Guess my rwkw from these mods!

[Roy]

I'm not sure, but doesn't it ditch your climate control along with many other aftermarket ECUs such as Motec? This could have been something they've fixed, but I seem to remember way in the past reading that it didn't support the Skyline's climate control.

For a mild car, all I can see in an Autronic would be a higher initial purchase cost, higher tuning costs, a limited number of tuners that could do it, ...

Price for an SMC is $1585 inc GST, then $220 (or was it $250 for auto tune), need to mess around with CAS and of course have to have it installed. So is more expensive then a PFc. But not by the amount that ppl seem to think, especailly since some are paying $1400 for a PFc. Plus whilst the auto tune still requires a car to be tuned, it speeds up the process.

As for not as many tuners, again you are right, but the number of quality tuners is a different thing. My car is no race car, but im far more comfortable with a shop that prepars race cars/engines and has years of experience with Autronic, that also prepares road cars and club cars tuning my car, then a place that has a dyno and can tune a plug in ECU. Not saying PFc tuners cant tune...or course they can, its just that i dong think the tuning costs and number of tuners is such as issue...initial purchase and installation cost is for sure. I

f you are in Sydney then the Autronic rep can istall and tune a SMC for $2500, and thats from a bloke that got my old R31 with MT8 to drive almost like the factory ECU, so definitely no wide open throttle/drag only tune...but a nice road car tune

As for the climate control i think you will find thats a completely separate thing, perhaps you are thinking about idle adjustment for when the air con is switched on...ECUs are so horses for courses...

As for the drag times, pay the coin and find out, plenty of big hp cars running good times, plenty of cars with less power running better times

[Lepperfish]

190-200RWKW depending on engine condition ect ect..

Id say get the PFC, seems to be most popluar choice amongst SAU members..

[Guest INASNT]

But firstly stop watching Fast And Furious so much

[jamesh3]

Lol, I think some people dont know what double clutchin is. I used to think it was something else because my mate would do it and i just didnt get it.

Double Clutching:

In a Nutshell, the result of double clutching is that you get higher boost much quicker when shifting gears, only purpose to double clutch is in a Turbo car.

The action:

Double Clutchin is when you change into the next gear you release your clutch to start getting the wheels accelerating again but you push the clutch in quickly for the 2nd time *double* and release it quickly in the gear you just changed into.

This small amount of time while your reving with the clutchin in your boost climbs quickly and once you release the clutch again, you have a higher boost level giving more power after just changing gears. Usually in lower gears like 2nd, Double clutching will get you will spin in the rear, but in gears like 3rd and above, it gives you that boost quicker giving you more power, and a quicker time to reach your next shift... Add it up over your shifts, you'll shave some time off your run.

If you do a Flat shift, your boost climbs up as you keep on accelerating. With double cluthing, more power is already there and gives you better acceleration.

I was taught this by a guy who has an EVO VII engine in this import Mitsubishi Fouby, and it is certainly faster when doublecluthing. I practiced it in my car and its certainly faster. I would only do it when racing, it is harsh on your clutch.

I suggest people to try it and see for themselves… I just hope you understand what it is exactly. Pretty much after you changed into your next gear release the clutch, then quickly push it back in again and straight back out whilst Still keeping your foot on the throttle.

:run:

[jamesh3]

you only need to double clutch a non-syncro gearbox, like an old truck or something.. meaning push the clutch in, let it out when its in neatural and blip the throttle,  push the clutch back in and finish the gear change...

Thats not the type of Double Clutching I'm talking about, although i have had many people call it this, When people hear about Double Clutching and say "What that makes no sense, theres no point" They are thinking of the WRONG type of Double Clutching. I suggest you read my explanation on Double Clutching when racing.

[jamesh3]

Dude the car does Nkm/h at Xrpm regardless. You will not change this without changing the gear ratios in the gearbox or the diff.

I thought the same thing! I cant understand why I get an extra 20km/h from 3psi, I would think at 6500rpm in 2nd gear, you would only to be able to do what is the result of its ratio, which is 80km/h when i run stock 7psi.

I have a GReddy Profec B boost controller, I turn on the High Boost setting @ 10psi and I can do 100km/h in 2nd gear at 6500. I Dont understand it much either, but once i get my PowerFC, i will boost up to 14psi, and see if i can go even faster at the same rpm. I think you and myself needs to have this explained by some1 who REALLY knows there shit.

All i'm telling you is what happens, and how it happens is another story.

Owww I'll also let you know. When i boost up a hill *eg ourimbah mountain*. I'll be driving at 3000rpm under vacuum coz not on pedal much, it'll quickly rise to say 4000 rpm and run its full boost. But my speed will be climbing very quickly from 130, 140, 150 etc. While my revs are only climbing very minimal, 4200, 4400, 4600. DONT Trust me on those figures its only an example.

But all i know is that when i Boost in my car, regardles off Where the Revs are at, or how they are increasing. Boost gives you more power, which is somehow converted to the wheels and gives me Higher speeds! Dont ask my how, ask an expert, a person who actually works on that type of stuff.

[meshmesh]

No offence, jamesh... but I think you have just re-invented the wheel! And maybe you need to go out & give lessons to all race drivers throught the world. Mate you nowhere near it.

What you have just described is known as "fanning" or "stepping" or "popping" BUT NOT DOUBLE CLUTCHING .. commonly used by motorclyclist (eg: 2 strokes wanting to hit band) probably the worst thing you could do to your clutch and drivetrain. Yes your correct this is only good for turbo cars, because and mainly used during rolling start runs. EG: I'm in (any gear you want say 4th for arguments sake) My boost doesn't hit till 3000rpm, my revs are showing 2500 at our rolling start speed.. the guy next me says GO, Whilsts I'm flooring it, I "pop the clutch" or "fan the clutch" to throw my car into a semi neutral, the revs fly up I release & I'm suddenly building boost. Bingo...

Double clutching is as already described and "to some extent" better when going down gears from 4th to 3rd or 4th to 2nd, and most effective whilst going up hill so you don't loose momentum, and prevents compression lock, but so does heel and toeing.

[meshmesh]

I thought the same thing!  I cant understand why I get an extra 20km/h from 3psi.

I turn on the High Boost setting @ 10psi and I can do 100km/h in 2nd gear at 6500.  I Dont understand it much either, but once i get my PowerFC, i will boost up to 14psi, and see if i can go even faster at the same rpm.

Question: Jamesh.. be careful what you say mate you might find yourself in quarantine very soon! by the sounds of it.. i think you may have a UFO on your hands. Or your car is the only one of it's kind inthe world and maybe fitted with VBGR-TEC "Variable Boost Gear Ratio's - TEC"

Hear me out, cause I might have to slap myself in a minute to make sure I'm not going loopy aswell -

Let's do some maths here for the hell of it.. Math guru's correct me if I'm wrong.

Your saying by increasing your boost from 7psi by 3psi to 10psi or (45% gain) gives you an extra 20km/h from 80km/h to 100km/h in 2nd gear (increase of 25% gain in speed) Based on that theory, if you were to increase your boost from 7psi to 14psi this what would happen based on your theory:

Example 1.

In 2nd Gear @ 7psi max speed =80kmh

In 2nd Gear @ 14psi max speed =124kmh

I wanna know what sort of gearing your running coz I want it.

Example 2.

Your cars speedo says 240kmh and the max speed is 240kmh @ the factory boost of 7psi.

In 5th Gear @7psi max speed =240kmh

In 5th Gear @14psi max speed =372kmh < Maybe you drive a Mclaren?

My calculations are based on jamesh's theory of every 1% increase in boost equates to 0.55% increase in speed.

[jamesh3]

My calculations are based on jamesh's theory of every 1% increase in boost equates to 0.55% increase in speed.

Hahah this is your theory, not mine. I dont have a theory, i can only tell you what is happening. I simply think you, me, & every1 else doesnt quite understand how power is converted to the actual wheels.

If im running at 4000 revs. at a speed of say eg. 75km/h. If i boost up a hill and still keep the revs around 4000 the car might gain up to 85km/h.

Boost gives your more power to put it simple, a Harder Bang from the engine regardless of RPM, boost gives power. Now somehow this power is converted to get it to the wheels. So it makes sence to me that If theres more power, theres going to be more speed, but how this is actually converted I'd dont know!

I'm getting pissed off with every1 saying it doesnt make sense so I'll ring up my this turbo specialist Mechanic and see what what they have to say.

Maybe we're thinking or going a totally wrong way about this, i dont know. But to put it simple. I get 100km/h in 2nd with higher boost compared to a regular 80km/h. I think my next test is to see how fast i can go in 3rd on Standard boost, then up it. I'ma Ring my mechanic and find out!

:run:

[meshmesh]

Your not SydneyKids long lost son? by anychance???

[jamesh3]

What you have just described is known as "fanning" or "stepping" or "popping" BUT NOT DOUBLE CLUTCHING .. commonly used by motorclyclist (eg: 2 strokes wanting to hit band) probably the worst thing you could do to your clutch and drivetrain. Yes your correct this is only good for turbo cars, because and mainly used during rolling start runs. EG: I'm in (any gear you want say 4th for arguments sake) My boost doesn't hit till 3000rpm, my revs are showing 2500 at our rolling start speed.. the guy next me says GO, Whilsts I'm flooring it, I "pop the clutch" or "fan the clutch" to throw my car into a semi neutral, the revs fly up I release & I'm suddenly building boost. Bingo...

Double clutching is as already described and "to some extent" better when going down gears from 4th to 3rd or 4th to 2nd, and most effective whilst going up hill so you don't loose momentum, and prevents compression lock, but so does heel and toeing.

You got that one pretty much spot on, well explained... It's also called double clutching by people, it seems the term 'double clutching' has 2 different explanations and most people think the other. From now on so theres no confusion i hope I'll be calling it "fanning" or "stepping" or "popping" hehehe.

[jamesh3]

Now that we have Double Clutching / Popping sorted out i cant stop thinking about this Boost / Speed occurrence...

I'm thinking, is it possible that because im using a boost controller and my ECU is stoping me at 10psi that my ECU is actually ****ing around with my speedo and showing me a speed which im not actually doing? I highly doubt it as for i would think the Speedo would be calculated on its own but I'm just trying to think of other ways Besides "gear ratio" which is causing this. I must say it certainly feels like 100km/h... How i get it i dont know.

Can we please get some examples?

Anyone who has an r33 Gtst, How Fast can you do in 2nd gear at rpm and boost level?

I'm sure with enough thoughts thrown in the air we'll end up figuring out whats going on

If you know any mechanics or pro's in this area it would be good to ask them and find out what could be going on?

:run:

[Ronin 09]

I am a mechanical engineer. Let me firstly say that your response is a little misguided.

If im running at 4000 revs. at a speed of say eg. 75km/h.  If i boost up a hill and still keep the revs around 4000 the car might gain up to 85km/h.

Lets see here. Your engine has a rotational speed of 4000 times a minute, that is, if you were watching a dot on the flywheel (and you could actually see to count it - smart things, these computer whatsits), it would buzz past a stationary reference point 4000 times in 60 seconds, or, 0.015 seconds per revolution. Stay with me here, professor.

Now, say you are able to keep a constant 4000 rpm, which, when your clutch is engaged, will feed 4000rpm into the gearbox. Assuming that all power is transmitted to the gearbox (no frictional losses etc), the input shaft is spinning at 4000rpm as well.

Say you are in second gear. I don't know the ratio, but say for arguments sake it is 4:1, that is, for every 4 turns of the input shaft, the output shaft from second gear rotates once. Now, the output shaft is spinning at 1000 rpm.

So, assuming no losses again here, this gearbox output shaft spins at 1000rpm, which then buries itself into the lump of cast iron we call a diff hanging between the back wheels. So, now assume that the diff ratio is 5:1 (geez that is short isn't it), that is, for every 5 turns of the input, the rear wheels turn once.

So now in the system described, the rear wheels turn 200rpm when in second gear, and held at an engine speed of 4000 rpm. This means, for every one revolution of the wheel, the engine turns over 20 times for this gear ratio.

Boost gives your more power to put it simple, a Harder Bang from the engine regardless of RPM, boost gives power.  Now somehow this power is converted to get it to the wheels.  So it makes sence to me that If theres more power, theres going to be more speed, but how this is actually converted I'd dont know!

Now lets look at your next statement. You are (partly) correct, boost enables the production of more power, but in itself does not give you more power. Boost increases volumetric airflow, and as we know, air + fuel = bang (power, and torque when the force is transferred rotationally).

Now this 'power' is transmitted by the drivetrain to the rear wheels, but it is the torque, or rotational force, that will get you moving and accellerating. We have gears to multiply the torque produced from an engine (or power source, eg. man on push bike), but we will eliminate this scenario here, because we will assume that we remain in second gear, and the torque transmission will remain the same.

Now that we are on the same page, be aware that, the gear ratios of the gearbox do not change (unless you have one of these trick CVT transmissions transplanted in the sky), nor does the the diff ratio - it is a fixed relationship between:

1. engine rotational speed;

2. rear rotational speed; and hence,

3. vehicle road speed.

You are right, in that if we increase the boost, the engine will flow more air (holding the same RPM) and can produce more power. The will have exactly 0 effect on the road speed at the same RPM. The only effect this will have is, your car will produce more torque, which means it will get to your desired road speed quicker i.e increase acceleration.

Maybe we're thinking or going a totally wrong way about this, i dont know.  But to put it simple.  I get 100km/h in 2nd with higher boost compared to a regular 80km/h.  I think my next test is to see how fast i can go in 3rd on Standard boost, then up it.  I'ma Ring my mechanic and find out!

Bottom line is, if you increase the engine speed, your road speed will increase, no ifs, buts, or maybe. At the same RPM in the same gear, at 5psi or 300psi, you will be travelling at the same speed.

Hope this was clear.

[Ryno]

Jamesh,

It sounds like the wires to your boost gauge, have been incorrecty wired to your speedo.

If you think increasing boost for a set RPM will give you an increase in Speed, you're going mad!

[jamesh3]

You are right, in that if we increase the boost, the engine will flow more air (holding the same RPM) and can produce more power.  The will have exactly 0 effect on the road speed at the same RPM.  The only effect this will have is, your car will produce more torque, which means it will get to your desired road speed quicker i.e increase acceleration.

Bottom line is, if you increase the engine speed, your road speed will increase, no ifs, buts, or maybe.  At the same RPM in the same gear, at 5psi or 300psi, you will be travelling at the same speed.

Great crashcourse lesson on getting the power to the wheels, well done. Ok well it seems then all I can think off is that my Speedo is playing up with the ECU. Because i cant hit even 90km/h in 2nd running standard boost. But your right, regardless of boost the gear ratio should only achieve a certain speed in that gear.

If anyone has any idea's on why im seeing this speed difference from 3psi then they'd be the icing on the cake to end this Thread.

Thanks again Ronin 09 for your great post.

:run:

[meshmesh]

My Mistake... Sorry jamesh,

Ronin is SydneyKids long lost son

Damn you Ronin.. I really feel like a duma$$ after that read, I suppose that may have something to do with getting kicked out of high school in Year 10

[Blade]

So double clutching? was jamesh right?

I seriously thought double clutching was depressing clutch entering neutral, get synchros moving release clutch once in neutral then depress quickly and enter gear?

[jamesh3]

Jamesh,

It sounds like the wires to your boost gauge, have been incorrectly wired to your speedo.

If you think increasing boost for a set RPM will give you an increase in Speed, you're going mad!

Lol i dont think im going mad, i know what im seeing, but most likely my cars going mad! Like i said, I'm gona ring my mechanic, see if he can think of any reason. I like the theory of boost gauge connected to speedo! hehehe

:run:

[jamesh3]

So double clutching? was jamesh right?

I seriously thought double clutching was depressing clutch entering neutral, get synchros moving release clutch once in neutral then depress quickly and enter gear?

I was right, you where right. Double Clutching has a Double meaning it seems... lol

You'll find some people think its what you said, and others what i said.

What i meant is what Vin meant in Fast and Furious. Most people think Double Clutching is what you think, and if they think that, then they think old boy Vin's speech is bullshit.

But after MeshMesh's great explanation on Double Clutching which is called Popping or Fanning, Vin is right and it should all make sense now!

:run:

[LOW25T]

im suprised no one wrote this guy off, very impressive