Compressor Maps

[Bean]

V-M made an adjustable sprocket by machining two sprockets and combining them to make it adjustable.

Keebs - one comment on the manifold being restricted: I personally think the stock manifold is a beautiful casting that *should* be capable of flowing pretty decent power - I think the source of the restriction is that .36 A/R exhaust housing. My plan is to change the outlet to a T25 and run a BW EFR6268 or 6768.

I don't know what your power goals are, but I was looking at 300 RWHP as my goal which is fairly modest, but should still be fun with a 1:10 power to weight ration, and the drivetrain still has a decent chance of surviving.

I should start another thread to discuss N9TE internal mods so we don't hijack Stewart's thread anymore - but Im seriously interested in the rod and piston recipe someone in the industry comes up with. I can only search specs and I was dabbling with the idea of 94mm air cooled VW pistons and custom rods with an offset ground crank making use of 4G63 big end rod bearings.

Apologies Stewart! Got a little carried away there.

Rabin

[keebs]

Yea sorry Stewart didn't mean to get carried away.

[Stewart]

All cool with me! Without sharing knowledge no one would learn nuttin!

[Stewart]

Just been setting up a Simulation for keebs . I plugged in GT Super T3-60, AR .0.48 and boost of 17 psi at turbo, 60% intercooler efficiency and 2 psi drop to 15 psi in manifold. This is with a Dani cam set straight up and 7.5 compression. I use a mixture of 12.5 and inlet at turbo temp of 20 deg C. I think you'll find this accurate enough for us to work on manifolds and cams.

1/ Image is cam and turbo spec.

2/ Is a graph prediction torque and power

3/ Look closely here and we see piston speed reaching 3480 ft/min at 6500 rpm. As a rule of thumb for cast alloy pistons 3500 ft/min is max speed for street use. We will probably find the std ecu rev cut out is around 6500, I think.

Notice the Ignition timing prediction at the end of the table, as well. I have proven this prediction myself many times and am happy to say with mixture at 12.5 it works as a great base for ign maps. It is the base start for your map at atmospheric pressure in the manifold, as in no boost, no vacuum, wide open throttle.

These are based on Keebs std engine and a small turbo manifold. Maybe opening up the N9T std unit or making a small equal length pipe runner system will bring the T3 alive. With an opened up exhaust manifold for smooth even delivery, more static compression and a new cam will get the T3 spooling up much earlier.

This is stuff I have been working and testing for a while now and I'm confident in sharing this as a good base of data to start the next N9T for Keebs and Bean!

[keebs]

Wow I guess it might have more power than I thought, and the timing calculation is surprisingly close. The dani cam will suit my needs with a bit of tweaking. I'm not looking for a motor that goes flat up top. Thanks for taking the time to put this together.

[Stewart]

I have spent some time today and have found if you advance the Dani by 2 deg at the cam, the engine will come alive for you. There is a lot of things happening in a turbo cam timing graph figures wise. Advance any single cam and the inlet opens earlier and closes earlier. Good for Dynamic compression increase but also it gets the maximum lift of the valve close to the maximum piston speed position. Another is with the exhaust. Open the valve earlier, lets out some energy on the piston which then blows to the turbine making it spool up faster! More air gets delivered from the compressor. Maximum piston speed happens at an angle on the crank and can be found using a formula 2x bore/stroke then getting the inverse Tangent for that. This engine bore= 91.7/81.6mm. So 66 deg after tdc and 66 before tdc. Check the cam timing graph and we see valve lift at 360+66= 426 is slowing down towards it's maximum lift. Sneaky little trick I hope will explain a bit of my mad mutterings!

1/ Is your engine compared to plus 4 crank deg and retuned to suit.

2/ Dani timing graph Advanced 2 deg at cam.

3/ Redone prediction table and notice the change in the ign timing!

4/ Is 2 deg on cam and static compression lifted to 9.5. You can see what a little change in static and cam timing can do in this graph. Your engine now compared to your engine with 9.5 and 2 deg adv on the cam. What this shows is you can now run less boost for better longevity, as in

5/ 9.5 at 12 psi in manifold gives close to the same torque you have now but earlier with the same power. Magic.

All worth a good hard look I reckon.

By the way I've found French vehicle valve springs notoriously soft and I can calculate what is best if we know the weights of valve train componants. Adding more lift to a std spring makes for a diabolical valve train which can give valve float at all sorts of different RPM. That either gives noisy operation, difficulty in tuning out a surge, harshness all sorts of crazy stuff. ( Some of the reason I'm crazy, I'm told.)

En Avant!!!!

[keebs]

Holy cow. I wonder if dani cams were ground 2 degrees retarded intentionally and meant to be advanced for race use. I'll try to get a cam gear slotted tomorrow so I can try it out asap.

I don't know anything about the valve springs. Since its a single spring I'm sure it suffers from harmonic problems. Beehive springs would be the way to go for resonance stability and low inertia.

[Bean]

Good God Stewart - that's an incredible bit of deduction you just did. If this pans out for Keebs the improvement is astounding!

I sure hope you can get the cam sprocket slotted asap Keebs - verifying this finding will be an amazing discovery if it pans out.

Rabin

[Stewart]

Yes, if you can get beehive ones for the job. I used a file the right size for a key way and a protractor to get a new groove in the cam gear on my engine, is it easy enough to do that on yours? Should liven the old lovely up!

So cam timing should be 23/75, 87/22 intake centre at 116 atdc.

What is the running clearance recommended for the Dani? 0.012" hot?

If we can weigh an inlet and exhaust valve, a rocker and get a dimension for the spring height installed / valve closed, we can get a spring set up to suit the cam exactly. There is much torque to be had from getting this right, too.

Also, I'd like to confirm the rocker ratio at 1.5. for the mathematics. ( I wish I had some of these bits here but I reckon we are close.)

If you type in "Valve Train Float" there are some interesting videos to watch. Amazing what might go on under the hood!

[keebs]

A friend of mine has a milling machine so if he's home I can get it done easy. N9T doesn't have a key way. A boss on the cam locates the sprocket and it's only held by clamping force. Std valve clearance is .008 in. .012 ex. cold. I don't know if dani used a different spec.

[Bean]

Man this thread has progressed fast!

Stewart - I've got a container full of disassembled head parts - just need to find a way to accurately measure it.

I'm also completely unaware of any Danielson installation instructions. Joe Grubbs and possibly George Nunez are the only ones I know of still active that purchased direct from Politecnic and would have seen any special install directions.

Valve clearance should be the same as stock since valvetrain is stock. I'd be totally up for a set (or 2 depending on cost) of custom beehive springs.

Cam sprocket - I thought of slotting the mounting holes as well, but wanted to find a diamond coated shim to fit inbetween to ensure it kept its position. Likely overkill - but seemed like good safety measure.

http://www.esk.com/en/products-brands/products/frictional-connection-elements/friction-enhancing-metal-shims.html

Rabin

[keebs]

Today so far I've gotten the gear slotted. Wasn't able to get hold of my buddy so I broke out my file and went to town. The good news is it's got more pep down low, didn't take it up to full boost but it feels promising. Valve lash in my experience has more to do with the cam ramps than valve train. Wouldn't worry too much about shimming the cam gear. I've worked on a few 600-1000cc race bikes that had nothing more than slots. For valve springs PAC racing probably has one that will do, figure 3-400usd for springs and titanium retainers. On to the bad news. My cam chain tensioner mounting bolt has come loose, guess that's the noise I've been hearing the past few months lol.

[Bean]

That was fast - well done!

I tend to over think and over do stuff all the time. If I can find a shim that works easily I'll do it anyway since I'm still a ways off from my build.

The one bonus for a ridiculously long buuld is that the costs are spread out over years!

Rabin

[keebs]

Over thinking is part of the fun. Not like we can just order off the shelf parts. That's why I love the 505, every one I see is modified differently with one off custom parts. Nothing wrong with taking your time and doing it the way that makes you sleep best.

For months I've been over thinking a way to mount subaru sti struts so I can use those sweet brembos and super light gold wheels without losing suspension travel.

[Stewart]

sounds like a plan !!!!!.

[Stewart]

Out of interest about building up a nice engine spec to run a stand alone ECU compared to what the 505 had standard, I thought about comparing what the sim predicts and what Keebs and Bean have experienced as a good start point. So I ran through a standard N9TE running at the same temps and intercooler efficiency. I ran the Std 505 sim with a T3-50 at 12 psi in the manifold and Keebs engine spec with a T3-60 at 12 psi manifold and his Dani cam installed straight up. My question is do the two graphs relate to real world feel and facts? The second graph is an approximation of a std N9T engine with dani cam plus 4 crank degrees, designed headers to turbo and T3-60 at 12 psi. compared to std. N9T..

My Avatar speaks for itself..................

[andrethx]

My Avatar speaks for itself..................

if you go to your account settings and select "my settings," and go to profile information>member title, you can change the title above your avatar from "peugeot enthusiast" to "junior scientist," "double-naught spy" or whatever you want.

please resume your technical discussion already in progress...

andré

[keebs]

The first graph is probably close enough, but that second graph might be a liar. It's rare not to see a power increase up top with a tubular manifold.

[Stewart]

So it would be close to this?

[Bean]

I promised this a while back, but I'll comb the FSM's for any applicable charts and info that might belp build the model.

Can you confirm that the simulation is predicting wheel HP or flywheel Hp?

Rabin

[keebs]

Now that looks closer to whats expected. The numbers might be wrong but the curve is more accurate.

[Stewart]

Oh, good. The numbers are directly related to the air temp at turbo inlet and the intercooler efficiency from here then! Beauty.

Bean, the prediction is for flywheel. There are a few areas in the sim like exhaust manifold layout with such terms as , " HP manifold with or with out cat"and " large tubing runners or small tubing runners, std manifolds with or without cat" so once we get an accurate curve for torque and such we can nail down what style of exhaust the n9T is considered to have for the sim and we can then tickle cam and boost to test before spending money. I'm suggesting things like what turbo on a std manifold or this turbo on a tubular design or bigger inter cooler on a std engine with x amount of boost. It has been working well so far for me on the old stuff I do at work and in the Jethro Bodine Nuclear Science Laboratory in the garage at my house. ( the garage also combines an accurate replica of The Cone of Silence from Get Smart, fitted with a beer fridge, of course.)

There is a thing called adiabatic process which helps in calculations for air temp and density used by turbo manufacturers to give air flow figures. This formula is also used in the sim . Inlet temp and intercooler efficiency are big game changers as well as static compression and cam timing figures. Say if you want more torque from the engine as it stands, the first thing is to wind up boost. well with the sim we can, until we get to a point of diminishing return, without having lifted a spanner or blown an engine. That's where the fun is. The cool part is to increase bore or stroke with the rest of the engine as is and the sim will give a sweet combo within machine limits. Will I give that a go with a max 94mm bore and say 1mm more stroke ( which will be good) and we could compare that with a 94mm bore, stand stroke and more static with the dani cam?

[keebs]

Hopefully some of this will help calculations. The exhaust manifold primaries are about 38.5mm, internal diameter of the log looks to be 1.5x primary diameter, and collector diameter 48.6mm. Cyl 1 is within 55mm flange to flange, and shows 940c egt at 6300rpm. For iat my sad intercooler goes from an ambient 23c to 42c blasting up an on ramp. Std con rod is 137.25mm, and the new planned rod will be 142mm for me at least.

[Stewart]

Keebs, may I use 1 bar ( 1 atmosphere) as an example for your inlet at 23 C to expect ( 2 x 23 deg C to equal 46C.)

At 42 deg C I understand that your inter cooler is giving 4 deg reduction in turbo outlet temp. That gives me a 9.5 % efficiency for the heat exchanger.

So, first graph is what should be close to what you have today.

The second is with 94mm bore and a longer rod, plus 9.5 :1 comp and Dani advanced 4 crank degrees. Every thing else as of today.

The third is with the Super T3-60, 0.48 AR arunning into a better intercooler.

Do my figures look sensible?

[keebs]

That curve looks good. If this proves to be correct I might just leave the cam straight up and set redline at 8k.