Re: 2008cc 8.75:1 CR 3A G60 build.

by JNLRacing Sun Mar 29, 2009 4:17 am

I'll only divulge the info vaguely Very Happy

.

First of it's the first head I've done in this particular configuration and taking a slight risk knowing I had spare heads incase it went wrong.

Long and short of it I normally don't get given the intake manifold to play with after visual inspection I knew there was the chance of pushing things slightly further.

Long and short all heads I've always done have been based on the theory that there was no point in opening the port mouth up beyond standard as the restriction would be the intake. Which it is in testing by as much as 10% of flow loss in the upper lift range.

Realising the intake could be made better I set about getting the port cross sectional areas to what I considered to be mathematically perfect. The result was a good flowing head but port velocities where towards the lower end of the acceptable scale. A bit more maths and I worked out the optimum throat opening to go with the ports. A trip to my mates and use of his £27K machine opened all the intake throats to where I wanted them.

Sure enough quick test on the flow bench meant not only was the port velocity even across the full length of the port resulting in a very stable flow but it was also reflected in a further 3-4% flow gain.

The new intake port design meant I had room to play with on the intake manifold. The final result of which meant that within the main lift range of the schrick camshaft the flow drop with the intake mani bolted on became so neglible, that on desktop dyno it showed no real change in power and torque other than 4-5hp/tq drop at around 6000-6500rpm.

So fingers crossed and all the science and testing has succeeded in what ctwg60 wanted as a final result. Roll on summer time :-D

p.s. I'll let ctwg60 post up the desktop dyno sims if he wants. Port flow and velocities I'll put up later on tonight or tomorrow.

by jmc Sun Mar 29, 2009 10:06 am

Looks really cool guys - great work on the head and intake manifold.

So JNL - worth doing the inlet manifold on mine do you think?

by ctwg60 Sun Mar 29, 2009 11:08 am

I think it maybe worth a look but could the exhaust ports be improved on a CNC Head??

Anyway here's the comparison graph. We have my existing plot, the unrestricted (no manifold) previous JNL Head and The New Head and Inlet (My Head).

Not much in it is there!

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by **Toad** Sun Mar 29, 2009 11:19 am

Bloody hell....

Quite looking forward to seeing how this pans out. Smile

by ctwg60 Sun Mar 29, 2009 11:26 am

Toad wrote:Bloody hell....

Quite looking forward to seeing how this pans out.

Dyno2003 is all theory but it shows a right direction to work in I feel. Getting a little paranoid about the TB ruining the result in stock form but I don't want to worry about part throttle stuff etc. Lets keep it simple, well relatively! Laughing

by jmc Tue Mar 31, 2009 11:34 am

Flowing the throttle body is easy CTW. You don't need to touch the butterfly valves (which can affect idle), but you can round off the inlet which has a really steep shoulder. I built one up with Liquid Weld and then sanded it back, and have also tried ally welding. To be honest I prefer the liquid weld approach.

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Makes a big difference to the look, and while I've not had one flow tested, it must make some difference.

by ctwg60 Tue Mar 31, 2009 12:04 pm

I guess the TB flow would only be a possible Mass Air Flow restriction above a certain RPM. I think I need to find out the appetite of a high powered g60 engine for air and at what revs it would be a restriction. Smile

Thanks for the images JMC.

by **mrbeige** Tue Mar 31, 2009 1:35 pm

ctwg60 wrote:Wouldn't of happened without your forum buddy! Thanks!

by ctwg60 Tue Mar 31, 2009 2:08 pm

Haha I still don't know what this smilie means! Rub

by dirtytorque Wed Apr 01, 2009 1:06 am

\/\/\
the smiley on the right is giving the smiley on the left a blow job.

by ctwg60 Wed Apr 01, 2009 1:30 am

by **Toad** Wed Apr 01, 2009 9:39 am

Doesn't last long.

by ctwg60 Wed Apr 01, 2009 11:48 am

Like my exhaust staying in one place! Which has now been back to Pipewerx and now has the coupling that attaches to the flange for the rest of the ehaust to bolt to, now welded to the exhaust manifold. It appears that the rose joint that failed causing blowing which was then replaced with another circle rose thing (technical term) and then ended up locked solid to stop that one leaking and thus ended up with the flexi in the cat bypass to compensate. Has now had to be welded to the manifold downpipe to stop the excessive movement and rubbing that has been happening. I've had so many issues with my G-werks manifold it's untrue. Guess it just a bad one as I haven't heard anyone else complaining. It's not something you can simply return and get another as it's a bit of a b'stard to fit!!

Rant over just thought others should know!!

Oh yes now thats been done it sits nicer at the back keeps bloody well still, and is much quieter!! Thank God! Mad

Darren said he would refund on return but I decided it would be more hassle than it's worth so left it on, but now it's finally sorted it will stay I just hope I don't have anymore issues. Two years it's taken for it to be sorted out due to one thing and another!! Sleep

by dirtytorque Thu Apr 23, 2009 11:15 pm

ctwg60 wrote:OK big image post of what I've been up to.

OK just to expand on the gearbox post previously. I currently have a CTN gearbox which was used because I wanted reliable traction in summer and winter and 1st and 2nd on the original CBA box was just letting me down all the time. So I got myself the CTN diesel box as I did't want to swap ratios around, this meant I had great traction in 1 and 2 a longer 3rd seeing me to about 96mph and a silly 4th giving slower acceleration and topping out at 136mph at 6200rpm which helps with fuel economy but wasn't ideal. 5th was great as it was more of an overdrive gear for steady cruising and has saved me a fair few pounds not spent on petrol. I then worked out from my original power run at awesome what sort of torque I had at the wheels and started thinking about the new engine and how it's increase in torque might affect my current traction and gearing. As I expect the car to have more torque lower down I conservatively estimated I might make some extra 20lb/ft with the 2 ltr block giving me around 220lb/ft at the wheels. I then considered I may end up in the same situation I had with the CBA and thought I'd do something about it. I didn't want to spend loads of money on a LSD yet so I found an ASD code diesel that is a straight fit for the corrado and with a taller again 1st and 2nd of around 40mph in first 1st at the 6000-6200 limit and 68mph in 2nd. I must point out I'll probably be changing gear at about 6000rpm in most gears and am running standard 15" wheels so I really do need the tallest gears available to get the most work done by the engine in the shortest time.

Now when it comes to the 3rd and 4th of the ASD box it all gets a bit silly 100mph in 3rd and 145mph in 2nd. :laugh: I needed to change these as the drop in wheel power from 2nd to 3rd and then 3rd to 4th was silly and would make my car feel slower than it should so I got hold of a corrado 1.8 16v box code AYK and stripped it down for it's short 3rd and 4th which would reduce the 100mph 3rd down to around 90mph and the 145mph 4th down to 125mph so these would then be shorter than the current CTN but maintain traction in 1st and 2nd and still have the economy of the diesel 5th.

This is what it looks like

Gearbox:- ASD 1.9L D+ AYK 3+4 ratios
Tyre:- Michelin all patterns 205/50 x 15
-------------------------------------------------------------------------------------------
Top Gear gives 29.779 MPH/1000 RPM and a top speed of 184.632 MPH at 6200 RPM

Engine speeds in top gear:-
30 MPH = 1007 RPM 40 MPH = 1343 RPM 50 MPH = 1679 RPM 60 MPH = 2015 RPM
70 MPH = 2351 RPM 80 MPH = 2686 RPM 90 MPH = 3022 RPM 100 MPH = 3358 RPM

Top Speed in 1 gear = 40.138 MPH
And changes into 2 gear at 3653 RPM dropping 2547 RPM
Top Speed in 2 gear = 68.121 MPH
And changes into 3 gear at 4557 RPM dropping 1643 RPM
Top Speed in 3 gear = 92.691 MPH
And changes into 4 gear at 4465 RPM dropping 1735 RPM
Top Speed in 4 gear = 128.722 MPH
And changes into 5 gear at 4323 RPM dropping 1877 RPM
Top Speed in 5 gear = 184.632 MPH
******************************************************************************************

My current box...........

Gearbox:- CTN 1.9L D
Tyre:- Michelin all patterns 205/50 x 15
-------------------------------------------------------------------------------------------
Top Gear gives 28.274 MPH/1000 RPM and a top speed of 175.298 MPH at 6200 RPM

Engine speeds in top gear:-
30 MPH = 1061 RPM 40 MPH = 1415 RPM 50 MPH = 1768 RPM 60 MPH = 2122 RPM
70 MPH = 2476 RPM 80 MPH = 2829 RPM 90 MPH = 3183 RPM 100 MPH = 3537 RPM

Top Speed in 1 gear = 35.061 MPH
And changes into 2 gear at 3475 RPM dropping 2725 RPM
Top Speed in 2 gear = 62.550 MPH
And changes into 3 gear at 3982 RPM dropping 2218 RPM
Top Speed in 3 gear = 97.393 MPH
And changes into 4 gear at 4428 RPM dropping 1772 RPM
Top Speed in 4 gear = 136.355 MPH
And changes into 5 gear at 4823 RPM dropping 1377 RPM
Top Speed in 5 gear = 175.298 MPH
******************************************************************************************

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I thought I'd also post some images of the stripping down procedure.

OK the case is off in this picture which is pretty straight forward once 5th gear is removed which can be tricky but with a strong puller and a little bit off heat came off ok. In this picture I'm using a 10 tonne hydraulic jack with a large diameter bearing puller placed under 2nd gear to pull 2nd 3rd 4th, syncro hub and bearing sleaves. Even at 10 tonnes of pressure it still would not budge until heat was applied to the syncro hub. Then it let go with a mighty bang and the whole assembly jumped on the bench. It took some hard work to pull the lot off believe me. :sly:

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This is the tool kit I bought to pull all the gears.

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I used some of the other puller kit to remove 1st gear from the pinion shaft so as I could sell on the 3.68:1 pinion shaft and crown wheel/diff assembly.

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I did the same with the ASD which was easier since I now had experience. and to get each bearing sleeve and syncro hub back on I simply heated them up slightly and dropped them on to the shafts.

Here is the input shaft all done

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And the finally assembled gearing

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The hardest bit then was applying a sealant around the entire casing before reassembly.

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Believe me all this looks straight forward but it came apart a few times because things weren't right or did fit but I got there in the end. It still needs 1/4 turn on the case bolts and the shift tower sealing up but it's selecting all gear including reverse :rolleyes: thank god and can be fitted when required. I'll be running with the current box for engine comparison and simplicity of running in etc. but will slide the new box in when the time comes.

Just read this again properly,and it makes alot of sense.I think I may go the same way.
I beginning to see your thinking.Allowing the engine to do the most work in moving the car forward over a given period of time.
Hmm. Twisted Evil

Efficienncy and power. Cool

No point having short gearing if the engine can't make use of it.And I have reservations about LSD's now after a friends experience with them in the wild.
Hopefully this will be one of my winter projects.

I just need to make the extra torque/power to warrant it 1st. Smile

It is always interesting to see a list of 1/4 mile times at the pod and your see a person do a similar time or quicker ET with a slower end terminal speed.
One of my favourite mind benders this.
I.e just because two cars have achieved the same speed it doesn't mean they will have achieved the same distance.The other factors in the cars makeup have an effect on this i.e power torque available at the wheels and how it is able to use it.Gearing.
I never get bored of that one.

by ctwg60 Fri Apr 24, 2009 2:59 am

No I haven't fathomed the speed distance thing either and I think it's because speed is relative and from an early age speed means something to us which we think is tangible when in fact it isn't tangible at all. Speed, putting it simply is b***S***.

It's like trying to get your head around the concept of the 4th dimension, the concept of terminal speed and distance is a mind bender and the maths behind it a little complicated.

Glad you've understood were the longer gearing concept is coming from.

The conundrum is basically how can one car get to the 1/4 mile finish line quicker but be going a slower speed than the car it beats??? It's madness!

by **Toad** Fri Apr 24, 2009 4:37 am

Well, the area under the speed/time curve is equal to the distance travelled, so you'd want to accelerate as quickly as possible to start with then the rate of acceleration would need to drop off if you were to cover the quarter mile quicker, but with a lower terminal velocity.

You just need to use a bit of integration and differentiation. :p

by dirtytorque Fri Apr 24, 2009 4:57 am

Toad wrote:Well, the area under the speed/time curve is equal to the distance travelled, so you'd want to accelerate as quickly as possible to start with then the rate of acceleration would need to drop off if you were to cover the quarter mile quicker, but with a lower terminal velocity.

You just need to use a bit of integration and differentiation. :p

It's all in the get away then Twisted Evil

Then you just need to maintain.

That was very very Well put Thomas.
Hmm.

by ctwg60 Fri Apr 24, 2009 1:32 pm

Nobody likes a smart arse, Tom! Raygun

by junkie Fri Apr 24, 2009 1:39 pm

My pod times were like that, the quickest 1/4 i did was at a slower speed, and the quickest speed i crossed the line was not so quick.

by **mrbeige** Tue May 26, 2009 1:33 pm

So, Chris, you've gone very quiet, what's happening?? Smile

by ctwg60 Wed May 27, 2009 12:33 am

I bought a horse recently so have been pre-occupied. Still on for doing the head around the end of the summer but as it's needed daily and will need a remap immediately due to changing the injectors and the lower m.a.p fueling will be way out so I need to be organised when I do it. Oh yeah I need money aswell!

Enjoying driving it and the break/change of scenery for now! Can be a very obsessive hobby.

Check it out...

by dirtytorque Tue Jun 02, 2009 12:33 pm

ctwg60 wrote:I bought a horse recently [/url]

As you do.
Laughing

by ctwg60 Tue Jun 02, 2009 12:59 pm

dirtytorque wrote:
ctwg60 wrote:I bought a horse recently

As you do.

Real conversation stopper on a car forum anyway, actually, always!! Laughing

by dirtytorque Wed Jun 03, 2009 1:02 am

ctwg60 wrote:
dirtytorque wrote:
ctwg60 wrote:I bought a horse recently

As you do.

Real conversation stopper on a car forum anyway, actually, always!!

yup.

What did you use to punch dent your rad support mate?
I have a feeling I have cut out the section where you have the rad punched into. Laughing

I'll take another look at your pics.

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