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Discussion Starter · #1 ·
Excellent news Tony,

Welcome to 285bhp @ the wheels. Yours shouild be quicker than mine with the same power because of all the stripped out interior.

I'd expect a mid-high 3 sec 0-60 and a flat 12, if not sub 12 1/4 mile.

Well done

Si
 
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Discussion Starter · #2 ·
yawns.......12's is SLOW , come back when your in single figures.....

And Tony, will you stop showing off about your wastegate..... and amp;lt;ok , im jelous and amp;gt;

Hey, f11ckme, just been out in a monster 32 skyline and whoopped a gsxr600 in
a straight line race, spoke to the biker afterwards and he was gutted.....

Man, these trick 32 skylines are FAST!!!!!!!!!!!!!


Justin
 
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Discussion Starter · #3 ·
Blade

Isnt that only 30 hp more than with std turbo? You said it's not set up properly and lacks fuel. Looking forward to what it makes after fine tuning. :D

Is std wheel bhp 215?
 
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Discussion Starter · #4 ·
Claudius - yeh it is only 30bhp or so more - but it hasn't really been setup - just the turbo bolted on!

Got a gems, new cams, different cam timing and full mapping to come - as well as new fuel delivery, 680cc injectors, fuel reg etc.

Hope to get around 330bhp at the wheels.

Simon - thanks! Amazing, it isn't even set up properly! Power is dropping at the top as the cams aren't right and neither is the fuelling.

Can't wait till it is set up right!
 
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Discussion Starter · #6 ·
More like 190bhp.

PE's rollers are on the pessimistic side at the moment because of the slip (the rollers are about to be removed to be recut).

I suspect the output is a bit more. Unlike most power runs (one or two attempts) my car is run on the rollers for a few hours, and the tests done then -by which time the gearbox is hot, air is hot etc. etc.

I think it will be quite alot quicker than before - shall see tomorrow am!
 
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Discussion Starter · #7 ·
Ok, this is very interesting.

Hope you guys don't get upset for what may seem silly or uneducated comments on my part, or for any questions that may have already been asked before on this board...

Disclaimer 1: I don't pretend to be an expert on any of this;
Disclaimer 2: Most of my information comes from talking to my tuner, and based on data from their dyno (he seems to know what he's doing, as he's the chappy who built Manuel Go's 470 wheel-HP, 10.9 second Evo)

Right, here goes then...

1) What's expected output of a stock Evo?
I understand that a bone-standard Evo 5/6 does about 210HP to the wheels? 190HP sounds very pessimistic indeed. The 210HP comes from above-mentioned tuner's experience with stock Evo's. This is here in the Philippines, using 97 octane petrol and with ambient temperatures hovering around 30 degrees centigrade.

2) Shouldn't the power loss from mechanical friction be largely CONSTANT on a given car, regardless of engine power output (all other things being equal,) as opposed to purely a %-age of total output?

To wit:

If a fully stock Evo produces say 210HP at the wheels, from a rated 280HP at the crank, then mechanical loss is 70HP, or about 33%.

Now let's say this same Evo's engine (and only the engine) is modified to produce 450HP at the wheel. If power loss is always approximately 30%, then this Evo should be producing close to 600HP at the crank, or losing almost 150HP because of friction through the transmission. But nothing else on the car has been altered, except the engine's power. This being the case, why should the SAME tranny (and other related mechanicals) suddenly be producing so much more losses than before (i.e, 150HP vs. 70HP)?

My tuner argues then that losses due to friction on any car are largely fixed, regardless of engine output. In the case of an Evo, estimated loss is about 70HP.

If he's correct, then a wheel HP reating of 286 should be closer to 350HP than 410HP. Blade, not saying you're wrong, but have you heard something that contravenes the above argument? What he's saying SOUNDS correct, intuitively-- at least to me!

Personally, I'd be chuffed if you're really getting more than 400 crank HP from 286 wheel HP, because for the next mod I'm contemplating, I'm being guaranteed 280 HP at the wheel. If you're right, I could then induct myself into the 400HP club! :D

Am I making sense? Or do I have my head up my @rse?

Cheers!
 
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Discussion Starter · #8 ·
Hi,
Seems very logic to me as well, that the power losses due to friction should be a fixed figure. I mean friction is the same amount of force regardless if the engine produces 280 hp or 450 hp, right?
 
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Discussion Starter · #9 ·
Yes,

Power losses should be pretty much the same as Power_loss |EQU| F_friction*V, V of the parts where the force is applied is proportional to the engine revs
and F_friction remains mostly the same (probably slightly fluctuating as a function of revs, gear). As a result Power_loss will be pretty much the same
during same revs at same gear (and not always a percentage of the overall power).
 
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Discussion Starter · #10 ·
When my car produced 285bhp @ the wheels on Powerstation's rolling road, the flywheel figure was 374bhp.

That calculates as 23.8% loss.

I'm not saying that the flywheel is accurate or the losses in fact. I'm more interested in the wheels figure. On the same day, on the same rollers, most of the other Evo's were losing about 28% through the drivetrain, I think because of my twin-plate clutch and mechanical diffs, maybe the drivetrain transmits the power to the wheels more efficiently than a standard car.

Just a theory of mine !!

Cheers

Si
 
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Discussion Starter · #11 ·
Guys,
Sorry to spoil the party but what you're saying is incorrect....
The coefficient of friction of the clutch material will remain constant as it is a function of the clutch surface.
When you transmit the power through the clutch, the clutch will slip in relation to the coefficient of friction. If you are trying to transmit more power through the clutch then the clutch will slip more easily and therefore the losses will be higher.

If the friction remained constant regardless of power then why does a standard clutch start to slip when the power is increased. It's because the friction between the surfaces has changed and the clutch is slipping and generating more heat therefore changing power into heat rather than driving the wheels.

Hope this clears things up

Andy
 
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Discussion Starter · #12 ·
I don't really understand this either, but having seen results of lots of EVOs rollered, the average loss on a 4wd car is 30% but varies due to many factors - particularly gearbox temperature. If you read between the lines of what I have said, I believe that my wheel figure is probably alot higher than 286 (probably near 300), because the car spends along time on the rollers being fiddled with (a couple of hours) (not just a quick power run) and the power drops alot over that time (due to the tranny being hot, air around the car not flowing etc, turbo getting hot etc.). The first or second power run is often the best.

All RRs are different, the most sensible thing for me comparison wise is to compare like with like on the same rollers. The 190 figure I was told by PE was OPTIMISTIC, as they have seen 180s from standard cars.

The other reason why the figures will be lower is that my car runs semi-slicks and hence will slip a little, and has a 1.5way LSD now too, and uprated center diff. My gearing is also different. Hence I believe the losses to be higher.

Perhaps comparing torque is a good idea - Simon, what torque figure are you producing, and where does it peak? Also where is your peak power? Mine is around 7800rpm now. If you really want to compare, we should go to the same RR on the same day, and run them side by side.

We need Droid for more explanation about losses - RR power loss king! Take a look at the Tuning Japanese website at the MLR day, and look at the graphs - huge variance in losses.

At the end of the day all power figures are crap and mean very little when looking at how the car actually drives and how it goes. So how does it go? Well, I can't really tell you because the suspension is so hard, and the weather is so crap, and the grip from the tyres is non-existent, that I couldn't really try it out properly. Will let you know after tomorrow - have a trackday, where I can fiddle with the suspension, set it up right and give it some...

The main achievement for me here was a wider power band. There doesn't seem to be any difference in lag (if anything, there is less) and power is strong all the way to 8000, where it was choking off at 6100rpm before - and all this without more fuelling, proper cam setup etc.

Can't stand that external wastegate though - noisy, yes - sexy noise - no. Suspect a new downpipe will come soon with the wastegate plumbed into that - can see myself getting chucked off a few tracks with that otherwise!
 
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Discussion Starter · #13 ·
Blade

You have given as good a reason for not doing RR sesions as there can be. The ONLY point, IMO, is to compare before and after tuning on the same car. The my car is better than yours type of thing is, in my mind, meaningless. However, I do admit that RR days are good socials.
 
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Discussion Starter · #14 ·
Agreed - think the seat-of-the-pants RR is the best way forward. I am probably a fool for quoting any number here anyway! :D
 
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Discussion Starter · #15 ·
Blade,

I've posted my torque figures before, here you go:

2000rpm - 165lbs/ft
3000rpm - 200lbs/ft
3500rpm - 300lbs/ft
4000rpm - 348lbs/ft
4500rpm - 340lbs/ft
5700rpm - 340lbs/ft
6000rpm - 320lbs/ft


As you can see, 348lbs is the peak at 4000rpm, it then back off slightly to around 340lbs and holds it until just under 6000rpm and then starts to drop away.

Also, my peak power seems to tail off around 6000rpm, yet when driving it will pull hard to the redline. I've mentioned before that I think its the LAP ecu I have which seems to richen up the fuelling too much at the top end, making the power drop off.

Si
 
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Discussion Starter · #16 ·
Simon,

Agree completely with you-- that only point of getting on the rollers is to determine the benefits (if any!) of tweaks and mods done to one's car. Given the amounts of money spent on some of these aftermarket add-ons, it's good to know that you actually derive some positive gains from them!

To a very large extent, the my dong is bigger than your dong argument evaporates in the heat of competition anyway. At a recent run what you brung track competition I attended last year (competing against the clock,) a stock (127HP) Civic beat most all comers, which included an S2000, turbo Eclipse and 200SX!

Having said that, there were no Evo's present that day. But if I had joined, I'm sure the Civic would have smacked me around too! :D
 
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Discussion Starter · #17 ·
Blade

Can you explain how you lose grip on the rollers with semislicks??


Andy

Can you explain why a twin plate wouldnt be less likely to slip and transmit more to the wheels?
 
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Discussion Starter · #18 ·
Claudius,
A twin plate would be less likely to slip because you are increasing the maximum torque capacity of the clutch by increasing the number of contact surfaces.

The maximum torque capacity of the clutch is dependant upon the number of contact surfaces, the clamping force, the coefficient of friction of the clutch and the size of the clutch face.
When the output torque from the flywheel exceeds the maximum torque capacity of the clutch, the clutch will slip and generate heat and this will reduce the power to the wheels.

Andy
 
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Discussion Starter · #19 ·
Claudius, because these Dunlops generate no grip at all until they get to the right operating temperature, unlike road tyres - and the only way to really get them warm is through cornering fast. Running on the rollers doesn't get them warm enough to grip. Was why I had probs at Oulton Park -couldn't get mine warm enough :)D)
 
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Discussion Starter · #20 ·
Original Post:
Andy

Can you explain why a twin plate wouldnt be less likely to slip and transmit more to the wheels?
LOL!! I'm sorry guys, this is not what I meant to say!! LOL IRL!!

Andy,

my question was, why wouldnt a twin plate clutch transmit more power to the wheels compared to a std one?

Just re-read your post and in fact I think you didnt say that. Do you agree the twin plate clutch will or may reduce transmission losses if you have good sticking WARM tyres?
 
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