Discussion in 'Member's Garage' started by ProckyZ89, May 3, 2012.
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So our fuels are equivalent, but their chassis dynos somehow work differently. I didn't know this, will look into it. I'm only familiar with engine dyno principles, which should be the same worldwide, I don't know about all the chassis dyno fudge factors.
I've found a few bits of info supporting a single GT2560 making about 300hp on various engines, and 300whp in the U.S. (Their dyno differences maybe).
Thanks for the info SRB-2NV about the compressor flow equalling the theoretical power rating. I didn't realise it was that simple. So maybe some flaws in that theory, unless the 33lbs flow is an actual measured number, not just calculated.
I see what your saying about temps being a problem if using a 330hp turbo on an otherwise 800hp engine. But are you taking into account if the compressor can only flow 330hp, then it's going to choke the inlet, much like the intake restrictors they use in various race classes. So won't this be equivalent to doing a dyno run at say half throttle, with the intake limited to 330hp? Therefore the exhaust flow is also equivalent to 330hp, so you'd only get typical exhaust temps. But max out the turbo.
Sorry Procky, I'm just trying to learn a few things but completely hijacked your thread in the process.
I am sure that the 330hp number is not at the wheels.
No, you're right, it can't be at the wheels, because Garrett would have no idea what the various drive train losses will be. Their rating has to be engine hp.
This should help
I would have said common knowledge
It really depends if the turbo is well suited for the engine its on. For example ive seen 500hp rated gt30 turbos make 490rwhp on rb25s.
Death of last engine
So it looks as though, after disassembly. By my friend Matt Holt, that I had spun big end bearing on 6 ... As well as some signs of oil starvation
So a rebuild was definAtely the right call of action in my case
Do you know what caused it?
Had a lifter tick that got progressivly worse for 3000km
Even after trying fixes.
Then on way back from zedfest noticed oil pressure sitting lower than normal. By time I was home had turned into a full blown bottom end noise.
who is rebuilding the motor?
After stripping your motor more your knock was from cylinder 1, going to disassemble the pump to find what caused the oil loss.
Bores and pistons are in good condition (for the age) crank has damage from spinnng a bearing and the oil loss.
I've been slack with this,
For those who recall a previous few postings. My wings west rear bar posed a rather large performance issue in that it generated ALOT of drag catching air under the car.
Searching for a functional (in theory) diffuser to seal from diff to rear bar and cover the large void. I found a perfect example from Glen!!
With a few slight modifications and an adjustable mounting bracket to alter the rake angle As I need. It's on,!!
A snip to the rear bar and it's now subtle and functional.
Now, we also here people say "the best mod I ever did" ..."makes the car feel 200kg lighter"... Etc regarding diff ratios.
TT factory is 3.69 diff and on the .752 5th gear is huge.
So I looked for a better option.
A lot said do a NA subframe, it's lighter and has a 4.08 diff.
But it also has weaker 5bolt shafts and IMO diff.
So I hunted for a rare set of 4.10 Richmond Leader Gears! Found a BRAND NEW set from shane001, sourced a R230 diff from Rob260, had it
*rebuilt with all new seals, bearings, and measured up and reset.
4.10 diff ratio
Strength of R230 and 6bolt shafts
Better response,acceleration in all gears
Got this all installed at Unique Auto Sports and had new Nismo bushings installed front and rear. Back end is super firm and just beautiful to drive now! =D
Also been busy with another project
More to come on that soon /on completion.
I think the undertray is mad. But I just don't see the bumper being as massive a performance inhibitor as you think it is
If it was catching that much air at speed... it would rip off. simple. has it got stress fractures in the paint anywhere?
on a 2 seater it is ..
Ok, let's look at this for a second
2+0 have the fuel tank behind the seats
2+2 have it in the back
So the 2+0 have a large cavity between the rear subframe/diff and the rear bar.
Factory rear bars this likely doesn't present much an issue but for any rear bar lower hanging especially
Even the low bar stillen or strosek
You effectively create an air scoop underneath the car with 2 small exhaust holes for it to try and turbulently escape.
Now today on v8 Supercars, one had a rear bar fractured and pulled out (smaller in surface area than what the total removed section of mine was) to which race team engineers said that it was costing them up to as much as 8kmph down Conrod until it was fixed.
If I apply the same logic to cars using "air brakes" like the Veyron and Saleen.
You could argue when "AT SPEED" there is indeed a large drag on the car sacrificing efficiency to achieve the current speed and also the resulting trap.
I do have a few stress fractures on the paint which is even more so worrying as on a urethane bar with an elastic based primer so it's not really able to crack.
Want to test this?
Drive at 50kmph
Hold a pillow case secured between 2 sticks out the window
Drive at 100kmph
Hold it out again
Drive at 150kmph
Repeat then try at 200kmph
Dude I'm not trying to sit here and tell you that parachutes don't work. I'm saying that the effect would be SFA unless you were going very very very fast. You don't even have a flat under body on the car, any air there will be whipping up all over the place and likely will have escaped out past the side skirts and wheel wells... cars with ground effects have full flat under bodies with air guiding fins starting sometimes as early as 1/2 way up the car to ensure the air is guided all the way to reach the back.
V8 supercars are a different ball park... those guys are out there catching ever little split second they can to make their times lower. you're in a street/show car with a bumpin' sound system.
this is what happens when bodywork really catches air flow https://youtu.be/N5qL22iB29U?t=84
I think you missed the part where I ditch the sound system and redline change every gear legally on a road similar surface reaching 250kmph and loosing as much as 20kmph on the 4th to 5th change last year.
Without a air tunnel we are both speculating but given how low the rear of my car sits, it was catching air as a few can testify to by it "ballooning out" when I accelerate hard in front of them when over 100
I would very much want to hear those testifications
Aaron at zed fest
Ken who also raced at snowy last year.
You could be right perhaps it does do nothing at 200kmph+ speeds.
But I'm going to follow the theoretical principal that it does or should.
Btw that pillow example I gave, is more or less the height difference from a stock rear bar to how low mine sits below that level.
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