once or twice before.

This may save alot of time for you: Blue is the air filter temp. Pink is the compressor outlet. Yellow is the I/C outlet. Cyan if the throttle body. Car was a skanky RX-7 with a Chinese front mount & an unshielded air pod. Note the bad arsed heat soak on the I/C when the car is at a standstill last in the test. Not good for drags or hillclimbs..... Conditions: Ambient 15 deg. Drive down hwy at 100 k's, brake and accelerate from 2nd gear throught to 8000 rpm in 4th, cruise for about 30 sec and the accelerate from 3rd gear to 8000 rpm in 4th. Stop and idle for about 45 seconds shortly after. Temps at 8000 rpm in 4th for first test: air filter 48 after turbo 117 after I/C 45 throttle body 51 Temps at 8000 rpm in 4th for second test: air filter 47.3 after turbo 122.6 after I/C 45.9 throttle body 53 Temp at air filter after stationary at idle for about 45sec was 84 deg! Thermo fans switched on and filling engine bay with hot air obviously. So, based on the above results for the second test lets to some 'what if' scenarios based on different inlet temps to see what effect they have on the after I/C temps. Intercooler efficiency = 71 %. Temp rise across turbo = 75.3 deg. Using these figures some calculated and an ambient temp of 15 deg, after I/C temps are: Assumed inlet temp/Calculated after I/C temp 15/ 36.6 20/ 38.1 30/ 40.9 60/ 49.5 80/ 55.3 So if I can get the inlet temp before turbo down to 20 deg (allowing for 5 deg pre turbo piping heat soak above ambient), I should get a reduction in after I/C temp of 7.8 deg. Which is not that big a deal for high speed driving (ractrack), but I'll still be sorting out an out of engine bay filter location given that most events I do have a standing start followed by a lot of slow speed (2nd and 3rd gear) work.

Thanks man, I sort of suspected they might have been. The 343mm size is about all you can stuff under a 17" rim. Even then it works out to be 13.5" diameter. Which leaves a nominal 1.75" on each side. I say nominal because there isn't anything like that amount of room.

I think you are getting a bit mixed up. Fibre reinforced materials are usually much better than their equivalent homogeneous counter parts as far as crack propogation resistance is concerned. Unfortunately they are not so good when basically sand blasted. This can remove the resin from around the fibre reinforcements & then allow the component to fail. As Rolls Royce discovered on the RB211 before they went bankrupt.

Ofcourse Nissan recommend it - they sell it don't they? Exxon-Mobil, BP (Castrol) etc etc also spend an absolute shitload of money on R & D. The Nissan oil isn't "bad", just the other oils are better. Bottom line is look at the API rating on the container. It should be SM as a minimum. If it doesn't then move along.....

My 17x9 +22 foul the rear guards (Or did - I had them rolled) with 255 RE55's on them (RE55 are rumoured to be a bit wider than roadies marked with the same width). On the front it is a different story. As you start to wind camber in the top of the tyre disappears into the guard. Everything clears ok, but it ends up looking undertyred. I could easilly run anything down to a +8 with only 2 and a bit degrees of -ve camber. Bottom line is that +22 appears to be the default offset. But as the Baron said ride height & camber settings make a BIG difference to how the things look & how they fit.

Nah, the 707160-5. ie the ones on the link. They are cheap (er than HKS stuff) & if you check the compressor map (something HKS dont/wont provide) you can see how efficient the compressor is. I was worried that they were a little large for the RB26, but the dyno chart says different.

Why the hell are you using mineral oil in a turbo motor? The Nissan oil is better than the Catrol magnatec as it is atleast semi-synthetic. Better still are proper syntheitc oils. Do a search & you will find endless guff on oil.

Yeah good point. If I want to see control chassis & crap drving I will watch the A1 GP's. Half the reason you watch F1 is to see what stupid amounts of money & talent applied to racing cars can achieve.

If you can get your hands on a tape/DVD of the 94 GP from Adelaide you will see how hard the things were to drive without T/C or good downforce. The cars had been hacked about in the wake of the Senna tragedy & by god did they look ugly to drive. Entertaining, but ugly.

I think your timeframe is a bit ambitious. Yeah fair point. I don't think the likes of Williams gives two squirts of donkeys piss whether or not their latest seamless shift transmission ever makes it into someones bloody Camry or not. Patrick Head has basically said so, just no quite so eloquently. I think half the problem is that, with unanimous agreement required for most of the rule changes there is always someone tryign to protect their immediate, short term advantage. Usually to the detriment of the spectacle of the sport. I wish they would just piss the T/C off & allow the cars to go back to their 200cm widths. Here is hoping the Bahrain race is a goodun. Would like to see Wurz stick it up Rosberg.

Gee I don't know. Used to be that the cars were much less reliable than they are now. Habitually you would be lucky to get half the field home. Hell I was reading the history of March last night & from the '71 Monaco GP seventh place was two laps down & not running at the end. Field was bigger than it currently is. I would prefer the money be spent on mechanical improvements than on aero. There is basically zero chance an aero development will ever help anyone or anything other than an F1 car designed to the current regs. Atleast with the motors & other mechanical bits there have been gains in such things as metallurgy, adhesives, fuel systems etc etc etc. The idea is to get more performance without eroding the reliability.

The Garrett's.

I don't think you will find any difference between the povvo pack GT-R front bar & the N1 item. The slots just fit in the bar after it has been cut. But if you want a number the Nismo editions were BNR32-100195 ie in the range of 100000 to 100560. Pick one, pick em all...

Always a bit of a worry when you have stumped up for the cash & you start seeing topics like this. http://www.turbobygarrett.com/turbobygarre...0R_707160_5.htm

Well firstly, I cannot believe that any Formula One team would ever waste money. I mean, running a couple of wind tunnels per team 24/7 + ungodly amount of CFD grinding away on massive computers to produe a few little aero tweaks can't be viewed as a waste, can it? Teams will spend ridiculous amounts of money in any type of motorsport chasing any gain they can. Doesn't matter if it is in getting a motor to rev from 20,000rpm to 20,100 rpm or just finding a few more Nm of torque in a rev limited motor. The may as well spend it on engineering, they only end up pissing it away on corporate entertainment that I can't get a sniff of. You are right. F1 used to be pretty straight forward. Fill the thing up with petrol, drive the ring out of it & change the tires if you have to. Now it is endless amounts of bullshit - presumably to give the commentators something to rabbit on about whilst the procession drones around and around. It's sooo f$cking boring as Murray Walker was impersonated as saying.